[Biomechanical properties of synthetic lumbar intervertebral disk implants].
OBJECTIVE
The aim of this study was to determine the influence of two different artificial nucleus implants for lumbar discs on the biomechanical properties of the spinal motion segment.


METHODS
From 7 calf spines, the lumbar segments L2/3 and L4/5 were harvested, the lamina and the muscles were removed with care to preserve the anterior and posterior longitudinal ligament. The segments were fixed on a special testing device mounted in an universal testing machine (Zwick, Ulm, Germany). Physiological load with a maximum of 7 Nm was applied in flexion/extension, right and left side bending, and right torsion. Three cycles of measurement were performed in all specimen: a) the intact segment, b) segment after nucleotomy, c) 6 segment with 2 PDN devices (Ray Medica) and 8 segments with an autopolymerized polymer.


RESULTS
There was a statistically significant (p = 0.0078/p = 0.0313) increase in segmental mobility in all directions after nucleotomy. After introduction of two PDN implants as well as the polymer implant, there was a restoration of segmental mobility for all movement directions with no statistically significant difference (p > 0.05) compared to the intact situation before nucleotomy.
Zöllner
J
J
Orthopädische Universitätsklinik Mainz. zoellner@mail-uni-mainz.de
Rompe
J D
JD
Eysel
P
P
D000818:Animals; D001696:Biomechanical Phenomena; D002417:Cattle; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000503:physiopathology / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications / Q000503:physiopathology*; D019919:Prosthesis Implantation; D016059:Range of Motion, Articular / Q000502:physiology