Podium Session 1: Endourology, BPH

Introduction: Ambulatory percutaneous nephrolithotomy (PCNL) has been proposed as a means to speed patient recovery, decrease hospital stay time, and decrease cost compared to inpatient PCNL.Studies evaluating ambulatory PCNL have used highly selective selection criteria that preclude the vast majority of PCNL candidates.The goal of our study was to perform a high-quality, randomized, controlled trial of ambulatory vs. inpatient PCNL in a representative patient population, including those with large stones (>4 cm), BMI >30, and ASA >2.Methods: This was a multicentre, non-inferiority, randomized, controlled trial of ambulatory vs. inpatient PCNL at University of Manitoba and University of California, San Francisco.Patients were randomized prior to surgery stratified for ASA, BMI, stone size, and study site.Primary outcomes were complication and readmission rates within four weeks of surgery.Secondary outcomes were stone-free rate (CT scan four weeks after surgery), quality of life (using WisQOL), and return to work time.Results: Of 70 patients (35 ambulatory and 35 inpatient), mean age was 71, 48% were BMI >30, 41% were ASA 3/4, and 31% had stone size >4 cm.Tract size was similar between ambulatory group (16 French 60%, 30 French 40%) and inpatient group (16 French 57%, 30 French 43%; p=1).There was no difference in our primary outcome of complication rate between those who underwent ambulatory (3%) and inpatient PCNL (9%, p=0.61).Readmission rate within four weeks was not different between the ambulatory (3%) and inpatient group (3%, p=1).Stone-free rate was not different between the ambulatory (71%) and inpatient group (74%, p=1).The mean recovery time in hospital after surgery was 2-3 hours in the ambulatory group vs. one day in the inpatient group.The rate of patients who were able to return to work within one week was not different between the ambulatory group (89%) vs. the inpatient group (80%, p=0.5).In those randomized to the ambulatory group, three (9%) required crossover to the inpatient group.Reasons for this were surgical for one patient (small infundibular tear that the surgeon wanted to monitor overnight), and anesthesia-related for the remaining two patients (obstructive sleep apnea monitoring, elevated potassium monitoring).Conclusions: Ambulatory PCNL has similar complication rates, stone-free rates, and readmission rates compared to those who undergo inpatient PCNL.Our results support the use of ambulatory PCNL in patients with BMI >30, ASA >2, and stone size >4 cm who have typically been excluded from consideration for ambulatory PCNL in the past.