RESUMO
OBJECTIVE@#To determine whether C7 angles (C7 slope, C7S) could replace T1 angles (T1 slope, T1S) by correlation analysis of T1S and C7S.@*METHODS@#A total of 442 patients from July 2015 to July 2020 in outpatient and inpatient department were enrolled retrospectively, and 259 patients who could identify the upper endplate of T1 were screened out . Of them, there were 145 males and 114 females, aged from 20 to 83 years old with an average of (58.6±11.2) years, including 163 patients with cervical spine surgery and 96 non-surgical patients. Patients were stratified by sex, age, cervical kyphosis, cervical alignment imbalance, and cervical spine surgery. These 259 patients included 145 cases in the male group, 114 cases in the female group;76 cases in the youth group (<40 years old), 109 cases in the middle-aged group (40 to 60 years old), and 74 cases in the elderly group(>60 years old); 92 cases in the cervical kyphosis group, 167 cases in the non-kyphosis group;51 cases in the cervical sequence imbalance group, 208 cases in the non-imbalance group;163 cases in the cervical surgery group, 96 cases in the non-operation group. The correlations of C7S and T1S in various modalities groups were analyzed.@*RESULTS@#Of 442 patients, the recognition rate of upper endplate of T1 was 58.6%(259/442), and that of C7 was 90.7%. The mean T1S and C7S of the 259 patients were (24.5±8.0)° [(25.9±7.7)° in the male group and (23.7±6.9)° in the female group] and (20.8±7.3)° [(22.5±7.5)° in the male group and(19.7±5.8)° in the female group], respectively. The total correlation coefficient between C7S and T1S was r=0.89, R2=0.79, and the linear regression equation was T1S=0.91×C7S+4.35. In the above general information and the grouping of deformity factors, T1S was highly correlated with C7S(r value 0.85 to 0.92, P<0.05).@*CONCLUSION@#There is a high correlation between T1S and C7S in different factor groups. For cases where T1S cannot be measured, C7S can be used to provide guidance and reference for evaluating the sagittal balance of the spine, analyzing the condition, and formulating surgical plans.