Berry DB, Rodríguez-Soto AE, Tokunaga JR, Gombatto SP, Ward SR.
Vertebral level-dependent, angular, and linear translations of the spine have
been measured in 2D and 3D using several imaging methods to quantify postural
changes due to loading conditions and tasks. Here, we propose and validate a
semiautomated method for measuring lumbar intervertebral angles and translations
from upright MRI images using an endplate-based, joint coordinate system (JCS).
This method was validated using 3D printed structures, representing
intervertebral discs (IVD) at predetermined angles and heights, which were
positioned between adjacent cadaveric vertebrae as a gold standard. Excellent
agreement between our measurements and the gold standard was found for
intervertebral angles in all anatomical planes (ICC > .997) and intervertebral
distance measurements (ICC > .949). The proposed endplate-based JCS was compared
with the vertebral body-based JCS proposed by the International Society of
Biomechanics (ISB) using the 3D printed structures placed between 3 adjacent
vertebrae from a cadaver with scoliosis. The endplate-based method was found to
have better agreement with angles in the sagittal plane (ICC = 0.985) compared
with the vertebral body-based method (ICC = .280). Thus, this method is accurate
for measuring 3D intervertebral angles in the healthy and diseased lumbar spine.
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