Introduction

Ovariohysterectomy is one of the most frequently performed surgical procedures in veterinary medicine.¹ The most common complications reported include hemorrhage, ovarian remnant syndrome, uterine stump pyometra, granuloma formation, urinary incontinence, and ureteral injury.² Although infrequently encountered, complications involving the urinary system have been reported to be caused by granuloma, bladder torsion, or ligation of the ureters with the ovarian or uterine stump ligatures.³

We reported our experience of successful surgical management of a 6 yr old female spayed Boston terrier who had a total cystectomy because of surgical error during an ovariohysterectomy. Total cystectomy has not been a previously reported complication associated with ovariohysterectomy.

Case Report

A 6 yr old spayed female Boston terrier was admitted for evaluation of acute onset of vomiting and anuria 4 days following a caesarian section and ovariohysterectomy for treatment of dystocia by the primary care veterinarian. Upon physical examination, the dog was quiet and alert. Mucous membranes were pale pink and tacky. A firm 3 cm mass was palpated in the caudal abdomen with no associated pain. The abdominal incision was intact and free of discharge. No other abnormalities were noted on physical examination. A complete blood count and biochemistry revealed anemia hematocrit at 21% (reference range 37–61%), an elevated blood urea nitrogen (BUN) at 103 mg/dL (reference range 7–27 mg/dL), elevated creatinine at 7.4 mg/dL (reference range 0.5–1.8 mg/dL), hyponatremia Na at 135 mmol/L (reference range 144–160 mmol/L), hyperkalemia K at 5.6 mmol/L (reference range 4.0–5.4 mmol/L), hyperphosphatemia at >16.1 mg/dL (2.5–6.1 mg/dL), and hypochloremia Cl at 103 mmol/L (reference range 109–122 mmol/L). No identifiable urinary bladder was found on an abdominal ultrasound. Both ureters were moderately dilated from their origin at the renal pelvis to the level where they terminated at an amorphous caudal abdominal mass measuring 1.61 cm in diameter. The left ureter measured 4.0 mm in diameter and the right ureter 2.9 mm in diameter. There was no evidence of ureteral peristalsis or intraluminal obstruction. The kidneys were normal in size with moderate bilateral hydronephrosis of 3.3 mm in diameter. At the terminus within the caudal abdominal mass, there were small hyperechoic shadowing structures associated with both ureters suspected to be suture material. The mesentery in the caudal abdomen was hyperechoic with a small volume of peritoneal fluid consistent with peritonitis. Based on these findings, a surgical error was suspected, and intermittent peritoneal dialysis was performed overnight in preparation for surgery the following day. Dialysis was initiated by the placement of a thoracic drainage catheter through the abdominal incision under a short anesthetic protocol and strict aseptic technique. An in-house dialysate solution was made using 30 mL 50% dextrose added to 1 L sodium lactate solution^a to make a 1.5% solution. To decrease clot formation and improve dialysate outflow, 200 U heparin was also added to the 1 L solution. A three-way stopcock was attached to the catheter to provide access for both the inflow and outflow dialysis bags, and intermittent dialysis was performed overnight every 3 hr at 10 mL/kg (1/3 of the ideal fluid exchange rate). The following morning, creatinine was rechecked and found to be 8.8 mg/dL (reference range 0.5–1.8 mg/dL), and potassium was within the normal reference range at 5.1 mmol/L (reference range 4.0–5.4). BUN and sodium were unchanged, and the packed cell volume was 19% (reference range 37–55%). Packed red blood cells were transfused (120 mL dog erythrocyte antigen 1.1 negative), and an exploratory celiotomy was performed. With the dog in dorsal recumbency, the previous abdominal incision was ∼8 cm in length and had to be extended for adequate exposure. The cranial abdomen and kidneys appeared grossly normal. Bilateral hydroureters were apparent. An amorphous mass with omental adhesions was present in the caudal abdomen. The ureters appeared to be entering this mass. The mass was carefully dissected free of adhesions and hematomas. Encircling sutures were present around the base of the mass. The sutures were cut and removed, and it was apparent that a large uterine stump and the neck of the bladder were present within the encircling sutures. A lateral suture was also present on each side of the mass and appeared to be encircling each ureter close to the bladder. These