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Large-Array Surface Electromyography in Low Back Pain: A Pilot Study

Finneran, Mark T., MD*; Mazanec, Daniel, MD; Marsolais, Marian E., MS; Marsolais, Ernest B., MD, PhD§; Pease, William S., MD

doi: 10.1097/01.BRS.0000067565.16832.B9

Study Design. A large-array surface electromyography device was used to collect data from healthy pain-free persons and from those with acute or chronic low back pain. Images of regional muscle electromyographic activity were assessed visually, and maximum root mean square values were compared statistically.

Objective. To determine whether data differs by patient type.

Summary of Background Data. Whereas there is a good understanding of the anatomy and psychosocial aspects of low back pain, there is a need to understand better the physiology of low back pain.

Methods. Large-array surface electromyography data were collected from the low back muscles of 201 participants over a 3-month period using a 63-electrode fixed array and a standardized protocol. Color images representing the voltage root mean square difference of each electrode pair were created. Three images from each of three positions (standing upright, standing in 20° of trunk flexion, standing holding weights) were collected from each participant. Serial studies were performed on the acute population over a 6-week follow-up period.

Results. Images of regional muscle activity from 92.7% of normal controls (n = 163) showed symmetrical activity. Patients with acute (n = 13) or chronic (n = 25) low back pain had multifocal and/or asymmetrical patterns. Symmetrical patterns returned in the three patients whose acute pain resolved during the study. Maximum root mean square values were higher among patients with acute (P = 0.03) and chronic (P = 0.04) pain than among control subjects.

Conclusions. Large-array surface electromyography produced data from patients with back pain that differed from data on subjects without back pain. This method may be useful in evaluating patients with low back pain.

From *Ashland Industrial Medicine Services, the

†Cleveland Clinic Foundation Center for the Spine,

‡Statistical Consultant,

§Orthopedic Surgery and Biomedical Engineering, Case Western Reserve University, and

∥Physical Medicine and Rehabilitation, The Ohio State University College of Medicine and Public Health.

Supported by a grant from the Paraspinal Diagnostic Corporation.

Acknowledgment date: March 26, 2002.

First revision date: August 26, 2002.

Second revision date: December 2, 2002.

Acceptance date: December 9, 2002.

The device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication. Corporate/Industry funds were received to support this work. Although one or more of the author(s) or family members has/have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this manuscript, benefits will be directed solely to a research fund, foundation, educational institution, or other nonprofit organization which the author(s) has/have been associated.

Address correspondence and reprint requests to Mark T. Finneran, MD, 886 Woodmere, Wooster, OH 44691; E-mail:

© 2003 Lippincott Williams & Wilkins, Inc.