The effect of implant size and device keel on vertebral compression properties in lumbar total disc replacement
| Autor: | Frank L. Hammond, Joshua D. Auerbach, Carrie M. Ballester, Ehren T. Carine, Dawn M. Elliott, Richard A. Balderston |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Adult
Compressive Strength Bone density Joint Prosthesis medicine.medical_treatment Context (language use) Weight-Bearing Lumbar Bone Density Materials Testing medicine Humans Polymethyl Methacrylate Orthopedics and Sports Medicine Quantitative computed tomography Intervertebral Disc Reduction (orthopedic surgery) Aged Orthodontics Lumbar Vertebrae medicine.diagnostic_test business.industry Anatomy Middle Aged Biomechanical Phenomena Footplate Equipment Failure Analysis Surgery Neurology (clinical) Implant Cadaveric spasm business Diskectomy |
| Zdroj: | The Spine Journal. 10:333-340 |
| ISSN: | 1529-9430 |
| Popis: | BACKGROUND CONTEXT: Vertebral end plate support is necessary for successful lumbar total disc replacement (TDR) surgery. Failure to achieve anterior column support as a result of lumbar TDR device undersizing could lead to implant subsidence and fracture. PURPOSE: The purpose of the study was to examine the compressive biomechanical behavior of the vertebral end plate with varying sizes of disc replacement implants. STUDY DESIGN: The study design comprises a biomechanical investigation using a human cadaveric lumbar spine model. METHODS: Fifty-six vertebrae with intact posterior elements were prepared from 13 fresh frozen lumbar spines. Peripheral quantitative computed tomography was performed to assess regional bone density. Vertebrae were potted and subjected to nondestructive compression testing with a small, medium, and large custom-made implants with the footplate geometry of the ProDisc-LTDR (Synthes Spine, West Chester, PA, USA) system and having no keel. Failure testing was performed using the ProDisc-L implant with an intact keel. Pressure sensor film was used to assess contact pressure and distribution. RESULTS: Therewasalinearcorrelationbetweenpercentcoverageoftheendplateandimplant-end plate stiffness (p5.0001) and an inverse correlation with displacement (p5.01). The difference in implant-end plate stiffness between small-medium, medium-large, and small-large implants was 10.5% (p5.03), 10.2% (p5.02), and 19.6% (p!.0001), respectively. Failure analysis revealed similartrendsforimplantsizing,butonlybonedensitywasfoundtosignificantlycorrelatewithfailure properties (r50.76, p!.0001).Therewas a significant reduction in implant-end plate stiffness of 18% whenthekeelwasintactcomparedtowithoutthekeel(range6‐27%,p5.0008).Pressurefilmanalysis revealed that the implant was loaded peripherally and did not have central contact during nondestructiveloading.Therewasatrendtowardgreatercontactpressurewiththesmallimplantwhencompared with the medium implant (p5.06) and the large implant (p5.06). CONCLUSIONS: Although larger implants reduce end plate displacement, increase apparent implant-end plate stiffness, increase the implant-end plate contact area, and decrease the peak contact pressures, low bone density reduces failure properties. The keel introduces a reduction in stiffness to the implant-end plate interface, the clinical significance of which is currently |
| Databáze: | OpenAIRE |
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