sutures were cut and removed. Approximately 95% of the urinary bladder had been previously excised. Once all the sutures were removed, the uterine stump and remaining portion of the bladder neck were separated. The uterine arteries were identified and ligated with a 3-0 Gylcomer 631^b. A circumferential ligature was placed more caudally on the uterine body, and the uterine stump was excised cranial to the ligature. The necrotic edges of the remaining neck of the bladder were debrided, resulting in a total cystectomy. Both ureteral papillae were within the necrotic portion of the bladder tissue. After resection of the narrowed and necrotic insertions of the ureters, they were incised and tagged with sutures and then spatulated at their distal viable aspect. The left ureter was reimplanted in the proximal urethra using a mucosal apposition technique with a 5-0 Gylcomer 631.⁴ A 12 cm segment of the jejunum was selected to be used for reconstruction of a bladder because of the short length of the ileum in this dog. The segment was isolated, preserving its blood supply. The remaining jejunum was anastomosed with a 4-0 Gylcomer 631 in a simple interrupted pattern (Figure 1). In the harvested segment of jejunum, a full-thickness incision was made on the antimesenteric border, and the mucosa was denuded using Metzenbaum scissors to the level of the submucosa (Figure 2A). The isolated and open segment of jejunum was doubled over on itself to form a “U,” and the opposing edges on one side were sutured together with a 4-0 Gylcomer 631 in an appositional pattern, so that the submucosa faced toward the lumen (Figure 2B). The urinary bladder was reconstructed by suturing the dorsal aspect of the opening of the new bladder to the proximal urethra (Figure 2C). Prior to completing closure, the right ureter was relocated into the jejunal patch using the mucosal apposition technique with a 5-0 Gylcomer 631 in a simple interrupted pattern. A 5-French red sterile urethral catheter^c was easily passed through both ureteral orifices. A 3.5-French sterile urethral catheter was cut to ∼4 cm in length and used as a right ureteral stent. It was sutured in place at the ureteral orifice with a 5-0 chromicgut^d and extended proximally into the ureter. The left ureter was not stented because of its location in the proximal urethra. An 8-French sterile urethral catheter was passed normograde out the vulva, sutured to an 8-French Foley catheter^e, and pulled back into the bladder. The remaining ventral aspect of the new bladder margin was sutured to the proximal urethra. Using the indwelling urinary catheter, saline was instilled into the new bladder, and no leakage was noted. A 7 mm Jackson‐Pratt closed suction drainage (JP drain) system (closed wound vacuum drain [silicone])^f was placed in the caudal abdomen, exiting lateral to the midline incision. The abdomen was lavaged with 2 L warm physiologic saline. A routine three-layer abdominal closure was performed. Recovery was uneventful. The urethral catheter was connected to a closed urine collection system postoperatively and remained in place for 6 days. Postobstructive diuresis occurred postoperatively, and IV fluids were adjusted accordingly. An abdominal ultrasound performed 9 days postoperatively showed increased dilation of the left renal pelvis (7.5 mm) and migration of the right ureteral stent proximally into the renal pelvis. The JP drain production decreased from 8 mL/kg/day to 2 mL/kg/day and was, therefore, removed. The dog was discharged from the hospital 9 days postoperatively. Prior to discharge, bloodwork showed the BUN and creatinine to be within their reference ranges at 12 mg/dL (reference range 9–31 mg/dL) and 1.2 mg/dL (reference range 0.5–1.5 mg/dL), respectively. Electrolytes were also within the normal reference ranges. On follow-up phone calls, the owner reported that the dog was posturing to urinate frequently as well as having intermittent urinary incontinence when sleeping. Two weeks postoperatively, an abdominal ultrasound revealed a persistent, although improving, left hydronephrosis and left hydroureter. The left ureter appeared to have a patent orifice into the proximal urethra (2.3 mm wide). The right hydronephrosis had resolved, and the right ureteral stent had migrated into a renal recess. Seven weeks postoperatively, an abdominal ultrasound showed essentially no change in position of the stent in the right kidney, so it was decided to remove the right ureteral stent at that time to avoid having a persistent source of inflammation or infection.

