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This Article Figures Only Full Text Full Text (PDF) CME: Take the course for this article: Volume 67, Number 2, July 25, 2006 Data Supplement Correspondence: Submit a response Correspondence: View responses Alert me when this article is cited Alert me when Correspondence are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Qerama, E. Articles by Jensen, T. S. Search for Related Content PubMed PubMed Citation Articles by Qerama, E. Articles by Jensen, T. S. Related Collections Botulinum toxin All Clinical trials All Pain Clinical trials Observational study (Cohort, Case control)

A double-blind, controlled study of botulinum toxin A in chronic myofascial pain

From the Danish Pain Research Center (E.Q., H.K., F.W.B., T.S.J.), Department of Neurophysiology (E.Q., A.F.-F.), and Department of Neurology (H.K., F.W.B., T.S.J.), Aarhus University Hospital, Denmark.

Address correspondence and reprint requests to Dr. Erisela Qerama, Department of Neurophysiology, Building 10, Parterre, Noerrebrogade 44, DK-8000 Aarhus, Denmark; e-mail: erisela{at}akhphd.au.dk

Background: Recent studies have reported a potential analgesic effect of botulinum toxin A (BTXA) in musculoskeletal pain. The present double-blind, randomized, placebo-controlled, parallel clinical trial studied the effect of BTXA on pain from muscle trigger points and on EMG activity at rest and during voluntary contraction.

Methods: Thirty patients with trigger points in the infraspinatus muscles received either 50 units/0.25 mL of BTXA or 0.25 mL of isotonic saline. Baseline measures were determined during a run-in period of 1 week. Outcome measures including local and referred spontaneous pain, pain detection and tolerance thresholds to mechanical pressure, and shoulder movement were assessed at 3 and 28 days after injection. The interference pattern of the EMG during maximal voluntary effort of infraspinatus muscle was recorded and a standardized search for spontaneous electrical motor endplate activity at the trigger points was performed before and 28 days after BTXA or saline injection.

Results: BTXA reduced motor endplate activity and the interference pattern of EMG significantly but had no effect on either pain (spontaneous or referred) or pain thresholds compared with isotonic saline.

Conclusions: The results do not support a specific antinociceptive and analgesic effect of botulinum toxin A.

Additional material related to this article can be found on the Neurology Web site. Go to www.neurology.org and scroll down the Table of Contents for the July 25 issue to find the title link for this article.

Disclosure: The authors report no conflicts of interest.

Received June 20, 2005. Accepted in final form March 30, 2006.

This article has been cited by other articles:

				B. A. Richards, E . Qerama, A . Fuglsang-Frederiksen, H . Kasch, F .W. Bach, and T .S. Jensen A double-blind, controlled study of botulinum toxin A in chronic myofascial pain Neurology, March 20, 2007; 68(12): 963 - 964. [Full Text] [PDF]

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