Evaluation of cruciate and slot auxiliary screw head design modifications for extracting stripped screw heads
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Updated: Jul 7, 2026

A Teleoperated Robotic System-Assisted Percutaneous Transiliac-Transsacral Screw Fixation Technique
Published on: January 6, 2023
Scott A Klein1, Nicholas A Kenney, John A Nyland
1Department of Orthopaedic Surgery, University of Louisville, Louisville, Kentucky 40202, USA.
Abstract:
Slotted and cruciate auxiliary screw head design modifications for "salvaging" a stripped hexagonal head screw were studied. Thirty screws were divided into 3 groups: Group 1 = control without modification, Group 2 = auxiliary cruciate design modification and Group 3 = auxiliary slot design modification. Screws were inserted into adhesive filled high-density synthetic bone tunnels using a hexagonal driver. Group 1 screws were removed using a hexagonal driver. Group 2 and group 3 screws were removed using drivers that matched their respective auxiliary design modifications. All group 1 and group 3 screws (100%) were effectively extracted. Three of 10 (30%) group 2 screws could not be effectively extracted. Group 2 screws displayed greater stripping and deformation than the other groups. The auxiliary slot design modification withstood comparable extraction torques as control screws without significant deformation. Screws with a cruciate design modification displayed more frequent failure, greater stripping and deformation.
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