title: Osseointegration of titanium prostheses on the stapes footplate.
abstract: The success of middle ear reconstructive surgery depends on stable coupling between the prosthesis and residual ossicles. To establish a stable fixed point on the stapes footplate for subsequent prosthesis reconstruction, a titanium footplate anchor was coated with osteoinductive substances to induce a controlled osseointegration on the footplate. Various studies have shown that collagen-based matrices with and without bone growth and differentiation factors can induce and enhance bone formation and consequently increase implant stability. The ears of 23 one-year-old Merino sheep (n = 46) were divided into five groups and implanted with a specially designed footplate anchor. The surface of each implant was modified by applying a collagenous matrix (collagen I or II) either with immobilized bone morphogenic protein (BMP-4) or transforming growth factor-ss, respectively, to stimulate osteoblastic activation and differentiation on the stapes footplate with subsequent osseointegration. Polychrome labeling was used to assess new bone formation and remodeling during the study. After study termination on day 84, synchrotron radiation-based computed microtomography and histomorphometry were used to identify bone implant contact. Eight implants showed radiographical and/or histological evidence of integration by newly formed bone. An osseointegration could histologically be proven in two of these eight specimens, and additional ectopic bone formations were seen in another 21 specimens. In all animals, bone turnover on the footplate was proven by polychrome labeling. This study proves the general ability to induce a controlled osseointegration of titanium implants biologically activated with artificial extracellular matrices on their surfaces on the stapes footplate in a mammalian organism.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Technische Universität Dresden, Fetscher Strasse 74, 01307, Dresden, Germany. marcus.neudert@uniklinikum-dresden.de
authors.forename: Marcus
authors.initials: M
authors.lastname: Neudert
authors.forename: Thomas
authors.initials: T
authors.lastname: Beleites
authors.forename: Michael
authors.initials: M
authors.lastname: Ney
authors.forename: Anne
authors.initials: A
authors.lastname: Kluge
authors.forename: Nikoloz
authors.initials: N
authors.lastname: Lasurashvili
authors.forename: Matthias
authors.initials: M
authors.lastname: Bornitz
authors.forename: Dieter
authors.initials: D
authors.lastname: Scharnweber
authors.forename: Thomas
authors.initials: T
authors.lastname: Zahnert
mesh_terms: D000818:Animals; D055415:Bone Morphogenetic Protein 4 / Q000494:pharmacology; D002809:Chondroitin Sulfates / Q000494:pharmacology; D020099:Coated Materials, Biocompatible; D024042:Collagen Type I / Q000494:pharmacology; D024043:Collagen Type II / Q000494:pharmacology; D058575:Decorin; D005109:Extracellular Matrix; D016326:Extracellular Matrix Proteins / Q000494:pharmacology; D005260:Female; D023421:Models, Animal; D016348:Osseointegration / Q000502:physiology*; D019933:Ossicular Replacement / Q000379:methods*; D011475:Prosthesis Failure; D011509:Proteoglycans / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D012756:Sheep; D013199:Stapes / Q000000981:diagnostic imaging / Q000502:physiology*; D013201:Stapes Surgery; D014025:Titanium; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014433:Tympanoplasty; D055114:X-Ray Microtomography
chemical_list: D055415:Bone Morphogenetic Protein 4; D020099:Coated Materials, Biocompatible; D024042:Collagen Type I; D024043:Collagen Type II; D058575:Decorin; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D002809:Chondroitin Sulfates; D014025:Titanium