Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.
Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
World Neurosurg. 2019 Dec;132:e324-e332. doi: 10.1016/j.wneu.2019.08.160. Epub 2019 Aug 30.
To assess the value and limitation of cervical traction in the evaluation of the reducibility of atlantoaxial dislocation (AAD) and basilar invagination (BI) using the intraoperative O-arm.
A total of 22 patients with hyperextensive, irreducible AAD were included. The cervical traction test under general anesthesia was performed, and the degree of reduction was evaluated using the O-arm before the operation started. The traction effects both vertically and horizontally were evaluated. All cases then underwent modified direct posterior reduction and fixation. Clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scale. Radiologic measurements included the anterior atlantodental interval, the distance of odontoid tip above Chamberlain line, and the clivus-canal angle. Magnetic resonance imaging signal changes, size of syringomyelia, and the space ventral to medulla also were used to evaluate the postoperative reduction result.
After the cervical traction test, 7 patients achieved incomplete reduction, 5 achieved only vertical reduction, 6 achieved only horizontal reduction, and 4 achieved complete reduction in both horizontal and vertical orientations as assessed by the O-arm. All patients underwent a direct reduction technique. The mean JOA score increased from 11.1 to 14.5. Complete reduction of AAD and BI were achieved in 19 patients (86.4%), with partial reduction achieved in 3 (13.6%). Sufficient cerebrospinal fluid space anterior to the medulla with improved JOA score was achieved in the 3 partially reduced patients.
With the innovations of direct posterior reduction techniques, cervical traction under anesthesia may not sufficiently predict the reducibility of BI and AAD. Cervical traction still plays an important role during the direct posterior reduction procedure.
评估术中 O 臂在评估寰枢关节脱位（AAD）和颅底凹陷症（BI）可复性中的价值和局限性。
共纳入 22 例伸展过度、不可复位的 AAD 患者。在全身麻醉下进行颈椎牵引试验，在手术开始前使用 O 臂评估复位程度。评估垂直和水平方向的牵引效果。所有病例均行改良直接后路复位固定。采用日本矫形协会（JOA）量表评估临床疗效。影像学测量包括寰齿前间距、齿状突尖距 Chamberlain 线的距离以及斜坡-椎管角。磁共振成像信号变化、脊髓空洞大小和延髓腹侧空间也用于评估术后复位效果。
颈椎牵引试验后，7 例患者获得不完全复位，5 例仅获得垂直复位，6 例仅获得水平复位，4 例在 O 臂评估下获得水平和垂直方向的完全复位。所有患者均行直接复位技术。JOA 评分从 11.1 分增加到 14.5 分。19 例（86.4%）患者 AAD 和 BI 完全复位，3 例（13.6%）患者部分复位。3 例部分复位患者的延髓前脑脊液空间充足，JOA 评分改善。
随着直接后路复位技术的创新，麻醉下颈椎牵引可能无法充分预测 BI 和 AAD 的可复性。颈椎牵引在直接后路复位过程中仍发挥重要作用。
