A guide for standardized interpretation of lumbar multifidus ultrasonography; an observational study.

BACKGROUND: Inconsistent descriptions of Lumbar multifidus (LM) morphology were previously identified, especially in research applying ultrasonography (US), hampering its clinical applicability with regard to diagnosis and therapy. The aim of this study is to determine the LM-sonoanatomy by comparing high-resolution reconstructions from a 3-D digital spine compared to standard LM-ultrasonography. METHODS: An observational study was carried out. From three deeply frozen human tissue blocks of the lumbosacral spine, a large series of consecutive photographs at 78 µm interval were acquired and reformatted into 3-D blocks. This enabled the reconstruction of (semi-)oblique cross-sections that could match US-images obtained from a healthy volunteer. Transverse and oblique short-axis views were compared from the most caudal insertion of LM to L1. RESULTS: Based on the anatomical reconstructions, we could distinguish the LM from the adjacent erector spinae (ES) in the standard US imaging of the lower spine. At the lumbosacral junction, LM is the only dorsal muscle facing the surface. From L5 upwards, the ES progresses from lateral to medial. A clear distinction between deep and superficial LM could not be discerned. We were only able to identify five separate bands between every lumbar spinous processes and the dorsal part of the sacrum in the caudal anatomical cross-sections, but not in the standard US images. CONCLUSION: The detailed cross-sectional LM-sonoanatomy and reconstructions facilitate the interpretations of standard LM US-imaging, the position of the separate LM-bands, the details of deep interspinal muscles, and demarcation of the LM versus the ES. Guidelines for electrode positioning in EMG studies should be refined to establish reliable and verifiable findings. For clinical practice, this study can serve as a guide for a better characterisation of LM compared to ES and for a more reliable placement of US-probe in biofeedback.

Inconsistent descriptions of lumbar multifidus morphology: A scoping review.

BACKGROUND: Lumbar multifidus (LM) is regarded as the major stabilizing muscle of the spine. The effects of exercise therapy in low back pain (LBP) are attributed to this muscle. A current literature review is warranted, however, given the complexity of LM morphology and the inconsistency of anatomical descriptions in the literature. METHODS: Scoping review of studies on LM morphology including major anatomy atlases. All relevant studies were searched in PubMed (Medline) and EMBASE until June 2019. Anatomy atlases were retrieved from multiple university libraries and online. All studies and atlases were screened for the following LM parameters: location, imaging methods, spine levels, muscle trajectory, muscle thickness, cross-sectional area, and diameter. The quality of the studies and atlases was also assessed using a five-item evaluation system. RESULTS: In all, 303 studies and 19 anatomy atlases were included in this review. In most studies, LM morphology was determined by MRI, ultrasound imaging, or drawings - particularly for levels L4-S1. In 153 studies, LM is described as a superficial muscle only, in 72 studies as a deep muscle only, and in 35 studies as both superficial and deep. Anatomy atlases predominantly depict LM as a deep muscle covered by the erector spinae and thoracolumbar fascia. About 42% of the studies had high quality scores, with 39% having moderate scores and 19% having low scores. The quality of figures in anatomy atlases was ranked as high in one atlas, moderate in 15 atlases, and low in 3 atlases. DISCUSSION: Anatomical studies of LM exhibit inconsistent findings, describing its location as superficial (50%), deep (25%), or both (12%). This is in sharp contrast to anatomy atlases, which depict LM predominantly as deep muscle. Within the limitations of the self-developed quality-assessment tool, high-quality scores were identified in a majority of studies (42%), but in only one anatomy atlas. CONCLUSIONS: We identified a lack of standardization in the depiction and description of LM morphology. This could affect the precise understanding of its role in background and therapy in LBP patients. Standardization of research methodology on LM morphology is recommended. Anatomy atlases should be updated on LM morphology.

Functional and morphological lumbar multifidus characteristics in subgroups with low back pain in primary care.

BACKGROUND: Since the contribution of the lumbar multifidus(LM) is not well understood in relation to non-specific low back pain(LBP), this may limit physiotherapists in choosing the most appropriate treatment strategy. OBJECTIVES: This study aims to compare clinical characteristics, in terms of LM function and morphology, between subacute and chronic LBP patients from a large clinical practice cohort compared to healthy controls. DESIGN: Multicenter case control study. METHOD: Subacute and chronic LBP patients and healthy controls between 18 and 65 years of age were included. Several clinical tests were performed: primary outcomes were the LM thickness from ultrasound measurements, trunk range of motion(ROM) from 3D kinematic tests, and median frequency and root mean square values of LM by electromyography measurements. The secondary outcomes Numeric Rating Scale for Pain(NRS) and the Oswestry Disability Index(ODI) were administered. Comparisons between groups were made with ANOVA, p-values<0.05, with Tukey's HSD post-hoc test were considered significant. RESULTS: A total of 161 participants were included, 50 healthy controls, 59 chronic LBP patients, and 52 subacute LBP patients. Trunk ROM and LM thickness were significantly larger in healthy controls compared to all LBP patients(p < 0.01). A lower LM thickness was found between subacute and chronic LBP patients although not significant(p = 0.11-0.97). All between-group comparisons showed no statistically significant differences in electromyography outcomes (p = 0.10-0.32). NRS showed no significant differences between LBP subgroups(p = 0.21). Chronic LBP patients showed a significant higher ODI score compared to subacute LBP patients(p = 0.03). CONCLUSIONS: Trunk ROM and LM thickness show differences between LBP patients and healthy controls.

Reliability and validity of the Microgate Gyko for measuring range of motion of the low back.

BACKGROUND: The aim of this study was to test the inter- and intrarater reliability and the concurrent validity of the Gyko Microgate for the assessment of lumbar range of motion. METHODS: A cross-sectional study was carried out with two groups of healthy participants. The first group, consisting of 91 subjects, was tested to determine the inter- and intrarater reliability. Concurrent validity was assessed with comparisons with an optical motion system (Vicon) in a second group of 20 subjects. Lumbar range of motion in flexion, extension, left and right lateral flexion were performed. Intraclass correlation coefficient (ICC) was calculated for both analyses. Measurement error was calculated with standard error of the measurement (SEM), smallest detectable change (SDC) and Limits of Agreement (LoA). ICCs were considered good when ICC ≥0.80 and excellent with ICC ≥0.90. RESULTS: Interrater reliability was good to excellent with ICCs ranging from 0.82 to 0.94. Intrarater reliability was good to excellent with ICCs ranging from 0.84 to 0.95. Concurrent validity was excellent with ICCs varying from 0.90 to 0.95. LoA were highest in interrater reliability and smallest in concurrent validity. SEM ranged from 2.2 to 4.0° in lateral flexion left and flexion respectively. SDC varied from 6.1 to 11.1°. CONCLUSION: Gyko has good inter- and intrarater reliability and excellent concurrent validity compared to the optical motion system for lumbar range of motion. Gyko may be considered as objective measure to measure range of motion for clinical purposes, however trials with patients are currently lacking.