Newswise — Botulinum toxin is of statistically significant benefit for a surprisingly common cause of crippling, often chronic, back pain, sciatica and especially buttock pain – piriformis syndrome -- according to a new clinical trial led by Loren Fishman, MD. This is the first randomized, controlled, double-blinded study confirming piriformis syndrome as a diagnosis and then verifying the beneficial results of injecting the botulinum toxin into the piriformis muscle. After much previously published peer-reviewed research, Dr. Fishman’s latest work finally solves an important, long-term medical conundrum.

Electromyography (EMG—elecrophysiological assessment of muscles and nerves) was used for both diagnosis and injection “This validates electrophysiological means to diagnose piriformis syndrome and links that technique to successful treatment,” says Dr. Fishman.The study, “Electrophysiologically identified piriformis syndrome is successfully treated with botulinum toxin A and physical therapy,” appears in the August issue of the peer-reviewed  journal Muscle and Nerve.*

Of 56 patients in the three-month study, 28 received the EMG-guided injection and 28 received placebo injection.  All had once-weekly physical therapy. The patients receiving botulinum injections reported an 81.5% improvement. They experienced an average pain reduction of from 7 on a scale of 10 down to 1.3. Controls did not significantly improve.

Dr.Fishman first used electromyography to rule out spinal causes of sciatica. He then used the FAIR test with EMG (flexion, adduction and internal rotation in stretching the piriformis muscle over the sciatic nerve), which he invented, to diagnose piriformis syndrome. The injection of botulinum toxin into the piriformis muscle also used EMG guidance. Afterward, the FAIR test with EMG was given again to measure the reduction in muscle pressure against the nerve. This test correlated closely with self-reported pain.

Many physicians have found piriformis syndrome difficult to diagnose or have been reluctant to look for it, though many peer-reviewed studies have proven it accounts for anywhere from 10% to 50% of sciatica.  In a seminal journal article, piriformis syndrome was found to be as common or more common than herniated disc.* *

In 1994, Jane Brody of the New York Times wrote, “When his (Dr. Fishman’s) work in diagnosing and treating this painful and sometimes crippling ailment was discussed in this column, it prompted more reader mail than any other single column in 17 years.”

Dr. Fishman is an assistant clinical professor at Columbia Medical School and Medical Director of Manhattan Physical Medicine and Rehabilitation.

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* Muscle & Nerve: Electrophysiologically identified piriformis syndrome is successfully treated with incobotulinum toxin and physical therapy, Loren M Fishman MD, BPhil (Oxon),  Allen Wilkins, MD, Bernard Rosner PhD. http://onlinelibrary.wiley.com/doi/10.1002/mus.25504/full

** J Neurosurg Spine 2:99–115, 2005 Sciatica of no disc origin and piriformis syndrome: diagnosis by magnetic resonance neurography and interventional magnetic resonance imaging with outcome study of resulting treatment:AARON G. FILLER, M.D., PH.D., JODEAN HAYNES, B.A., SHELDON E. JORDAN, M.D., JOSHUA PRAGER, M.D., J. PABLO VILLABLANCA, M.D., KEYVAN FARAHANI, PH.D., DUNCAN Q. MCBRIDE, M.D., JAY S. TSURUDA, M.D., BRANNON MORISOLI, B.A., ULRICH BATZDORF, M.D., AND J. PATRICK JOHNSON, M.D. Institute for Spinal Disorders, Cedars Sinai Medical Center, Los Angeles; Division of Neurosurgery, Departments of Anesthesia, Neurology and Radiology, and School of Medicine, University of California at Los Angeles; and Neurography Institute and Institute for Nerve Medicine, Santa Monica, California

Journal Link: Muscle & Nerve