[Biomechanical study of a ventral stand-alone cage for the lumbar spine with and without additional posterior fixation].
OBJECTIVE
Biomechanical study to examine the stability of a stand-alone cage (SAC; Topaz, Ulrich Medizintechnik, Ulm) incorporating integrated anterior fixation with and without additional posterior fixation.


METHODS
Six human spinal specimens (L4/5) were loaded in a spine tester in the three main motion planes in the following states: (a) intact, (b) defect (nucleotomy), (c) SAC, (d) SAC+internal fixator (IF), and (e) SAC+translaminar facet screws (TFS). Facet joint translation (FJT) and range of motion (ROM) were measured and used to evaluate the stability of the tested states.


RESULTS
The SAC stabilized the segment in comparison to the intact (a) and defect-containing (b) segments. The most rigid fixation was found for SAC+IF compared with the other states (a, b, c, e). The ROM and FJT of the SAC with the additional IF (d) showed a significant higher stability in all three motion planes. All differences in ROM and FJT between the tested states were statistically significant (p<0.05) except for the FJT SAC and SAC+TFS.


CONCLUSIONS
The ventral Topaz SAC is a stable implant for the lumbar spine. Additional dorsal stabilization is an option to increase the stability.
Vieweg
U
U
Abteilung für spezielle Wirbelsäulenchirurgie, Leopoldina-Krankenhaus, Schweinfurt, Germany.
Liner
M
M
Lühn
M
M
Neurauter
A
A
Blauth
M
M
Schmoelz
W
W
D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D017586:Diskectomy; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000503:physiopathology; D008159:Lumbar Vertebrae / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D019919:Prosthesis Implantation; D016059:Range of Motion, Articular / Q000502:physiology; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation; D013123:Spinal Fusion