Kinematics of the Cervical Spine in Lateral Bending

Ishii, Takahiro; Mukai, Yoshihiro; Hosono, Noboru; Sakaura, Hironobu; Fujii, Ryutaro; Nakajima, Yoshikazu; Tamura, Shinichi; Iwasaki, Motoki; Yoshikawa, Hideki; Sugamoto, Kazuomi

doi:10.1097/01.brs.0000195173.47334.1f

Cited by 136 publications

(90 citation statements)

References 17 publications

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“…17 The moments were chosen within the in vivo physiological range: flexion (45°)/extension (35°), [7][8][9]14,25,29,37,49 axial rotation on each side (20°), 20,28,38 and lateral bending on each side (25°). 21,37 Next, these moment loads in 3 planes were applied to the C-3 vertebra under a compressive preload of 73.6 N.…”

Section: Methodsmentioning

confidence: 99%

Relationship between biomechanical changes at adjacent segments and number of fused bone grafts in multilevel cervical fusions: a finite element investigation

Hussain

Nassr

Natarajan

et al. 2014

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Object Biomechanical studies have shown that anterior cervical fusion construct stiffness and arthrodesis rates vary with different reconstruction techniques; however, the behavior of the adjacent segments in the setting of different procedures is poorly understood. This study was designed to investigate the adjacent-segment biomechanics after 3 different anterior cervical decompression and fusion techniques, including 3-level discectomy and fusion, 2-level corpectomy and fusion, and a corpectomy-discectomy hybrid technique. The authors hypothesized that biomechanical changes at the segments immediately superior and inferior to the multilevel fusion would be inversely proportional to the number of fused bone grafts and that these changes would be related to the type of fusion technique. Methods A previously validated 3D finite element model of an intact C3–T1 segment was used. Three C4–7 fusion models were built from this intact model by varying the number of bone grafts used to span the decompression: a 1-graft model (2-level corpectomy), a 2-graft model (C-5 corpectomy and C6–7 discectomy), and a 3-graft model (3-level discectomy). The corpectomy and discectomy models were also previously validated and compared well with the literature findings. Range of motion, disc stresses, and posterior facet loads at the segments superior (C3–4) and inferior (C7–T1) to the fusion construct were assessed. Results Motion, disc stresses, and posterior facet loads generally increased at both of the adjacent segments in relation to the intact model. Greater biomechanical changes were noted in the superior C3–4 segment than in the inferior C7–T1 segment. Increasing the number of bone grafts from 1 to 2 and from 2 to 3 was associated with a lower magnitude of biomechanical changes at the adjacent segments. Conclusions At segments adjacent to the fusion level, biomechanical changes are not limited solely to the discs, but also propagate to the posterior facets. These changes in discs and posterior facets were found to be lower for discectomy than for corpectomy, thereby supporting the current study hypothesis of inverse relationship between the adjacent-segment variations and the number of fused bone grafts. Such changes may go on to influence the likelihood of adjacent-segment degeneration accordingly. Further studies are warranted to identify the causes and true impact of these observed changes.

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Section: Methodsmentioning

confidence: 99%

Relationship between biomechanical changes at adjacent segments and number of fused bone grafts in multilevel cervical fusions: a finite element investigation

Hussain

Nassr

Natarajan

et al. 2014

SPI

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“…To analyze in vivo 3D kinematics more accurately, we developed a novel 3D motion analysis system using 3D magnetic resonance imaging (MRI). Our colleagues have already reported in vivo 3D kinematics of the cervical spine and wrist joint using this original method [1][2][3][4]. In addition to these studies, in vivo 3D intervertebral motions of the normal lumbar spine in various trunk motions have also been under investigation.…”

Section: Introductionmentioning

confidence: 99%

“…Kinematic variables were measured by automatically superimposing segmented 3D MRI of the vertebrae in the neutral position over images for each position using this method of registration [1][2][3][4]. The correlation coefficient was used as a method of measuring similarity of voxel values for registration.…”

