Effect of Intrathecal Morphine on Quality of Recovery After Laparoscopic Gynecological Surgery

Overview

Minimally invasive gynecologic surgery has become the standard approach for the treatment of benign and malignant gynecologic diseases, offering the advantages of reduced surgical trauma and faster recovery. However, postoperative pain remains a major barrier to optimal recovery, with up to 40% of patients experiencing moderate to severe pain within the first 24 hours after laparoscopic procedures. Laparoscopic gynecologic surgery typically induces both somatic pain from abdominal wall incisions and visceral pain caused by peritoneal traction and pneumoperitoneum, making effective analgesia challenging. Transversus abdominis plane block (TAPB) is commonly used to control somatic incisional pain but provides limited relief of visceral pain, often resulting in increased opioid consumption and opioid-related adverse effects such as dizziness and postoperative nausea and vomiting. Intrathecal morphine (ITM) offers potent and long-lasting visceral analgesia with minimal systemic opioid requirements and has demonstrated safety and efficacy across multiple surgical settings. The complementary analgesic mechanisms of TAPB and intrathecal morphine suggest that their combination may enhance postoperative recovery by improving pain control while reducing opioid use. The objective of this randomized controlled trial is to evaluate whether the combination of intrathecal morphine and TAPB improves the quality of recovery after laparoscopic gynecologic surgery compared with TAPB alone. This study aims to provide high-quality clinical evidence to guide the development of an optimized multimodal analgesia strategy for patients undergoing minimally invasive gynecologic procedures.

All patients will receive standardized general anesthesia combined with bilateral transversus abdominis plane block. The intervention group will additionally receive intrathecal morphine, whereas the control group will receive intrathecal saline. After entering the operating room, routine monitoring will include electrocardiography, pulse oximetry, noninvasive blood pressure, heart rate, and end-tidal carbon dioxide. Prior to anesthesia induction, patients in the intervention group will undergo lumbar intrathecal injection of morphine at the L3/4 or L4/5 or L5/S1 interspace. Based on previous literature and clinical experience, intrathecal morphine will be administered at a dose of 2 ug/kg. The control group will receive an equivalent volume of intrathecal normal saline under identical conditions. General anesthesia will be induced with intravenous dexmedetomidine (0.5 ug/kg), Propofol (1.5-2 mg/kg), remifentanil (TCI 4 ng/mL), and rocuronium (0.6 mg/kg), followed by endotracheal intubation. Bilateral TAPB will be performed in all patients under ultrasound guidance. A total of 60 mL of diluted bupivacaine liposome (20 mL: 266 mg diluted to 60 mL with normal saline) will be administered, with 15 mL injected at each of the bilateral subcostal and lateral approaches (total 60 mL). Anesthesia maintenance will include 1.0-1.3 MAC desflurane, remifentanil, sufentanil, rocuronium, and vasoactive medications as required. Intraoperative opioid consumption will be recorded. Postoperative analgesia will be provided using intravenous patient-controlled analgesia (PCA), consisting of 100 mg morphine diluted to a total volume of 100 mL. The PCA settings will include no background dose, a 1-mL bolus dose, and a 6-minute lockout interval. In cases of adverse events such as hypotension, fluid resuscitation and vasoactive support will be provided, and PCA parameters may be reduced or discontinued by an independent nurse if necessary. The primary outcome of this study is the Quality of Recovery-15 (QoR-15) score at 24 hours postoperatively. Secondary outcomes include postoperative pain scores, opioid consumption, postoperative nausea and vomiting, pruritus, and other opioid-related adverse events. This trial aims to evaluate whether the combination of intrathecal morphine and TAPB provides superior analgesia and improves recovery after gynecologic laparoscopic surgery.