Inclusion Criteria:  Undergoing open gynecologic surgery via a low transverse incision; Analgesic plan includes bilateral single-injection ESP blocks; and 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 eGFR ); 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; Planned intrathecal opioids; Incarceration; Known allergy to any study medication; and Any contraindication to perineural catheter insertion (e.g., infection at the catheter insertion site).