The Studies Of Anatomic Biomechanics And Clinical Treatment On The Surgical Disorders Of The Upper Cervical Spine

ObjectivesThe surgical disorders of the upper cervical spine are common and difficult to treat in the clinic. The purposes of this thesis are: (1) To report the anatomic parameters and the anti-stretch property of transverse ligament of atlas, (2) To set up the models of atlas and axis and to evaluate the mechanisms of their fractures based on the models, (3) To evaluate the stability of the CO-1 and Cl-2 through measuring the three-dimensional range of motion (ROM), (4) To study the feasibility of posterior screw fixation on the lateral mass of atlas in the aspects of anatomy and biomechanics, (5) To offer the clinical classification of the atlanto-axial dislocation according to their clinic characteristics, and to summarize the clinical experience of surgical treatment on the upper cervical disorders.Materials and Methods1. Twenty-four Formalin marinated and nine fresh adult craniocervical specimens were used. The anatomic characters of the transverse ligament of atlas were observed and the anatomic parameters, the length, thickness and the width in center and the widths in both sides were measured. Two of the nine fresh transverse ligament specimens were observed hi histology, and seven of them were used to test the anti-stretch property on the MTS -858(USA).2. Twelve fresh adult craniocervical specimens were randomly divided equally into two groups. Each specimen served as its own control and was tested in the following sequence: A-intact, B-fracture of bilateral posterior arch of atlas, C-fracture of bilateral posterior arch and unilateral anterior arch of atlas, D-fracture of bilateral posterior arch and anterior arch of atlas (Jefferson's fracture) in the first group and A-intact, E-fracture of unilaterallateral mass of atlas, F-fracture of unilateral lateral mass and ipsilateral anterior arch of atlas in the second group. The ROMs of CO-1 and Cl-2 motive segments were measured. With the ROMs of intact and injured specimens were compared each other, the stability of craniocervical junction after various fracture of atlas was analyzed.3. One intact fresh adult cadaveric atlas and axis were scanned by CT with 1mm interval. The picture files of CT were transferred to PC and by them the three-dimensional coordinates were gotten. These information were utilized to establish the stereoscopic models of atlas and axis through the software of PRO/E. Then the models were transmitted to the program of Mentas, through which material property was yielded and element was compartmentalized. According to the clinical characteristic of atlas fracture and odontoid fracture and Hangman fracture, various boundary conditions and loads were endowed. The theoretical stress distributing values were calculated, and which were compared with prefigured results to analyze the mechanisms of atlas fractures, odontoid fractures and Hangman fracture.4. 30 atlas specimens of native adults were used to measure the significant clinic data. 6 fresh specimens of upper cervical were used to observe the relationship of C2 nerve and the lateral mass of atlas. The pull-out force of screw on the lateral mass of Atlas was measured and compared with that of screw on the occiptal and axial pedicle screw respectively. The ROM of upper cervical spine after posterior screw fixation in the lateral mass was measured and compared with that of pre-fixation and normal control.5. The design and clinical application of bivector traction bed, the classification and its treatment of chronic atlanto-axial dislocation, the treatment of odontoid fractures with anterior screw fixation, the posterior occipitocervical fixation with occipitocervical CD-rod system, and the complications on the upper cervical operations were summarized.Results1. The length of the transverse ligament was 20.0±2.4 (14.5~25.1) mm.The thickness and the width on the midpoint of the transverse ligament were 2.1±0.5 (1.2-3.1) mm and 10.7±1.6 (8.0-14.2) mm respectively. The relationship between transverse ligament and odontoid process could b...