Middle ear mechanics in normal, diseased and reconstructed ears

1998 ◽  
Vol 112 (8) ◽  
pp. 715-731 ◽  
Author(s):  
Saumil N. Merchant ◽  
Michael E. Ravicz ◽  
Susan E. Voss ◽  
William T. Peake ◽  
John J. Rosowski
Keyword(s):  
Structure Function ◽  
Tympanic Membrane ◽  
Middle Ear ◽  
Ossicular Chain ◽  
Acoustic Stimulation ◽  
Tympanic Membrane Perforation ◽  
Acoustic Coupling ◽  
Type Iv ◽  
Middle Ear Mechanics ◽  
Wide Range

AbstractA review of the structure-function relationships in normal, diseased and reconstructed middle ears is presented. Variables used to describe the system are sound pressure, volume velocity and acoustic impedance. We discuss the following(1) Sound can be transmitted from the ear canal to the cochlea via two mechanisms: the tympanoossicular system (ossicular coupling) and direct acoustic stimulation of the oval and round windows (acoustic coupling). In the normal ear, middle-ear pressure gain, which is the result of ossicular coupling, is frequency-dependent and smaller than generally believed. Acoustic coupling is negligibly small in normal ears, but can play a significant role in some diseased and reconstructed ears.(2) The severity of conductive hearing loss due to middle-ear disease or after tympanoplasty surgery can be predicted by the degree to which ossicular coupling, acoustic coupling, and stapes-cochlear input impedance are compromised. Such analyses are used to explain the air-bone gaps associated with lesions such as ossicular interruption, ossicular fixation and tympanic membrane perforation.(3) With type IV and V tympanoplasty, hearing is determined solely by acoustic coupling. A quantitative analysis of structure-function relationships can both explain the wide range of observed postoperative hearing results and suggest surgical guidelines in order to optimize the post-operative results.(4) In tympanoplasty types I, II and III, the hearing result depends on the efficacy of the reconstructed tympanic membrane, the efficacy of the reconstructed ossicular chain and adequacy of middle-ear aeration. Currently, our knowledge of the mechanics of these three factors is incomplete. The mechanics of mastoidectomy and stapedectomy are also discussed.

scholarly journals Recovery from tympanic membrane perforation: Effects on membrane thickness, auditory thresholds, and middle ear transmission

2019 ◽  
Vol 384 ◽  
pp. 107813 ◽  
Author(s):  
Lingling Cai ◽  
Glenna Stomackin ◽  
Nicholas M. Perez ◽  
Xiaohui Lin ◽  
Timothy T. Jung ◽  
...  
Keyword(s):  
Tympanic Membrane ◽  
Middle Ear ◽  
Tympanic Membrane Perforation ◽  
Membrane Thickness ◽  
Auditory Thresholds ◽  
Membrane Perforation

Middle Ear Packing: Comparison Between Merogel and Gelfoam

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P102-P102
Author(s):  
Michael Julian Lipan ◽  
Alava Ibraham ◽  
Simon I Angeli ◽  
Thomas R Van De Water
Keyword(s):  
Tympanic Membrane ◽  
Middle Ear ◽  
Inflammatory Reaction ◽  
Tympanic Membrane Perforation ◽  
Mucosal Inflammation ◽  
Controlled Study ◽  
Control Group ◽  
Otologic Surgery ◽  
Membrane Perforation ◽  
Brainstem Response

