Urinary Bladder

Introduction

Cystotomy is indicated to remove cystic and urethral calculi, to approach ectopic ureters, to examine the interior surface of the bladder for tumors, polyps, and ulcers, to remove blood clots, sloughed urothelium, or foreign bodies, and to repair some types of bladder rupture. Partial cystectomy is indicated to excise bladder neoplasms, polyps, ulcers, patent urachus, urachal diverticula, and infected urachal remnants. Total cystectomy has been used as a treatment for malignant tumors that are extensive or that involve the trigone and ureters. Various surgical techniques for urine diversion after partial cystectomy with or without the creation of a urine reservoir have been described, but all are associated with significant postoperative morbidity. Alternatives to total cystectomy include palliative treatment by placement of a permanent cystostomy catheter, chemotherapy,and radiation therapy.

Depending on the indication, preoperative assessment before cystotomy or cystectomy should include evaluation of renal function, urinalysis, and quantitative bacteriologic culture and diagnostic imaging of the bladder using survey radiography, contrast cystography, or ultrasonography.

Surgical Technique

Cystotomy

A caudal midline incision is made in female dogs and cats. In the male dog, a paraprepucial incision is used; the skin incision curves lateral to the prepuce, the prepuce is retracted laterally, and a midline abdominal incision is made through the linea alba.

A ventral cystotomy incision is recommended because it provides better access to the trigone, ureteral openings, and proximal urethra than a dorsal incision, and the risk of adhesions or leakage is similar with either location of the incision.¹ The bladder is isolated from the abdomen with moistened laparotomy sponges or towels. A retention suture is placed at the cranial end of the bladder, and a second suture is placed at the caudal end of the planned incision. The length of the incision is determined by the size of the calculi or by the extent of the planned exploration of the bladder interior. The bladder is emptied by cystocentesis using a 22-gauge needle and syringe (Figure 30-1). A stab incision is made into the bladder with a scalpel. The incision is extended cranially and caudally with scissors (Figure 30-2). Retention sutures can be placed lateral to the incision to help open the bladder and to allow inspection of the interior (Figure 30-3).
 

Calculi are removed with a bladder spoon or forceps. Passing a urethral catheter and flushing the urethra from the bladder and from the urethral opening alternately can often dislodge urethral calculi. The bladder lining is inspected, and abnormal appearing areas are sampled for biopsy. The ureteral openings can be identified in the trigone and catheterized if necessary. The bladder is flushed with warm saline before closure.

The bladder is closed in one layer with absorbable suture material. An inverting pattern (e.g., Cushing) or simple continuous is used in a bladder of normal thickness, and a simple interrupted pattern is used in a thickened bladder wall (Figure 30-4). The suture material should not enter the lumen of the bladder, but should incorporate the submucosal layer. The bladder closure can be tested by injecting saline to distend the bladder and evaluating the incision for leakage. The abdomen is lavaged with warm saline and is closed routinely.
 

Partial Cystectomy

Up to 75% of the urinary bladder can be excised and the remaining tissue closed around a 5 mL Foley catheter bulb. A return to normal bladder volume and function within 3 months is anticipated.

If bladder neoplasia is suspected, the bladder wall is gently palpated and a cystotomy incision is made at least 2 cm away from the bladder mass. The mucosal surface of the bladder is inspected for additional tumors. The mass should not be manipulated during the cystectomy. The bladder wall with the mass is excised with a 1 to 2 cm margin of grossly normal tissue. Care is taken to preserve as much of the blood supply to the bladder as possible. It is preferable to preserve the trigone with the ureters intact, but if necessary, the ureters can be reimplanted into another location in the residual bladder. After tumor excision, gloves and drapes should be changed and new instruments used to close the bladder and abdomen, to prevent tumor seeding.² Closure of the bladder incision is similar to the cystotomy closure described previously. Placement of simple interrupted sutures may facilitate apposition of the bladder remnant.

