Optical triradiate nephroscope: new concept in percutaneous renal surgery.

We have been disappointed by the high residual fragment rate following electrohydraulic and ultrasonic stone disintegration during percutaneous renal surgery. As a result the optical triradiate nephroscope (Wickham/Miller, Karl Storz GmbH) has been developed to allow the extraction of calculi in the range of 0.8 mm to 1.5 cm intact. The grasping jaws of the instrument provide a vice-like grip from which the stone will not dislodge during extraction. This endoscope should be included in any basic kit for percutaneous renal surgery. It has proved invaluable both for one-stage and two-stage cases. Techniques and principles of triradiate grasping are reported.