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 oneyear-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.

Comparison of sheep and human middle-ear ossicles: anatomy and inertial properties

“…According to studies by Seibel et al ( 2006a , b ), the average size of the middle and inner ears of the sheep is approximately two-thirds the average size of the middle and inner ears of the human. Thereby, the sheep has been used for research on bone conduction (Gerhardt et al 1996 ; McFadde et al 2008 ), training of middle- and inner ear surgeries (Gocer et al 2007 ; Cordero et al 2011 ; Mantokoudis et al 2015 ), and assessment of new surgical techniques and hearing devices (Lavinsky et al 1999 ; Neudert et al 2010 ; Miller et al 2014 ; Larsson et al 2015 ; Pfiffner et al 2018 ).…”

High‐resolution synchrotronX‐ray analysis of bioglass‐enriched hydrogels

“…Synchrotron X-ray imaging has been widely used in biomaterials research to image bone formation around titanium-based implants. [30][31][32][33][34] However, to our best knowledge, this is the first report on use of this technique to study hydrogel-particle composites in the biomaterials field.…”

Influence of Surface Processing on the Biocompatibility of Titanium

“…Furthermore, the affinity of titanium towards bone, known as osseointegration [ 13 ], leads to a stable fixation between the titanium prosthesis and the stapes footplate. Recent studies have tried to induce this process with osteoinductive substances covering the titanium stapes footplate [ 14 ].…”