In vitro biomechanical characteristics of the effect of Rotation-Traction Manipulation on lower cervical vertebral displacement
Feng Minshan1, 2, Han Changxiao1, 2, Liang Dongzhu3, Zhao Weidong3, Yin Xunlu1, 2, Liu Guangwei1, 2, Zhu Liguo1, 2
1Wangjing Hospital of China Academy of Chinese Medical Sciences, Beijing 100102, China; 2Beijing Key Laboratory of TCM Bone Setting, Beijing 100102, China; 3Southern Medical University, Guangzhou 510515, Guangdong Province, China
Abstract: BACKGROUND: It is helpful to evaluate vertebral displacement for revealing the manipulative biomechanical mechanisms. However, there is, at present, no study to analyze the vertebral displacement of Rotation-Traction Manipulation.
OBJECTIVE: To observe the displacement of the lower cervical vertebrae during Rotation-Traction Manipulation and the effect of different thrust forces on the vertebral displacement.
METHODS: Seven healthy adult male cervical spine specimens were selected and the pre-traction and different thrust forces (50, 150, 250 N) were simulated on the specimens by using the MTS machine and fixture. The kinematic measurements of different positions of C4-C7 vertebrae (right transverse process, vertebral body midpoint, left transverse process) were performed by using the motion capture system to determine vertebral body displacement under pre-traction and different thrust forces.
RESULTS AND CONCLUSION: (1) During pre-traction, the longitudinal displacement of the right transverse process and midpoint of the vertebral gradually decreased from C4 to C7 (P < 0.05), and the longitudinal displacement of the right transverse process of C4 was significantly greater than that of the left transverse process (P < 0.05). (2) During thrust, the longitudinal displacement of the right transverse process and midpoint of the vertebral gradually decreased from C4 to C7 (P < 0.05), and the longitudinal displacement of the right transverse process of C4 was significantly greater than that of the left transverse process for 150 N and 250 N thrust forces (P < 0.05). (3) Comparison of different thrust forces: The longitudinal displacement of each segment and position of the vertebral body in the 50 N group was significantly smaller than that in the 150 N and 250 N groups (P < 0.05). The differences in longitudinal displacement of each segment and position of the vertebral body between the 150 N and 250 N groups were not statistically significant (P > 0.05). (4) The results show that the Rotation-Traction Manipulation can adjust the lower cervical vertebrae displacement, with the largest displacement of the C4 transverse process on the rotational side, and positive displacement with increasing thrust force.
Key words: Rotation-Traction Manipulation, lower cervical vertebra, vertebral displacement, biomechanics, motion capture