Preservation of striated-muscle urethral sphincter function with use of a surgical technique for perineal urethrostomy in cats

It has been reported that perineal urethrostomy resulted in impairment of striated-muscle urethral sphincter function in male cats, as measured by urethral pressure profilometry and electromyography (EMG). Our study was undertaken to describe and evaluate a surgical technique for perineal urethrostomy that reduces trauma to the urethral branches of the pudendal nerve. Perineal urethrostomy was performed on 10 healthy neutered cats after demonstrating that they had normal urethral sphincter function by urethral pressure profilometry (maximal urethral closure pressure [MUCP] = 151 +/- 52 cm of water) and EMG activity at the level of the striated-muscle sphincter before surgery. All cats had normal urethral sphincter function 1 week (MUCP = 194 +/- 19 cm of water, EMG activity present) and 3 weeks (MUCP greater than 200 cm of water, EMG activity present) after surgery. These results indicated that preservation of the urethral branches of the pudendal nerve during urethrostomy preserved striated-muscle urethral sphincter function.     

Perineal urethrostomy versus dietary management in prevention of recurrent lower urinary tract disease

The frequency and cause of recurrent lower urinary tract disease was compared prospectively in three groups of 10 male cats during a one year period following correction of obstructive urethropathy caused by matrix-crystalline plugs. One group of cats was managed by perineal urethrostomy, one group with a calculolytic diet, and the third group by perineal urethrostomy and the calculolytic diet. Ten episodes of bacterial urinary tract infection developed in five of 10 cats with perineal urethrostomies; six episodes of bacterial urinary tract infection developed in four of 10 cats with perineal urethrostomies and consuming the calculolytic diet. Bacterial urinary tract infections were not observed in cats managed only with the calculolytic diet. Staphylococcal-induced struvite urocystoliths developed in two cats with perineal urethrostomies. Vesicourachal diverticula detected in nine cats at the time of diagnosis of urethral obstruction healed spontaneously following restoration of urethral patency and remission of clinical signs. Transient microscopic haematuria was observed in approximately 25 per cent of the cats in all three treatment groups during the one year study. Results of this study confirm the effectiveness of dietary management in prevention of recurrent urethral obstruction caused by struvite-containing urethral precipitates, and verify that recurrent signs of lower urinary tract disease in cats may be caused by agents that are different from those that initiate the problem. They also confirm that perineal urethrostomies predispose cats to recurrent ascending bacterial urinary tract infections.     

Surgical revision of the urethral stoma following perineal urethrostomy in 11 cats: (1998-2004)

Eleven cats required urethral stoma revision because of urethral stricture following perineal urethrostomy. At surgery, eight cats had evidence of inadequate dissection to the bulbourethral glands, and three cats had evidence of urine extravasation into the subcutaneous tissues. Following revision of the stoma, long-term follow-up was obtained in nine cases. For eight cats, owners reported no complications after the revision. Failure to dissect beyond the bulbourethral glands and inadequate mucosa-to-skin apposition resulted in postoperative stricture formation. Stoma revisions were performed a median of 71 days following the initial perineal urethrostomy, indicating that long-term evaluation of cases is necessary.     

Catheter-induced urethral trauma in cats with urethral obstruction

Fifteen cats were evaluated with urethral obstruction. Penile trauma by catheterization was the major indication for perineal urethrostomy. Ten cats had developed a urethral stricture and five had rupture of the urethra following medical management. All cats had abnormalities in penis and/or prepuce and/or scrotal sacs including hyperemia or swelling. Perineal urethrostomy was performed in all cases and they were evaluated for 6 months after surgery. Few complications were noted. Urinary tract infection was the most frequent complication observed. The clients considered their cats to have a good quality of life following surgery.     

Surgical procedure and postoperative management of a perineal urethrostomy in a chimpanzee (Pan troglodytes).

A chimpanzee (Pan troglodytes) with traumatic loss of the distal penis developed a gradually enlarging ventral urethral swelling and progressive dysuria. Endoscopy identified a urethral diverticulum, and endoscopic resection of the diverticulum wall was performed. Postoperative infection caused extensive necrosis of the penis, which necessitated a perineal urethrostomy. Complications of the urethrostomy included urethral obstruction from recurrent urethral stricture. The stricture was managed by regular dilatation using urethral bougies. Because of considerable postoperative swelling, catheterization was required to allow micturition following both the diverticular resection and polyp debulking. A shortened catheter sutured to the skin was tolerated for up to 10 days. Four yr after the urethrostomy, the animal is healthy and asymptomatic with endoscopic examinations performed at 12 mo intervals. This case demonstrates that with appropriate aftercare, perineal urethrostomy is an effective technique in the treatment of chronic distal urethral obstruction in the chimpanzee and probably other primate species.     

