Tips for surgical success
• Use of magnification will ensure correct identification of tissue layers . I recommend 3.5x , wide field .
• Use of delicate suture and proper instrumentation will improve the success rate in urethrostomies . Gentle tissue handling is necessary , as trauma to the mucosa will cause necrosis and dehiscence . The most common cause of stricture after perineal urethrostomy is failure to adequately dissect the ischiourethralis muscles from the pelvis and failure to correctly appose mucousa-to-skin . Tensionfree anastomosis must be achieved
• Place sutures from inside to out
• Stents may be used to encourage healing of partial defects or to prevent urine from contacting the incision during initial healing
• Primary revision of the original stoma is the treatment of choice for failed perineal urethrostomy .
• Continuous pattern with absorbable suture In one study , a minor modification of the technique was described that involves applying two continuous suture patterns with absorbable suture material ( polydioxanone ). 1 This modification allows for decreased operative time , minimizes the volume of suture material in the wound and obviates the need for suture removal , which can often require sedation . No strictures or dehiscences were noted in the 18 cases that were reported , and the overall complication rate was similar to previous reports .
• Positioning and approach . Perineal urethrostomy can also be performed with the cat positioned in dorsal recumbency . This is a major advantage in cats with bladder stones , allowing simultaneous cystotomy and perineal urethrostomy without repositioning . To facilitate exposure of the perineum , the pelvic limbs are pulled forward and secured to the table . Although this technique is no more difficult than a perineal approach , it does require a bit of practice before you are comfortable with it .
• Postoperative care pointers An Elizabethan collar must be placed before recovery from anesthesia , as immediate self-trauma is a common cause of immediate incisional dehiscence . Analgesia with a long-acting opioid such as buprenorphine can be combined with a single perioperative dose of a nonsteroidal anti-inflammatory drug in cats that show no evidence of renal dysfunction due to obstructive uropathy .
Cover the wound with petroleum jelly to minimize urine scald . Removing clots that form on the incision is discouraged as this will cause additional trauma to both the cat and the incision .
Maintenance of a urinary catheter can be considered to bridge the incisions until a fibrin seal is achieved . Some surgeons avoid using urinary catheters because of concerns that the catheter may cause trauma to the incision line and increase the risk of stricture formation .
Intravenous antibiotics ( cefazolin ) are administered at the time of induction but are typically discontinued after surgery unless indicated by specific culture and sensitivity results .
Recheck urine cultures are indicated every six to 12 months because of an increased risk for ascending urinary tract infections .
• Complications Despite the widespread success of perineal urethrostomy in accomplishing patent urinary diversion in cats , a number of complications have been reported , including stricture of the urethrostomy , subcutaneous urine leakage in the perineal region , haemorrhage , urinary tract infection and incontinence . 2 Although some of these complications can be managed conservatively , many require surgical revision to restore urinary function . Thus , almost since the inception of the perineal urethrostomy procedure , there has been a need for revision methods .
• Revision techniques Prepubic urethrostomy . One of the original methods for salvage of failed perineal urethrostomy surgery is prepubic urethrostomy , which involves transecting the urethra and transposing the stoma to a caudal abdominal location , cranial to the pubis . Unfortunately , subsequent experience with this technique showed a high rate of postoperative complications , including urinary incontinence ( six of 16 cats ) and urine scalding ( seven of 16 cats ). 3 Six cats were euthanased within
Issue 02 | APRIL 2017 | 11