Problem Gelfoam has been used for decades in otologic surgery to support grafts and prostheses despite causing fibrosis and adhesions. More biocompatible packing materials could avoid these complications. This study compares Gelfoam with an injectable esterified hyaluronic acid, Merogel, as middle ear packing material after mucosal trauma. Methods A randomized, blinded, controlled study was performed in 17 juvenile guinea pigs. Middle ear surgery with mucosal trauma was performed and middle ears were packed with Merogel or Gelfoam; unpacked contralateral ears were used as controls. Auditory brainstem response (ABR) thresholds were measured in 4 frequencies pre-operatively, and repeated at 1, 2, and 6 weeks postoperatively. Gross analysis measured inflammatory reaction in each group. Statistical analysis was performed using ANOVA followed by post-hoc analysis for ABR thresholds and packing remaining at 6 weeks. Non-prametric tests were used for presence of mucosal inflammation, effusion and tympanic membrane perforation. Results ABR threshold changes from baseline were minor and comparable between the Merogel group and the control group. Threshold change was higher in the Gelfoam group. This difference was seen in each frequency tested at each time interval (all p<0.05). Gross analysis showed 1) Mucosal inflammation higher in the Gelfoam group (p<0.05), 2) Effusions were higher in the Gelfoam group but the difference was not significant (p=0.07), 3) Tympanic membrane perforation was equally rare between groups (p>0.05), 4) Unabsorbed packing was higher in the Gelfoam group (p<0.05); little Merogel was detectable at time of sacrifice. Conclusion Middle ear healing after surgery occurred similarly in the control group and the Merogel group. In contrast, the Gelfoam group demonstrated greater perturbation of hearing and a greater inflammatory reaction. Significance These results support Merogel as an alternative to Gelfoam in middle ear packing after otologic surgery. Support Research grant from Medtronic ENT.

scholarly journals Closure of small perforation in tympanic membrane by use of fat plug

2020 ◽  
Vol 6 (9) ◽  
pp. 1647
Author(s):  
Nehal R. Patel ◽  
Vaibhav V. Patel ◽  
Dimpal Padavi ◽  
Mayur Prajapati ◽  
Rachana M. Khokhani ◽  
...  
Keyword(s):  
Tympanic Membrane ◽  
Ossicular Chain ◽  
Tympanic Membrane Perforation ◽  
Major Surgery ◽  
Graft Material ◽  
Middle Ear Mucosa ◽  
Suppurative Otitis Media ◽  
Membrane Perforation ◽  
Conventional Myringoplasty ◽  
Small Perforation

<p class="abstract"><strong>Background: </strong>Chronic suppurative otitis media presents mostly with ear discharge and associated decreased hearing. Tympanoplasty is the established surgery for tympanic membrane perforation. Most commonly used graft material for tympanoplasty is temporalis fascia. Others are fascia lata, tragal perichondrium, tragal cartilage, fat. The objective of the study was to compare the graft taken up and hearing improvement following myringoplasty with use of fat.</p><p class="abstract"><strong>Methods:</strong> Patients of CSOM aged 10 to 65 years old with small central perforation which is dry for at least 3 weeks with normal middle ear mucosa and intact ossicular chain with mild conductive hearing loss. The present study was carried out in Ear, neck and throat (ENT) Department of SCL hospital, Ahmedabad from July 2016 till September 2018 and 25 patients were randomly selected fulfilling the above criteria.</p><p class="abstract"><strong>Result: </strong>The choice of graft affects not only the outcome of surgery, but also determines the complexity of the procedure and the time taken for the same. Study proves that fat is also a one of the good grafting material which is easily available and keep to prevent from major surgery. The results have been quite encouraging.</p><p class="abstract"><strong>Conclusion: </strong>Study proves that fat is also a one of the good grafting material which is easily available and keep to prevent from major surgery. An added advantage of this technique was the excellent post-operative quality of life of the operated patients, assessed in terms of the chronic ear survey and evident by the absence of the usual post-operative complaints following a conventional myringoplasty.</p>

Ossicular Chain Reconstruction in a Developing Country

2018 ◽  
Vol 127 (5) ◽  
pp. 306-311 ◽  
Author(s):  
Es-Hak Bedri ◽  
Miriam Redleaf
Keyword(s):  
Tympanic Membrane ◽  
Developing Country ◽  
Middle Ear ◽  
Granulation Tissue ◽  
Ossicular Chain ◽  
Single Stage ◽  
Limited Resources ◽  
Closure Rate ◽  
Average Improvement ◽  
Ossicular Chain Reconstruction

