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Surgery Howard B. Seim III DVM, DACVS Colorado State University Surgical Management of GDV If you would like a copy of the illustrated version of these notes on CD and a video of this surgical procedure on DVD, go to www.ivseminars.net and click Video Vet. Key Points Introduction: Patients with GDV are considered critical care cases; every minute of presurgical treatment is vital to a successful outcome. Survival is generally determined by early and appropriate presurgical management; not surgery. Efficient presurgical treatment usually involves a minimum of two people. Both gastric decompression and shock therapy should be done simultaneously. If this is not possible; decompression should be performed first. It is stated that gastric decompression is the single most important factor in reversing cardiovascular deficits in patients with GDV. Decompression: Generally, orogastric intubation can successfully be performed in 80 - 90% of GDV patients. Decompression vial flank needle puncture should be attempted in cases difficult to intubate. Technique: The stomach tube is measured to the last rib and marked with a piece of tape. A stiff foal or mare stomach tube with a smooth tip works best (having several diameter and stiffness tubes is ideal). Apply adequate lubrication to the tube. Place a functional mouth speculum; generally a roll of 2" tape secured in the mouth with tape encircling the muzzle. As the stomach tube is passed, you will generally meet resistance at the esophageal-stomach junction. Pass the tube firmly in a twisting manner to pass the lower esophageal sphincter. If unsuccessful, place the patient in various positions and attempt to pass the tube (i.e., elevate animal at 45 degree angle with rear feet on floor and forefeet on table, right lateral recumbancy, and left lateral recumbancy). This movement may encourage the stomach to rotate enough to allow tube passage. Be careful not to position the patient in dorsal recumbancy as this will increase abdominal visceral pressure on the caudal vena cava. If still unsuccessful, try different diameter tubes; try a smaller diameter, more flexible tube and proceed as described above. If still unsuccessful, attempt to remove some of the air in the stomach by placing a l6 or l8 gauge needle at the point of distention in the right flank region. Ping the area to make sure the spleen is not under the proposed trocarization site. After trocar decompression, attempt to pass the stomach tube as described above. If still unsuccessful, sedate the dog with a narcotic (Oxymorphone .11 to .22 mg/kg IV) and try to pass the tube again. Mild sedation is recommended if the patient strongly resists physical restraint. Success in passing a stomach tube depends on the skill of the operator and available assistants. If you are successful at passing a stomach tube, but plan to refer the patient to a referral surgical center for gastropexy, transport the patient with the tube remaining in the stomach (i.e., taped to the mouth) or bring the tube out through a pharyngostomy or maintain it as a nasogastric tube. If a stomach tube was successfully passed, stomach contents should be evaluated for color and presence or absence of necrotic gastric mucosa. This may give an impression of gastric viability. Fluids: Shock dosage of polyionic isotonic fluid is administered to expand the vascular compartment. For convenience, lactated Ringer's or Normosol-R is generally used. One or two indwelling cephalic catheters are placed and clinical signs are monitored to establish proper fluid therapy. Referral: If you are successful at passing a stomach tube, but plan to refer the patient to a referral surgical center for gastropexy, transport the patient with the tube remaining in the stomach (i.e., taped to the mouth) or bring the tube out through a pharyngostomy as described below.
If still unsuccessful - a temporary gastrostomy can be performed () The patient is placed in left lateral recumbancy with the right flank area clipped and surgically prepared. Heavy sedation and local infiltration of lidocaine or light general anesthesia is performed. A 4 - 5 cm incision is made in the skin over the point of greatest gastric distention (generally 1 - 2 cm caudal to the 13th rib and 2 - 3 cm distal to the transverse processes of the lumbar vertebrae). A grid technique is used to gain entrance into the peritoneal cavity. Due to severe gastric distention the stomach wall is pressed against the abdominal wall and easily identified through the flank incision. The stomach wall is sutured to the skin using a simple continuous pattern with 3-0 Maxon. This is done prior to incising into the stomach lumen. A #11 BP scalpel blade is used to puncture into the lumen of the stomach. Gas and stomach contents are expelled under pressure so stand back! The gastric mucosa is evaluated for viability. Disadvantages of gastrostomy include: the stomach is sutured in its rotated position and more time is required when definitive surgical treatment is performed due to the necessity of closing the gastrostomy. Shock: Once the stomach tube has been passed into the stomach or gastrostomy performed, the stomach is lavaged with warm water. If a stomach tube was successfully passed, the stomach contents should be evaluated for color and presence or absence of necrotic gastric mucosa. This may give an impression of gastric viability. Surgical Treatment: Surgical procedures utilized in the treatment of gastric dilatation volvulus can be divided into two categories; 1) immediate decompression and 2) therapeutic gastropexy. Immediate decompression is performed with a successfully passed stomach tube secured to the patient or temporary gastrostomy as described above. Therapeutic or prophylactic gastropexy techniques are described below. Gastric repositioning: Anatomic repositioning of the stomach is necessary to prevent recurrence of GDV. Repositioning may occur spontaneously at the time of decompression. Knowledge of normal anatomy is necessary to understand how repositioning is performed. In each case the same maneuver is performed to derotate the stomach. The pylorus, located near the cardia of the stomach, is grasped by on hand and elevated as the other hand presses down on the fundus of the stomach. Reduction is generally easily performed if the stomach has been decompressed. The spleen usually will be carried back to its normal location when the stomach is derotated. Exteriorizing the spleen may facilitate derotation of the stomach. Spleenectomy is rarely performed, but may be necessary if splenic vessels are infarcted. The greater curvature and fundus of the stomach are examined for areas of necrosis. If necrosis is present, the prognosis is unfavorable to grave. Belt Loop Gastropexy: This technique is based on the construction of a sero-muscular antral flap attached around a segment of transversus abdominus muscle. A horseshoe shaped incision is made in the serosal layer of the antral portion of the stomach with its base at the greater curvature. The sero-muscular portion of the stomach is identified by grasping full thickness of the antral wall between the thumb and index finger and "slipping" the mucosal and submucosal layers away so only the sero-muscular portion of the wall remains between thumb and finger. The sero-muscular layer is incised with scissors and the horseshoe shaped sero-muscular antral flap is dissected and elevated of the submucosal layer. The stomach is replaced in the abdominal cavity in normal position and the sero-muscular flap lined up with the transversus abdominus muscle. Once this optimal location is discovered, two longitudinal incisions (along the fibers of the transversus m.) are made in the transversus abdominus m. The segment of muscle between the incisions is undermined. The sero-muscular flap from the stomach (i.e., belt) is passed through the transversus abdominus m. (i.e., loop) and sutured to itself to complete the "Belt-Loop" gastropexy. 2-0 monofilament absorbable synthetic suture in a simple interrupted or continuous pattern is used to secure the flap in place. Advantages of belt loop gastropexy include: it is relatively easy to perform alone and in the middle of the night, it can be performed quickly, and it is an effective means of permanent gastropexy. Incisional gastropexy: This technique is based on the construction of a seromuscular antral flap attached to a scarified segment of transversus abdominus muscle. A 2-3 cm incision is made in the antral portion of the stomach. The bleeding surface of the antrum is brought to the right body wall. With the stomach in a normal position, the bleeding antral surface is touched to the peritoneal wall to create a blood mark on the peritoneum. This is the location of the gastropexy. The peritoneum and transverses abdominus muscle are incised creating a mirror image defect of the stomach flap. The stomach flap incisional defect is sutured to the abdominal wal incisional defect with simple continuous or simple interrupted synthetic absorbable suture. Postoperative management Usually 3-4 days of intensive monitoring and treatment is necessary for the successful management of GDV patients. Postoperative considerations are listed below:
Acquired Oronasal Fistula Repair Definition Acquired oronasal fistulae are abnormal communications between the nasal and oral cavities caused by trauma or disease. Introduction Acquired palatal defects are most often caused by dental disease. An oronasal fistula results when a deep maxillary periodontal pocket progresses to the apex of the tooth, lysing bone between the apex of the alveolus and the nasal cavity or maxillary sinus. A fistula may also result from trauma (i.e., bite wounds, gunshot wounds, blunt trauma to the head, electrical burns) or may be a complication of surgery (e.g., mass excision or ventral rhinotomy), radiation, or hyperthermic treatment of oral lesions. Foreign bodies lodged between the dental arcades may cause pressure necrosis of the hard palate and subsequent development of an oronasal fistula. Ingested food that passes through the fistula into the nasal cavity may be expelled from the nostril by sneezing. Chronic rhinitis is common. Clinical presentation Signalment: Any breed or gender may acquire an oronasal fistula. Oronasal fistulae that occur secondary to dental disease or tumors are seen more often in middle-aged and older animals. Oronasal fistulae that develop secondary to trauma may occur at any age. History: An oronasal fistula should be suspected in patients with chronic rhinitis and a history of dental disease, trauma, or previously treated oral tumors. Common clinical signs are sneezing and chronic unilateral serous or mucopurulent nasal discharge. Physical examination findings: The diagnosis of an oronasal fistula can be made by identifying an abnormal communication between the oral and nasal cavitiesd Small fistulae associated with periodontal disease are not easily identified unless the area around the involved tooth is explored with a narrow dental probe. If passing the probe into the gingival pocket causes epistaxis, a fistula is present. The palatal aspect of the maxillary canine tooth is a common site for an oronasal fistula. Anesthesia generally is required to probe periodontal pockets. Radiography and Ultrasonography: Radiography and ultrasonography are generally not necessary for diagnosis and treatment of acquired oronasal fistula. Skull radiographs may identify underlying causes of fistulae, such as periapical abscesses, advanced periodontal disease, maxillary neoplasia , or broken and retained tooth roots. Lysis around tooth roots is indicative of periapical abscesses. Laboratory Findings: Inflammatory changes on a complete blood cell count (CBC) may be seen secondary to rhinitis or aspiration pneumonia. Differential Diagnosis: Differential diagnoses include any disease that causes chronic rhinitis (e.g., fungal disease, presence of a foreign body, congenital oronasal fistula, invasive oral neoplasia). These conditions generally can be differentiated based on the physical or histopathologic examination (or both). Histopathologic evaluation should be performed to distinguish fistulae that occur secondary to neoplasia from those associated with infection or trauma. Medical Management: Broad-spectrum antibiotics effective against anaerobes (i.e., chloramphenicol, trimethoprim-sulfadiazine, ampicillin, clindamycin) should be given if severe purulent rhinitis is present. Such animals may benefit from having the nasal infection treated before closure of the defect. With the patient under general anesthesia, cultures should be obtained from the nasal cavity, and the nose and oral cavity should be flushed of debris and exudate. To prevent recontamination of the nasal cavity with food, the animal should be given nothing by mouth for 10 to 14 days. Nutrition can be provided via tube feeding (e.g., tube gastrostomy or esophagostomy) during this time. Surgical Treatment: Most oronasal fistulae require surgical reconstruction, although small or traumatic fistulae occasionally heal spontaneously. A variety of surgical techniques have been described for repair, including simple suturing of the fistula edges, mucosal flaps, mucoperiosteal flaps, double reposition flaps, and two-staged tongue flaps. Successful repair of oronasal fistulae requires a well-supported, airtight, tension-free closure. Flap techniques are more successful than direct apposition of the fistula edges because there is less tension and increased support for the repair. Teeth involved in the fistula should be extracted several weeks before reconstruction of the defect. Central lesions may require that normal teeth be extracted to allow creation of adequate mucosal flaps. If the fistula is of dental origin, it may be necessary to perform a limited maxillectomy (at least 5 mm from each margin) to remove necrotic or diseased bone. Traumatic oronasal fistulae may require stabilization of the maxilla and hard palate with small pins or wire. Interdental wiring using the carnassial teeth or the canine teeth (or both) can be used to help bring bone edges into apposition. Areas where flaps were harvested heal by second intention in 2 to 3 weeks. Preoperative Management: Pediatric patients should not be fasted for longer than 4 to 8 hours. After anesthetic induction the nasal and oral cavities should be flushed with saline-diluted antiseptic solution. Aggressive management of rhinitis (see Medical Management, above) may reduce infection and improve the tissues' ability to hold suture. Surgical Anatomy: The oral cavity proper is the area bounded by the hard palate and a small part of the soft palate dorsally, by the dental arches laterally and rostrally, and by the tongue and adjacent mucosa ventrally. The tongue is attached to the floor of the oral cavity by the lingual frenulum. The oropharynx extends from the level of the palatoglossal arches to the caudal border of the soft palate and the base of the epiglottis. Dorsally the oropharynx is bounded by the soft palate and ventrally by the root of the tongue. The palatine tonsils are found in the lateral wall of the oropharynx. The blood supply to this region originates from branches of the common carotid arteries. The paired major and minor palatine arteries are important. Two or three vessels emerge from the major palatine foramen at the caudal edge of the fourth upper premolar and course rostrally, midway between the midline and the dental arcade. The right and left major palatine arteries anastomose caudal to the incisors. The minor palatine arteries enter the palate caudal to the last molar and lateral to the major palatine artery, then course caudomedially to ramify in the caudal hard palate and soft palate. Surgical Techniques Direct Apposition Direct apposition of the fistula should be performed only if the fistula is very small. Debride the fistula to healthy, bleeding mucosal edges. Incise or debride the margin of the fistula and elevate the edges enough to allow approximation without excess tension. Appose the mucosa with interrupted appositional sutures (i.e., simple, cruciate, or vertical mattress pattern). If necessary, mobilize the palate and suture it over the sutured defect. Single-Layer Flap Repair See the DVD for a detailed video of this technique. Debride the epithelial margin of the fistula. Incise the gingival and buccal mucosa to outline a flap 2 to 4 mm larger than the debrided fistula. Make these incisions perpendicular to the dental arcade. Elevate the gingival mucosa with a periosteal elevator. Then undermine the buccal mucosa until the flap can be advanced across the defect without tension. Using a rongeur, remove infected alveolar and maxillary bone. Expose approximately 1 to 2 mm of the hard palate at the medial aspect of the fistula by excising 1 to 2 mm of mucoperiosteum. Lavage the surgical site with saline. Suture the gingival-buccal flap to the mucoperiosteum of the hard palate in an interrupted approximating pattern (i.e., simple, cruciate, or vertical mattress) using monofilament, absorbable (3-0 to 4-0) sutures. Rotational Flap Repair A rotational or advancement flap may be created from the hard or soft palate, or an overlapping technique similar to that described for repair of congenital oronasal fistulae may be used. Create a flap 2 to 4 mm larger than the debrided fistula. To ensure a good blood supply, incorporate the major or minor palatine artery in palatal flaps. Transpose and suture the flap the over the defect. Granulation tissue fills the defect over the hard palate, and the area reepithelializes within a few weeks. Double-Flap Repair See the DVD for a detailed video of this technique. Double-flap techniques may be used with large dental fistulae and fistulae located in more central areas of the palate. Double-flap techniques provide a mucosal surface on both the oral and nasal sides of the fistula. If buccal flaps are planned to close large central defects, extraction of teeth may be necessary. The extraction sites should be allowed to heal before reconstruction. Do not debride the palatal epithelial margin during debridement of the fistula, because this edge serves as the base of the mucoperiosteal flap and must remain continuous with the nasal mucosa to be effective see. Create a flap in the mucoperiosteum 2 to 4 mm larger than the debrided fistula. Elevate the flap without disrupting the palatal margin of the fistula. Fold the flap over the defect and suture it to the gingival mucosa with interrupted, approximating, monofilament, absorbable sutures for the first layer of closure. This flap provides "nasal" mucosa. Create a rotational mucoperiosteal flap 2 to 4 mm larger than the defect for the second layer of closure. Appose this flap to the gingival mucosa with approximating 3-0 to 4-0 sutures. To ensure a good blood supply, incorporate the major palatine artery in palatal flaps. Patients with a tension free repair should have a predictably successful long term outcome. As an alternative, create one or two mucoperiosteal flaps 2 to 4 mm larger than the defect. Transpose and suture the flap in place for the first layer of the closure. This flap provides "nasal" mucosa. Cover this layer with a mucosal flap (gingival and buccal) to provide the "oral" mucosal layer of the closure. Allow the denuded hard palate to