High-Volume Infiltration Analgesia in Major Lumbar Spine Surgery. A Randomized, Placebo-Controlled, Double-Blind Trial

Abstract

Background: High-volume local infiltration analgesia is effective in knee arthroplasty, but the analgesic efficacy of systematic infiltration with high-volume local anesthetic in major lumbar spine surgery in L3 to S1 has not been clarified. We conducted a trial to evaluate the analgesic efficacy of intraoperative Local Infiltration Analgesia (LIA) administration and postoperatively via injections through intraoperatively placed wound catheters. Methods: In a randomized, double-blind, placebo-controlled trial in 48 patients undergoing major lumbar spine fusion surgery, 70 mL saline (n=24) or ropivacaine 0.5% with adrenaline (n=24) was infiltrated using a systematic technique to all tissue incised, handled or instrumented during surgery and with repeated injections at 6, 12 and 24 h postoperatively with 10, 10 and 20 mL. Twenty-two patients in each group were used for analysis. Allocation was determined by using a computer generated random sequence concealed in consecutively numbered sealed envelopes, which were opened on the morning of surgery. For postoperative analgesia 2 multi-hole catheters were placed under the fascia of the m. erector spinae and subcutaneously in accordance with the randomization. The primary end-point was postoperative pain at rest, during leg elevation and walking for 48 hours postoperatively. Secondary end-point was the amount of administered opioid in the same period. Results: VAS pain scores were only significantly lower at 3 hours postoperatively in the ropivacaine group with straight leg elevation (p=0.0169) and at 7 hours in the ropivacaine group during walking (p=0.0133). At 25 hours postoperatively, there was a slightly significant reduction in pain scores from repeated injection of ropivacaine vs. saline in the catheters both during elevated straight leg test (p=0.0495) and during walking (p=0.0192). Rescue opioid requirements (24 h) were about 30 % lower in the ropivacaine group (p<0.05). No local anesthetic side effects were observed. Conclusion: Intraoperative high-volume wound infiltration with ropivacaine in major lumbar spine fusion surgery may only have a small analgesic effect in early postoperative pain management and after local anesthetic administration through multiholed wound catheters 24 hours postoperatively.