Magnetic resonance imaging study of cross-sectional area of the cervical extensor musculature in an asymptomatic cohort.
ABSTRACT Magnetic Resonance Imaging (MRI) can be regarded as the gold standard for muscle imaging; however there is little knowledge about in vivo morphometric features of neck extensor muscles in healthy subjects and how muscle size alters across vertebral segments. It is not known how body size and activity levels may influence neck muscle cross-sectional area (CSA) or if the muscles differ from left and right. The purpose of this study was to establish relative CSA (rCSA) data for the cervical extensor musculature with a reliable MRI measure in asymptomatic females within a defined age range and to determine if side-side and vertebral level differences exist. MRI of the cervical spine was performed on 42 asymptomatic female subjects within the age range of 18-45. The rCSA values for the cervical extensor muscles were measured from axial T1-weighted images. We found significant side-side rCSA differences for the rectus capitis posterior minor, major (P < 0.001), multifidus (P = 0.002), and the semispinalis cervicis/capitis (P = 0.001, P < 0.001). There were significant vertebral level differences in rCSA of the semispinalis cervicis/capitis, multifidus, splenius capitis, and upper trapezius (P < 0.001). Activity levels were shown to impact on the size of semispinalis cervicis (P = 0.027), semispinalis capitis (P = 0.003), and the splenius capitis (P = 0.004). In conclusion, measuring differences in neck extensor muscle rCSA with MRI in an asymptomatic population provides the basis for future study investigating relationships between muscular atrophy and symptoms in patients suffering from persistent neck pain. Clin.
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ABSTRACT: Study Design. A population based cross-sectional studyObjective. To clarify relative constituents of viable muscle in 2-dimensional cross sectional area (CSA) measures of ventral and dorsal cervical muscles in patients with chronic whiplash associated disorders (WAD), idiopathic neck pain, and healthy controls.Summary of Background Data. Previous data using T1-weighted MRI demonstrated large amounts of neck muscle fat infiltration and increased neck muscle CSA in patients with chronic WAD but not in idiopathic neck pain or healthy controls.Methods. MR images were obtained for 14 cervical muscle regions in 136 females, including 79 with chronic whiplash, 23 with chronic idiopathic neck pain, and 34 healthy controls.Results. Without fat removed, relative CSA (rCSA) of 7/14 muscle regions in the participants with chronic whiplash associated disorders (WAD) was larger, 3/14 smaller and 4/14 similar to healthy individuals. When T1-weighted signal representing the lipid content of these muscles was removed, 8/14 relative muscle CSA (rmCSA) in patients with whiplash were similar, 5/14 were smaller and only 1/14 was larger than those observed in healthy controls. Removal of fat from the rCSA measurement did not alter findings between participants with idiopathic neck pain and healthy controls.Conclusion. These findings clarify that previous reports of increased rCSA in patients with chronic whiplash represent cervical muscle pseudo-hypertrophy. rmCSA measures reveal atrophy in several muscles in both patients with WAD and idiopathic neck pain which supports inclusion of muscle conditioning in the total management of these patients.Spine 11/2013; · 2.45 Impact Factor
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ABSTRACT: To quantify the cervical muscle volume variation by means of three-dimensional reconstruction from MRI images. Sixteen subjects were scanned using a Philips MRI scanner, including 11 men and 5 women, aged from 23 to 33 years, weighting between 49-80 kg. The deformation of a parametric specific object method was used to develop three-dimensional muscle models from contours on a small number of MRI images. Six subjects were reconstructed by two observers for evaluating the reliability by means of intraclass correlation coefficient (ICC). The results were also compared with in vivo measurement on a single specimen from a reference literature. The difference in left and right muscles volumes was assessed with a paired Wilcoxon signed rank test. The results showed good reliability by means of ICC study and were consistent with the in vivo specimen measurements. The left and right paired muscle volumes showed no significant difference. Interindividual variance was large that could reach 364 cm(3) , but the ratio of a given muscle volume to the total volume was less variable, always lower than 13%. The maximum cross sectional areas of cervical muscles varied greatly between individuals and the maximum values were mostly found at the C6-C7 level. This study provides initial results which could be used as reference data for clinical evaluation and biomechanical model development.J. Magn. Reson. Imaging 2013. © 2013 Wiley Periodicals, Inc.Journal of Magnetic Resonance Imaging 10/2013; · 2.57 Impact Factor
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ABSTRACT: Object The objective of this study was to assess the cross-sectional areas (CSAs) of the superficial, deep flexor (DF), and deep extensor (DE) paraspinal muscles in patients with cervical spondylotic myelopathy (CSM), and to evaluate their correlations with functional status and sagittal spinal alignment changes following central corpectomy with fusion and plating. Methods In this retrospective study of 67 patients who underwent central corpectomy with fusion and plating for CSM, the CSAs of the paraspinal muscles were calculated on the preoperative T2-weighted axial MR images and computed as ratios with respect to the corresponding vertebral body areas (VBAs) and as flexor/extensor CSA ratios. These ratios were then compared with those in the normative population and analyzed with respect to various clinicoradiological factors, including pain status, Nurick grade, and segmental angle change at follow-up (SACF). Results The mean CSA values for all muscle groups and the DF/DE ratio were significantly lower in the study cohort compared with an age- and sex-matched normative study group (p < 0.001). Among various independent variables tested in a multivariate regression analysis, increasing age and female sex significantly predicted a lower total extensor CSA/VBA ratio (p < 0.001), while a longer duration of symptoms significantly predicted a greater total flexor/total extensor CSA ratio (p = 0.02). In patients undergoing single-level corpectomy, graft subsidence had a positive correlation with SACF in all patients (p < 0.05), irrespective of the preoperative segmental angle and curvature, while in patients undergoing 2-level corpectomy, graft subsidence demonstrated such a correlation only in the subgroup with lordotic curvatures (p = 0.02). Among the muscle area ratios, the DF/DE ratio demonstrated a negative correlation with SACF in the subgroup with preoperative straight or kyphotic segmental angles (p = 0.04 in the single corpectomy group, p = 0.01 in the 2-level corpectomy group). There was no correlation of any of the muscle ratios with change in Nurick grade. Conclusions Patients with CSM demonstrate significant atrophy in all the flexor and extensor paraspinal muscles, and also suffer a reduction in the protective effect of a strong DF/DE CSA ratio. Worsening of this ratio significantly correlates with greater segmental kyphotic change in some patients. A physiological mechanism based on DF dysfunction is discussed to elucidate these findings that have implications in preventive physiotherapy and rehabilitation of patients with CSM. Considering that the influence of a muscle ratio was significant only in patients with hypolordosis, a subgroup that is known to have facetal ligament laxity, it may also be postulated that ligamentous support supersedes the influence of paraspinal muscles on postoperative sagittal alignment in CSM.Journal of Neurosurgery Spine 05/2014; · 2.36 Impact Factor