Reconstruction of the stapes superstructure with a combined glass-ceramic (Bioverit) implant in guinea pigs.

Background: Reconstruction of the stapes superstructure continues to be a problem for otologists. Optimal fixation of implants on the stapes footplate has not yet been achieved.

Methods: We postulated that bony fixation, between implant and stapes, could be confined exclusively to the footplate region by modifying the bioactivity of the implant material. Therefore, after removal of the superstructure in guinea pigs a combined biovitro ceramic implant (Bioverit I and Bioverit II) was placed on the stapes footplate in 10 guinea pigs. As a control, we employed a group of 6 animals in which the stapes superstructure was removed without placing any implant.

Results: After 25 weeks the implants were found to be dislocated laterally. We observed fixation with the wall of the middle ear. In the control group we also found new bone formation and even a bow shaped regeneration of the stapes superstructure.

Conclusion: Combined Bioverit stapedial implants were found to routinely fix to the middle ear wall of the guinea pig. The guinea pigs' enormous potential for bone regeneration in the middle ear ossicular chain make this species unsuitable for exploring hypotheses on human middle ear reconstruction.