Study Design: Retrospective cohort study Objectives: To investigate the effect of perioperative gabapentin administration on postoperative pain and opioid use in elderly patients after elective posterior lumbar fusion. Methods: This was a single-center study of patients over the age of 65 who underwent elective posterior lumbar fusion. The cohort was stratified into two groups based on perioperative gabapentin administration defined as use both in the immediate preoperative period and postoperatively during hospitalization. Mean daily visual analogue scale (VAS) pain scores and mean daily morphine equivalent dosage (MED) during the postoperative hospital stay were compared between these groups using traditional regression and inverse probability weighting. Results: There were 350 patients who received gabapentin perioperatively and 78 patients who did not receive gabapentin. Multivariate regression did not demonstrate a difference in daily MED (beta = -6.6 mg, p = 0.816) or daily pain scores (beta = 0.04, p = 0.257) averaged over the first seven postoperative days. Sub-analysis stratifying by each individual postoperative day also did not demonstrate a difference in MED or pain scores. Conclusion: This study did not find perioperative gabapentin administration to be beneficial in reducing postoperative VAS pain scores or opioid use in the acute postoperative period for elderly patients undergoing posterior lumbar fusion. These findings are consistent with recent literature suggesting gabapentin is of minimal benefit in postoperative multimodal analgesia regimens.

The authors have declared no competing interest.

This study did not receive any funding

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

IRB of the University of Iowa waived ethical approval for this work.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.

Yes

All data produced in the present study are available upon reasonable request to the authors