Failure of synthes anterior cervical fixation device by fracture of Morscher screws: a biomechanical study. J Spinal Disord 1994 Apr;7(2):120-5
Date
04/01/1994Pubmed ID
8003828DOI
10.1097/00002517-199407020-00004Scopus ID
2-s2.0-0028211581 (requires institutional sign-in at Scopus site) 15 CitationsAbstract
Anterior cervical fixation using the Synthes system has become increasingly popular. Two screw types for anchoring the plates include a "solid" titanium expansion screw and a plasma-sprayed fenestrated expansion screw that permits bony ingrowth. These screws were compared clinically and in the laboratory. In our first 20 cases using Synthes plates secured by Morscher fenestrated screws, 3 failures were observed, unilaterally in 1 patient and bilaterally in 2 others. In the unilateral screw failure, the contralateral screw was "solid" and did not fail. In the mechanical studies, screws were secured in the Synthes plate and embedded into methylmethacrylate and subjected to a sinusoidal bending moment to the mid-shaft of the screw. Load deflection data and cycles to failure were recorded. Fenestrated screws were found to demonstrate nearly twice as much deformation at failure and tolerated significantly fewer cycles to failure than did "solid" screws (p < 0.05). Because benefits of bony ingrowth into the screw are not well identified, the risks of fenestrated screw failure should preclude their routine use.
Author List
Hollowell JP, Reinartz J, Pintar FA, Morgese V, Maiman DJAuthor
Frank A. Pintar PhD Chair, Professor in the Biomedical Engineering department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AdultBiomechanical Phenomena
Bone Plates
Bone Screws
Cervical Vertebrae
Equipment Design
Equipment Failure
Equipment and Supplies
Female
Humans
Materials Testing
Radiography
