ANALGESIC EFFICACY OF INTRATHECAL DIAMORPHINE FOR POSTOPERATIVE PAIN RELIEF AFTER MAJOR LUMBAR SPINE SURGERY

Background: Effective pain management is an important component of postsurgical care. Lumbar spine reconstructive surgery is associated with severe postoperative pain and it requires multimodal pain management. This prospective, randomized study compared the analgesic efficacy of single injection of three different does of intrathecal diamorphine with placebo. Methods: 120 patients ASA I-III undergoing major lumbar spine surgery were enrolled in this prospective and randomized study. Thirty patients were included in each group. Group A: patients received intrathecal diamorphine 5 ug/kg. Group B: patients received intrathecal diamorphine 10 ug/kg. Group C: patients received intrathecal diamorphine 15 ug/kg. Group D: (control) patients received intrathecal normal saline 0.9% injection and were connected to a PCA pump (patient controlled intravenous analgesia) on arrival in the postanesthesia care unit (PACU). For 48 h after surgery the following observations were recorded: pain on a numerical scale at rest; pain on a numerical scale on movement (visual analogue scale ,VAS) time to first request and quantity of morphine used , cumulative morphine consumption included IV morphine administered in the PACU and total dose of morphine PCA used. Results: There was significant difference between the four groups in severity of the pain immediately after surgery. In post anesthesia care unit (PACU), all patients in diamorphine groups were extremely pain free with zero pain score and required no supplementary analgesia . Patients in group D (control) had the highest pain score with high morphine consumption for 48 hours. The quality of analgesia (VAS) and patient’s satisfaction were statistically significant in diamorphine groups compared with group D (control). Patients in groups(C D) had the highest number of patients suffered from nausea/vomiting and pruritus. Conclusions: Single intrathecal injection of diamorphine (10 ug/kg) is very effective in reducing morphine consumption after major lumbar spine surgery with high patient’s satisfaction.