[Numerical study on the effect of middle ear malformations on energy absorbance].

In order to study the effect of middle ear malformations on energy absorbance, we constructed a mechanical model that can simulate the energy absorbance of the human ear based on our previous human ear finite element model. The validation of this model was confirmed by two sets of experimental data. Based on this model, three common types of middle ear malformations, i. e. incudostapedial joint defect, incus fixation and malleus fixation, and stapes fixation, were simulated by changing the structure and material properties of the corresponding tissue. Then, the effect of these three common types of middle ear malformations on energy absorbance was investigated by comparing the corresponding energy absorbance. The results showed that the incudostapedial joint defect significantly increased the energy absorbance near 1 000 Hz. The incus fixation and malleus fixation dramatically reduced the energy absorbance in the low frequency, which made the energy absorbance less than 10% at frequencies lower than 1 000 Hz. At the same time, the peak of energy absorbance shifted to the higher frequency. These two kinds of middle ear malformations had obvious characteristics in the wideband acoustic immittance test. In contrast, the stapes fixation only reduced the energy absorbance in the low frequency and increased energy absorbance in the middle frequency slightly, which had no obvious characteristic in the wideband acoustic immittance test. These results provide a theoretical reference for the wideband acoustic immittance diagnosis of middle ear malformations in clinic.

Treacher Collins syndrome: A novel TCOF1 mutation and monopodial stapes.

Treacher Collins syndrome (TCS: OMIM 154500) is an autosomal dominant craniofacial disorder belonging to the heterogeneous group of mandibulofacial dysostoses. OBJECTIVE: To investigate four Treacher Collins syndrome patients of the Sgaw Karen family living in Thailand. METHOD: Clinical examination, hearing tests, lateral cephalometric analyses, Computed tomography, whole exome sequencing and Sanger direct sequencing were performed. RESULTS: All of the patients affected with Treacher Collins syndrome carried a novel TCOF1 mutation (c.4138_4142del; p.Lys1380GlufsTer12), but clinically they did not have the typical facial gestalt of Treacher Collins syndrome, which includes downward-slanting palpebral fissures, colobomas of the lower eyelids, absence of eyelashes medial to the colobomas, malformed pinnae, hypoplastic zygomatic bones and mandibular hypoplasia. Lateral cephalometric analyses identified short anterior and posterior cranial bases, and hypoplastic maxilla and mandible. Computed tomography showed fusion of malleus and incus, sclerotic mastoid, hypoplastic middle ear space with a soft tissue remnant, dehiscence of facial nerve and monopodial stapes. CONCLUSION: Treacher Collins syndrome in Sgaw Karen patients has not been previously documented. This is the first report of monopodial stapes in a TCS patient who had a TCOF1 mutation. The absence of a common facial phenotype and/or the presence of monopodial stapes may be the effects of this novel TCOF1 mutation.

Prevalence & features of inner ear malformations among children with congenital sensorineural hearing loss: A Public Cochlear Implant Centre Experience.

OBJECTIVE: To determine the prevalence and features of inner ear anomalies in children with congenital profound hearing loss who presented at our cochlear implant center based on imaging studies. METHODS: This retrospective study reviewed charts of children with congenital SNHL, who presented to Department of Otolaryngology & Auditory Implant Centre, Capital Hospital Islamabad over a period of 2 years from 1st May 2017 to 30th April 2019. These included 481 cases of both genders aged between 1 to 12 years. After gathering demographic data, audiological data, computed tomography findings of the temporal bone were analyzed. Data was analyzed using SPSS 22. RESULTS: The Inner Ear Malformations were identified in 48(10%) children including 28 (58.33%) males and 20 (41.67%) female. Most 20(41.67%) presented at >3-5 years of age followed by 19(39.58%) at 2-3 years. However, no significant association of gender (p=0.57, p=0.076) and age of presentation (p=0.344, p=0.697) for right and left ears was noted with inner ear malformations. The most common anomaly noted were CLA, CH-III and CH-II in decreasing order of frequency in both ears. CONCLUSION: The prevalence of IEM's was found to be 48(10%). Commonest anomalies noted were CLA, CH-III and CH-II. No significant association of gender and age of presentation was noted with type of anomaly in both ears.

Unilateral congenital malformations of middle ear with intact external ear: a review of 64 cases.

OBJECTIVE: To describe the operative findings and surgical results of unilateral congenital middle ear malformations with intact external ear. METHODS: A retrospective review was performed on 64 patients with unilateral congenital middle ear malformations and intact external ear who underwent exploratory tympanotomy from 2011 to 2016. Demographic data, clinical data, high-resolution computed tomography findings, audiometric data and intraoperative findings were collected. Audiological evaluations before and 6 months after surgery were analyzed in 47 patients. RESULTS: The most common malformation were mobile stapes with missing incus long process and stapes suprastructure. The air conduction pure tone average was 58.9 ± 10.5 dB HL (range 34.4-78.1 dB HL) preoperatively and 28.8 ± 10.6 dB HL (range 9.4-55.6 dB HL) postoperatively (P = 0.000). Twenty-five cases (53.2%) acquired an air conduction hearing gain exceeding 30 dB. Mean air-bone gap (ABG) was 44.5 ± 9.4 dB (range 22.5-66.4 dB HL) before surgery and 15.6 ± 9.3 dB (range 0-35.6 dB) after surgery (P = 0.000) for an average gain of 28.8 ± 11.5 dB. Thirty-four cases (72.3%) showed a postoperative ABG of less than 20 dB, 15 had an ABG within 10 dB, and 4 had 0 dB ABG after operation. No significant difference was observed for air conduction hearing gain regarding age (P = 0.261) or types of malformations (mobile stapes footplate with or without a suprastructure anomaly, P = 0.058). CONCLUSION: Unilateral congenital middle ear malformations with intact external ear can be complex and diverse. Functional ossiculoplasty for patients with unilateral congenital middle ear malformations can achieve good hearing outcomes.

Numerical study on the effect of middle ear malformations on energy absorbance / 生物医学工程学杂志

In order to study the effect of middle ear malformations on energy absorbance, we constructed a mechanical model that can simulate the energy absorbance of the human ear based on our previous human ear finite element model. The validation of this model was confirmed by two sets of experimental data. Based on this model, three common types of middle ear malformations,

Middle ear malformations in identical twins.

The majority of the congenital anomalies of middle ear are solitary and a non-hereditary. We report cases of identical twins with congenital incudo-stapedial disconnection. Case 1 was an 8-year-old girl. Hearing impairment was identified at the age of three. She was referred to our university hospital in April 2005. Pure-tone audiogram showed conductive hearing impairments. Computed tomography (CT) revealed the incudo-stapedial disconnections in both ears. The exploratory tympanotomies on the right and left ears were performed in May and July 2005, respectively. The surgical findings showed absence of the long process and presence of the lenticular process of the incus in both ears. After the reconstructions of ossicular chain, the hearing of both ears improved. Case 2 was an 11-year-old girl. The hearing impairment of the right ear was identified in May 2008. She was referred to our university hospital three months later. Pure-tone audiogram showed the conductive hearing impairment in the right ear. CT revealed the incudo-stapedial disconnection in the right ear. The surgery showed the same findings as those of case 1. Anomalies of both cases suggest that the lenticular process of the incus and the stapes originate from a common primordium.