title: Performance of functionally graded implants of polylactides and calcium phosphate/calcium carbonate in an ovine model for computer assisted craniectomy and cranioplasty.
abstract: Biodegradable functionally graded skull implants on the basis of polylactides and calcium phosphate/calcium carbonate were prepared in an individual mould using a combination of different processing techniques. A geometrically corresponding resection template was designed to enable a craniectomy and cranioplasty with the prepared implant in the same operation. After various preliminary experiments concerning degradation kinetics, pH evolution during degradation, micromorphology, biocompatibility tests in human osteoblast cell cultures and surgery of cadaver heads, a new large-animal model was developed for long-term in vivo studies. In eight 12-months-old sheep, the surgical templates were used to create 4.5 x 5 cm(2) calvarial defects which were then filled with the corresponding degradable implants in the same operation. The animals were sacrificed after 2, 9, 12 and 18 months, and the implants and the surrounding tissues were analysed by computer tomography (CT), macroscopic examination and microscopy. The new animal model proved to be reliable and very suitable for large individual craniectomies and cranioplasties. The formation of new bone from the dural layer of the meninges corresponded well to the degradation of the porous inner layer of the implants whereas the skull contour was stabilised by the compact outer layer over the follow-up period.
authors.affiliation: Department of Oral and Maxillofacial Plastic Surgery, Academic Teaching Hospital Recklinghausen, University of Bochum, Dorstener Street 150, 45657 Recklinghausen, Germany. harald.eufinger@ruhr-uni-bochum.de
authors.forename: Harald
authors.initials: H
authors.lastname: Eufinger
authors.forename: Christian
authors.initials: C
authors.lastname: Rasche
authors.forename: Jutta
authors.initials: J
authors.lastname: Lehmbrock
authors.forename: Michael
authors.initials: M
authors.lastname: Wehmöller
authors.forename: Stephan
authors.initials: S
authors.lastname: Weihe
authors.forename: Inge
authors.initials: I
authors.lastname: Schmitz
authors.forename: Carsten
authors.initials: C
authors.lastname: Schiller
authors.forename: Matthias
authors.initials: M
authors.lastname: Epple
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001861:Bone Regeneration; D002119:Calcium Carbonate / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D003399:Craniotomy / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D006863:Hydrogen-Ion Concentration; D021621:Imaging, Three-Dimensional; D008297:Male; D023421:Models, Animal; D011091:Polyesters / Q000737:chemistry*; D012756:Sheep; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D014057:Tomography, X-Ray Computed
chemical_list: D001672:Biocompatible Materials; D002130:Calcium Phosphates; D011091:Polyesters; C033616:poly(lactide); C020243:calcium phosphate; D002119:Calcium Carbonate