[Aberrant internal carotid artery in the middle ear: a case report]

Aberrant course of the internal carotid artery within the middle ear is a rare condition. Surgical interventions following clinical or radiological misinterpretations may lead to fatal complications. A 23-year-old female patient presented with a hearing impairment of 10-month duration. On otoscopic examination, the left tympanic membrane was intact, but there was a pulsatile lesion in the tympanic cavity, synchronous with the heartbeats. Pure-tone audiometric examination of the left ear showed a unilateral mixed hearing loss, especially in low frequencies. Computed tomography showed protrusion of the internal carotid artery into the middle ear from the lateral and superior aspects of the cochlea. Magnetic resonance imaging and MR-angiography showed a left-sided deviation of the left internal carotid artery near the cochlea, associated with a filling defect. The caliber of the left internal carotid artery was narrower than the right one in the middle ear, and its proximal part was thinner. A diagnosis of aberrant internal carotid artery was made.

[The high position of the jugular bulb in children]

INTRODUCTION

Variations of the vascular structures related to the temporal bone may cause important problems in diagnosis, treatment planing and surgery. A high jugular bulb is not an uncommon anomaly. It has been reported to occur in up to 6% of temporal bones. A high jugular bulb is often discovered as an asymptomatic, incidental finding. Case reports indicate that abnormal location of the jugular bulb may be the cause of some audiological problems. Conductive hearing loss in association with this anomaly may occur, but has been reported infrequently in the literature.

MATERIAL AND METHODS

Two children with high jugular bulb are presented.

RESULTS

One boy presented as a profuse bleeding from the right middle ear space after raising a tympanomeatal flap during surgery due to bilateral retraction pockets. Another one had unilateral conductive hearing loss with abberant, bluish mass seen behind tympanic membrane. CT revealed high position of jugular bulb in those patients. Results of otoscopic, audiological and radiological examinations are presented.

CONCLUSION

ENT specialists and otologic surgeons should be aware of this entity to perform differential diagnosis of conductive hearing loss and avoid penetration of the jugular bulb during surgery.

Msx1 and Dlx5 act independently in development of craniofacial skeleton, but converge on the regulation of Bmp signaling in palate formation

Msx and Dlx homeoproteins control the morphogenesis and organization of craniofacial skeletal structures, specifically those derived from the pharyngeal arches. In vitro Msx and Dlx proteins have opposing transcriptional properties and form heterodimeric complexes via their homeodomain with reciprocal functional repression. In this report we examine the skeletal phenotype of Msx1; Dlx5 double knock-out (DKO) mice in relationship with their expression territories during craniofacial development. Co-expression of Dlx5 and Msx1 is only observed in embryonic tissues in which these genes have independent functions, and thus direct protein interactions are unlikely to control morphogenesis of the cranium. The DKO craniofacial phenotypes indicate a complex interplay between these genes, acting independently (mandible and middle ear), synergistically (deposition of bone tissue) or converging on the same morphogenetic process (palate growth and closure). In the latter case, the absence of Dlx5 rescues in part the Msx1-dependent defects in palate growth and elevation. At the basis of this effect, our data implicate the Bmp (Bmp7, Bmp4)/Bmp antagonist (Follistatin) signal: in the Dlx5(-/-) palate changes in the expression level of Bmp7 and Follistatin counteract the reduced Bmp4 expression. These results highlight the importance of precise spatial and temporal regulation of the Bmp/Bmp antagonist system during palate closure.

[Clinical classification and relationship with conductive deafness of congenital middle ear malformations]

OBJECTIVE

To investigate the clinical classification and relationship with conductive deafness of congenital middle ear malformations.

METHODS

From 1995 to 2004, 64 patients (82 ears) with single congenital middle ear malformations were operated in the ENT department of the General Hospital of Chinese People's Liberation Army. According to the histology and embryology of middle ear and the findings of surgical exploration, the clinical classification was performed. Statistical analysis was used to judge the differences of hearing loss in different type of congenital middle ear malformations.

RESULTS

According to the embryologic development of the structures in middle ear, congenital middle ear malformations were classified 4 types. Type A: congenital ossicular chain anomalies; type B: congenital fusion of stapes; type C: congenital hypoplasia or atresia of oval/round widows. Hearing loss of three types on language frequency have no obvious difference (P = 0.1617), but there were statistical difference on high frequency ( > 2 kHz) between type A with type B and type C (P <0.05). Furthermore, descension of bone conduction and mixed deafness were familiar in type B and C.

