Evaluation of Post-operative Analgesia with Intrathecal Morphine after Laparoscopic or Robotic Nephrectomy: A Randomised Controlled Trial

Background and Aims: Post-operative pain management in minimally invasive nephrectomy remains a critical aspect of patient care. This study explores the potential of low-dose intrathecal preservative-free morphine as a promising analgesic modality for enhancing post-operative pain control when minimising systemic opioid requirements and associated side effects, thereby improving patient outcomes. Methods: Patients scheduled for elective laparoscopic or robotic-assisted nephrectomy were included in this single-centre, double-blind, randomised, placebo-controlled trial. Preoperatively, patients were randomly assigned using a computer-generated block randomisation sequence to receive intrathecal morphine (ITM) 200 µg with 1 mL 0.5% bupivacaine hydrochloride in dextrose injection (Group M) or a sham procedure (Group C). All patients received standard intraoperative multimodal analgesia and post-operative patient-controlled analgesia with intravenous (IV) morphine. The primary outcome was 24-h IV morphine consumption. The secondary outcomes were intraoperative and 48-h post-operative fentanyl requirement, pain scores, pain on first ambulation and coughing, post-operative complications, post-operative length of hospital stay and patient satisfaction score. P <0.05 was considered statistically significant. Results: A total of 62 patients were recruited. The IV morphine consumption 24 h after surgery was significantly lower in Group M (16.5 ± 12.3 mg) versus Group C (27.2 ± 12.1 mg), P = 0.001. There were significant differences in static pain scores up to the first 12 h and dynamic pain on the first ambulation and coughing. Intraoperative and 48-h post-operative rescue fentanyl requirements were significantly lower in Group M, P < 0.05. Conclusion: ITM significantly reduces post-operative morphine requirement and post-operative pain scores.