Traumatic loading of the Bryan cervical disc prosthesis: an in vitro study.
OBJECTIVE
The Bryan disc prosthesis (Medtronic Sofamor Danek, Memphis, TN) relies on a precise fit between the device and the vertebral endplates to provide immediate stability after cervical arthroplasty. The safety of the cervical arthroplasty in the setting of trauma is unknown. We compare the segmental strength of the normal cervical spine and the cervical spine after single-level arthroplasty.


METHODS
Fifteen cadaveric cervical spines with arthroplasty placed at the C5-C6 level were compared with 16 intact cadaveric controls. A pure moment was applied to induce flexion, extension, or axial rotation until the segment failed.


RESULTS
The prosthesis provided 63, 45, and 69% of the strength of a normal spine during flexion, extension, and rotation, respectively. There were no cases of prosthesis expulsion.


CONCLUSIONS
After insertion of the Bryan disc, the remaining ligamentous tissues provide adequate acute stability to the spine.
Duggal
Neil
N
Division of Neurosurgery, University of Western Ontario, London, Canada.
Rabin
Doron
D
Chamberlain
Robert H
RH
Baek
Seungwon
S
Crawford
Neil R
NR
D000328:Adult; D000368:Aged; D002102:Cadaver; D002574:Cervical Vertebrae / Q000502:physiology*; D017586:Diskectomy; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019919:Prosthesis Implantation / Q000295:instrumentation*; D013123:Spinal Fusion / Q000295:instrumentation*; D013314:Stress, Mechanical; D013904:Thoracic Vertebrae / Q000502:physiology*; D014102:Torsion Abnormality