CONCLUSIONS

According to embryologic development, it was rational that congenital middle ear malformations were classed 3 types mentioned above. Hearing loss due to middle ear malformations could be distinguished by descension of bone conduction and air conduction on high frequency ( >2 kHz).

Unusual extension of the first branchial cleft anomaly

First branchial cleft is the only branchial structure that persists as the external ear canal, while all other clefts are resorbed. Incomplete obliteration and the degree of closure cause the varied types of first branchial cleft anomalies. They were classified based on the anatomical and histological features. We present an unusual type of first branchial cleft anomaly involving the external auditory canal, the middle ear and the nasopharynx through the eustachian tube.

Dysmorphism of the middle ear: case report

Although there are numerous publications in the literature describing the wide range of diagnosis, classifications and treatment of malformations of the hearing apparatus, even more variations can be found in clinical practice. Indeed, each individual case is unique as far as concerns pathogenesis, clinical course and treatment. The case reported herein describes a 12-year-old boy affected by cranio-facial dysmorphism and monolateral conductive hearing loss in the right ear: followed from radiological diagnosis--carried out to study a malformation of the ear pinna--to surgical treatment.

Vestibulotomy above a severely displaced facial nerve

CONCLUSIONS

Vestibulotomy above a severely displaced facial nerve represents a new surgical approach to achieve serviceable hearing. The lack of facial nerve injury and the potential for hearing restoration make this procedure feasible in patients who would otherwise be marginal or poor surgical candidates.

OBJECTIVE

To investigate the feasibility of vestibulotomy above a severely displaced facial nerve.

MATERIAL AND METHODS

Eight patients with severe congenital conductive hearing loss underwent vestibulotomy above a severely displaced facial nerve and hearing reconstruction between January 2000 and January 2002. All patients had congenital middle ear deformities. The facial nerves overhung and concealed the oval window niche or lay inferior to the oval window. The facial nerves were transposed in order to reach the oval window niche in four of eight cases.

RESULTS

Hearing gain was 15 dB in 2 ears, 16-25 dB in 3 and > 26 dB in 3. There were no cases of postoperative facial paresis.

Facial canal anatomy in patients with mandibulofacial dysostosis: comparison with respect to the severities of microtia and middle ear deformity

OBJECTIVE

To study the difference in the facial canal anatomy in terms of the severity of microtia and deformity of the middle ear in patients with mandibulofacial dysostosis using high-resolution computed tomography.

STUDY DESIGN

Retrospective analyses.

SETTING

The study was carried out at the Department of Otorhinolaryngology, University of Tokyo, Tokyo, Japan.

PATIENTS

Thirty-six ears of 18 patients with mandibulofacial dysostosis were examined by high-resolution computed tomography. These ears were graded based on the Marx classification and Jahrsdoerfer scoring systems.

MAIN OUTCOME MEASURES

The high-resolution computed tomography findings and age distribution of each group were compared with those of other groups by multiple comparison using Tukey's honestly significant difference test.

RESULTS

The course of the facial nerve was not significantly different in terms of the severity of microtia and deformity of the middle ear. The bony cochlea in the patients with mandibulofacial dysostosis was displaced by a mean value of 2 mm more anteriorly and a mean value of 0.7 mm shallower than that in the cases with normal auricles.

CONCLUSION

The facial nerve of patients with mandibulofacial dysostosis is displaced more anterolaterally than that of the cases with normal auricles; however, the auricle anomaly is not severe.

Otologic and audiologic features of Nager acrofacial dysostosis

OBJECTIVE

To describe the otologic and audiologic characteristics of pediatric patients with Nager acrofacial dysostosis.

DESIGN

Retrospective case series.

SETTING

Multidisciplinary clinic in a tertiary care children's hospital.

SUBJECTS

Patients less than 18 years of age with Nager acrofacial dysostosis.

METHODS

Nager syndrome is a mandibulofacial dysostosis associated with preaxial limb abnormalities and multiple craniofacial anomalies. Ten patients with Nager syndrome were reviewed. Relevant literature, 1966 to the present, was reviewed with the assistance of Medline.

