Statistical morphological analysis reveals characteristic paraspinal muscle asymmetry in unilateral lumbar disc herniation

Abstract

Growing evidence suggests an association of lumbar paraspinal muscle morphology with low back pain (LBP) and lumbar pathologies. Unilateral spinal disorders provide unique models to study this association, with implications for diagnosis, prognosis, and management. Statistical shape analysis is a technique that can identify signature shape variations related to phenotypes but has never been employed in studying paraspinal muscle morphology. We present the first investigation using this technique to reveal disease-related paraspinal muscle asymmetry, using MRIs of patients with a single posterolateral disc herniation at the L5-S1 spinal level and unilateral leg pain. Statistical shape analysis was conducted to reveal disease- and phenotype-related morphological variations in the multifidus and erector spinae muscles at the level of herniation and the one below. With the analysis, shape variations associated with disc herniation were identified in the multifidus on the painful side at the level below the pathology while no pathology-related asymmetry in cross-sectional area (CSA) and fatty infiltration was found in either muscle. The results demonstrate higher sensitivity and spatial specificity for the technique than typical CSA and fatty infiltration measures. Statistical shape analysis holds promise in studying paraspinal muscle morphology to improve our understanding of LBP and various lumbar pathologies.

PILLAR: ParaspInaL muscLe segmentAtion pRoject - a comprehensive online resource to guide manual segmentation of paraspinal muscles from Magnetic Resonance Imaging

“…While it is important to compare left and right sides to help with the general shape, they may not always be exactly the same. Of note, differences in MF and ES shape between males and females have also been reported [21,22].…”

“…The presence of LBP and lumbar pathologies has been associated with paraspinal muscle atrophy (e.g., reduced size) and side-to-side asymmetry [19][20][21]. In some cases, this can also make paraspinal muscle segmentation more di cult.…”

The association between morphological characteristics of paraspinal muscle and spinal disorders

“…According to Xiao et al. there were no significant differences in CSA asymmetry at L5-S1 and S1 or in side-to-side variations of FI in patients with unilateral LDH [ 144 ]. Yazici et al.…”

Uncertainty-aware transformer model for anatomical landmark detection in paraspinal muscle MRIs

“…With recent interests in investigating the link between the morphological alterations of paraspinal muscles (i.e., multifidus and erector spinae) and low back pain (LBP), one of the most common musculoskeletal problems in adults worldwide, there is a new need for advanced morphometric analysis of these muscles, where inter-subject registration of their MRIs is required. 1 However, unlike brain MRIs, for which morphometric analyses have been widely employed to study related diseases and natural aging, intersubject affine registration using conventional similarity metrics (e.g., cross-correlation) for paraspinal muscle MRIs is more challenging due to highly complex image content, and high anatomical variability. 1,2 Thus, Landmark-based registration is helpful to tackle this issue.…”

“…1 However, unlike brain MRIs, for which morphometric analyses have been widely employed to study related diseases and natural aging, intersubject affine registration using conventional similarity metrics (e.g., cross-correlation) for paraspinal muscle MRIs is more challenging due to highly complex image content, and high anatomical variability. 1,2 Thus, Landmark-based registration is helpful to tackle this issue. 3,4 However, the more common approach, manual identification of anatomical landmarks, is still a highly time-consuming task and can be subject to inter-and intra-rater inconsistency.…”