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方法:在7例新鲜人颅颈段标本上采用经口咽逐级扩大入路行经斜坡置钉枕颈固定：单纯经口咽入路、经口咽软腭切开入路、经口咽软硬腭切开入路、经口咽下颌骨切开入路、经口咽下颌骨-舌体切开入路。在切开入路过程中观察咽后壁软组织的分布并测量其厚度，观察椎动脉走行及其至中线的距离，测量斜坡的显露范围、椎骨显露范围及斜坡置钉角度范围（下切牙或下颌骨基底中点处至斜坡显露端的连线与斜坡骨面切线的夹角）。结果:咽后壁软组织厚度于斜坡咽结节以上为（3.5±0.6）mm，Cn 1~Cn 5椎前为（5.0±0.5）mm。双侧椎动脉至中线的距离在Cn 1，2、Cn 2，3、Cn 3，4和Cn 4，5水平分别为（19.5±1.2）mm、（14.6±2.7）mm、（14.0±2.7）mm和（13.9±2.7）mm。单纯经口咽入路：斜坡显露纵径为（8.3±3.0）mm，下切牙至斜坡显露上缘、斜坡下缘、Cn 1前结节、Cn 2椎体及Cn 3椎体的距离分别为（104.7±4.3）mm、（99.2±6.8）mm、（81.4±4.3）mm、（75.1±4.0）mm及（68.7±6.5）mm；6例标本颈椎显露达Cn 3椎体，1例显露至Cn 2椎体。经口咽软腭切开入路：斜坡显露纵径为（18.5±4.8）mm，下切牙至斜坡显露上缘、咽结节距离分别为（107.9±6.7）mm、（104.8±6.7）mm。经口咽软硬腭切开入路：斜坡显露纵径为（26.3±1.8）mm（斜坡全长），下切牙至斜坡显露上缘的距离为（112.4±12.6）mm。经口咽下颌骨切开或下颌骨-舌体切开入路均显露斜坡全长，下颌骨基底中点处至斜坡上、下缘及咽结节的距离分别为（141.8±15.7）mm、（131.0±9.9）mm及（120.5±8.2）mm；颈椎显露最下缘可达Cn 5，6椎间隙。单纯经口咽入路由于斜坡显露范围不够，无法完成斜坡理想置钉；经口咽软腭切开入路和经口咽软硬腭切开入路的斜坡置钉率分别为71%（5/7例）和86%（6/7例），置钉角度为92.6°±7.7°；经口咽下颌骨或下颌骨-舌体切开入路的斜坡置钉率为100%，置钉角度为75.1°±7.7°。n 结论:经口咽软腭切开及软硬腭切开入路基本能满足前路枕颈固定术的斜坡置钉要求。对口裂较小或张口受限、颅底扁平、颅底凹陷所致斜坡倾斜角度较小或需下颈椎固定重建者，应采用经口咽下颌骨切开入路。“,”Objective:To evaluate the feasibility of the screw and plate for clival fixation using a transoral expanded approaches.Methods:The transoral expanded approaches were performed on craniocervical segment specimens obtained from 7 subjects, including transoral approach (TO), transoral with soft (TOP) or hard (TOHP) palate split, mandibulotomy (MO) and mandibuloglossotomy (MLO). The distribution and thickness of soft tissue, the configuration of the vertebral arteries, the distance between the midline and the vertebral arteries, the exposed area of the clivus and cervical spine, and the range of screw angle (the angle between the line from the lower incisor or the central base of the mandible to the exposed area of the clivus and the tangent line of the clivus) were evaluated.Results:The thickness of the soft tissue on the posterior pharyngeal wall above the clival pharyngeal nodules was 3.5±0.6 mm. That on the anterior Cn 1-Cn 5 vertebrae was 5.0±0.5 mm. The distances from the bilateral vertebral arteries to the midline was 19.5±1.2 mm at Cn 1, 2, 14.6±2.7 mm at Cn 2, 3, 14.0±2.7 mm at Cn 3, 4, and 13.9±2.7 mm at Cn 4, 5. For the TO approach, the longitudinal diameter of the exposed clivus was 8.3±3.0 mm. The distance from the lower incisor to the superior margin of the exposed clivus, the lower margin of the exposed clivus, the anterior arch of Cn 1, the vertebral body of Cn 2 and Cn 3 were 104.7±4.3 mm, 99.2±6.8 mm, 81.4±4.3 mm, 75.1±4.0 mm and 68.7±6.5 mm, respectively. Six specimens were exposed to the Cn 3, while one was exposed to the Cn 2. For the TOP approach, the longitudinal diameter of the exposed clivus was 18.5±4.8 mm. The distance from the lower incisor to the superior margin of the exposed clivus and the pharyngeal nodules were 107.9±6.7 mm and 104.8±6.7 mm, respectively. For the TOHP approach, the longitudinal diameter of the exposed clivus was 26.3±1.8 mm (the clival length) with distance from the lower incisor to the superior margin of the clivus 112.4±12.6 mm. For the MO/MLO approach, the entire clivus was exposed. The distance from the central base of the mandible to the superior and inferior margin of the exposed clivus and the pharyngeal nodules were 141.8±15.7 mm, 131.0±9.9 mm and 120.5±8.2 mm, respectively. The inferior margin of the exposed cervical vertebra was Cn 5, 6. The rate of the clival screw placement through anterior occipitocervical fixation using TO, TOP, TOHP, MO and MLO was 0%, 71% (5/7), 86% (6/7), and 100%, respectively. The screw angle was 99.0°±1.8°, 92.6°±7.7°, 92.6°±7.7°, 75.1°±7.7°, and 75.1°±7.7°, respectively.n Conclusion:Occipitocervical fixation with clival screw and plate could be conducted in most cases via TOP and TOHP approaches. However, in some cases with small split-mouth or mouth opening limited, smaller clival screw angle caused by basilar impression or basilar invagination, requiring fixation and reconstruction of the lower cervical spine, and the MO/MLO approaches could be still required to achieve the fixation.