Challenging stones: Size, location data, skills are key

Q: How would you define a "challenging stone"?

Q: What types of information and skills do urologists need to treat these cases?

Q: Is there some level of experience that you would recommend for urologists treating challenging stones?

Q: What kind of additional training would you recommend?

A: One needs to be fairly adept in all the endoscopic procedures: ureteroscopy, both flexible and semi-rigid, as well as percutaneous approaches. That involves being able to access the kidney adequately, either with the help of a radiologist or under the direction of a urologist, and the use of rigid and flexible scopes in the kidney.

Q: What are the key technologies that a urologist should have at his or her disposal to treat these challenging stones?

A: Flexible endoscopy is probably the key to any challenging case. Flexible endoscopy gives you flexibility, so to speak. It allows you to access sites that are remote from your point of entry, and that can be the factor separating those who are able to treat the stone and those who aren't.

Q: In terms of treatment technologies, are there any specific adjuncts that are critical?

A: The more adjuncts you have at your disposal, the greater flexibility you have in being able to accomplish treatment of the stone. A Holmium laser is essentially the minimum instrumentation required for any challenging stone because you must have a reliable means for fragmenting a stone, regardless of its composition.

You also need to have instrumentation that will allow you to access the stone, fragment it, and remove the fragments. There are any number of adjunct devices and instruments to accomplish that. Ureteral access sheaths not only facilitate access to a stone, but also improve visibility and increase safety by lowering intrarenal pressures. A variety of devices that are used to displace or move a stone or retrieve fragments are critical, and that may require a number of choices as well. In some cases, a basket may be the most appropriate means of displacing a stone. In other cases, it may be safer to use a reversible device, like a grasper.

If the intention is to remove a fragment from the kidney or ureter and remove it through the ureter, then a reversible device like a wire-prong grasper and basket are advisable because these devices will always let go of a fragment before avulsing the ureter. If the intention is to displace a stone within the kidney to facilitate fragmentation or to remove it percutaneously, a basket is usually the most expeditous instrument.