High-Power Holmium Laser Percutaneous Nephrolithotripsy for Large Staghorn Stone

Abstract

Purpose: To investigate the safety and efficacy of high-power holmium laser (70 W) in percutaneous nephrolithotripsy (PCNL) for large staghorn calculi. Materials and Methods: From December 2004 to March 2008, 438 consecutive patients (456 renal units) with large staghorn stones (diameter ≥4 cm) underwent PCNL with a pulsed holmium:YAG laser using a 1000-μm end-firing optical fiber. For the first 106 patients, a 30 W (3.0 J/pulse and 10 pulse/s) holmium:YAG laser was used for the management of renal stones, whereas for the other 332 patients (Group B), the laser power was set at 3.5 J/pulse with a frequency of 20 pulses/s. For stones in a calyx that were visible with a nephroscope, but unreachable with laser during lithotripsy, the renal mucosa of the calyx was split with 100 W holmium laser to further fragment the stones. Moreover, a porcine mode for the safety of high-power holmium laser was developed. Results: The average stone size was 5.6±0.8 cm in Group A and 5.8±0.8 cm in Group B. All of the patients in both groups had successful PCNLs. The average lithotripsy time in Group B was significantly shorter than that in Group A (44+11.5 minutes vs. 69±14.8 minutes, p>0.05). No patient had a severe complication. In addition, a total of 39 patients underwent calyx splitting, and no hemorrhage happened during and after operation. For patients undergoing 70 W high-power holmium laser, the GFR of operated kidney re-examined 6 months after operation improved greatly after operation than before (45.12 vs. 31.91 mL/min, p>0.05). Pathological evaluation of porcine kidneys exposed to laser firing showed no renal damage of high-power holmium laser. Conclusions: The high-power holmium:YAG laser enhances the lithotripsy efficacy by vaporizing and bursting the renal stone quickly and reduces the lithotripsy time significantly. The high-power holmium:YAG laser percutaneous nephrolithotomy is an effective and safe treatment for patients with large renal stones. No competing financial interests exist. Runtime of video: 3 mins X. Gao, T. Zhou and C. Yang have contributed equally to this work.