title: Intraoperative assessment of ossicular fixation.
abstract: Determining the degree of ossicular fixation is a difficult task, with the final assessment often being made with manual palpation during exploratory tympanotomy. A more objective method to evaluate ossicular fixation would be valuable. In this paper we describe a new method which makes use of a magnet and coil to measure ossicular motion through the ear canal with an elevated tympanic membrane. We report measurements of the vibration response at the umbo, the tip of the incus long process and the lateral posterior crus of the stapes before and after artificially fixing the stapes footplate and anterior mallear ligament with luting cement. Results were obtained on temporal bones, but the practicality of the method allows easy clinical implementation. Velocity ratios between different measurement points along the ossicular chain may provide a quantitative indication of the degree of stapes fixation. Isolated anterior mallear ligament fixation was not distinguishable from the unfixed condition.
authors.affiliation: Laboratory of Biomedical Physics, University of Antwerp Groenenborgerlaan 171, B-2020, Antwerp, Belgium. Electronic address: peacockjohn@outlook.com.
authors.forename: John
authors.initials: J
authors.lastname: Peacock
authors.affiliation: Laboratory of Biomedical Physics, University of Antwerp Groenenborgerlaan 171, B-2020, Antwerp, Belgium. Electronic address: joris.dirckx@uantwerpen.be.
authors.forename: Joris
authors.initials: J
authors.lastname: Dirckx
authors.affiliation: Department of Otorhinolaryngology, Akershus University Hospital and University of Oslo, Oslo, Norway; Center for Clinical Research, University of Uppsala, Lt Vastmanland, Västerås, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: von Unge
mesh_terms: D000161:Acoustic Stimulation; D004429:Ear Ossicles / Q000601:surgery*; D006309:Hearing; D006314:Hearing Loss, Conductive / Q000601:surgery; D006801:Humans; D007188:Incus / Q000033:anatomy & histology; D008307:Malleus / Q000033:anatomy & histology; D009998:Ossicular Prosthesis; D013016:Sound; D013199:Stapes / Q000033:anatomy & histology; D013701:Temporal Bone / Q000033:anatomy & histology* / Q000502:physiology* / Q000601:surgery; D014432:Tympanic Membrane / Q000033:anatomy & histology*
keywords: Fixation of anterior mallear ligament (AML); Laser Doppler vibrometry; Stapes fixation