Brecknell J E, Malham G M
Department of Neurosurgery, The Alfred Hospital, Melbourne, Victoria, Australia.
J Clin Neurosci. 2008 Mar;15(3):295-301. doi: 10.1016/j.jocn.2006.07.022.
Os odontoideum is a condition in which a smoothly corticated ossicle exists dorsal to the anterior arch of C1, taking the place of the rostral dens, but with no bony connection to the body of the axis. Three patients presented with this condition: the first with Lhermitte's phenomenon 10 years after significant trauma, the second as an incidental finding during routine cervical spine imaging following a road traffic accident, and the third with recurrent transient quadriparesis precipitated by falls from a surfboard. Patients had at least 10 mm of sagittal instability on dynamic imaging and the second patient had a minimum sagittal canal diameter of only 11.5 mm. Posterior atlanto-axial fixation was successfully achieved in all cases using polyaxial screws and rods with the assistance of computed tomography-based image guidance. Image guidance provided an invaluable aid to preoperative planning and intraoperative placement of the posterior spinal instrumentation.
齿突骨是一种C1前弓背侧存在光滑皮质化小骨的情况，该小骨取代了齿突尖，但与枢椎体无骨性连接。有三名患者出现这种情况：第一名患者在严重创伤10年后出现莱尔米特氏现象，第二名患者在道路交通事故后的常规颈椎成像中偶然发现，第三名患者因从冲浪板上跌落而反复出现短暂性四肢轻瘫。动态成像显示患者矢状面不稳定至少10毫米，第二名患者矢状管最小直径仅为11.5毫米。所有病例均在基于计算机断层扫描的图像引导辅助下，使用多轴螺钉和棒成功实现了寰枢椎后路固定。图像引导为脊柱后路器械的术前规划和术中放置提供了非常宝贵的帮助。
