Introducing a new possible predisposing risk factor for odontoid type 2 fractures after cervical trauma; Ponticulus posticus anomaly of C1 vertebra.

Objective: Ponticulus posticus is an anomaly of the atlas. Odontoid fracture type 2 fracture occurs by hyperflexion, hyperextension, lateral flexion, and a combination of these movements. The presence of Ponticulus Posticus anomaly may affect the occurrence of odontoid fractures of the C2 vertebra. In this study, the relationship between the presence of PP anomaly and occurring of the odontoid type 2 fracture was investigated.

Patients And Methods: Cervical CTs of a total of 14 patients with odontoid type 2 fracture were retrospectively evaluated for PP, and compared with 13 patients with cervical trauma without odontoid type 2 fracture.

Results: Ponticulus posticus anomaly was noted in 7 of 14 patients with odontoid type 2 fractures on the upper cervical CT; therefore, the prevalence was 50.%, but only 3 cases (23.07%) were seen in 13 patients of the control group. In binominal regression analysis showed that the presence of PP anomaly increases 12,075 times to occur odontoid type 2 fracture after cervical trauma.

Conclusion: Ponticulus posticus is often not recognized, but this study shows that ponticulus posticus is a risk factor for odontoid type 2 fracture after cervical trauma.