[Materials for reconstruction of the middle ear].
To rehabilitate most cases of conductive hearing loss closure of ear drum perforations and rebuilding of the ossicular chain can be performed. Due to the great number of biocompatible bone substitute materials available it is occasionally difficult for the surgeon to choose the most favorable substitute. Autogenous structures (ossicles, cortical bone, cartilage) and allogenous tissues (ossicles, cortical bone, cartilage, dentin) are possible bone replacement materials. Xenogenic tissue is currently not used in middle ear surgery. Ionomer cement is a hybrid material for replacement of bone but does not fit direct classification of the various classes of alloplastic materials in current use: that is, metals (gold, steel wire, platinum, titanium), plastics (polyethylene, polytetrafluorethylene) and ceramics (ceramic oxide, carbon, calcium-phosphate ceramic, vitreous ceramic). For restoration of the sound conductive apparatus preference is given to autogenous ossicles because cortical bone is resorbed and cartilage weakens over time. Most surgeons do not use allogenous tissue, because of the possible transmission of such infectious disease as immunodeficiency syndrome or Creutzfeldt-Jakob disease. Only dentin deserves special attention as a possible bone substitute in the middle ear because its form can be preserved during sterilization. Based on the observations available to date, it becomes apparent that titanium implants hold greater promise than gold. Form-stable synthetic materials are not generally recommended due to foreign body reactions which have been confirmed by many investigators. Ceramic materials (e.g. ceramic oxide, carbon, calcium-phosphate ceramic, glass ceramic) are well tolerated in the middle ear and have also proved to be useful over time. Hybrid bone substitute ionomer cement is easily workable and well integrated, showing a good functional outcome. For many years good results in otosclerosis surgery have been achieved with a prosthesis made of platinum-wire and Teflon. Short-term follow-up periods hold great promise with pistons made of gold. Autogenous ossicles, ionomer cement and recently titanium protheses--as far as usable--are employed by the author for reconstructing the middle ear. For the time being platinum-Teflon prostheses and gold are used in otosclerosis surgery.
Geyer
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Klinik für HNO-Heilkunde, Kopf- und Halschirurgie, Städtisches Klinikum Solingen.
D000818:Animals; D001672:Biocompatible Materials; D018786:Bone Substitutes; D016025:Bone Transplantation; D002516:Ceramics; D002986:Clinical Trials as Topic; D003804:Dentin; D004429:Ear Ossicles / Q000601:surgery; D004432:Ear, Middle / Q000601:surgery*; D006046:Gold; D006314:Hearing Loss, Conductive / Q000601:surgery*; D006801:Humans; D010040:Otosclerosis / Q000601:surgery; D017671:Platinum Compounds; D011138:Polytetrafluoroethylene; D012834:Silver; D014025:Titanium; D014433:Tympanoplasty / Q000295:instrumentation
D001672:Biocompatible Materials; D018786:Bone Substitutes; D017671:Platinum Compounds; D012834:Silver; D006046:Gold; D011138:Polytetrafluoroethylene; D014025:Titanium