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DOS Kongressen 2016 ·
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The effect of spinal rotation on Cobb’ angle
Christian Wong, Johanna Hall, Kasper Gosvig
Department of Othopedics, University hospital of Hvidovre; Department
of Radiology, University hospital of Hvidovre; Department of Othopedics,
University hospital of Hvidovre
Background:
The importance of vertebral rotation as well as measurement of
vertebral rotation in the development and management of scoliosis is recog-
nized as important. The common radiological method of evaluating scoliosis by
Cobb’s angle is biased by measurement variation
Purpose / Aim of Study:
To examine the effect of vertebral axial rotation on
Cobb’s angle as an indicator of the potential and inherent bias of truncal rotation
in the normal or slight scoliotic spine
Materials and Methods:
This study was conducted as a cross-sectional study,
where 40 anonymized patients were included and scanned by CT consecutively.
Coronal reconstructions covering the whole pelvis and spine executed in an an-
gle of -15, -10, -5, 0 ,5,10 and 15 degrees (dg). Cobb’s angle was meas-
ured from TH4-TH11 in the thoracic part and TH12-L4 for the lumbar part.
All measurements were performed blinded by three experienced doctors sepa-
rately. The data were evaluated by mixed effect model, including fixed effects
for reconstructions and parts and a random slope effect for reconstructions
within each patient. all analysis was perform in SPSS (ver 22)
Findings / Results:
Measurements of Cobbs angle ranged from 0.05 dg to
36.3 dg with at average of 5.5 dg for the thoracic spine and from 0.3 dg to 29.1
dg with an average of 3.8 dg in the lumbar spine. There was a significant effect
for vertebral rotation (< 0.001) with an estimated effect of 4.2 dg for every 5
dg vertebral rotation (SE = 0.6 dg)
Conclusions:
Vertebral rotation has a significant effect on Cobb’s angle. This
indicates, that there seem to be a clinical implication, where truncal rotation un-
der radiological examination bias Cobb’s angle in the slightly scoliosis and normal
spine, thus causing potential misdiagnosis of scoliosis (> 10 degrees of Cobb’s
angle) and initiation of monitoring and management of early scoliosis
No conflicts of interest reported
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