BACKGROUND:. The majority of earlier studies of the parameters of sagittal balance did not consider the influence of spinal muscles on spinal sagittal a

We performed a retrospective analysis of medical records and radiographic images of patients who never underwent spinal treatment including diagnosis. The objective of this study is to explain the biomechanical and physiologic characteristics of cervical alignment related to thoracic inlet angle including T1 slope changes in each individual. We reviewed the cervical CT radiographs of 80 patients who visited ENT outpatient clinic without any symptom, diagnosis and treatment of cervical spine from January 2011 to September 2012. All targeted people were randomized without any prejudice. We assessed the data-T1 slope, Cobb's angle C2-7, neck tilt, sagittal vertical axis (SVA) C2-7 and thoracic inlet angle by the CT radiographs. The relationships between each value were analyzed and we concluded that Cobb's angle C2-7 gets higher as the T1 slope gets higher, while the SVA C2-7 value decreases. We propose that the T1 slope is background information in deciding how much angle can be made in the cervical spinal angle of surgical lordotic curvature, especially severe cervical deformity.

Study Design. Retrospective analysis. Objective. The main objectives of this study were to analyze and compare cervical sagittal parameters, including the T1 slope, in a population of 45 patients with degenerative cervical spondylolisthesis (DCS) and to compare these patients with a control group of asymptomatic population. Summary of Background Data. Sagittal balance in the cervical spine is as important as the pelvic incidence and is related to the concept of T1 slope. Compared with degenerative lumbar spondylolisthesis, there are few studies evaluating DCS, and characteristic changes of the cervical sagittal parameters (including T1 slope) in patients with DCS are not well studied. Methods. We identified 45 patients with DCS (5.8%) from a database of 767 patients, using cervical radiograph in a standing position. All had radiograph and computed tomographic scan at the same time. Cervical sagittal parameters were analyzed on computed tomographic scan in a standardized supine position. The following cervical sagittal parameters were measured: T1 slope, neck tilt, thoracic inlet angle, and cervical lordosis (C2–C7 angle). The DCS group was compared with a control group of 45 asymptomatic age- and sex-matched adults to the DCS group, who were studied in a recently published study. Results. Of our initial group of 767 patients, 45 with anterolisthesis (5.8%) were included for this study. The T1 slope was significantly greater for DCS (26.06° ± 7.3°) compared with the control group (22.32° ± 7.0°). No significant difference of the neck tilt, thoracic inlet angle, and C2–C7 angle was seen between the DSC group and the control group. Therefore, the T1 slope of the DSC group was significantly greater than that of the control group (P < 0.005). Conclusion. The DCS group was characterized by a greater T1 slope than the control group; therefore, we suggest that a high T1 slope may be a predisposing factor in developing DCS. Level of Evidence: 3

To investigate the effect of different pillow heights on the slope of the cervicothoracic spine segments. A prospective analysis of data from 16 asymptomatic adults (aged 20 to 30 years) was carried out. Exclusion criteria were history of injury or accident to the cervicothoracic spine, cervicothoracic spine surgery, or treatment for neck symptoms. We used three different pillow heights: flat (0 cm), 10-cm, and 20-cm pillows. Cervical sagittal parameters, measured with radiography, included; C2-7 Cobb's angle, T1 slope (T1S), thoracic inlet angle (TIA), and neck tilt (NT). Statistical analyses were performed using Spearman correlation coefficients. As the height of the pillow increased, the T1S & C2-7 Cobb's angle increased while the NT values tended to decrease. The TIA values, however, remained constant. Additionally, there was a statistically significant sex difference in T1S with the 0-cm pillow (p=0.01), and in NT with the 20-cm pillow (p=0.01). From the data obtained in this study, we recommend that the most suitable pillow height is 10 cm, considering the normal cervical lordosis.