Ultrasound-Guided Mini Percutaneous Nephrolithotomy with Suction Sheath.

Abstract

The mini percutaneous nephrolithotomy (PCNL) is a mainstay in the treatment of kidney calculi, particularly in case of >2 cm kidney stones, large lower pole stones, large impacted proximal ureteral stones, and residual stones after failed extracorporeal shockwave lithotripsy or retrograde intrarenal surgery. An accurate renal access represents a fundamental part of the procedure, modalities to guide the percutaneous tract preparation include ultrasound, fluoroscopy, or their combination. Both ultrasound and fluoroscopy offer several advantages and some limitations. The combined utilization of ultrasound and fluoroscopy is less adopted nowadays; however, this strategy has its merits particularly in cases where the puncture can be problematic with one imaging modality alone. Ultrasound can easily identify the posterior renal calix and surrounding visceral structures, although some situations such as obese patients, undilated collecting system or complex stones may represent a challenge. Intracaliceal blood clots and air may reflect ultrasound, reducing significantly the image quality. Therefore, the assessment of the intrarenal anatomy, the stone identification, and the ability of guiding the needle during access may decrease significantly, particularly in cases with complex stones, when multiple tracts are required. In these cases, fluoroscopy could determine the relationship between the angle and depth of the puncture needle and the target calices by rotating the C-arm to help the needle puncture and tract dilation. Therefore, the benefits of dual guidance would be beneficial during PCNL. In addition to an improved accuracy of puncture and dilation, the combined approach improves the detection of residual stones, facilitating the achievement of a stone-free state. Herein we describe our experience with this technique, describing surgical steps and troubleshooting tips of mini-PCNL in the accompanying video. Further high-quality studies are needed to demonstrate the advantages of combined utilization of ultrasound and fluoroscopy during PCNL and its optimal indications.