The effect of posterior non-fusion instrumentation on segmental shear loading of the lumbar spine
Article dans une revue avec comité de lecture
Date
2014Journal
Orthopaedics and Traumatology - Surgery and ResearchAbstract
Background : Lumbar stenosis and facet osteoarthritis represent indications for decompression and instrumentation. It is unclear if degenerative spondylolisthesis grade I with a remaining disc height could be an indication for non-fusion instrumentation. The purpose of this study was to determine the influence of a mobile pedicle screw based device on lumbar segmental shear loading, thus simulating the condition of spondylolisthesis. Materials and methods : Six human cadaver specimens were tested in 3 configurations: intact L4–L5 segment, then facetectomy plus undercutting laminectomy, then instrumentation with lesion. A static axial compression of 400 N was applied to the lumbar segment and anterior displacements of L4 on L5 were measured for posterior-anterior shear forces from 0 to 200 N. The slope of the loading curve was assessed to determine shear stiffness. Results : Homogenous load-displacement curves were obtained for all specimens. The average intact anterior displacement was 1.2 mm. After lesion, the displacement increased by 0.6 mm compared to intact (P = 0.032). The instrumentation decreased the displacement by 0.5 mm compared to lesion (P = 0.046). The stiffness's were: 162 N/mm for intact, 106 N/mm for lesion, 148 N/mm for instrumentation. The difference was not significant between instrumented and intact segments (P = 0.591). Conclusions : Facetectomy plus undercutting laminectomy decreases segmental shear stiffness and increases anterior translational L4–L5 displacement. Shear stiffness of the instrumented segment is higher with the device and anterior displacements under shear loading are similar to the intact spine. This condition could theoretically be interesting for the simulation of non-fusion instrumentation in degenerative spondylolisthesis.
Files in this item
Related items
Showing items related by title, author, creator and subject.
-
Article dans une revue avec comité de lecturePRUD'HOMME, Marion; BARRIOS, Carlos; CHARLES, Yann-Philippe; STEIB, Jean-Paul; SKALLI, Wafa; ROUCH, Philippe (Lippincott, Williams & Wilkins, 2015)Fusion is the standard in-strumentation for many pathologies of the lumbar spine. Wor-rying rates of failure, including adjacent segment degeneration (ASD), have consistently been reported. The interest for dy-namic ...
-
Limiting interpedicular screw displacement increases shear forces in screws: A finite element study Article dans une revue avec comité de lectureBackground context: Screw loosening has been reported for non-fusion devices. Forces on pedicle screwscould be related to kinematic parameters as the interpedicular displacement (ID), which consists of thedisplacement ...
-
Article dans une revue avec comité de lectureNTILIKINA, Yves; CHARLES, Yann Philippe; PERSOHN, Sylvain; SKALLI, Wafa (Springer Verlag, 2020)Purpose This in vitro biomechanical study compares residual lumbar range of motion (ROM) and rod strain after lumbopelvic instrumentation using 2 rods, 4 rods and interbody cages. Methods Seven human cadaveric specimens ...
-
Article dans une revue avec comité de lectureMEIBODY-TABAR, Farid; BENKORIS, Mohamed; RAZIK, Hubert; PIETRZAK-DAVID, Maria; MONMASSON, Eric; BOUSCAYROL, Alain; DAVAT, Bernard; DELARUE, Philippe; HAUTIER, Jean-Paul; LOUIS, Jean-Paul; PIERFEDERICI, Serge; SEMAIL, Eric (2005)Cet article présente le principe de décomposition de machines polyphasées en machines fictives monophasée et diphasées non couplées magnétiquement. Après la description de la méthodologie de décomposition SMM (Systèmes ...
-
Article dans une revue avec comité de lectureLOISEL, François; DURAND, Stan; PERSOHN, Sylvain; AUBRY, Sébastien; LEPAGE, Daniel; BONNET, Xavier; SKALLI, Wafa (Elsevier, 2020)The scapholunate joint is one of the keystones of the wrist kinematics, and its study is difficult due to the carpal bones size and the richness of surrounding ligaments. We propose a new method of quantitative assessment ...