Aim: To investigate the feasibility of placing a screw in the C2 lamina and evaluate the reliability of the surface of the dorsal arch of C2 as a landmark for determining the optimal site of screw entry.
Material and methods: 88 adult human C2 spines were used. Seven measurements were determined for screw entry points, trajectories, and lengths for placement of intralaminar screws.
Results: The average width of right C2 lamina (1/3 upper segment) was 2.6 mm (1.2 to 4.1 mm). The average width of left C2 lamina (1/3 upper segment) was 2.6 mm (1 to 4 mm). The average width of right C2 lamina (1/3 middle segment) was 4.9 mm (2.6 to 6.8 mm). The average width of left C2 lamina (1/3 middle segment) was 4.9 mm (2.3 to 7.6 mm). The average width of right C2 lamina (1/3 lower segment) was 5.7 mm (3.3 to 8.2 mm). The average width of left C2 lamina (1/3 lower segment) was 5.8 mm (2.2 to 9.6 mm).
Conclusion: The width of the upper one-third of C2 lamina is not appropriate for the placement of intralaminar screws. On the other hand, the width of the middle and lower one-third of C2 lamina is more convenient for intralaminar screw delivery.