RARE CONGENITAL ANOMALIES AT THE CRANIOVERTEBRAL JUNCTION; OS ODENTOIDEUM

Aim: We aimed to identify dislocation, myelomalacia, and other congenital pathologies that may cause neurological complications arising from the odontoid process in the craniocervical junction (CVJ) of patients who were performed cervical tomography due to various complaints. Materials and Methods: Patients who were performed cervical CT with various complaints between 2010 and 2018 were retrospectively screened and evaluated, from the hospital registry system. Segmentation and fusion anomalies arising from the odontoid process in the craniovertebral junction area, as well as other accompanying pathologies such as subluxation, dislocation, compression to the spinal cord, and myelomalacia were also recorded. An additional 1.5 Tesla cervical MRI was performed for the 12 patients with os odontoideum. Radiological evaluation was performed on the workstation by an experienced radiologist. Results: 2525 patients with cervical CT were included in the study. 67 of these patients had congenital anomalies at the CVJ. 13 of 67 patients had os odontoideum, 38 had Klippel-Feil syndrome (KFS). Atlanto-occipital assimilation (AOA) and KFS often saw together. Only AOA was observed in 16 cases. Neck pain and limitation of movement were the most common findings in patients with congenital anomalies in the CVJ region. Conclusion: Congenital anomalies at the CVJ region, although rare, can cause mortality or morbidity. Cervical CT and MRI studies on the CVJ region should be evaluated carefully by the clinicians due to the risk of various complications.