RESULTS

External and middle ear abnormalities are common in Nager syndrome. All non-atretic ears had significant difficulty with otitis media, requiring an average of two sets of tympanostomy tubes. Cholesteatoma was diagnosed in one patient. Pure conductive hearing loss was identified in eight patients with mixed hearing loss noted in two patients. Conductive hearing loss greater than 30 dB HL was noted in 90% (9/10) of patients, with 40% (4/10) having 55-70 dB HL loss. Although amplification was effective, results of surgical interventions to correct conductive hearing loss were inconsistent. Two patients with mixed hearing loss developed the sensorineural component in later childhood, indicating that progressive or fluctuating sensorineural hearing loss is also possible in this population.

CONCLUSIONS

Pediatric patients with Nager acrofacial dysostosis exhibit conductive hearing loss due to middle and external ear pathology. Prolonged ventilation of the middle ear via tympanostomy tubes and amplification with hearing aids are often required. Some patients also demonstrate mixed hearing loss that may be progressive and should be monitored carefully. Early and aggressive management in a multidisciplinary team approach is recommended.

Optical and tomographic imaging of a middle ear malformation in the bullfrog (Rana catesbeiana)

Using a combination of in vivo computerized tomography and histological staining, a middle ear anomaly in two wild-caught American bullfrogs (Rana catesbeiana) is characterized. In these animals, the tympanic membrane, extrastapes, and pars media (shaft) of the stapes are absent on one side of the head, with the other side exhibiting normal morphology. The pars interna (footplate) of the stapes and the operculum are present in their normal positions at the entrance of the otic capsule on both the affected and unaffected sides. The pattern of deformity suggests a partial failure of development of tympanic pathway tissues, but with a preservation of the opercularis pathway. While a definitive proximate cause of the condition could not be determined, the anomalies show similarities to developmental defects in mammalian middle ear formation.

Murine teratology of fluconazole: evaluation of developmental phase specificity and dose dependence

The potential of in utero exposure to fluconazole to initiate teratogenesis was analyzed in ICR (CD-1) mice. Developmental phase specificity was determined by treating mice with single oral doses of 700 mg/kg on gestational day 8, 9, 10, 11, or 12. Control animals received vehicle on gestational days 8-12. Gestational day 10 was identified as the phase of maximal sensitivity for induction of cleft palate, the predominant teratogenic effect induced by fluconazole, with 50% of fetuses exposed on this developmental phase being affected. After treatments on gestational day 8, 9, 11, or 12, cleft palate occurred with lower frequencies: 12, 21, 28.7, and 2.7%, respectively. Examination of skeletal morphology revealed anomalies of the middle ear apparatus in 15% of the fetuses that were exposed on gestational day 8. Dysmorphic tympanic ring and absence of the incus were the more common ear anomalies recorded. Reduced humeral length was noted in 22% of fetuses that were exposed on gestational day 10. Dose-response relationship was investigated by treating animals with 0 (vehicle), 87.5, 175, or 350 mg/kg on gestational day 10, coincident with the phase of peak teratogenic sensitivity. Besides showing that fluconazole operates under a strict dose-response mechanism, the study identified 175 mg/kg as the lowest observed adverse effect level for cleft palate induction, with 7.6% of the exposed fetuses being affected.

Correlation between microtia and temporal bone malformation evaluated using grading systems

OBJECTIVE

To evaluate the relationships between temporal bone abnormalities and the severity of microtia in Japanese patients using objective grading systems.

DESIGN

Retrospective case series study conducted between 1992 and 2003.

SETTING

Academic, tertiary care, referral medical center.

PATIENTS

One hundred forty-two ears of 109 Japanese patients (85 male and 24 female patients; mean age, 12.8 years [range, 2-36 years]) with microtia.

MAIN OUTCOME MEASURES

The severity of microtia was classified according to Marx classification. Developmental abnormalities of the temporal bone were evaluated by a computed tomographic (CT) scoring system modified after the system used by Jahrsdoerfer and colleagues, using high-resolution CT scans of the temporal bone. Correlations between the scores obtained from these 2 grading systems were evaluated using a nonparametric statistical method.

RESULTS

Male preponderance and incidence of bilateral cases of approximately 30% were observed in our Japanese patients with microtia. There was no significant difference in the severity of microtia between unilateral and bilateral cases. The mean +/- SEM total points in the CT scoring system (full marks, 10) was 7.9 +/- 0.4 for grade I microtia, 6.6 +/- 0.6 for grade II, and 6.4 +/- 0.3 for grade III; the total points correlated inversely with the microtia grade. Development of the auricle correlated significantly with aeration in the middle ear spaces but not with ossicular development or formation of the oval/round windows. Proportion of acceptable surgical candidates according to the CT scoring system (>5 points) was 79% for grade I microtia, 52% for grade II microtia, and 65% for grade III microtia.

