The aim of this study was to compare topical 5% lidocaine patch with placebo patch in the treatment of myofascial pain syndrome of the upper trapezius.
In this prospective, randomized, double-blind, placebo-controlled study, 60 participants were randomly assigned, placing 31 subjects in the 5% lidocaine patch group and 29 subjects in the placebo patch group. We used the Verbal Rating Scale (VRS), the Pressure Pain Threshold, the ranges of motion of the neck, and the Neck Disability Index to evaluate the subjective pain intensity, objective pain intensity, ranges of motion, and disability of the neck, respectively. Outcome measures were performed before (day 0) the treatment course, 12 hrs after removal of the final patch on the seventh day (day 7), and 1 wk (day 14) and 3 wks (day 28) after the completion of treatment course.
The characteristics of the participants did not differ at baseline. Pain intensity assessed by the VRS decreased at day 7 in both the lidocaine patch and placebo patch groups. There was no significant difference between the two groups in the VRS, the Pressure Pain Threshold, the ranges of motion, and the Neck Disability Index. At day 14, the experimental group continued to improve in the VRS (1.06), but the pain of the placebo group aggravated (VRS, 1.5). The difference is significant (P = 0.03). In addition, the Neck Disability Index in the lidocaine patch group decreased significantly as compared to that in the placebo group. The pain-relieving effect of the lidocaine patch attenuated, and it was not significantly different between the two groups at day 28 in the VRS and the Neck Disability Index. Neither the Pressure Pain Threshold nor the ranges of motion were significantly different through the periods of this study.
The application of the 5% lidocaine patch is probably superior to the placebo patch in relieving pain and in reducing associated neck disability for a period of longer than 1 wk for treating patients with myofascial pain syndrome of the upper trapezius.
From the Department of Physical Medicine and Rehabilitation, College of Medicine, National Cheng Kung University Hospital (Y-CL, T-SK, P-CH, W-JY, W-CC, S-MC); and Medical Device Innovation Center (Y-CL, T-SK, S-MC), National Cheng Kung University, Tainan, Taiwan.
All correspondence and requests for reprints should be addressed to: Shu-Min Chen, MD, Department of Physical Medicine and Rehabilitation, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan 704, Taiwan. the use in myofascial pain syndrome. Supported by National Cheng Kung University Hospital (NCKUH), College of Medicine, National Cheng Kung University, Tainan, Taiwan (grant for the project and the 5% lidocaine patch).
CME Objectives: Upon completion of this article, the reader should be able to (1) understand the prevalence and pathophysiology of myofascial pain syndrome; (2) understand the potential benefits of the lidocaine patch in the treatment of myofascial pain; and (3) describe the mechanism of action and potential side effects of using a lidocaine patch in the treatment of myofascial pain
Accreditation: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The Association of Academic Physiatrists designates this activity for a maximum of 1.5 AMA PRA Category 1 Credit(s). Physicians should only claim credit commensurate with the extent of their participation in the activity.
Disclosures: Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article.