|
Soft Tissue Surgery Howard B. Seim III, DVM, DACVS College of Veterinary Medicine Colorado State University, Fort Collins Colorado Abdominal Exploratory; biopsy, biopsy, biopsy Key Points
The systematic, thorough observation and palpation of all abdominal structures are mandatory with any exploratory. It is easy to miss a second intestinal foreign body or an area of metastasis if one does not get in the habit of complete exploratory. This can be done in any order but it is best to establish a routine and follow it for every exploration. With experience it can be done in less than five minutes. The best way to recognize an abnormal finding is to know the normal. Take advantage of any laparotomy to observe normal structure, color, consistency and position of all abdominal organs. Abdominal exploratory may be indicated in following situations: Preoperative Considerations A midline abdominal celiotomy (xiphoid to pubis) is the easiest and most versatile approach. Positioning the patient's head toward the top of the table and tilting the table at a 30° to 40° angle will facilitate gravitation of abdominal viscera out of the thorax. Rarely is it necessary to extend the incision into the thorax via a median sternotomy however if you index of suspicion is high that this may be necessary (e.g., diaphragmatic hernia, chylothorax, porosystemic shunt) the animal should be properly and adequately prepared. Abdominal Exploratory Technique Position, Preparation and Draping The abdomen is always clipped and prepared wider and longer (lengthwise most important) than you may anticipate for a "routine" procedure (Fig. 1a). This generally means from cranial to the xyphoid to a point 2-3 cm caudal to the brim of the pubis and laterally to the ventral lumbar musculature. The animal is placed in dorsal recumbency with front and hind limbs secured with ropes to the table. If the penis or prepuce does not need to be accessible during surgery, the prepuce is clipped but not flushed. Standard skin preparation is performed. The surgeon then clamps the prepuce to the side using a sterile towel clamp. When the animal is draped in, the prepuce is not included in the surgical field. The exception to this rule is when the surgeon feels it is necessary to pass a urinary catheter during surgery. An example of this situation is urethral and cystic calculi. In this case, the prepuce is clipped then flushed using dilute Betadine or chlorhexidine prior to the prep. A ventral midline incision (Fig. 1b) is made from xyphoid to pubis. After identifying the linea alba (the linea alba is palpable at the umbilicus), a scalpel blade is used to open the abdominal cavity via a stab incision (Fig. 1c). Mayo scissors are used to complete the abdominal incision (Fig. 1d). Make sure that you can see or feel the internal side of the linea so that you do not damage abdominal viscera during this procedure. The falciform ligament is excised with scissors from its attachment to the midline. This will allow better inspection of viscera and facilitate easier closure of the abdomen (Fig. 1e, f). Moistened laparotomy sponges should be placed on the incision if viscera are to be brought out of the abdomen. All viscera must be kept moist with saline solution. Examination of abdominal viscera can be done in any order but it is best to establish a routine and follow it every time the abdomen is explored. Generally, start with proximal GI tract and move distally, then liver and pancreas, then urinary tract. Be thorough, and always be gentle when handling tissue. it is easy to miss a second intestinal foreign body or an area of metastasis if one does not get in the habit of performing a complete exploratory. With experience, complete exploration can be performed in less than five minutes. The best way to recognize an abnormal finding is to know the normal. Take advantage of any laparotomy to observe normal structure, color, consistency and position all of abdominal organs. You should be able to identify the following structures:
The linea alba is closed with monofilament absorbable or nonabsorbable suture using a simple continuous pattern. If the abdominal incision was made directly on the midline (i.e., linea alba) closure requires full thickness bites of the linea alba. If the abdominal incision was slightly off the midline, closure of the rectus sheath only (do not include rectus abdominus muscle or peritoneum). The most important tissue in the abdominal closure is the external rectus sheath. Incorporation of the internal sheath (i.e., peritoneum) is unnecessary as the peritoneum has no holding power and may actually increase adhesion formation. The suture should be placed approximately 5 mm on either side of the incision line. Subcutaneous tissues are closed separately with a simple continuous pattern using monofilament absorbable or nonabdorbable suture. Tissues should be approximated and not strangulated. Skin is closed with simple interrupted monofilament nonabsorbable suture. Postoperative Care Postsurgical care may include systemic antibiotics, appropriate pain medication, careful monitoring of the patient's breathing, temperature, and color. Cats should be kept on a warming device for at least 24 hours. Analgesics may be used to relieve patient discomfort, however care should be taken to monitor the effects of various analgesic drugs on respiratory effort. Summary Successful repair of a diaphragmatic hernia depends on careful preoperative and postoperative care of the patient. During the surgical repair, the surgeon must work quickly and effectively to complete the procedure as efficiently as possible. Biopsy Techniques For Abdominal Organs Liver Liver biopsy is indicated when ever an abdominal exploratory is being performed in patients thought to have liver disease or in cases that liver disease was not the primary reason for exploratory but the liver appears grossly normal. Surgical Technique Liver Biopsy. Liver biopsy