Persistent pain after lumbar surgery (failed back surgery syndrome [FBSS]) remains a leading indication for chronic analgesia. However, no analgesics have proven efficacious for this condition. Although trials have evaluated gabapentinoids for chronic low back pain, none of these trials focused solely on FBSS. This randomized, double-blind cross-over trial evaluated the efficacy of gabapentin (1800 mg/day) for FBSS. Eligible patients had a diagnosis of FBBS, an average daily pain score of at least 4 of 10, a neuropathic pain component (indicated by the PainDetect), and reported at least half of their pain radiating in their lower extremity. Participants were randomized to 2, 7-week study periods separated by a 10-day washout. The primary outcome measure was a 0 to 10 numeric rating scale (NRS) of average pain. Secondary measures included the McGill Pain Questionnaire and Patient Global Impression of Change. The treatment effect was analyzed using a mixed effect analysis of covariance with fixed effects for treatment, period, and baseline 7-day mean NRS pain score and a random effect for the participant. The outcome of the model was the mean 7-day NRS score for the last 7 days of each treatment period. Thirty-two participants were randomized and included in the primary analysis; 25 completed both study periods. No difference was detected between treatments on any outcome measure, including the primary (least square mean difference in NRS: −0.01 confidence interval: [−0.22 to 0.20]). Given the escalating rate of complex lumbar surgery, future research to develop novel therapies for this prevalent syndrome is needed.
No effect of extended-release gabapentin for failed back surgery syndrome was detected in this single-site 2-period, double-blinded, cross-over trial.
aDepartment of Anesthesiology and Perioperative Medicine, University of Rochester, Rochester, NY, United States
bTranslational Pain Research, Department of Neurosurgery, University of Rochester, Rochester, NY, United States
Departments of cBiostatistics and Computational Biology and
dNeurosurgery, University of Rochester, Rochester, NY, United States
Corresponding author. Address: Department of Anesthesiology and Perioperative Medicine, University of Rochester, 601 Elmwood Ave, Box 604, Rochester, NY 14642. Tel.: +1 585 276 5661; fax: +1 585 244 7271. E-mail address: email@example.com (J.S. Gewandter).
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Received September 25, 2018
Received in revised form December 10, 2018
Accepted December 19, 2018