AB006. The clinical efficacy of negative pressure sheath in minimally invasive percutaneous nephrolithotomy: a randomised controlled study

Background: To introduce the new-generation super-minipercutaneous (SMP) nephrolithotomy system and describe its application in practice. Methods: We described the technique of SMP in the treatment of renal stones with an emphasis on the devices, indications, technique procedure, advantages, and results. Results: The new-generation SMP endoscopic system consists of an 8 F super-mini nephroscope and a newly designed irrigation-suction sheath available in either 12 or 14 F. The irrigation-suction sheath is a two-layered metal structure. The key feature of the irrigation-suction sheath is to allow irrigation and suction respectively (the inflow through the space between the two layers of the sheath, the outflow through the central lumen of the sheath). This property could improve irrigation and stone clearance despite reduced instrument dimension. We reported our experience with this technique in adults and children. The mean stone size was 2.5±0.9 cm resulted in 39.3±29.6 min of mean operative time in adults, as well as 39.4±26.2 min for stone size of 2.1±0.6 cm in children. The initial stone-free rate (SFR) was 88.7% and 91.0% followed with a 97.2% and 95.5% of final SFR at 3 months in adults and children, respectively. No transfusions were needed in all patients. Conclusions: The new-generation SMP system is safe, feasible, and efficient for managing renal calculi less than 3 cm with advantages of a small percutaneous tract, less blood loss, high efficacy in for stone clearance and short operative time.