Section: Volume Registrationmentioning

confidence: 99%

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Kinematics of the lumbar spine in trunk rotation: in vivo three-dimensional analysis using magnetic resonance imaging

et al. 2007

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In vivo three-dimensional (3D) kinematics of the lumbar spine has not been well evaluated by the conventional methods because of their methodological limitations, while 3D intervertebral motions have been quantitatively determined by cadaver studies. We thus developed a novel 3D analyzing system for the relative motions of individual vertebrae using 3D magnetic resonance imaging (MRI) and analyzed in vivo 3D intervertebral motions of the lumbar spine during trunk rotation. Ten healthy volunteers underwent 3D MRI of the lumbar spine in nine positions with 15°increments during trunk rotation (0°, 15°, 30°, 45°, and maximum). Relative motions of the lumbar spine were calculated by automatically superimposing a segmented 3D MRI of the vertebra in the neutral position over images of each position using the voxelbased registration method. These 3D motions were represented with 6 degrees of freedom by Euler angles and translations on the coordinate system. The mean axial rotation of ten healthy volunteers of each lumbar spinal segment in 45°trunk rotation to each side ranged from 1.2°t o 1.7°. Coupled flexion with axial rotation was observed at the segments from L1/2 to L5/S1. Coupled lateral bending of the segments from L1/2 to L4/5 was in the opposite direction of the trunk rotation, while that of T12/L1 and L5/S1 was in the same direction. The direction of the coupled lateral bending in the present study was different from that in the previous cadaver study only at L4/5. This difference might result from the non-load state of the supine position in the current study and/or the non-physiological state in the cadaver study. Our system has two limitations: (1) the study was conducted with each volunteer in the supine position, and (2) because the rotation device regulated trunk rotation, trunk rotation might not have been physiological. In vivo 3D intervertebral motions of the lumbar spine during trunk rotation were evaluated using our novel motion analysis system. These data may be useful for the optimal orthopaedic management of lumbar spinal disorders.

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“…processes [3,13,16,23,33,35,37,39,51,58]. Degenerative disc disease in the cervical spine can cause abnormal motions and altered load distribution within the disc, leading to discogenic pain and severely limiting the ability of individuals to perform ADL.…”

mentioning

confidence: 99%

Primary and coupled motions after cervical total disc replacement using a compressible six-degree-of-freedom prosthesis

et al. 2010

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This study tested the hypotheses that (1) cervical total disc replacement with a compressible, sixdegree-of-freedom prosthesis would allow restoration of physiologic range and quality of motion, and (2) the kinematic response would not be adversely affected by variability in prosthesis position in the sagittal plane. Twelve human cadaveric cervical spines were tested. Prostheses were implanted at C5-C6. Range of motion (ROM) was measured in flexion-extension, lateral bending, and axial rotation under ±1.5 Nm moments. Motion coupling between axial rotation and lateral bending was calculated. Stiffness in the high flexibility zone was evaluated in all three testing modes, while the center of rotation (COR) was calculated using digital video fluoroscopic images in flexion-extension. Implantation in the middle position increased ROM in flexion-extension from 13.5 ± 2.3 to 15.7 ± 3.0°(p \ 0.05), decreased axial rotation from 9.9 ± 1.7 to 8.3 ± 1.6°(p \ 0.05), and decreased lateral bending from 8.0 ± 2.1 to 4.5 ± 1.1°( p \ 0.05). Coupled lateral bending decreased from 0.62 ± 0.16 to 0.39 ± 0.15°for each degree of axial rotation (p \ 0.05). Flexion-extension stiffness of the reconstructed segment with the prosthesis in the middle position did not deviate significantly from intact controls, whereas the lateral bending and axial rotation stiffness values were significantly larger than intact. Implanting the prosthesis in the posterior position as compared to the middle position did not significantly affect the ROM, motion coupling, or stiffness of the reconstructed segment; however, the COR location better approximated intact controls with the prosthesis midline located within ±1 mm of the disc-space midline. Overall, the kinematic response after reconstruction with the compressible, six-degree-offreedom prosthesis within ±1 mm of the disc-space midline approximated the intact response in flexion-extension. Clinical studies are needed to understand and interpret the effects of limited restoration of lateral bending and axial rotation motions and motion coupling on clinical outcome.

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Kinematics of the Cervical Spine in Lateral Bending

Abstract: We succeeded in identifying in vivo coupled motions of the cervical spine in lateral bending for the first time.

Cited by 136 publications

References 17 publications

Relationship between biomechanical changes at adjacent segments and number of fused bone grafts in multilevel cervical fusions: a finite element investigation

Relationship between biomechanical changes at adjacent segments and number of fused bone grafts in multilevel cervical fusions: a finite element investigation

Kinematics of the lumbar spine in trunk rotation: in vivo three-dimensional analysis using magnetic resonance imaging

Primary and coupled motions after cervical total disc replacement using a compressible six-degree-of-freedom prosthesis

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