Evaluation of lumbar segmental motion using ultrasound imaging following common joint mobilization techniques

Spinal mobility is clinically important in managing mechanical low back pain. Manual methods are commonly used for diagnosis and treatment in orthopedic practice. This study quantified changes in sagittal plane lumbar segmental motion using ultrasound imaging (USI) following common joint mobilization techniques in asymptomatic individuals. Additionally, tibial H-reflexes and sagittal plane trunk motion in standing were evaluated for association with lumbar segmental motion.Participants aged ≤ 30 or ≥ 50 years were recruited from among students, faculty, and affiliates of the Department of Physical Therapy at Winston-Salem State University and randomized to receive L4 central posterior-to-anterior (CPA) mobilization or left lumbar rotation mobilization interventions. Joint laxity was assessed using the Beighton score, and standing sagittal plane trunk motion was measured using the fingertip-to-floor method. Lumbar segmental motion was evaluated using USI in neutral, extension, and flexion positions at baseline, immediately following joint mobilization, and following 5 minutes of prone resting. Tibial H-reflexes were measured at baseline, immediately following joint mobilization, and in real-time during CPA mobilization. The primary outcome was lumbar segmental motion analyzed by position, mobilization group, sex, age category, and Beighton risk.

Repeated measures ANOVA revealed significant increases in L4/5 flexion (p = .01, ƞ²=.21) and combined flexion and extension (p = .03, ƞ²=.15). These changes persisted following 5 minutes of prone resting, regardless of mobilization technique. Significant interactions between segmental motion, sex, and/or Beighton risk were observed.

Significant increases were observed in L4/5 flexion immediately following joint mobilization regardless of mobilization group, with significant statistical interactions observed between segmental motion, sex, and/or Beighton risk. This is the first investigation to demonstrate the value of USI for quantifying lumbar segmental motion following joint mobilization. Quantifying lumbar segmental motion helps clarify the underlying mechanisms of manual therapy. Future studies should include patients with low back pain.