Postoperative Management

The patient should be allowed to urinate frequently. If this is not possible, the bladder should be kept empty for 2 to 3 days by intermittent catheterization or with an indwelling urethral catheter connected to a closed urine collection system. Following cystotomy, retrieved calculi are submitted for quantitative mineral analysis, and appropriate medical management is initiated to help prevent urolith recurrence. Following partial cystectomy, an indwelling urinary catheter should be placed if more than 50% of the urinary bladder is excised. Excised tissue should be submitted for pathologic examination. With suspected bladder neoplasms, evaluation of the tissue margin is facilitated by pinning the specimen flat to a corkboard and marking the edges of the excised tissue with India ink before fixing in formalin.

References

1. Desch JP II, Wagner SD. Urinary bladder incisions in dogs: comparison of ventral and dorsal. Vet Surg 1986:15:153-158.
2. Blake EH III, Ellison, GW, Roberts JF, et al. Biomechanical and histologic comparison of single-layer continuous Cushing and simple continuous appositional cystotomy closure by use of poliglecaprone 25 in rats with experimentally induced inflammation of the urinary bladder. Am J Vet Res 2006; 67:686-692.
3. Gilson SD, Stone EA. Surgically induced tumor seeding in eight dogs and two cats. J Am Vet Med Assoc 1990:11:1811-1815.
    

Introduction

Cystostomy tube placement is a method of diverting urine from its normal bladder and urethral flow. Clinical indications for cystostomy tube placement include temporary and permanent urine bypass of the urethra. Temporary bypass is indicated in patients with urethral obstruction due to urethral calculi, inflammation, or neoplasia. Temporary bypass may also be indicated in patients with bladder atonia while awaiting response to medication and for temporary urinary diversion after urethral surgery. Permanent cystostomy tubes can be used as palliative treatment for bladder neck or urethral neoplasia.

Latex or mushroom tipped or Foley urinary catheters have been used most commonly as cystostomy tubes. Low profile cystostomy tubes are more expensive but are less cumbersome and less prone to accidental removal. They are also more suitable for long term use.

Preoperative Management

In a patient with suspected urethral obstruction, placement of a transurethral catheter should be attempted. If a transurethral catheter cannot be passed, urethral obstruction can be temporarily bypassed by placement of a cystostomy tube. The tube can be placed quickly and with minimal anesthetic compromise to the patient. This placement allows for drainage of urine while awaiting more definitive diagnostic procedures or for stabilization of a critically ill animal before instituting more definitive therapy.

If urethral or prostatic neoplasia is causing significant urethral obstruction, a cystostomy tube can be placed through a minilaparotomy or during a staging laparotomy. The cystostomy tube can be used as permanent palliative therapy, or it can be placed while awaiting response to more definitive therapy, such as chemotherapy or radiation.

Surgical Technique

A minilaparotomy (1 to 2 cm skin incision) is made in the caudal third of the abdomen. Usually, the bladder is easily palpable, and the incision is made over the bladder (Figure 30-5A). The incision can be made on the midline through the linea alba, or paramedian through the abdominal body wall. In male dogs, it is often easier to make a paramedian incision lateral to the prepuce, or alternatively, the prepuce can be retracted laterally to make a midline incision. The bladder is exteriorized, and two retention sutures are placed to allow for retraction (Figure 30-5B).

A pursestring suture using synthetic absorbable suture is placed through the serosa and muscular layers of the bladder wall in the ventral portion of the exteriorized bladder. When a ventral midline approach is used, the tube is placed through a separate paramedian incision in the body wall; when a minilaparotomy is performed, the tube can be placed through the primary body wall incision. A stab incision is made into the bladder within the pursestring (Figure 30-5C), and the cystostomy tube is introduced into the bladder (Figure 30-5D). A Foley catheter (8 or 12-French) is recommended for temporary bypass, and the catheter balloon is inflated with sterile saline. If the catheter is to remain in place for weeks to months, a mushroom-tip (Pezzar) urinary catheter or a low-profile cystostomy tube is recommended. The omentum can be incorporated around the catheter (Figure 30-5E), or the retention sutures can be placed between the bladder and the body wall to help secure the “pexy” of the bladder. The incisions in the body wall and skin are closed around the catheter, and the catheter is secured to the skin (Figure 30-5F). The catheter is connected to a closed drainage system, or alternatively, the bladder can be intermittently drained. The catheter can be safely removed after 7 to 14 days, allowing for a strong adhesion to form between the bladder and body wall. After tube removal, urine leaks from the stoma for 1 to 3 days: the stoma is allowed to heal by second intention.
 