Objectives: In Ethiopia, 2-stage operations with middle ear prostheses are economically unfavorable. We hypothesized that single-stage autologous ossiculoplasty results in acceptable tympanic membrane (TM) and hearing improvements in a setting of limited resources. Methods: One hundred eighty-eight patients (197 ears) who underwent 1-stage autologous ossiculoplasty for ossicular dysfunction are presented. All but 14 of these ears also had perforations of the TM. Conditions of the middle ear were granulation tissue, ossicular disruption only, tympanosclerosis, and cholesteatoma. Reconstructions of the ossicular chain were performed with autologous ossicles only. Results: The closure rate of TM perforations was 95%. Preoperative air bone gaps were 27 to 60 dB (mean [SD] = 44 [7] dB); postoperative air bone gaps were 0 to 50 dB (average [SD] = 23 [10] dB), for an average improvement of 21 dB across all reconstruction types ( P < .001). The largest favorable changes in air bone gaps were with incus and malleus columellas from the footplate to the TM (33 and 23 dB, respectively) ( P < .001). No patient had worsening of sensorineural hearing levels or extrusion of the reconstructed ossicles. Conclusion: Autologous ossiculoplasty performed well in this setting. Acceptable TM closure rates and improvement of air bone gaps were seen in 1-stage operations without the use of prostheses.

Common drugs used in ENT

2009 ◽  
pp. 347-350
Author(s):  
Rogan Corbridge ◽  
Nicholas Steventon
Keyword(s):  
Inner Ear ◽  
Tympanic Membrane ◽  
Middle Ear ◽  
Otitis Externa ◽  
Round Window ◽  
Acid Reflux ◽  
Tympanic Membrane Perforation ◽  
Active Infection ◽  
Middle Ear Mucosa ◽  
Membrane Perforation

Drugs used in the ear 348 Drugs used in the nose 349 Drugs used in the treatment of acid reflux 350 This group of drugs is widely used for the treatment of otitis externa. Otitis externa 2 drops tds for 10 days Presence of grommet or tympanic membrane perforation due to aminoglycoside ototoxicity in the inner ear. Risk thought to be low in the presence of active infection where the middle-ear mucosa is swollen and the antibiotic is unlikely to reach the inner ear via the round window...

scholarly journals Correlation of Site and Size of Tympanic Membrane Perforation and Middle Ear Air Space Volume with Magnitude of Hearing Loss

2019 ◽  
Vol 02 (01) ◽  
pp. 10-15
Author(s):  
Ramandeep Singh Virk ◽  
Krishan Kudawla ◽  
Sandeep Bansal ◽  
Ramya Rathod ◽  
Samarendra Behera
Keyword(s):  
Hearing Loss ◽  
Tympanic Membrane ◽  
Middle Ear ◽  
Tympanic Membrane Perforation ◽  
Tympanic Membrane Perforations ◽  
Air Space ◽  
Membrane Perforation ◽  
Volume Group ◽  
Space Volume ◽  
Lower Frequencies

Abstract Introduction The effects of tympanic membrane perforations on middle ear sound transmission are not well characterized, largely because ears with perforations typically have additional pathological changes. It has been established that the larger the perforation, the greater is the hearing loss (HL). Aim This study aimed to correlate the location and size of tympanic membrane perforation and middle ear air space volume with the magnitude of HL in patients with tubotympanic or inactive mucosal type of chronic otitis media (COM). Materials and Methods A prospective clinical study of patients with tympanic membrane perforations due to COM and without any other ear disease and who attended the Otolaryngology services at our institute between July 2010 and December 2011 was conducted. A total of 300 ears were evaluated by performing otoendoscopy, followed by photo documentation and audiological investigations (pure-tone audiometry and tympanometry). Tympanic membrane perforations were categorized based on their size and location, and the mean air-bone (AB) gap between the various types of perforations was compared and statistically analyzed with significance level of p < 0.05. Results Out of 300 ears, maximum number of ears (n = 124, 41.3%) had large-sized perforations (> 30 mm2) that had a maximum mean AB gap of 26.43 dB, and minimum number of ears (n = 60, 20%) had small-sized perforations (0–9 mm2) that had minimum mean AB gap of 9.12 dB. The remaining were medium-sized perforations that had mean AB gap of 16.13 dB. Depending on the location, maximum were central perforations (n = 198, 66%) and minimum were anterosuperior (AS) perforations (n = 9, 3%). Based on the middle ear volume on tympanometry, maximum ears were of low-volume group (n = 246, 92%) that had larger mean AB gap of 19.96 dB HL when compared with the high-volume group (n = 24, 8%) with 11.80 dB HL. AB gap was maximum at lower frequencies and decreased with increase in frequencies except at 4,000 Hz, that is, 56.9 dB HL at 250 Hz, 42.6 at 500 Hz, 41.5 at 1,000 Hz, 32.4 at 2,000 Hz, and 49.5 at 4,000 Hz. Conclusion HL increases as the area of tympanic membrane perforation increases. There is an inverse relationship between HL and middle ear air space volume. Comparing the small-sized perforations at different sites with the middle ear volume being low, it was found that posterosuperior (PS) perforations had 4 to 7 dB greater HL than AS and anteroinferior (AI). However, the relationship was statistically insignificant. The phase cancellation effect of round window causing greater HL in posteroinferior (PI) perforations does not exist in small- and medium-sized perforations. HL is greater at lower frequencies and less at higher frequencies.

