Continuous Erector Spinae Plane Blocks to Treat Pain Following Percutaneous Nephrolithotomy

This is a randomized, triple-masked, placebo-controlled parallel-arm human subjects clinical trial investigating the addition of a continuous erector spinae plane nerve block to a single-injection erector spinae plane block to provide postoperative analgesia following percutaneous nephrolithotomy. Participants will all receive a single-injection nerve block and perineural catheter insertion. Following surgery, participants will be randomly allocated to receive either perineural local anesthetic or normal saline until the second day following surgery.

Inclusion Criteria: * undergoing unilateral percutaneous nephrolithotomy in the prone position * analgesic plan includes a single-injection erector spinae plane block * age 18 years or older Exclusion Criteria: * morbid obesity as defined by a body mass index \> 40 (BMI=weight in kg / \[height in meters\]2) * renal insufficiency (abnormal preoperative creatinine or estimated glomerular filtration rate) * chronic opioid use (daily use within the 2 weeks prior to surgery and duration of use \> 4 weeks) * history of opioid abuse * any comorbidity which results in moderate or severe functional limitation * inability to communicate with the investigators or hospital staff * pregnancy * bilateral or multi-stage surgical procedures * incarceration * known allergy to any study medication * any contraindication to perineural catheter insertion (e.g., infection at the catheter insertion site)