Postoperative Management

After urine flow is restored by temporary bypass of the obstructed urethra, fluid therapy is continued to correct dehydration, azotemia, and electrolyte and acid-base disturbances. Urine output is carefully monitored by continuous, closed-system drainage in the critically ill patient.

If the cystostomy tube was placed to remain for a longer period (i.e., urethral neoplasia, bladder atonia), the clients can be taught to drain the patient’s bladder intermittently with a syringe. The cystostomy tube should be protected from self-mutilation by the patient with an Elizabethan collar or side brace if necessary. Low-profile tubes offer an advantage over Pezzar or Foley catheters since they are less likely to become dislodged due to inadvertent snagging of the tube on various objects.

Over time, the presence of the cystostomy tube will cause a urinary tract infection. Prophylactic antibiotics are not recommended, because of the potential development of a resistant bacterial urinary tract infection or fungal infection. After removal of the tube, the urine should be cultured, and appropriate antibiotics should be administered. If the catheter is to remain in place permanently, the administration of antibiotics should be carefully considered only if the animal is showing systemic signs or discomfort from the urinary infection.

Suggested Readings

Smith JD, Stone EA, Gilson SD: Placement of a permanent cystostomy catheter to relieve urine outflow obstruction in dogs with transitional cell carcinoma. J Am Vet Med Assoc 206:496, 1995.

Stiffler KS, Stevenson MA, Cornell KK, et al. Clinical use of low-profile cystostomy tubes in four dogs and a cat. J Am Vet Med Assoc 223:325, 2003.

Stone EA, Barsanti JA. Surgical therapy for urethral obstruction in dogs. In: Stone EA, Barsanti JA, eds. Urologic surgery of the dog and cat. Philadelphia: Lea & Febriger, 1992.

Bray JP, Ronan SD, Burton CA. Minimally invasive inguinal approach for tube cystostomy. Vet Surg 38 (3): 411, 2009.
 

Introduction

Urethral sphincter mechanism incompetence is a common cause of urinary incontinence in the bitch. It can occur as a congenital or an acquired condition and has multifactorial origin. Among factors contributing to the pathophysiology of the condition is a caudally located bladder neck and proximal urethra (“pelvic bladder”), a common finding in bitches with urethral sphincter mechanism incompetence. The caudally located bladder neck may predispose to incontinence during increases in intra-abdominal pressure when this pressure acts on the intra-abdominal bladder but is transmitted less efficiently to the extra-abdominal intra-pelvic proximal urethra. A competent urethra maintains urinary continence under these conditions, but in a bitch with urethral sphincter mechanism incompetence, such disparity in pressure transmission can result in urinary incontinence. Thus, bitches, with this combination of disorders, leak urine at times of abdominal pressure increases, particularly when they are recumbent.

Indication

In a bitch with a “pelvic bladder”, colposuspension may alleviate urinary incontinence associated with urethral sphincter mechanism incompetence by moving the lower urogenital tract cranially, thereby positioning the bladder neck and urethra within the abdomen. After the procedure, increased intra-abdominal pressure is transmitted simultaneously to the bladder and to the bladder neck and proximal urethra. In this way, increases in intravesical pressure resulting from raised intra-abdominal pressure may be counteracted by simultaneous increases in urethral resistance.

Urethral sphincter mechanism incompetence is a multifactorial condition and colposuspension corrects only one of the factors. Thus, colposuspension is not expected to cure all animals. In a study of 150 bitches, approximately 50% were completely continent, with the degree and frequency of incontinence significantly reduced in a further 40%. The severity of the incontinence remained unaltered in 10% of bitches.¹ In another study, 55% of “spay-related” urinary incontinent bitches were completely dry, requiring no medical treatment, two months after surgery. However, less than 14% remained continent at 1 year with no treatment. With the addition of medication (usually phenylpropanolamine), 36% had complete control and another 41% were greatly improved 1 year after surgery.³

Our approach is to perform surgery in affected younger bitches (less than 8 years of age) as the first form of treatment in the hope that long term medical therapy and their potential side effects can be avoided. Colposuspension is delayed in juvenile bitches with congenital urethral sphincter mechanism incompetence until after the first estrus because more than half of such animals become continent after their first heat. Animals with severe congenital urethral hypoplasia may be unsuitable for colposuspension. In such animals, the bladder neck cannot be returned to abdominal position by colposuspension. Fortunately, such severe urethral hypoplasia is rare, and its treatment is described elsewhere.² In older bitches, colposuspension is reserved for animals that have failed to respond to medical therapy.
 

