Fig. 3

Represents the examination results of a 2-year-old male with eosinophilic granuloma of odontoid process accompanied by atlantoaxial dislocation. He was treated with poterior C1/2 pedicle screw internal fixation followed by transoral lesion resection of odontoid process. The X-rays (see a and b) show anterior atlantoaxial dislocation. As shown in c and d, the CT further reveals atlantoaxial dislocation, bone destruction in odontoid process of C2, and space occupying lesions. According to e, f, g and h, CTs show the lesions are mainly distributed in the odontoid process and lumbar region of C2, and no obvious lesions are found in the basal region. The postoperative X-rays (see i and j) immediately show that the atlantoaxial segment has been completely reducible, and the internal fixation is in good position. As shown in k, l, m, n, o, p, q, r and s, the atlantoaxial segment has been repositioned, and all the screw paths are in good position, without any invasion of vertebral artery holes and spinal canals. The postoperative MRI results (see t and u) demonstrate the odontoid lesion at atlantoaxial level has been removed. According to v and w, X-rays conducted 3 months after operation show that the internal screw fixed in atlantoaxial segment is in place without obvious loosening or displacement. X-rays (see x) conducted 6 months after operation demonstrate that the atlantoaxial internal fixation is firm without any obvious dislocation. In addition, the physiological curve of cervical spine is good, and there is no instability of adjacent segments