Feasibility of translaminar screw placement in Korean population: morphometric analysis of cervical spine.

Purpose: To analyze the feasibility of unilateral and bilateral translaminar screw placement in Koran population, and compare the acceptance rate using previously reported data in American population. Materials and Methods: The translaminar lengths, thickness, heights, and sagittal-diagonal measurements were performed. The feasibility analysis was performed using unilateral and bilateral 3.5 mm cervical screw placement on the CT scans within 0.5 mm of safety margin. We also performed radiographic analysis of the morphometric dimensions and the feasibility of unilateral and bilateral translaminar screw placement at C3‒C7. Results: Korean population had similar or significantly shorter translaminar lengths and thickness (lengths and thickness in C7 among males; lengths in C6‒C7 and thickness in C4 among females) than American population, but had similar or signifi cantly longer translaminar heights and sagittal-diagonal measurements (heights in C3‒C7 and sagittal-diagonal measurements in C3‒C6 among males; heights in C7 and sagittal-diagonal measurements in C3‒C7 among females). Unilaterally, translaminar screw acceptance rates in C3‒C7 were similar between Korean and American male population, but the rates in C4‒C6 were significantly smaller between Korean and American female population. Bilaterally, translaminar screw acceptance rates in C3 and C5‒C6 were significantly larger between Korean and Ameri can male population, but the rates in C3‒C7 were similar between Korean and American female population. Conclusion: The feasibility of unilateral and bilateral translaminar screw placement is different depending on different ethnics. Subaxial cervical unilateral translaminar screw placement among Korean male population and bilateral placement at C4‒C7 among Korean female population are more acceptable than American population.