椎弓根螺钉对腰椎关节突关节破坏率的研究

目的回顾性分析腰椎经椎弓根螺钉固定后对邻近的关节突关节破坏的发生率，从而提出选择较佳置钉的方法和减少钉杆结合部体积的设想。方法对1995—2003年行腰椎经椎弓根螺钉固定手术的143例患者，利用X线、CT扫描等影像学检查，评价经椎弓根螺钉对上关节突破坏的发生率。结果26．0％(157／604)的螺钉和31．5％(46／143)的患者存在固定节段椎体的上关节突不同程度的破坏。上关节突破坏的发生率主要与患者的关节突关节角有关。结论术前可借助CT等影像学检查，确定腰椎上关节突的关节角指导术中进钉，同时设计器械时尽量减少钉杆结合部的体积，可减少椎弓根螺钉对腰椎关节突关节的破坏，有助于提高患者的远期疗效。

Study of facet joints violation rate of lumbar spine after transpedicular instrumentation

Objective To study the incidence of adjacent superior segment facet joint violation following transpedicular instrumentation in the lumbar spine and hence to make an assumption that placement of screws is better and size of the head of the screw can be decreased. Methods A total of 143 patients undergoing lumbar spinal fusion surgery using transpedicular instrumentation between 1995 and 2003 were retrospectively evaluated with a computed tomography (CT) scan and plain radiographs at 6th month following surgery. Results CT scan showed that 26.0%(157/604) of the screws and 31.5%(46/143) of the patients had various degrees of facet joint violation. The facet joint violation was noted to be associated with the facet angle of the facet joints in the lumbar spine. Conclusions Preoperative CT scan is important to decide the facet joints angle for guiding screw fixation. Meanwhile, smaller size of the screw head in transpedicular screw design can not only be helpful for long-term results , but also decrease the possibility of transpedicular screws violating facet of lumbar spine.