Inter- and intra-observer reliability of the Cobb angle in the measurement of vertebral, local and segmental kyphosis of traumatic lumbar spine fractures in the lateral X-ray.
BACKGROUND
Measurement of the vertebral, local and segmental kyphosis according to Cobb is a standard procedure in the assessment of traumatic, idiopathic and degenerative spinal deformities. The purpose of this study was to evaluate the inter- and intra-observer reliability of these three radiological angles on the basis of lateral X-rays in lumbar spine fractures with spinal kyphosis.


METHODS
A consecutive series of 88 patients with traumatic lumbar spine fractures with kyphotic deformities were included in the study. All patients were younger that 50 years of age and had an adequate trauma leading to the fracture. Three independent observers with different levels of clinical training measured the vertebral, segmental and local kyphosis of these patients on the basis of lateral X-rays. The readings were repeated 4 weeks later to assess intra-observer reliability.


RESULTS
The most common injury mechanism was a fall from a height of more than 3 m. The first lumbar vertebra was the most commonly affected. Mean inter- and intra-observer reliabilities were good for the vertebral (mean ICC: 0.6607; mean ICC: 0.6979) and local (mean ICC: 0.7778; mean ICC: 0.7642) kyphosis and excellent (mean ICC: 0.8129; mean ICC: 0.8103) for the segmental kyphosis.


CONCLUSIONS
In this study, the segmental-, vertebral-, and local kyphosis angle according to Cobb showed sufficient inter- and intra-observer reliability for the use in daily practice and scientific studies.
Ulmar
Benjamin
B
Section Spine Surgery, BG Trauma Center, Department of Trauma and Reconstructive Surgery, Eberhard-Karls-University Tübingen, Schnarrenbergstrasse 95, 72076, Tübingen, Germany.
Gühring
Markus
M
Schmälzle
Traude
T
Weise
Kuno
K
Badke
Andreas
A
Brunner
Alexander
A
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging*; D008159:Lumbar Vertebrae / Q000293:injuries*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011859:Radiography; D016103:Spinal Fractures / Q000150:complications*