Original ArticlesBiomechanical Evaluation of Occipitocervical Fixation DevicesSutterlin, Chester E. III; Bianchi, John R.*; Kunz, David N.†; Zdeblick, Thomas A.‡; Johnson, Wesley M.§; Rapoff, Andrew J.§Author Information Florida Foundation for Research in Spinal Disorders, Gainesville; *Regeneration Technologies, Inc., Alachua, Florida; †Department of Mechanical Engineering, University of Wisconsin-Platteville, Platteville; ‡Division of Orthopaedic Surgery, University of Wisconsin, Madison, Wisconsin; and §Department of Aerospace Engineering, Mechanics & Engineering Science and Biomedical Engineering Program, University of Florida, Gainesville, Florida, U.S.A. Received August 25, 1999; accepted August 14, 2000. Address correspondence and reprint requests to Dr. C. E. Sutterlin III, Florida Foundation for Research in Spinal Disorders, 7120 NW 11th Place, Gainesville, Florida 32605, U.S.A. Journal of Spinal Disorders: June 2001 - Volume 14 - Issue 3 - p 185-192 Buy Abstract Human cadaveric occipitocervical specimens were implanted with three types of instrumentation. The devices were tested biomechanically under three modes of loading to determine the stiffness of spinal constructs and the failure mechanisms of the constructs under extreme flexion. The devices tested were the AXIS Fixation System (with custom plate), the Y-Plate, and the Luque rectangle. No significant differences in stiffness among the devices were found under compression and flexion. The stiffnesses of the plate systems were statistically higher than the Luque rectangle in extension and torsion. In extreme flexion, the plate systems failed by fracture of the C2 pedicles. Modern plate systems, for occipitocervical fixation, provide more stiffness and stability than traditional wiring techniques. This study provides surgeons with information on the relative merits of modern plate and screw systems compared with traditional rod and wire constructs. © 2001 Lippincott Williams & Wilkins, Inc.