heal by second intention. Postoperative Care and Assessment: Intravenous fluids should be provided until the animal begins eating and drinking (usually within 24 hours of surgery). Soft food should be fed for 2 to 3 weeks, and chewing on hard objects (i.e., toys, sticks) must be prevented to avoid dehiscence or perforation of the flap separating the oral and nasal cavities. If the animal paws at the mouth, an Elizabethan collar should be used. Severe rhinitis should be treated with antibiotics (see Table 21-5). Healing should be evaluated 2 and 4 weeks after surgery. Complications: Most oronasal fistulae are successfully repaired if flaps can be apposed without tension and with a good blood supply. Dehiscence and recurrence of the oronasal fistula are expected if conditions for healing are not ideal. Motion of the tongue against the repair and particulate matter in the surgical site can also lead to dehiscence. Tension, poor blood supply, infection, lack of flap support, and traumatic technique may inhibit healing. Additional attempts to repair recurring fistulae should be delayed 4 to 6 weeks to allow sites of previous flap harvesting to heal, revascularize, and mature before additional flaps are created. Rhinitis should resolve after the fistula has healed if irreversible mucosal changes have not occurred. Prognosis: The prognosis for successful surgical repair of oronasal fistulas is dependant upon the surgeons ability to achieve a tension free closure of the defect. Traumatic clefts may heal spontaneously in 2 to 4 weeks. Signs of rhinitis caused by regurgitation of food into the nasal cavity may be controlled with chronic antibiotic therapy. The long-term prognosis for most patients with nontraumatic fistulae is poor if surgical correction is not an option, because fistulae do not heal without surgical reconstruction. Surgical Management of Brachycephalic Syndrome If you would like a copy of the illustrated version of these notes on CD and a video of this surgical procedure on DVD, go to www.ivseminars.net and click Video Vet. Key Points Definition: Brachycephalic syndrome is a combination of upper airway disorders commonly seen in brachycephalic breeds (e.g., English bulldogs, Boston terriors, Pugs). Disorders associated with this syndrome include stenotic nares, elongated soft palate, and everted laryngeal saccules. Occasionally patients present with laryngeal collapse. Patients may present with any combination of disorders. Synonyms: Upper airway obstruction Diagnosis Clinical presentation: Signalment: Brachycephalic breeds are most commonly affected (i.e., English bulldog, Boston terrier, Pug, Pekingese, Boxer, and Bull Mastiff). The age at presentation ranges from less than one year to 11 years. The majority of patients present between 1 and 4 years with English bulldogs persenting at a younger age than other breeds. There is no apparent sex predisposition. History: Historical findings are generally related to upper airway obstruction and include noisey respiration, heat intolerance, exercise intolerance, cyanosis, and occasionally syncopal attacks. Gagging, retching, and vomiting may also be reported. Historical findings may vary depending upon the number of abnormalities present (i.e., stenotic nares, elongated soft palate, and/or everted laryngeal saccules). Generally, the more abnormalities present the more severe the historical and clinical findings. Clinical signs: The most frequently reported clinical signs in patients with brachycephalic syndrome are noisey respirations and exercise and/or heat intolerance. Moderate to severely affected patients or patients with multiple defects may present with cyanosis and/or syncope. Physical examination: Physical examination is generally normal except for patients with stenotic nares. In patients with stenotic nares the wings of the nostril(i.e., dorsolateral nasal cartilage) obstruct airflow resulting in turbulent air flow and resultant noise. Examining the patient after exercise may exacerbate clinical signs (i.e., noise and exercise intolerance) making diagnosis of brachycephalic syndrome more likely. Oral examination of the awake patient is generally unrewarding as the laryngeal apparatus and related abnormalities cannot be seen without light general anesthesia. Laboratory findings: Results of a complete blood count, serum chemistry profile, and urinalysis are generally normal. Radiography: Diagnosis of brachycephalic syndrome is based on signalment, history, physical examination, and direct visualization of the laryngeal apparatus with the patient under light general anesthesia. Thoracic radiographs are generally recommended to rule out lower airway disorders such as tracheal hypoplasia and pulmonary abnormalities. Differential diagnosis: Any disorder causing noisey respirations, exercise intolerance, cyanosis, and syncope. Included are laryngeal mass, laryngeal collapse, laryngeal paralysis. Medical management: Medical management is directed at decreasing airway turbulence and subsequent inflammation and edema. Strict confinement, antiinflammatory medications (e.g., steroids, NSAIDS), and a cool environment is recommended. As medical management does nothing to change the anatomic deformity of the disorder, it is considered paliative but not curative. Surgical treatment: The objective of surgical treatment is to provide an adequate airway by relieving any anatomic obstruction. Preoperative management: Patients are treated with prophylactic antibiotics. Use of antiinflammatory medication preoperatively is somewhat contraversal. It is probably not necessary in all cases. This author uses the following guidelines to help determine which patients should receive preoperative steroids: patients that present with mild clinical signs (i.e., noise only) are generally not treated; however, patients that present with moderate to severe clinical signs (i.e., severe excersise intolerance, cyanosis, or syncope) are treated with steriods (dexamethasone 0.5 - 1 mg/kg IV) at anesthetic induction. Anesthesia: Anesthetic management is somewhat dependant upon the severity of clinical signs at presentation and degree of airway abnormality. Patients with mild signs may be anesthetized with the clinicians standard anesthetic protocol. Careful evaluation of the laryngeal apparatus is performed prior to intubation and while the patient can still breath on its own (i.e., light general anesthesia). Laryngeal function is carefully evaluated during inspiration and expiration. Patients with moderate clinical signs may need to be preoxygenated prior to induction. Induction should be performed quickly, the laryngeal anatomy and laryngeal function examined thoroughly, and the patient intubated to establish an open airway. Patients with severe clinical signs should be preoxygenated 5 to 10 minutes prior to induction. A vagolytic agent (i.e., atropine) should be considered 10 to 15 minutes prior to induction because vagal tone is generally increased and cardioinhibitory reflexes are enhanced. Induction should be quick, examination of the laryngeal anatomy and function performed, and the patient intubated to establish an open airway. Regardless of severity, patients are maintained on isoflurane and oxygen. Laryngeal examination: Once the patient is under a light plain of anesthesia the mouth is forced open and the laryngeal function evaluated. Care is taken to observe for evidence of largngeal collapse I , elongated soft palate , and everted laryngeal saccules and . Surgical anatomy: The soft palate in the dog forms a long and broad movable partition between the oral and nasopharynx. The cranial border is attached to the bony palate; the caudal margin forms the dorsal border of the opening from the mouth into the pharynx. This portion of the palate is in contact with the epiglottis during normal inspiration; during deglutition, the epiglottis moves away from the soft palate to protect the opening of the glottis. At the same time the soft palate moves dorsally to close the nasopharynx and prevent regurgitation of material into the nasal cavity. The dorsal nasopharyngeal surface has a mucous membrane lining continuous with that of the nasal cavity and a slightly convex contour. The mucous membrane of the ventral concave surface is a continuation of the lining of the hard palate and is referred to as the oral surface of the soft palate. Relevant pathophysiology: Intromisson of an elongated soft palate into the laryngeal inlet during respiration significantly obstructs air passage into the glottis. Stenotic nares, when present, contribute to the severity of the occlusion by increasing the inspiratory effort (and subsequent negative pressure) thus drawing the soft palate deeper into the larynx. Edema and inflammation result from friction against the epiglottis during each respiration. The resultant thickening further lessens air flow. As increased inspiratory effort continues, increased negative pressure in the airway encourages laryngeal saccules to evert. Positioning: Patients may be positioned in ventral or dorsal recumbancy. Stenotic nares: The author prefers ventral recumbancy with the head supported on towels so the head position is normal and functional. Elongated soft palate and everted saccules: Patients can be operated in either ventral or dorsal recumbancy. In dorsal recumbancy, the maxillary canine teeth are taped securely to the operating table. The mandibular canine teeth are taped to an ether stand situated over the patients head. The mouth is forced open with moderate to severe force. This positioning is critical as oral cavity exposure is key to adequate visualization and instrumentation. In ventral recumbancy, the maxillary canine teeth are 'hooked' over the bar of an ether stand and the mandibular canine teeth taped to the operating table in such a fachion that the mouth gapes open. Surgical technique: The surgical technique varies depending upon the defect to be repaired. Stenotic nares: Stenosis is decreased by removing a horizontal wedge of alar cartlidge from the wing of the nostril. The flap created is sutured to remaining tissue of the wing of the nostril using 3-0 or 4-0 Dexon or Vicryl in a simple interrupted suture pattern. Two or three sutures is all that is generally required to complete the nasoplasty. Presurgical tracheostomy?: Use of a presurgical tracheostomy greatly facilitates exposure and visualization of the soft palate and laryngeal saccules. However, it is not necessary in the majority of patients. The author considers use of a tracheostomy in patients that present with severe clinical signs and have a combination of defects to repair. Tracheostomy is perferred over exiting the endotracheal tube through a pharyngostomy as the tracheostomy can be used in the postoperative management of the patient if necessary. In our hospital, regardless of the severity of the airway obstruction, the patient is recovered in a critical care environment and instruments necessary for an emergency tracheostomy are readily available. Elongated soft palate: The patient is placed in ventral or dorsal recumbancy with the mouth opened widely (see positioning). A broad malleable retractor is used to retract the tongue caudally; this greatly facilitates visualization of the soft palate and laryngeal structures. A head lamp facilitates visualization but is not necessary. Since postoperative edema and swelling are of major concern following soft palate surgey, it is important to keep surgical trauma to a minimum. Use of clamps and electrocautery may cause excessive surgical inflammation and should be avoided. The soft palate is evaluated for extent of resection. A Babcock or Allis tissue forceps is used to grasp the caudal margin of the soft palate. The length of the soft palate in relation to the tonsil and epiglottis is examined. The soft palate should extend no further caudal than the midpoint of the tonsil. Alternately, the incision is made at the point where the soft palate just slightly overlaps the tip of the epiglottis. Once this line of excision is determined, a 3-0 or 4-0 Dexon or Vicryl stay suture is place in the soft palate on each lateral margin of the proposed excision. A Babcock or Allis tissue forcep is used to grasp the caudal margin of the soft palate. The incision is begun from the left or right margin and one-third to one-half of the soft palate is incised. 0 Using the long end of one of the 3-0 or 4-0 Dexon or Vicryl stay sutures, the incised nasal mucosa is sutured to the incised oral mucosa using a simple continuous suture pattern. See 1 Dexon or Vicryl is chosen because of its soft supple nature; Maxon or PDS are much to stiff and may cause irritation to the oral cavity. Hemorrhage is controlled by suture pressure. No attempt is made to cauterize or clamp bleeding vessels. When the palate excision and suturing are complete, the stay sutures are cut and the remaining soft palate replaced and evaluated once again for extent of resection. 2 and 3 Everted laryngeal saccule resection: The patient is placed in dorsal recumbancy with the mouth opened widely (see positioning). Everted laryngeal saccules appear as edematous, translucent tissue balls lying in the ventral aspect of the glottis and obscuring the vocal folds. and Surgical removal is performed using a long-handled laryngeal cup biopsy forceps (or similar long handled biopsy instrument) or a long handled Allis tissue forceps and #15 BP scalpel blade. If a laryngeal cup biopsy forcep is used the everted saccule is grasped and amputated with the biopsy forcep. Any remaining tags are grasped with a long-handled rat tooth tissue forceps and trimmed with a #15 BP blade or scissors. If an Allis tissue forceps is used the laryngeal saccule is grasped with the Allis forceps and a long-handled scalpel with a #15 BP blade is used to excise the saccule at its base. There is some suggestion that if the stenotic nares and elongated soft palate can be successuflly treated (see above), the lateral saccules will return to their normal location in the larynx and no longer cause airway obstruction without the need for surgical resection. The author no longer removes lateral saccules. If the patient had a tracheostomy tube placed prior to surgery, the saccules are easily visualized and excised as described above. If the patient has an endotracheal tube exiting the laryngeal appartus, the tube is temporarly removed while the saccules are excised. Suture material/special instruments: Malleable retractors, head lamp, long-handled laryngeal cup biopsy forceps (or similar instrument), long-handled Allis tissue forceps, long-handled scalpel handle, long-handled rat tooth forceps, 3-0 or 4-0 Dexon or Vicryl with a cutting needle. Postoperative care and assessment: Any patient requiring surgery to relieve airway obstruction should be monitored carefully (preferrably in a critical care environment) for the first 24 hours postoperatively. The degree of care may vary depending upon the patients presenting signs and surgical manipulations required to correct the airway obstruction. Examples of the authors' degree of postoperative care based on patient presentation and surgery performed are listed below: Stenotic nares only: These patients are generally held for observation 12 - 24 hrs postoperatively and discharged from the hospital the day following surgery. Soft palate resection only: Patients that present with mild clinical signs (i.e., noise, mild exercise or heat intolerance) and are bright and alert 24 hours after surgery can be discharged that day. Patients that present with moderate to severe clinical signs (i.e., severe exercise intolerance, episodes of cyanosis, syncopal attacks) are monitored in a critical care environment until signs resolve. Immediate postoperative gagging and coughing are observed in about 13% of patients. Patients requiring a tracheostomy prior to surgery, or an emergency tracheostomy, remain in a critical care environment until the tracheostomy can be removed. Combined nares, palate, saccule repair: These patients are treated similarly to patients with soft palate resection and are based on presenting clinical signs. Patients with multiple defects tend to present with moderate to severe clinical signs and may require more intensive care. Immediate postoperative gagging and coughing are observed in about 80% of patients. Patients that present with mild clinical signs (i.e., noise, mild exercise or heat intolerance) and are bright and alert 24 hours after surgery can be discharged that day. Patients that present with moderate to severe clinical signs (i.e., severe exercise intolerance, episodes of cyanosis, syncopal attacks) are monitored in a critical care environment until signs resolve. Patients requiring a tracheostomy prior to surgery, or an emergency tracheostomy, remain in a critical care environment until the tracheostomy can be removed. Prognosis: Prognosis for patients with brachycephalic syndrome is generally dependant upon the defects found at presentation. Stenotic nares only: About 96% of dogs with stenotic nares will improve postoperatively. Soft palate resection only: About 85 - 90% of dogs with soft palate resection only will improve postoperatively. Young dogs (i.e., less than 2 years of age) are more likely to improve (90%) than dogs greater than 2 years of age (70%). Stenotic nares and soft palate resection: Dogs having a combination of stenotic nares repair and soft palate resection are more likely to have a favorable outcome (96%) compared to those that did not (70%). Soft palate and everted saccule resection: Dogs having this combination of defects repaired will have an 80% chance of significant improvement postoperatively. Salivary Mucocele If you would like a copy of the illustrated version of these notes on CD and a video of this surgical procedure on DVD, go to www.ivseminars.net and click Video Vet. Key Points INTRODUCTION Salivary glands can be affected by inflammation, trauma, calculus formation and neoplasia; resulting in abscessation, rupture of the duct or gland and formation of a salivary mucocele, or obstruction and atrophy. The mode of therapy is generally dictated by the type of lesion present (abscess, mucocele, neoplasia). There are four paired salivary glands present in the dog and cat: parotid, mandibular, sublingual and zygomatic glands. The glands most commonly injured or involved in pathological processes (calculi, neoplasia, trauma) are the mandibular and sublingual salivary glands. The mandibular salivary gland is a mixed gland (serous and mucous secretion) located in the junction of the maxillary (internal maxillary) vein and lingual facial (external maxillary) vein as they form the jugular vein. It is adherent cranially to the darker, monostomatic portion of the sublingual gland, and shares a common heavy fibrous capsule with that gland. The mandibular duct leaves the medial portion of the gland near the sublingual gland, and runs craniomedially, medial to the caudal sublingual gland, between the masseter muscle and mandible laterally and the digastricus muscle medially to empty in the sublingual papilla lateral to the cranial frenulum of the tongue. The sublingual duct originates at the caudal portion of the gland and joins the mandibular duct. The secretion of the separate lobes of the monostomatic portion of the sublingual gland drain through four to six short excretory ducts into the sublingual duct. The polystomatic portion of the sublingual gland lies under the mucosa of the tongue and secretes directly into the oral cavity rather than through the main sublingual duct. Diseases of the parotid and zygomatic salivary gland occur infrequently in the dog and cat. PATHOLOGICAL PROCESSES Inflammation Infection Infection can occur in any of the salivary glands, but is a rare occurrence in the dog and cat. Sialoliths are rare in dogs and cats but may occur in patients with salivary mucocele. Included in the differential diagnosis of intermandibulare mass is intermandibular abscess. Unlike salivary mucocele, intermandibular abscess is painful in palpation, causes fever, and aspiration of the mass generally reveals puss. Sialoadenitis has been reported in the zygomatic salivary gland. Patients present with similar signs as retrobulbar abscess including pain on palpation of the mouth, reluctance to open or close the mouth, periorbital cellulitis without exophthalmos and epiphora, a fistula below the eye and/or a swelling or drainage into the mouth at the opening of the zygomatic duct. Treatment is similar to retrobulbar abscess including oral drainage near the last molar. Generally, a red inflamed area is visible. A mosquito hemostat can be used to provide ventral drainage by inserting it into the inflamed area and opening the abscess or inflamed gland. Systemic antibiotics are given for five to seven days. Parotid sialoadenitis can occur secondary to lateral ear resection if the surgeon is careless. Trauma to the parotid duct resulting in a small fistula producing serous, salivary secretion is rare in the dog and cat. If this problem occurs, treatment can be accomplished by primary anastomosis of the parotid duct or simple ductal ligation with 4 0 nylon or polypropylene suture material caudal (toward the gland) to the fistula. Appropriate wound drainage is also recommended. SALIVARY MUCOCELE Salivary mucocele formation is the most common disease of the salivary gland in the dog and cat. The mucocele is formed from secretion of saliva from a defect in the gland or duct system. The most commonly affected glands are the mandibular and sublingual, with the sublingual gland being the most frequent source of saliva. The lining of the mucocele consists of inflammatory tissue surrounded by granulation tissue. There is no evidence of a secretory lining present in the mucocele and therefore cannot be considered a true "cyst". There are three major classifications of salivary mucoceles depending upon their location: cervical mucocele, pharyngeal mucocele, and ranula. Cervical mucoceles are generally located on the lateral aspect of the head and neck from the level of the mandibular and sublingual salivary glands to the intermandibular space. The majority of patients present with mucoceles in the intermandibular region. 