There is something gratifying about doing a cystotomy and removing uroliths from the bladder. I do fewer these days now that we have dietary options that can dissolve most stones, but from time to time, a cystotomy becomes necessary. This was the case for Fender, a morbidly obese 14-year-old neutered male pug, who had been on months-long courses of antibiotics. Despite dietary management and urinary cultures, the infection persisted.
Weighing in at 19.2 kg, he was probably the largest pug I had ever seen, and the thought of urinary bladder surgery on such an old and obese dog was not one I was looking forward to. With borderline high kidney function, his age and his degree of obesity, he was given an American Society of Anesthesiology (ASA) risk of three, thus necessitating an anesthetic period that needed to be as short as possible.
I generally exteriorize the bladder through an abdominal incision to thoroughly explore for uroliths. I knew it was going to be a challenge; both because it was a male dog and because there was so much abdominal fat; even with a generous abdominal incision, I would not be able to see much. In this case, I used a technique I have done in the past for heavy dogs, suturing a portion of the bladder onto the edges of the abdominal incision. This allows for a much smaller opening in the abdomen. It also prevents spillage from urine, stones, or a saline flush from entering the abdomen.
Fender was sedated with 0.4 ml of dexmedetomidine at 0.5 mg/ml and 0.7 ml of hydromorphone at 2 mg/ml. He was then given propofol intravenously to the point where he could be intubated, in this case, 3.2 ml of a 10mg/ml concentration. After intubation, he was maintained on sevoflurane at various concentrations, adjusting, as necessary. A line block was made over the proposed incision site using 1.5 ml of 2 percent bupivacaine.
The step-by-step process
The first step is to choose an area over the bladder, which in a male dog means moving the penis to one side in order to access the linea alba and make the incision. The bladder is then moved up to “fill” the incision and then it is sutured at the top and bottom of the incision and on both sides to stabilize it (Figure 1). I used a 3-0 monofilament suture to pass through the outer muscular layer of the bladder and through the skin. More than four sutures could be used if needed to stabilize the bladder to the abdominal opening.
The second step is to make an incision in the bladder wall and explore for stones (Figure 2).
The next step is to thoroughly flush the bladder with sterile saline to remove any remaining stones that cannot be felt by palpation or exploration (Figure 3).
The bladder is then closed in the usual manner. In this case, it is closed by using a 3-0 monofilament absorbable suture in a continuous pattern for a tight seal. This is done in two layers. The first layer is in the bladder mucosa, being careful none of the suture is within the lumen of the bladder where it can become a nidus for infection. The second layer is placed in the outer muscular layer of the bladder (Figure 4).
The abdomen is then closed using a monofilament absorbable suture in the internal layers, and polyethylene sutures in the skin. As you can see in Figure 5, the entire surgery was performed through a 5-cm long incision.
The advantages of this technique are that the incision size is minimal, a mostly tight seal is made so nothing can enter the abdomen, and a shorter incision means less pain post-operatively. Perhaps more important for this obese and geriatric patient, it also means less time under anesthesia. The disadvantage is the entire bladder cannot be manually palpated for the presence of stones. Instead, we must rely on “feeling” for the uroliths using metal instruments, and thoroughly flushing the bladder with saline to look for any stones that are too small to find by exploring.
An additional step not shown here is to also pass a catheter up from the exterior opening of the urethra while flushing with saline to make sure no stones are within the proximal portion of the urethra where it is wider and may harbor a urolith.
Michael Petty, DVM, is a graduate of the veterinary school at Michigan State University. As the owner of Arbor Pointe Veterinary Hospital and the Animal Pain Center in Canton, Michigan, he has devoted his professional life to the care and well-being of animals, especially in the area of pain management. Dr. Petty is the past president of the International Veterinary Academy of Pain Management. A frequent speaker and consultant, he has published articles in veterinary journals and serves in an advisory capacity to several pharmaceutical companies on topics of pain management. Petty has been the investigator/veterinarian in 12 FDA pilot and pivotal studies for pain management products. He has lectured both nationally and internationally on pain management topics.