Background: Anterior cervical discectomy and fusion (ACDF) hardware failure can have serious complications for patients. Various advances in screw and plate design have increased the pullout strength of ACDF constructs, yet failure with screw pullout still occurs. One previously unexplored factor influencing pullout strength is the method of screw pilot hole creation. We aimed to compare pullout strength, stiffness, and strain of ACDF constructs in 3D-printed cervical spine vertebral bodies based on pilot hole creation with a drill versus an awl.

Methods: Spine models were 3D-printed into uniform testing blocks to mimic cervical vertebrae, according to previously validated methods. Four pilot holes per block for eventual screw placement were made with a 3 mm drill (n = 20) or a 3mm awl (n = 20). Using a biomimetic model, a plate and four 3.5 mm screws were affixed to each testing block. Pullout strength, stiffness, and strain of the final construct were collected. Maximum axial pullout forces and forces over distance curves were recorded for statistical analysis.