下颈椎前路椎弓根螺钉内固定解剖学测量及临床应用

The study of anterior cervical pedicle screw channel in the lower cervical spine

目的通过解剖学测量和临床应用，探讨下颈椎前路椎弓根螺钉置人的可行性、安全性及其临床疗效。方法对20具成人颈椎标本通过CT扫描后进行数据测量，内容包括：椎体高度、椎体前后径、椎体宽度、椎弓根横径、椎弓根高度、螺钉长度、横切面角度、矢状面角度、横切面进针点距离、矢状面进针点距离，确定进针点，并进行尸体标本置钉。根据测量数据和术前影像学检查对5例颈椎骨折脱位患者行下颈椎前路椎弓根螺钉固定植骨融合术，术后观察复位及螺钉位置情况及短期随访结果。结果横切面角度从C3（45．7°±4．0°）至C5（52．1°±5．9°）逐渐增大，至C6（47．8°±6．7°）、C7（44．4°±8．3°）又有所减小。矢状面角度从C3（93．4°±7．2°）至C6（112．1°±6．2°）逐渐增大，至C7（102．7°±8．5°）又有所减小。横切面进针点C3-C5位于椎弓根对侧，C6-C7位于椎弓根同侧；矢状面进针点距离3．4-7．5mm。5例患者术中减压彻底，螺钉均位于椎弓根钉道内，日本骨科协会评分（Japanese Orthopaedic Association Scores，JOA）均有不同程度地提高。结论下颈椎前路椎弓根螺钉的理想进针点位于距上终板5mm左右，椎体前正中线附近。横切面角度约为45．7°-52．1°，矢状面角度约为93．4°-112．1°。螺钉长度约为32mm。

Objective To investigate application of the anterior cervical pediele screw in the lower cervical spine. Methods Twenty disartieulated human vertebrae （C3-C7） were evaluated with computed tomography for pediele morphometry Parameters included vertebral body height, vertebral body depth, vertebral body width, outer pediele width, outer pediele height, pedicle axis length, transverse section angle, sagittal section angle, transverse intersection point distance and sagittal intersection point distance. On the basis of these data, the screw channel was determined and the screws were inserted in the specimen. Five patients underwent surgical reconstruction using anterior pediele screw fixation. After surgery, physical examination and roentgenograms and CT scans were performed in all patients. Results The transverse section angle increased from C3（45.7°±4.0°） to C5（52.1°±5.9°）, but decreased from C6（47.8°±6.7°） to C7（44.4°± 8.3°）. The sagittal section angle gradually increased from C3 （93.40°±7.2°） to C6（ 112.1°±6.2°） but decreased a little to C7（102.7°±8.5°）. The distances in transverse section was about 1.97-3.98 mm and in sagittal section was 3.4-7.5 mm. Anterior pediele screws were inserted successfully in all specimens without critical pedicle wall perforations. Patients were permitted to ambulate the next day after surgery with a cervical collar. Postoperative neurological improvement was observed in all cases. Postoperative radiographic evaluation confirmed proper insertion of anterior pedicle screws without pediele perforaton. The average follow-up time was 10.6 months. No anterior pedicle screw breakage and loosening was observed. Conclusion The entry point in anterior pedicle screw should located in 5mm to upper endplate and near anterior median line. The transverse section angle should be 45.7°-52.1° and the sagittal section angle should be 93.4°-112.1°. The lengths of the screw should be about 32 mm.