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A ventral midline celiotomy was performed, and the neobladder was well vascularized with a normal “bladder” appearance (Figure 3). Peristalsis was present in the neobladder. Both ureters appeared dilated, and the right ureter was tortuous. The right ureteral stent was palpable within the proximal ureter. A stab incision was made over the distal end of the stent in the proximal ureter, and the stent was removed. The ureterotomy was closed with a 5-0 Gylcomer 631^a in a simple continuous pattern. A JP drain was placed at the site of the ureteral incision, and a three-layer abdominal closure was performed. Recovery was uneventful, and the dog was discharged 3 days postoperatively. Urine that was collected at the time of surgery cultured positive for Corynebacterium sp. and Pasteurella sp. sensitive to and treated with clavulanic acid/amoxicillin.

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Five and a half months after the first surgery, the dog was presented for vomiting once each morning for 2 wk. A biochemistry test revealed electrolytes to be within normal limits: Na 153 (reference range: 144–160 mmol/L), K 4.4 (reference range: 3.5–5.8 mmol/L), Cl 118 (reference range: 109–122 mmol/L), mildly elevated BUN at 30 (7–27 mg/dL), and normal creatinine at 1.1 (0.5–1.8 mg/dL). An abdominal ultrasound revealed a large amount of floating echogenic debris and sediment within the new bladder lumen consistent with cellular or proteinaceous material. There was also a large amount of mineralized debris. The urine was straw colored and opaque with too numerous to count white blood cells, 3+ bacteria, 1+ mucus, and 2+ struvite crystals. Bacteria isolated from the urine included Enterococcus sp., Pasteurella multocida, and Streptococcus sp., sensitive to and treated with clavulanic acid/amoxicillin. One year after the first surgery, the dog was presented for recheck biochemistry, urine analysis, abdominal ultrasound, and urine culture. The dog was reported by the owner to be intermittently urinary incontinent but doing clinically well otherwise. The biochemistry was unremarkable, and the urine analysis revealed a marked number of bacteria. An abdominal ultrasound showed the reconstructed bladder had less sediment and debris compared with previously, static right hydronephrosis (1.55 cm), unchanged dilation of the right ureter (1.3 cm), and static left hydronephrosis (7.3 mm) with no ureteral dilation. Two years following the initial surgery, the owner reported that the dog was doing well with mild urinary incontinence and periodic urinary tract infections. Additional diagnostics such as IV pyelography and contrast cystography were offered to the owner but were declined. Cystoscopy would have also been a useful diagnostic tool that would have allowed for the evaluation of the lumen of the new bladder but was not available at our practice.

