Laser Lithotripsy of Canine Bladder and Urethral Stones

Laser lithotripsy is equally as successful as traditional surgery for removing stones from female dogs. The main benefit of lithotripsy is that the procedure does not require an incision, which typically results in a faster recovery time for the patient.

To date, the Veterinary Teaching Hospital's Small Animal Internal Medicine team has achieved a 100% success rate in removing stones from the urethra of male dogs. The typical success rate for removing bladder stones from male dogs, however, is less than  female dogs because of the smaller size of the male urethra and its more complex urethral shape. As such, some dogs are not considered good candidates for laser lithotripsy:

1. Male dogs less than 15 pounds: The endoscope may be too large to traverse the urethra.
2. Male dogs with more than two bladder stones greater than 5 mm in diameter (depending on the size of the dog)
3. Female dogs whose entire bladder is full of stones greater than 5 mm in diameter
4. Dogs with uncontrolled urinary tract infection: Once infection is controlled, lithotripsy can be considered.

The length of the lithotripsy procedure is dependent on the size and number of stones and the patient's size. A visit to our hospital for this procedure will proceed as follows:

1. The patient is evaluated on day one.
2. Lithotripsy is performed on day two. Dogs with urethral obstruction will have laser lithotripsy performed more expeditiously.
3. The patient is recovered and discharged when appropriate, which results in a two-day, one- or two-night hospital stay.

The lithotripsy procedure includes the following steps:

1. The patient undergoes general anesthesia and rigid (female) or flexible (female or male) cystoscopy is performed.
2. A laser fiber is passed through the endoscope, placed in contact with the stone, and Holmium:YAG laser energy is then applied causing fragmentation.
3. The procedure is repeated until all stone fragments are small enough to be extracted via endoscopic baskets or voiding urohydropulsion.

Calcium oxalate, struvite, urate, and cystine stones are all susceptible to laser lithotripsy.

Thermal injury to the bladder/urethral mucosa is possible, but risk is minimal as the laser energy only penetrates less than 1 mm. Urinary tract penetration with the laser fiber or cystoscope is rare, but possible. Urethral edema with subsequent stranguria or obstruction is possible. The inherent risk of anesthesia is present.