The purpose of this study was to determine the neuromuscular reflex responses of the erector spinae musculature to spinal manipulative thrusts (SMTs) in patients with LBP. 20 (10 male/10 female, mean age = 43 yrs.) consecutive LBP patients received MFMA SMTs delivered to the transverse and spinous processes of T8, T12, L2, L4, L5, and the sacral base and PSIS by means of an Activator Adjusting Instrument (AAI) equipped with an impedance head. Surface, linear enveloped, electromyographic (sEMG) recordings were obtained from electrodes located bilaterally over the L5 and L3 erector spinae muscles during each of the thrusts. Repeated pre. post isometric extension strength tests were performed to normalize reflex data. 1600 sEMG recordings were analyzed from 20 SMT treatments and comparisons were made between segmental level, segmental contact point (spinous vs. tranverse processes), and magnitude of the sEMG reflex response. SEMG threshold was further assessed for correlation of patient self. reported pain and disability, Consistent, but relatively localized sEMG reflex responses occurred in response to the MFMA SMTs. 95 % of patients showed a positive sEMG response to MFMA SMT, Patients with frequent to constant LBP symptoms tended to have a more marked sEMG response in comparison to patients with occasional to intermittent LBP. This is the first study demonstrating neuromuscular reflex responses associated with MFMA SMT in patients with LBP.
Reference: Christopher J. Colloca, D.C.1, Tony S. Keller, Ph.D. 2, Daryn E. Seltzer, D.C.3, Arlan W. Fuhr, D.C.1; Lumbar Erector Spinae Reflex Responses to Mechanical Force, Manually- Assisted Thoracolumbar and Sacroiliac Joint Manipulation in Patients with Low Back Pain; Proceedings of the 2000 International Conference on Spinal Manipulation, Bloomington, MN September 21-23,2000.
1 Postdoctoral & Related Professional Education Department Faculty, Logan College of Chiropractic, St, Louis, MO, USA; National Institute of Chiropractic Research, Phoenix, AZ, USA; Private Practice of Chiropractic, Phoenix, AZ, USA. 2 Professor, Department of Mechanical Engineering & Department of Orthopedics and Rehabilitation, The University of Vermont, Burlington, VT, USA. 3 National Institute of Chiropractic Research, Phoenix, AZ, USA; Private Practice of Chiropractic, Phoenix, AZ, USA.