Discussion

Total or subtotal cystectomy has not been reported as a complication following ovariohysterectomy occurring at the time of surgery. In a case report describing an ileocystoplasty for urinary bladder reconstruction in a dog, a subtotal cystectomy was performed secondary to necrosis of the bladder wall occurring after an ovariohysterectomy with no evidence of encircling sutures around the urinary bladder or its vasculature.⁵ It was suspected that injury to the paired cranial and caudal vesical arteries had occurred, although there was no historical support for that hypothesis. In another case report, a colonic seromuscular augmentation cystoplasty was performed after an ovariohysterectomy that resulted in bladder torsion and subsequent necrosis of 90% of the bladder.⁶ Postoperative complications included ureteral stricture, pyelonephritis, and urinary incontinence but resulted in an overall good long-term outcome. Total cystectomy has been reported as a treatment option for the management of transitional cell carcinoma of the bladder in dogs; however, bladder reconstruction was not performed.⁷ Instead, the right and left ureters were sutured together to create a single lumen which was anastomosed to the vagina. Experimentally, dogs have been used as a model for bladder reconstruction to treat developmental abnormalities involving the genitourinary system in children and for adults with neurogenic or myogenic bladders.^8–10 Current techniques for augmentation cystoplasty include the use of the stomach, small intestine, large intestine, and cecum, with each segment having its own characteristic and specific complications.¹¹ In dogs undergoing bladder augmentation with an isolated flap of stomach, continued acid secretion resulted in histologic erosions and ulcerations in the bladder mucosa.^12,13 In humans, jejunal conduits have been shown to carry an increased risk of electrolyte imbalances; however, the use of short jejunal loops and oral electrolyte replacement therapy can minimize the occurrence of these complications.^14,15 The dog in this report had a very short ileum, and, therefore, it was decided to use a segment of jejunum both for the length and the ability to mobilize it to the caudal abdomen. The dog in this report did not have any electrolyte abnormalities on follow-up serum biochemistry analysis and did not require any supplementation. The ileum is the most frequently used intestinal segment for enterocystoplasty, both clinically in humans and experimentally in dogs. Ileal segments have been associated with the development of hyperchloremia, hypokalemic metabolic acidosis, and vitamin B₁₂ deficiency in people.^16,17 Routine ileocystoplasty had minimal effect on hematologic and biochemical parameters in dogs in one study.¹⁸ Other complications reported include bladder perforation, mucus production, stone formation, and bacterial infection.^19,20 Rupture of the augmented bladder is uncommon; in one study, it occurred at a rate of 8.6% in 500 augmentations in children.¹⁹ Bladder perforations have not been reported to occur in dogs with these procedures. The incidence of bladder stones in augmented bladders has been attributed to the production of mucus facilitating bacterial growth.²⁰ Denuding the mucosa has proven to decrease postoperative complication rates and promote urothelial expansion over the intestinal segment because of the mucus secreting nature of the digestive epithelium.^21,22

It has been shown that 25 min of an enzymatic treatment consisting of collagenase and trypsin is sufficient to remove the absorptive function of the intestinal segment of the augmented bladder.²³ In one study performed on dogs, removal of the submucosa and mucosa increased the amount of transitional epithelium resurfacing the augmented bladder compared with removing the mucosa alone. The dog in this report developed evidence of mineralized debris, mucus production, and bacterial infections, despite denuding the mucosal surface of the jejunal segment. The emergent nature of the presentation of the dog in this report did not permit acquisition of this enzymatic treatment; however, enzymatic treatment of the mucosal surface may have been advantageous in preventing mucus production and recurrent bacterial infections.

Urinary incontinence is a known sequel to resection of the trigone of the bladder. In a study evaluating a surgical technique for resection of invasive tumors involving the trigone, continence was maintained through preservation of the dorsal neurovascular pedicle to the proximal urethra.²⁴ The dog in this report had intermittent episodes of incontinence but retained the ability to posture and urinate. We suspect that there was inadvertent preservation of the neurovascular pedicles to the proximal urethra. In a study evaluating the function of the pelvic floor and the isolated urethra after removal of the bladder in dogs, the contractile potency of the urethral smooth muscles remained intact after preservation of the pelvic and pudendal nerves, particularly the branches supplying the proximal urethral.²⁵ In the future, special attention should be made to preserve the nerves supplying the proximal urethra to preserve continence after total cystectomy in dogs. Additional causes of incontinence in this patient likely include the location of the left ureter in the proximal urethra as well as urine retention and incomplete bladder expression.

Conclusion

This report suggests that jejunocystoplasty with bilateral ureteral reimplantation should be considered as a treatment option for dogs following iatrogenic total cystectomy. Peritoneal dialysis was elected over emergency surgery in this case to adequately stabilize the patient prior to such an extensive procedure. Creatinine was elevated postdialysis, most likely because of the low volumes infused or low osmolality of the solution. Small infusion volumes were used within the first 24 hr of dialysis to decrease the risk of dialysate leakage and minimize cardiovascular complications. Alternatively, increasing the glucose concentration would have enhanced the osmotic gradient, favoring the movement of fluid from the blood to the peritoneal cavity. The mucosa should be denuded at the time of surgery, and, if available, the use of an enzymatic treatment should be used to prevent regrowth of digestive epithelium. Preservation of the nerves supplying the proximal urethra will aid in maintaining contractile potency after total cystectomy in the dog.