is one of the most important diagnostic aids available for evaluation of liver disease. Samples for cytologic examination may be obtained via percutaneous needle biopsy, laparoscopy, or exploratory laparotomy. Percutaneous needle biopsy techniques are the most efficient in terms of time and expense. Several techniques are available for obtaining liver specimens during exploratory laparotomy. The simplest method is performed by cutting a strip of liver parenchyma 5 to 6 mm thick along the border of the liver lobe. Excessive bleeding is rarely a problem with this technique; hemorrhage is controlled via cautery or direct pressure. Diffuse liver disease must be present if this method is to be diagnostic. A second technique involves placing an encircling ligature around a pedicle of liver tissue. As the ligature is tightened, it cuts through the hepatic parenchyma, ligating hepatic vessels and bile ducts. This technique is, widely known as the Gillatine technique, has been criticized for leaving excessive amounts of devitalized parenchyma. This can be avoided by inserting scissors through the cut parenchyma and cutting hepatic vessels and bile ducts just distal to the ligature. This method requires the presence of diffuse liver disease to obtain a diagnostic biopsy unless the lesion is present in the distal aspect of the liver lobe. More localized abnormalities can be biopsied by wedge resections or partial lobectomy. Wedge resections may be performed by placing a row of overlapping, full-thickness, interrupted mattress sutures of 0 or 2-0 Maxon along each side of the wedge to be removed; these sutures should commence at the edge of the liver lobe and meet proximally to form a "V". The sutures should be tied so as to compress the liver slightly but not cut into liver parenchyma. The wedge of tissue to be removed is incised about 5 mm from the suture line. Alternatively, the wedge may be removed prior to tightening the mattress sutures; preplaced mattress sutures are then gently tied with enough tension to control bleeding. Wedge resection may also be performed utilizing the finger fracture technique (described in the section on partial liver lobectomy). The advantage of this method is the minimal amount of potentially devitalized liver parenchyma left behind. An alternate technique for use in patients with diffuse fibrotic liver disorders is performed by penetrating the affected liver lobe with a straight mosquito hemostat. The hemostat tip is placed on the surface of the liver lobe to be biopsied and gently plunged through the liver lobe until the tip of the hemostat is seen penetrating through the opposite side of the liver. The jaws of the hemostat are opened just wide enough to accept a piece of 2-0 or 3-0 Maxon suture. The Maxon is doubled on itself, the loop is passed into the jaws of the hemostats, and the loop pulled through the liver lobe. The exiting loop is cut leaving two strands of suture coursing through the liver lobe. Each strand is tied individually to "cut" through the liver. A "V" wedge is cut through the liver when both strands of suture have been tied. A number 15 BP scalpel blade is used to cut the V-shaped liver biopsy wedge from the sutures. Pancreas The old wives tale of "don't touch the pancreas" needs to be put to rest. Gentle manipulation and biopsy of the pancreas is a predictably successful procedure with almost no incidence of postoperative pancreatitis. Pancreatic biopsy Biopsy of the pancreas is performed in a similar manner as biopsy of the liver. In patients that have diffuse pancreatic disease, a segment of the right or left limb of the pancreas is identified. An encircling ligature of 3-0 Maxon is placed around the pedicle. As the ligature is tightened, it cuts through the pancreatic parenchyma, ligating vessels and pancreatic ducts. The distal pedicle of pancreas is carefully removed with a number 15 BP scalpel blade or metzenbaum scissors. Care is taken to avoid cutting the suture. If a relatively large portion of pancreas is to be removed (e.g., removal of insulinoma), a similar technique is used. In this situation, 2-0 or 3-0 monofilament nonabsorbable suture should be used. Stomach and Small Intestine Patients with chronic vomiting or chronic diarrhea of unknown origin often require gastric and intestinal biopsies for definitive diagnosis. In many cases, the surgeon will examine the gastrointestinal tract carefully and conclude that there are no apparent abnormalities. In this situation, ALWAYS perform gastric and multiple intestinal biopsies (i.e., duodenum, jejunum, ileum). Remember these words of wisdom when concluding that you have a negative exploratory laparotomy "your eyes are NOT microscopes". Gastric biopsy The stomach should be visually examined for any obvious abnormalities on the serosal surface. In addition, the stomach should be carefully palpated to determine if there are mural or mucosal abnormalities present. In the case of an observed or palpated abnormality, the surgeon should plan the gastric biopsy to include a portion of the abnormal stomach, the margin of normal and abnormal stomach, and normal stomach. Full thickness biopsies should always be taken. In the case of diffuse disease or if an abnormality cannot be located, a 3-4 cm incision should be made in the ventral aspect of the stomach equidistant from the greater and lesser curvature. Stay sutures are placed at the midpoint of the incisied edges and the interior of the stomach visually and digitally examined. If a mucosal abnormality is detected, the area should be biopsied either from inside the stomach of from the serosal surface directly over the lesion. All gastric wall incisions (e.g., biopsy, gastrotomy, partial gastrectomy) should be closed with a single layer, simple continuous or simple interrupted suture pattern being careful to get full thickness bites. Sutures should be placed no further apart than 3 mm and at least a 4 mm bite of gastric