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Conclusions: With the aggravation of the external auditory canal malformation, the size of extra-niche fossa became smaller, providing concrete data and valuable information for the better design, selecting and safer implantation of the transducer in the area of round window niche. Three-dimensional measurements and assessments before surgery might be helpful for a safer surgical approach and implantation of a vibrant soundbridge., Objectives: The aim of this study was to investigate whether differences exist in the morphology of the posterior tympanum related to the round window vibroplasty among congenital aural atresia (CAA), congenital aural stenosis (CAS), and a normal control group, and to analyze its effect on the round window implantation of vibrant soundbridge., Methods: CT images of 10 normal subjects (20 ears), 27 CAS patients (30 ears), and 25 CAA patients (30 ears) were analyzed. The depth and the size of outside fossa of round window niche related to the round window vibroplasty (extra-niche fossa)and the distances between the center of round window niche and extra-niche fossa were calculated based on three-dimensional reconstruction using mimics software. Finally, the data were analyzed statistically., Results: The size of extra-niche fossa in the atresia group was smaller than in the stenosis group (p < 0.05); furthermore, the size of extra-niche fossa in the stenosis group was smaller than that of the control group (p < 0.05). There was no statistically significant difference of the depth of extra-niche fossa among different groups.

Conclusion: High-resolution computed tomography (CT) scan may reveal an isolated fenestral form of otosclerosis, and an extensive form, which involves multiple foci around the otic capsule. Pre- and postoperative hearing thresholds are poorer in patients with extensive otosclerosis and their chance of overclosure is reduced by 90%., Objectives: To evaluate the relationship between CT scan extension of otosclerotic foci and hearing thresholds in the operated ear, before and after stapedotomy., Methods: A preoperative CT scan was performed in 200 patients suspected of having otosclerosis. CT scan findings were categorized as negative, isolated fenestral otosclerosis, and extensive otosclerosis. Preoperative and 2 months postoperative air-conduction (AC) and bone-conduction (BC) thresholds were collected., Results: In the operated ear, 150 CT scans (75%) revealed an isolated fenestral otosclerosis; 35 (17.5%) were classified as extensive otosclerosis. Mean preoperative BC was significantly poorer in extensive otosclerosis (30.3 dB) than in isolated fenestral otosclerosis (24.6 dB). Mean postoperative BC remained lower in extensive otosclerosis (30.3 dB) than in isolated fenestral otosclerosis (21.2 dB). An overclosure greater than 10 dB was found in 20% of isolated fenestral otoscleroses and in 2.85% of extensive otoscleroses (chi-square: 5.5; p = 0.02).

Conclusion: In agreement with previously published findings, our results demonstrate that Pelizaeus Merzbacher disease (PMD) does not affect the development and morphology of the peripheral vestibulo-cochlear system., Objective: PMD is a consequence of X-linked mutation of the main central nervous system (CNS) myelin protein resulting in a complex neurological syndrome. Otorhinolaryngological symptoms include nystagmus and alterations of auditory-evoked brainstem responses. To date no histopathological analysis of the inner ear has been performed., Materials and Methods: The temporal bone morphology of an affected fetus was examined with light microscopy and synchrotron radiation-based micro computed tomography., Results: The regular structure of the vestibulo-cochlear system was shown in this multi-modular analysis.

Surgical ligation of the external auditory canals of Mongolian gerbils produces aural cholesteatomas that are similar to spontaneous gerbilline cholesteatomas. These experimental cholesteatomas expand rapidly, medially displacing the tympanic membrane and eroding bone. Less than 2 months after ligation, half these cholesteatomas are in contact with the bony prominence of the cochlea. Ligation-induced formation of cholesteatomas may be unique to the gerbil. Keratin deposits are produced by similar ligations of the external auditory canals of cats, guinea pigs, hamsters, mice, and rats. However, in these animals there is no medial displacement of the tympanic membrane, no cholesteatoma formation, and no bone erosion. Cholesteatomas were not seen in cats, guinea pigs, hamsters, mice, and rats even after post-ligation intervals of 6 to 36 months.

Proplast implants were used in reconstruction of the posterior ear canal wall in one ear and in obliteration of the cavity in two ears. All ears healed well but the canal wall implant became visible in 15 months and had to be removed because of persistant suppuration. The other two implants became visible 3 to 4 years postoperatively. Plastipore TORPs were implanted in two ears undergoing revision surgery. One prosthesis was removed several months later because of infection, and the other 1 year after surgery, as no improvement in hearing had been achieved. Histologically, masses of giant cells were seen in the implants and many cells had engulfed both the vitreous carbon material of Proplast and the white Teflon material of both Proplast and Plastipore. It is concluded that Proplast is unsuitable either for canal wall reconstruction or for cavity obliteration. Plastipore should be used only as a bridge between two ossicles. If the implant must be applied to the tympanic membrane, that end should be fitted with a nonabsorbable bony homograft, which does not cause foreign body reaction.

The present paper describes the setting-up of a new project, sponsored by the Commission of the European Communities, to promote the study of functional histopathology of the human audio-vestibular organ. The project has the purpose of co-ordinating in Europe morphological research on the hearing and equilibrium organ and promoting the comparison of data from clinical, physiological and morphological studies in the field of hearing and equilibrium impairment. A manual (Iurato et al., 1982) has been prepared with the objectives of (1) stimulating clinicians to participate in the project, (2) encouraging the collection of audiological data for comparison with pathology, and (3) supplying clinicians with the necessary information about the technique of fixation and preparation of the specimens. The fixation procedures for the two major techniques of studying ear pathology: (1) microdissection and electron microscopy, and (2) embedding of the whole block for serial sectioning and light microscopy, are described in detail. Special paragraphs deal with the technique of fixation of the brain and with the technique of removal of the temporal bones and brain at autopsy. The instructions for delivery of the specimens and the publication rules are enclosed in the main body of the manual. Appendix 1 contains a list of the participating laboratories. Appendix 2 deals with autopsy legislation in the different European countries. Appendix 3 contains the sender's data sheet which supplies the instructions for collecting the clinical history of the patient and the audiological and vestibular data.

Twenty-eight chinchillas received continuous or intermittent infrasound (1, 10, 20 Hz) at 150, 160, or 170 dB SPL; there were 7 controls. Serial sections of the temporal bones were examined using light microscopy. Pathologies noted were tympanic membrane perforation, stapes subluxation, bleeding from the middle ear mucosa and tensor tympani, strial pathology, Reissner's membrane rupture, endolymphatic hydrops, saccular wall rupture, hair cell damage, and blood in the cochlear scalae. Continuous infrasound was more damaging than intermittent. Only continuous infrasound produced saccular pathology and perforations of the tympanic membrane. Of the other pathologies observed, continuous infrasound exposures produced 67% of the hair cell damage, 73% of the bleeding in the cochlear scalae, 83% of the strial pathology, and 78% of the cases of cochlear hydrops. 170-dB infrasound exposures produced the highest percentage of ears with pathologies of the three exposure intensities. As frequency increased the percentage of ears with pathologies decreased.