1 A less common location for salivary mucoceles is the pharynx. Pharyngeal mucoceles appear as a fluctuant, smooth, domed shaped swelling in the lateral pharyngeal wall. 2 Ranulas are formed from an accumulation of saliva along the base of the tongue. 3 and 4 The etiology of salivary mucoceles (cervical mucocele, pharyngeal mucocele and ranula) is generally unknown, but things such as trauma, inflammation, sialoliths, foreign bodies, and iatrogenic damage during surgery have been implicated. It is generally felt that mucoceles result from damage to the duct or gland tissue with leakage of saliva into the tissues. The monostomatic (cervical mucocele) and polystomatic (pharyngeal mucocele and ranula) portions of the sublingual salivary gland are felt to be the most commonly involved. Poodles and German shepherds are reportedly the most common breeds affected, but many breeds have been reported to have developed salivary mucoceles. Cervical Mucocele Diagnosis is based on history, physical examination, palpation 5 , and aspiration of a blood tinged saliva 6 and 7 and 8. Differential diagnosis includes cervical abscess, neoplasia, enlarged mandibular lymph nodes and draining tract secondary to foreign body migration (see example images above). Sialography may be attempted, but is time consuming and difficult with questionable results in many cases. The treatment of choice for cervical mucocele is removal of the mandibular and sublingual salivary glands and ducts on the affected side and ventral drainage of the accumulated saliva. Quite often, the patient with a cervical mucocele will present with a midline, intermandibular cervical mass making lateralization difficult. Determination of the glands involved, right side vs. left side, can be accomplished by the following methods:
Surgical technique: See the DVD for a detailed video description of the surgical technique. Removal of the mandibular and sublingual salivary glands is performed by first positioning the dog in lateral recumbency with the affected side uppermost. 6 The neck and jaw should be positioned slightly obliquely and towels or sand bags placed under the neck to elevate the surgical site for better visualization of the bifurcation of the jugular vein. The incision is made from the ramus of the mandible cranially to the bifurcation of the jugular vein caudally 7; occlusion of the jugular vein prior to incision will facilitate visualization of landmarks. 8 Dissection is carried into the capsule of the mandibular and sublingual salivary glands. 9 An intracapsular dissection commences and the glands are removed from the capsule. 0 and 1 and 2 The ducts of the mandibular and sublingual salivary glands are followed craniomedially to the mandible. 3 If you are on the correct side, you should encounter saliva from the mucocele oozing into the incision. 4 In some cases a dilation of the duct can be visualized. Aspiration of the dilated duct will produce saliva of similar color and consistency as that aspirated during diagnosis. 5 The ducts are followed as far cranially as possible and ligated or stripped out to complete the resection. 6 An incision is made at the most dependant point of the cervical mucocele (when the animal is standing!) and a penrose drain is placed to facilitate postoperative drainage of saliva. 7 Platisma muscle, subcutaneous tissues and skin are closed in a routine fashion. 8 and 9 The drain is removed two to three days postoperatively. If the salivary glandular tissue has an unusual appearance at the time of resection, it should be submitted for histopathologic evaluation. Complications: Complications associated with salivary gland resection are few, but may include:
Pharyngeal Mucocele Patients with pharyngeal mucocele may present with signs related to upper airway obstruction, since the swelling eventually becomes large enough to occlude the laryngeal orifice. Affected patients may have a history of noisy respiration progressing to intermittent dyspnea, cyanosis, and syncope in severe cases. A presumptive diagnosis can be made by careful oral examination. The pharyngeal mucocele appears as a fluctuant, smooth, dome shaped swelling in the lateral pharyngeal wall. 0 Aspiration of a blood tinged saliva is diagnostic, and is generally performed when the patient is under anesthesia to avoid unnecessary stress. Pharyngeal mucoceles can be treated several ways. Initial treatment consists of opening and draining the mucocele, partially excising the overlying pharyngeal mucosa and suturing the cut edges of the mucosa to the adjacent pharyngeal wall (marsupialization). Another technique is to dissect the mucocele free from the surrounding tissue and remove it en bloc. The pharnyngeal wall is allowed to heal by granulation. Either procedure generally gives rewarding results. Recurrence is rare, but ipsilateral, mandibular and sublingual salivary gland resection should be done if recurrence does occur (see operative description above). Ranula A ranula is a thin walled linear swelling that results from ruptured sublingual or mandibular salivary ducts below the oral mucosa next to the tongue or rupture of the polystomatic portion of the sublingual gland. 1 Rannulas have been reported in cats. 2 Diagnosis is based on history, oral examination, palpation and aspiration of the mass. Blood tinged saliva on aspiration is diagnostic. Surgical technique: See the DVD for a detailed video description of the surgical technique. Marsupialization or excision as for pharyngeal mucocele are the treatments of choice for ranulas. For marsupialization incise the rannula with a scalpel blade. 3 Next, empty the contents of the ranula. Finally, suture the mucous membrane of the ranula to the oral mucosa. 4 Use a multfilament synthetic absorbable suture of 3-0 size. An alternate technique is to incise the ranula as described above but resect it instead of marsupialize it. 5 NOTE: If recurrence occurs, or if the ranula is associated with a cervical mucocele, the mandibular and sublingual salivary glands on the affected side should be removed along with excision or marsupialization of the ranula. Prognosis The prognosis for patients with cervical, pharyngeal, ranula or a combination is favorable if the surgeon can identify the involved side and if all salivary tissue is successfully removed. Surgical Management of Abdominal Trauma General principles and techniques Definitions Celiotomy is a surgical incision into the abdominal cavity; the term laparotomy often is used synonymously, although it technically refers to a flank incision. A sudden onset of clinical signs referable to the abdominal cavity (e.g., abdominal distention, pain, vomiting) is called an acute abdomen. Preoperative Concerns Celiotomy is performed for a variety of reasons; surgery may be indicated for diagnostic purposes, such as obtaining biopsy samples, or for therapeutic reasons. Many animals that undergo abdominal exploratory surgery have chronic disease, but in some patients emergency abdominal surgery must be performed because of acute clinical signs. Some conditions are life-threatening, such as gastric dilatation- volvulus, colonic perforation, or severe hemorrhage, and appropriate therapy must be started promptly. Conditions that require surgery must be differentiated from those that can be managed medically. Although obviously unnecessary surgery must be avoided, surgery cannot always be delayed until it is certain the patient will benefit from it. The decision to operate is based on the history and physical examination findings, radiographic and ultrasonographic studies, and laboratory analyses. Physical examination can be unreliable in predicting the severity of abdominal trauma. The inaccuracy associated with examining patients with acute abdominal disease, particularly that associated with trauma, can be attributed partly to the patient's condition at the time of examination and the delayed development of clinical signs that occurs with some injuries. Depressed or lethargic animals may not show pain during abdominal palpation. Clinical signs of hemorrhage often are not apparent immediately after trauma; delays of 3 to 4 hours between injury and the development of shock and collapse are common in patients with liver or spleen lacerations. For these reasons, animals that have suffered traumatic injuries should be closely observed for at least 8 to 12 hours. In most cases life-threatening hemorrhage becomes apparent before this time. However, animals with traumatic bile peritonitis can show no overt clinical signs for several weeks. Likewise, traumatic mesenteric avulsion is seldom associated with clinical signs until peritonitis subsequently develops, usually several days after injury. Sensitive diagnostic tests such as diagnostic peritoneal lavage may help identify patients with significant abdominal trauma before overt clinical signs develop. NOTE: Be aware that overt clinical signs associated with mesenteric avulsions or rupture of the biliary tract may not become evident for 1 to 2 weeks after injury. Preoperative management of most animals undergoing exploratory laparotomy is dictated by the underlying abdominal disease. General observations include noting the animal's attitude and posture, temperature, respiratory rate and effort, and heart rate and rhythm. Auscultation, percussion, and palpation of the abdomen and a rectal examination also should be performed. Serial examinations are important to detect trends or deterioration in the patient's status. An intravenous catheter should be placed for fluid and drug administration, and blood samples should be drawn. Useful initial blood work in an animal with acute abdomen includes hematocrit, serum total protein, serum glucose concentrations, complete blood count (CBC), platelet count, and blood urea nitrogen (BUN). Other laboratory tests, such as the serum biochemistry profile and clotting parameters, can be performed, depending on the animal's condition and the suspected underlying disease. Urine may be collected by means of cystocentesis or catheterization for urinalysis. An indwelling urinary catheter may be used to quantitate urinary output if necessary. Abdominal radiographs may detect peritoneal fluid (i.e., uroabdomen, peritonitis) or abnormal accumulations of air. A recent study determined that the most common cause of peritoneal effusion in adult cats was neoplasia, whereas the most common cause in kittens was right-sided heart failure (Wright, Gompf, DeNovo, 1999). Animals with acute abdominal signs of uncertain cause should have diagnostic peritoneal lavage if radiographs are nondiagnostic. Electrolyte and hydration abnormalities should be corrected before surgery. NOTE: If you note free air in the abdominal cavity of an animal that has suffered a recent traumatic injury, consider exploratory surgery; this finding may indicate rupture or perforation of the gastrointestinal tract. Anesthetic Considerations The anesthetic management of animals with abdominal disease depends on the underlying disease. Young, healthy animals can be premedicated with an anticholinergic and opioid (i.e., oxymorphone, butorphanol, buprenorphine) and induced with thiopental, propofol, or a combination of diazepam and ketamine given intravenously to effect. Antibiotics The appropriate use of antibiotics in patients undergoing abdominal surgery depends on the underlying disease, the animal's overall general health, and the length and type of surgical procedure. Surgeries of less than 1½ to 2 hours in which a contaminated, hollow viscus is not opened do not usually warrant prophylactic antibiotics. Surgical Anatomy The rectus sheath is composed of an external and internal leaf. The external leaf is formed by the aponeurosis of the external abdominal oblique muscle and a portion of the aponeurosis of the internal abdominal oblique muscle. The aponeurosis of the transversus abdominis muscle joins the external leaf near the pubis. The internal leaf consists of a portion of the aponeurosis of the internal abdominal oblique muscle, the aponeurosis of the transversus abdominis muscle, and the transversalis fascia. The internal leaf disappears in the caudal third of the abdomen where the aponeurosis of the internal abdominal oblique muscle joins the external leaf, leaving the caudal rectus abdominis muscle covered only by a thin sheet of transversalis fascia and peritoneum. NOTE: The linea alba is easier to locate near the umbilicus because it becomes narrower near the pubis. Surgical Techniques The abdomen generally is explored by means of a ventral midline incision. In most animals the entire abdomen, including the inguinal areas, and the caudal thorax should be prepared for aseptic surgery to allow extension of the incision into the thoracic or pelvic cavities if necessary. Prepping too small an area is a common mistake, particularly for abdominal exploration in trauma patients. To visualize all abdominal structures adequately, the incision must extend from the xiphoid process to the pubis. If only a specific abdominal structure is to be examined, a shorter incision can be made. A caudal abdominal incision that extends from the umbilicus to the pubis is adequate for bladder exploration; similarly, a cranial abdominal incision (i.e., umbilicus to xiphoid process) allows evaluation of the liver and stomach. Rarely, the midline incision is extended laterally at the xiphoid process (1 cm caudal to the last rib) to facilitate exposure of the liver, biliary system, and diaphragm. A paracostal (paralumbar) celiotomy can be used to expose the kidneys and adrenal glands; it is most commonly used for unilateral adrenalectomy. NOTE: Always count surgical sponges before making the incision and before abdominal closure to help ensure that none are inadvertently left in the abdominal cavity. Ventral Midline Celiotomy in Cats and Female Dogs With the patient in dorsal recumbency, make a ventral midline skin incision beginning near the xiphoid process and extending caudally to the pubis. Sharply incise the subcutaneous tissues until the external fascia of the rectus abdominis muscle is exposed. Ligate or cauterize small subcutaneous bleeders and identify the linea alba. Tent the abdominal wall and make a sharp incision into the linea alba with a scalpel blade. Palpate the interior surface of the linea for adhesions. Use scissors to extend the incision cranially or caudally (or both) to near the extent of the skin incision. Digitally break down the attachments of one side of the falciform ligament to the body wall or excise it and remove it entirely if it interferes with visualization of cranial abdominal structures. Clamp the cranial end of the falciform ligament and ligate or cauterize bleeders before removing it. Ventral Midline Celiotomy in male Dogs With the patient in dorsal recumbency, place a towel clamp on the prepuce and clamp it to the skin on one side of the body. Drape the tip of the prepuce and clamp outside the surgical field. Make a ventral midline skin incision beginning at the xiphoid process and continuing caudally to the prepuce. Curve the incision to the left or right of the penis and prepuce (i.e., the side opposite the clamped prepuce) and extend it to the level of the pubis. Incise the subcutaneous tissues and fibers of the preputialis muscle to the level of the rectus fascia in the same plane as the skin incision. Ligate or cauterize large branches of the caudal superficial epigastric vein at the cranial aspect of the prepuce. Retract incised skin and subcutaneous tissues laterally and locate the linea alba and external fascia of the rectus abdominis muscle. Do not attempt to locate the caudal linea alba until subcutaneous tissues have been incised and the abdominal musculature fascia identified. Tent the abdominal wall and make a sharp incision into the linea alba with a scalpel blade. Palpate the interior surface of the linea for adhesions. Use scissors to extend the incision cranially or caudally (or both) to near the extent of the skin incision. Paracostal Celiotomy Position the animal in lateral recumbency and place a rolled towel or sandbag between the animal and the operating table. Make a skin incision from the ventral vertebral column to near the ventral midline. Center the incision halfway between the wing of the ilium and the last rib. Extend the incision through the external abdominal oblique muscle with scissors. Separate internal abdominal oblique and transversus abdominis muscle fibers and expose the peritoneal and transversalis fascia. Tent the peritoneum and sharply