Abstract Background context Previous studies have reported position-dependent changes of the lumbar intervertebral foramen (LIVF) dimensions at different static flexion-extension postures. However, ...the changes of the LIVF dimensions during dynamic body motion have not been reported. Purpose The objective of this study was to investigate the in vivo dimensions of the LIVF during a dynamic weight-lifting activity. Study design/Setting This was a retrospective study. Methods Ten asymptomatic subjects were recruited for this study. Three-dimensional (3D) vertebral models of the lumbar segments from L2 to S1 were constructed for each subject using magnetic resonance images. The lumbar spine was then imaged using a dual fluoroscopic imaging system as the subject performed a dynamic weight-lifting activity from an upper body position of 45° to a maximal extension position. The in vivo positions of the vertebrae along the motion path were reproduced using the 3D vertebral models and the fluoroscopic images. The minimal area, height, and width of each LIVF during the dynamic body motion were analyzed. Results The LIVF area and width monotonically decreased with lumbar extension at all levels except L5–S1 (p<.05). On average, the LIVF area decreased by 7.4±6.7%, 10.8±7.7%, and 10.0±8.0% at the L2–L3, L3–L4, and L4–L5 levels, respectively, from the flexion to the upright standing position, and by 6.4±5.0%, 7.7±7.4%, and 5.1±5.1%, respectively, from the upright standing to the extension position. The LIVF height remained relatively constant at all segments during the dynamic activity. The foramen area, height, and width of the L5–S1 remained relatively constant throughout the activity. Conclusions Human lumbar foramen dimensions show segment-dependent characteristics during the dynamic weight-lifting activity.
Abstract Background context Neuroforaminal stenosis is one of the key factors causing clinical symptoms in patients with cervical radiculopathy. Previous quantitative studies on the neuroforaminal ...dimensions have focused on measurements in a static position. Little is known about dimensional changes of the neuroforamen in the cervical spine during functional dynamic neck motion under physiological loading conditions. Purpose To investigate the in vivo dimensional changes of the neuroforamen in human cervical spine (C3-C7) during dynamic flexion-extension neck motion. Study design A case-control study. Methods 10 asymptomatic subjects were recruited for this study. The cervical spine of each subject underwent magnetic resonance image (MRI) scanning for construction of three dimensional (3D) vertebrae models from C3 to C7. The cervical spine was then imaged using a dual fluoroscopic system while the subject performed a dynamic flexion-extension neck motion in a sitting position. The 3D vertebral models and the fluoroscopic images were used to reproduce the in vivo vertebral motion. The dimensions (area, height and width) were measured for each cervical neuroforamen (C3/C4, C4/C5, C5/C6 and C6/C7) in the following functional positons: neutral positon, maximal flexion and maximal extension. Repeated measures ANOVA and post-hoc analysis were used to examine the differences between levels and positions. Results Compared with the neutral position, almost all dimensional parameters (area, height and width) of the sub-axial cervical neuroforamen decreased in extension and increased in flexion, except the neuroforaminal area at C5/C6 ( P =0.07) and the neuroforaminal height at C6/C7 ( P =0.05) remained relatively constant from neutral to extension. When comparisons of the overall change from extension to flexion were made between segments, the overall changes of the neuroforaminal area and height revealed no significant differences between segments, the width overall change of the upper levels (C3/C4 and C4/C5) was significantly greater than the lower levels (C5/C6 and C6/C7) ( P <0.01). Conclusions The dimensional changes of the cervical neuroforamen showed segment-dependent characteristics during the dynamic flexion-extension. These data may have implications for diagnosis and treatment of patients with cervical radiculopathy.
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