A Novel Technique to Intelligently Monitor and Control Renal Pelvic Pressure during Minimally Invasive Percutaneous Nephrolithotomy

Abstract

Objective: To introduce a novel technique for intelligently monitoring and controlling renal pelvic pressure (RPP) in minimally invasive percutaneous nephrolithotomy (MPCNL) and to investigate its reliability and stability. Materials and Methods: A total of 63 kidney stone patients (41 males and 22 females) were enrolled in the study. The average stone size was 3.7 ± 1.1 cm. The average age was 41.6 ± 15.6 years old. All patients underwent MPCNL under combined spinal and epidural anesthesia in prone position. A ureteral catheter connected to an invasive blood pressure monitor was retrogradely placed to measure renal pelvic outlet pressure. The MPCNL was performed with the aid of the patented device, including an irrigation and suctioning platform and a pressure-measuring suctioning sheath. On the platform, the RPP control value was set at –5 mm Hg, and the RPP warning value was set at 20 mm Hg. RPP was measured during the irrigation and suctioning period (ISP), and therapeutic period (TP) when the infusion flow was set at 300, 400, and 500 mL/min, respectively, for 5 min. Results: Sixty-three patients successfully underwent the procedure without serious complications. The mean operative time was 67 min (range 31–127 min). Three patients had residual stones >2 mm in size. No statistical significance was observed between the renal pelvic outlet pressure, platform RPP values, and RPP control values for the 300, 400, and 500 mL/min groups during the ISP and TP (p > 0.05). Conclusion: The patented devices including the platform and the sheath can reliably and stably monitor and control RPP in real time and within a safe range during MPCNL.