Gabapentin can decrease acute pain and morphine consumption in spinal surgery patients: A meta-analysis of randomized controlled trials

Abstract

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.

Figure 1

Flowchart of study search and inclusion criteria.

Figure 2

(A) The risk of bias graph. (B) Risk of bias of included randomized controlled trials. +, no bias; –, bias; ?, bias unknown.

Figure 3

(A) Forest plots of the included studies comparing the VAS at 12 h. B, Forest plots of the included studies comparing the VAS at 24 h. VAS = visual analog scale.

Figure 4

(A) Funnel plot of VAS at 12 h. (B) Begg's test of VAS at 12 h. VAS = visual analog scale.

Figure 5

(A) Funnel plot of VAS at 24 h. (B) Begg's test of VAS at 24 h. VAS = visual analog scale.

Figure 6

(A) Sensitivity analysis of the VAS at 12 h. (B) Sensitivity analysis of the VAS at 24 h. VAS = visual analog scale.

Figure 7

(A) Scatter plot showing the relationship between the dose of gabapentin and the VAS at 12 h. (B) Scatter plot showing the relationship between the dose of gabapentin and the VAS at 24 h. VAS = visual analog scale.

Figure 8

Forest plots of the included studies comparing the total morphine consumption.

Figure 9

Forest plots of the included studies comparing the occurrence of (A) nausea, (B) dizziness, (C) somnolence, (D) headache.

Figure 10

Forest plots of the included studies comparing the occurrence of (A) pruritus, (B) urine retention, (C) vomiting.