Botulinum toxin injection for myofascial pain syndrome

Journal/Book: Rehab in Review Vol. 6 Nr.10 1998 / Phys Rehab Kur Med 9 (1999) S. M30. 1998 / 1999;

Abstract: Wheeler A et al.: A Randomized Double-blind Prospective Pilot Study of Botulinum Toxin Injection for Refractory Unilateral Cervico-thoracic Paraspinal Myofascial Pain Syndrome. Spine 23 (15) (1998 August 1) 1662 - 1667 Trigger point injections have long been used as a component of treatment for localized myofascial pain syndrome (MPS). However controversy remains concerning whether a therapeutic substance is needed or whether improvement may result from dry needling alone. This study sought to determine the therapeutic efficacy of botulinum toxin type A (BTXA) acetylcholine blockers for treatment of paravertebral trigger points. This randomized double-blind prospective study included 33 subjects with chronic unilateral neck pain. All had trigger points of at least three months duration and had failed conservative therapy. Subjects were divided into three groups to receive a trigger point injection of either 50 units of BTXA in 2 cc of normal saline 100 units of BTXA in 2 cc of normal saline or 2 cc normal saline alone. Subjects were then assessed with the Neck Pain and Disability (NPAD) Visual Analog Scale before and after injections were administered. All were re-evaluated with the same scales and with repeated algometry at weeks one three six and nine and months three and four. Thirteen of the patients (36%) underwent a second injection consisting of 100 units of BTXA. Each of the three groups demonstrated significant improvement in algometry scores (p = 0.0001) and in the NPAD scores (p = 0.0001). The greatest improvement was noted in measurements taken at one week post-injection. No significant differences were found among groups based on injection material. For those subjects who had received a second injection however 80% of those first receiving 50 units of BTXA and 75% of those initially receiving 100 units of BTXA enjoyed clinical improvement. However this finding was not statistically significant. Conclusion: This study using injections of BTXA into myofascial trigger points fails to reveal a superior benefit of BTXA over placebo saline. However the authors suggest that additional BTXA injections may result in improved outcome. ___MH

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