wall is recommended. Monofilament absorbable suture with a sharp taper or taper-cut (penetrating point) needle is the authors' preference. Small intestinal biopsy Several techniques can be used to successfully biopsy the intestine. Always remember; FULL THICKNESS biopsy is mandatory for the pathologist to give you the the most accurate diagnosis. The authors' preferred technique for intestinal biopsy is to make a 2-3 mm long incision on the antimesenteric border of the intestinal segment. A #11 or #15 BP scalpel blade is used to penetrate the intestinal wall. The blade is withdrawn to create a 2-3 mm long incision. A second parallel incision is made 1 - 2 mm from the original incision. A DeBakey forcep is used to grasp one end of the parallel incisions, a Metzenbaum scissor is used to cut out the piece of intestine. The surgeon should be careful not to crush the specimen with forceps. Only handle one end of the specimen whilst excision the biopsy specimen. If excessive trauma is created during biopsy, the pathologist may not be able to determine if the pathology is real or surgically created. The excised piece of intestine is examined closely to ensure that all layers have been included in the specimen. The biopsy site is closed using a simple interrupted or simple continuous suture pattern. 3-0 or 4-0 monofilament absorbable suture with a swaged-on sharp taper or taper-cut (penetrating point) needle is recommended. Care is taken to ensure that at least 3 mm bites are taken into the intestine and the sutures are no more that 3 mm apart. Biopsy of the duodenum, jejunum, and ileum is recommended whenever a chronic vomiting/diarrhea patient is explored. Complications associated with multiple intestinal biopsies are rare. Even patients that present with protein loosing enteropathy. One study looking at the complication rate of intestinal surgical procedures in patients with normal protein levels and patients that were hypoproteinemic found no difference. Complications in patients undergoing intestinal surgica procedures are generally related to the surgeons technical ability not the patients preoperative status. Prostate Gland Patients with chronic prostatic disease unresponsive to medical therapy may benefit from abdominal exploratory and prostatic biopsy. Biopsy specimens may be taken for histopathology, culture and susceptibility testing, and impression cytology. Prostatic biopsy Proper exposure of the prostate gland requires that the caudal abdominal incision go to the level of the pubis. Exposure of the prostate gland is further facilitated by placing a stay suture to the apex of the urinary bladder allowing the surgeon to apply traction to the lower urinary tract. Most dogs with prostatic disease have an accumulation of paraprostatic fat making visualization of the prostate gland difficult. This fat is disected from the prostate gland beginning at the midline and retracting the fat laterally in both directions. This exposes the ventral surface of the prostate gland. The prostate gland is visually inspected as well as carefully palpated for any abnormalities. If an abnormality is detected, biopsy should include abnormal tissue, marginal tissue, and normal tissue. If the abnormality is diffuse, the biopsy can be taken from any location. When planning the biopsy, keep in mind that the urethra travels through the middle of the prostate gland and should be avoided. If there is any doubt about its location at surgery, pass a large bore (i.e., 7 - 8 French) urethral catheter. This will enable palpation and localization of the urethra prior to biopsy. As a general rule, biopsy the vental aspect of the prostate gland just of the midline to the right or left side. Biopsy technique: The location for prostatic biopsy should be determined based on criteria described above. Preplace a deep horizontal mattress suture of 2-0 or 3-0 monofilament nonabsorbable suture material with a swaged-on taper needle. This suture placement should encompass the proposed biopsy site. Using a #11 or #15 BP scalpel blade, carefully cut a fusiform wedge out of the proposed biopsy site. Handle the biopsy specimen carefully with DeBakey forceps so as not to create pathology with traumatic handling. Elevate the specimen from the biopsy site and simultaneously tighten the mattress suture until hemorrhage slows down. Care is taken not to tighten the mattress suture so much as to tear through the prostatic tissue. If a small amount of hemorrhage persists, gentle pressure for 2 minutes by the clock will generally resolve the problem. Occasionally, omentum may be necessary to encourge hemostasis; several pexy sutures can be used to keep the omentum in place. Principles of Gastrointestinal Surgery Key Points
Patient stress: The stress of anesthesia and surgery inhibit leukocyte activity and immune response of the patient. Pathogenicity of the organism: In small bowel obstruction, the pathogenicity and relative invasiveness of the organism is dependent upon the character of the obstruction. Bacteria sequestered in a strangulated loop of bowel are much more likely to reach the systemic circulation than bacteria moving through a partial obstruction. Moreover, sequestered bacteria are likely to be much more virulent and have an increased lethal effect on the patient. Tissue susceptibility: Antibiotics are indicated when significant tissue damage is present or anticipated and when hypovolemic or septic shock exists. Surgical time: If surgical time is expected to be greater than 90 minutes, prophylactic antibiotic therapy should be considered. Criteria for Use of Prophylactic or Therapeutic Antibiotics Prophylactic antibiotics should be considered in the following situations:
