Occipitocervical Fusion Angle And Lower Cervical Spine Degeneration In Patients With Craniocervical Junction Malformation

BACKGROUND:Cranial neck border area malformation is a common clinical disease, because the pillow neck the diversity of the structure and operation method of complex and become the focus of clinical research. Occipital cervical fusion is the main treatment of cranial neck border area deformity, its main purpose is to lift the compression of the spinal cord and maintain the stability of the pillow neck. But the occipital cervical fusion of the cervical spine is also more and more get the attention of the clinicians, the influence of these effects are mainly the cervical curvature change and degeneration. In this paper, in view of the congenital cranial neck deformity, and cause of the change of cervical vertebra occipital cervical fusion were analyzed. This paper adopted the S value, as a major indicator for the degeneration of the cervical spine, Because in patients without osteoporosis, the degeneration of cervical vertebra mainly presents in the intervertebral disk. The height of the vertebral body is constant basically. Thus, the ratio (S value) of the height of cervical disc and the height of cervical vertebra can be used to measure the degeneration of cervical vertebra. The small S value indicates severe degeneration of cervical vertebra.OBJECTIVE:To measure the lateral radiograph of cervical vertebra in patients with craniocervical malformation undergoing occipitocervical fusion, to analyze the relationship between occipitocervical fixed angle during fusion and lower cervical spine degeneration after fusion, and to identify an optimal angle of occipitocervical fusion.To the pillow cervical arthrodesis intraoperative pillow neck Angle fixed to provide the reference.METHODS:A total of41patients with craniocervical malformation undergoing occipitocervical fusion were included. The base of skull concave23cases,20cases Chiari malformation type,The sag of the skull base consolidation Chiari malformation10cases,8cases of atlanto-axial joint dislocation.According to the occipitocervical angle (Oc-C2angle) immediately after fusion, the patients with craniocervical malformation undergoing occipitocervical fusion were assigned to three groups:occipitocervical angle9°-22°group, occipitocervical angle<9°group, and occipitocervical angle>22°group. Immediate postoperative Oc-C2angle in9°-22°belonged to the normal angle range. S value and JOA score in each group were measured before and after fusion, during final follow-up. The statistics were compared. To different groups in occipital cervical fusion influence on cervical produced under different conclusions. RESULTS AND CONCLUSION:JOA scores in the occipitocervical angle9°-22°group, occipitocervical angle<9°group, and occipitocervical angle>22°group, were respectively,(7.3±1.7) points,(7.2±1.6) points, and (7.3±1.5) points, before fusion, and (14.2±1.5) points,(13.5±1.6) points and (13.3±1.5) points after fusion. JOA scores were improved significantly in the three groups. JOA improvement was significantly better in the occipitocervical angle9°-22°group than that in the occipitocervical angle<9°and>22°groups. C2-C7Angle values before fusion, pillow neck Angle of9°-22°group, pillow neck Angle<9°group, pillow neck Angle>22°group were24.83±15.5,25.64±14.6,25.22±15.6, no significant difference in group three. Pillow neck Angle of9°-22°group merged before final follow-up C2-C7Angle values and the fusion C2-there was no significant difference in C7Angle values, pillow neck Angle<9°team final follow-up after fusion C2-C7fusion Angle value from its former C2-C7Angle values are increased, and the pillow neck Angle>22°team final follow-up after fusion C2-C7fusion Angle value from its former C2-C7Angle values decrease obviously.Preoperative S values were respectively0.440±0.017,0.441±0.016, and0.440±0.018in the occipitocervical angle9°-22°group, occipitocervical angle<9°group, and occipitocervical angle>22°group, and no significant difference was detected among the three groups. No significant difference in S value was detectable in the occipitocervical angle9°-22°group between postoperative final follow-up and pre-operation. The S value was significantly smaller at postoperative final follow-up than pre-operation in the occipitocervical angle<9°and>22°groups.All patients were followed up after surgery of C2-C7and Oc-C2Angle after Pearson correlation is the correlation coefficient is0.859, namely the pillow neck Angle and negatively correlated with C2-C7Angle; Pillow neck Angle<9°group of postoperative follow-up of C2-C7compared with S value Pearson correlation, the correlation coefficient is0.769, it S value decreases with the increase of C2-C7Angle; Pillow neck Angle>22°group of postoperative follow-up of C2-C7compared with S value Pearson correlation, the correlation coefficient is0.192, namely with the decrease of the pillow neck Angle S value is smaller. Conclusion:These results indicated that during occipitocervical fusion, occipitocervical angle should try to be normal, more than or less than normal range will accelerate the degeneration of lower cervical spine. Therefore, when clinical line pillow cervical arthrodesis, intraoperative pillow neck Angle should be fixed in the physiological curvature, in order to minimize the impact of postoperative of the cervical spine.