incise it with scissors. Abdominal Exploration Systematically explore the entire abdomen. Various techniques may be used; however, every surgeon should develop a consistent pattern to ensure that the entire abdominal cavity and all structures are visualized and/or palpated in each animal. Use moistened laparotomy sponges to protect tissues from drying during the procedure. If generalized infection is present or if diffuse intraoperative contamination has occurred, flush the abdomen with copious amounts of warmed, sterile saline solution. Historically, many different antiseptics (i.e., povidoneiodine, chlorhexidine) and antibiotics have been added to lavage fluids. Povidone-iodine is the most widely used antiseptic; however, this practice has not shown a beneficial effect in repeated experimental and clinical trials and may be detrimental in animals with established peritonitis because the carrier, polyvinylpyrrolidone, inhibits macrophage chemotaxis. Similarly, there is no substantial evidence that adding antibiotics to lavage fluid benefits patients treated with appropriate systemic antibiotics. Remove the lavage fluid and blood and inspect the abdominal cavity before closure to ensure that all foreign material and surgical equipment have been removed. Perform a sponge count and compare it with the preoperative count to ensure that surgical sponges have not been left in the abdominal cavity. Abdominal Wall Closure The linea alba may be closed with a simple continuous or a simple interrupted suture pattern. The simple continuous technique does not increase the risk of dehiscence when properly performed (i.e., secure knots, appropriate suture material, adequate bites in the rectus sheath), and it allows for rapid closure. Preferably strong, absorbable suture material (i.e., polydioxanone, polyglyconate, poliglecaprone 25) should be used for continuous suture patterns, and six to eight knots should be placed at each end of the incision line. Surgical gut and stainless steel wire should not be used for continuous suture patterns. On each side of the incision, incorporate 5 to 7 mm of fascia in each suture. Place abdominal wall sutures no further apart than 3 to 4 mm, depending on the animal's size. Tighten sutures sufficiently to appose but not enough to strangulate tissue, because sutures that strangulate tissue negatively affect wound healing. Incorporate full thickness bites of the abdominal wall in the sutures if the incision is midline (i.e., through the linea alba). Do not incorporate the falciform ligament between the fascial edges. If the incision is lateral to the linea alba and muscular tissue is exposed (i.e., paramedian incision), close the external rectus sheath without including muscle or peritoneum in the sutures. Close subcutaneous tissues with a simple continuous pattern of absorbable suture material and reappose the preputialis muscle fibers in the male dog. Use nonabsorbable sutures (simple interrupted or continuous appositional pattern) or stainless steel staples to close skin. Place skin sutures without tension. Healing of the Abdominal Wall The ability of tissues to hold sutures without tearing depends on the tissue's collagen density and the orientation of collagen fibrils. Skin and fascia are strong, whereas muscle and fat are weak. Peritoneum heals rapidly across the incision and does not contribute to wound strength, therefore closure of this layer is not beneficial. Experimental and clinical studies in dogs suggest that suturing peritoneum may increase the incidence of postoperative intraabdominal adhesions. NOTE: Make sure to incorporate fascia in the linea closure. Because the holding layer of abdominal incisions is collagen dense fascia rather than muscle, dehiscence is common if the rectus fascia is not incorporated in sutures. SUTURE MATERIALS AND SPECIAL INSTRUMENTS Useful instruments for celiotomy include Balfour abdominal retractors, Poole or Yankauer suction tips, malleable retractors, and Mixter (right-angle) forceps. Laparotomy pads and 4 × 4 sponges should have radiopaque markers. Postoperative Care and Assessment The abdominal incision should be checked twice daily for redness, swelling, or discharge. If the animal licks or chews at the incision, an Elizabethan collar or sidebar should be used to prevent iatrogenic suture removal. Early signs of altered wound healing are inflammation and edema. Serosanguineous drainage from the incision and swelling are consistent signs of acute incisional dehiscence. Dehiscence usually occurs 3 to 5 days after surgery, when minimal healing has occurred and the sutures have weakened; however, it may occur earlier if knots were tied improperly or if fascia was not incorporated into the sutures. Evisceration usually results in sepsis and severe blood loss secondary to mutilation of exposed intestine and must be treated promptly. The abdomen should be bandaged, fluid therapy initiated, and broad-spectrum antibiotics given while the animal is prepared for surgery. If technical failure is suspected, such as poor knot tying or improper suturing, the entire suture line should be removed and replaced. Debridement of the wound edges is unnecessary and delays wound healing. The intestine should be closely inspected for viability and damaged sections resected if appropriate. The abdominal cavity should be lavaged copiously with warmed, sterile saline. Open abdominal drainage should be considered in animals with generalized peritonitis. Wound disruption after 10 to 21 days usually results in hernia formation rather than evisceration. Hernial repair in these animals may require excision of fibrotic tissues. Subsequent closure requires that tissue layers be accurately apposed. Complications Dehiscence (incisional hernias) may occur if improper surgical technique is used (see the above discussion). The most common causes of wound dehiscence in the early postoperative period are suture breakage, knot slippage or untying, or sutures cutting through tissue. A higher rate of dehiscence may be seen in animals with wound infections, fluid or electrolyte imbalances, anemia, hypoproteinemia, metabolic disease, immunosuppression (e.g., feline immunodeficiency virus [FIV], feline leukemia virus), or abdominal distention or in those that have been treated with corticosteroids, chemotherapeutic agents, or radiation. Suture sinus formation has been reported with nonabsorbable suture material. Such cases require surgical resection of affected tissues and removal of offending sutures. Special Age Considerations Healing may be delayed in debilitated, very young or very old, or hypoproteinemic animals; chromic gut suture should not be used for abdominal wall closure in these patients. References Wright KN, Gompf RE, DeNovo RC: Peritoneal effusion in cats: 65 cases (1981-1997), J Am Vet Med Assoc 214:375, 1999. Suggested reading Brady CA et al: Severe sepsis in cats: 29 cases (1986-1998), J Am Vet Med Assoc 217:531, 2000. Hosgood G, Pechman RD, Casey HW: Suture sinus in the linea alba of two dogs, J Small Anim Pract 33:285, 1992. Wess G, Reusch C: Evaluation of five portable blood glucose meters for use in dogs, J Am Vet Med Assoc 216:203, 2000. TRAUMATIC ABDOMINAL WALL HERNIAS Definitions External abdominal hernias are defects in the external wall of the abdomen that allow protrusion of abdominal contents; internal abdominal hernias are those that occur through a ring of tissue confined within the abdomen or thorax (i.e., diaphragmatic hernia, hiatal hernia). External abdominal hernias may involve the abdominal wall anywhere other than the umbilicus, inguinal ring, femoral canal, or scrotum. Synonyms Abdominal hernias may be defined according to their location (i.e., ventral, prepubic, subcostal, hypochondral, paracostal, or lateral). The cranial pubic ligament formerly was called the prepubic tendon. General Considerations and Clinically Relevant Pathophysiology Abdominal hernias generally occur secondary to trauma, such as vehicular accidents or bite wounds; however, they occasionally have been reported as congenital lesions. Congenital cranial abdominal hernias (i.e., cranial to the umbilicus) have been reported in association with peritoneopericardial diaphragmatic hernias in dogs and cats. Abdominal hernias are false hernias because they do not contain a hernial sac. When associated with blunt trauma, they arise as a result of rupture of the wall from within caused by an increase in intraabdominal pressure while the abdominal muscles are contracted. The most common sites for traumatic abdominal hernias are the prepubic region and the flank. Cranial pubic ligament hernias often occur in association with pubic fractures. Paracostal hernias may result in migration of abdominal contents along the thoracic wall. In rare cases the abdominal contents enter the chest through defects in the intercostal muscles. Diagnosis Clinical Presentation Signalment. Most animals with abdominal hernias are young. History. A history of trauma is common with abdominal hernias. The hernia initially may be overlooked while more obvious or life-threatening injuries are treated. If strangulation or intestinal obstruction occurs, the animal may be presented for treatment of vomiting, abdominal pain, anorexia, and/or depression. Physical Examination Findings Abdominal structures (i.e., organs or omentum) in the subcutaneous space or between muscle layers usually cause asymmetry of the abdominal contour. The size of the swelling may not correspond to the size of the hernia, particularly if intestine has migrated into the hernia. The swelling should be palpated carefully to discern the contents of the hernia (i.e., intestine, bladder, or spleen) and to locate the abdominal defect. These patients should be thoroughly examined to determine whether a concurrent abdominal or thoracic injury or abnormality exists. Rupture of the cranial pubic ligament often is difficult to palpate because of subcutaneous swelling and pain. Radiography and Ultrasonography Radiographs should be taken in animals with abdominal hernias. Routine ventral dorsal and lateral views may show an associated abdominal or thoracic injury (e.g., abdominal fluid, diaphragmatic hernia). Abdominal radiographs may help confirm the presence of a hernia (i.e., subcutaneous intestinal loops and loss of the ventral abdominal stripe) when the abdominal wall defect cannot be palpated because of swelling or pain. Ultrasound scans may also help define the contents of hernias. Laboratory Findings Abnormalities associated with abdominal hernias vary depending on the severity of concurrent internal injuries. Differential Diagnosis Most hernias are diagnosed on physical examination. Differential diagnoses for abdominal swellings include abscesses, cellulitis, hematomas or seromas, and neoplasia. Medical Management Initial treatment of animals with abdominal hernias is directed toward diagnosing and treating shock and concurrent life-threatening internal injuries. Surgical Treatment Patients that sustain a traumatic injury severe enough to cause an abdominal hernia or patients that sustain penetrating abdominal wounds (i.e., gunshot, bite wounds) should have a xyphoid to pubis abdominal exploratory laparotomy. All visceral structures should be carefully examined to signs of trauma (e.g., mesenteric rents, ruptured hollow viscous organs, avulsed kidney, ureteral damage). In addition, abdominal ceiliotomy approach facilitates abdominal hernia closure. Most abdominal hernias can be repaired by suturing torn muscle edges or apposing the disrupted abdominal wall edge to the pubis, ribs, or adjacent fascia. In rare cases synthetic mesh must be used to repair the defect. Some hernias (i.e., intestinal strangulation, urinary obstruction, concurrent organ trauma) require emergency surgical correction. However, the extent of devitalized muscle may not be apparent initially, and in patients in stable condition, delaying surgery until muscle damage can be accurately assessed facilitates surgical correction. The most common complications of surgery are hernia recurrence and wound infection. Abdominal hernias that occur secondary to bite wounds usually are contaminated; wound infection and dehiscence of the skin or hernial repair (or both) may occur. Mesh should not be placed in these hernias, hernial closure is performed during exploratory laparotomy, and the skin wounds should be left open to drain. Treatment of infected wounds includes cultures, drainage, antibiotics, and/or flushing. Preoperative Management Preoperative care depends on the animal's status and concurrent injuries. Hydration and electrolyte abnormalities should be corrected before surgery. Anesthesia If there are no concurrent abdominal injuries or disease, a variety of anesthetic protocols can be used to anesthetize the animal. However, the presence of underlying disease may dictate the anesthetic management of sick or debilitated patients. Surgical Anatomy The abdominal wall is composed of four muscle layers (the external and internal abdominal oblique muscles, the rectus abdominis muscle, and the transversus abdominis muscle). Abdominal hernias may occur at insertions or attachments of these muscles or through muscle bellies themselves. The cranial pubic ligament (prepubic tendon) is a band of transverse fibers that connects the iliopectineal eminence and pectineal muscle origin of one side with those on the other side. This ligament attaches the rectus abdominis muscle to the pelvis. Positioning For ventral hernias the animal is placed in dorsal recumbency and the area around the hernia is prepared for aseptic surgery. Repair of ruptures of the cranial pubic ligament may be facilitated by placing the animal in dorsal recumbency with the rear limbs flexed and pulled cranially. Surgical Techniques Abdominal Hernias For most abdominal hernias, perform a ventral midline abdominal incision to allow the entire abdomen to be explored. Assess the extent of visceral herniation. Reduce the herniated contents and amputate or excise necrotic or devitalized tissue around the hernia. Close the muscle layers of the hernia with simple interrupted or simple continuous sutures. If a large area of devitalized tissue is removed, use synthetic mesh such as Marlex or Prolene to close the defect (do not place mesh in infected sites). Fold the edges of the mesh over and suture the folded edges to viable tissue using simple interrupted sutures. Injuries to the cranial pubic ligament can be difficult to repair. If necessary, drill holes in the pubic bone to anchor the sutures. Paracostal hernias. Make a midline abdominal incision. Explore the hernia and suture the torn edges of the transverse, internal, and external abdominal oblique muscles. Incorporate a rib in the suture if muscle has been avulsed from the costal arch. Cranial pubic ligament hernias. Make a ventral midline skin incision and identify the ruptured tendon and its pubic insertion. Evaluate the inguinal rings and vascular lacuna; these hernias may extend into the femoral region as a result of rupture of the inguinal ligament. Reattach the free edge of the abdominal wall to the cranial pubic ligament with simple interrupted sutures. As an alternative, suture the tendon remnant to the muscle fascia and periosteum covering the pubis or anchor it to the pubis by drilling holes in the pubic bone through which sutures can be placed. If the hernia extends into the femoral region, it may be necessary to suture the body wall to the medial fascia of the adductor muscles. When doing so, take care to avoid damaging the femoral vessels or nerves. Suture Materials and Special Instruments Strong, absorbable suture (polydioxanone, polyglyconate, poliglecaprone 25) or nonabsorbable suture (polypropylene or nylon) should be used to repair abdominal or ventral hernias. Marlex and Prolene synthetic mesh may be used to repair some large defects. Postoperative Care and Assessment The postoperative care of these patients is dictated by the presence of concurrent injuries or disease. The patient should be kept quiet, and the wound should be checked frequently for infection or dehiscence. Vomiting, fever, and/or leukocytosis may indicate peritonitis. Prognosis The prognosis generally is good, and recurrence is uncommon. When recurrence occurs, it generally is noted within a few days of surgery. Most animals have excellent long-term results when appropriate techniques are used. Suggested reading Waldron DR, Hedlund CS, Pechman R: Abdominal hernias in dogs and cats: a review of 24 cases, J Am Anim Hosp Assoc 22:817, 1986. PERITONITIS DEFINITION Primary generalized peritonitis refers to spontaneous inflammation of the peritoneum without any preexisting intraabdominal pathologic condition. Secondary generalized peritonitis occurs in conjunction with an intraabdominal pathologic condition and may be further classified as infectious or noninfectious. General Considerations and Clinically Relevant Pathophysiology Secondary generalized peritonitis is the predominant form of peritonitis in dogs and usually is caused by bacteria. Most cases arise through contamination from the gastrointestinal tract, often as a result of surgical wound dehiscence (Swann, Hughes, 2000). Other causes include gallbladder perforation, rupture, or necrosis; gastric or intestinal foreign bodies; intussusception; mesenteric avulsion; gastric dilatation- volvulus; necrotizing cholecystitis; pancreatic abscessation; prostatic abscesses; or foreign body penetration of the body wall. Primary generalized peritonitis occurs in cats and is associated with feline infectious peritonitis. Diagnosis Clinical Presentation Signalment. Any age, gender, or breed of dog or cat may develop peritonitis. It is particularly common in young animals that have perforating foreign bodies and in those that suffer abdominal injury, such as vehicular trauma or bite wounds. History. The history often is nonspecific. The animal may not show signs of illness for several days after the traumatic episode. Mesenteric avulsions often do not cause clinical signs of peritonitis for 5 to 7 days after the injury. Animals with traumatic bile peritonitis may be asymptomatic for several weeks after the injury. Most animals are presented for treatment of lethargy, anorexia, vomiting, diarrhea, and/or abdominal pain. NOTE: Be sure to evaluate any sick intact female dog for pyometra. Physical Examination Findings Abdominal palpation usually causes pain in affected animals. The pain may be localized, but generalized pain is more common, and the animal often tenses or "splints" the abdomen during palpation. Vomiting and diarrhea may be noted. Abdominal distension may be noted if sufficient fluid has accumulated. Pale mucous membranes, prolonged capillary refill times, and tachycardia may indicate that the animal is in shock. Dehydration and arrhythmias may also occur. Radiography and Ultrasonography The classic radiographic finding in animals with peritonitis is loss of abdominal detail with a focal or generalized "ground glass" appearance. The intestinal tract may be dilated with air or fluid or both. Free air in the abdomen may be noted with rupture of a hollow organ; it also sometimes occurs without gut rupture as a result of gasproducing anaerobes. A more localized peritonitis may occur secondary to pancreatitis and can cause the duodenum to appear fixed and elevated. Ultrasonography is useful