Staged lithotripsy may be viable alternative to PCNL

Cleveland-A staged approach to endoscopic lithotripsy may be a reasonable treatment option in patients with large renal stones who are not ideal candidates for the gold standard of percutaneous nephrolithotomy (PCNL), researchers at the University of Pittsburgh Medical Center reported. Their technique, known as staged retrograde endoscopic lithotripsy (SREL), has a slightly lower success rate than PCNL does, but it is less invasive and associated with fewer complications.

SREL is recommended for stones of 3 cm or less, according to the researchers, who noted a significant drop in stone-free rates for stones 4 cm and larger. On repeat imaging, the overall stone-free rate was 74%.

"It still doesn't compare to percutaneous surgery, which has a success rate of over 90%, but when you look at the less-invasive approach of SREL, it's an excellent approach for those patients who have comorbidities," said Daniel J. Ricchiuti, MD, a former endourology fellow at the University of Pittsburgh working under Timothy D. Averch, MD.

In the study, he and colleagues prospectively examined 23 patients with large upper tract stones who underwent SREL between 2003 and 2006. Patients were poor candidates for PCNL and were considered for the staged procedure because of comorbid conditions (primarily severe cardiopulmonary disease), obesity, advanced age, anatomic factors, or previous treatment failure.

Patients were included in the study if their renal calculus burden was >20 mm or their lower pole calculus burden was >10 mm. Mean total linear diameter of stones at the time of the initial procedure was 30.9 mm, and mean estimated total stone volume was 12,040 mm³ . All patients underwent a preoperative CT and were followed postoperatively with plain radiography or CT.

Among the 23 patients, 17 (74%) were stone free on repeat imaging. Stone-free rates dropped markedly with increasing linear stone diameter (100% stone-free rate for stones 10-20 mm vs. 40% for stones >40 mm). A similar trend was observed for stone volume, with stone-free rates of 87.5% for stones ≤15,000 mm³ and 42.9% for those >15,000 mm³ .

"Our success rate started to drop off with 3-cm stones, but it really dropped off at 4 cm. We recommend this approach for stones 3 cm and less," Dr. Ricchiuti said. "As you go up in size of stones, the number of procedures also increases."

The main drawback of SREL, Dr. Ricchuiti pointed out, is its rather cumbersome nature for both surgeon and patient. Data from the current study bear this out: The mean number of procedures was 1.5, and 10 patients (44%) required a second procedure. Mean operative time for the initial procedure was 123 minutes, and the mean operative time for two procedures was 158 minutes.

No complications occurred during the course of the study, Dr. Ricchiuti said.