Sustained postoperative gabapentinoids do not result in clinically important decreases in postoperative delirium, pain, or opioid dose in gabapentin naïve lumbar fusion patients

Background By decreasing postoperative pain and opioids, sustained postoperative gabapentinoids might decrease delirium after spine surgery. Prior randomized trials of sustained postoperative gabapentinoids after spine surgery have either not assessed delirium or excluded preoperatively opioid tolerant patients. The aim of this study was to determine in older lumbar fusion patients who were not prescribed preoperative gabapentinoids if sustained postoperative gabapentinoids affected postoperative delirium, pain, and opioid dose. Methods An electronic medical record search of an academic medical center identified 303 posterior lumbar fusion patients (age ≥ 65 years) not prescribed preoperative gabapentinoids who received gabapentinoids starting on postoperative day 1 (n=184) or did not (n=119) Propensity score-weighted models and Bayesian analysis determined the effects of postoperative gabapentinoids on postoperative delirium, pain, and opioid dose. Results The median postoperative gabapentin dose equivalent was 900 mg/day. The delirium hazard ratio (HR) was not significantly greater in the gabapentin group: 1.40 (95% credible interval [CrI] 0.66 to 2.23), but with only a 4% probability that gabapentin decreased delirium (HR ≤ 0.8) vs. a 65% probably that gabapentin increased delirium (HR ≥ 1.2). The daily average pain score was not significantly less in the gabapentin group: -0.11 points out of 10 (95% CrI -0.41 to 0.18), with a 0% probability that the minimum clinically important difference (MCID) of -1 point was attained. The daily opioid dose was statistically significantly less in the gabapentin group: -10.2 mg/day (95% CrI -18.8 to -2.1), but with a 0% probability that the MCID of -30 mg/day was attained. Conclusions In older lumbar fusion surgery patients who were not prescribed preoperative gabapentinoids, sustained postoperative gabapentinoids did not significantly affect delirium incidence and did not result in clinically important decreases in pain or opioid dose. Our results suggest gabapentinoids may be more likely to increase delirium than to decrease it.