title: Diagnostic Ultrasound as a Reliable Tool to Measure Multifidus Thickness
Creators: name: Shigemoto, Katherine
name: Arteaga, Valeria Garcia
name: Peterson, Jessie
name: Gentry, Nathan
Publisher: name: University of Nevada, Las Vegas
Year: 2022

description: Introduction: Lower back pain (LBP) is a recurrent issue in the general population, though it is generally seen 2-3 times more frequently in those who undergo transfemoral amputations, being considered worse than phantom limb or residual pain. It is suggested that LBP is more common in those who have a transfemoral amputation than those who have a transtibial amputation. Research thus far has seemed to focus on identifying links between unilateral amputation and LBP rather than bilateral.

The multifidus muscle is the most important dynamic stabilizer of the lumbar spine, accounting for two- thirds of lower lumbar segmental stability. A contributor to this pain may be multifidus muscle atrophy and an increase in intramuscular fat deposits and fibrous tissue infiltration, resulting in increased total muscle thickness with decreased multifidus activation and function, reducing dynamic stability capabilities and contributing to LBP. However, a lack of research in this population has led to an inconclusive explanation of the underlying mechanisms that may cause LBP. Typically, magnetic resonance imaging (MRI) is used as the gold standard to assess the thickness of the multifidus muscle, but it is costly and not as accessible to clinicians and patients. Ultrasound imaging (USI) can instead be used to assess multifidus thickness and it is reliable in the general population. Although extensive research has been performed in the general population, the reliability of diagnostic ultrasound imaging for multifidus thickness in populations who have undergone transfemoral amputations has not been studied. The purpose of this study was to evaluate intra-rater reliability of multifidus thickness measurements utilizing USI. Establishing reliability of USI in people with lower extremity amputations will allow us to confidently investigate any association between multifidus thickness and LBP.

Methods: Eleven participants who had undergone a unilateral transfemoral amputation at least one year prior to testing were recruited in the Las Vegas area for this intra-rater reliability study.

USI Procedure: Each participant was scheduled for two separate sessions, at least two days apart, but no more than 10. One examiner at the University of Nevada, Las Vegas, independently recorded the ultrasound images and measurements of the multifidus muscle.

Results: The reliability was excellent (ICC: .985 confidence interval was within an acceptable range of .955 to .995. The SEM ranged from .152 cm to .157 cm, and the MDC ranged from .421 cm to .435 cm.

Conclusion: This study showed that the intra-rater reliability of the measurements of the multifidus muscle thickness using diagnostic ultrasound imaging between two sessionsshowed excellent reliability. These results suggest that diagnostic ultrasound imaging is a reliable tool for measuring multifidus thickness in those with unilateral transfemoral amputations. Utilizing USI as a tool to measure multifidus muscle thickness will allow for further investigation regarding the association of multifidus muscle thickness and lower back pain in this patient population.