Faculty Collaboration Database

Finite element analysis of cervical facetectomy. Spine (Phila Pa 1976) 1997 May 01;22(9):964-9

Date

05/01/1997

Pubmed ID

9152445

DOI

10.1097/00007632-199705010-00006

Scopus ID

2-s2.0-0030922724 (requires institutional sign-in at Scopus site)   79 Citations

Abstract

STUDY DESIGN: Moment-rotation responses and disc anulus stresses of intact and facetectomized C4-C6 cervical spinal units were analyzed using detailed, three-dimensional, finite element models.

OBJECTIVES: To evaluate biomechanical effects of progressive unilateral and bilateral facet resections on cervical spine segmental mobility (external response) and disc anulus stress (internal response).

SUMMARY OF BACKGROUND DATA: Experimental studies have demonstrated that facetectomy significantly increases segmental mobility of the cervical spine. The biomechanical effects of facetectomy on the internal response, however, have not been investigated.

METHODS: Moment-rotation responses of C4 with respect to C6 and von Mises stress in the disc anulus were examined using finite element models of a 0% (intact), 25%, 50%, 75%, and 100% unilaterally and bilaterally facetectomized cervical spinal unit. The model simulations were conducted under the pure-moment loading of 1.8 Nm in flexion, extension, lateral bending, and axial torsion. The intact model also was validated experimentally under the same conditions.

RESULTS: The moment-rotation responses of the intact unit were within the ranges of experimental data. Cervical rotations increased with the increased degree of facet resection. The greatest change occurred between 50% and 75% facet resections in bilateral facetectomy. Similar patterns were found for disc anulus stresses, but to a greater extent. The maximum increase in rotation (11%) and in anulus stress (30%) occurred in lateral bending. Torsion was the least affected loading mode. The effects of unilateral facetectomy were considerably less than those of 75% bilateral facetectomy.

CONCLUSIONS: Facetectomy has a greater effect on anulus stress than on intervertebral joint stiffness. Significant increase in anulus stresses and segmental mobility may occur when bilateral facet resection exceeds 50%.

Author List

Voo LM, Kumaresan S, Yoganandan N, Pintar FA, Cusick JF

Authors

Joseph F. Cusick MD Adjunct Professor in the Neurosurgery department at Medical College of Wisconsin
Frank A. Pintar PhD Chair, Professor in the Biomedical Engineering department at Medical College of Wisconsin
Narayan Yoganandan PhD Professor in the Neurosurgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adult
Biomechanical Phenomena
Cervical Vertebrae
Elasticity
Female
Humans
Laminectomy
Models, Anatomic
Range of Motion, Articular
Rotation
Stress, Mechanical