Perineal Urethrostomy (PU) in Cats

Overview of the Perineal Urethrostomy (PU) Surgery in Cats

Perineal urethrostomy, commonly referred to as a “PU”, is the procedure that is done to make a new opening in the urethra in the perineal area (the area between the scrotum and the anus). The procedure is most commonly done in male cats that suffer from Feline Lower Urinary Tract Disease (FLUTD) and to bypass an obstruction of the urethra in the penis. It is also indicated if there is trauma to the penis or lower urethra.

Most FLUTD cats are 2-6 years old neutered males, sedentary and overweight. The cause of FLUTD is unknown, but FLUTD cats are predisposed to urethral obstruction. And an animal that has suffered trauma to the urethra, either from a laceration caused by a broken pelvic bone, direct injury to the penis, or from traumatic catheterization of the urethra, may require a perineal urethrostomy.

Questions Your Vet May Ask About Your Cat

Your veterinarian will ask you many questions to develop a complete history of the progression of the problem in the cat. These questions will include:

• How is your pet’s appetite?
• Is your pet active?
• What is your pet’s demeanor?
• Has he been urinating normally
• Has there been any straining to urinate?
• Has there been any blood in the urine?
• How long has the problem been going on?

Your veterinarian will also examine your cat completely, including checking for a fever and listening to his heart and lungs. He/she will palpate (feel) you pet’s abdomen to check for an enlarged bladder, fluid in the abdomen or pain in the abdomen. Animals that cannot urinate due to an obstructed urethra can become very ill and may require emergency treatment.

Diagnostic Tests Before Perineal Urethrostomy (PU) in Cats

• Blood and urine tests are submitted to look for electrolyte abnormalities, signs of kidney failure or urinary tract infection. These tests will also identify abnormalities in kidney or liver function, which is important to know if your pet needs general anesthesia and surgery.
• Radiographs (x-rays) may be taken of the abdomen to look for stones in the bladder or urethra which may be causing an obstruction.
• An abdominal ultrasound is also helpful in identifying stones or other abnormalities in the bladder or rest of the urinary tract.

Treatment of Cats with a Perineal Urethrostomy Surgery

• If the urethra is obstructed and your pet cannot urinate, he may become very ill and require emergency stabilization. This can include intravenous fluids and emergency urethral catheterization.
• Many cats must be tranquilized or anesthetized in order to place a urinary catheter. If the obstruction cannot be relieved and the cat cannot be catheterized, a peritoneal dialysis catheter can be placed into the abdomen or a tube cystostomy can be placed into the bladder to allow removal of the urine and/or stabilization of the electrolyte abnormalities.
• Once the patient is stable, the perineal urethrostomy can be performed. During a perineal urethrostomy, the penis is removed and the wider diameter pelvic urethra is opened and sutured to the surrounding skin, creating a new permanent opening in the urethra, just below the anus.

Home Care

• Closely follow your veterinarian’s instructions on post-operative care in order to get the best results.
• The patient should wear an Elizabethan collar to avoid licking the new urethral opening as it heals. Trauma to the new opening could cause it to scar and close over, necessitating further surgery.
• The stitches should be removed after the cat has been tranquilized, since removing stitches in such a sensitive area is mildly uncomfortable. In addition, if the cat should move suddenly during removal of the stitches, the new urethral opening could be damaged.

Information In-depth on Perineal Urethrostomy (PU) in Cats

Perineal Urethrostomy (PU) is the medical term for the creation of a new opening in the urethra (the tube which carries urine from the bladder to the outside). This is done in the perineum, which is the area between the scrotum and anus. A PU is done to bypass the smaller diameter urethra in the penis and open the larger diameter urethra in the pelvic area.

Indications for a PU include:

• Chronic urethral obstruction as a result of Feline Urologic Syndrome (FLUTD)
• Obstruction due to urinary tract stones
• Damage to the urethra from an injury or from a urinary catheter

The cause for FLUTD is unknown. Most cats with FLUTD are young adult neutered males, 2-6 years old. They are often sedentary and overweight. They develop grit and plugs of debris in their urine which can obstruct the flow of urine out the urethra.

