title: Titanium clip ball joint: a partial ossicular reconstruction prosthesis.
abstract: OBJECTIVE
  To describe a new titanium clip prosthesis for partial ossicular reconstruction with a micro ball joint in the headplate for compensation of tympanic membrane displacements.
  
  
  METHODS
  Laboratory experiments followed by 18 consecutive patients.
  
  
  METHODS
  A micro ball joint was implemented into a headplate of titanium middle ear prosthesis. First, the new prosthesis was tested in the laboratory in temporal bone experiments. Second, the new prosthesis was clinically installed in 18 patients.
  
  
  METHODS
  Results of laser Doppler vibrometry and force measurements in the laboratory experiments, analysis of a questionnaire, and preoperative and postoperative pure tone audiometry.
  
  
  RESULTS
  The frictional resistance in the joint was measured to be 12 mN that should allow for adequate mobility under physiologic conditions. The effective sound transmission of the prosthesis was demonstrated by laser Doppler vibrometry. Intraoperatively, the installation of the prosthesis was always straightforward with headplate prosthesis shaft angles between 60 and 90 degrees. Postoperatively, pure tone audiometry revealed satisfying hearing results with a remaining average air-bone gap of 18.2 dB over the frequencies 500, 1,000, 2,000, and 3,000 Hz. No signs of prosthesis dislocation were discovered within the follow-up period of approximately 6 months.
  
  
  CONCLUSIONS
  The experimental data show that the new modified prosthesis headplate fulfills the requirements necessary for sound transmission. The joint allows the plate to follow movements of the tympanic membrane. This characteristic in conjunction with the proven clip design ensure for optimal prosthesis placement and effectiveness.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Cologne, Germany. dirk.beutner@uni-koeln.de
authors.forename: Dirk
authors.initials: D
authors.lastname: Beutner
authors.forename: Jan Christoffer
authors.initials: JC
authors.lastname: Luers
authors.forename: Matthias
authors.initials: M
authors.lastname: Bornitz
authors.forename: Thomas
authors.initials: T
authors.lastname: Zahnert
authors.forename: Karl-Bernd
authors.initials: KB
authors.lastname: Huttenbrink
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001844:Bone Conduction / Q000502:physiology; D002648:Child; D004432:Ear, Middle / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009998:Ossicular Prosthesis; D019933:Ossicular Replacement / Q000295:instrumentation*; D019651:Plastic Surgery Procedures / Q000295:instrumentation*; D013701:Temporal Bone / Q000601:surgery*; D014025:Titanium
chemical_list: D014025:Titanium