Comparison of intravenous patient-controlled analgesia with buprenorphine versus morphine after lumbar spinal fusion--a prospective randomized clinical trial.

BACKGROUND: Opioid-based patient-controlled analgesia (PCA) has been used widely and effectively after spine surgery. The untoward effects of intravenous opioids could vary with the drug and dose applied. Buprenorphine, a partial opioid agonist, might be devoid of the adverse effects which the traditional opioids have. We conducted this prospective randomized clinical trial to evaluate the efficacy and safety of buprenorphine for intravenous PCA after spine surgery.

METHODS: Fifty patients undergoing elective lumbar spinal fusion were randomly assigned to either buprenorphine or morphine group. PCA was administered in a double-blind manner for a 2-day postoperative course. The evaluation was initiated after patients were transferred to the post-anesthetic care unit. Pain assessment with visual analog scale (VAS) at rest and after pain elicitation by sitting was carried out and recorded at 6, 24, 48 hrs after surgery. Untoward effects were also collected.

RESULTS: Twenty-five patients were randomized to each group. One patient in the buprenorphine group dropped out from the study due to dizziness. There was no difference between the groups with respect to the baseline variables. The VAS scores at rest and after elicitation of pain by sitting showed no difference between both groups. The delivered volume of buprenorphine, the numbers of demand and delivery, and the demand/delivery ratio were higher in buprenorphine than morphine group at 6 hr after surgery but were not different later. No major complications occurred in both groups. The pruritus incidence in buprenorphine group was significantly lower than in morphine group (0 vs. 24%, P = 0.02). Other adverse effects were similar in both groups.

CONCLUSIONS: Both buprenorphine and morphine by intravenous PCA provided adequate pain relief after posterior lumbar spinal fusion. The incidences of side effects were similar in both groups except for pruritus which did not appear in buprenorphine group. Buprenorphine was as efficient as morphine and safe for intravenous PCA after spine surgery.