Skip to main content
Journal cover image

A New Piece of the Puzzle to Understand Cervical Sagittal Alignment: Utilizing a Novel Angle δ to Describe the Relationship among T1 Vertebral Body Slope, Cervical Lordosis, and Cervical Sagittal Alignment.

Publication ,  Journal Article
Goldschmidt, E; Angriman, F; Agarwal, N; Trevisan, M; Zhou, J; Chen, K; Gerszten, PC; Kanter, AS; Okonkwo, DO; Passias, P; Scheer, J; Bess, S ...
Published in: Neurosurgery
March 1, 2020

Cervical alignment has become increasingly important in the planning of spine surgery. A relationship between the slope of T1 (T1S), the cervical lordosis (CL), and the overall cervical sagittal vertical axis (cSVA) has previously been demonstrated, but the exact nature of this relationship is poorly understood. In this study, we derive theoretical and empirical equations to better understand how T1S and CL affect cSVA. The first equation was developed on a theoretical basis using inherent trigonometric relationships of the cervical spine. By treating the cervical spine as the arc of a circumference, and by taking into account the cervical height (CH), the geometric relationship between theT1S, CL, and cSVA was described via a trigonometric identity utilizing a novel angle δ subtended by the CH and cSVA (δ = T1S-CL/2). The second equation was developed on an empiric basis by performing a multiple linear regression on data obtained from a retrospective review of a large multicenter deformity database. The theoretical equation determined that the value of cSVA could be expressed as: $cSVA\ = \ CH*{\rm{tan}}( {\pi /180*( {T1S - CL/2} )} )$. The empirical equation determined that value of cSVA could be expressed as: $cSVA=({1.1*T1} )\ - ( {0.43*CL} ) + 6.69$. In both, the sagittal alignment of the head over the shoulders is directly proportional to the T1S and inversely proportional to CL/2. These 2 equations may allow surgeons to better understand how the CL compensates for the T1S, to accurately predict the postoperative cSVA, and to customize cervical interbody grafts by taking into consideration each individual patient's specific cervical spine parameters.

Duke Scholars

Altmetric Attention Stats
Dimensions Citation Stats

Published In

Neurosurgery

DOI

EISSN

1524-4040

Publication Date

March 1, 2020

Volume

86

Issue

3

Start / End Page

446 / 451

Location

United States

Related Subject Headings

  • Thoracic Vertebrae
  • Scoliosis
  • Retrospective Studies
  • Radiography
  • Postural Balance
  • Neurology & Neurosurgery
  • Neck
  • Lordosis
  • Humans
  • Databases, Factual
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Goldschmidt, E., Angriman, F., Agarwal, N., Trevisan, M., Zhou, J., Chen, K., … International Spine Study Group (ISSG), . (2020). A New Piece of the Puzzle to Understand Cervical Sagittal Alignment: Utilizing a Novel Angle δ to Describe the Relationship among T1 Vertebral Body Slope, Cervical Lordosis, and Cervical Sagittal Alignment. Neurosurgery, 86(3), 446–451. https://doi.org/10.1093/neuros/nyz088
Goldschmidt, Ezequiel, Federico Angriman, Nitin Agarwal, Marcos Trevisan, James Zhou, Katherine Chen, Peter C. Gerszten, et al. “A New Piece of the Puzzle to Understand Cervical Sagittal Alignment: Utilizing a Novel Angle δ to Describe the Relationship among T1 Vertebral Body Slope, Cervical Lordosis, and Cervical Sagittal Alignment.Neurosurgery 86, no. 3 (March 1, 2020): 446–51. https://doi.org/10.1093/neuros/nyz088.
Goldschmidt E, Angriman F, Agarwal N, Trevisan M, Zhou J, Chen K, Gerszten PC, Kanter AS, Okonkwo DO, Passias P, Scheer J, Protopsaltis T, Lafage V, Lafage R, Schwab F, Bess S, Ames C, Smith JS, Shaffrey CI, Miller E, Jain A, Neuman B, Sciubba DM, Burton D, Hamilton DK, International Spine Study Group (ISSG). A New Piece of the Puzzle to Understand Cervical Sagittal Alignment: Utilizing a Novel Angle δ to Describe the Relationship among T1 Vertebral Body Slope, Cervical Lordosis, and Cervical Sagittal Alignment. Neurosurgery. 2020 Mar 1;86(3):446–451.
Journal cover image

Published In

Neurosurgery

DOI

EISSN

1524-4040

Publication Date

March 1, 2020

Volume

86

Issue

3

Start / End Page

446 / 451

Location

United States

Related Subject Headings

  • Thoracic Vertebrae
  • Scoliosis
  • Retrospective Studies
  • Radiography
  • Postural Balance
  • Neurology & Neurosurgery
  • Neck
  • Lordosis
  • Humans
  • Databases, Factual