Feline urinary diversion procedures (Proceedings)
Urine diversion techniques are performed to temporarily or permanently divert urine from its normal anatomic course from the kidney through the ureter to the bladder and finally through the urethra. Veterinarians are most familiar with temporary urine diversion (urethral catheters) that are often used to stabilize animals that are sick as a result of metabolic changes associated with urinary tract obstruction. Temporary diversion (peritoneal drainage) may also be used as a bridge to more definitive surgical procedures such as repair of a ruptured urinary bladder.
Permanent urinary diversion is performed as a surgical procedure to redirect or reconstruct portions of the urinary tract that have been damaged by trauma or neoplastic involvement or for palliation of recurring urethral obstruction. Most permanent procedures performed in animals have been to circumvent areas of the urethra prone to obstruction with calculi or mucus plugs.
Attempts at PU in the feline were made initially in the 1950's by Carbone. Initial attempts failed because of the lack of recognition that the obstruction occurred in the penile urethra and initial urethrostomy techniques excised only the distal portion of the penile urethra. Over the next 15-20 years, surgery evolved/improved and the classic Wilson-Harrison urethrostomy was described in 1974. Other variations of the technique have been described but the basic principals remain unchanged. MANY PU's were performed in the 1970's and 1980's and continue to be performed today although total numbers have decreased due to dietary management used with Feline Urologic Syndrome (FUS). A report from the U. of Minnesota described the frequency of this disease (FUS) as declining from 40 cases/1000 cats evaluated in the 1980's to 20 cases/1000 cats evaluated in the 1990's. Similarly, the frequency of urethrostomy decreased from 19/1000 cats in the 1980's to 2 casaes/1000 cats in the 1990's. There is some evidence that the prevalence of calcium oxalate stones in cats have increased over the past 10 years probably due to popular acidifying diets.
A. Indications/Rule outs for PU