Ambulatory percutaneous nephrolithotomy is safe and effective in extended criteria patients

ABSTRACT

Introduction & Objective: Ambulatory tubeless percutaneous nephrolithotomy (aPCNL) has been shown to be safe and effective in highly selected patients. However, these selection criteria preclude the vast majority of patients that undergo PCNL. The objective of our study was to compare complication and stone free rates after aPCNL in standard selection criteria vs. extended criteria patients. Methods: Retrospective review of prospective data on all patients who underwent aPCNL at one academic center from 2007-2018. Extended criteria patients were defined as any Age >75 years, BMI >30 kg/m2, ASA >2, bilateral stones, solitary kidney, staghorn calculi, stone burden >40 mm, multiple tracts, or prior nephrostomy tubes/stents. Primary outcomes were complication rates (Clavien-Dindo classification) and stone free rates (no fragments >/ = 3 mm). All patients were discharged with a ureteric stent and no nephrostomy tube after meeting discharge criteria which included hemodynamic stability, no fever, and no significant pain. Results: We identified 118 patients of which 92 (78%) met extended criteria. Mean BMI was 31 kg/m2 and 45% were ASA 3 or higher. Mean sum maximum stone diameter was 24 mm. Multiple stones were present in 25%, bilateral stones in 7%, staghorn stones in 4%, and pre-existing tubes/stents in 4%. There was no difference in complication (12% vs. 18%, p = 0.56), Emergency department visit (12% vs 18%, p = 0.56), or readmission (4% vs. 5%, p = 1) rates between standard and extended criteria patients respectively (Table 1). Of the complications, 85% were Clavien-Dindo grade 1. Stone free rates were not different between standard (84%) and extended (83%) criteria patients (p = 1). No extended criteria variables were associated with complications in univariate analysis. Stone burden >40mm (OR 5.8, 95% CI 1.4-25.2, p = 0.018) and multiple tracts (13.1, 95% CI 1.1-154.7, p = 0.041) were associated with residual stone fragments. Conclusions: Complication and stone free rates were not different between standard and extended selection criteria patients undergoing aPCNL. This data supports the safety and efficacy of aPCNL in patients using extended selection criteria. As the COVID-19 pandemic continues to strain hospital resources, aPCNL offers a solution to deal with a growing backlog of patients with complex stone disease.