Measurement of occipitocervical angle.
METHODS
This study compared the reliability of 3 techniques used to measure alignment between the occiput and cervical spine.


OBJECTIVE
Intraobserver and interobserver intraclass correlation coefficient were computed to determine the most reliable method to measure occipitocervical angle.


BACKGROUND
No studies have been performed comparing occipitocervical angle measurement techniques.


METHODS
The angles between the inferior endplate of second cervical vertebrae and the occiput line using the Chamberlain line, McRae line, and McGregor line were measured from lateral cervical radiographs of 30 healthy volunteers. Five spine surgeons made measurements.


RESULTS
Mean intraobserver variances of the angles using Chamberlain line, McRae line, and McGregor line were 2.0 degrees (ranging from 0 degrees-15 degrees), 4.7 degrees (from 0 degrees-28 degrees), and 1.5 degrees (from 0 degrees-9 degrees), respectively; intraobserver intraclass correlation coefficients of the angles were 0.956, 0.835, and 0.975. Mean interobserver variances of the angles using Chamberlain line, McRae line, and McGregor line were 2.3 degrees (from 0.4 degrees-6.4 degrees), 5.0 degrees (from 1.8 degrees-11.9 degrees), and 1.4 degrees (from 0 degrees-4.5 degrees), respectively; interobserver intraclass correlation coefficients were 0.939, 0.802, and 0.972. The highest reliability indexes were obtained for McGregor line.


CONCLUSIONS
The McGregor line is the most reproducible and reliable method for measurement of the occipitocervical angle.
Shoda
Naoki
N
Departments of Orthopaedic Surgery, The University of Tokyo, Tokyo, Japan. tkyort-office@umin.ac.jp
Takeshita
Katsushi
K
Seichi
Atsushi
A
Akune
Toru
T
Nakajima
Susumu
S
Anamizu
Yorito
Y
Miyashita
Mitsunori
M
Nakamura
Kozo
K
D000886:Anthropometry / Q000379:methods*; D001368:Axis, Cervical Vertebra / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D002508:Cephalometry / Q000379:methods*; D006801:Humans; D009333:Neck / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D015588:Observer Variation; D009777:Occipital Bone / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D021362:Palate, Hard / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D011859:Radiography; D012016:Reference Values; D015203:Reproducibility of Results