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CERVICAL SPINE
From UCI Health in Orange County, California.
Evaluating Cervical Alignment The cervical spine is notable for its intricate complexity and holds the greatest range of motion in the entire spine while also offering robust support and stability for the head. However, Yu-Po Lee, MD the balance increases as people age, manifesting in degenerative changes affecting both the discs and the facet joints. These changes alter cervical spine alignment and can lead to pain. Cervical spondylotic myelopathy is a degenerative condition of the cervical spine. The prevalent hypothesis attributes such myelopathy to the onset of disc and facet joint degeneration that cause disc bulging and bone spurs that thus impinge on the spina l cord and ner ve roots. However, some recent studies suggest that cervical sag it ta l a l ig n ment ca n cause cer v ica l myelopathy. Evaniew et al performed a prospect ive study on 250 pat ients who presented with cervical myelopathy.1 The authors found that an increased cervical sagittal vertical axis (cSVA) measured from C2-7 and T1 slope were associated with inferior health-related qualit y of life at presentation among patients with CSM, but no significant associations were observed following surgical treatment. At 12 months after surger y, there were no significant associations between alignment parameters, changes in alignment, or shifts in health-related quality of life, function, or
Fall 2023
Vertebral Columns
symptoms. This observation is echoed in additional research, such as the retrospective study by Lin et al, which reinforced the correlation between increased disability and alterations in cervical alignment parameters on 90 patients who had surgery for cervical spondylotic myelopathy. 2 The authors noted that the disability of the neck increased with increasing C2-C7 SVA and T1S-CL and decreasing cervical lordosis before surgical reconstruction. Further research delves into the impact of cervical sagittal alignment on postoperative outcomes following cervical spine surgery. Hyun et al performed a retrospective study on 38 patients who underwent posterior cer v ica l decompression and f usion for cervical myelopathy. 3 The authors found that disability of the neck increased with cervical sagittal malalignment after cervical spine surgery and that a greater T1S-CL mismatch was associated with a greater degree of cervical malalignment. Specifically, a mismatch greater than 26.1° corresponded to positive cervical sagittal malalignment, defined as C2-C7 SVA greater than 50 mm. The evaluation of sagittal alignment of the cervical spine is determined by measuring the cer vical sagittal vertical axis (SVA), which is determined by measuring the distance between either the C2 or C7 plumb line, and using a vertical line drawn from the posterior superior corner of the sacrum. The cervical SVA (C2 SVA) has also be described
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