Multidirectional stability of the graf system

P. J STRAUSS; J. E NOVOTNY; D. G WILDER; L. J GROBLER; M. H POPE

doi:10.1097/00007632-199404150-00016

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Multidirectional stability of the graf system

Journal article

Peer reviewed

Multidirectional stability of the graf system

P. J STRAUSS, J. E NOVOTNY, D. G WILDER, L. J GROBLER and M. H POPE

Spine (Philadelphia, Pa. 1976), Vol.19(8), pp.965-972

1994

DOI: 10.1097/00007632-199404150-00016

PMID: 8009356

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Abstract

Study design: To assess the biomechanical influences of the Graf fixation system on the spine, motion segments were tested. In normal spines, destabilized and restabilized with the Graf system conditions, the range of motion and flexibilities were found under various loading conditions. Objectives: These results should explain how the Graf Fixation system affects the biomechanical response of a motion segment. Methods: Motion segments (L2-3) and (L4-5) were subjected to these loading conditions: compressive loading, flexion-extension, lateral bending, and axial rotation moments. During the loading, the main and coupled motions were measured, and flexibilities were computed. The position of the balance point in axial loading was also determined. The motion segments were tested under three conditions: intact, destabilized, and restabilized. The destabilization consisted of a bilateral total laminectomy (pedicle-to-pedicle). Restabilization was affected with the Graf stabilization system, consisting of polyester bands between pedicle screw implants. Results: The total laminectomy significantly changed the balance point location by moving it forward. The restabilized motion segment had a balance point more similar to normal conditions. The mean compressive compliance was significantly less after application of the Graf system compared with destabilization. The range of motion for flexion-extension and axial rotation was significantly reduced for the main motion with the Graf system. For lateral bending, the main and coupled rotations were affected significantly, with lateral bending and flexion-extension motion reduced and axial rotation increased after restabilization. Restabilization decreased the flexibility of the destabilized motion segment for all of the moments. Conclusions: The Graf fixation system reduced the range of motion and the flexibility values in some loading conditions. These results only assess the immediate stabilization characteristics of this implant system in cadaveric material. Further research should address the fatigue characteristics.

Biological and medical sciences

Orthopedic surgery

Medical sciences

Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases

Details

Title: Subtitle: Multidirectional stability of the graf system
Creators: P. J STRAUSS - Spine inst. New England, Williston, United States
J. E NOVOTNY - Spine inst. New England, Williston, United States
D. G WILDER - Spine inst. New England, Williston, United States
L. J GROBLER - Spine inst. New England, Williston, United States
M. H POPE - Spine inst. New England, Williston, United States
Resource Type: Journal article
Publication Details: Spine (Philadelphia, Pa. 1976), Vol.19(8), pp.965-972
DOI: 10.1097/00007632-199404150-00016
PMID: 8009356
NLM abbreviation: Spine (Phila Pa 1976)
ISSN: 0362-2436
eISSN: 1528-1159
Publisher: Lippincott Williams & Wilkins; Philadelphia, PA; Hagerstown, MD
Language: English
Date published: 1994
Academic Unit: Roy J. Carver Department of Biomedical Engineering; Occupational and Environmental Health
Record Identifier: 9984064116502771

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24 Times Cited - Web of Science