Test-Retest Reliability of Ultrasound Imaging of Lumbar Multifidus Muscle

Background to the study: Muscle strength and muscle size measurement are useful indicator of musculoskeletal pathology but it seems difficult at the moment to isolate individual paravertebral muscle for strength testing. It may therefore be useful to measure muscle size which can be achieved in vivo using diagnostic imaging technique. Purpose of the study: The purpose of this study is to demonstrate test-retest reliability of using diagnostic ultrasound imaging in the assessment of multifidus cross sectional area (CSA). Materials and method: Five apparently healthy volunteers (2 males 3 females) whose ages ranged from 23 to 35 years participated in this study. FF Sonic UF-750XT diagnostic ultrasound imaging machine with a 5MHz curvilinear transducer was used for ultrasound imaging oflumbar multifidus muscle. Results: The results shows that the average scores of lumbar multifidus ranged from 5.3cm2 to 8.6cm2. The test retest reliability for measuring lumbar multifidus on both single (0.996) and average measures (0.999) was good (P< 0.05). Conclusion: Ultrasound imaging could be said to be a reliable method that could be used by physiotherapist in evaluating multifidus muscle size which in turn could be a useful guide to the assessment of the effects of low back pain (LBP) and in the evaluation of the efficacy of common therapeutic intervention for LBP disorders. KEY WORDS: Multifidus, Reliability, Ultrasound Imaging