Ototoxicity after use of neomycin eardrops is unrelated to A1555G point mutation in mitochondrial DNA

2004 ◽  
Vol 118 (7) ◽  
pp. 546-550 ◽  
Author(s):  
Tatsuya Yamasoba ◽  
Katsunori Tsukuda
Keyword(s):  
Mitochondrial Dna ◽  
Tympanic Membrane ◽  
Point Mutation ◽  
Middle Ear ◽  
Dna Analysis ◽  
Tympanic Membrane Perforation ◽  
Mitochondrial Dna Analysis ◽  
Membrane Perforation ◽  
Inner Ear Damage ◽  
Ear Drops

Ear drops containing neomycin only rarely cause ototoxicity. The authors report on three patients with a tympanic membrane perforation who developed severe ototoxicity after use of eardrops containing 0.35 per cent neomycin. Mitochondrial DNA analysis revealed that there was no A1555G point mutation in these patients. This finding indicates that application of low concentration neomycin to the middle ear can cause severe inner ear damage even in humans who are not hyper-susceptible to aminoglycosides.

scholarly journals Study on the Prosthesis Structural Design and Vibration Characteristics Based on the Conduction Effect of Human Middle Ear

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Wu Ren ◽  
Huijuan Yan ◽  
Yi Yu ◽  
Jinghong Ren ◽  
Jinlong Chang ◽  
...  
Keyword(s):  
Frequency Response ◽  
Inner Ear ◽  
Tympanic Membrane ◽  
Middle Ear ◽  
Transmission Function ◽  
Ossicular Chain ◽  
Sound Signal ◽  
Sound Perception ◽  
Response Characteristics ◽  
Middle Ear Prosthesis

As a bridge from the sound signal in the air to the sound perception of the inner ear auditory receptor, the tympanic membrane and ossicular chain of the middle ear transform the sound signal in the outer ear through two gas-solid and solid-liquid conversions. In addition, through the lever principle formed by three auditory ossicle structure, the sound was concentrated and amplified to the inner ear. However, the sound transmission function of the middle ear will be decreased by disease, genetic, or trauma. Hence, using middle ear prosthesis to replace the damaged ossicles can restore the conduction function. The function realization of middle ear prosthesis depends on the vibration response of the prosthesis from the tympanic membrane to the stapes plate on the human auditory perception frequency, which is affected by the way the prosthesis combined with the tympanic membrane, the material, and the geometric shape. In this study, reasonable prosthetic structures had been designed for different types of ossicular chain injuries, and the frequency response characteristics were analyzed by the finite element method then. Moreover, in order to achieve better vibration frequency response, a ball structure was designed in the prosthesis to simulate its amplification function. The results showed that the middle ear prostheses constructed by different injury types can effectively transfer vibration energy. In particular, the first- and second-order resonant frequencies and response amplitudes are close to each other when ball structure models of different materials are added. Instead, the resonance frequency of the third stage formed by aluminum alloy ball materials is larger than that of the other two, which showed good response features.

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