Surgeon’s Corner: Cystotomy & Scrotal Urethrostomy

Presentation

A 5-year-old male dachshund presented with stranguria secondary to cystourethrolithiasis. Urinary obstruction prevented retrograde urinary catheterization.

Surgery

The patient is positioned in dorsal recumbency and the caudal abdomen, prepuce, and scrotum prepared for aseptic surgery. The caudal abdomen is draped for cystotomy if needed, as was the case in this patient. Skin incision is made in the caudal abdomen and paramedian to the penis using an electrosurgical apparatus or a scalpel. The SC tissue is dissected sharply to the level of the linea, and the linea is then incised. The apex of the bladder is grasped with DeBakey forceps and monofilament stay suture placed. Gentle cranial traction applied to the suture allows visualization and manipulation of the bladder. Two more stay sutures are placed on either side of the planned cystotomy site in the ventral midline of the bladder. Using an army-navy retractor, an assistant can retract the caudal extent of the abdominal incision to further provide visualization and exposure of the bladder. The bladder is packed off with sterile sponges, and a small stab incision is made using a #15 scalpel blade. Urine leakage is controlled using the sponges and in-house suction. It is important to avoid the large cranial and caudal vesicular vessels that course over the bladder while making the cystotomy incision. The incision is extended with Metzenbaum scissors, and a small sample of bladder mucosa is collected for culture and susceptibility testing. Bladder stones are removed using a gallbladder spoon.    

A red silicone rubber catheter is placed normograde, as urinary obstruction prevented retrograde urinary catheterization in this patient. The catheter aids in isolating and protecting the scrotal urethra during dissection. An elliptical incision is made around the base of the scrotal skin, being careful to leave enough skin to avoid tension on the urethrostomy. The SC tissue is transected and the retractor penis muscle retracted laterally, exposing the scrotal urethra.  The surgeon’s nondominant hand is used to stabilize the scrotal urethra. With the urinary catheter in place, a scalpel is used to make a roughly 2.5- to 3-cm incision through the ventral midline of the scrotal urethra. It is important to remember that some degree of contraction of the urethrostomy site will occur postoperatively, possibly up to 50% contraction in some patients.¹ The scrotal urethra is the preferred location for urethrostomy in dogs, as it is superficial, of larger diameter, and less vascular than other regions of the urethra.² Although it is less vascular, brisk bleeding is still expected during the procedure but typically resolves with progressive placement of sutures. The urethra is sutured to the skin circumferentially using 4-0 or 5-0 monofilament suture on a fine taper-point needle in a simple interrupted pattern. A continuous pattern is also acceptable but is more challenging for the novice surgeon. Sutures are passed via the uroepithelium and, in split-thickness fashion, through the dermis, which prevents eversion of SC tissues and creates accurate apposition, minimizing the risk for urine dissection into the SC space.

After scrotal urethrostomy, the bladder is flushed liberally normograde and retrograde via the urethrostomy site and the bladder is evaluated to check for residual stones. After all stones have been removed, the cystotomy is closed in a single-layer simple continuous pattern, again using a fine taper-point needle. Every effort is made to engage the submucosa without penetrating the bladder lumen; however, with appropriate suture selection (the author prefers poliglecaprone or glycomer), the risk for development of a calculus nidus is very small. The caudal abdomen is lavaged and suctioned. The linea, SC tissue, and skin are closed routinely.

Outcome

This patient recovered with minor, but expected, stoma hemorrhage during the initial 48 hours and was able to urinate immediately following surgery (it was unnecessary for a urinary catheter to remain in place). Before patient discharge, a firm plastic Elizabethan collar was placed, with owner instructions to strictly maintain the collar at all times until the postoperative recheck evaluation by the surgeon at 14 days.

In appreciation of Alternatives Research and Development Foundation and University of Florida School of Veterinary Medicine for supporting development of this video.

Surgeon’s Corner is intended as a forum for those with specialized expertise to share their approaches to various techniques and procedures. As such, the content reflects one expert’s approach and is not subject to peer review.