C2 intralaminar screw placement: a quantitative anatomical and morphometric evaluation.

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.