Surgery of the Feline Urinary Tract
Howard B. Seim III, DVM, Dipl. ACVS
Make a ventral incision in the bladder wall
Close the bladder with a single layer
50 - 60% of the bladder wall can be resected
Be sure and remove the ureter during nephrectomy
Cystotomy is indicated for removal of cystic calculi, mucosal biopsy and culture and sensitivity of chronic recurrent cystitis, biopsy of mural lesions.
The patient is positioned in dorsal recumbency and the abdomen prepared for a routine caudal midline incision. Male cats are positioned with their hind legs tied slightly forward. The prepuce and penis are included in the sterile preparation so the surgeon can provide normograde and retrograde urethral flushing in the sterile field. The prepuce and penis are prepared by flushing with 0.01% Betadine solution. The abdomen is entered via caudal ventral midline celiotomy. Once the bladder is located and exposed a stay suture of 3-0 suture material is placed at the bladder, the bladder is retracted cranially to expose the ventral surface, and a second stay suture placed in the bladder neck. The bladder is then isolated from surrounding viscera by packing it off with moistened laparotomy pads and drained via a needle and syringe. If suction is available, a stab incision is made in the proposed cystotomy incision line (i.e., a relatively avascular area on the ventral aspect of the bladder), the suction tip introduced into the lumen of the bladder, and the urine removed. Once the urine has been evacuated the stab incision is lengthened with Metzenbaum scissors; a 4 - 5 cm incision should be made to provide adequate visualization of the bladder lumen. A ventral cystotomy incision provides better access to the trigone, ureteral openings, and urethra. Dorsal cystotomy incision is not recommended. Additional exposure can be gained by placing a stay suture on each side of the incision. A finger is inserted into the bladder to check for calculi or other lesions, particularly at the neck region. Eversion of the bladder wall also allows visualization of the apex region to check for diverticula. A bladder wall biopsy is taken for culture and susceptibility testing and histopathologic evaluation. A 3.5 to 5 French catheter is used to flush the urethra in a normograde and retrograde direction to ensure all urethral and cystic calculi are removed.
Bladder wall closure
Recently it has been shown that a single layer appositional suture technique is equally as effective as the classic double inverting patterns commonly used. Advantages of a simple appositional closure include decrease surgery time, minimal amount of inverted tissue in the bladder lumen, water-tight seal, and more available bladder wall for closure in patients requiring partial cystectomy. The cystotomy may be closed with a single layer, simple interrupted or simple continuous suture pattern using absorbable suture material. 2-0 to 3-0 suture are used for dogs and cats, respectively. After closure is complete, stay sutures are removed and the bladder is returned into the abdomen. Abdominal wall closure is routine.
Partial cystectomy is indicated for the removal of bladder wall neoplasia and resection of persistent urachal diverticula.
Partial cystectomy should be performed when the portion of bladder wall requiring resection is not associated with the bladder neck and trigone. Pathology located in the apical or ventral fundic portion can be considered for partial bladder wall resection. Approximately 50 -60% of the bladder wall can be removed and still have a functional bladder capacity. When considering a partial cystectomy for a mass or ulcerative lesion, it is best to make the initial cystotomy incision part of the final cystectomy incision. To do this, first palpate the bladder lesion, determine the location on the bladder wall, and make your initial cystotomy incision 1 - 2 cm away from the margin of the lesion. The bladder is opened, the lesion exposed, and the second bladder wall incision completes the partial cystectomy. The bladder wall is closed with a simple continuous or simple interrupted appositional pattern using 3-0 synthetic absorbable suture material (i.e., Maxon, PDS, Dexon, Vicryl) with a swaged on fine taper-point needle. If greater than 50% of the bladder wall is resected the surgeon should consider an indwelling urinary catheter postoperatively; I generally use a 3.5 or 5 French feeding tube in male cats and a 6 - 8 French Foley catheter in females. Catheters can generally be removed in 5 - 7 days.
Ureterotomy is indicated for cats that have developed ureteral calculi or have passed a calculus from the renal pelvis into the ureter. Cats with calcium oxalate calculi have a increased incidence of ureteral calculi.
The cat is placed in dorsal recumbancy and a midline abdominal incision from xyphoid to pubis is made. The bladder, ureters and kidneys are examined for the presence of palpable calculi. A cystotomy is performed to evaluate the bladder wall and remove any cystic calculi. Examination of the ureteral openings is also performed. If a calculus is located at the ureteral opening into the urinary bladder, attempts to manually pass the stone into the bladder is done first. Care is taken not the traumatize the ureter. As most calcium oxalate stones are embedded in the wall of the ureter, this technique often fails. If a ureteral calculus is located anywhere between the renal pelvis and urinary bladder, the ureter should be catheterized from the kidney. The technique is as follows:
1) The kidney is dissected from its attachment to the retroperitoneal space.
