【摘要】 目的评价4种不同后路枕颈内固定方式的生物力学稳定性。方法选择6例新鲜尸体枕颈部标本,在标本完整状态(NS)、枕寰枢失稳模型(DS)、后路枕骨螺钉+C2椎弓根钉固定+纵棒固定(AF)、后路枕骨螺钉+C2椎弓根钉+C3侧块螺钉+纵棒固定(BF)、后路枕骨螺钉+C2椎弓根钉固定+C3椎板钩+纵棒固定(CF)、后路枕骨螺钉+C3椎板钩+C4椎板钩+纵棒固定(DF),共6种状态下,依次用KD-1型三维运动实验机进行测量相应节段的运动参数,并进行统计学分析。结果1.齿状突及横韧带切除后,枕颈部会严重失稳,即DS组运动范围(ROM)较NS组明显增大10-12%,具有显著性差异(P<0.05)。2.枕颈失稳后,AF组ROM明显比DS组减小13-16%(P<0.05),与NS组仅相差5-6%(P>0.05)。3.BF组ROM比失稳减小17-19%(P<0.05),更加有效抑制了枕颈部失稳。4.CF组ROM比DS组减小18-23%(P<0.05),亦有效抑制了枕颈部失稳。5.DF组ROM比DS组减小19-23%(P<0.05),也能有效抑制了枕颈部失稳,但椎板钩有滑动现象,相邻节段代偿运动加大。结论枕颈融合固定时,C2椎体骨质良好者,单纯C2椎弓根固定已足够稳定;在颈椎有C2椎弓根固定再加上C3侧块螺钉或C3椎板钩时,固定更坚强可靠,但多牺牲了一个椎体的活动度;颈椎以C3椎板钩+C4椎板钩固定时,也能达到可靠的枕颈固定,但有侧方滑动的趋势,同时固定的节段最长,邻近节段退变会加剧。更多还原

【Abstract】 objective To evaluate the biomechanical stability of four posterior internal fixation techniques for occipitocervical spine.Methods Six occipitocervical spines of fresh cadavers were classified for 6 subgroups as follows:normal samples(NS),removal of odontoid samples(DS),internal fixation of occipital screws and transpedicle screws of C2(AF),internal fixation from occipital screws to transpedicle screws of C2 and lateral mass screws of C3(BF),internal fixation from occipital screws to transpedicle screws of C2 and laminal hooks of C3(CF),and internal fixation of occipital screws and laminal hooks of C3 and C4(DF).With KD-1 3D motion testing device,the movement parameters of 6 subgroups samples were measured.The data were analyzed statistically.Results Range of motion(ROM)of DS group increases 10-12% compared to NS group(P<0.05).ROM of AF group decreased to 13-16% compared to DS group(P<0.05),but still increased nonsignificantly 5-6% as for NS group(P>0.05).And compared to the DS group,ROM of BF、CF and DF decrease 17-19%、18-23% and 19-23% respectively(P<0.05).In DF group,the laminal hooks had gliding tendency,and the compensatory activity of vicinity segments augmented.Conclusions To perform internal fixation of occipitocervical spine,occipital screws and transpedicle screws are stable enough biomechanically.If lateral mass screws or laminal hooks have been added in C3,the more stable can be obtained but the movement of C2-3 must be sacrificed.When laminal hooks of C3 and C4 were usedstability can be obtained,but the hooks have a tendency of lateral sliding,even more with the longest segment fixation,the junction segments degenerate faster.更多还原