Electrophysiologically identified piriformis syndrome is successfully treated with incobotulinum toxin a and physical therapy

Muscle Nerve. 2017 Aug;56(2):258-263. doi: 10.1002/mus.25504. Epub 2017 Apr 2.

Abstract

Introduction: Piriformis syndrome is entrapment of the sciatic nerve by the piriformis muscle.

Methods: In this article we describe a 56-person randomized, double-blind, controlled study involving physical therapy and incobotulinum toxin A or placebo. Inclusion criteria were 3-SD delay of posterior tibial (PT) or fibular (FN) H-reflexes on flexion, adduction, and internal rotation (FAIR) testing, and normal paraspinal electromyographic findings. Outcome measures included adverse side effects, visual analog scale (VAS) findings, and H-reflex delay on the FAIR test.

Results: Mean intervention VAS score decreased significantly more compared with placebo at 2, 4, 6, 8, 10, and 12 weeks post-injection (P < 0.0001). FAIR test scores for PT, but not FN, decreased significantly more compared with placebo at 2, 4, 6, and 8 weeks post-injection (PT: P = 0.038, 0.003, 0.003, and 0.046). Adverse effects were minimal. VAS slope and PT FAIR test results varied significantly (P < 0.0001).

Conclusion: Incobotulinum toxin A chemodenervation may be useful for treating piriformis syndrome as identified by the FAIR test. Muscle Nerve 56: 258-263, 2017.

Keywords: FAIR test; botulinum; clinical trial; electrodiagnosis; physical therapy; piriformis; sciatica.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Botulinum Toxins, Type A / therapeutic use*
  • Electrodiagnosis
  • Female
  • Follow-Up Studies
  • H-Reflex / physiology
  • Humans
  • Male
  • Neuromuscular Agents / therapeutic use*
  • Physical Therapy Modalities*
  • Piriformis Muscle Syndrome* / drug therapy
  • Piriformis Muscle Syndrome* / physiopathology
  • Piriformis Muscle Syndrome* / rehabilitation
  • Retrospective Studies
  • Severity of Illness Index
  • Treatment Outcome
  • Visual Analog Scale

Substances

  • Neuromuscular Agents
  • Botulinum Toxins, Type A
  • incobotulinumtoxinA