Screw placement in transoral atlantoaxial plate systems:: an anatomical study
Screw placement in transoral atlantoaxial plate systems:: an anatomical study
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DOI：
10.3171/spi.2001.95.1.0080
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发表时间：
2001-07-01
影响因子：
4.1
通讯作者：
Mittlmeier, T
中科院分区：
文献类型：
--
作者：
Kandziora, F;Schulze-Stahl, N;Mittlmeier, T
对象。经口齿状突切除术后寰枢前钢板的放置已由Harms描述。最近，生物力学和临床研究的作者表明，该手术，特别是与后路钢丝结合，是一种良好的替代方法，可以替代已建立的孤立后寰枢椎固定技术。关于寰椎和椎轴解剖的报道主要集中在后路手术入路。关于C-1和C-2前部定量解剖的研究很少有报道。本研究测量了C-1和C-2的相关尺寸及其与前经口入路的关系。本研究的目的是确定寰枢前钢板固定螺钉置入的“安全区域”。通过直接解剖、放射学和计算机断层扫描（CT）测量，获得了50块干的C-1和C-2椎骨。评估了32个线性参数和4个角参数。所有的测量都是用数字卡尺、尺子或测角仪进行的。解剖测量与相应椎骨的x线片（正位、侧位和颅侧）和CT （0.5 mm片厚度）测量相关。此外，还测量了20例患者的C-1和C-2的骨密度（BMD）。在双侧梯形寰椎中，前路螺钉置入的安全区域可以被描述。梯形内侧和外侧平均高度分别为4.1 +/- 1.01 mm（范围1.4-6.7 mm）和12.9 +/- 1.73 mm（范围8.7-17.4 mm）。矢状面与中、外侧壁的距离分别为10.2 +/- 1.42 mm（范围8.9 ~ 12.8 mm）和23.5 +/- 2.98 mm（范围21.7 ~ 30.7 mm）。侧面肿块矢状面平均深度22.3±2.04 mm（范围17.0 ~ 26.7 mm）。C-1安全区内的平均骨密度为0.89±0.11 g/cm(3)（范围0.75 ~ 1.01 g/cm(3)）。C-2骨矿物质密度测量显示齿状体底部有一个低密度的球体区（0.68 +/- 0.09 g/cm）。相反，骨密度高区出现在关节面附近（C1-2: 0.97 +/-0.11 g/cm）；C2-3: 0.94 +/- 0.12 g/cm(3))。前轴螺钉置入的安全区为v形，颅骨受低骨密度区限制，外侧受椎动脉沟限制。x线摄影与解剖测量的相关性一般较好（r(2) = 0.78-0.95），但CT与解剖测量的相关性较高（r(2) = 0.86-0.99）。在考虑经口齿状突切除术后寰枢前钢板固定时，定量了解C-1和C-2的前解剖是必要的。在这项研究中，作者定义了前寰椎和轴向螺钉置入的安全区域。正如Harms最初所描述的那样，寰枢前钢板仅部分尊重这些安全区。
Object. The placement of an anterior atlantoaxial plate after transoral odontoid resection has been described by Harms. Recently, the authors of biomechanical and clinical studies have shown that this procedure, especially in combination with posterior wiring, is a good alternative to established, isolated posterior atlantoaxial fixation techniques. Reports on the anatomy of the atlas and axis primarily focus on the posterior surgical approach. Scarce research regarding the quantitative anatomy of the anterior aspect of C-1 and C-2 has been reported. This study was undertaken to measure relevant dimensions of C-1 and C-2 and their relation to the anterior transoral approach. The aim of the study was to determine "safe zones" for screw placement in anterior atlantoaxial plate fixation.Method. Fifty human dry C-1 and C-2 vertebrae were obtained far direct anatomical, radiographic, and computerized tomography (CT) measurements. Thirty-two linear and four angular parameters were evaluated. All measurements were made using a digital caliper, ruler, or goniometer. Anatomical measurements were correlated with radiographic (anteroposterior, lateral, and craniocaudal) and CT (0.5-mm-slice thickness) measurements of the corresponding vertebrae. Additionally, bone mineral density (BMD) measurements of C-1 and C-2 were obtained in 20 patients.A safe zone for anterior screw placement in an atlas of bilateral trapezoid shape could be characterized. The average medial and lateral height of the trapezoid was 4.1 +/- 1.01 mm (range 1.4-6.7 mm) and 12.9 +/- 1.73 mm (range 8.7-17.4 mm), respectively. The distance between the sagittal plane and the medial and lateral walls of the trapezoid was 10.2 +/- 1.42 mm (range 8.9-12.8 mm) and 23.5 +/- 2.98 mm (range 21.7-30.7 mm), respectively. The average depth of the lateral masses was 22.3 +/- 2.04 mm (range 17.0-26.7 mm) in the sagittal plane. The average BMD in the safe zone of C-1 was 0.89 +/- 0.11 g/cm(3) (range 0.75-1.01 g/cm(3)). Bone mineral density measurements at C-2 revealed a spheroid zone of low density at the basis of the dens (0.68 +/- 0.09 g/cm(3)). In contrast, high zones of BMD were found near the articular surfaces (C1-2: 0.97 +/-0.11 g/cm(3); C2-3: 0.94 +/- 0.12 g/cm(3)). The safe zone for anterior axis screw placement was V-shaped, limited cranially by a zone of low bone density and laterally by the vertebral artery groove. Correlations between radiographic and anatomical measurements were generally good (r(2) = 0.78-0.95), but they were higher between CT and anatomical measurements (r(2) = 0.86-0.99).Conclusions. A quantitative understanding of the anterior anatomy of C-1 and C-2 is necessary when considering anterior atlantoaxial plate fixation after transoral odontoid resection. In this study the authors defined safe zones for anterior atlas and axis screw placement. The anterior atlantoaxial plate, as originally described by Harms, only partially respects these safe zones.