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Published on: December 14, 2011
Effects of Parameter Combinations in Cervical Rotation-Traction Manipulation on Intervertebral Foramen Opening and
Hanze Mao1, Xinyu Wang2, Guangqi Lu1
1Second Department of Spine, Wangjing Hospital of China Academy of Chinese Medical Sciences, Beijing, People's Republic of China.
Background:
To investigate, using a finite element model, the effects of different combinations of rotation, flexion, and re-rotation parameters in cervical rotation-traction manipulation (CRTM) on intervertebral foramen opening and biomechanical distribution, and to provide a basis for segment-specific parameter optimization.
Methods:
A validated C2-T1 finite element model, derived from CT images of a healthy adult male volunteer, simulated CRTM by sequentially applying rotation, flexion, re-rotation, and upward traction. Rotation angles: 60°, 65°, 70°, 75°; flexion: 20°, 30°, 40°; re-rotation: 5°, 10°, 15°, with rotation+re-rotation sum ≤80°, yielding 27 combinations. Vertical diameter changes at C3/4-C7/T1 were measured, and stresses in vertebrae, discs, and facet cartilage were analyzed via stress cloud maps.
Results:
Foraminal opening showed segment-specific characteristics; increased flexion promoted opening, with flexion 40°being most effective. Optimal combinations were: C3/4 with axial rotation of 70°, re-rotation of 10°, and flexion of 40° (AR70-10_FL40); C4/5 with AR65-15_FL40; C5/6 with AR60-15_FL40; and C6/7 and C7/T1 with AR60-10_FL40. Peak vertebral stress generally corresponded to the segments showing maximal foraminal opening. Stress trends in the vertebral bodies, discs, and facet articular cartilage were consistent, following the order AR60-10_FL40 < AR65-15_FL40 < AR60-15_FL40 < AR70-10_FL40. High-stress regions were mainly located in the upper and middle cervical spine, with differences reflected primarily in stress magnitude rather than stress location.
Conclusion:
CRTM effects appear parameter-dependent and segment-specific. Flexion may be key in promoting opening, with segment-specific responses to rotation/re-rotation. Parameter adjustments affect both opening and stress distribution, suggesting segmental controllability. However, as these findings derive solely from a finite element model, they are preliminary biomechanical evidence, not directly applicable clinically. Further clinical and cadaveric studies are warranted.
