Biomechanical Analysis of a Novel Pedicle Screw Anchor Designed for the Osteoporotic Population
| Autor: | Gary L. Dunbar, Mark Moldavsky, T A Gates, Jon Park, Kanaan Salloum, Brandon Bucklen |
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| Rok vydání: | 2015 |
| Předmět: |
Male
medicine.medical_specialty Polymers Population Biocompatible Materials Polyethylene Glycols Benzophenones Lumbar Pedicle Screws Suture Anchors medicine Humans Cement augmentation Two sample education Pedicle screw Aged Orthodontics education.field_of_study business.industry Significant difference Bone Cements Equipment Design Ketones Middle Aged Spine Biomechanical Phenomena Surgery Fatigue loading Osteoporosis Axial load Equipment Failure Female Neurology (clinical) business |
| Zdroj: | World Neurosurgery. 83:965-969 |
| ISSN: | 1878-8750 |
| Popis: | Objective The biomechanical study was performed to investigate the effect of a novel pedicle screw anchor in increasing the pullout strength of pedicle screws. Methods Ten lumbar vertebral bodies with a weighted average T-score of -2.13 were used. Pedicle screws of 4.5 mm diameter and 25 mm length were inserted in to one pedicle randomly and matched with an anchor in the corresponding pedicle. Fatigue testing was performed by applying an axial load of ±200N to the screw tulip, along the axis of the rod, at a rate of 0.5 Hz for 1,000 cycles. After fatigue loading was completed, all screws underwent axial pullout testing at a rate of 0.1 mm/sec until failure. A paired two sample for means t-test was performed to determine a significant difference between the two groups (p ≤ 0.05). Results Following fatigue testing, the axial displacement at the 1,000 cycle point for the anchor and non-anchor group was 1.4 ± 0.7mm and 2.9 ± 1.2mm, respectively. The anchor group had significantly lower axial displacement compared to the non-anchor group (p ≤ 0.01). The group with the anchor reached an average maximum load of 702 ± 373N. The average yield load for the non-anchor group was 421 ± 293N. The anchor group yield load was significantly greater than the non-anchor group (p ≤ 0.01). Conclusions A novel anchor for standard pedicle screws resulted in significantly less axial movement during fatigue and a greater failure force compared a screw with no anchor. The anchor may provide a stronger bone-to-screw interface, than a non-anchor screw, without the complications of cement augmentation. |
| Databáze: | OpenAIRE |
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