Surgical Technique

After general anesthesia is induced, the bitch is placed in dorsal recumbency with the hind limbs flexed. The ventral abdominal skin and vagina are prepared for aseptic surgery, the vagina by douching with dilute aqueous povidone iodine solution. An 8 French (smaller bitches less than 35 kg) or a 10 French (larger bitches more than 35 kg). Foley catheter is inserted through the urethra into the bladder, and the cuff is inflated. The catheter is then gently withdrawn until the cuff rests in the bladder neck. The presence of the catheter facilitates identification of the urethra and bladder neck during surgery.

A midline, caudal abdominal approach is made. The prepubic fat and fascia are separated by careful blunt and sharp dissection on both sides of the midline at the level of the pubic brim, and the prepubic tendons and external pudendal vessels are identified (Figure 30-6A). These vessels must be avoided during subsequent placement of sutures around the prepubic tendon.

The midline incision is continued through the linea alba of the abdominal muscle wall and extends caudally to the pubic brim. Self retaining (Gosset or Balfour) retractors are used to hold the rectus abdominis muscle edges apart, and the bladder is identified. Cranial traction on the bladder allows the intrapelvic bladder neck to be pulled into the abdomen and identified by the presence of the inflated Foley catheter cuff. Seeing the bladder neck and proximal urethra is often difficult because of the presence of local retroperitoneal fat.

The vagina is displaced cranially and is cleared of fat and fascia on both sides of the urethra. This is most easily accomplished by inserting a finger into the vagina (Figure 30-6B and C). The urethra is palpated through the ventral vaginal wall and is displaced to the bitch’s left. Using the finger in the vagina, the vaginal wall on the right side of the urethra is pushed cranially and ventrally toward the caudal end of the abdominal incision. The vaginal wall is exposed by using a dry swab to clean off the overlying fat and fascia in a caudolateral direction (Figure 30-6C). The bladder neck can be seen as a swelling because of the Foley catheter cuff in the bladder. The vaginal wall is grasped with Allis tissue forceps. The technique is repeated on the other side of the vagina (Figure 30-6D). The surgeon then changes gloves, and the vulva is covered with a large sterile swab or surgical drape throughout the remainder of the procedure.

When the surgeon’s finger and the patient’s vagina are of incompatible sizes (very large or very small bitches or those with gross vaginal strictures or septa), the vagina has to be located by blunt and sharp dissection of the overlying fat and fascia on either side of the urethra, grasped with tissue forceps, and then pulled cranially. This is more difficult than the use of a finger in the vagina, and, fortunately, most bitches with urethral sphincter mechanism incompetence are of a size compatible with one’s finger. It is sometimes helpful in extremely large or small bitches to identify the vagina by inserting a Poole suction tip or a closed Carmalt clamp.

The vagina must now be anchored cranially to maintain the bladder neck in an intra-abdominal position. The vagina is sutured to the prepubic tendon on each side of and approximately 1 to 1.5 cm away from the midline. The sutures (monofilament nylon) are passed through the abdominal wall caudal to the tendon, in and out of the vaginal wall (as far laterally as possible), and back out of the abdominal wall cranial to the tendon, avoiding any abnormal twisting of the vaginal wall (Figure 30-6E). The sutures may enter the vaginal lumen during this procedure, hence the need to prepare the vagina for aseptic surgery.

One or two sutures are placed around the prepubic tendon, depending on the size of the bitch and the position of the external pudendal vessels laterally. Most affected bitches are medium to large breeds, and the optimum number of sutures is two around each tendon (Figure 30-6F). Number 0 nylon is suitable for most bitches, but No. 1 nylon should be used in very large breeds. On the rare occasions when colposuspension is performed in small or toy breeds, it may only be possible to place one suture through each side of the vagina and around each prepubic tendon.

