Chapter 80 Surgery of the Urinary Bladder
Cystotomy is the most common surgical procedure of the urinary bladder in small animals and is commonly performed for removal of urinary calculi. Subtotal or total cystectomy may be indicated for management of benign or malignant urinary bladder neoplasia. The incised bladder wall heals quickly and regains nearly 100% of original tissue strength after healing. The mucosal lining of the bladder is quite delicate and easily becomes edematous, necessitating meticulous tissue handling and proper suture placement.
ANATOMY
• The urinary bladder is divided into three regions: (1) the cranial portion is the apex, (2) the caudal portion that joins the urethra is the neck, and (3) the segment between the apex and neck is the body.
• The ureteral openings and the urethral orifice form a triangular area on the dorsal aspect of the bladder called the trigone.
• The three ligaments of the bladder are composed of double layers of peritoneum. The ventral ligament extends from the ventral surface of the bladder along the ventral midline of the abdominal wall to the umbilicus. The ventral peritoneal ligament contains the urachus in the fetus. The urachus is an embryologic structure that connects the urinary bladder and the allantoic sac. The urachus closes and atrophies soon after birth, leaving a small scar at the apex of the urinary bladder. The lateral ligaments connect the lateral aspects of the bladder to the pelvic canal and enclose the ureters, deferent ducts, and umbilical arteries.
• The major blood supply to the bladder comes from the caudal vesical artery, a branch of the internal pudendal artery that lies in the pelvic fascia. The cranial vesical artery, present in only 50% of adult dogs, supplies the cranial aspect of the bladder. Venous blood drains into the internal pudendal veins. Bladder lymphatics drain into the hypogastric, sublumbar, and median iliac lymph nodes.
ANOMALIES OF THE URACHUS
Preoperative Considerations
• Persistent urachus results when the entire urachal canal remains patent after birth. Urine is voided through the urachal opening at the umbilicus. Treatment consists of surgical excision of the entire urachal tube.
• Vesicourachal diverticulum results when the origin of the urachus at the bladder apex fails to close. The diverticulum forms a pocket of urine, predisposing the animal to recurrent bacterial urinary tract infections (UTIs).
• Vesicourachal diverticula may be diagnosed by contrast radiography or uroendoscopy. Diverticulectomy is indicated in animals with persistent UTI. Urachal scars commonly are observed at the dome of the bladder and seldom cause a problem. In contrast to a urachal scar, a diverticulum is a discrete pouch or sac that opens into the bladder lumen.
Surgical Procedure—Persistent Urachus
Technique
3. Perform a routine ventral midline celiotomy from approximately 3-cm cranial to 3-cm caudal to the umbilicus.
4. Make an elliptical incision around the umbilical opening. Dissect the urachus from the surrounding tissues.
7. Create a full-thickness elliptical incision in the apex of the bladder around the origin of the patent urachus.
9. Submit samples of the excised vesicourachal junction for bacterial culture and susceptibility testing.
10. Remove the stay sutures and laparotomy sponges. Close the bladder as described under “Cystotomy,” “Technique.”
Postoperative Care and Complications
• Administer antibiotics based on the results of bacterial culture and susceptibility testing. Prolonged (>4 weeks) antibiotic therapy may be necessary to reduce the risk of recurrent UTI.
Surgical Procedure—Vesicourachal Diverticulum Excision
Technique
1. Patient positioning and surgical approach are the same as those described under Persistent Urachus.
2. Do not make an elliptical incision around the umbilicus; instead, use the approach recommended for cystotomy.
5. Make a full-thickness elliptical incision in the bladder wall around and approximately 5 mm from the edge of the diverticulum.
Postoperative Care and Complications
• Postoperative complications are rare. Recurrent infections after removal of the diverticulum are uncommon.
• Administer antibiotics based on the results of bacterial culture and susceptibility testing. Prolonged antibiotic therapy (>4 weeks) may be necessary. Reevaluate bacterial culture of the urine 1 week following the completion of antibiotic therapy.
CYSTOTOMY
Preoperative Considerations
• Neoplasia of the urinary bladder, polypoid cystitis, surgery involving the ureteral orifice(s) including neoureterostomy, and ureteral transposition require cystotomy.
Surgical Procedure
Technique
2. Prepare the ventral abdominal region and vulvar or preputial area for aseptic surgery. Irrigate the prepuce with antiseptic solution and include it in the aseptic field to enable intraoperative urethral catheterization, if necessary.
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