for localizing fluid accumulation and helping to determine the etiology. Laboratory Findings The most common laboratory finding in animals with peritonitis is a marked leukocytosis; however, the neutrophil count may be normal or low in some cases. The predominant cell type is the neutrophil, and a left shift is often but not always apparent. Other abnormalities may include anemia, dehydration, and electrolyte and acid-base abnormalities. In early cases of peritonitis little or no abdominal effusion may be seen. When effusion is present, abdominocentesis should be performed and fluid retrieved for analysis. Inflammatory fluids should have an elevated number of neutrophils, which may appear degenerative. Significant numbers of leukocytes accumulate in the peritoneal cavity within 2 to 3 hours of contamination with blood, bile, urine, feces, or gastric or pancreatic secretions. Leukocyte counts in the abdominal fluid of normal dogs usually are less than 500 cells/µl. In specimens obtained by peritoneal lavage in dogs, white blood cell (WBC) counts of 1000 to 2000 cells/µl indicate mild to moderate irritation; counts over 2000 cells/µl indicate marked peritonitis (Hardie, 1995). The presence of degenerate leukocytes and bacteria in the lavage fluid also suggests intraabdominal infection. However, the presence and number of WBCs should be correlated with other clinical findings when considering abdominal exploration. Elevated leukocyte counts are found in most dogs after abdominal surgery. In animals that have undergone recent surgery, 7000 to 9000 cells/µl indicates mild to moderate peritonitis, and more than 9000 cells/µl indicates marked peritonitis (Hardie, 1995). An abdominal effusion glucose concentration below 50 mg/dl may be a specific indicator of bacterial peritonitis in dogs (Swann, Hughes, 2000). After abdominocentesis the amount of blood in the abdominal cavity can be estimated by observing the lavage sample. A red color reflects the presence of red blood cells (RBCs), and a deep red color usually indicates severe hemorrhage. If newsprint cannot be read through the plastic tubing, hemorrhage is significant; if print can be seen through the tubing, only moderate or minimal hemorrhage is present. The amount of blood in the abdominal cavity can be estimated using the equation shown below: Estimating the Amount of Blood in Abdominal Fluid The amount of blood in the abdominal cavity can be estimated using the following formula:  where: X = Amount of blood in the abdominal cavity L = Packed cell volume (PCV) of the returned lavage fluid V = Volume of lavage fluid infused into the abdominal cavity P = PCV of the peripheral blood before intravenous infusion of fluids Surgical intervention may be indicated when the packed cell volume (PCV) of lavage samples taken within 5 to 20 minutes of each other increases substantially or if an animal in shock does not respond to appropriate fluid therapy. Differential Diagnosis Advanced peritonitis with significant accumulation of abdominal fluid is not difficult to diagnose. The difficulty usually arises in determining the etiology of the effusion or infection. Early peritonitis, before the onset of overt clinical signs, is difficult to diagnose and may require diagnostic peritoneal lavage. Medical Management The goals of management of animals with peritonitis are to identify the source of peritonitis, control the source of peritonitis, lavage the peritoneal cavity, provide an efficient means of peritoneal drainage if necessary, resolve the infection, and restore normal fluid and electrolyte balances. Food should be withheld if the animal is vomiting. Intravenous fluid replacement therapy should be initiated as soon as possible, particularly if the animal is dehydrated or appears to be in shock (in dogs, 60 to 90 ml/kg/hour; in cats, 40 to 60 ml/kg/hour). Synthetic colloids such as hetastarch and dextran 70 may be beneficial, particularly if vasculitis is present. Hypokalemia and hyponatremia may be present and require intravenous supplementation. Hypoglycemia is common if the animal has septic shock (systemic inflammatory response syndrome), and glucose may need to be added to the fluids (i.e., 2.5% to 5% dextrose). Standard shock therapy should be initiated (i.e., fluid replacement and antibiotics, with or without soluble corticosteroids). If severe metabolic acidosis is present, bicarbonate therapy may be indicated. Broad-spectrum antibiotic therapy should be initiated as soon as the diagnosis is made. Escherichia coli, Clostridium spp., and Enterococcus spp. are commonly isolated from animals with peritonitis, and ampicillin plus enrofloxacin typically is an effective antimicrobial combination. However, amikacin sulfate plus clindamycin or amikacin sulfate plus metronidazole may be necessary for some anaerobic infections. A second generation cephalosporin, such as cefoxitin sodium, may also be used if gram-negative plus anaerobic infection is suspected. If renal compromise is present in an animal with a resistant bacterial infection, imipenem may be considered. The initial antibiotic therapy should be altered according to the aerobic and anaerobic culture results of lavage fluid or cultures obtained at surgery. Low-dose heparin increases survival and significantly reduces abscess formation in experimental peritonitis. The inflammatory process in peritonitis is associated with an outpouring of fibrous exudate that causes intraabdominal loculation of bacteria. The loculated bacteria are protected from host defense mechanisms and antibiotics that may not be able to penetrate the fibrin clots. Although the exact mechanism of its beneficial effect is still unknown, there appears to be little doubt that heparin is indicated in patients with severe peritonitis. Heparin may also be incubated with plasma and given to animals with disseminated intravascular coagulation (DIC). Surgical Treatment Abdominocentesis (see below) is the percutaneous removal of fluid from the abdominal cavity, usually for diagnostic purposes, although it may occasionally be therapeutic. Indications include shock without apparent cause, undiagnosed disease with signs involving the abdominal cavity, suspicion of postoperative gastrointestinal dehiscence, blunt or penetrating abdominal injuries (i.e., gunshot wounds, dog bites, vehicular injury), and undiagnosed abdominal pain. A multifenestrated catheter should be used to enhance fluid collection. Physical and radiographic examinations should precede abdominocentesis to rule out instances in which it may not be safe and to guide needle placement. Four-quadrant paracentesis may be performed if simple abdominocentesis is not successful in retrieving fluid. It is similar to simple abdominocentesis except that multiple abdominal sites are assessed by dividing the abdomen into four quadrants through the umbilicus and tapping each of these four areas. Diagnostic peritoneal lavage should be performed in animals suspected of having peritonitis if the above methods are unsuccessful in obtaining fluid for analysis. Exploratory surgery is indicated when the cause of peritonitis cannot be determined or when bowel rupture, intestinal obstruction (e.g., bowel incarceration, neoplasia), or mesenteric avulsion is suspected. Serosal patching and plication reduce the incidence of intestinal leakage, dehiscence, or repeated intussusception. Animals that require surgery and that have peritonitis secondary to intestinal trauma (disruption of mesenteric blood supply, bowel perforation, chronic intussusception, foreign body) often are hypoproteinemic. The role that protein levels play in healing intestinal incisions is not well understood. However, most surgeons are concerned that hypoproteinemic patients may not heal as quickly as patients with normal protein levels, despite one study that showed similar complication rates among animals with normal protein levels and those that were hypoproteinemic and undergoing intestinal surgery (Harvey, 1990). Most experimental evidence has shown that retardation of wound healing is not seen with moderate protein depletion but only with severe deficiencies (less than 1.5 to 2 g/dl). Although the practice of lavaging the abdominal cavity of animals with peritonitis is controversial, lavage generally is indicated with diffuse peritonitis. Lavage should be done with care in animals with localized peritonitis to avoid dissemination of infection. When lavage is performed, as much of the fluid as possible should be removed, because fluid inhibits the body's ability to fight off infection, probably by inhibiting neutrophil function. Historically, many different agents have been added to lavage fluids, especially antiseptics and antibiotics. Povidone-iodine is the most widely added antiseptic; however, its use may be contraindicated with established peritonitis. Furthermore, no beneficial effect of this agent has been shown in repeated experimental and clinical trials in animals. Although a great many antibiotics have been added to lavage fluids over the years, there is no substantial evidence that their addition is of any benefit to patients who are being treated with appropriate systemic antibiotics. Warmed sterile physiologic saline is the most appropriate lavage fluid. Open abdominal drainage (OAD) is a useful technique for managing animals with peritonitis. Reported advantages include improvement in the patient's metabolic condition secondary to improved drainage, less formation of abdominal adhesions and abscesses, and access for repeated inspection and exploration of the abdomen. With this technique the abdomen is left open, and sterile wraps are placed around the wound. The frequency of wrap changes depends on the amount of fluid drained and the amount of external soiling. Complications of open abdominal drainage include persistent fluid loss, hypoalbuminemia, weight loss, adhesion of abdominal viscera to the bandage, and contamination of the peritoneal cavity with cutaneous organisms. There is evidence to suggest the use of Jackson Pratt drains are an efficient means of draining the peritoneal cavity for 2 to 4 days post operatively. This technique allows the surgeon to perform a primary abdominal closure yet still provide abdominal drainage. Preoperative Management Animals with peritonitis that are in shock should be stabilized before surgery. Preoperative management of peritonitis is similar to that described in the previous discussion on medical management. The nutritional management of animals with peritonitis is extremely important; if the patient is debilitated, vomiting, or unlikely to resume eating for several days after surgery, enteral or parenteral hyperalimentation should be considered. Anesthesia Animals with peritonitis often are endotoxic or hypotensive or both. Small amounts of endotoxins are normally absorbed from the intestine and transported via the portal system to the liver, where they are removed and destroyed by hepatocytes. Hypotension in dogs is associated with intense portal vasoconstriction. This vasoconstriction causes breakdown of the intestinal mucosal barrier, allowing more endotoxin to be absorbed from the intestines. If hepatic function is impaired, a common condition in septic animals, small doses of endotoxin that normally would be harmless may be lethal. For these reasons, hypotension should be corrected before and prevented during and after surgery in animals with peritonitis. Animals with a total protein level under 4 g/dl or an albumin level under 1.5 g/dl may benefit from perioperative colloid administration. Colloids may be given preoperatively, intraoperatively, or postoperatively (or all three) for a total dose of 20 ml/kg/day. If colloids are given during surgery (7 to 10 ml/kg), acute intraoperative hypotension should be treated with crystalloids. Dobutamine or dopamine may be given during surgery for inotropic support. Dobutamine is less arrhythmogenic and chronotropic than dopamine and is preferred if the patient is hypotensive and anuric. If the patient is anuric and normotensive, low-dose dopamine (0.5 to 1.5 µg/kg/minute given intravenously) plus furosemide (0.2 mg/kg given intravenously) may be preferable. These patients should be monitored for arrhythmias or tachycardia. Hepatic necrosis occurs during sepsis and reduces liver function. The pathogenesis of hepatic necrosis is uncertain, but the condition may be caused by hypotension and hypoxia. Patients with hepatic necrosis may have a diminished ability to metabolize drugs, and prolonged duration of action or altered function of drugs may result. Acepromazine should not be used in animals with peritonitis if severe hepatic dysfunction is suspected. Diazepam plus an opioid is a useful premedicant in patients with hepatic dysfunction. Diazepam used alone may disinhibit some behaviors, and it should be used with caution in hypoalbuminemic patients. Most opioids have little or no adverse effect on the liver; however, morphine should not be given intravenously to dogs with hepatic dysfunction because it may cause hepatic congestion as a result of histamine release and hepatic vein spasm. Although some opioid analgesics may have prolonged action when hepatic function is reduced, their effects can be antagonized. Barbiturates (e.g., thiopental) should be used cautiously or avoided in patients with significant hepatic dysfunction. An anticholinergic may be given if the animal is bradycardic. Etomidate should be used with caution in animals with renal insufficiency, because a single induction dose of this agent has caused hemolysis in dogs and cats. The benefit of cardiovascular stability should be weighed against this risk when etomidate is used. The drug should not be used in animals with adrenal insufficiency (Pablo, Bailey, 1999). Positioning For abdominocentesis and diagnostic lavage, the abdomen should be clipped and prepared aseptically. These procedures may be performed with the animal in lateral recumbency or standing. Surgical Techniques Abdominocentesis Insert an 18- or 20-gauge, 1½ -inch plastic over-the-needle catheter (with added side holes) into the abdominal cavity at the most dependent part of the abdomen. Do not attach a syringe; instead allow the fluid to drip from the needle and collect in a sterile tube. If sufficient fluid is obtained, place it in a clot tube and an ethylenediamine tetraacetic acid (EDTA) tube, submit samples for aerobic and anaerobic culture, and make four to six smears for analysis. If fluid is not obtained, apply gentle suction using a 3-ml syringe. It is difficult to puncture bowel by this method, because mobile loops of bowel move away from the tip of the needle as it strikes them. Perforations created by a needle this size usually heal without complications. The major disadvantage of needle paracentesis is that it is insensitive to the presence of the small volumes of intraperitoneal fluid and thus a negative result can be meaningless. At least 5 to 6 ml of fluid per kilogram of body weight must be present in the abdominal cavity of dogs to obtain positive results in most cases using this technique. Diagnostic Peritoneal Lavage Make a 2-cm skin incision just caudal to the umbilicus and ligate any bleeders to avoid false positive results. Spread loose subcutaneous tissues and make a small incision in the linea alba. Hold the edges of the incision with forceps while the peritoneal lavage catheter (Stylocath) without the trocar is inserted into the abdominal cavity. Direct the catheter caudally into the pelvis. With the catheter in place, apply gentle suction. If blood or fluid cannot be aspirated, connect the catheter to a bottle of warm sterile saline and infuse 20 ml/kg of fluid into the abdominal cavity. When the calculated volume of fluid has been delivered, roll the patient gently from side to side, place the bottle on the floor, vent it, and collect the fluid by gravity drainage. Do not be surprised if you do not retrieve all of the fluid, particularly in dehydrated animals. Exploratory Laparotomy Perform a ventral midline incision from the xiphoid process to the pubis. Obtain a sample of fluid for culture and analysis. Explore and inspect the entire abdomen. Find the source of infection and correct it. Break down adhesions that may hinder drainage. Lavage the abdomen with copious amounts of warm, sterile saline if the infection is generalized. Remove as much necrotic debris and fluid as possible. Close the abdomen routinely, place an abdominal drain, or perform open abdominal drainage. Open Abdominal Drainage After completing the abdominal procedure, leave a portion of the abdominal incision (usually the most dependent portion) open to drain. Generally, make the opening just large enough to allow a gloved hand to be inserted. Close the cranial and caudal aspects of the incision with monofilament suture using a continuous suture pattern. Place a sterile laparotomy pad over the opening, then place a sterile wrap over the laparotomy pad. Change the wrap at least twice daily initially with the animal standing; sedation is seldom necessary (use sterile bandage materials and wear sterile gloves). The volume of drainage dictates the number of wrap changes needed. Break down adhesions to the incision that may interfere with drainage. Abdominal lavage may be attempted but is seldom necessary. Place a diaper over the wrap to reduce contamination from urine. Assess the fluid daily for bacterial numbers and cell morphology. When the bacterial numbers have declined and the neutrophil morphology is normal (nondegenerative), close the incision (generally in 3 to 5 days). If the opening is small, it may be left to heal by second intention. Suture Materials and Special Instruments Monofilament synthetic nonabsorbable suture (polypropylene or nylon) or slowly absorbable suture (polydioxanone or polyglyconate) should be used to close the abdomen in animals with peritonitis. Braided suture (Dacron, silk, braided nylon) or suture that may be rapidly degraded (chromic gut) should not be used. Postoperative Care and Assessment Fluid therapy should be continued postoperatively in most animals with peritonitis and is mandatory in those being managed with an open abdomen. Electrolytes, acid-base, and serum protein should be assessed in the postoperative period and corrected as necessary. Nasal oxygen may benefit septic animals. Ensuring that patients with peritonitis have an adequate caloric intake postoperatively often is difficult. An animal's energy requirement is much greater after injury or illness than at rest. Generally, the formula [30 × Weight (kg)] 1 + 70 is used to calculate a resting animal's energy requirement. Postoperatively, the metabolic rate of dogs and cats increases 25% to 35% over resting levels. With mild trauma the increase in the energy requirement is 35% to 50%; with sepsis 50% to 70% more calories are required. The factor 1.5 has been used to estimate the energy requirement of ill or injured dogs and cats. Meeting these caloric requirements in dogs with intestinal disease is particularly difficult and may require enteral or parenteral nutritional support. If hypoproteinemia becomes severe, plasma transfusions should be considered. Prognosis The prognosis for animals with generalized peritonitis is guarded; however, with proper and aggressive therapy, many survive. Some authors have suggested that the mortality rate approaches 50%. The