Standardized provocation of lumbar spine mobility: three methods compared by radiostereometric analysis

Area of Science:

• Orthopedics
• Biomechanics
• Radiology

Background:

• Clinical assessment of lumbar spine kinematics is often confounded by pain and muscle spasm.
• Standardized methods are needed to accurately measure intervertebral mobility over time and between individuals.
• Previous standardized methods using traction-compression were found to provide insufficient mobility.

Purpose of the Study:

• To evaluate the validity of standardized provocations for assessing lower lumbar spine intervertebral mobility.
• To compare the mobility response of the lumbar spine to three distinct standardized positional changes.

Main Methods:

• Radiostereometric analysis (RSA) was employed to measure intervertebral mobility.
• Twelve adult patients with low back pain and degenerative disc disease were included.
• Mobility was assessed at the three most distal lumbar disc levels during transitions from supine to standing, loaded standing (20 kg), and sitting.

Main Results:

• The supine to sitting provocation yielded significantly greater sagittal mobility and vertical translations compared to standing and loaded standing.
• Vertical translations were comparable between sitting and loaded standing at the L3-L4 level.
• Transverse translations were minimal and did not significantly differ across the tested provocations.

Conclusions:

• Changing from a supine to a sitting position elicits a more pronounced intervertebral mobility response in the lumbar spine.
• The supine to sitting provocation increases mean lumbar mobility and can reveal mobility in cases where it is stable under other conditions.
• Combined with RSA, this method provides an enhanced approach for studying lumbar spine kinematics.