The Impact of Cervical Spinal Muscle Degeneration on Cervical Sagittal Balance and Spinal Degenerative Disorders

Abstract

Study Design: This is a retrospective analysis of kinematic magnetic resonance images (kMRI). Objective: To assess the association of cervical paraspinal muscle with cervical sagittal balance and degenerative spinal disorders. Summary of Background Data: Although the effects of spinal disorders and cervical imbalance on patient’s symptoms have been well described, the relationship of the cervical muscle quality and volume to cervical imbalance or spinal disorders is not well established. Materials and Methods: In total, 100 kMRI taken in a neutral weight-bearing position were analyzed. The adjusted cross-sectional area ratio (aCSA ratio: the value of muscle CSA divided by the vertebral CSA) and fat infiltration ratio of the transversospinalis muscles at C4 and C7 vertebral levels were measured using axial slice of kMRI. The correlation with cervical balance parameters [Oc–C2 angle, C2–C7 angle, C7–T1 angle, C7 slope, T1 slope, cranial tilt, cervical tilt, thoracic inlet angle (TIA), and neck tilt] and cervical degenerative disorders (disk degeneration, Modic change, and spondylolisthesis) were evaluated. Results: The aCSA ratio at C4 correlated with C2–C7 angle (r=0.267), C7 slope (r=0.207), T1 slope (r=0.221), disk degeneration at C3–4, C4–5, C5–6 (r=−0.234, −0.313, −0.262) and spondylolisthesis at C3 (anterior: r=−0.206, posterior: r=−0.249). The aCSA ratio at C7 correlated with disk degeneration at C3–4, C4–5, C5–6, C6–7 (r=−0.209, −0.294, −0.239, −0.209). The fat infiltration ratio at C4 correlated with TIA (r=0.306) and neck tilt (r=0.353), likewise the ratio at C7 correlated with TIA (r=0.270) and neck tilt (r=0.405). All correlations above were statistically significant with P<0.05. Conclusions: The paraspinal muscle volume showed significant relationship with the cervical balance parameters and disk degeneration. While, paraspinal muscle quality related to the thoracic inlet parameters. Our findings can be an important step to develop the knowledge of the association between cervical muscle and cervical degenerative disorders, as well as the sagittal balance of the cervical spine. Level of Evidence: Level III.

The relationship of global sagittal malalignment to fatty infiltration in the aging spine

“…Older age and higher BMI were associated with FI of the PVM, helping to validate the novel method used to measure FI in this investigation, given that such associations have been corroborated by past research [12,18]. Investigators have employed both MRI-and CT-based techniques to assess the quality of the PVM [13,18,20]. MRI-based modalities have quantified FI as a percentage of the PVM volume by using differences in the T2-weighted signals of fat and muscle tissue [13].…”

“…Investigators have employed both MRI-and CT-based techniques to assess the quality of the PVM [13,18,20]. MRI-based modalities have quantified FI as a percentage of the PVM volume by using differences in the T2-weighted signals of fat and muscle tissue [13]. On the other hand, CT-based studies have reported the "mean density" of the PVM (averaged density over a fixed contour) expressed in Hounsfield units (HU) [18], with a lower density corresponding to a fattier PVM.…”

“…Abnormal PVM has been demonstrated in patients with a variety of conditions, including low back pain, degenerative disc disease, and lumbar radiculopathy, and patients with degenerative lumbar scoliosis; investigators have shown asymmetry between musculature on opposite sides of the curve [8][9][10][11]. Muscular changes have also been demonstrated in regional sagittal deformities [8,10,[12][13][14], and relationships between fatty degeneration of lumbar PVM and increased global sagittal malalignment have previously been demonstrated [15]. However, given that global sagittal deformity encompasses the patient's compensatory changes in posture, it could be hypothesized that the PVM throughout the entire spine is abnormal in such cases of malalignment.…”

Impact of cervical sagittal parameters on axial neck pain in patients with cervical kyphosis

“…In previous studies, thoracic inlet parameters were found to exhibit a strong correlation with the other cervical parameters [14][15][16] . Therefore, assessing the impact of these parameters on ANP in the context of CK is a key imperative.…”

The impact of cervical sagittal parameters on axial neck pain in patients with cervical kyphosis

“…Previous researchers proved thoracic inlet parameters correlates highly with the other cervical parameters and had a critical effect on cervical sagittal alignment [14][15][16] . Therefore, it is necessary to discuss the impact of thoracic inlet parameters on ANP in CK.…”