In this case report, physiotherapists measure the response of a single muscle to treatment using spinal manipulation for low back pain (LBP). The patient was a 33-year old man who had a long history of LBP and leg pain.

A special noninvasive method was used to measure function of the lumbar multifidus (LM) muscle before and after spinal manipulation. The LM is a deep spinal muscle. It goes from the base of the skull down to the sacrum. The LM provides stability and stiffness to the spine. This helps reduce wear and tear on the joints.

Rehabilitative ultrasound imaging (RUSI) allows the therapist to assess thickness and function of soft tissues such as muscles. Imaging of the LM at the L45 and L5-S1 levels was done before and right after spinal manipulation. RUSI was repeated one day later.

Measuring a change in muscle thickness is a way to assess muscle activation. In this case, the first measurement (before manipulation) showed poor activation of the LM.

Thickness and function of the muscle increased after spinal manipulation. Improvements were seen right away and continued for the first 24-hours. The greatest change occurred at the L4-5 level. The patient reported decreased stiffness and greater ease during movement.

It appears that spinal manipulation may affect LM muscle function.
The authors conclude that RUSI can be used to measure changes in LM muscle size before and after treatment. Changes can be observed and measured during the follow-up period. Differences in muscle thickness may be a good measure of muscle performance and can be used to assess outcomes of treatment.

Alexander K. Brenner, PT, MPT, OCS, et al. Improved Activation of Lumbar Multifidus Following Spinal Manipulation: A Case Report Applying Rehabilitative Ultrasound Imaging. Journal of Orthopaedic & Sports Physiotherapy. October 2007. Vol. 37. No. 10. Pp. 613-619.