Lithotripsy

What is lithotripsy?
Lithotripsy is an endoscopic procedure to fragment and remove stones from the bladder and urethra. A special laser, called a holmium laser, is used to break up the stone and endoscopy is needed to get the laser right up to the stone where the patient’s tissues are not in the way.

The cystoscope is used in the urinary tract to penetrate the very narrow urethral opening of a small animal. Once the cystoscope is in position, the laser uses heat to create water vapor bubbles, which rapidly expand and collapse. If these bubbles are in contact with the stone, the crystal structure of the stone is disrupted and the stone fragments. The fragments are either allowed to pass or are removed via basket with the guidance of the cystoscope.

This differs from extracorporeal shock wave lithotripsy in which sound wave energy is directed toward stones while animals lie in a water bath.

If the stone is in the urethra, disruption of the stone is easiest. Despite potential problems, studies have reported 83-96% success (i.e. complete stone removal) in female dogs and 68-81% success in male dogs. Laser lithotripsy is an excellent option for dogs with urethroliths or a few small cystic uroliths than can be repositioned into the urethra prior to laser fragmentation.

Why consider laser lithotripsy?
Laser lithotripsy offers an alternative to traditional surgery or medical dissolution (when possible) as treatment for removal of urinary stones (bladder and urethra). It is considered minimally invasive when compared to surgery.
Laser lithotripsy is thought to be as effective surgery in removing stones. It is estimated that incomplete stone removal occurs in approximately 20% of surgical stone removal cases2 versus
8% via lithotripsy.1

Which patients are good candidates for laser lithotripsy?
Patients with urethral or bladder stones that:
Female dogs or cats that weigh a minimum of 7 lb.
Male dogs that weigh a minimum of 20 lb (or if a 10 Fr red rubber catheter is able to be passed through the urethra).

Which patients are not good candidates for laser lithotripsy?
Female dogs with multiple large bladder stones.
Male dogs with multiple urethral and bladder stones.
Male cats - Not possible to perform in any male cats.
Ureteral or kidney stones - Not possible to perform in any of these stone types.

Will my pet be anesthetized for the procedure?
General anesthesia is required for cystoscopy and lithotripsy as this will provide comfort, pain control, and prevent any movement during the procedure.

Is it painful?
The procedure is minimally invasive and nonpainful. However, the manipulation of the cystoscopy to remove the stones triggers more inflammation and possibly leading to difficulty urinating after the procedure.

What are the benefits?
Minimally invasive
Less pain
Shorter recovery time
Minimal scarring

Are there alternative procedures?
Alternative procedures include surgical removal and possibly urohydropulsion (in large female dogs with very small stones).

How can we measure results? Will the stones come back?
Radiographs or fluoroscopic images will be obtained prior, during and, after the procedure to ensure that all stones have been removed. Recurrence rate will depend on primary cause of stone formation and individual predisposition to more stone formation.

How long is the recovery?
Recovery typically occurs over 1-7 days depending on the size of the stones, prior inflammation, and size of the patient. Some hematuria and dysuria may be noted within the first week. Depending on the severity of the changes seen during cystoscopy, pre-emptive urinary cauterization may be recommended to help the urethra heal.