Impact of Stone Density on Percutaneous Nephrolithotomy Outcomes with a Dual Frequency Ultrasonic Lithotripter: Computerized Tomography Based Outcomes at a Low Volume Center.

Introduction: We studied the safety and efficacy of the CyberWand™ lithotripter and how stone density affects the efficacy.

Methods: We retrospectively analyzed the outcomes of percutaneous nephrolithotomy performed using the CyberWand dual frequency ultrasonic lithotripter at our institution between November 2009 and July 2015. A total of 63 procedures were performed on 57 renal units and, thus, we may be considered a low volume center. We assessed the outcomes of each renal unit in terms of the clinically insignificant residual fragment rate, complication rate, operating room time, estimated blood loss and length of hospitalization. We evaluated the effect of HU of the stone (less than 1,000 HU considered soft and greater than 1,000 HU considered hard) on outcome.

Results: Our outcomes using the CyberWand lithotripter were comparable to those of other lithotripsy modalities in terms of the complication rate and clinically insignificant residual fragment rate. We achieved clinically insignificant residual fragment status (defined as less than 4 mm residual stone size) in 54% of renal units and the overall complication rate was 24%. There were no appreciable differences between soft stones and hard stones in terms of any outcome parameter including complication rate, clinically insignificant residual fragment rate and operative time.

Conclusions: The CyberWand lithotripter is an acceptable, noninferior modality of percutaneous lithotripsy of renal calculi. The efficacy of the CyberWand lithotripter is not affected by stone density.