Gabapentin can decrease acute pain and morphine consumption in spinal surgery patients

BACKGROUND Approximately 80% of patients who underwent spinal surgeries experience moderate to extreme postoperative pain. Gabapentin was used as an adjunct for the management of acute pain in approximately half of enhanced recovery programs. This meta-analysis aimed to illustrate the efficacy and safety of gabapentin for pain management following spinal surgery. METHODS In January 2017, a systematic computer-based search was conducted in PubMed, EMBASE, Web of Science, Cochrane Database of Systematic Reviews, and Google database. Data on patients prepared for spine surgery in studies that compared gabapentin versus placebo were retrieved. The primary endpoint was the visual analog scale (VAS) at 12 hours and 24 hours and total morphine consumption. The secondary outcomes were complications that included nausea, dizziness, somnolence, headache, pruritus, urine retention, and vomiting. After testing for publication bias and heterogeneity between studies, data were aggregated for random-effects models when necessary. RESULTS Seven clinical studies with 581 patients (gabapentin group=383, control group=198) were ultimately included in the meta-analysis. Gabapentin was associated with reduced pain scores at 12 hours and 24 hours, corresponding to a reduction of 11.18 points (95% CI, -13.85 to -8.52 points) at 12 hours and 9.94 points (95% CI, -13.99 to -5.89 points) at 24 hours on a 100-point VAS. Similarly, gabapentin was associated with a reduction in total morphine consumption (-2.04, 95% CI -2.71, -1.37). Furthermore, gabapentin can reduce the occurrence of vomiting (risk ratio [RR] 0.46, 95% CI 0.27, 0.78, P = 0.004), urine retention (RR = 0.57, 95% CI 0.34, 0.98, P = 0.041, NNT = 11.9) and pruritus (RR = 0.38, 95% CI 0.22, 0.66, P = 0.001, NNT = 5.6) and the number needed to treat (NNT = 20.1). There were no significant differences in the occurrence of nausea, dizziness, somnolence, or headache. CONCLUSIONS Gabapentin was efficacious in the reduction of postoperative pain, total morphine consumption, and morphine-related complications following spine surgery. In addition, a high dose (≥900 mg/d) of gabapentin is more effective than a low dose (<900 mg/d). The number of included studies is limited, and more studies are needed to verify the effects of gabapentin in spinal surgery patients.