Efficacy and Safety of Intrathecal Morphine in Foot and Ankle Surgery Patients; A Retrospective Study

Abstract

Intrathecal morphine is an effective technique for pain control, easy to perform and simply available in all clinical settings. Studies have reported that 0.1 mg of intrathecal morphine was effective and safe in hip surgery and cesarean section. However, the efficacy of intrathecal morphine for foot and ankle surgery (FAAS) was still unknown. We aimed to evaluate the efficacy of 0.1 mg intrathecal morphine for postoperative pain control within the first 24 hours after FAAS. Data was collected from 136 patients. The numerical rating scales (NRS) taken within the first 24 hours post-operation, written in patients’ medical records, were assessed. Records of time to first rescue analgesic, total rescue analgesic consumption, supplemental or multimodal analgesics, as well as incidence of nausea and vomiting, pruritus, urinary retention, and respiratory depression requiring treatment were also reviewed. The average NRS were less than 3 at 0, 6, 12, and 24 hours after intrathecal morphine administration. The number of patients who needed rescue analgesics in the first 24 hours was 25 (18.4%). Thirty-three patients (24.26 %) had nausea and vomiting, 9 patients (6.62%) had pruritus, and 16 patients (11.8 %) had urinary retention. None of the patients had respiratory depression. Therefore, it was concluded that 0.1 mg of intrathecal morphine is effective for controlling postoperative pain in FAAS, though appropriate dosage should be further studied; there are still some dose-dependent complications to be considered.