Clinical value of minimally invasive percutaneous nephrolithotomy in the supine position under the guidance of real-time ultrasound: report of 92 cases

To determine the clinical value of the real-time-ultrasound-guided minimally invasive percutaneous nephrolithotomy (m-PCNL) technique in the supine position, 92 patients suffering from renal or upper ureteral stones were treated by m-PCNL with a nephroscope/ureteroscope in the supine position. The ipsilateral flanks of the patients with different body sizes were elevated with a 1,000 or 3,000-ml water bag. Under cystoscopy, a ureteral catheter was inserted into the kidney. Normal saline was infused into the kidney via the ureteral catheter to dilate the entire urinary system. Under the guidance of real-time ultrasound, the needle was inserted into the urinary system to dilate the tract and establish the 16F mini-tract for percutaneous nephrolithotomy. All 92 (100%) m-PCNL procedures were successfully performed in the supine position. Primary stone clearance was achieved in 64 cases (69.6%). Residual stones occurred in 28 cases (30.4%). M-PCNL was performed for a second time in 16 cases to clear the residual stones. In 4 cases, stones remained after the second m-PCNL. Two of them were treated further by extracorporeal shockwave lithotripsy (ESWL). The total stone clearance rate of m-PCNL was 82.6%. Only one case required blood transfusion. No other serious complications occurred. The supine position is a favorable position for the patients, the surgeons and the anesthesiologists during the m-PCNL procedure. Real-time ultrasound is a valuable technique for guiding of the m-PCNL.