Atlantoaxial surgery through transoropharyngeal approach: an anatomical study / 解放军医学杂志

ABSTRACT

Objective To provide anatomical profile of the cranio-cervical region for the surgical treatment of ventral atlantoaxial lesions through transoropharyngeal approach.Methods Ten fresh specimens of craniocervical region were dissected layer by layer with microsurgical technic in accordance with the transoropharyngeal approach for the surgical treatment of atlantoaxial lesion, with special attention to anatomical stratification of pharyngeal posterior wall, the course of the vertebral artery, anatomical relation between the atlas and the axis, and anatomical parameters pertaining to internal fixation for the atlantoaxial joint. Results Pharyngeal posterior wall consisted of two layers (mucosa and prevertebral fascia) and two spaces (posterior interspace of pharynx and anterior interspace of vertebrae). Through anterior transoropharyngeal approach, the region between the anterior rim of the foramen magnum down to C 3 could be exposed. The distance between the vertebral artery and midline of the atlar and axis was 25.2?2.3mm(20.4-29.7mm) and 18.4?2.6mm(13.1-23.0mm) respectively. The exposed areas of the atlas and axis were 39.4?2.2mm(36.2-42.7mm) and midline was 39.0?2.1mm(35.8-42.3mm), respectively. The distance(a) between the two screw inserting points on the atlas (middle point of C 1 lateral mass) was 31.4?3.3mm(25.4-36.6mm). The vertical distance(b) between the connecting line of two screw inserting points on the atlas and that of two screw inserting points on the axis (3-4mm lateral to the midline of C 2 vertebra) was 18.7?2.7mm(14.9-23.2mm). The odds of a/b ranged from 1.5 to 1.7. Conclusion Atlantoaxial surgery through transoropharygeal approach is safe and feasible. The approach is suitable for internal fixation of anterior atlantoaxial joint, and the design of the plate should be based on the above data.