Comparative biomechanical testing of anterior and posterior stabilization procedures.
METHODS
This is a comparative in vitro biomechanical study in a calf lumbar spine model.


OBJECTIVE
The objective was to compare the primary stability of an anterior instrumentation, an intercorporal cage in combination with an anterior instrumentation, and a posterior instrumentation for monosegmental spondylodesis.


BACKGROUND
Spondylodesis can be achieved through a posterior lumbar fusion, posterior lumbar intercorporal fusion, or an anterior lumbar intercorporal fusion. The posterior lumbar fusion is the gold standard, although the anterior approach offers some potential advantages to the transpedicular posterior techniques.


METHODS
Stability testing was performed on 30 calf lumbar spine motion segments in a physiologic state (n = 30), with either an isolated anterior (MACS) or posterior instrumentation (SOCON), and with an anterior instrumentation augmented with an intercorporal cage (MACS-Cage, n = 10, respectively). Range of motion, neutral zone, and bending stiffness were measured under pure bending to 10 Nm, and bending stiffness under axial loads of up to 1500 N.


RESULTS
The isolated posterior instrumentation was found to be more stable than the isolated or augmented anterior instrumentation in flexion/extension, although no significant differences were observed in lateral bending or axial rotation. The results of this biomechanical study suggest that an augmented anterior instrumentation provides similar stability for bony fusion as does the golden standard posterior instrumentation, with the exception of flexion/extension.


CONCLUSIONS
An augmented anterior instrumentation may provide similar stability for bony fusion as does the posterior instrumentation.
Department of Orthopaedics, Hannover Medical School, Hannover, Germany. flamme@annastift.de
Christian H
CH
Flamme
Christof
C
Hurschler
Caroline
C
Heymann
Nadine
N
von der Heide
D000818:Animals; D001696:Biomechanical Phenomena; D002417:Cattle; D015194:Diffusion Chambers, Culture; D066298:In Vitro Techniques; D008159:Lumbar Vertebrae / Q000502:physiology* / Q000601:surgery*; D009068:Movement; D016059:Range of Motion, Articular; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods*; D014102:Torsion Abnormality