Repeat or Single Quadratus Lumborum Block for the Reduction of Opioid Prescriptions After Surgery in Retroperitoneal Sarcoma Patients ("RESQU-SARC" Trial)

PRIMARY OBJECTIVE: I. To use a pragmatic phase II randomized controlled trial to compare two standardized bundles of usual care for postoperative pain management to reduce the initial discharge prescription opioid volume. SECONDARY OBJECTIVE: I. To assess which pragmatic arm improves aspects of postoperative recovery including 30-day, 3-month, and 1-year opioid use, patient symptom inventory at those time points, hospital measures including length of stay and inpatient pain scores. OUTLINE: Patients are randomized to 1 of 2 arms. ARM I: Patients receive standard of care liposomal bupivacaine injection before and during surgery and standard of care non-opioids and opioids at days 0-3 after surgery in the absence of unacceptable toxicity. ARM II: Patients receive standard of care liposomal bupivacaine injection before and during surgery and standard of care non-opioids and opioids at days 0-3 after surgery in the absence of unacceptable toxicity. Patients then receive a second liposomal bupivacaine injection on day 4 after surgery. After completion of study treatment, patients are followed up at 1, 3, and 12 months after the surgery.