Risk of Vertebral Artery Injury: A Comparison between C2 Subarticular Segmental and C1-2 Transarticular Screws / 대한정형외과학회잡지

ABSTRACT

PURPOSE: We compared the risk of vertebral artery injury associated with the insertion of C1-2 transarticular screws and C2 subarticular segmental screws using a computer simulation of computed tomography (CT) scans. MATERIALS AND METHODS: We simulated the placement of C1-2 transarticular screws and C2 subarticular segmental screws using 1-mm interval CT scan images in 166 patients, along with simulation software. We then determined the incidence of violation of the C2 vertebral artery groove. The same determination was performed for high-riding vertebral arteries found among those patients. RESULTS: Among the 332 C2 vertebral artery grooves (166 patients), C1-2 transarticular screws violated the groove in 33 (9.9%) instances, while C2 subarticular segmental screws violated the groove in 19 (5.7%) instances. The difference in incidence between the two screw types was statistically significant (p=0.001, McNemar test). In the 48 high-riding vertebral arteries, C1-2 transarticular screws led to violation of the C2 vertebral artery groove in 30 (62.5%) instances, while C2 subarticular segmental screws led to violation of the groove in 18 (37.5%) instances. The difference in incidence between the two screw types was statistically significant (p=0.002, McNemar test). CONCLUSION: Use of C2 subarticular segmental screws is associated with a lower risk of vertebral artery injury than is the use of C1-2 transarticular screws, even for high-riding vertebral arteries.