Sequential sagittal alignment changes in the cervical spine after occipitocervical fusion

Abstract

BACKGROUND There are few studies regarding sequential changes in the sagittal alignment of the upper and lower cervical regions of the spine after occipitocervical fusion (OCF). In addition, no comparisons of cervical sagittal alignment (CSA) between patients with craniocervical junction disorders (CJDs) and normal populations have been reported. AIM To compare the CSA of patients with CJDs with that of normal controls and investigate the sequential changes in the CSA of the upper and lower cervical spine after OCF. METHODS Eighty-four patients who underwent OCF (OCF group) and 42 asymptomatic volunteers (control group) were included. Radiographic parameters, including the occipital to C2 angle (O-C2a), occipital and external acoustic meatus to axis angle (O-EAa), C2–7 angle (C2-7a), and pharyngeal inlet angle (PIA), were measured and compared pre- and postoperatively. The correlations among the parameters were analyzed using Pearson’s correlation test. RESULTS The O-C2a and PIA of the OCF group were smaller than those of the control group, while their O-EAa and C2-7a values were larger than those of the normal controls. There were no significant differences in O-C2a, C2-7a, or PIA in the OCF group at baseline, 1 mo, or the final follow-up after surgery. The Pearson’s correlation results showed that there were significant correlations between the O-C2a and C2Ta, C2-7a, C2-7 sagittal vertical axis (SVA), and PIA at 1 mo after OCF surgery and between O-C2a and O-EAa, C2Ta, C2-7a, C2-7 SVA, and PIA at the final follow-up. CONCLUSION Patients with CJDs have a more kyphotic upper CSA and a more lordotic lower CSA than normal controls. The effectiveness of OCF surgery in restoring CSA may be limited by the realignment of the craniocervical junction being neglected. The reduction in O-C2a after OCF surgery may increase C2-7a and decrease PIA.

Cauda equina syndrome caused by the application of DuraSealTM in a microlaminectomy surgery: A case report

“…As life expectancy increases worldwide, degenerative diseases of the lumbosacral spine are becoming more common[ 1 ]. Debilitating conditions are currently the major causes of morbidity, disability, and lost productivity[ 2 , 3 ].…”

Cervical Sagittal Alignment and Related Factor Analysis and Prediction Model in Patients Undergoing Revision Surgery After Anterior Cervical Fusion

“…The explanation is that as the C0-C2 angle decreases, the cranium's center of gravity shifts forward, requiring the lower spine's lordosis (CL) to drop to maintain the horizontal gaze. 21 However, the (C0-C2)-C2S mismatch between the revision and nonrevision surgery groups is a discovery that is new to us, and we do not yet have a good explanation. However, we concur with other authors 23 , 26 that alterations at C0-C2 and CL are a physiologic mechanism for maintaining horizontal gaze in response to thoracolumbar malalignment.…”

“…However, no notable differences in C0-C2 angle or C2S were found between the revision and nonrevision groups. Studies 20 , 21 have suggested that the normal value of C0-C2 angle should be in the range of 0 0 to 30 0 , in health individual, and more than 30 0 was reported to associate with complications such as dysphagia and cervical misalignment. In this study, all patients in revision and nonrevision groups have values of C0-C2 angle within the range of the health individual.…”