TY - JOUR
T1 - Novel Angular Measures of Cervical Deformity Account for Upper Cervical Compensation and Sagittal Alignment
AU - Protopsaltis, Themistocles S.
AU - Lafage, Renaud
AU - Vira, Shaleen
AU - Sciubba, Daniel
AU - Soroceanu, Alex
AU - Hamilton, Kojo
AU - Smith, Justin
AU - Passias, Peter G.
AU - Mundis, Gregory
AU - Hart, Robert
AU - Schwab, Frank
AU - Klineberg, Eric
AU - Shaffrey, Christopher
AU - Lafage, Virginie
AU - Ames, Christopher
N1 - Publisher Copyright:
© 2017 Wolters Kluwer Health, Inc.
PY - 2017
Y1 - 2017
N2 - Study Design: This is a retrospective review of a prospective multicenter database. Objective: This study introduces 2 new cervical alignment measures accounting for both cervical deformity (CD) and upper cervical compensation. Summary of Background Data: Current descriptions of CD like the C2-C7 sagittal vertical axis (cSVA) do not account for compensatory mechanisms such as C0-C2 lordosis and pelvic tilt, which makes surgical planning difficult. The craniocervical angle (CCA) combines the slope of McGregor's line and the inclination from C7 to the hard palate. The C2-pelvic tilt (CPT) combines C2 tilt and pelvic tilt. Like the T1 pelvic angle, CPT is less affected by lower extremity and pelvic compensation. Methods: Novel and existing CD measures were correlated in 781 patients from a thoracolumbar deformity (TLD) database and 61 patients from a prospective CD database. CD patients were subanalyzed by region of deformity driver: Cervical or cervico-thoracic junction. TLD patients were substratified according to whether or not they had CD as well, where CD was defined as cSVA>4 cm or T1 slope minus cervical lordosis mismatch (TS-CL) >20. Results: TLD cohort: Mean cSVA was 31.7±17.8 mm. Subanalysis of TLD patients with CD versus no-CD demonstrated significant differences in CCA (56.2 vs. 60.6, P<0.001) and CPT (32.6 vs. 19.3, P<0.001). CCA and CPT correlated with cSVA (r=-0.488/r=0.418, P<0.001) and C0-C2 lordosis (r=-0.630/r=0.289,P<0.001). CD cohort: Mean cSVA was 47.3±32.2 mm. CCA and CPT correlated with cSVA (r=-0.811/r=0.657, P<0.001) and C0-C2 lordosis (r=-0.656/r=0.610, P<0.001). CD cohort subanalysis indicated that CT patients were significantly more deformed by cSVA (71.3 vs 24.0 mm, P<0.001), CCA (47.1 vs 59.1 degrees, P<0.001), and CPT (63.3 vs 43.8 degrees, P=0.002). Using linear regression analysis, cSVA of 4 cm corresponded to CCA of 53.2 degrees (r 2 =0.5) and CPT of 48.5 degrees (r 2 =0.4). Conclusions: CCA and CPT account for both cervical sagittal alignment and upper cervical compensation and can be utilized in assessment of cervical alignment.
AB - Study Design: This is a retrospective review of a prospective multicenter database. Objective: This study introduces 2 new cervical alignment measures accounting for both cervical deformity (CD) and upper cervical compensation. Summary of Background Data: Current descriptions of CD like the C2-C7 sagittal vertical axis (cSVA) do not account for compensatory mechanisms such as C0-C2 lordosis and pelvic tilt, which makes surgical planning difficult. The craniocervical angle (CCA) combines the slope of McGregor's line and the inclination from C7 to the hard palate. The C2-pelvic tilt (CPT) combines C2 tilt and pelvic tilt. Like the T1 pelvic angle, CPT is less affected by lower extremity and pelvic compensation. Methods: Novel and existing CD measures were correlated in 781 patients from a thoracolumbar deformity (TLD) database and 61 patients from a prospective CD database. CD patients were subanalyzed by region of deformity driver: Cervical or cervico-thoracic junction. TLD patients were substratified according to whether or not they had CD as well, where CD was defined as cSVA>4 cm or T1 slope minus cervical lordosis mismatch (TS-CL) >20. Results: TLD cohort: Mean cSVA was 31.7±17.8 mm. Subanalysis of TLD patients with CD versus no-CD demonstrated significant differences in CCA (56.2 vs. 60.6, P<0.001) and CPT (32.6 vs. 19.3, P<0.001). CCA and CPT correlated with cSVA (r=-0.488/r=0.418, P<0.001) and C0-C2 lordosis (r=-0.630/r=0.289,P<0.001). CD cohort: Mean cSVA was 47.3±32.2 mm. CCA and CPT correlated with cSVA (r=-0.811/r=0.657, P<0.001) and C0-C2 lordosis (r=-0.656/r=0.610, P<0.001). CD cohort subanalysis indicated that CT patients were significantly more deformed by cSVA (71.3 vs 24.0 mm, P<0.001), CCA (47.1 vs 59.1 degrees, P<0.001), and CPT (63.3 vs 43.8 degrees, P=0.002). Using linear regression analysis, cSVA of 4 cm corresponded to CCA of 53.2 degrees (r 2 =0.5) and CPT of 48.5 degrees (r 2 =0.4). Conclusions: CCA and CPT account for both cervical sagittal alignment and upper cervical compensation and can be utilized in assessment of cervical alignment.
KW - HRQOL
KW - Sagittal cervical deformity
KW - upper cervical compensation
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U2 - 10.1097/BSD.0000000000000554
DO - 10.1097/BSD.0000000000000554
M3 - Article
C2 - 28650879
AN - SCOPUS:85021290615
SN - 2380-0186
VL - 30
SP - E959-E967
JO - Clinical Spine Surgery
JF - Clinical Spine Surgery
IS - 7
ER -