Absorbable suture: Maxon and PDS. PDS and Maxon, are synthetic absorbable monofilament suture materials with similar properties to that of Dexon and Vicryl. They were developed to overcome the problem of tissue drag and knot slipping found in the braided synthetic absorbables. They have been shown to retain approximately 70% of their tensile strength at 3 4 weeks, and are absorbed by hydrolysis (unaffected by infection, contamination, hypoproteinemia). These suture materials are ideal for use in gastrointestinal surgery. Possible disadvantages include stiffness and a tendency to kink. These are the author's absorbable sutures of choice for gastrointestinal surgery. Nonabsorbable suture: Nylon, Polypropylene, Polybutester. Monofilament, nonabsorbables are excellent suture materials for use in contaminated or infected surgical sites. They have a high tensile strength, are relatively inert in tissue, noncapillary, and do not act as a nidus for infection. These materials pass through tissue with essentially no tissue drag and have excellent knot tying security at sizes 3 0 to 5 0. For their properties, effectiveness, and cost, these are the author's nonabsorbable sutures of choice for intestinal anastomosis and enterotomy closure. Possible disadvantage of these materials is their memory. Suture size: For the majority of small intestinal surgical procedures in dogs, 3 0 or 4 0 size suture material is adequate; in cats, size 4-0 or 5-0 is recommended. Needles: Swaged-on "atraumatic" reversed cutting, narrow taper point, or fine taper cut needles are recommended for gastrointestinal surgery. Suture Placement: When suturing intestine, sutures should be placed 3 4 mm from the cut edge of the intestine and 3 4 mm apart. It is important to recognize the everted mucosa and be sure the 3 - 4 mm bite is not in mucosa but in the submucosal layer. Suture Pattern; Appositional*: Anatomic apposition of individual layers of the bowel wall (i.e., mucosa, submucosa, muscularis, and serosa) result in primary intestinal healing. This technique is superior to inverting or everting techniques because apposition of intestinal margins eliminates lumen compromise. Primary intestinal healing results in direct bridging of the collagen laden submucosal layer (holding layer) with rapid restoration of the villous epithelium and an undisturbed vascular pattern in the anastomotic area. Two suture patterns result in an appositional closure: simple interrupted apposing, simple continuous apposing, and simple interrupted crushing. 1) Simple interrupted apposing. This technique involves suturing all layers of the intestinal wall and tying the knots on top of the serosa to approximate cut edges. The sutures should be tied tight enough to effect a watertight seal, yet not so tight as to blanch the tissue and cause ischemia of intestinal margins. This technique is simple, fast, reliable, and does not result in lumen compromise. 2) Simple continuous apposing. This technique is similar to the simple interrupted appositional technique however, a continuous suture pattern is used rather than an interrupted pattern . Advantages include faster anastomosis, equal suture tension over the entire anastomosis, watertight seal afforded by the continuous pattern, and mucosal eversion is minimized. Disadvantages include the anastomosis is held by one knot and if the suture fails anywhere along the anastomosis the entire suture line will loosen. Enterotomy: An enterotomy incision may be necessary for removal of intraluminal intestinal foreign bodies (e.g., balls, rocks, toys, linear foreign bodies), intestinal biopsy, exploration of the bile duct papilla or intestinal lumen, or rarely intestinal decompression. The segment of bowel to be incised should be removed from the abdominal cavity and packed off with moistened laparotomy pads. An incision parallel to the long axis of the bowel (i.e., longitudinal) or perpendicular to the long axis of the bowel (i.e., transverse) may be made on the antimesenteric border, preferably in healthy bowel (i.e., the aboral side of the foreign body). The ability of a relatively small enterotomy incision to accommodate a large foreign body allows the surgeon to deliver the foreign body through a relatively small enterotomy incision. Closure is performed using any of the appositional techniques previously described (i.e., simple continuous or simple interrupted). When full thickness biopsy of the small bowel is indicated (i.e., duodenum, jejunum, ileum) a small, yet representative sample, should be excised. The enterotomy incision can be either longitudinal (as for foreign body removal described above) or transverse. For diagnostic accuracy, it is important that all layers of the intestinal wall (i.e., serosa, muscularis, submucosa, and mucosa) be included in the biopsy specimen. Enterotomy closure is performed as described above (i.e., simple continuous or simple interrupted apposing). Transverse closure: If a large full thickness piece of intestine must be excised (i.e., mural mass), longitudinal closure may result in stenosis. To prevent this, transverse closure of the linear incision is recommended. This ensures adequate lumen diameter without the need for intestinal anastomosis. Omentum can be placed over the enterotomy, but need not be sutured. A serosal patch (discussed later) may be considered in bowel with questionable viability. Intestinal anastomosis: Intestinal anastomosis is indicated for resection of nonreducible intussusception, necrotic bowel wall secondary to complete intestinal obstruction, intestinal volvulus, stricture secondary to trauma, and intestinal neoplasia (e.g., leiomyoma, leiomyosarcoma, adenocarcinoma). After a complete abdominal exploration, the affected length of bowel is delivered from the peritoneal cavity and isolated with the use of moistened laparotomy pads. If possible, the intestinal anastomosis should be performed on a water resistant surface (e.g., plastic drape, crib sheet) to prevent strike through contamination. Once the level of resection has been determined, the appropriate mesenteric vessels are ligated, and the portion of intestine to be resected is isolated by clamping the bowel at a 60° angle away from the mesenteric border. This angle ensures adequate blood supply to the antimesenteric border. Bowel lumen diameters: In cases where the oral end of the bowel is dilated and the aboral end is of normal size(i.e., distal end), several options exist to create intestinal lumens of equal diameter:
