Tubeless PNL, alpha-blockers find expanded roles in stone disease

August 15, 2007

Among the studies presented at this year's AUA annual meeting, Glenn M. Preminger, MD, considered these to be among the most noteworthy presentations in the field of nephrolithiasis.

Key Points

Dr. Preminger, professor of urologic surgery at Duke University Medical Center, Durham, NC, explained the clinical significance of this research in an interview with Urology Times.

Tubeless percutaneous nephrolithotomy (PNL) is resolving an expanding number of clinical situations to include the supracostal approach.

The second study, from the R.G. Stone Urological Research Institute in Mumbai, looked at 168 patients undergoing supracostal tubeless nephro lithotomies between 2004 and 2006, and concluded that a tubeless supracostal approach was a safe procedure that reduced analgesic use and hospital stay. However, the authors noted that it was associated with bothersome stent symptoms in nearly half (46.2%) of the procedures, an observation Dr. Preminger also made. He pointed out that the indications for percutaneous tubeless nephrolithotomy have been expanding since Gary Bellman, MD, of Kaiser Permanente in Los Angeles, began to explore the procedure more than 10 years ago.

"The driving concept behind the tubeless PNL approach procedures is reduced patient morbidity following stone removal. These studies are showing that you can use the tubeless procedure in almost anyone," Dr. Preminger said.

"What we need are studies that identify clinical presentations in which the tubeless procedure would be contraindicated. There are undoubtedly cases in which the tubeless procedure should not be used, but, for the time being, one should consider a tubeless approach in the majority of patients needing percutaneous nephro lithotomy."

Alpha-blockers help resolve stent-related pain and irritative symptoms and reduce analgesic requirements.

A study from the Dongguk University Medical Center in Kyungju, Republic of Korea, showed that alpha-blockers relieved symptoms associated with internal stents. Patients receiving the alpha-blocker alfuzosin (Uroxatral), 10 mg daily; phloroglucinol, 240 mg; or placebo were compared to show that those on the alpha-blocker demonstrated improvements on the visual analog pain scale and the International Prostate Symptom Score (IPSS), including IPSS subscales for urgency, nocturia, and quality of life.

Dr. Preminger noted that the relief provided by the alpha-blocker stemmed from its mechanism of action, rather than any analgesic properties.

"The concept is that the blocker works physiologically to relax the ureter, subsequently reducing morbidity resulting from the stent," he explained. "The same mechanism is thought to facilitate stone passage when the agents are used for this purpose. We need one or more large randomized, prospective trials to help define those patients who would receive the greatest benefits from these agents."

Digital ureteroscopes provide sharper, better-lit images of operating fields. Now they need to become smaller.

Several presentations wowed the audience with the clarity of images provided by new digital endoscopes in which the charge-coupled device (CCD) is incorporated directly into the scope. Operating fields appeared in balanced light and were magnified with no loss of detail.

"It is hard to imagine that it was only 1985 when we started attaching cameras to our endoscopes," Dr. Preminger said. "There have been dramatic advances in imaging technologies associated with both rigid and flexible scopes.