• H Frei, T R Oxland, G C Rathonyi, and L P Nolte.
• Maurice E. Müller Institute for Biomechanics, University of Bern, Switzerland.
• Spine. 2001 Oct 1; 26 (19): 2080-9.

Study DesignAn in vitro biomechanical investigation on human cadaveric specimens was conducted before and after nucleotomy. Endplate and vertebral body deformation patterns were measured under compression and shear loading, in addition to kinematics and disc pressure.ObjectiveThe working hypotheses of this study were that in compression, nucleotomy results in an altered deformation pattern of the endplate and that in shear, nucleotomy does not result in an altered endplate deformation pattern or disc pressure.Summary Of Background DataThe pressure distributions within the intervertebral disc have been studied in compression loading but not in shear loading. Severe degeneration and surgical nucleotomy result in small nuclear pressure and altered loading distribution in compression. The effect of these changes on the vertebral endplate and the response under shear loads are not well understood.MethodsFive L3-L4 and two L4-L5 functional spinal units were tested under compression and shear loading, intact and after nucleotomy. Vertebral body deformations, intradiscal pressure, and intervertebral kinematics were measured. A series of compression-type (maximum 1000 N) and shear-type (maximum 500 N) loads were applied.ResultsWith nucleotomy, the disc pressure and the endplate strains decreased under compression, but the vertebral rim strains did not change. In shear, the vertebral rim and endplate strains did not change with nucleotomy. Disc pressure was lower in shear than in compression.ConclusionNucleotomy resulted in decreased disc pressure, decreased endplate deformation, and modified loading patterns onto the inferior vertebra in compression loading. However, nucleotomy did not appreciably affect the behavior of the disc in shear loading.

23 keywords...

hide…