The following tips may prove helpful when performing an intestinal anastomosis:
Postoperative care Intravenous fluids to maintain hydration and ensure renal function are continued postoperatively, until the patient begins to eat and drink. Intravenous fluids should then be tapered over a 24 to 48 hour period. Systemic antibiotics are continued postoperatively for 5 7 days; 10 - 14 days in cases with peritonitis and/or sepsis. Feeding: Feeding the postoperative gastrointestinal surgical patient must be based on the following criteria:
The most common postoperative complication of small intestinal surgery is leakage; leak is either associated with breakdown of the anastomosis or improper surgical technique (i.e., improper suture placement, inappropriate suture material, knot failure, sutures to far apart, inappropriate bite in the collagen laden submucosal layer, suturing nonviable bowel). A presumptive diagnosis may be accomplished by the following:
Surgical Management of GI Cases Key Points
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. 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. A barium enema may outline the intussusception but is rarely necessary for the diagnosis. Be appreciative of the sliding intus-susception 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 ileo-cecocolic, 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 can easily be done 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; if resistance is met immediately the diagnosis is rectal prolapse. 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. 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. 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) or banamine (in dogs only @ 1 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 surgery. 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. 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. Colonic surgery should be avoided whenever possible. 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. 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. Although this work has not been studied in cats, it is presumed to be similar. 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. 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. 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. Although these drains may be efficient for the first 12-24 hours, omentum quickly and effectively seals them off, precluding further drainage. Patients with generalized suppurative peritonitis should be treated with open peritoneal drainage and intermittent lavage. Abdominal wall closure is generally performed using absorbable or nonabsorbable monofilament suture material in a simple continuous pattern. Open peritoneal lavage Generalized peritonitis occurs frequently in small animal practice. The major causes include bacterial, chemical, and miscellaneous (i.e. neoplasia, parasitic, secondary to foreign bodies). Generalized peritonitis secondary to gastrointestinal disorders may also occur. This is commonly a result of perforated bowel from penetrating trauma, iatrogenic contamination at the time of surgery, an ischemic bowel segment secondary to torsion or volvulus, or breakdown of a previous intestinal procedure (e.g., anastomosis or enterotomy). In each instance, bacterial contamination and subsequent infection lead to generalized suppurative peritonitis. Appropriate therapy for patients with generalized peritonitis of any etiology includes careful preoperative, operative, and postoperative planning. Prior to operative intervention, the patient should be stabilized; this generally involves appropriate therapy for septic shock (i.e., fluids, broad spectrum antibiotics, glucose, nonsteroidal antiinflammatories, steroids). After proper medications have been given, and a shock dose of fluids administered, the patient is considered "stabilized", is anesthetized and prepared for aseptic surgery. Wide exposure through a ventral midline abdominal incision from xiphoid to pubis will allow thorough exploration of the abdominal cavity. Samples of peritoneal fluid are taken for cytology and culture and susceptibility testing. All visceral adhesions and fluid-filled pockets are carefully broken down using sharp and blunt dissection to allow proper drainage of purulent material. Careful examination of all visceral structures is performed in order to find the source of contamination. Any GI perforations are debrided and repaired with monofilament nonabsorbable suture (Prolene, Nylon, Novafil) or synthetic absorbable suture (PDS, Maxon, Vicryl, Dexon). Following appropriate exploration and surgical repair, peritoneal lavage with copious quantities (i.e., 200-300 ml/kg body weight) of body temperature sterile physiologic saline solution is performed. The lavage encourages mechanical removal of purulent material, dilution of bacterial numbers, and dilution of endotoxins. The question of continued postoperative drainage in patients with severe generalized peritonitis has always been controversial. It is virtually impossible to "drain" the entire peritoneal cavity with any soft rubber drain tube (i.e., Penrose, tube, sump), yet closure of a contaminated or infected cavity is contraindicated. It has recently been shown that open peritoneal drainage and intermittent lavage in patients with generalized peritonitis doubles the chance of survival. It is therefore recommended to "leave the abdomen open" to allow appropriate drainage. One of the major problems associated with this procedure is patient cooperation. The following technique has resulted in the best patient tolerance and drainage efficiency in the author's experience.
