Biomechanical studies of an artificial disc implant in the human cadaveric spine.
OBJECTIVE
The authors compared the biomechanical performance of the human cadaveric spine implanted with a metallic ball-and-cup artificial disc at L4-5 with the spine's intact state and after anterior discectomy.


METHODS
Seven human L2-S1 cadaveric spines were mounted on a biomechanical testing frame. Pure moments of 0, 1.5, 3.0, 4.5, and 6.0 Nm were applied to the spine at L-2 in six degrees of motion (flexion, extension, right and left lateral bending, and right and left axial rotation). The spines were tested in the intact state as well as after anterior L4-5 discectomy. The Maverick disc was implanted in the discectomy defect, and load testing was repeated. The artificial disc created greater rigidity for the spine than was present after discectomy, and the spine performed biomechanically in a manner comparable with the intact state.


CONCLUSIONS
The results indicate that in an in vitro setting, this model of artificial disc stabilizes the spine after discectomy, restoring motion comparable with that of the intact state.
Hitchon
Patrick W
PW
Department of Neurosurgery, University of Iowa, Iowa City, Iowa 52242, USA. patrick-hitchon@uiowa.edu
Eichholz
Kurt
K
Barry
Christopher
C
Rubenbauer
Paige
P
Ingalhalikar
Aditya
A
Nakamura
Satoshi
S
Follett
Kenneth
K
Lim
Tae Hong
TH
Torner
James
J
D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D017586:Diskectomy / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019736:Prostheses and Implants; D016059:Range of Motion, Articular