Effect of Local Infiltration of Liposomal Bupivacaine on Postoperative Analgesia in Patients With Craniotomy Microvascular Decompression

Background: Approximately 60-84% of patients undergoing craniotomy experience moderate to severe pain within 48 hours postoperatively, with posterior fossa craniotomy patients experiencing more severe pain. Microvascular decompression (MVD) is a type of posterior fossa surgery. Traditional analgesic regimens rely on intravenous opioids, but these have significant side effects. Currently, local infiltration at the incision site is a simple and effective analgesic method in multimodal analgesia protocols after craniotomy. Liposomal bupivacaine (Exparel®) is a new type of sustained-release local anesthetic. Its liposome encapsulation technology can extend the drug release time to 72 hours, covering the entire time window of postoperative acute pain and helping patients better control pain.

Objective: This study aims to explore the efficacy of local infiltration of liposomal bupivacaine at the scalp incision in acute pain after microvascular decompression in neurosurgery and provide evidence for clinical practice.

Methods: This study is a single-center, prospective, randomized controlled trial. A total of 100 patients scheduled for elective craniotomy for microvascular decompression will be enrolled. They will be randomly assigned to the liposomal bupivacaine incision infiltration group (LB group) or the conventional treatment control group (C group). After induction of general anesthesia, in the LB group, after preoperative disinfection and draping, the surgeon will perform layer-by-layer infiltration of the incision (subcutaneous → muscle → periosteum) before skin incision. In the C group, the routine procedure of direct disinfection and draping followed by skin incision will be performed. Both groups will receive standardized multimodal analgesia after returning to the ward. The primary outcome measure is the area under the curve of the numerical rating scale (NRS) for rest pain from 0 to 72 hours postoperatively (AUC NRS-R0-72). Secondary outcome measures include the time to first analgesic request within 72 hours postoperatively; rescue analgesia within 72 hours postoperatively (opioid analgesics converted to morphine milligram equivalents); NRS scores at 6, 12, 24, 48, and 72 hours postoperatively; hemodynamic data: heart rate and blood pressure at skin incision, 1 hour after skin incision, 2 hours after skin incision, at the end of surgery, and 1 hour postoperatively; QoR-15 score at 72 hours postoperatively; and length of hospital stay and hospitalization costs.