Abstract
Study Design We present a patient-specific computer model created to translate two-dimensional
(2D) fluoroscopic motion data into three-dimensional (3D) in vivo biomechanical motion
data.
Objective The aim of this study is to determine the in vivo biomechanical differences in patients
with and without acute low back pain. Current dynamic imaging of the lumbar spine
consists of flexion–extension static radiographs, which lack sensitivity to out-of-plane
motion and provide incomplete information on the overall spinal motion. Using a novel
technique, in-plane and coupled out-of-plane rotational motions are quantified in
the lumbar spine.
Methods A total of 30 participants—10 healthy asymptomatic subjects, 10 patients with low
back pain without spondylosis radiologically, and 10 patients with low back pain with
radiological spondylosis—underwent dynamic fluoroscopy with a 3D-to-2D image registration
technique to create a 3D, patient-specific bone model to analyze in vivo kinematics
using the maximal absolute rotational magnitude and the path of rotation.
Results Average overall in-plane rotations (L1–L5) in patients with low back pain were less
than those asymptomatic, with the dominant loss of motion during extension. Those
with low back pain also had significantly greater out-of-plane rotations, with 5.5
degrees (without spondylosis) and 7.1 degrees (with spondylosis) more out-of-plane
rotational motion per level compared with asymptomatic subjects.
Conclusions Subjects with low back pain exhibited greater out-of-plane intersegmental motion
in their lumbar spine than healthy asymptomatic subjects. Conventional flexion–extension
radiographs are inadequate for evaluating motion patterns of lumbar strain, and assessment
of 3D in vivo spinal motion may elucidate the association of abnormal vertebral motions
and clinically significant low back pain.
Keywords
low back pain - lumbar strain - spondylosis - biomechanics - kinematics
