Development of open-cell polyurethane-based bone surrogates for biomechanical testing of pedicle screws.
Artificial bones made of polyurethane are frequently used as an alternative to human bone for biomechanical testing. However, the biomechanical characteristics of these materials are often not validated against those of human bones. Thus, synthetic bone surrogates reflecting procedure-specific biomechanical properties of human bones are necessary for reliable implant design and testing. The aim of this study was to evaluate novel custom made open- and close-cell bone surrogates through morphometry assessment and pedicle screw pullout tests as an alternative to human bone for biomechanical testing. Bone surrogates created from polyurethane resin, mineral fillers and varying amounts of blowing agent were customized to various densities. Pedicle screws were manually inserted and pullout tests with a feed rate of 1 mm/min were conducted until failure. Load and displacement curves were recorded and analyzed in terms of maximum pullout forces. The resulting pullout forces of open- (1437 ± 665 N) and close-cell surrogates (951 ± 578 N) showed comparable results to human bone (1417 ± 812N) used as a reference. Furthermore, structural morphometric parameters were in accordance with human vertebral cancellous bone. In conclusion, the customized bone surrogates provide a new opportunity to design and test pedicle screws and further study the relationship between biomechanical properties and apparent density of artificial spongy bone.
['Hollensteiner|Marianne|M|', 'Esterer|Benjamin|B|', 'Fürst|David|D|', 'Schrempf|Andreas|A|', 'Augat|Peter|P|']
D000368:Aged D000369:Aged, 80 and over D001696:Biomechanical Phenomena D018786:Bone Substitutes D005260:Female D006801:Humans D008297:Male D008422:Materials Testing D008875:Middle Aged D065289:Pedicle Screws D011140:Polyurethanes D011312:Pressure D013131:Spine D014057:Tomography, X-Ray Computed
Biomechanics Morphology Open-cell cancellous bone Synthetic vertebral bone Vertebra