Relationship between low back pain and lumbar multifidus size at different postures

Area of Science:

• Musculoskeletal imaging
• Biomechanical analysis
• Clinical anatomy

Background:

• Ultrasound imaging has demonstrated utility in assessing acute low back pain (LBP) patients, primarily at rest.
• Previous research has not extensively explored multifidus muscle responses across various postures in chronic LBP.

Purpose of the Study:

• To compare the changes in cross-sectional area (CSA) of the multifidus muscle in individuals with and without chronic LBP.
• To investigate how different postures affect multifidus muscle CSA in both healthy and chronic LBP populations.

Main Methods:

• A prospective study involving 35 male adults (19 healthy, 16 with chronic LBP).
• Ultrasound imaging was used to measure multifidus CSA at L4 and L5 levels bilaterally.
• Measurements were taken in four postures: prone lying, upright standing, and 25 and 45 degrees of forward stooping.

Main Results:

• In healthy subjects, multifidus CSA increased from prone to standing and then decreased with forward stooping.
• Chronic LBP patients exhibited a reverse pattern, with maximum CSA occurring at 25 degrees of forward stooping.
• Significant differences in multifidus CSA response to postural changes were observed between the groups.

Conclusions:

• Multifidus muscle exhibits maximal contraction at upright standing in healthy individuals, but at 25 degrees forward stooping in chronic LBP patients.
• The functional role of the multifidus muscle in lumbar spine stabilization may be altered in individuals with chronic LBP.
• Assessing multifidus muscle size changes in response to different postures is a valuable diagnostic approach for LBP.