Three-dimensional transient motion characteristics of atlanto-axial joint in healthy adults under physiological load / 中国组织工程研究

ABSTRACT

BACKGROUND:The cervical spine of the human body is an important structure carrying the head and connecting the spine. Its volume is smal, but its flexibility was great. Activity frequency was highest. Simultaneously, cervical spine is the most complicated bony structure of geometric and kinematic characteristics of human body, bears the physiological load of the head, has functions of flexion and extension, lateral bending and rotation. Therefore, the cervical spine has become one of the most vulnerable structures with degenerative diseases of the spine. Analysis of upper cervical spine biomechanics, recognition and understanding of its normal function and mechanical mechanism wil provide a theoretical basis for better treatment of upper cervical spine disorders. OBJECTIVE:To observe thein vivothree-dimensional kinematics of the upper cervical spine in healthy human beings under physiological load with dual fluorescence X-ray imaging system and spiral CT. METHODS:Seventeen healthy volunteers were recruited for this study. The vertebral segment motion of each subject was reconstructed with three-dimensional computed tomography and solid modeling software.In vivo cervical vertebral motion during functional postures was observed with dual fluoroscopic imaging. Coordinate systems were established at the vertebral center to obtain the intervertebral range of motion. RESULTS AND CONCLUSION: (1) During the flexion-extension motion, significant differences in the distance in coronal axis, sagittal axis and angle of rotation were detected in C1-2 and C2-3segments. (2) During the left-right bending motion, the angle of rotation was obviously greater at C1-2 segment than that at C2-3segment. During the left-right twisting motion, significant differences in distance of the vertical axis and the coronal axis, lateral flexion angle and rotation angle were detectable between C1-2and C2-3 segments. (3) These findings confirmed that dual fluorescence X-ray imaging system combined with CT scan can obtain atlanto-axial three-dimensional instantaneous motion of six-DOF data of healthy adults, and found that the main motion of the C1-2 vertebrae is rotating. These data may provide us with some new information about the in vivo kinematics of the upper cervical spine and the non-fixed surgical operation.