Tubeless PNL yields high stone-free rates, less pain

January 1, 2006

Amsterdam, Netherlands--With U.S. experience with tubeless percutaneous nephrolithotomy (PNL) now reaching 9 years, several studies have demonstrated the procedure's safety and effectiveness. Stone-free rates are similar to that seen with standard PNL using nephrostomy tubes, but postoperative hospitalization and narcotic use are decreased with the tubeless procedure, according to study results presented at the World Congress on Endourology here.

Amsterdam, Netherlands-With U.S. experience with tubeless percutaneous nephrolithotomy (PNL) now reaching 9 years, several studies have demonstrated the procedure's safety and effectiveness. Stone-free rates are similar to that seen with standard PNL using nephrostomy tubes, but postoperative hospitalization and narcotic use are decreased with the tubeless procedure, according to study results presented at the World Congress on Endourology here.

90% stone-free rate

Of the 21 renal units in 189 patients with residual stones, 15 underwent successful extracorporeal shock wave lithotripsy, four had a successful repeat PNL, one was treated ureteroscopically, and one was treated by stent placement only. Dr. Bellman and colleagues concluded that tubeless percutaneous renal surgery remains a safe and effective procedure with moderate stone burden and acceptable stone-free rates.

"An increasing number of patients have been deemed appropriate candidates for a tubeless procedure," Dr. Bellman said. "When small residual stones are found, they are usually treated with ESWL. The ureteral dilation secondary to the stent facilitates passage of small renal or ureteral stones. The additional use of Floseal in the tract allows more patients to be candidates for a tubeless procedure."

The need for ancillary procedures after tubeless PNL was also investigated by Dr. Bellman's group. This study included 180 patients who underwent 188 PNL procedures-127 tubeless PNLs and 61 standard PNLs with nephrostomy placement. In this retrospective review, 78% of patients undergoing tubeless PNL were stone free after the primary procedure, and 17% of these patients had ancillary procedures to treat residual stones. By comparison, only 41% of patients undergoing standard PNL were rendered stone free after their initial procedure, and 43% of this cohort with residual stones underwent ancillary treatment.

Standard PNL was performed in those for whom second-look procedures were planned, severe bleeding was encountered, or significant collecting system injury was noted.

"Patients who are eligible for tubeless percutaneous nephrolithotomy are unlikely to need a secondary procedure, and residual stones can most often be treated with ESWL," the group concluded.

In a prospective trial of 20 patients, the Kaiser group reported on results comparing tubeless PNL versus small-bore 8.2F nephrostomy tube placement at the end of PNL. In terms of pain scores and analgesic requirements, no significant differences were found between the two groups.

Recent research by Israeli urologists has shown, however, that analgesia requirements are reduced with tubeless compared with standard PNL. The study, presented at the WCE by Mario Sofer, MD, an assistant professor at the University of Tel Aviv, examined the feasibility of broadening the criteria for tubeless PNL based on findings during initial nephroscopy.

In a cohort of 91 patients, stone burden, multiple access tracts, supracostal access, and horseshoe kidneys were not considered contraindications. Researchers performed 42 tubeless and 49 standard PNLs. The tubeless and standard PNL groups showed similar outcomes in terms of stone burden (35 mm vs. 40 mm), complication rates (10% vs. 14%), operative time (105 minutes vs. 130 minutes), and stone-free rates without ancillary procedures (95% vs. 90%).