Pain and infection are the primary reasons for elective retrieval of bone-anchored implants

Abstract

Purpose: Elective removal of bone-anchored hearing implants and epistheses is uncommon, limiting the understanding of the biological factors contributing to adverse reactions, implant success or failure. Therefore, the tissue-level response at the implant interface remains poorly understood. Methods: This study examined 21 explanted bone-anchored implants and interfacial tissues from 19 patients using a controlled retrieval protocol. The clinical data were correlated with histological, immunohistochemical, microbiological, and structural analyses. Results: Pain (12/19) and infection (7/19) were the most common reasons for elective implant retrieval and in 5 cases occurred together. All explants, apart from one, showed significant osseointegration and maintained stability in situ, independent of their design characteristics. Staphylococcus aureus was isolated in five patients—four of whom reported pain even without overt infection. Staphylococcus epidermidis was detected in two patients: one with pain and infection and the other asymptomatic with a resolved infection. S. aureus colonization was associated with intense inflammation, marked by the presence of neutrophils, iNOS+ macrophages, CD3 + T-cells, and CD20 + B-cells. Conclusion: Pain and infection—often involving Staphylococcus species—are key drivers of implant retrieval. These findings emphasize the complex immune response at the implant site and the diagnostic value of analysing electively retrieved implants for improving patient outcomes.