Preoperative multimodal administration of morphine in arthroscopic surgery

Abstract

INTRODUCTION The aim of the study was to demonstrate the possible effects of preoperative intra-articular, intravenous, or intrathecal administration of morphine on postoperative pain management. Sixty patients undergoing arthroscopic menisectomy were included. Spinal anesthesia was performed in the lateral decubitus position with 3 ml of 0.5% hyperbaric bupivacaine, and the patients were randomized into 4 groups. The IVM (intravenous, i.v., morphine) group received 3 mg of i.v. morphine after completion of spinal anesthesia, the ITM (intrathecal morphine) group received 0.3 mg of morphine together with bupivacaine during spinal anesthesia, the IAM (intra-articular morphine) group received 3 mg intra-articular morphine diluted in 10 ml of saline after spinal anesthesia had been induced but 15 min before surgery, while the C (control) group did not receive any drugs in addition to spinal anesthesia. The sensory block level was determined 15 min after spinal anesthesia. Pain at rest (by visual analogue scale, VAS) and pain at 30 degrees of flexion (by verbal rating scale, VRS) were evaluated during each of the first 2 h of the postoperative period and once every 4 h thereafter until 24 h. In each group; the number of patients in need of analgesics, the timing of the first analgesic intake (duration of analgesia), and the cumulative dose of analgesics were recorded. The mean duration of analgesia in the IAM group was significantly longer and the mean analgesic intake was significantly lower when compared with the other groups (p < 0.05). The mean VAS value of the ITM group at the 4th postoperative hour was significantly lower than that of the other groups. Mean VAS values at 8 and 12 h and mean VRS values at 4 and 8 h were significantly lower in the ITM and IAM groups (p < 0.05). The ITM group had the highest rates of nausea, vomiting, pruritus, and headache (p < 0.05). It was concluded that the preoperative administration of morphine, either intrathecally or intra-articularly, provides postoperative pain relief. Of these two, the intra-articular route seems to be superior in terms of fewer side-effects (nausea, vomiting, and pruritus), longer duration of analgesia, and reduction of total need for analgesics.