Cervical Spinal Alignment Change Accompanying Spondylosis Exposes Harmonization Failure with Total Spinal Balance: A Japanese Cohort Survey Randomly Sampled from a Basic Resident Registry

The relationship between spinal posture and quality of life has garnered considerable attention with the increase in older community-dwelling residents. However, details of this association remain insufficient. A recent Japanese population cohort epidemiological locomotion survey (the Obuse study) revealed that the C2–C7 cervical sagittal vertical axis (CSVA) began to increase in males from their 60s, but not in females. This study aimed to clarify the pathology of these cervical spondylotic changes. A total of 411 participants (202 male and 209 female) aged between 50 and 89 years were selected by random sampling from a cooperating town’s resident registry. All participants underwent lateral X-ray photography in a standing position for the measurement of several sagittal spinal alignment parameters, including CSVA, C2–C7 cervical lordosis (CL), T1 slope (T1S), and sagittal vertical axis (SVA). The presence of cervical spondylotic changes was also recorded. Associations of cervical sagittal spinal alignment with cervical spondylosis and between cervical and total sagittal spinal alignment were examined. The prevalence of cervical spondylosis was significantly higher in males (81%) than in females (70%) (p = 0.01). CL was significantly smaller in cervical spondylosis subjects when adjusted by age (3.4 degrees less; p = 0.01). T1S minus CL displayed a moderate positive correlation with CSVA in both males and females (r = 0.49 and 0.48, respectively, both p < 0.01). In males only, CSVA and CL showed weak positive correlations with SVA (r = 0.31 and 0.22, respectively, both p < 0.01) independently of age. Cervical spinal misalignment was more clearly associated with diminished SF-8TM scores in females than in males. In community-dwelling elderly residents, cervical sagittal spinal alignment change accompanying cervical spondylosis manifested as hypofunction to compensate for whole-spine imbalance.

Cervical Spine Alignment in the Sagittal Axis: A Review of the Best Validated Measures in Clinical Practice

Study Design: Review of the best-validated measures of cervical spine alignment in the sagittal axis. Objective: Describe the C2-C7 Cobb Angle, C2-C7 sagittal vertical axis, chin-brow to vertical angle, T1 slope minus C2-C7 lordosis, C2 slope, and different types of cervical kyphosis. Methods: Search PubMed for recent technical literature on radiograph-based measurements of the cervical spine. Results: Despite the continuing use of measures developed many years ago such as the C2-C7 Cobb angle, there are new radiographic parameters being published and utilized in recent years, including the C2 slope. Further research is needed to compare older and newer measures for cross-validation. Utilizing these measures to determine the degree of correction intraoperatively and postoperatively will enable surgeons to optimize patient-level outcomes. Conclusion: Cervical spinal deformity can be a debilitating condition characterized by cervical spinal misalignment that affects the elderly more commonly than young populations. Many of these validated measures of cervical spinal alignment are useful in clinical settings due to their ease of implementation and correlations with various postoperative and health-related quality of life outcomes.

The Effect of T1-Slope in Spinal Parameters After Cervical Disc Arthroplasty

BACKGROUND Although patients with cervical kyphosis are not ideal candidates for cervical disc arthroplasty (CDA), there is a paucity of data on patients with a straight or slightly lordotic neck. OBJECTIVE To correlate cervical lordosis, T1-slope, and clinical outcomes of CDA. METHODS The study retrospectively analyzed 95 patients who underwent 1-level CDA and had 2-yr follow-up. They were divided into a high T1-slope (≥28°) group (HTSG, n = 45) and a low T1-slope (&lt;28°) group (LTSG, n = 50). Cervical spinal alignment parameters, including T1-slope, cervical lordosis (C2-7 Cobb angle), and segmental mobility (range of motion [ROM]) at the indexed level, were compared. The clinical outcomes were also assessed. RESULTS The mean T1-slope was 28.1 ± 7.0°. After CDA, the pre- and postoperative segmental motility remained similar and cervical lordosis was preserved. All the clinical outcomes improved after CDA. The HTSG were similar to the LTSG in age, sex, segmental mobility, and clinical outcomes. However, the HTSG had higher cervical lordosis than the LTSG. Furthermore, the LTSG had increased cervical lordosis (ΔC2-7 Cobb angle), whereas the HTSG had decreased lordosis after CDA. Patients of the LTSG, who had more improvement in cervical lordosis, had a trend toward increasing segmental mobility at the index level (ΔROM) than the HTSG. CONCLUSION In this series, T1-slope correlated well with global cervical lordosis but did not affect the segmental mobility. After CDA, the changes in cervical lordosis correlated with changes in segmental mobility. Therefore, segmental lordosis should be cautiously preserved during CDA as it could determine the mobility of the disc.

Relationship Between Cervical, Thoracic, and Lumbar Spinal Alignments in Automotive Seated Posture

The purpose of this study was to investigate the relationship between cervical, thoracic, and lumbar spinal alignments in one automotive occupant seated posture. An image dataset of the spinal column in the automotive seated posture, previously acquired by an upright open magnetic resonance imaging (MRI) system, was re-analyzed in this study. Spinal alignments were presented by the geometrical centers of the vertebral bodies extracted from the image data. Cervical, thoracic, and lumbar spinal alignments were analyzed separately with multidimensional scaling (MDS). Based on distribution maps of cervical, thoracic, and lumbar spinal alignments created by MDS, representative spinal alignment patterns of the cervical, thoracic, and lumbar spines and the relationship between cervical, thoracic, and lumbar spinal alignments were investigated. As a result, this study found a correlation between cervical and thoracic spinal alignments in an automotive occupant seated posture. According to representative spinal alignment patterns illustrated by the distribution map of spinal alignments, subjects who had kyphotic cervical spinal alignment tended to have less kyphotic thoracic spinal alignment, while subjects who had lordotic cervical spinal alignment tended to have more kyphotic thoracic spinal alignment. For lumbar spinal alignments, no prominent relationship was found between cervical and thoracic spinal alignment in the seated condition of this study.