Step-by-Step Cystotomy

Updated July 2025 by Adrienne Balionis, DVM, and Jason Tarricone, DVM, DACVS (SA); VCA Palm Beach Veterinary Specialists, West Palm Beach, Florida.

Indications for cystotomy include exploration of the lower urinary tract, removal of cystic and urethral calculi (Figure 1), correction of ectopic ureters, removal of masses (eg, polyps), and biopsy.

FIGURE 1 Cystotomy for multiple cystoliths

Cystotomy can be completed via ventral midline celiotomy (most common), which can be extended caudally with a parapreputial incision, or a limited caudal midline approach in conjunction with cystoscopy or urethroscopy. Although the limited approach may be less invasive, total costs are often higher with a longer anesthetic period compared with the traditional open approach, and specialized equipment is required.^1,2

Preoperative Considerations

Patients obstructed prior to surgery should be stabilized, and azotemia should be treated. Untreated azotemia can increase sensitivity to anesthetic drugs.³ Hypotension should be avoided intraoperatively to limit risk for kidney injury. Preoperative radiography can help ensure no stones are obstructing the urethra. If the urethra is obstructed, a urinary catheter can be used to unblock the patient and be left in place for passive urination until surgery. All patients should receive perioperative antibiotics. In a study, antibiotics administered 30 minutes prior to surgery did not affect culture results compared with antibiotics administered after diagnostic samples were obtained intraoperatively.⁴

Positioning & Location

For cystotomy, the patient should be in dorsal recumbency. Male dogs can be positioned with the pelvic limbs extended caudally so the prepuce can be included in the prepared field for possible urethral catheterization. Cats and female dogs can be placed with the pelvic limbs in a frog-leg position with the tail hanging over the surgery table to provide good access for normograde or retrograde urethral catheterization intraoperatively; this positioning also works for male cats when cystotomy is combined with urethral catheterization or perineal urethrostomy.

The ventral abdomen should be clipped and aseptically prepared from the xiphoid to the caudal aspect of the pubis. The perineum can also be included. The prepuce or vulva should be flushed with antiseptic solution (eg, 0.05% chlorhexidine), surgically prepared, and included in the field to facilitate intraoperative catheterization. The urinary catheter should be antiseptically prepared if placed before surgery.

In cats and female dogs, a ventral midline celiotomy is performed from just caudal to the umbilicus to the cranial brim of the pelvis. In male dogs, a parapreputial skin incision is used. Ligation or electrocoagulation of the preputial branches of the caudal superficial epigastric vein and SC vessels minimizes bleeding. The preputial muscle should be transected and the prepuce retracted to the opposite side in preparation for midline celiotomy. The preputial muscle can be tagged with a suture for identification during closure.

Although cystotomy can be performed on the dorsal or ventral surface of the bladder,⁵ ventral midline cystotomy is recommended. Ventral cystotomy provides excellent visualization of the bladder lumen—especially the trigone area—and can be extended into the proximal urethra if additional exposure is necessary. Visualization of the trigone is important to avoid damage to the ureters during cystotomy and closure.³

Catheterization

The bladder can become thickened and edematous with prolonged exteriorization and repeated manipulations. Stay sutures can reduce repeated grasping of the bladder. Moist lap sponges or radiopaque gauze can be used to cushion the bladder during externalization.³

The urethra can be catheterized normograde (from bladder to urethral orifice), retrograde (from urethral orifice to bladder), or in both directions to verify patency and to flush calculi, when present, from the urethra. Placement of an indwelling urethral catheter in small female dogs and female cats can be facilitated by passing a catheter normograde from the bladder, attaching it to the tip of a second catheter, and withdrawing the normograde catheter to pull the indwelling catheter through the urethra and into the bladder if retrograde placement is difficult.

Prior to closure, the bladder should be flushed both normograde and retrograde to ensure no stones are present. The current author uses a nanoscope in a normograde fashion to evaluate the bladder and urethra for stones, but advanced imaging may not be practical in the general clinic.