Urodynamic Evaluation of Lower Urinary Tract Function in Cats After Perineal Urethrostomy with Minimal and Extensive Dissection

Perineal urethrostomy was performed in five male cats with minimal, sharp intrapelvic transection of the ischiocavernous and ischiourethralis muscles and ventral penile ligaments, and in five male cats with extensive blunt intrapelvic dissection and sharp muscle transection. Urethral pressure profiles and cystometrograms with simultaneous fine wire electrode sphincter electromyography were performed in sedated cats before surgery and on days 14 and 28. Premicturition pressure, urethral opening pressure, maximum detrusor pressure, total volume infused, and residual volume were measured during cystometry, and maximal urethral closure pressure was measured during profilometry. A grading of (+), (++), or ( ) was used to represent the intensity of electromyographic activity. There was no difference between minimal and extensive dissection for any cystometrogram or profile variable at days 14 or 28. Urethral opening pressure and maximal detrusor pressure during cystometrography were higher in preoperative studies than after minimal or extensive dissection. Sphincter electromyography after surgery was not significantly different from preoperative results in either surgical group. The results of this study indicate that neither sharp nor blunt intrapelvic dissection significantly alters the postoperative urodynamic status in male cats.     

Urethrotomy and urethrostomy in the dog

An incision, or urethrotomy, is made into the urethral lumen to remove or relieve an obstruction temporarily. When permanent diversion of urine flow proximal to an obstructed, severely damaged, or diseased urethra is required, a urethrostomy is performed. Urethrostomy is also performed to diminish the risk of urethral obstruction due to recurrent urinary calculi that are not likely to be resolved with medical therapy. Whenever possible, to reduce the risk of urethral stricture or recurrent urinary tract infection, urethral surgery is avoided when an obstruction can be relieved by retrohydropropulsion or catheterization. Urethrotomy can be performed in the prescrotal or perineal regions depending on the level of the urethral obstruction. Although urethrostomy can be made in the perineal and antepubic positions, scrotal urethrostomy is the procedure of choice provided the lesion is distal to this area. Specific urethrotomy and urethrostomy procedures are described, including discussion about selection of the appropriate procedure for the urethral problem, patient stabilization considerations, general postoperative management, and risk of complications.     

Prepubic urethrostomy: A long-term study in 16 cats

OBJECTIVE: To investigate the indications for and long-term outcome of prepubic urethrostomy (PPU) in the cat. STUDY DESIGN: Retrospective survey. ANIMALS: Sixteen cats that had undergone PPU. METHODS: Data were recovered from the medical records of the cats. Follow-up information was obtained from the owners and referring veterinarians. RESULTS: Indications for PPU were: failed perineal urethrostomy for the management of idiopathic lower urinary tract disease (ILUTD) (8 cats) or urethral trauma (1 cat); unresolved pelvic urethral obstruction after recurrent ILUTD (5 cats); and stenosis of the pelvic urethra as a result of trauma (2 cats). A patent urethral stoma was created in all cases. Signs of lower urinary tract disease were present in 8 cats postoperatively. With appropriate dietary management, these signs resolved in 2 cats and improved in another 4 cats. Eleven cats experienced postoperative complications that consisted of peristomal skin irritation or necrosis (7 cats) and urinary incontinence (6 cats). Complications developed in the immediate postoperative period in 6 cats, and resolved in 2 of these. Six cats developed late complications, at 6 to 84 months postoperatively. Six cats were euthanatized between 1 and 26 months' postoperatively. The mean survival time in these cats was 13 months. Reasons for euthanasia included urinary incontinence (3 cats), skin necrosis (2 cats), and unresolvable ILUTD (1 cat). CONCLUSIONS: PPU is a salvage procedure that is successful in relieving the signs of urinary tract obstruction and preventing further obstruction. However, potential complications should limit its use to cases in which standard techniques for perineal urethrostomy cannot be performed. CLINICAL RELEVANCE: PPU is a comparatively simple procedure that should be considered as a salvage technique for obstructive disease of the pelvic urethra.     