Closure of the abdominal incision is dictated by cytologic evaluation at each lavage. As the PMN's become healthy and bacterial numbers decrease (i.e., approaching a serosanguinous exudate) abdominal closure is considered. Generally, if a positive response to therapy is going to occur, it will be seen by the second or third lavage session. Patients requiring open peritoneal lavage beyond 4 or 5 days often develop complications such as anemia, electrolyte abnormalities, and hypoproteinemia. These complications coupled with generalized peritonitis often result in an unfavorable to grave prognosis. If routine abdominal closure can be performed by day 4 or 5, the prognosis is guarded to favorable. In conclusion, patients with severe generalized peritonitis should be treated with appropriate lavage and drainage in the immediate postoperative period. It has been found that open peritoneal drainage and intermittent lavage results in an increased recovery rate for patients with generalized peritonitis. Anal Sacculectomy; A Novel Approach Key Points
Anatomy: The location and function of the following anatomic structures should be reviewed prior to medical and surgical management of diseases of the anus and rectum: internal and external anal sphincter muscle, anal sac and duct, circumanal glands, caudal rectal artery, vein and nerve, and columnar zone of the anus. These structures are commonly involved in many of the disease processes discussed below and their preservation or removal plays an important part in the patient's ultimate recovery. The Anal Sphincter Muscle (From the introduction of a report on hemorrhoidectomy written by WC Bornemeier and published in Am J of Proc, Feb, 1960.): "The prime objective of a hemorrhoidectomy is to remove the offending varicosity with as little damage as possible to the patient. Of all the structures in the area, one stands out as the king. You can damage, deform, ruin, remove, abuse, amputate, maim, or mutilate every structure in and around the anus except one. That structure is the sphincter ani. There is not a muscle or structure in the body that has a more keenly developed sense of alertness and ability to accommodate itself to varying situations. It is like the goalie in hockey...always alert." "They say man has succeeded where the animals fail because of the clever use of his hands yet, when compared to the hands, the sphincter ani is far superior. If you place into your cupped hands a mixture of fluid, solid, and gas and then, through an opening at the bottom, try to let only the gas escape, you will fail. Yet the sphincter ani can do it. The sphincter apparently can differentiate between solid, fluid, and gas. It apparently can tell whether its owner is alone or with someone, whether standing up or sitting down, whether its owner has his pants on or off. No other muscle in the body is such a protector of the dignity of man, yet so ready to come to his relief. A muscle like this is worth protecting." Physiology: The rectum has little importance in digestion, and acts as a reservoir or collecting tube for undigested waste. The most important physiologic function of the rectum and anus is in the controlled act of defecation (i.e., continence). Clinical Signs: Common clinical signs associated with diseases of the anus and rectum include: dyschezia, hematochezia, tenesmus, anal licking, ribbon-like stools, matting of anal hair, anal discharge, scooting, excessive flatulence and diarrhea. Patients that present with any of the above clinical signs should have a thorough physical examination with emphasis on the anorectal region, including a digital rectal examination. Physical Examination: A complete physical examination should be performed in all patients with clinical signs specific for anorectal disease in order to rule-out systemic disorders that manifest themselves with anorectal abnormalities (i.e., pemphigus). Specific examination of the anorectal region should include close visual examination of the perineum, circumanal area, and base of the tail, as well as careful digital rectal palpation. In many instances this may be all that is necessary to obtain a definitive diagnosis. If a more detailed examination is needed, the use of an anal dilator or proctoscope may be indicated. These techniques require heavy sedation or general anesthesia to adequately perform. Epidural anesthesia has proven to be an effective anesthetic regime for examination of the anus and rectum. Excellent muscle relaxation allows easy anal sphincter dilation and visualization of the anal canal and rectal mucosa. The patient is placed in a perineal position for examination. Sphincter muscle atonia or areflexia: This form of incontinence occurs when the peripheral nervous supply to the external anal sphincter muscle or the muscle itself has been partially or totally severed. The external anal sphincter muscle is made up of striated muscle fibers, and is partially responsible for the voluntary control of defecation. Isolated injury of the pudendal nerve to the external anal sphincter is uncommon, but may occur from iatrogenic causes. Injury can occur during the following surgical procedures:
