Background and purpose: Mini-PCNL was developed to reduce the morbidity of PCNL by using smaller tract sizes. Most mini-techniques, however, require specialized instruments and use ureteroscopes as surrogates for nephroscopes, resulting in decreased visualization, poor irrigation, and difficult fragment extraction. We describe our modified technique (mPCNL) that allows for the use of standard PCNL equipment through a tract that is smaller than standard PCNL (sPCNL) but larger than previously reported for mini-PCNL.
Technique: After ureteral access with a coaxial anti-retropulsion device, the patient is placed in the prone position. After percutaneous access under fluoroscopic guidance, a 24F balloon dilating catheter is used to place a 24F Amplatz sheath. A standard 26F rigid nephroscope is used to complete the entire procedure, with the modification of selectively removing the outer sheath to allow the scope to fit in the smaller tract. Standard lithotripters and graspers are used, as necessary. ROLE IN PRACTICE: We have performed this technique on 52 patients with a mean stone burden of 19.4 mm. Overall stone-free rate was 100%, even for stones >2 cm. This technique allows for improved visualization and irrigation compared with other mini-PCNL procedures and obviates the need to purchase specialized equipment.