mortality rates reported in animals with generalized peritonitis treated with open abdominal drainage have varied from 20% to 48%. References Swann H, Hughes D: Diagnosis and management of peritonitis, Emergency Surgical Practice, Vet Clin North Am Small Anim Pract 30:603, 2000. Hardie EM: Life-threatening bacterial infection, Compend Cont Educ Pract Vet 17:763, 1995. Harvey HJ: Complications of small intestinal biopsy in hypoalbuminemic patients, Vet Surg 19:289, 1990. Pablo LS, Bailey JE: Etomidate and telazol, Vet Clin North Am Small Anim Pract 29:779, 1999. Suggested reading Hauptman JG, Walshaw R, Olivier NB: Evaluation of the sensitivity and specificity of diagnostic criteria for sepsis in dogs, Vet Surg 26:393, 1997. King LG: Postoperative complications and prognostic indicators in dogs and cats with septic peritonitis: 23 cases (1989-1992), J Am Vet Med Assoc 204:407, 1994. Selected abstracts of recent manuscripts Guler O, Ugras S, Aydin M, Dilek FH, Dilek ON, Karaayvaz M. The effect of lymphatic blockage on the amount of endotoxin in portal circulation, nitric oxide synthesis, and the liver in dogs with peritonitis. Jpn J Surg 29:735 1999. This study was performed to investigate the effect of lymphatic blockage on the amount of endotoxin in portal venous blood, nitric oxide synthesis, the release of aspartate aminotransferase from the liver, hepatic damage, and survival in an experimental model of peritonitis in dogs. The animals were divided into control, unligated thoracic duct peritonitis, and ligated thoracic duct peritonitis groups. The results of this study showed that the blockage of lymph flow has a negative effect on the liver and survival in dogs with peritonitis. Jang SS, Breher JE, Dabaco LA, Hirsch DC. Organisms isolated from dogs and cats with anaerobic infections and susceptibility to selected antimicrobial agents. J Am Vet Med Assoc 210:1610, 1997. Specimens from 1267 dogs and 243 cats were studied using standard anaerobic and aerobic bacterial culture methods. Obligate anaerobic bacteria were isolated from 15.7% of the specimens from dogs and 28.4% of the specimens from cats. All of the obligate anaerobic specimens tested were susceptible to amoxicillin-clavulanic acid and chloramphenicol, and most were susceptible to metronidazole. Only 71% of the Bacteroides isolates were susceptible to ampicillin, and only 83% were susceptible to clindamycin. Only 80% of the Clostridium isolates were susceptible to clindamycin, but all were susceptible to ampicillin. Ludwig LL, McLoughlin MA, Graves TK, Crisp MS. Surgical treatment of bile peritonitis in 24 dogs and 2 cats: a retrospective study (1987 - 1994). Vet Surg 26:90, 1997. The medical records of dogs and cats surgically treated for biliary effusions at two university hospitals were reviewed. The most common causes were trauma and necrotizing cholecystitis. Determination of the bilirubin concentration of the abdominal effusion was the only diagnostic test that was 100% effective in diagnosing bile leakage before surgical intervention. The bilirubin concentration of the effusion was consistently at least two times higher than the serum bilirubin concentrations. Patients with sterile biliary effusions were found to have a much lower mortality rate than those with septic biliary effusions. Nagy KK, Perez F, Fildes JJ, Barrett J. Optimal prosthetic for acute replacement of the abdominal wall. J Trauma Injur Infect Crit Care 47:529, 1999. Sprague-Dawley rats were used to compare two prostheses for repair of acute abdominal wall defects in the presence and absence of peritonitis. Gore-Tex dual-mesh expanded polytetrafluorethylene (PTFE) and Dexon polyglycolic acid mesh (PGA) were used to cover experimentally created full thickness wall defects. Abdominal contamination was created by injecting a stool slurry intraperitoneally in some rats. At the end of 3 weeks, the rats were killed. The density of abdominal adhesions was graded, and the extent of reepithelialization was noted. PTFE was found to be superior to PGA as a replacement prosthesis for acute abdominal wall defects. PTFE was found to be associated with fewer adhesions, improved epithelialization of the wound, and less morbidity and mortality. This finding was especially true with intraperitoneal fecal soilage. Runk A, Allen SW, Mahaffey EA. Tissue reactivity to poliglecaprone 25 in the feline linea alba. Vet Surg 28:466, 1999. Poliglecaprone 25 was evaluated for tissue reactivity when used for all ligations and abdominal wall closure in routine feline ovariohysterectomies. The inflammatory reactions seen were consistent with those anticipated after implantation of suture material in a surgically created wound. There were no dehiscences in the study animals. The findings supported the clinical use of this suture material for fascial closure in cats. Shaher R, Shamir MH, Niebauer GW, Johnston DE. A possible association between acquired nontraumatic inguinal and perineal hernia in adult male dogs. Can Vet J 37:614, 1996. Previously reported cases of male dogs over the age of 4 years with nontraumatic inguinal hernias were reviewed. Nine cases were identified between 1941 and 1994, four of which also had perineal hernias. The medical records of five male dogs with nontraumatic inguinal hernias presenting to the Veterinary Teaching Hospital-Koret School of Veterinary Medicine between 1989 and 1995 were also reviewed. All five of these dogs had concurrent perineal hernias. The authors hypothesize that there is a common pathogenesis in the development of inguinal and perineal hernias in adult male dogs and suggest that every adult male dog with an inguinal hernia be carefully examined for a coexisting perineal hernia. Perivulvar Pyoderma Episioplasty (Vulvarplasty) Any plastic operation upon the pubic region or vulva can be classified as an episioplasty. The term usually refers to a specific technique used in the treatment of perivulvar pyoderma. Perivulvar pyoderma occurs most frequently in obese, usually spayed bitches (Figure 1). 
The objective of surgical treatment is to remove the redundant fold of skin and adipose tissue around the vulva which predispose the area to accumulation of moisture, irritation, and infection (tissue pinched in the surgeons fingers). The affected area is treated with cleansing and drying agents preoperatively to reduce inflammation. Surgical Technique The patient is placed in perineal position (Figure 2) and a purse string suture placed in the anus. 
Forceps are used to grasp the redundant fold of skin and retract it dorsally to help determine the amount of skin to be removed. Once this determination has been made, two inverted U shape incisions are made dorsal to the vulva (Figure 2). 
The island of excised skin is resected along with any underlying adipose tissue (Figure 4). 
The wound is closed in two layers; simple interrupted 2-0 or 3-0 synthetic absorbable suture (PDS, Maxon, Vicryl or Dexon) with a swaged on taper needle in the subcutaneous tissue and the skin with simple interrupted monofilament nonabsorbable suture (Nylon orProlene) with a swaged on cutting needle. The first suture is placed on the dorsal most point of the ventral incision and sutured to the dorsal most point of the dorsal incision Figure 3. 
The remainder of sutures are place to complete the closure. Care is taken to limit puckering of the incision between sutures by gradually taking larger bites on the dorsal incision relative to bites closer together on the ventral incision Figure 5. 
After care consists of an Elizabethan collar, anagesics, systemic antibiotics and local cleansing. The long term prognosis is excellent. Recurrence of the pyoderma is uncommon. Canine Urethral Surgery If you would like a copy of the illustrated version of these notes on CD and a video of this surgical procedure on DVD, go to www.ivseminars.net and click Video Vet. Key Points Definition: Cystic and urethral calculi have various compositions (i.e., oxalate, struvite, urate, uric acid, cystine, silicate) and may be present in the urinary bladder or lodged in the urethra, respectively. They may be multiple or single, may cause partial or complete obstruction (i.e., urethral), and may require surgical manipulation for removal. Synonyms: Bladder stones, urethral stones Diagnosis Clinical presentation: Signalment: There is no age predisposition. Dalmations are more likely to present with uric acid calculi and commonly present with calculi lodged in the urethra. Schnauzers are more likely to present with struvite calculi and Daschunds are more likely to present with cystine stones. History: Patients generally present with a history of urinary obstruction and/or signs of urinary tract infection. Common complaints include difficulty urinating, straining to urinate, hematuria, dripping blood tinged urine from the prepuce, and/or a distended abdomen. Patients that present several days after complete obstruction may have a distended and painful abdomen and a history of anuria. These patients may be so compromised that they present in shock. Clinical signs: The most frequently reported clinical signs in patients with cystic and urethral calculi include unproductive straining to urinate, blood tinged urine dripping from the prepuce, hematuria, and/or polakiuria. Severity of clinical signs may vary with the degree of urethral obstruction and duration of obstruction prior to presentation. Patients with complete obstruction for several days may show signs of post-renal azotemia (i.e., severe depression, recumbant, shocky). Physical examination: Observation in the examination room may reveal multiple unsuccessful attempts to urinate. Abdominal palpation may reveal a full urinary bladder; occasionally, calculi within the bladder may be palpable. Patients with severe clinical signs (i. e., presented several days after complete obstruction) may show azotemia, shock, and/or severe depression. Abdominal palpation generally reveals a large, turgid urinary bladder and may result in discomfort to the patient. Laboratory findings: Results of a complete blood count and serum chemistry profile are generally normal in patients presenting acutely; urinalysis may show evidence of urinary tract infection and and/or crystalluria. Patients presenting after several days of complete obstruction may have significant changes in their biochemical profile including increased BUN, increased creatine, metabolic acidosis, and severe electrolyte abnormalities. Urine is generally grossly hemorrhagic and urinalysis may show signs of urinary tract infection and crystaluria. Radiography: Survey radiographs may show presence of radiodense calculi in the urethra and/or urinary bladder as well as a distended urinary bladder. Occasionally, radiolucent calculi occur and can only be visualized using retrograde contrast cystourethrography. The most common location of urethral calculi in male dogs is immediately caudal to the os penis (see ). Careful evaluation of the kidneys and ureters should be done to rule out renal and ureteral calculi. Ultrasonographic examination of the bladder, ureters, and kidneys may be helpful in diagnosis of cystic, ureteral, or renal calculi. Differential diagnosis: Any disorder causing urinary obstruction, including urethral neoplasia, granulomatous urethritis, urethral stricture, and urethral trauma. Definitive diagnosis is based on clinical signs, inability to pass a catheter, and evidence of calculi on survey or contrast radiographs. Medical management: Immediate care: In animals with complete obstruction of a duration long enough to cause azotemia, temporary urinary diversion is provided by either passing a small urinary catheter (e.g., French) alongside the calculus, performing a prepubic cystostomy (see technique described below), or frequent cystocentesis (i.e, tid to qid). Azotemia is treated with crystalloid IV therapy prior to calculus removal. Calculus removal: Retrograde hydropulsion: See the DVD for a detailed video of this technique. This technique should result in a 90-95% success rate of retropulsing urethral calculi into the urinary bladder! Thoroughly mix 45 cc of sterile saline and 15 cc of Surgilube or KY Jelly in a 60 cc syringe and attach the syringe to the largest high density polyethylene urinary catheter that will pass through the os penis (5 to 8 French). Anesthetize the animal, extrude the penis and pass the lubricated urinary catheter in the urethra, up to and against the calculus. Place a dry gauze sponge around the extruded tip of the penis and occlude the penis around the catheter by squeezing it with thumb and finger. Using a back and forth action on the catheter, simultaneously inject the saline/lubricant mix under extreme pressure.
Surgical treatment: The objective of surgical treatment is to remove all retropulsed calculi from the urinary bladder and any remaining urethral calculi that were unable to be retropulsed. Bladder calculi are removed via cystotomy , urethral calculi are removed via urethrotomy, and patients that are frequent stone formers may benefit form a permanent urethrostomy to allow continual passage of small urethral calculi. Preoperative management: Patients that present acutely can be anesthetized immediately and retropulsion attempted (see above described technique). If urinary tract infection is suspected, preoperative treatment with antibiotics may be instituted. Patients that present after several days of complete obstruction should be treated medically until the azotemia resolves, blood gas abnormalities resolve, and electrolytes return to normal. The patients electrocardiogram should be monitered if hyperkalemia is present preoperatively. Medical treatment may consist of intravenous fluids, systemic antibiotics, continuous ECG monitoring, and bladder decompression. Bladder decompression may be accomplished via passing a small gauge urinary catheter (e.g., 5 French) past the calculus, multiple cystocentesis (i.e., tid or qid), or placement of a antepubic cystostomy tube (described in detail below). Anesthesia: Routine general anesthesia is performed in patients that present acutely without signs of azotemia. Azotemic, shocky patients with moderate to severe biochemical abnormalities should be treated as described above until these abnormalities return to normal. Surgical anatomy: The male canine penile urethra consists of urethral mucosa (i.e., urothelium) surrounded by corpus cavernosum urethra, which is in turn surrounded by tunica albuginea. Because of the fluid filled corpus cavernosum urethra (blood) and the tough fibrous connective tissue tunica albuginea, the urethra can withstand tremendous pressure (e.g., as with aggressive retropulsion) without the fear of urethral rupture. The urinary bladder consists of the following layers; serosa, muscular, submucosa and mucosa. The bladder is lined with transitional epithelium. Positioning: Patients are positioned in dorsal recumbancy for retropulsion, urethrotomy, urethrostomy, cystostomy tube placement and cystotomy. Surgical technique: The surgical techniques vary depending upon the procedure chosen, and are described in detail below: Retropulsion: The technique for retropulsion of urethral calculi is described above in medical management. Percutaneous cystostomy tube placement: Occasionally, it may be necessary to perform a percutaneous antepubic cystostomy to decompress the urinary bladder whilst treating a severely azotemic patient until they become a better anesthetic and surgical risk. The patient is sedated and placed in dorsal recumbancy. A 3-4cm incision is centered between the umbilicus and pubis. Subcutaneous tissues are disected to expose the ventral midline (i.e., linea alba). A 2-3cm incision is made in the linea alba and the bladder wall located. A 12 - 14 French Foley catheter is advanced through a skin incision 2-3 cm lateral to the abdominal incision, tunneled in the subcutaneous tissue and brought into the abdominal cavity at a location just lateral to the midline abdominal incision. A pursestring suture is placed in the bladder wall at the proposed site of Foley catheter placement with 3-0 monofilament absorbable suture. A 1cm incision is made into the bladder lumen and the Foley catheter advanced. The pursestring suture is carefully tightened to create a water-tight seal, but not to tight as to create bladder wall necrosis. The bladder wall is pexied to the abdominal wall at the point of entry of the Foley catheter with 3-0 monofilament absorbable suture in a simple interrupted pattern. The abdominal wall is closed in a routine fashion. and The cystostomy catheter is held in place with a chinese finger trap friction suture technique using #1 monofilament nonabsorbable suture and attached to a closed collection system to avoid urinary tract infection. The cystostomy tube remains in place until the patient is ready for definitive surgical treatment. Urethrotomy: The urethral calculus to be removed is located by evaluation of radiographs, palpation of the os penis and its relationship to the calculus, and/or passing a catheter in the urethra until it contacts the stone, removing the catheter and using it as a measure to locate the calculus. A 2-3 cm skin incision is made directly over the calculus. Subcutaneous tissues are dissected until the retractor penis muscle is exposed. The retractor penis muscle is dissected off the corpus cavernosum penis (it has a bluish tint from venous blood) and either moved to laterally or excised. A sharpe #15 BP scalpel blade is used to incise the urethra directly over the calculus, being careful to incise the urethra directly on its midline to help decrease cavernous sinus bleeding. No attempt is made to control cavernous sinus hemorrhage with cautery or hemostats, as this creates excessive trauma and is generally unsuccessful at controling hemorrhage. Hemorrhage is controlled with digital pressure and suction until suturing can commence. The calculus is grasped with forceps and removed from the urethra. The urethral incision can be left open to heal by second intention; if this method is chosen moderate hemorrhage can be expected for several days postoperatively. Alternately, the urethral incision can be closed in layers; urethral mucosa and tunica albuginea with 4-0 or 5-0 monofilament absorbable suture in a simple interrupted or continuous pattern, subcutaneous tissues with 3-0 monofilament absorbable suture in a simple continuous pattern and skin with 3-0 or 4-0 nonabsorbable monofilament suture. If this method is chosen over healing by second intention, postoperativ e hemorrhage will be significantly less. Use of a sutured urethrotomy is the authors technique of choice. Both urethrotomy techniques (i.e., sutureless or sutured) result in perdictable urethral healing without evidence of urethral stricture. Urethrostomy: Urethrostomy is generally performed in patients that are recurrent stone formers. It provides a permanent opening caudal to the os penis that is large enough to accommodate passage of most urethral calculi. This technique is most commonly performed in Dalmations for treatment of uric acid calculi. Scrotal urethrostomy is the location of choice for urethrostomy in dogs. It is a convienent location for surgical manipulation, this area of the urethra generally bleeds less, the urethral diameter will accommodate passage of most urethral calculi, and there is less urine scald postoperatively. Other