J Korean Neurosurg Soc.  2013 Jun;53(6):356-359. 10.3340/jkns.2013.53.6.356.

T1 Slope and Cervical Sagittal Alignment on Cervical CT Radiographs of Asymptomatic Persons

• Park JH
• Cho CB
• Song JH
• Kim SW
• Ha Y
• Oh JK

• KMID: 2190823
• DOI: http://doi.org/10.3340/jkns.2013.53.6.356

Abstract

OBJECTIVE
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.
METHODS
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.
RESULTS
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.
CONCLUSION
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.

Keyword

T1 slope; Cervical sagittal alignment; Cobb's angle C2-7

MeSH Terms

Ambulatory Care Facilities
Axis, Cervical Vertebra
Bays
Congenital Abnormalities
Humans
Medical Records
Neck
Prejudice
Retrospective Studies
Spine

Figure

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  Fig. 1 A : T1 slope : the angle between a horizontal line and the upper end plate of T1. B : Neck tilt : the angle formed by a vertical line of sternum tip and the line drawn in the center of upper end plate. C : Cobb's angle C2-7 : the angel between the horizontal line of C2 lower end plate and the horizontal line of C7 lower end plate. D : SVA C2-7 : the distance between the plumb line of C2 dens tip and the plumb line of the center of C7 upper end plate. SVA : sagittal vertical axis.

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  Fig. 2 The sum of thoracic inlet outlet angle is the angle of T1 slope and neck tilt.

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  Fig. 3 The relationship between age and neck tilt, TIA. TIA : thoracic inlet angle.

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  Fig. 4 As increasing T1 slope (A), the Cobb's angle C2-7 (B) is getting higher. Consecutively, SVA C2-7 is getting lower and closer to the center of one's body. It shows C2 plumb line moves from anterior to posterior comparing to fixed C7 plumb line (C). SVA : sagittal vertical axis.

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