Intramuscular Local Anesthetic Infiltration at Closure for Postoperative Analgesia in Lumbar Spine Surgery: A Systematic Review and Meta-Analysis

Study Design. Systematic Review and Meta-Analysis Objective. To identify whether intramuscular local anesthetic infiltration prior to wound closure was effective in reducing postoperative pain and facilitating early discharge following lumbar spine surgery. Summary of Background Data. Local anesthetic infiltration prior to wound closure may form part of the multimodal strategy for postoperative analgesia, facilitating early mobilization and discharge. Although there are a number of small studies investigating its utility, a quantitative meta-analysis of the data has never been performed. Methods. This review was conducted according the PRISMA statement and was registered with the PROSPERO database. Only randomized controlled trials were eligible for inclusion. Key outcomes of interest included time to first analgesic demand, total postoperative opiate usage in the first 24 hours, visual analogue score (VAS) at 1, 12 and 24 hours and postoperative length of stay. Results. Eleven publications fulfilled the inclusion criteria. A total of 438 patients were include; 212 in the control group and 226 in the intervention group. Local anesthetic infiltration resulted in a prolonged time to first analgesic demand (mean difference (MD) 65.88 minutes, 95% confidence interval (95% CI) 23.70 to 108.06, P.0.002) as well as a significantly reduced postoperative opiate demand (M.D. −9.71 mg, 95% CI −15.07, −4.34, p = 0.0004). There was a small but statistically significant reduction in postoperative visual analogue score (VAS) at 1 hour (M.D. −0.87 95%CI −1.55, −0.20, p = 0.01), but no significant reduction at 12 or 24 hours (p = 0.93 and 0.85 respectively). Conclusion. This systematic review and meta-analysis provides evidence that postoperative intramuscular local anaesthetic infiltration reduces postoperative analgesic requirements and the time to first analgesic demands for patients undergoing lumbar spine surgery. Key research priorities include optimization of the choice and strength of local anaesthetic agent and health-economic analyses to strengthen the case for routine use of postoperative local anesthetics in lumbar spine surgery. Level of Evidence: 1