If the animal has suffered trauma to the pelvis, especially if there are fractured pelvic bones, the urethra can become damaged as well. These cats may also require urethrostomies.

Cats that are obstructed due to FLUTD need to be unobstructed by means of a urinary catheter. This can be difficult and can result in damage to the urethra. If the urethra is damaged, or if a catheter is unable to be passed, a PU may be necessary.

Diagnosis In-depth Prior to Perineal Urethrostomy (PU) in Cats

• History. Your veterinarian will ask you many questions regarding the development and progression of the problem. If your pet is obstructed and unable to urinate, he may require emergency stabilization. This could include intravenous fluids, and emergency urethral catheterization or other method of relieving the pet of urine.
• Physical exam. Your veterinarian will perform a complete physical exam. This includes listening to the heart and lungs, taking the pet’s temperature, and palpating the abdomen. Your veterinarian will assess your cat’s bladder for size, pain and the ability to express urine.
• Radiographs (x-rays). Radiographs are often taken to look for stones in the bladder, urethra or other parts of the urinary tract. They are also necessary if the animal was involved in a traumatic event to look for injuries to the ribs, diaphragm and lungs.
• Ultrasound. An ultrasound (sonogram) of the abdomen is often helpful to identify stones in the urinary tract and to evaluate the other organs in the abdomen.
• Blood and urine tests. Blood and urine tests are submitted to look for anemia, evaluate kidney and liver function prior to anesthesia, and evaluate the oxygen and electrolyte levels in the blood. All of these tests are important in determining if the pet is stable for anesthesia. Animals that are unable to urinate can have severe abnormalities in their kidney values and electrolyte levels, requiring intravenous (IV) fluid therapy as well as monitoring the heart for abnormal rhythms.

Therapy In-depth with Perineal Urethrostomy (PU) in Cats

• Emergency stabilization: If your pet is unable to urinate, and has severe abnormalities in his blood work, emergency stabilization may be necessary. This involves IV fluids, heart monitoring and passing a urinary catheter to relieve the obstruction.
• If the obstruction cannot be relieved via urethral catheterization and the cat is not stable for a prolonged anesthesia and surgery, emergency methods of draining the bladder and/or eliminating the blood waste products are necessary. An emergency cystostomy can be done, which involves placing a tube directly into the bladder to drain the urine. Alternatively, a peritoneal dialysis catheter can be placed, which is a catheter placed in the abdominal cavity. Fluid is infused into the catheter to dilute and remove the blood waste products that have accumulated as a result of the urethral obstruction.
• Once the pet is stable and a perineal urethrostomy has been determined to be necessary, or if the obstruction cannot be relieved, your pet is placed under general anesthesia and surgery is done.

The surgery involves removing the penis and scrotum (and testicles if the cat has not already been castrated) and making a new opening in the wider area of the pelvic urethra. The urethral lining (mucosa) is sutured to the skin of the perineum. The skin will heal to the mucosa, creating a new permanent urethral opening.

• After surgery, an Elizabethan collar is placed on the cat to prevent him from licking the new urethral opening. The abrasive tongue can damage the healing tissues. Your pet will need to be monitored and treated for pain and any other abnormalities found in the blood work. This can involve IV fluids and may require a few days in the hospital.
• If stones were removed, they are submitted for analysis to see what type of minerals they are made of. A diet change may be necessary to prevent their recurrence.
• Antibiotics may be necessary, especially if there was a concurrent urinary tract infection.
• After about two weeks, your cat must have the stitches removed from the urethrostomy site. They may be removed after the cat has been sedated. Removing stitches in this sensitive area is mildly uncomfortable and if the cat moves suddenly during suture removal, the new urethral opening can be damaged.
• If the urethrostomy does not heal appropriately or becomes damaged, it can scar or completely close down. This is called a “stricture” and requires further surgery to re-open the urethra.

Follow-up Care for Cats After Perineal Urethrostomy

Optimal treatment for your pet requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your pet does not rapidly improve.

• Administer all prescribed medications as directed. Alert your veterinarian if you are experiencing problems treating your pet.
• Closely follow your veterinarian’s instructions for post-operative care, including exercise restriction for 1-2 weeks. This allows the incision to heal.
• Contact your veterinarian right away if your pet has difficulty urinating.