Comparative Efficacy Study between Monocortical and Bicortical Screws in Anterior Cervical Fusion

ABSTRACT

The purpose of the study was to assess the role of two types screws(bicortical screws with 3.5mm diameter and monocortical screws with 4.5mm diameter) in anterior cervical spinal fusion. Seventy patients surgically treated on the same surgeon was retrospectively reviewed. All patients were managed as the same technique(modified Smith-Robinson technique) and the same non-locking plate system(Top plate system), but the bicortical screws were used in 40 patients(Group 1) and the monocorical screws in 30 patients(Group 2). The overall fusion rate during the 3 months follow up at least was to be satisfied on the both groups. The complication from the Group 2 was never seen but Group 1 was observed in 5 patients; one as slip of grafted bone, 2 as screw loosening, 1 as psychologic intolerance and 1 as CSF leakage. The monocortical screw was considered to be superior than bicortical screw and was related to the screw diameter.