title: In vivo degradation of magnesium plate/screw osteosynthesis implant systems: Soft and hard tissue response in a calvarial model in miniature pigs.
abstract: Biodegradable magnesium plate/screw osteosynthesis systems were implanted on the frontal bone of adult miniature pigs. The chosen implant geometries were based on existing titanium systems used for the treatment of facial fractures. The aim of this study was to evaluate the in vivo degradation and tissue response of the magnesium alloy WE43 with and without a plasma electrolytic surface coating. Of 14 animals, 6 received magnesium implants with surface modification (coated), 6 without surface modification (uncoated), and 2 titanium implants. Radiological examination of the skull was performed at 1, 4, and 8 weeks post-implantation. After euthanasia at 12 and 24 weeks, X-ray, computed tomography, and microfocus computed tomography analyses and histological and histomorphological examinations of the bone/implant blocks were performed. The results showed a good tolerance of the plate/screw system without wound healing disturbance. In the radiological examination, gas pocket formation was found mainly around the uncoated plates 4 weeks after surgery. The micro-CT and histological analyses showed significantly lower corrosion rates and increased bone density and bone implant contact area around the coated screws compared to the uncoated screws at both endpoints. This study shows promising results for the further development of coated magnesium implants for the osteosynthesis of the facial skeleton.
authors.affiliation: Department of Cranio-Maxillofacial Surgery, Inselspital, Bern University Hospital and University of Bern, CH-3010 Bern, Switzerland; National Dental Centre Singapore, 168938, Singapore. Electronic address: benoit.schaller@ndcs.com.sg.
authors.forename: Benoit
authors.initials: B
authors.lastname: Schaller
authors.affiliation: Department of Cranio-Maxillofacial Surgery, Inselspital, Bern University Hospital and University of Bern, CH-3010 Bern, Switzerland.
authors.forename: Nikola
authors.initials: N
authors.lastname: Saulacic
authors.affiliation: RMS Foundation, Bischmattstr. 12, CH-2544 Bettlach, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Imwinkelried
authors.affiliation: Synthes Biomaterials, Eimattstr. 3, CH-4436 Oberdorf, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Beck
authors.affiliation: National Dental Centre Singapore, 168938, Singapore.
authors.forename: Edwin Wei Yang
authors.initials: EW
authors.lastname: Liu
authors.affiliation: Department of Interventional and Diagnostic Neuroradiology, Bern University Hospital and University of Bern, CH-3010 Bern, Switzerland.
authors.forename: Jan
authors.initials: J
authors.lastname: Gralla
authors.affiliation: Department of Cranio-Maxillofacial Surgery, Inselspital, Bern University Hospital and University of Bern, CH-3010 Bern, Switzerland.
authors.forename: Ken
authors.initials: K
authors.lastname: Nakahara
authors.affiliation: Department of Clinical Research, University of Bern, CH-3010 Bern, Switzerland.
authors.forename: Willy
authors.initials: W
authors.lastname: Hofstetter
authors.affiliation: Department of Cranio-Maxillofacial Surgery, Inselspital, Bern University Hospital and University of Bern, CH-3010 Bern, Switzerland.
authors.forename: Tateyuki
authors.initials: T
authors.lastname: Iizuka
mesh_terms: D000818:Animals; D001860:Bone Plates; D001863:Bone Screws; D005593:Fracture Fixation, Internal; D008274:Magnesium; D013552:Swine; D013556:Swine, Miniature
chemical_list: D008274:Magnesium
keywords: Biomaterial; Degradation; Implant; Magnesium; Osteosynthesis