Suture Selection & Closure

Simple interrupted, simple continuous, simple continuous oversewn with an inverting pattern (eg, Cushing), single layer Cushing pattern, and Cushing pattern oversewn with the Lembert pattern have been used.^3,5-9 Inverting patterns should be avoided when the bladder wall is thickened or friable.

A simple interrupted or simple continuous pattern can be used in normal or thickened bladders; however, a simple interrupted pattern is recommended over a simple continuous pattern. In the current author’s experience, almost all cases of postoperative uroabdomen are attributed to a failed closure of the bladder wall with a simple continuous pattern. The bites should engage the seromuscular layers and submucosa (holding layer), while avoiding penetration of the mucosa. Suture bites should be 3 to 4 mm apart with similar distance between sutures regardless of closing pattern. In a normal bladder, a simple continuous pattern can be oversewn with a Cushing pattern at the discretion of the surgeon, but there is no demonstrated benefit over a single layer closure.⁷ If an inverting pattern is used, excessive inversion of tissue, which could result in obstruction, should be avoided.

A monofilament intermediate-lasting absorbable suture material (eg, poliglecaprone 25, glycomer 631) in size 3/0 to 5/0 on a taper point needle works well. Resistance should be felt when the submucosa is engaged. Nonabsorbable sutures may predispose to calculi formation by serving as a biofilm for bacteria in patients with a UTI.³

The bladder can be filled with saline to check for leaks. Simple interrupted or cruciate sutures to seal leaks should be placed. The surgery site should be lavaged with warm sterile saline before routine closure of the abdominal wall. In male dogs, the transected preputial muscle should be sutured with a simple horizontal mattress or simple interrupted pattern.

Postoperative Considerations

Following cystolith removal, postoperative radiography (or other imaging appropriate for the stone type) should be performed to confirm complete removal of the stones from the bladder and urethra. A relatively high number of stones are left behind, even when the bladder and urethra are extensively flushed during surgery. A study found that 20% of cases had incomplete urolith removal following cystotomy.¹⁰

Urine output and appearance (eg, hematuria) should be monitored postoperatively. Intravenous fluid administration should be continued as long as blood clots continue to pass to reduce the risk for obstruction. Although blood clots can be present up to 2 weeks after surgery, most patients show improvement in urine appearance within 24 to 48 hours following surgery. Pain can be controlled with opioids perioperatively. For cats, the author uses transmucosal buprenorphine placed in the buccal pouch. NSAIDs should be administered after recovery from surgery or once azotemia has resolved and continued for 3 to 5 days for their anti-inflammatory and analgesic effects in well-hydrated patients with normal renal function. A long-lasting local anesthetic (eg, bupivacaine liposome) can be injected into SC tissue while closing if NSAIDs are unable to be administered postoperatively due to poor renal function. Antibiotics should be continued postoperatively until culture results are reviewed; pet owners should be made aware that antibiotic therapy may be adjusted pending culture results.

Complications

Complications after cystotomy are uncommon, but the patient should be monitored for dehiscence (Figure 2), infection, persistent hematuria, excessive stranguria, and obstruction (see Important Considerations for Cystotomy Closure). Hematuria and stranguria can be expected up to 2 weeks following surgery. In patients with stranguria, evaluation is needed to rule out obstruction. Dehiscence or suture line leakage is usually the result of infection, inadequately placed sutures, or increased intravesicular pressure secondary to impaired urine outflow. Dehiscence can be a life-threatening emergency in patients with uroabdomen. Hyperkalemia associated with uroabdomen should be corrected because of risk for fatal cardiac arrhythmias.³ Obstruction can occur due to remaining uroliths after surgery, highlighting the importance of postoperative imaging.^3,9

FIGURE 2 Exploration of a dog with uroperitoneum after closure of a ruptured urinary bladder with a simple continuous pattern

Important Considerations for Cystotomy Closure

Many suture patterns and techniques have been used successfully to close the urinary bladder. Essential key points to minimize complications include the following:

• The urinary bladder heals quickly, typically achieving 100% of normal strength in 14 to 21 days.^3,9