locations for urethrostomy include prescrotal and perineal. Prior to surgery a urethral catheter (the largest size that will fit past the os penis) is passed, if possible. After a routine castration and scrotal ablation have been performed, the subcutaneous tissues are dissected to expose the retractor penis muscle. The retractor penis muscle is smooth muscle and appears light grey to cream colored. The retractor penis muscle is dissected from its attachment to the corpus cavernosum urethra. The blood filled cavernous tissue gives the urethral a bluish color. The urethral catheter is palpated and used as a firm surface to cut against when incising the urethra. Every attempt is made to incise the urethra exactly on the midline to help decrease hemorrhage. A 3 - 4 cm incision is made in the urethra. The caudal aspect of the urethral incision is positioned directly over the ishial arch. As this is the new point of urine flow it is most efficent to have urine exit before it makes a sharp turn ventrally. No attempt is made to control cavernous tissue hemorrhage with cautery or hemostatic forceps; only pressure, suction, or suture pressure should be used. After incision of the urethra, the glistening urethral mucosa is identified 4-0 or 5-0 nonabsorbable monofilament suture with a swaged on cutting or taper-cut needle is recommended by the author. The first urethrostomy suture is placed at the midpoint of either side of the urethral incision to include urethral mucosa, tunica albuginea, and skin (suture split thickness of skin). The suture is tied leaving the end without the needle 3-4 cm long to act as a stay suture. The second suture is placed directly across from the first suture and tied as described for the first. The urinary catheter can now be removed. After the first two sutures are placed, the needle end of one suture is used to begin suturing the cranial portion of the urethrostomy using a simple continuous suture pattern. When the opposite suture is encountered, the stay suture is used to tie off the first continuous suture line. The opposite suture is then used to suture the caudal portion of the urethrostomy in a similar fashion tying the final suture to the remaining stay suture. and 0 Fine ophthalmic instruments make tissue handling and suturing easier. Use of a magnifying loupe (about 2x) and head lamp light source enhances visualization of the urethral mucosa and facilitates accurate suturing. It is critical that the surgeon recognize glistening urethral mucosa and suture it to skin. This will decrease (or eliminate) the chance of urethral stricture. It has been shown that a continuous suture pattern incorporating the urethral mucosa and tunica albuginea (i.e., squeezes the cavernous tissue) results in less postoperative hemorrhage. Cystotomy: See DVD for detailed video of this technique. After successful retropulsion of urethral calculi into the bladder, the catheter used to retropulse calculi is passed into the urethra and bladder, and left in place. The catheter exiting the penis is cut. Leaving a catheter indwelled in the urethra ensures that remaining cystic calculi will not roll back into the urethra during patient transfer to the surgery suite and during patient prep. Just prior to aseptic preparation of the abdomen a soft, 10-12 French red rubber catheter or feeding tube is placed into the prepuce and a prepucal douche is performed with 180cc of a 0.01% solution of betadine. This aseptically prepares the penis and prepuce so they can remain in the surgical field throughout the cystotomy procedure. A paraperpucial incision is made from umbilicus to pubis. The prepuce is retracted and a midline celiotomy is performed. The bladder is exteriorized and examined. Stay sutures of 3-0 suture are placed in the apex and neck of the bladder. A scalpel blade is used to penetrate the ventral aspect of the bladder and enter the lumen. The ventral cystotomy incision is extended with metzenbaum scissors. The bladder should be opened from apex to neck to allow proper visualization of bladder mucosa and calculi. Stay sutures are placed on each side of the incision at its midpoint to facilitate visualization of the bladder interior. Large hemostats are placed on the stay sutures to help retract the bladder margins. A cystotomy spoon is used to scoop the bladder neck for calculi. This is performed several times. When no more calculi can be removed with the spoon, digital palpation of the bladder neck is performed to identify presence of further calculi. If further calculi are palpated further attempts are made to retrieve the calculi. Once no more calculi can be spooned or palpated, the indwelling urethral catheter placed after retropulsion is removed. Next, the largest urinary catheter that can be passed through the os penis is passed in the penile urethra to the level of the os penis (i.e., retrograde). A dry sponge is used to grasp the extruded penis to create a water tight seal around the catheter. A 60cc syringe filled with sterile saline is injected through the catheter under moderate pressure. The stay sutures on the bladder incision are retracted to enable visualization of the bladder lumen during lavage. Suction or intermittent spooning is performed during lavage in an attempt to identify and remove any remaining stones. After several lavages and negative results in obtaining stones, the catheter is placed from the bladder to the bladder neck and pelvic urethra (i.e., normograde). Lavage is once again performed in an attempt to identify and remove any remaining stones. After several lavages and negative results, the catheter is advanced until it can be seen coming out of the penile urethra. The catheter is run back and forth in the urethra several times to ensure that there are no remaining calculi (i.e., gritty feeling while passing the catheter). Finally, a piece of bladder mucosa is excised for culture and susceptability testing. The interior of the bladder is examined for urachael diverticulm 1 , masses , etc. and biopsied as necessary. The bladder wall is closed with 3-0 or 4-0 absorbable monofilament suture material using a swaged on taper or taper-cut needle in a simple continuous or simple interrupted appositional suture pattern. Only one layer closure is necessary. Abdominal closure is routine. Suture material/special instruments: Urinary catheters of various sizes, Foley catheter, head lamp light source, 2X loupes, ophthalmic instruments, 4-0 or 5-0 monofilament nonabsorbable suture material. Postoperative care and assessment: Postoperative care varies depending upon procedure performed: Percutaneous cystostomy tube: It is important to keep the percutaneous cystostomy tube attached to a closed collection device. The tube can be connected to a sterile collection bag via a sterile intravenous catheter connection set. An elizabethan collar may be necessary in some patients to prevent iatrogenic removal of the cystostomy catheter. Careful management is important to control catheter related urinary tract infection. Sutureless Urethrotomy: If urethrotomy without suturing is performed, patients must be monitored for blood loss from the urethrostomy site. Blood loss can be severe enough to lower the PCV by 2 - 3%. An Elizabethan collar may be necessary in some patients to prevent self-mutilation. Patients should be kept quiet and away from other animals (especially bitches in heat!). Tranqulization is occasionally necessary to control hyperactive or overly excitable patients. Clients should be warned that drops of blood may be present from the urethrotomy site as long as 2 weeks postoperatively. Sutured Urethrotomy: If a sutured urethrotomy is performed, patients will exhibit very little blood loss. However, an Elizabethan collar should be considered, especially in patients that may be prone to self-mutilation. Patients should be kept quiet and away from other animals (especially bitches in heat!). Tranqulization is occasionally necessary to control hyperactive or overly excitable patients. Scrotal Urethrostomy: The most common postoperative complication of scrotal urethrostomy is bleeding from the urethrostomy site. Utilization of a simple continuous suture pattern incorproating the urethral mucosa and tunica albuginea (i.e., squeezing the cavernous tissue and creating a air-tight/water-tight seal) has significantly decreased the incidence of postoperative hemorrhage in the authors opinion. An Elizabethan collar should be considered, especially in patients that may be prone to self-mutilation. Patients should be kept quiet and away from other animals (especially bitches in heat!). Over excitement immediately postoperatively can result in frank hemorrhage or subcutaneous hemorrhage. 4 Tranqulization is occasionally necessary to control hyperactive or overly excitable patients. Prognosis: The prognosis for surgical management of urethral and cystic calculi is dependant upon preoperative management of azotemic patients prior to anesthesia, success of retropulsion of urethral stones into the urinary bladder, care in removing all stones via cystotomy, and care of ensuring urethral mucosa to skin apposition during urethrostomy. Patients that have successful retropulsion of urethral calculi and do not require urethotomy or urethrostomy have a excellent prognosis. If careful attention is paid during cystotomy to ensure that no calculi are left behind (see discussion on cystotomy technique), the prognosis for cure is excellent. Long term prognosis is dependant on evaluaiton of calculus composition, dietary management, management of urinary tract infection, and attention to urine pH. Patients that require sutured or sutureless urethrotomy have a favorable prognosis if all of the remaining calculi are removed from the urinary bladder via cystotomy to ensure that no calculi are left behind (see discussion on cystotomy technique). Attention must be paid to careful lavage during cystotomy to ensure removal of all cystic calculi. Patients that have an elective urethrostomy have a favorable prognosis if attention is paid to proper surgical technique (i.e., urethral mucosa is sutured to skin). Occasionally, chronic stone forming patients will form a calculus that is to large to pass through the urethrostomy stoma. Gastrointestinal Surgery Cases Key Points Serosal patch A technique has been described for successfully treating hollow viscous organ perforation and leakage and for reinforcing areas of potential leakage. The technique involves suturing the surface of a loop of healthy bowel (generally jejunum) over the leaking or devitalized area to form a serosal patch. In the small intestine, serosal patching is most helpful when debridement and closure of an intestinal defect would result in significant lumen compromise. A typical example would be a gunshot or dog bite wound to the duodenum in the area of the pancreatic and bile duct papilla. Resection and anastomosis would be difficult due to the presence of the duct systems as well as location of pancreas. Serosal patching would allow closure of the defect, preservation of lumen diameter, preservation of pancreas, and avoidance of pancreatic and bile ducts. Serosal patching is also indicated for support of an enterotomy or intestinal anastomosis that is of questionable viability. It is effective in preventing leakage even if the anastomosis breaks down as the patch seems to retain its integrity in the face of peritonitis or protein calorie malnutrition. Use of a serosal patch may also be indicated to support enterotomy closure in patients with protein losing enteropathy undergoing full thickness, multiple intestinal biopsies. Technique: When using a serosal patch to cover a defect, the defect is first debrided to healthy bleeding margins and irrigated. A loop of jejunum is brought into apposition with the defect and sutured using a simple continuous apposing pattern of 4 0 or 5 0 polypropylene (Prolene) suture. Sutures are placed 2-3 mm apart and about 3 mm from the edge of the defect; be sure sutures are in viable bowel wall. Polypropylene suture is used for its nonreactive properties as well as its continued tensile strength in the face of peritonitis, hypoproteinemia, and prolonged illness. Sutures are placed 360° around the defect making sure to suture submucosa of both structures with each bite. Examples of serosal patching in supporting an intestinal anastomosis and enterotomy or for patching leaks in other abdominal viscera are shown in the following figures. Advantages of serosal patch over omentum include: its strong subserosal layer, it withstands higher intralumen pressures, and it holds sutures well. It may also help to "support" the anastomosis during healing. When defects in the duodenum and colon are patched with a loop of jejunum, the serosal surface becomes lined with mucosa similar to the organ repaired. Bowel viability: The first consideration when performing an intestinal anastomosis is evaluation of bowel wall viability. The success of an anastomosis is influenced by the presence of an adequate blood supply at the incised margins. Tests used to evaluate viability of the intestinal wall should satisfy several criteria; they must be readily available, inexpensive, noninjurious, simple to perform, and easily interpreted. Standard clinical criteria for assessing bowel wall viability are: color, visible peristalsis, and visible or palpable mesenteric pulsation's. These criteria alone result in an overall accuracy of 50 60%. The use of a Doppler does not significantly increase the accuracy of detecting viable vs nonviable bowel. An alternate technique used to access viability of human intestine is termed "second look". The patient is reoperated 24 - 36 hours after the original laparotomy; bowel wall is visually inspected using criteria described above. This technique may be considered in veterinary patients being treated with open peritoneal lavage (discussed previously); bowel is inspected and re-evaluated at each lavage session (i.e., generally every 24 hours). Massive bowel resection A question often asked is; "How much small bowel can I resect and still have a nutritionally functional pet?" Experimental surgical studies reveal that dogs with 75 80% of the small bowel removed usually die within 90 days of emaciation, cachexia, and massive diarrhea with undigested food in the stools when fed standard diets. However, dogs with 50 60% of the small bowel removed will eventually undergo enough intestinal villous adaptation that a nutritionally sound pet can be expected. Recently, it has been shown that dogs undergoing 75 - 80% small bowel resection (i.e, leaving 18 inches from the descending duodenum and 18 inches from the ileum in a 25 kg dog) will be nutritionally functional if given an H2 receptor blocker or other acid blocking agent (i.e., cimetidine, ranitadine, famotadine, prilosec). This is probably due to the fact that massive small bowel resection results in gastric acid hypersecretion and lipid malabsorption. The cause of gastric acid secretion is unknown (possibly increased gastrin levels), but it results in a decreased pH of the small intestine. This acid intestinal environment inhibits lipase activity and the emulsification process. The use of H2 receptor blockers improves patient response by decreasing acid production, increasing digestibility of lipids by 40%, and accelerating intestinal adaptation by increasing villous length, width, and numbers. It is recommended that patients with massive bowel resection (60% or greater) be placed on acid blocking agents. Ileocecocolic and ileocolic valve resection If bowel resection results in removal of the ileocecocolic valve (cat) or the ileocecal and cecocolic valves (dog) malabsorption syndrome and chronic diarrhea may result. These valves function to control bacterial numbers in the small and large bowel. The small bowel has a relatively low bacterial count, and the large bowel a high bacterial count. If the valve is removed in an intestinal resection (i.e., ileocecocolic intussusception), reflux of bacteria from the colon into the ileum may occur. Overgrowth of bacteria in the small intestine results in an increased deconjugation of bile acids and hydroxylation of dietary fatty acids as well as production of bacterial metabolites toxic to epithelial cells. The absorptive capacity of the epithelial cells is then decreased, resulting in malabsorption. The toxic effect on villi result in inflammation and edema causing fluid secretion into the lumen and further malabsorption resulting in chronic diarrhea Figure%2029.pdf. Treatment with intestinal antibiotics may help control the overgrown small bowel bacterial population. A similar syndrome can occur with chronic partial obstructions (i.e., mural neoplasms, chronic intussusception, intestinal stricture) that result in decreased movement of intestinal contents and subsequent overgrowth of aerobic and anaerobic bacteria; also called stagnant loop syndrome. Mesenteric Volvulus: Mesenteric volvulus is an uncommon but often fatal disorder in dogs; it is rarely diagnosed in cats. Clinical presentation is a young to middle age, male, medium sized to large breed dog (German Shepherd Dogs appear to be most commonly affected), presenting with an acutely distended and painful abdomen, hematochezia, +/- vomiting, and rapid onset of shock. The abdomen is moderately distended and tympanic. Abdominal distention occurs rapidly; generally less than 6 hours. Presumptive diagnosis is based on history, clinical presentation, physical examination, and radiographs. Abdominal radiographs reveal distended loops of small intestine suggesting obstruction or adynamic ileus. The stomach is generally not distended with air. Differential diagnosis includes GDV, intestinal obstruction, parvovirus, garbage gut, and generalized adynamic illeus. Treatment is emergency surgery. A xyphoid to pubis midline abdominal exploratory is performed. Adequate exposure is necessary to visualize and evaluate the volvulus for appropriate derotation. As in any strangulation obstruction, endotoxin is released to the systemic circulation when the vascular occlusion is relieved. Pretreatment with shock dose of polyionic isotonic fluids, glucose, broad spectrum antibiotics, and corticosteroids or flunixin meglumine are recommended. As these patients are also experiencing reperfusion injury, specific drug therapy shown to improve patient outcome should be considered (at this time no drug has been shown clinically effective in treating dogs with reperfusion injury). Intususception Intussusception is a sign not a disease. It most frequently occurs in young animals with a history of GI upset; generally secondary to parasitic infestation, parvovirus, etc. In older patients it may be associated with intestinal foreign body or GI neoplasia. Classic history is that of vomiting, diarrhea (with or without blood), and abdominal cramping or pain when lifted by the abdomen. Clinical signs are as with any gastrointestinal obstruction however, in puppies and kittens, the signs may "come and go". This is thought to be due to the effects of an intussusception that comes and goes (i.e., sliding intussusception). Physical examination generally reveals an easily movable, slightly painful, sausage-like abdominal mass. Diagnosis is based on history, clinical signs, palpation of an abdominal mass, and pain on abdominal palpation. Radiographs may reveal an obstructive