Ultrasound Guidance for Renal Tract Access and Dilation Reduces Radiation Exposure during Percutaneous Nephrolithotomy

Abstract

Purposes. To present our series of 38 prone percutaneous nephrolithotomy procedures performed with renal access and tract dilation purely under ultrasound guidance and describe the benefits and challenges accompanying this approach. Methods. Thirty-eight consecutive patients presenting for percutaneous nephrolithotomy for renal stone removal were included in this prospective cohort study. Ultrasonographic imaging in the prone position was used to obtain percutaneous renal access and guide tract dilation. Fluoroscopic screening was used only for nephrostomy tube placement. Preoperative, intraoperative, and postoperative procedural and patient data were collected for analysis. Results. Mean age of patients was 52.7 ± 17.2 years. Forty-five percent of patients were male with mean BMI of 26.1 ± 7.3 and mean stone size of 27.2 ± 17.6 millimeters. Renal puncture was performed successfully with ultrasonographic guidance in all cases with mean puncture time of 135.4 ± 132.5 seconds. Mean dilation time was 11.5 ± 3.8 min and mean stone fragmentation time was 37.5 ± 29.0 min. Mean total operative time was 129.3 ± 41.1. No patients experienced any significant immediate postoperative complication. All patients were rendered stone-free and no additional secondary procedures were required. Conclusions. Ultrasound guidance for renal access and tract dilation in prone percutaneous nephrolithotomy is a feasible and effective technique. It can be performed safely with significantly reduced fluoroscopic radiation exposure to the patient, surgeon, and intraoperative personnel.

Feasibility of Retrograde Ureteral Contrast Injection to Guide Ultrasonographic Percutaneous Renal Access in the Nondilated Collecting System

“…To contextualize our findings, we can compare the results from this study to our previously published study in ultrasound-guided PCNL without contrast injection. 18 The current renal puncture time with retrograde contrast injection was 55.4 -44.8 seconds, compared with 135.4 -132.5 seconds from the previous cohort in which roughly half of patients demonstrated nondilated collecting systems. While patients from FIG.…”

“…17,18 Briefly, a 10F fascial dilator was inserted over a guide wire and then substituted with a high-pressure balloon for tract dilation. Nephroscopy was performed with a 20.8F rigid offset nephroscope, and stone fragmentation was accomplished using a Cyberwand dual ultrasonic lithotripter system (Olympus America, Center Valley, PA).…”

“…In particular, for the hydronephrotic collecting system, B-mode ultrasound-guided renal access has been shown to be safe and easy to learn. 10,18 Adding on the expense and extra step of retrograde contrast injection may provide little benefit for these patients. While we have demonstrated that utilizing this technique in the nondilated collecting system may decrease the time for renal puncture, ultrasound contrast remains relatively expensive compared with iodinated contrast.…”

X-ray–free Ultrasound-guided Percutaneous Nephrolithotomy: How to Select the Right Patient?

“…We have previously published details regarding surgical technique. 8,13 Before moving the patient to a prone position, we placed a 5-French externalized ureteral catheter into the ipsilateral ureter via a flexible cystoscope for retrograde instillation of saline to dilate the kidney as needed. We used a 3.5-MHz convex abdominal transducer (Hitachi Aloka Medical America, Wallingford, CT) to localize the stone position as well as the collecting system anatomy.…”

“…6 Whereas this technique has been widely used in China, 7 adoption has only recently gained popularity in the United States.We have successfully implemented US guidance for PCNL at our institution since May 2014. 8 As urologists move toward adopting US guidance, the following question arises: which patient is best for initiating their US experience? The purpose of this study is to identify perioperative factors influencing the success of US-guided PCNL for each step of the procedure.…”