Anal Sacculitis: Anal sac impaction and abscessation is the most common anorectal disorder diagnosed by the small animal practitioner. Diagnosis is confirmed by clinical signs, visual and digital rectal examination. Relief of impaction by digitally expressing the anal sacs is easily performed during rectal examination. If abscessation is present, infusion of an antibiotic preparation may be sufficient to eliminate the infection. Systemic antimicrobial treatment may be required in resistant cases. If abscessation becomes a chronic recurrent problem, surgical excision of both anal sacs is the treatment of choice. Surgery should be delayed however until the immediate infection or abscess has been controlled medically as described above. There are two techniques used to successfully remove anal sacs. The first technique is illustrated in. A pair of Metzenbaum scissors is used to cut into the anal sac through the duct. The sac is opened to expose the glistening interior lining of the sac. Hemostats are used to grasp the full thickness of the sac wall, being careful to preserve external anal sphincter muscle. A number 15 BP blade is used to carefully scrape the gland from the underlying external anal sphincter muscle. The external anal sphincter m., subcutaneous tissue and skin are closed with a synthetic absorbable suture material in a simple interrupted pattern. This technique is preferred by the author as it allows visualization of the anal sac during excision. Regardless of the procedure used, if the entire anal sac is removed, the prognosis is excellent. Foley Catheter Technique A novel approach to removing anal sacs utilizes a 6 French Foley catheter placed into the anal sac through the anal sac orifice. Once introduced into the sac, the Foley catheter bulb is inflated with 1-2 cc of saline. The bulb distends the anal sac making identification and palpation of the gland simple. The protruding catheter allows the surgeon, or the surgeon's assistant, to place gentle traction on the gland during dissection. A 360-degree skin incision is made around the protruding catheter. Metzenbaum scissors are used to dissect to the level of the anal sac wall. Identification of the wall is made by the grayish color of the wall in comparison to the red color of external anal sphincter muscle fibers being dissected off of the wall. As the dissection progresses constant traction is placed on the Foley catheter to excentuate to sac. Disection is continued until the sac is completely disected free from its surrounding tissue. The external anal sphincter muscle is sutured with 3-0 Maxon and the skin closed with 3-0 nylon. This is the authors preferred technique for anal sacculectomy. Management of Cystic and Urethral Calculi in Male Dogs Key Points
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. 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., 5 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: 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. a) During injection, the calculi and urethra are lubricated by the saline/lubricant mix while the viscosity of the mixture (i.e., KY jelly and saline) encourages the calculus to dislodge and become retropulsed into the urinary bladder. b) This technique is attempted, and generally successful, regardless of how many stones are in the urethra and no matter where they are lodged. If the above technique fails, place a finger in the rectum, palpate the urethra and occlude its lumen (this dialates the urethra); repeat the above maneuvers and when maximum pressure is exerted on the urethra by the saline/lubricant mix (i.e., the urethral is maximally dialated), suddenly release digital urethral occlusion allowing lodged calculi to flush into the urinary bladder. 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. 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. 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: 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, 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!). 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. Management of Feline Cystic/Urethral Calculi Key Points
Diagnosis Clinical presentation: Signalment: There is no age, sex or breed predisposition. 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, blood tinged urine in the litter pan, 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 seen in the litter pan, 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: 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. 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 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: This technique should result in a 80-85% success rate of retropulsing urethral calculi into the urinary bladder! Thoroughly mix 20 cc of sterile saline and 5 cc of Surgilube or KY Jelly in a 35 cc syringe and attach the syringe to a 3.5 - 5.0 French soft rubber catheter. 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 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 feline 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, 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 2-3 cm 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. 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. Urethrostomy: Urethrostomy is generally performed in patients that are recurrent stone formers. It provides a permanent opening that is large enough to accommodate passage of most urethral calculi/crystals and mucoid debris. Perineal urethrostomy is the location of choice for urethrostomy in cats. It is a convienent location for surgical manipulation, the urethral diameter will accommodate passage of most urethral calculi, and there is less urine scald postoperatively. Prior to surgery a urethral catheter is passed, if possible. After a routine castration, the subcutaneous tissues are dissected to expose penile urethra. The penile urethra is disected free from surrounding connective tissue. The ventral attachment of the pelvic urethral to the pubis (i.e., ishiocavernosus m.) is identified and transected. The penile urethra is freed from its connective tissue attachments to the pelvic floor using blunt digital disceciton. The retractor penis muscle is identified on the dorsal aspect of the penis, disected from its attachment on the penis and used to develop a dorsal plane of disection to separate the pelvic urethra from its dorsal connective tissue attachments. Once the urethra is disected enough to visualize the dorsolaterally located bulbourethral glands, penile disection can stop. The penis is catheterized and the urethral orifice identified. An incision is made from the penile urethra to the pelvic urethral to the level of the bulbourethral glands. The urethral orifice at the level of the bulbourethral glands is generally large enough diameter to accept the flange of a tomcat catheter. After incision of the urethra, the glistening urethral mucosa is identified. 