• Sutures should engage the submucosa, which is the layer of strength.^5,7,8

• Apposition results in a rapid gain in wound strength and does not reduce lumen size.⁷

• Minimal to no suture material should penetrate the lumen,^5-8 especially in patients with chronic or recurrent UTIs and possible predisposition to calculogenesis (Figure 3).⁶

• The closure must be watertight and strong enough to withstand pressures generated during micturition.⁶

FIGURE 3 Suture removed from the lumen of the bladder of a dog with a history of multiple cystotomies for cystolith removal associated with UTIs

Step-by-Step: Cystotomy

Step 1: Prepare the Patient

Position the patient in dorsal recumbency. Aseptically prepare the surgical site in a routine fashion. Swab and flush the prepuce or vulva with antiseptic solution. Drape the patient, leaving the vulva or penis accessible for catheterization.

Step 2: Make the Approach

Routinely approach the abdomen, making a skin incision (A) from umbilicus to pelvic brim. Dissect through the SC tissue (transect and tag the preputial muscle in male dogs) to the linea alba and enter the abdomen to expose the bladder (B).

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Author Insight

A self-retaining retractor (eg, Gelpi) may be used to assist in tissue retraction of the abdominal tissue if a scrubbed-in assistant is not available.

Step 3: Exteriorize the Bladder

Gently exteriorize the urinary bladder, and pack it off with moistened laparotomy sponges (A). Take care in handling the lateral ligaments, as this is where the ureters and vascular supply lie.⁹ Place stay sutures to stabilize the bladder and minimize repeated manipulations of the bladder (B).

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Author Insight

Stay sutures are most commonly placed in the apex of the bladder, but may also be placed in the neck of the bladder. Stay sutures may be attached to the surrounding drapes to maintain exposure of the bladder lumen.

Step 4: Perform the Cystotomy

Make a full thickness stab incision into the bladder lumen using a scalpel on the ventral midline in a nonvascularized area (A). Suction urine from the bladder using a Poole suction tip (B). If suction is not available, decompress the bladder via cystocentesis prior to the stab incision. Extend the incision with Metzenbaum scissors. Stay on the midline as the incision is extended caudally to avoid encroachment on the ureters as they enter the dorsolateral aspect of the bladder at the trigone (C).

Author Insight

Cystotomy should be performed on the ventral aspect of the bladder for better exposure of the trigone area.

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Step 5: Remove the Debris

Use a bladder spoon to remove obvious urinary calculi. Once all visualized calculi are removed, insert a urinary catheter in a retrograde fashion and flush the bladder with sterile saline. Flush the catheter while advancing to retropulse any urethral stones into the bladder (A). Routinely check the bladder and remove stones as necessary. Advance and flush the urinary catheter normograde to ensure a patent urethra (B).

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Author Insight

Cystoliths vary in size (C), highlighting the importance of vigorous flushing of the bladder. The bladder should be swabbed for culture and the stones submitted for analysis. Stones can be crushed into a culturette as a sample instead of swabbing the bladder for culture.

Step 6: Close the Bladder

Starting at either end of the incision, pass the suture through the serosa, muscularis, and submucosa while avoiding penetration of the mucosa (A), and close the bladder in a simple interrupted pattern (B), simple continuous pattern, or simple continuous pattern oversewn with a Cushing pattern. Leak check the bladder by using fine-tipped hemostats and probing the closure or instilling the bladder with sterile saline and monitoring for leakage. If leaks are noted, place a simple interrupted suture over the site and recheck.

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Author Insight

A monofilament absorbable suture should be used and exposure of the suture material in the bladder lumen avoided.

Step 7: Close the Abdomen

After ensuring there are no leaks, cut the stay sutures and carefully reduce the bladder into the abdomen. Close the linea alba (A), SC tissue (B), and skin (C) in a routine fashion.

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Author Insight

The preputial muscle should be sutured with a horizontal mattress or simple interrupted pattern in male dogs. A simple continuous pattern was used in (A) and (B), and a continuous subcuticular pattern was used in (C).