The Preemptive Analgesic Effect of Intravenous Ketamine after Lumbar Spine Instrumentation

Lee, In Ho; Lee, Il Ok; Cho, Tae Hyung; Kong, Myoung Hoon; Lee, Mi Kyoung; Kim, Nan Sook; Choi, Young Seok; Lim, Sang Ho

Abstract

BACKGROUND: Well-localized and noxious stimuli are found to produce long-lasting neuronal sensitization. Ketamine is a NMDA receptor antagonist and exerts antinociceptive effects in many pain tests. The aim of this study was to investigate the pre-emptive and analgesic sparing effect of intravenous ketamine in adults aged 30-53 after lumbar spinal instrumentation surgery.
METHODS
We compared the effects of preoperative and postoperative intravenous ketamine 0.5 mg/kg on pain after lumbar spinal instrumentation in a double-blind, randomized study in 30 adult patients. After the induction of anesthesia, patients were allocated randomly to receive ketamine intravenously either before (n = 15) or immediately after (n = 15) surgery. Patients were instructed to ask for analgesics whenever they required pain relief and all demands were recorded. Intravenous patient-controlled analgesia (PCA) using butorphanol 16 mg and ketorolac 150 mg was introduced after recovery from general anesthesia. Visual analogue scale (VAS) pain scores were recorded at 1, 2, 3, 4, 5, 6, 9, 12, 24, 36 and 48 hours postoperatively and the total infusion dose of PCA drugs were assessed at 24 hours postoperatively.
RESULTS
VAS scores in the preoperative group were significantly lower than in the postoperative group during the first 9 hours after cessation of the operation. The total infusion dose of PCA drugs was significantly lower in the preoperative group (butorphanol 9.1 +/- 0.3 mg, ketorolac 85.3 +/- 2.5 mg) than postoperative group (butorphanol 10.7 +/- 0.2 mg, ketorolac 100.3 +/- 2 mg) (P < 0.05). No serious adverse reactions occurred.
CONCLUSIONS
Preoperative intravenous ketamine 0.5 mg/kg in lumbar spinal instrumentation is more effective in reducing postoperative analgesic requirements than it is when given after the operation.