New polymer, robotics head advances in ureteroscopy

March 1, 2009

The World Congress of Endourology & SWL proved to be a fertile platform for technological advancements in ureteroscopy. Three studies in this area were particularly noteworthy.

Shanghai, China-The World Congress of Endourology & SWL proved to be a fertile platform for technological advancements in ureteroscopy. Three studies in this area were particularly noteworthy.

Thirteen patients underwent ureteroscopic stone fragmentation combined with administration of the BackStop polymer. Twelve were stone free after one sitting, and in only one patient did the stone migrate through the gel. The polymer was effectively irrigated out of the ureter at the end of all procedures, leaving no residual occlusion. The surgeons rated the visibility as good but said the polymer can be difficult to see.

Dr. Rane and colleagues are trial investigators for Pluromed.

Another advance that has become an integral part of endourology is the application of robotic technology, and Cleveland Clinic urologists have begun exploring the incorporation of robotics into ureteroscopy. Co-author Monish Aron, MD, a clinical faculty member in advanced laparoscopic urology, presented Cleveland Clinic's initial clinical experience with flexible robotic ureteroscopic laser lithotripsy (Hansen Medical, Mountain View, CA). This abstract was awarded Best Overall Paper at the World Congress.

The device is based on a flexible robotic catheter system originally designed for robotic cardiac catheterization. A total of 18 patients, mostly with lower pole renal calculi, were enrolled and underwent robotic ureteroscopy. Patients had a mean stone size of 11.9 mm, and total mean operative time was 91 minutes (of which 41 minutes was robotic console time). The surgical team rated stone localization as 8.3, maneuverability as 8.5, and stone fragmentation as 9.2 on a visual analog scale of 1 to 10, with 10 being best. At 3 months follow-up, 89% of patients were stone free based on intravenous urogram.

"Some of the advantages may be the ease of maneuverability, the stability of the platform, and surgeon ergonomics," said Dr. Aron, who worked on the study with Inderbir Gill, MD, and colleagues.

"One of the biggest advantages is the ability for the surgeon to minimize fluoroscopic exposure. Certainly, the major question is the cost."

Co-authors Mihir Desai, MD, and Dr. Gill are consultants and stockholders with Hansen Medical.

A collaborative effort from the University of Michigan, Ann Arbor, and the University of British Columbia, Vancouver investigated the treatment of chronic flank pain associated with papillary calcifications by laser endopapillotomy. They performed a retrospective review of patients who underwent ureteroscopic intervention and reported on the success rates and durability of laser ablation.

The cohort consisted of patients without free collecting system stones and who had a non-colicky, chronic backache with the only radiographic finding being papillary calcification. A total of 62 patients were identified, 61% of whom had multiple procedures, for a total of 164 ureteroscopies. Although only 48 patients had adequate follow-up, 84% of those treated reported significantly less pain.

The report documented a durable response of 26 months, with 60% of patients in remission for greater than 1 year. The authors conclude that laser endopapillotomy is an effective and safe treatment for chronic flank pain associated with calcified papillae.