Suzanne J Snodgrass1, Christopher Croker2, Meghana Yerrapothu3, Samala Shepherd4, Peter Stanwell5, Carl Holder6, Chris Oldmeadow7, James Elliott8. 1. School of Health Sciences, The University of Newcastle, University Drive, Callaghan, 2308, Australia. Electronic address: Suzanne.Snodgrass@newcastle.edu.au. 2. School of Health Sciences, The University of Newcastle, University Drive, Callaghan, 2308, Australia. Electronic address: Christopher.Croker@uon.edu.au. 3. Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. Electronic address: myerr95@gmail.com. 4. School of Health Sciences, The University of Newcastle, University Drive, Callaghan, 2308, Australia. Electronic address: Samala.Shepherd@uon.edu.au. 5. School of Health Sciences, The University of Newcastle, University Drive, Callaghan, 2308, Australia. Electronic address: Peter.Stanwell@newcastle.edu.au. 6. Clinical Research Design, IT and Statistical Support (CReDITSS), Hunter Medical Research Institute, New Lambton Heights, Australia. Electronic address: Carl.Holder@hmri.org. 7. Clinical Research Design, IT and Statistical Support (CReDITSS), Hunter Medical Research Institute, New Lambton Heights, Australia. Electronic address: Christopher.Oldmeadow@hmri.org. 8. Northern Sydney Local Health District & Faculty of Health Sciences, The University of Sydney Australia, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. Electronic address: Jim.Elliott@sydney.edu.au.
Abstract
BACKGROUND: Neck muscle compositional changes may represent potential biomarkers contributing towards chronic neck-related pain and disability. OBJECTIVES: To determine differences in muscle volume in the cervical muscles of individuals with chronic idiopathic neck pain compared with age- and sex-matched asymptomatic individuals, and to determine if these muscle variables relate to spinal level, side (left or right), age, sex, body mass index (BMI) or muscle strength. STUDY DESIGN: Cross-sectional magnetic resonance imaging (MRI) study. METHODS: Muscle volume of five muscle (groups) from cervical levels C3-T1 in 20 pain and 17 asymptomatic participants were quantified using MRI: levator scapulae, multifidus including semispinalis cervicis, semispinalis, splenius capitus including splenius cervicis, and sternocleidomastoid. Isometric extensor and flexor muscle strength were assessed with a dynamometer. Linear mixed modelling determined differences between groups in muscle volume accounting for participant characteristics. RESULTS: Individuals with pain had greater muscle volume (adjusted mean difference 71.2 mm3 (95% CI 14.2-128.2, p = .015) of the sternocleidomastoid, accounting for spinal level, side, muscle group (extensors vs flexor), sex, age, body mass index and strength. Modelling indicated muscle volume differed between spinal levels (p < .001); greater extensor muscle strength was associated with greater volume (p = .011); female sex (p < .001) and older age (p = .012) were associated with less volume. CONCLUSION: Between-group differences in cervical flexor muscle volume, and volume differences across spinal levels and muscles suggest the contribution of cervical muscles to chronic idiopathic neck pain is multifaceted and complex.
BACKGROUND: Neck muscle compositional changes may represent potential biomarkers contributing towards chronic neck-related pain and disability. OBJECTIVES: To determine differences in muscle volume in the cervical muscles of individuals with chronic idiopathic neck pain compared with age- and sex-matched asymptomatic individuals, and to determine if these muscle variables relate to spinal level, side (left or right), age, sex, body mass index (BMI) or muscle strength. STUDY DESIGN: Cross-sectional magnetic resonance imaging (MRI) study. METHODS: Muscle volume of five muscle (groups) from cervical levels C3-T1 in 20 pain and 17 asymptomatic participants were quantified using MRI: levator scapulae, multifidus including semispinalis cervicis, semispinalis, splenius capitus including splenius cervicis, and sternocleidomastoid. Isometric extensor and flexor muscle strength were assessed with a dynamometer. Linear mixed modelling determined differences between groups in muscle volume accounting for participant characteristics. RESULTS: Individuals with pain had greater muscle volume (adjusted mean difference 71.2 mm3 (95% CI 14.2-128.2, p = .015) of the sternocleidomastoid, accounting for spinal level, side, muscle group (extensors vs flexor), sex, age, body mass index and strength. Modelling indicated muscle volume differed between spinal levels (p < .001); greater extensor muscle strength was associated with greater volume (p = .011); female sex (p < .001) and older age (p = .012) were associated with less volume. CONCLUSION: Between-group differences in cervical flexor muscle volume, and volume differences across spinal levels and muscles suggest the contribution of cervical muscles to chronic idiopathic neck pain is multifaceted and complex.