Strength and Fatigue Resistance of Thoracolumbar Spine Implants

1999; Lippincott Williams & Wilkins; Volume: 12; Issue: 5 Linguagem: Inglês

10.1097/00002517-199910000-00011

ISSN

1531-2305

Autores

Jeffery L. Stambough, Fadi El Khatib, Ashraf M. Genaidy, Ronald L. Huston,

Tópico(s)

Orthopaedic implants and arthroplasty

Resumo

Results of strength and endurance tests of several screw/rod thoracolumbar spinal implants are presented. The devices tested were: AcroMed ISOLA, CD systems, Depuy systems, and Synergy systems. The AcroMed ISOLA devices had the greatest stiffness and strength. The Synergy and AcroMed systems had the greatest fatigue resistance. The predominant failure mode was screw bending, although several instances of rod fracture and screw fracture were observed. A number of design improvements are identified, including reducing the number of components, thereby reducing the number of failure mechanisms; avoiding notches and knurled surfaces to provide greater resistance to crack initiation; and strengthening attachments between components, particularly between pedicle screws and horizontal rods.

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