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 at the dorsal aspect of the urethrotomy incision on the right or left side at a 45o angle to include urethral mucosa 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 oposite the first suture and tied as described for the first. A third urethrostomy suture is placed directly on the dorsal midline to hold the dorsal margin of urethral mucosa to skin. Alternating sutures from dorsal to ventral are placed until approximately one half of the penile urethra has been sutured to skin. The remainder of the penis is amputated and the subcutanious tissue and skin are closed routinely. 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: 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. The patient is place in dorsal recumbancy with the hind legs tied gently cranially. Just prior to aseptic preparation of the abdomen a soft, 5-8 French red rubber catheter or feeding tube is placed into the prepuce and a prepucal douche is performed with 120 cc 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 caudal midline incision is made from umbilicus to pubis. 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, a 3.5 - 5 French urethral catheter is placed in the penile urethra (i.e., retrograde). A dry sponge is used to grasp the extruded penis to create a water tight seal around the catheter. A 35cc 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, 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. Perineal Urethrostomy: 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. 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 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 have an elective perineal 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. Split-shot wound management Key Points
Applied Anatomy: Skin is made up of several layers that collectively form a complex organ system. Skin is not capable of regeneration. One method of getting 'more' skin for wound coverage is encouraging local skin to undergo intussusceptive growth. This can be accomplished by applying tension to local skin around the wound. If tension is constant, skin layers will accommodate the increase tension by becoming thinner thus allowing the skin to 'stretch'. Anesthesia: Patients undergoing split-shot wound management should be placed under general anesthesia. Technique: Positioning: Patients are positioned with the wounded area uppermost. Patient preparation: Wounds identified for split-shot wound management should be treated as an open wound until there is evidence of a healthy granulation tissue bed. Routine aseptic preparation of the local skin is performed. Special instruments and suture: Metalic split-shot (i.e., other than lead) can be purchased at any local sporting goods or fishing store. Split-shots are placed in a cold sterilization media for an appropriate time period and thoroughly rinsed prior to use. Monofilament nonabsorbable suture with a swaged-on taper needle, size 00 to #1 depending upon location and size of wound is recommended. A sterile rubber bumper is fashioned from a feeding tube or catheter. Split-shot technique: The wound and surrounding skin are prepared for aseptic surgery. Two bumpers are created by cutting one 1/2 inch piece off the flanged end of a 20 French feeding tube or catheter. This segment of tube is then split in two. An appropriate size monofilament nonabsorbable suture is selected. The skin edges are gently undermined being careful not to trim the wound edge. The swaged-on needle is placed through the rubber bumper and enters the wound at the commisure. The wound edges are then sutured using a simple continuous pattern. Care is taken to engage the needle in the tough collagen laden subcutaneous tissue. Patients with thin subcutaneous tissue (i.e., cats, small dogs, areas of thin skin) may require penetration of skin instead of subcutaneous tissue. Once the entire length of the wound has been sutured, the suture is passed out through the skin of the remaining commisure of the wound. Knots are not tied in either end of the suture. Gentle traction is placed on the exiting ends of the suture until mild tension is placed on the wound edges and local skin. A split-shot is placed on each end of the exiting suture against the bumper. The split-shot is then gently but firmly clamped against the suture; this maintains tension on the skin edges and local skin. The wound is bandaged, an Elizabethan collar placed, and the patient confined to a cage. Each day the bandage is removed, the ends of the suture gently pulled and a split-shot is placed between the bumper and the original split-shot. Daily tension is performed without the need for general anesthesia or sedation. Skin may be responsive to tension for 7 to 10 days. When the wound is closed to your satisfaction, the suture and bumpers are removed. The remaining wound is bandaged only if it requires further protection. |
