The use of intrathecal morphine in non-abdominal surgery: a scoping review.

Background: Intrathecal morphine can reduce pain and opioid requirements needed for postoperative pain relief. It can potentially aid in the effectiveness of enhanced recovery protocols in non-abdominal surgery. However, concerns about side-effects may have hindered its use. This scoping review evaluates the effectiveness, appropriate dosage, and adverse effects of intrathecal morphine in non-abdominal surgery. Methods: We systematically searched for randomised controlled trials examining the use of intrathecal morphine in non-abdominal surgery. Results: The search identified 75 trials involving 4685 patients. We undertook a scoping review of these randomised controlled trials, including bias assessments, to comprehensively analyse the effectiveness and side-effects of intrathecal morphine. The findings indicate that intrathecal morphine reduced postoperative pain and opioid consumption after spinal surgery, thoracic surgery, and orthopaedic lower extremity surgery. However, it was associated with an increased incidence of itching, postoperative nausea and vomiting, and urinary retention, particularly in orthopaedic procedures. Delayed respiratory depression was absent with low to moderate doses (<500 μg) in the reviewed studies. Conclusions: This review supports the effectiveness of intrathecal morphine in non-abdominal surgery. However, the benefits must be carefully weighed against potential side-effects that could lead to prolonged hospital stays. Clinical trial registration: PROSPERO-registry CRD42021233936.