A Multicenter Randomized Controlled Trial of Ambulatory Versus Inpatient Percutaneous Nephrolithotomy

Ambulatory percutaneous nephrolithotomy (PCNL) has been proposed as a means to speed patient recovery and decrease cost compared with inpatient PCNL. The objective of our study was to perform a high-quality randomized controlled trial of ambulatory versus inpatient PCNL.

A multicenter noninferiority randomized controlled trial of ambulatory versus inpatient PCNL was conducted at Health Sciences Centre Winnipeg, and University of California, San Francisco Medical Center. Patients were randomized prior to surgery, stratified based on American Society of Anesthesiologists (ASA) status, body mass index (BMI), stone size, and study site. The primary outcome was complication rates within 4 wk of surgery.

Of 70 patients (35 ambulatory and 35 inpatient), 48% had BMI >30, 41% had ASA 3/4, and 31% had stone size >4 cm. Complication rates were 6% in the ambulatory and 14% in the inpatient group (risk difference -8%, 95% confidence interval [CI] -22% to 5%, p = 0.4). The readmission rate was 6% in the ambulatory versus 3% in the inpatient group (risk difference 3%, 95% CI -7% to 12%, p = 0.6). The stone-free rate was 77% in the ambulatory versus 71% in the inpatient group (risk difference -6%, 95% CI -27% to 15%, p = 0.6). In a multivariable analysis, we did not see evidence of inferiority of ambulatory PCNL compared with inpatient PCNL for complications (odds ratio [OR] 0.49, 95% CI 0.12-1.94, p = 0.3) or residual stone fragments (OR 1.46, 95% CI 0.44-5, p = 0.5). Limitations include a somewhat low sample size.

We did not see evidence of inferiority of ambulatory PCNL compared with inpatient PCNL for complication rates, stone-free rates, readmission rates, or quality of life. Our results support the use of ambulatory PCNL at experienced centers.