Before the sutures are tied, they are pulled tight to ensure that, after they are tied, the urethra will not be compressed against the pubis by an arch of vagina (See Figure 30-6F). Compression on the urethra may result in postoperative dysuria. The surgeon should be able to insert the tip of a blunt instrument such as Mayo scissors or Carmalt forceps easily between the urethra and the vaginal arch and pubis. If the urethra is compressed, the sutures should be repositioned. This is rarely a problem when the sutures have been placed as far laterally on the vagina as possible. After the sutures are properly placed, they are tied, the Foley catheter is removed, and the abdomen is closed routinely.

Postoperative Care

Preoperative, perioperative, and postoperative analgesics are used routinely. These are not usually required after the first 24 hours. Antibiotic therapy (e.g., amoxicillin) is used for 10 days postoperatively as a precaution to minimize the risk of peritonitis in case colposuspension sutures have entered the vaginal lumen. We have never encountered this complication. The use of a rectal thermometer to take the animal’s temperature postoperatively is avoided because some bitches are sensitive in this area for a few days after surgery. In some bitches, local subcutaneous tissue swelling occurs, presumably because of the small dead spaces left after dissection to expose the prepubic tendons. Such swelling is not a problem and resolves spontaneously within 5 to 7 days. The animal is closely observed for signs of dysuria and to determine whether the incontinence has resolved. In most successful cases, the response is immediate, although some bitches remain incontinent for weeks before becoming continent. Skin sutures are removed routinely 7 to 10 days after the surgical procedure.

Possible Complications

Because the surgical procedure involves trauma to intrapelvic structures, some animals are stimulated to strain, usually immediately after recovery from general anesthesia. This can be controlled by the administration of appropriate analgesics. Rarely, some bitches find the first postoperative defecation uncomfortable if the feces are firm and bulky. This problem can be controlled with stool softeners.

Dysuria may occur immediately postoperatively. This complication is rare (approximately 5% of dogs in our experience) and may be caused by vaginal stimulation by the surgical procedure leading to suppression of the micturition reflex or reflex dyssynergia. Clinical observations and the response to diazepam suggest that reflex voluntary dyssynergia is the most likely cause of dysuria after colposuspension. It may be exacerbated by recent estrogen therapy, and so any estrogen therapy should cease at least 1 month before the operation. Voluntary dyssynergia usually responds to diazepam at a dose of 0.2 mg/kg by mouth two or three times daily. An indwelling urinary catheter can be used for a few days if necessary in the few animals that are unable to urinate at all. A further potential cause of dysuria is compression of the urethra against the pubis by the vagina. Care should be taken during surgery to avoid placement of vaginal sutures too close to the urethra.

Bitches that are allowed to be active after colposuspension may tear the sutures from the vagina. This is more likely to happen if these animals are allowed to jump, and owners should be advised of the necessity to restrict the exercise of their animals to leash walks only for 1 month postoperatively.

“Hymen” formation with accumulation of vaginal secretions causing dysuria or dyschezia is a rare, longer-term complication of colposuspension. This complication is caused by breakdown of a pre-existing vestibulovaginal stricture during the operation and subsequent healing of apposing raw areas of vagina to form a barrier across the vaginal lumen. It can be treated by breaking down the “hymen”.

Acknowledgment

We wish to thank Brenda Bunch, MA, of the College of Veterinary Medicine, North Carolina State University, for drawing the illustrations.

References

1. Holt PE. Long-term evaluation of colposuspension in the treatment of urinary incontinence due to incompetence of the urethral sphincter mechanism in the bitch. Vet Rec 1990;127:537-542.
2. Holt PE. Surgical management of congenital urethral sphincter mechanism incompetence in eight female cats and a bitch, Vet Surg 1993;22:98-104.
3. Rawlings CA, Barsanti JA, Mahaffey MB, et al. Evaluation of colposuspension for treatment of incontinence in spayed female dogs. J Am Vet Med Assoc 2001;219:770-775.

Suggested Readings

Gregory SP. Review of developments in the understanding of the pathophysiology of urethral sphincter mechanism incompetence in the bitch. Br Vet J 1994;150:135-150.

Holt PE. Urinary incontinence in the bitch due to sphincter mechanism incompetence: surgical treatment. J Small Anim Pract 1985;26:237-246.