Retrospective study of indications for and outcome of perineal urethrostomy in cats

OBJECTIVES: To evaluate indications for and outcome of perineal urethrostomy in cats. METHODS: The medical records of 59 cats that had undergone perineal urethrostomy were evaluated. Short-term follow up information (for a period of four weeks following surgery) was available for all of the cats. Long-term follow up information (for a period of at least four months) was available for 39 cats. RESULTS: Early complications occurred in 25.4 per cent of cats and late complications were observed in 28.2 per cent of cats. The most frequent late complication was recurring bacterial urinary tract Infection. CLINICAL SIGNIFICANCE: Despite frequent complications and recurring signs of lower urinary tract disease, 32.2 per cent of the cats had a disease-free long-term outcome (mean four years, median 3.9 years), and 88.6 per cent of clients interviewed thought that their cats had a good quality of life after surgery.     

Relationship of Lower Urinary Tract Signs to Seropositivity for Feline Immunodeficiency Virus in Cats

A group of 41 cats with signs of lower urinary tract disease was compared to a group of 41 cats without any history of disease for prevalence of seropositivity for feline immunodeficiency virus (FIV). The group of healthy cats was similar in age and gender to the group of cats with signs of lower urinary tract disease. Three of the cats with lower urinary tract disease and one control cat were seropositive for FIV.
This difference was not statistically significant. The most common cause of lower urinary tract signs was idiopathic. Only 7 cats had urinary tract infection, most associated with perineal urethrostomy or catheterization. Six of the cats with bacterial urinary tract infections were FIV negative. J Vet Intern Med 1996;10:34–38. Copyright © 1996 by the American College of Veterinary Internal Medicine .     

Modified perineal urethrostomy using preputial mucosa in cats

A modified perineal urethrostomy was performed in 14 males cats with partial or complete urethral obstruction. Follow-up information was available for 2 to 18 months. By use of this method, the preputial tissues were preserved, and the penile urethra was anastomosed to the preputial mucosa to enlarge and lengthen the urethra. Urine flow was reestablished in all cats without evidence of urethral stenosis or other major complications. Appearance of the perineal region and prepuce was not substantially altered.     

A simple continuous pattern using absorbable suture for perineal urethrostomy in the cat: 18 cases (2000-2002)

Closure with a simple continuous pattern using absorbable suture was evaluated in 18 cats that underwent perineal urethrostomy from 2000 to 2002. The perineal urethrostomy was performed in a similar manner in all the cats, and either 4-0 or 5-0 polydioxanone was used for closure. Cats were evaluated 2 weeks postoperatively, and long-term follow-up information was reviewed. In all cats, the perineal urethrostomy site was healed within 2 weeks. None of the cats developed a stricture postoperatively. Complications were not significantly different (P>0.50) from those found in a comparison group of 21 cats operated between 1997 and 2002, in which perineal urethrostomies were performed using nonabsorbable sutures that were removed postoperatively.     

Use of fluoroscopically guided percutaneous antegrade urethral catheterization for the treatment of urethral obstruction in male cats: 9 cases (2000-2009)

Objective-To describe the technique and determine outcome for male cats with urethral obstruction treated with fluoroscopically guided percutaneous antegrade urethral catheterization (PAUC). Design-Retrospective case series. Animals-9 client-owned neutered male cats with urethral obstruction and inability to pass a retrograde urinary catheter. Procedures-Information regarding the procedure and hospitalization was obtained from medical records. Long-term follow-up was obtained via medical record review or telephone interview. Results-Diagnoses included iatrogenic urethral tear (n = 6), obstructive urethral calculi (1), urethral ulceration (1), and urethral stricture (1). Seven of the 9 procedures were successful. The 2 patients in which PAUC failed had mechanical obstructions preventing guide wire access across the urethral obstruction. Procedure times ranged from 25 to 120 minutes. No complications were noted in any patients during the procedure. One patient was euthanized because of unrelated disease. Follow-up information was available for 6 of 8 surviving patients. No complications that could be directly attributed to the procedure were noted. All 6 patients had a perineal urethrostomy performed 0 days to 6 weeks following the procedure because of reobstruction of the lower urinary tract. None of these patients had documented urethral strictures and none had recurrence of clinical signs following perineal urethrostomy. Conclusions and Clinical Relevance-Results suggested that PAUC can be a simple, rapid, minimally invasive, and safe technique to facilitate transurethral catheterization in select cases. Patients with iatrogenic urethral tears may be good candidates. Patients with impacted urethral calculi, severe strictures or ulcerations, or a nondistended urinary bladder may be less amenable to PAUC.     

