Background and purpose: Precise needle puncture of the renal collecting system is an essential step for successful percutaneous nephrolithotomy (PCNL). Puncture is technically challenging and has many pitfalls for the urologic surgeon. We describe the development of a novel navigation system, the Locator, to assist accurate percutaneous needle placement and compare this with conventional manual techniques.
Materials and methods: The essence of the device is that it stabilizes the needle for PCNL puncture. It relies on an adjustable lockable multidirectional head that is securely fixed to the operating table. The radiolucent head holds a 10F metal guide that allows renal collecting system puncture. The system uses the traditional fluoroscopic "bull's-eye sign" to achieve precise and fixed alignment. Objective assessment was obtained by in vitro testing using simulated PCNL puncture with and without using the Locator. Time to successful puncture and fluoroscopy screening time (FST) was assessed.
Results: Six urologic trainees were recruited to test the Locator. Simulated PCNL puncture was quicker and with reduced fluoroscopy when the apparatus was used. The mean FST for traditional hand vs Locator puncture was 46 vs. 16 seconds (P = 0.03), and the mean time to puncture was 225 vs. 118 seconds (P = 0.26).
Conclusion: The Locator is a simple, cheap, and novel assistant to achieving successful PCNL puncture. It achieves this by stabilizing the needle during puncture. Preliminary in vitro testing suggests that the device may reduce fluoroscopy exposure and be quicker. The device warrants further evaluation in the clinical setting.