pattern. and A barium enema may outline the intussusception but is rarely necessary for the diagnosis. Be appreciative of the sliding intussusception that presents with periodic signs of an abdominal mass that seems to "come and go". Treatment of intussusception in the dog and cat is generally surgical. Barium enemas rarely reduce the intussusception and maintain its reduction. Laparotomy generally reveals either an ileocecocolic, jejunal, or rarely a colonic intussusception. A thorough abdominal exploratory for multiple intussusceptions, foreign bodies, or other causes of GI obstruction should be done in all cases. When attempting to surgically reduce an intussusception, very gently push distally and pull proximally (don't pull hard). Frequently, intussusceptions can be reduced without serosal tears. Once reduced, examination of the bowel for intestinal foreign bodies, masses, etc. is performed (remember, intussusception is a sign not a disease). If the intussusception is reducible but there is questionable viability, inject fluorescein dye and make viability assessments as previously described. If no obvious abnormality exists to explain the presence of the intussusception, an enteroplication should be performed. Enteroplication: Technique. Enteroplicaiton is performed by exteriorizing the small intestine from the proximal jejunum to the ileum. The bowel is placed in an accordion like manner and sutured together to form permanent adhesions. The seromuscular/submucosal layer (do not penetrate into the lumen) of one loop of bowel is sutured to the seromuscular/submucosal layer of the adjoining bowel using simple interrupted sutures of 4 0 Vicryl, Dexon, PDS, or Maxon. The plicated bowel is replaced into the abdominal cavity and closure is routine. The planned adhesions prevent bowel from re intussuscepting. Plicated bowel remains adhered for at least two months postoperatively and no abnormal gastrointestinal signs or nutritional disturbances result. Recurrence is essentially eliminated. If reduction of the intussusception results in seromuscular tears or if bowel viability is assessed as poor, serosal patching or resection and anastomosis should be considered. Serosal patch and anastomotic techniques have previously been described. Any of the appositional techniques may be successfully used. If resection and anastomosis is performed, the resected bowel should be examined carefully to determine a possible cause. If there is no evidence of a foreign body, mass, etc., the remainder of the bowel should be plicated as described above. Postoperative treatment for patients with intussusception is as previously described for any intestinal foreign body. Rectal prolapse or prolapsed intussusception? Whenever a patient presents with a rectal prolapse, the clinician must first rule out the possibility of a prolapsed intussusception. This shows the presentation of a dog with a prolapsed rectum or a prolapsed intussusception. The differential diagnosis can easily be made by placing a finger or instrument (e.g., thermometer, forceps) between the prolapsed bowel and the anocutaneous junction. If the finger passes easily between the two structures the diagnosis is prolapsed intussusception (as in ); if resistance is met immediately the diagnosis is rectal prolapse. A schematic if this is shown in. Surgical management of megacolon in cats Clinical presentation: Megacolon is a condition in which the ascending, transverse, and descending colon are chronically large in diameter and filled with inspisated stool. Patients generally present with a history of chronic constipation (i.e., weeks to years), tenesmus, and weight loss. Males are more commonly affected than females and the age ranges from one year to 12 years. Etiology: The etiology of megacolon is either congenital, acquired, or idiopathic. The idiopathic form is the most common type seen in the cat. Diagnosis: Diagnosis of idiopathic megacolon in cats is usually made on the basis of history, abdominal palpation, and radiography. Confirmation is based on exploratory laparotomy. Treatment: The decision to operate is generally made on the basis of the constipation becoming progressively worse and responding only to multiple enemas and manual deobstipation. Exhaustive medical therapy is generally performed prior to surgical intervention. Preoperative management: Preoperative bowel preparation, using antibiotics administered orally or multiple cleansing enemas is probably useless in cases of severe constipation or obstipation. A parenterally administered antimicrobial agent, with a spectrum of activity directed toward coliforms and anaerobes, is probably the most efficacious preoperative management. Subtotal colectomy: Subtotal colectomy is the procedure of choice in cats with megacolon. This technique is performed regardless of how much of the colon appears diseased. The surgical objective is to remove all of the colon except what is necessary to reestablish bowel continuity. When the ileocecocolic valve is removed (i.e., which is done if the cecum appears grossly abnormal), a 1.5 - 2 cm segment of descending colon just proximal to the pubis (i.e., colorectal junction) is saved to accommodate the ileo-colonic anastomosis. When the ileocecocolic valve is retained, a 1 cm segment of ascending colon is preserved to accommodate the colonic anastomosis. Several techniques have been described for performing the colonic anastomosis. The author's technique of choice is an end-to-end anastomosis. The procedure is performed using a single layer simple continuous or simple interrupted appositional pattern with 3-0 or 4-0 synthetic absorbable or monofilament nonabsorbable suture. Because of lumen diameter differences between the ileum and colon, it is necessary to place several sutures in the larger diameter bowel in order to produce an even, watertight anastomosis. After the anastomosis is completed, the peritoneal cavity is thoroughly lavaged with 200 - 300 ml/kg of warm, sterile physiologic saline solution prior to closure. In situations where the anastomosis is under any question, particularly with respect to color and blood supply (i.e., tissue viability), it is advisable to place a serosal or omental patch over the anastomotic area to help prevent leak, provide a source of blood supply, and help support the anastomosis. Postoperative care: Immediately postoperatively patients should be supported with a balanced electrolyte solution intravenously until they are able to maintain their hydration status. Antimicrobial agents are continued for five to seven days in all cases. Patients are returned to their normal diet within 24 hours and are allowed water ad libitum. Results: Long term results have been somewhat variable from case to case, but generally:
Linear foreign bodies Clinical presentation: Linear foreign bodies (e.g., string, plastic bags, tinsel, tape deck tape, yarn, thread) occur in the dog and cat. The classic presentation is a patient four years of age or less with persistent vomiting, anorexia, and depression. These signs are common with many gastrointestinal disturbances and linear foreign body should be included in your differential diagnosis. Occasionally, patients are presented late in the course of the disease and may have a history of intermittent vomiting with anorexia, depression, and weight loss as the major presenting signs. Diagnosis: A thorough physical examination should be performed with emphasis on oral examination and abdominal palpation. Oral examination often reveals the linear foreign body around the base of the tongue in cats. The foreign body itself may be seen or an area of inflammation may be present at the junction of the base of the tongue and frenulum. Figure%201.pdf Abdominal palpation may reveal "bunched up" small intestine due to the plication. When this finding is made, the clinician should be very gentle with further abdominal manipulations so as not to encourage bowel perforation. Radiography: Definitive diagnosis is based on characteristic findings on survey and contrast radiography. Survey radiographs may reveal plicated bowel bunched up in one quadrant of the abdomen. Due to its plicated nature, air accumulation in the bowel lumen forms a characteristic "tapered enteric gas bubble". Three or more tapered gas bubbles are diagnostic for linear foreign body. Figure%202.pictA Evidence of peritonitis (i.e., ground glass appearance), free gas in the abdominal cavity, ileus, or the presence of a needle are findings that may be present on survey radiographs. Patients with subtle changes or questionable findings should have an upper gastrointestinal contrast study (e.g., barium 6.6 11 ml/kg). The typical plicated appearance of the bowel is diagnostic for linear foreign body. If your index of suspicion is high that perforation exists, Gastrografin (1,900 mOsm), iohexol (520 mOsm), or another water soluble contrast material should be used as barium is difficult to remove from the peritoneal cavity and is a significant irritant. Because of its low osmolality, iohexol is recommended as the water soluble contrast agent of choice in evaluation of GI disorders where barium is contraindicated. The possible disadvantage of iohexol is its cost @ $0.80/ml. Contrast dosages: Gastrografin: 1.1 2.2 ml/kg (0.5 - 1 ml/lb); Iohexol at 240 mg/iodine/ml preparation: diluted with water (1:1 or 1:2) and given at a rate of 10 ml/kg [1:1 dilution with water gives 120mgI/ml or 1:2 dilution with water gives 80 mgI/ml]. Radiographic views should be taken at 0, 30, and 60 minutes. Presurgical treatment: Surgery for the removal of linear foreign bodies should be accomplished as soon as possible. Presurgical preparation of patients diagnosed early and in good health include an intravenous catheter, maintenance fluids (22 ml/kg TID), replacement of fluid loss from vomiting and dehydration, and antibiotics prior to abdominal exploratory. Patients that present in septic shock (i.e., perforation, peritonitis, severe dehydration) should be treated with a shock dose of fluids (90 cc/kg IV), antibiotics (gentamicin and ampicillin), shock dose of steroids (2 4 mg/kg IV), and have a blood glucose level taken and fluids supplemented with 2 1/2% dextrose as needed. Electrolytes (chloride, potassium, sodium) and acid base evaluation are helpful in presurgical management. When fluid losses have been replaced and shock therapy instituted the patient is anesthetized for abdominal exploratory. Surgical treatment: After ceiliotomy, the plicated bowel is gently exteriorized from the abdominal cavity. In order for a linear foreign body to result in intestinal obstruction and clinical signs, it must be lodged somewhere in the proximal gastrointestinal tract. Common areas include: base of the tongue (i.e., string is often looped around the base of the tongue), stomach or pylorus (i.e., a ball of string is often lodged at the pylorus), or duodenum (i.e., the string becomes impacted in the descending or ascending duodenum). The surgeons first task is to locate the area in which the foreign body is lodged and release it. If it is lodged under the tongue it should be cut at the time of exploratory laparotomy; if it is lodged in the stomach or pylorus, it is released via a gastrotomy; if it is lodged in the duodenum, it is removed via enterotomy. Once the proximal end is released, the extent of the linear foreign body is evaluated, and 2 3 subsequent jejunal enterotomies are performed to remove the remainder of the foreign body. Care is taken to remove the linear foreign body in segments short enough that further cutting of the mesenteric border of the intestine does not occur during removal, yet long enough to perform a minimum number of enterotomies. These numbers and distances vary with the type and length of linear foreign body involved. The mesenteric border is examined carefully for evidence of perforation. All linear foreign bodies should be removed to the level of the ascending colon. Colotomies are not necessary, as once the linear foreign body is in the colon it can be passed with little danger of causing obstruction. An alternate technique for removal of a linear foreign body is to identify and release the obstructed proximal aspect of the foreign body and attach the released end of the linear foreign body to the flanged end of a 12 - 18 French red rubber catheter/feeding tube. Pass the blunted end of the catheter into the gastrotomy or enterotomy and pass it aborally through the entire length of the intestinal tract and out through the anus. As the catheter is passed, it pulls the linear foreign body out of the GI tract and releases the bowel from its plication. This technique eliminates the need for multiple enterotomies to remove the foreign body. Difficulty can arise when attempting to pass the catheter through the small intestine. Care should be taken not to encourage further trauma to the mesenteric border while passing the catheter. After the foreign body has been completely removed, a close examination of the mesenteric border is made for evidence of perforation. Any perforation should be debrided and sutured. If multiple perforations occur, a resection and anastomosis may be necessary. Serosal patching may be considered to protect an anastomosis or enterotomy site in a compromised patient. Serosal patching is not recommended to patch mesenteric perforations as suturing the patch may result in vascular compromise to the affected intestinal segment. Patients with multiple mesenteric perforations that cannot be sutured without severely compromising bowel viability should undergo massive bowel resection. Remember, you can successfully resect 60 - 70% of the small intestine and have a nutritionally acceptable animal. If the client is willing to treat their dog or cat with an acid blocking agent, this resection can be expanded to a 75 - 80% small intestinal resection. The abdominal cavity is lavaged with copious quantities (e.g., 200 300 ml/kg) of sterile physiologic saline solution prior to closure. Placement of a enterostomy feeding tube should be considered in severely debilitated patients. Postoperative management (i.e., fluids, antibiotics, feeding) is as previously discussed. Prognosis: Prognosis for patients with linear foreign body is directly related to the presence or absence of bowel perforation at the time of surgery. Patients without preoperative perforation have an 85% chance of survival while those with preoperative perforation have only a 50% chance of survival. This survival rate further reinforces the importance of early diagnosis and surgical treatment. Gastrointestinal neoplasia The overall incidence of gastrointestinal tract neoplasia in animals is low (16% of canine neoplasms and 28% of feline neoplasms originate in the alimentary tract). Clinical signs associated with the presence of small intestinal neoplasia vary with the location of the tumor in the bowel (i.e., high or low), the degree of obstruction (i.e., partial or complete), and the rate of growth of the tumor causing the obstruction. Intermittent vomiting and diarrhea, hyporexia to anorexia, depression, and cachexia are commonly seen with slow growing mural neoplasms that cause chronic partial obstruction. An abdominal mass may be palpable on physical examination. A presumptive diagnosis can generally be made by characteristic findings on an upper gastrointestinal contrast study (i.e., barium). Definitive diagnosis requires abdominal exploration and intestinal biopsy (generally excisional biopsy). Leiomyosarcoma in dogs Leiomhosarcoma is a slow-growing, malignant tumor of smooth muscle origin. It is the second most common intestinal tumor in dogs. Dogs with leiomyosarcoma of the small intestine have no breed or sex predilection and present at a median age of 10 years (range, 8 - 15 years). Clinical signs include vomiting, lethargy, anorexia, and diarrhea. Occasionally, patients present with weight loss and distended abdomen. Radiology reveals an abdominal mass in 60% of cases. Jejunum is the most common site in the small intestine and duodenum is second. If surgical resection and anastomosis is feasible, median survival can be expected to be 1.1 year (range, 7 months to 5.3 years). Prognosis in dogs treated surgically for leiomyosarcoma of the small intestine is favorable to excellent. Intestinal adenocarcinoma in the cat This tumor most often affects older male Siamese cats (11 years old is the mean). Presentation is often nonspecific and includes weight loss, depression, intermittent vomiting and diarrhea, and hyporexia to anorexia. Clinical signs may last from a few days to several months. Tumors are most commonly found in the jejunum, ileum, and ileocecal colic region (i.e., rarely colonic). Diagnosis is often made by performing an upper GI barium series. and At laparotomy, they appear as pale annular strictures affecting 1 5 cm segments of the intestine. and They are firm on palpation and may be associated with a pre- and post-stenotic dilatation of the intestinal tract. Treatment includes wide excision of the tumor. Since most recurrences are at the previous anastomotic site, it is recommended that 5 7 cm of grossly normal intestine be included on each end of the resection. Remember, 60 to 70% of the small intestine can safely be resected in the dog and cat. A routine intestinal anastomosis as previously described is performed. Resection or incisional biopsy of a regional mesenteric lymph node should be performed and submitted with the intestine for histopathologic evaluation and tumor staging. It is important that the pathologist read the "margins" of the intestinal resection as well as the tumor and regional lymph node. This may help determine the appropriate prognosis. Postsurgical survival time varies from 5 28 months. Survival times may increase if wider resections are accomplished at laparotomy. Intestinal adenocarcinoma in the dog presents in a similar fashion as in the cat. Surgical therapy is similar, as is prognosis. This tumor is relatively rare in the dog as compared to the cat. Closure of the peritoneal cavity in patients with peritonitis Prior to abdominal closure, especially in cases with peritonitis secondary to intestinal perforation, the peritoneal cavity should be lavaged with copious quantities (200-300 ml/kg body weight) of sterile physiologic saline solution. The use of rubber drains for postoperative drainage and/or lavage of the peritoneal cavity is a controversial subject among surgeons. Several types of drains can be used, the most common include Penrose drains, single lumen fenestrated tubes, and double or triple lumen sump drains. 51 Although these drains may be efficient for the first 12-24 hours, omentum quickly and effectively seals them off, precluding further drainage. Jackson Pratt drains offer a more efficient means of post operative peritoneal drainage. These drains should be placed in the crania abdomen between the liver and diaphragm. Large dogs (>40 lbs) should have a second drain placed in the caudal abdomen. Drains should always be exited from the abdomen at a point distant from the midline abdominal incision. Abdominal wall closure is generally performed using absorbable or nonabsorbable monofilament suture material in a simple continuous pattern. An alternative technique for treating patients with generalized suppurative peritonitis is termed open peritoneal drainage and intermittent lavage. |