2) The capsule is identified and the kidney rotated 180o to expose the dorsal surface.
3) The ureter is identified as it becomes the renal pelvis. The renal pelvis is exposed for easy visualization.
4) A 14 gauge needle is passed into the greater curvature of the kidney parenchyma and passed to the level of the renal pelvis (if slight hydronephrosis is present, urine will come out of the needle under slight pressure as the needle enters the pelvis).
5) A 3.5 French catheter is passed into the needle, into the renal pelvis, and directed into the ureter. The catheter is passed until it comes in contact with the ureteral stone.
6) Sterile PSS is injected into the catheter and the surgeon attempts to hydropulse the ureteral stones into the bladder. As most calcium oxalate stones are adhered to the ureteral wall, this may be unsuccessful.
If hydropulsion is unsuccessful, the surgeon should attempt ureterotomy and stone removal. As most calcium oxalate stones are adhered to the ureteral wall, multiple stones may require multiple ureterotomies. Closure of the ureterotomy is performed using 6-0 or 7-0 Dexon with a swaged on cutting needle in a simple interrupted pattern. Suturing the ureter may be difficult due to the irritated ureteral wall secondary to the embedded calculi.
If ureteral stones are close to the bladder, an alternate course of action could be to excise the ureter containing the stones and re-attaching the ureter to the dome of the bladder. This reattachment is performed as for ectopic ureter repair. A tunneled ureteroneocystostomy is performed with ureteral spatulation and suturing to bladder mucosa with 6-0 or 7-0 Dexon in a simple interrupted pattern.
Pyelotomy is indicated for removal of calculi located in a dilated renal pelvis.
The dorsal aspect of the kidney is exposed as described in ureteral surgery. The renal pelvis is exposed; all perirenal and peripelvic fat is dissected from the renal pelvis. A 0.5 - 1 cm incision is made in the renal pelvis with a #15 bard parker scalpel blade. The pelvis is palpated with a mosquito hemostat to encourage removal of the pelvic stone. Calcium oxalate stones are most commonly found in the renal pelvis of cats. These stones are commonly adhered to the pelvic wall and are difficult to remove. Pyelotomy should not be attempted unless the stone is located in a "dilated" renal pelvis.
Nephrectomy is indicated for renal neoplasia, hydronephrosis, severe pyelonephritis (renal abscess), nephroliths, polycystic kidney, non-functional kidney associated with ectopic ureter, traumatic rupture/avulsion.
Nephrectomy is rarely done for the removal of a normal kidney (except harvesting a kidney for renal transplantation); therefore, the surgeon must be aware that significant pathology may influence the difficulty of renal resection. In many instances the renal capsule is adhered to the retroperitoneal structures and the hilar region may be difficult to dissect and visualize. A midline celiotomy from xyphoid to pubis is recommended for proper exposure and visualization of the affected kidney. If the left kidney is involved, exposure is generally easier due to its caudal location (i.e., mid abdomen) in the abdominal cavity. If the right kidney is affected, exposure and visualization is more difficult due to its relative cranial location and association with the caudate process of the caudate lobe of the liver. Once the affected kidney has been identified surrounding viscera is isolated with laparotomy pads and retracted with malleable retractors. An attempt is made to enter the retroperitoneal space to release the kidney from its attachment there. Dissection may be difficult if adhesions are present. Once the kidney is released from the retroperitoneal space the dorsal and ventral aspect of the hilar region is dissected until visualization of the renal artery, renal vein, and ureter is adequate. The artery and vein are best visualized on the ventral aspect of the hilus and the ureter is best visualized dorsally. Each structure is isolated, the renal artery and vein are ligated separately and the ureter transected between clamps. The renal artery is double ligated with 2-0 or 0 suture material and divided. The vein is similarly ligated. A separate transfixing ligature of 3-0 suture material may be passed through the lumen of the artery, distal to the first ligature. The kidney is removed and the ureteral attachment to the bladder is located. The ureter is transected close to the bladder wall and ligated using 2-0 or 0 absorbable suture material. Traction is placed on the ureter from the clamp located on its proximal end. The ureter will "slip" out of the retroperitoneal space without further dissection. If a segment of the ureter remains, formation of a ureterocele may occur. A final inspection is then made of the ligatures and the abdomen is closed routinely.