Improved activation of lumbar multifidus following spinal manipulation: a case report applying rehabilitative ultrasound imaging

Case report. The use of spinal manipulation as a treatment to facilitate neuromuscular control of the paraspinal musculature is not well described in the literature. The use of rehabilitative ultrasound imaging (RUSI) may offer a convenient way to investigate and document possible changes occurring in the lumbar multifidus associated with manipulation intervention. The patient was a 33-year-old male with a 21-year history of low back pain and left posterior thigh pain who presented with lumbar hypomobility and met a previously published clinical prediction rule for spinal manipulation. During examination, the patient was asked to perform a prone upper extremity lifting task to assess activation in the lumbar multifidus during an automatic task. Through palpation the examiner noted a decreased contraction of the left multifidus between L4-S1 compared to the right. To explore this further, a decision was made to assess the multifidus with RUSI, which confirmed the activation deficit noted during palpation. A lumbar regional manipulation was performed with the intention of reducing spinal hypomobility and of assessing changes in multifidus activation. Imaging of the multifidus muscles at the L4-5 and L5-S1 levels were obtained premanipulation, immediately postmanipulation, and 1 day after manipulation. An increased ability to thicken the multifidus during a prone upper extremity lifting task was noted immediately and 1 day after manipulation. Average percent change in thickness at the L4-5 and L5-S1 levels with the prone arm lift was 3.6% premanipulation, 17.2% immediately postmanipulation, and 20.6% approximately 24 hours postmanipulation. Improvements in the thickening of the multifidus muscle during the upper extremity lifting task were greater than 3 standard errors of the measurement. Other changes included immediate palpable improvement in the contraction of the multifidus during the upper extremity lifting task, along with the patient report of increased ease of lifting. In this case report we quantified the short-term influence of spinal manipulation on multifidus muscular activation using RUSI. No cause-and-effect claims can be made; however, the results provide preliminary evidence to suggest that spinal manipulation may influence multifidus muscle function. RUSI offers a convenient way to investigate and document these changes.