Biomechanical analysis of anterior instrumentation for lumbar corpectomy.
METHODS
In vitro biomechanical assessment of spinal stability after corpectomy reconstruction. OBJECTIVES To gain a more thorough understanding of the biomechanical properties of anterior plate versus dual rod systems used for anterior lumbar corpectomy reconstruction.


BACKGROUND
Vertebral corpectomy is commonly required in the treatment of several types of spinal pathology (fracture, tumor, infection). Stabilization with strut allograft and anterior instrumentation can be accomplished with one of several anterior implant systems. These include plate systems and rod-based systems with theoretically different structural properties.


METHODS
Two instrumentation systems, the ATL Z-plate and the Antares system, were each applied to 10 calf lumbar spines with a cortical strut graft reconstructing an L3 corpectomy defect. All spines were tested biomechanically to determine construct stiffness under physiologic loads in multiple planes and then tested in torsion to failure.


RESULTS
There was greater stiffness (P < 0.05) in all directions of bending (flexion, extension, lateral bending) for the Antares dual rod construct compared to the Z-plate constructs. No significant difference was noted in either torsional testing under physiologic loads or torque to failure between the groups.


CONCLUSIONS
Although there was significantly greater resistance to bending with the dual rod construct, the ultimate selection of a system will require an individual analysis of implant profile, construct demand, and ease of use. Both systems provided secure initial fixation following lumbar corpectomy; however, the Antares system may increase the likelihood of graft incorporation in cases with greater instability and higher load demands.
Faro
Frances D
FD
University of California San Diego, San Diego, USA.
White
Klane K
KK
Ahn
Jae S
JS
Oka
Richard S
RS
Mahar
Andrew T
AT
Bawa
Maneesh
M
Farnsworth
Christine L
CL
Garfin
Steven R
SR
Newton
Peter O
PO
D000818:Animals; D001696:Biomechanical Phenomena; D001858:Bone Nails; D001860:Bone Plates; D002417:Cattle; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000601:surgery*