phaidra.vetmeduni.ac.at o:4450 DOI 10.1016/j.jbiomech.2024.111928 The assessment of paraspinal muscle epimuscular fat in participants with and without low back pain: A case-control study It remains unclear whether paraspinal muscle fatty infiltration in low back pain (LBP) is i) solely intramuscular, ii) is lying outside the epimysium between the muscle and fascial plane (epimuscular) or iii) or combination of both, as imaging studies often use different segmentation protocols that are not thoroughly described. Epimuscular fat possibly disturbs force generation of paraspinal muscles, but is seldomly explored. This project aimed to 1) compare epimuscular fat in participants with and without chronic LBP, and 2) determine whether epimuscular fat is different across lumbar spinal levels and associated with BMI, age, sex and LBP status, duration or intensity. Fat and water lumbosacral MRIs of 50 chronic LBP participants and 41 healthy controls were used. The presence and extent of epimuscular fat for the paraspinal muscle group (erector spinae and multifidus) was assessed using a qualitative score (0–5 scale; 0 = no epimuscular fat and 5 = epimuscular fat present along the entire muscle) and quantitative manual segmentation method. Chi-squared tests evaluated associations between qualitative epimuscular fat ratings and LBP status at each lumbar level. Bivariate and partial spearman’s rho correlation assessed relationships between quantitative and qualitative epimuscular fat with participants’ characteristics. Epimuscular fat was more frequent at the L4-L5 (X2 = 13.781, p = 0.017) and L5-S1 level (X2 = 27.825, p < 0.001) in participants with LBP compared to controls, which was not found for the higher lumbar levels. The total qualitative score (combined from all levels) showed a significant positive correlation with BMI, age, sex (female) and LBP status (r = 0.23–0.55; p < 0.05). Similarly, the total area of epimuscular fat (quantitative measure) was significantly correlated with BMI, age and LBP status (r = 0.26–0.57; p < 0.05). No correlations were found between epimuscular fat and LBP duration or intensity. Paraspinal muscle epimuscular fat is more common in chronic LBP patients. The functional implications of epimuscular fat should be further explored. eng Low Back Pain Magnetic Resonance Imaging Paraspinal Muscles Epimuscular Fat 2025-10-10T08:46:00.049Z LOMv1.0 Author BEGIN:VCARD VERSION:3.0 N:Rosenstein;Brent; FN:Brent Rosenstein END:VCARD BEGIN:VCARD VERSION:3.0 N:Burdick;Jessica; FN:Jessica Burdick END:VCARD BEGIN:VCARD VERSION:3.0 N:Roussac;Alexa; FN:Alexa Roussac END:VCARD BEGIN:VCARD VERSION:3.0 N:Rye;Meaghan; FN:Meaghan Rye END:VCARD BEGIN:VCARD VERSION:3.0 N:Naghdi;Neda; FN:Neda Naghdi END:VCARD BEGIN:VCARD VERSION:3.0 N:Valentin;Stephanie; FN:Stephanie Valentin END:VCARD BEGIN:VCARD VERSION:3.0 N:Licka;Theresia; FN:Theresia Licka X-ORCID:https://orcid.org/0000-0001-7651-5180 END:VCARD BEGIN:VCARD VERSION:3.0 N:Sean;Monica; FN:Monica Sean END:VCARD BEGIN:VCARD VERSION:3.0 N:Tétreault;Pascal; FN:Pascal Tétreault END:VCARD BEGIN:VCARD VERSION:3.0 N:Elliott;Jim; FN:Jim Elliott END:VCARD BEGIN:VCARD VERSION:3.0 N:Fortin;Maryse; FN:Maryse Fortin END:VCARD https://w3id.org/kim/hcrt/scheme https://w3id.org/kim/hcrt/text Textdokument Text LOMv1.0 yes https://creativecommons.org/licenses/by-nc-nd/4.0 application/pdf 4427003 https://phaidra.vetmeduni.ac.at/o:4450 https://phaidra.vetmeduni.ac.at/api/object/o:4450/thumbnail LOMv1.0 discipline