TITLE:
Os Odontoideum: Report of Eight Cases and Review of the Literature
AUTHORS:
Bokhary Mahmoud, Wael Hammad, Ahmad Abdrabou
KEYWORDS:
Os Odontoideum, Craniocervical Junction Lesions, Atlantoaxial Instability
JOURNAL NAME:
Open Journal of Modern Neurosurgery,
Vol.10 No.4,
October
20,
2020
ABSTRACT: Background: Os odontoideum is a separate odontoid process from the body of the axis. It is a rare anomaly of the craniovertebral junction with evidence of both congenital and acquired causes but the aetiology still debated in the literature. It can lead to instability of the atlantoaxial joint and places the spinal cord at significant risk. Methods: Eight cases of os odontoideum were symptomatic at time of presentation, submitted for general and neurological examination, and investigated with different radiological modalities and managed with surgical fixation and stabilization. These patients followed for one year postoperatively. Results: The study includes six male patients and two female patients with median age 18.7 years. All patients presented with myelopathy and showed clinical evidence of atlantoaxial instability. They submitted for complete radiological investigations (plain x ray, CT scan and MRI) craniocervical junction. They underwent cervical surgical stabilization, two cases by atlantoaxial arthrodesis with wiring, two atlantoaxial fixation by lateral mass screw one of them with transoral odontoiectomy, two atlantoaxial fixations by a Rosen’s Hooks, and two cases craniocervical fixation by Tie frame. Death postoperatively recorded in two patients. Follow-up one year revealed resolution of symptoms in two patients and four patients remained stationary but without deterioration. Conclusion: Os odontoideum is a rare but sometimes lethal abnormality that requires radiological and clinical judgement to ensure the best choice of management and optimum patient’s care.