Tag Archive | sciatica

In Chronic Sciatica, Gabapentin Quells Nerve Pain Better than Pregabalin

This post comes from Fred Nelson, MD, an orthopaedic surgeon in the Department of Orthopedics at Henry Ford Hospital and a clinical associate professor at Wayne State Medical School. Some of Dr. Nelson’s tips go out weekly to more than 3,000 members of the Orthopaedic Research Society (ORS), and all are distributed to more than 30 orthopaedic residency programs. Those not sent to the ORS are periodically reposted in OrthoBuzz with the permission of Dr. Nelson. 

Orthopaedic surgeons may not be at the forefront of dealing with nonoperative nerve pain, but many of our patients who are not candidates for surgery suffer from spine-related nerve pain in their limbs, such as sciatica. Both gabapentin (GBP, Neurontin) and pregabalin (PGB, Lyrica) are used to treat chronic sciatica (CS).

Gamma-aminobutyric acid (GABA) is an important pain-related neurotransmitter, although neither GBP nor PGB affect the GABA receptor. Instead, both drugs associate with the ligand of the auxiliary α2δ-1 and α2δ-2 subunits of certain voltage-dependent calcium channels in nerves. Among other uses, Neurontin is prescribed to treat diabetic peripheral neuropathy, and Lyrica is commonly used to treat fibromyalgia.

Investigators reporting in JAMA Neurology sought to help guide practitioners in the initial choice of drug. Eighteen patients with MRIs corroborating single-sided nerve-root sciatic pain of at least 3 months duration were evaluated in an interim analysis as part of a randomized, double-blind, double-dummy crossover trial of PGB vs GBP (8 weeks of exposure to each drug with a 1-week washout in between). The primary outcome was pain intensity measured with a 10-point visual analog scale (VAS) at baseline and 8 weeks. Secondary outcomes included disability as measured with the Oswestry Disability Index and the severity and frequency of adverse events.

Relative to baseline, both drugs showed significant VAS pain reductions and disability-score improvements, However, head-to-head, GBP showed superior VAS pain reduction (mean [SD], GBP: 1.72 [1.17] vs PGB: 0.94 [1.09]; P = 0.035), regardless of the order in which it was given. There were no between-drug differences in disability scores, but adverse events for PGB were more frequent (PGB, 31 [81%] vs GBP, 7 [19%]; P = 0.002), especially when PGB was taken first.

The authors conclude that GBP was superior with fewer and less severe adverse events, and they suggest that gabapentin should be commenced before PGB to permit optimal crossover of medicines.

Reference
Robertson K, Marshman LAG, Plummer D, Downs E. Effect of Gabapentin vs Pregabalin on Pain Intensity in Adults WIth Chronic Sciatica: A Randomized Clinical Trial. JAMA Neurol. 2018 Oct 15. doi: 10.1001/jamaneurol.2018.3077. [Epub ahead of print] PMID: 30326006

JBJS Case Connections—Peculiar Sciatic Nerve Problems

F1.medium.gifMost insults to the sciatic nerve arise from intervertebral disc conditions or spinal stenosis. However, beyond these common etiologies for sciatic-nerve problems are a host of other, rarer causes. This month’s “Case Connections” explores 4 such peculiar examples.

The springboard case report, from the October 12, 2016 edition of JBJS Case Connector, describes 3 instances of sciatica caused by nerve compression from a perineural cyst arising from a paralabral cyst. All 3 patients were successfully treated with arthroscopic decompression. Three additional JBJS Case Connector case reports summarized in the article focus on:

  • A 70-year-old woman with a history of thromboembolism who experienced sciatic nerve palsy from an anticoagulant-induced hematoma
  • A 31-year-old woman with sciatic endometriosis who was successfully treated by a team of gynecologists, orthopaedists, and microsurgeons
  • A 66-year-old woman in whom sciatic nerve injury occurred after repeated attempts at closed reduction of a dislocated hip prosthesis

Orthopaedists evaluating patients with symptoms characteristic of sciatic-nerve pathology should recognize that these symptoms may arise from a variety of etiological pathways. These patients require a complete history-taking, a thorough physical exam, and an attempt to rule out all possible lumbar causes.