Managing traumatic urethral injuries

Urethral injuries are relatively common in male dogs and cats. Urethral epithelium has impressive regenerative properties, and healing by second intention is effective as long as there is mucosal continuity across the traumatized area. Principles of managing traumatic urethral injuries include an accurate patient assessment, including a determination of the extent of the urethral injury; correction of electrolyte or acid-base disturbances; provision of urinary diversion, particularly with pelvic or perineal urethral defects; drainage of extravasated urine; and selection of a surgical procedure to repair or bypass the injured portion of urethra. Treatment options include temporary urinary diversion through cystostomy or urethral catheterization and second intention healing, permanent bypassing of the traumatized area through urethrostomy proximal to the injury site, and primary repair of transection injuries. The scrotal site is the most frequently used and preferred site for urethrostomy in the male dog to bypass the injured penile urethra. Urethral surgery necessitates care and attentiveness to detail, considering that accurate approximation of urethral mucosa minimizes fibrosis and helps maintain an adequate luminal diameter. Avoidance of stricture and preservation of function are goals of managing traumatic urethral injuries.     

Perineal urethrostomy.

Perineal urethrostomy can be used successfully in male cats to help manage certain lower urinary tract diseases. Indications and surgical technique are discussed and illustrated. Potential complications encountered with the surgical technique along with methods for preventing and managing are elaborated. With experience, perineal urethrostomy can be performed successfully and with minimal complications.     

Presumptive pseudohypoaldosteronism secondary to chronic urinary tract obstruction from sloughed urinary bladder mucosa and urinary tract infection in a cat

Objective – To describe a case of presumptive secondary pseudohypoaldosteronism (PHA) in a cat with urinary tract infection and chronic urethral obstruction. The obstruction was believed to have resulted from sloughed urinary bladder mucosa secondary to pressure necrosis. Case Summary – A 5‐year‐old, 4 kg, castrated male Siamese cat presented for vomiting and stranguria. Medical history included a perineal urethrostomy for urethral obstruction. Physical examination revealed a large, painful, nonexpressible urinary bladder. Point‐of‐care testing demonstrated electrolyte derangements consistent with a postrenal azotemia and metabolic acidosis. Results of urine culture was positive for bacterial growth. Diagnostic imaging revealed presence of retroperitoneal fluid, marked urinary bladder wall thickening, bilateral hydroureter, mild bilateral pyelectasia, and small nephroliths. The patient was treated for a urinary tract obstruction and infection. In the 3 weeks following initial discharge, the patient was evaluated on multiple occasions for lethargy, intermittent vomiting, inappropriate urination, and progressive polyuria and polydipsia. Although the urinary bladder was easily expressed during repeat examinations, it was persistently distended and subjectively thickened upon palpation. Repeat ultrasound of the urinary tract showed evidence of sloughed tissue in the bladder lumen, likely secondary to chronic urethral obstruction and pressure necrosis. A cystotomy was performed to remove the necrotic tissue, and a revised perineal urethrostomy was done due to a partial urethral stricture. Bladder biopsies were obtained at this time. Postoperatively, the cat was reported by the owners to be urinating normally but continued to be polyuric and polydipsic in the week following discharge. One week after surgery, the cat presented in hypovolemic shock with laboratory findings consistent with a presumptive diagnosis of secondary PHA. New or Unique Information Provided – PHA has not been reported previously in a cat. This case report suggests that aldosterone resistance should be considered in cats with consistent laboratory findings and a history of documented obstructive uropathy and urinary tract infection.     

Hypospadias in a polar bear (Ursus maritimus).

Corrective surgery on a 1.5-yr-old male polar bear (Ursus maritimus) with hypospadias included amputation of the vestigial penis, bilateral orchiectomy with scrotal ablation, and distal perineal urethrostomy. Hypospadias in other species is a congenital deformity that may be caused by extra- and intrauterine factors resulting in a disruption of the testosterone balance during urethral development, but the causative mechanism in this bear is unknown. The urethrostomy site was functional without complications 8 mo after surgery.     

Two chondrosarcomas in the urethra of a German shepherd dog

An eight-year-old, male castrated German shepherd dog was presented with signs consistent with urinary obstruction. Cystoscopy and contrast radiography showed two distinct urethral masses. Penile amputation and perineal urethrostomy were performed to alleviate the clinical signs. Histopathology of the masses revealed two low-grade chondrosarcomas. At the time of writing, 18 months after surgery, the dog remained disease free.