Load sharing in Premier and Zephir anterior cervical plates.
METHODS
An in vitro biomechanical study using a simulated anterior cervical discectomy and interbody fusion model to compare the load sharing properties of two semiconstrained cervical (Premier and Zephir) plates.


OBJECTIVE
To determine the percent load transmission through these plates and grafts under simple axial compression.


BACKGROUND
No published data exist as to the load transmission through these semiconstrained plates.


METHODS
Cadaveric calf spines were subjected to axial compression loading while instrumented with an interbody graft and with the graft plus one of the plates. Load transmission was computed through an analysis of the load-displacement data.


RESULTS
A mean load transmission of 23% was shared by the Premier plate. The Zephir, a more constrained plate but still semiconstrained, shared a mean of 32% of the load.


CONCLUSIONS
The semiconstrained plates tested allow more graft loading than some previously tested constrained plates. However, there are differences between the research methods used in these studies that provide a less than satisfactory comparison.
Rapoff
Andrew J
AJ
Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611-6250, USA. rapoff@ufl.edu
Conrad
Bryan P
BP
Johnson
Wesley M
WM
Cordista
Andrew
A
Rechtine
Glenn R
GR
D000818:Animals; D001860:Bone Plates; D002417:Cattle; D002574:Cervical Vertebrae / Q000601:surgery*; D019245:Compressive Strength; D017586:Diskectomy; D013123:Spinal Fusion; D016474:Weight-Bearing