Effect of Gabapentin on Post-Operative Pain in Sacrocolpopexy - Randomized Trial

Objectives: Enhanced recovery after surgery (ERAS) has been synonymous with increasing non-opioid multimodal therapies and decreasing opioids for post operative care . Limited data is known about the role of post-operative gabapentin among urogynecology surgical patients. The primary aim of this study is to examine the efficacy of gabapentin in decreasing postoperative pain scores in the immediate 2 weeks following minimally invasive sacrocolpopexy (MISC) surgery. Secondary aims include measuring post-operative opioid consumption, patient degree of bother, and incidence of side effects.

Methods: This was a single-site randomized control study of English-speaking adult women undergoing MISC for pelvic organ prolapse. Exclusions include concurrent sphincter or fistula repair, urethral diverticulectomy or mesh excision, current gabapentin or pregabalin use, oxygen dependency, cognitive impairment by Mini Cog score < 3, and glomerular filtration rate of < 30mL/min. Groups were randomized to standard ERAS protocol post-operative care with placebo versus study group of scheduled postoperative gabapentin plus ERAS protocol for the first two weeks following surgery. The primary outcome is the change in pain during normal activity and at rest by the validated surgical pain scale (SPS) on 2-week post-operative visit from baseline scores. Secondary outcome measures included average morphine milliequivalent (MME), validated surveys including pelvic floor distress inventory (PFDI-20) and pelvic floor impact questionnaire (PFIQ-7), and side effect incidence. Baseline and demographics data were analyzed using Student’s t-test for continuous variables and Fisher’s exact or χ2 tests for categorical variables. Our outcomes were evaluated with Student’s t-test, Wilcoxon rank sum, and χ2 tests when appropriate.

Results: Over 100 patients were screened and 32 participants (16 placebo group, 16 gabapentin group) were enrolled. Demographics including age, parity, Charlson Comorbidity Index, prior abdominal surgeries, prolapse stage, and baseline rate of bother by validated PFDI-20 and PFIQ-7 surveys did not differ by treatment group. The median change in SPS score from pre-operative baseline scores and 2-week post-operative scores in the placebo and gabapentin treatment groups at rest were 0 (-0.5, -1.0) vs 0 (-1.0, 1.0), p = 0.88, respectively; during normal activity was 0 (-1.5, 1.0) vs 0 (-1.0, 0.5), p = 0.60 respectively; and worst pain 0 (-3.0, 2.5) vs 0 (-1.5, 1.0), p = 0.94 respectively. Incidentally, there was a higher incidence for nausea, vomiting, and diarrhea side effects in the placebo group (20%) vs gabapentin group (0%), p=0.07. Median MME usage per day was 4.3 vs 1.7 in placebo vs gabapentin treatment group respectively, p = 0.14. Validated questionnaires showed overall statistically significant improvement in pelvic floor symptoms in both groups.

Conclusions: When adding scheduled post-operative gabapentin in MISC surgery two-week pain scores did not change significantly when compared to placebo.