PILLAR: ParaspInaL muscLe segmentAtion pRoject - a comprehensive online resource to guide manual segmentation of paraspinal muscles from magnetic resonance imaging.

BACKGROUND: There is an increasing interest in assessing paraspinal morphology and composition in relation to low back pain (LBP). However, variations in methods and segmentation protocols contribute to the inconsistent findings in the literature. We present an on-line resource, the ParaspInaL muscLe segmentAtion pRoject (PILLAR, https://projectpillar.github.io/ ), to provide a detailed description and visual guide of a segmentation protocol by using the publicly available ITK-SNAP software and discuss related challenges when performing paraspinal lumbar muscles segmentations from magnetic resonance imaging (MRI). METHODS: T2-weighted and corresponding fat-water IDEAL axial MRI from 3 males and 3 females (2 chronic LBP and 1 control for each sex) were used to demonstrate our segmentation protocol for each lumbar paraspinal muscle (erector spinae, lumbar multifidus, quadratus lumborum and psoas) and lumbar spinal level (L1-L5). RESULTS: Proper segmentation requires an understanding of the anatomy of paraspinal lumbar muscles and the variations in paraspinal muscle morphology and composition due to age, sex, and the presence of LBP or related spinal pathologies. Other challenges in segmentation includes the presence and variations of intramuscular and epimuscular fat, and side-to-side asymmetry. CONCLUSION: The growing interest to assess the lumbar musculature and its role in the development and recurrence of LBP prompted the need for comprehensive and easy-to-follow resources, such as the PILLAR project to reduce inconsistencies in segmentation protocols. Standardizing manual muscle measurements from MRI will facilitate comparisons between studies while the field is progressively moving towards the automatization of paraspinal muscle measurements for large cohort studies.

Comparing assessment methods of low back pain related disability in student circus artists: A cross-sectional study.

BACKGROUND: Student circus artists put constant stress on their back. However, the presence of low back pain (LBP) and related disability in this population remains unclear. OBJECTIVES: To 1) examine LBP history in circus artists and compare related disability scores using the Oswestry Disability Index (ODI) and the Athlete Disability Index (ADI), and 2) examine the correlation between LBP-related disability scores, pain intensity and pain catastrophizing. METHODS: Thirty-three circus students completed an online survey on demographics, training history, and LBP. Participants reporting LBP filled the ODI, ADI, numerical pain rating scale (NPRS), and Pain Catastrophizing Scale (PCS). Descriptive statistics and Pearson's correlation coefficients were used to assess the correlations between the ODI, ADI, NPRS, and PCS. RESULTS: There was a significant positive correlation between the ODI and ADI (r= 0.77, p< 0.001) and between the NPRS and ADI (r= 0.52, p= 0.03), but no correlation between NPRS and ODI. While the PCS scores were significantly correlated with the NPRS ((r= 0.71; p< 0.001) and the ADI (r= 0.51; p= 0.032), no correlation was observed between the PCS and ODI scores (p= 0.088). Based on the ODI scores, 94.44% of the artists reporting LBP were classified with mild disability, 5.56% moderate, and 0% severe disability as compared to 66.67%, 27.78% and 5.55% with the ADI, respectively. CONCLUSION: Our study highlights the potential of the ADI as an effective tool for assessing LBP-related disability in circus artists, supported by a strong correlation with the NPRS.

Ultrasonography of the multifidus muscle in student circus artists with and without low back pain: a cross-sectional study.

BACKGROUND: Degenerative structural changes and functional deficits of the lumbar multifidus (LM) muscle were observed in athletes with low back pain. While spinal injuries are common in circus artists, there is no information on LM characteristics in this population. The aims of this study were to investigate LM morphology and function and explore the relationship between LM characteristics and low back pain in male and female circus artists. METHODS: 31 college circus students were recruited. Participants completed an online survey to acquire demographic data and low back pain history. Body composition was measured using multi-frequency bio-impedance analysis. Ultrasound examinations at the fifth lumbar vertebrae in prone and standing positions were performed to assess LM cross-sectional area, echo-intensity, thickness. Independent and dependent t-test assessed the difference between sex and side, respectively. The relationships between measures were assessed with Pearson's correlations. The LM characteristics' difference between artists with and without low back pain (group binary variable) was assessed with Analysis of covariance using lean body mass, height and % body fat as continuous covariates. RESULTS: Males had significantly larger LM cross-sectional area, lower echo-intensity and greater thickness change from rest to contracted than females. LM cross-sectional area asymmetry in prone was greater in artists reporting low back pain in the previous 4-weeks (p = 0.029) and 3-months (p = 0.009). LM measures were correlated with lean body mass, height, and weight (r = 0.40-0.77, p ≤ 0.05). CONCLUSION: This study provided novel insights into LM characteristics in circus artists. Greater LM asymmetry was observed in artists with a history of low back pain. In accordance with previous studies in athletes, LM morphology and function were highly correlated with body composition measurements.