A Case-control Study of Preemptive Analgesia for Postoperative Pain in Patients Undergoing Posterior Lumbar Interbody Fusion

Abstract

A case-control clinical study of preemptive analgesia for postoperative pain was conducted.To compare the efficacy of 2 preemptive analgesics: continuous subcutaneous morphine alone (SC) and continuous subcutaneous morphine combined with single intrathecal injection of morphine (SI).Systemic opioids are known to be effective for controlling the postoperative pain. Only a few studies have investigated the efficacy of preemptive analgesia using morphine. In a previous study, continuous subcutaneous morphine brought some analgesic effects with a low rate of complications. However, the analgesic effect was not sufficient.Forty-four patients were enrolled in this study. SC and SI procedures for preemptive analgesia were conducted for the 22 patients. All the patients underwent posterior lumbar interbody fusion with instrumentation. Pain management was assessed using the Visual Analog Scale (VAS). Moreover, use of supplemental analgesics, time of first request for supplemental analgesics, and side effects were investigated.No baseline variable differences between the groups were observed. From immediately after surgery (at 0 h) to 24 hours after surgery, the VAS of the SI group was significantly lower than that of the SC group. The average VAS of the SI group was always less than 30 at any time point. No significant difference was observed in the use of supplemental analgesic drugs between the 2 groups, but the time of first request of the SC group was shorter than that of the SI group. Minor side effects were observed in 3 cases of the SC group and in 6 cases of the SI group. In 1 case of the SI group, a nasal airway was used for a few hours owing to mild respiratory depression.SI provided a favorable analgesic effect at any time point. The VAS score was always below 30. Major complications were not observed in either group, but more careful observation for respiratory status was required after the SI procedure. SI can be an attractive method for postoperative analgesia and accomplished with technical ease.