title: Can the Hydroxyapatite-Coated Skin-Penetrating Abutment for Bone Conduction Hearing Implants Integrate with the Surrounding Skin?
abstract: BACKGROUND
  Percutaneous implants, such as bone conduction hearing implants, suffer from complications that include inflammation of the surrounding skin. A sealed skin-abutment interface can prevent the ingress of bacteria, which should reduce the occurrence of peri-abutment dermatitis. It was hypothesized that a hydroxyapatite (HA)-coated abutment in conjunction with soft tissue preservation surgery should enable integration with the adjacent skin. Previous research has confirmed that integration is never achieved with as-machined titanium abutments. Here, we investigate, in vivo, if skin integration is achievable in patients using a HA-coated abutment.
  
  
  METHODS
  One titanium abutment (control) and one HA-coated abutment (case) together with the surrounding skin were surgically retrieved from two patients who had a medical indication for this procedure. Histological sections of the skin were investigated using light microscopy. The abutment was qualitatively analyzed using scanning electron microscopy.
  
  
  RESULTS
  The titanium abutment only had a partial and thin layer of attached amorphous biological material. The HA-coated abutment was almost fully covered by a pronounced thick layer of organized skin, composed of different interconnected structural layers.
  
  
  CONCLUSIONS
  Proof-of-principle evidence that the HA-coated abutment can achieve integration with the surrounding skin was presented for the first time.
authors.affiliation: Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center , Maastricht , Netherlands.
authors.forename: Marc
authors.initials: M
authors.lastname: van Hoof
authors.affiliation: Cochlear Bone Anchored Solutions AB , Mölnlycke , Sweden.
authors.forename: Stina
authors.initials: S
authors.lastname: Wigren
authors.affiliation: Institute of Nanoscopy, Maastricht University Medical Center , Maastricht , Netherlands.
authors.forename: Hans
authors.initials: H
authors.lastname: Duimel
authors.affiliation: Department of Medical Microbiology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center , Maastricht , Netherlands ; Department of Medical Microbiology and Infection Control, VU University Medical Center , Amsterdam , Netherlands.
authors.forename: Paul H M
authors.initials: PH
authors.lastname: Savelkoul
authors.affiliation: Cochlear Bone Anchored Solutions AB , Mölnlycke , Sweden.
authors.forename: Mark
authors.initials: M
authors.lastname: Flynn
authors.affiliation: Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center , Maastricht , Netherlands.
authors.forename: Robert Jan
authors.initials: RJ
authors.lastname: Stokroos
keywords: Baha; SEM; adverse skin reactions; bone conduction hearing implant; histology; hydroxyapatite; skin integration