顾勇杰(Guo Yongjie，Dept Spinal Surg，No.6 Hosp Ningbo，Ningbo 315040)…∥Chin J Trauma.－2011，27(2).－125～

Safety factors for anterior pedicle screw fixa-tion tun

顾勇杰(Guo Yongjie，Dept Spinal Surg，No.6 Hosp Ningbo，Ningbo 315040)…∥Chin J Trauma.－2011，27(2).－125～

ObjectiveTo investigate feasibility and safety of anterior pedicle screw fixation tunnel in the axis so as to provide theoretic evidence for further clinical application.MethodsThirty-two dry axis specimens were used for anterior pedicle screw placement，and the length of pedicle crews tunnel was measured by a digital caliper.The extraversion angle and the downslope angle were determined by CT cross-sectional scanning and reconstruction.ResultsAll the anterior pedicle screws were positioned well，with no perforation of the pedicle.The anchoring point was at the vertex between the vertebral body and the superior articular process，with axis pedicle length of(28.4 ± 2.5)mm，the extraversion angle of(28.5 ± 2.3)°and the downslope angle of(15.5 ±2.0)°.ConclusionAnterior pedicle screw fixation tunnel is feasible in the axis and can keep away from some important anatomy structures including transverse foramen，vertebral artery groove and vertebral canal to provide large safety space.

(Authors)