CONCLUSION

The principle "the better developed the auricle, the better developed middle ear" was confirmed in Japanese patients with microtia; however, even with grade II/III microtia, more than half of the patients were considered suitable for atresia surgery.

[Long-term surgical results for congenital aural atresia and hearing reconstruction]

OBJECTIVE

To evaluate the stability of hearing results and complications in long-term following-up who underwent reconstruction surgery.

METHODS

Six hundreds and seventy five cases (700 ears) of congenital aural atresia were reviewed from January 1984 to January 2001 at the Department of Otorhinolaryngology Head and Neck Surgery, Tongren hospital. Except 40 ears undone hearing reconstruction, 635 cases (660 ears) underwent long-term following-up for 3 to 19 years, with an average of 7.9 years.

RESULTS

Stenosis and recurrent infection of the external auditory canal (EAC) were the most frequent complications. Stenosis was seen in 120 ears, and 2 ears re-atresia, with an incidence of 18.48% (122/660). Recurrent infection of the cavity and canal skin happened in 6 ears. Closure of the air-bone gap (ABG) post-operation were gained in all cases, and ABG gains 20 dB or more occurred in 512 ears (77.57%), but 30 dB or more in 231 ears (35%). Following-up results: Stable hearing results gained in 450 ears over the length of following-up; the hearing worsened than that of 3 weeks postoperatively occurred in 160 ears, including 2 ears with sensorineural hearing loss. Hearing deteriorated more than 20 dB happened in 35 ears, and 10-15 dB in others cases but still be improved compared with that of preoperation.

CONCLUSIONS

Atresiaplasty surgery in individuals with congenital aural atresia can yield reliable, lasting hearing results in 68.2% (450/660), with a low incidence of complications; the initial improved hearing deteriorated gradually over the first 6 months post-operation, which are related with the stenosis and infection of canal. Cavity adhesion, bony EAC re-growth, ossicular chain re-fixation or displace may affect the hearing results in some cases. Even unilateral aural atresia may benefit from the reconstruction surgery and achieve serviceable hearing results.

Inner Ear Abnormalities in Patients with Goldenhar Syndrome

OBJECTIVE

The objective of this study is to investigate the inner ear malformations in patients with Goldenhar syndrome and to hypothesize the potential embryopathogenesis of these malformations.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Fourteen patients with Goldenhar syndrome.

INTERVENTIONS

Each patient underwent hearing tests and high-resolution computed tomography (CT) of the temporal bone. In six patients, magnetic resonance imaging of the temporal bone also was performed.

RESULTS

Among the 14 patients with Goldenhar syndrome, 13 had outer and middle ear anomalies and 5 (36%) had inner ear malformations, including one case of common cavity.

CONCLUSIONS

Our observations regarding inner ear anomalies in Goldenhar syndrome correlate with the reported cases in the literature and may help to hypothesize the embryological origin of these malformations, which can caused by an early developmental arrest in the fourth gestational week. Specialists evaluating patients with Goldenhar syndrome should be aware of the possibility of inner ear malformations, which could be diagnosed earlier with appropriate imaging studies.

Hyrtl's fissure: a case of spontaneous cerebrospinal fluid otorrhea

Spontaneous CSF otorrhea is a relatively rare entity. Adequate diagnosis and treatment are needed to avoid life-threatening complications such as meningitis. Because diagnosis is based on CT findings, identification of the different pathways of congenital fistulas requires detailed knowledge of embryology and anatomy. The facial canal, petromastoid canal, and tympanomeningeal (Hyrtl's) fissure can be responsible for CSF fluid otorrhea in the absence of any abnormality of the adjacent membranous labyrinth. We report the first documented and imaging case of Hyrtl's fissure and its treatment.

Surgical considerations in cochlear implantation in children and adults: a review of 342 cases in Vienna

CONCLUSIONS

Our data represent the experience of the largest cochlear implant program in Austria. In conclusion, cochlear implantation is a safe procedure, associated with a low rate of intra- and postoperative complications. Nevertheless, patients should be informed about possible problems and especially about the risk of a reoperation due to device failure.

OBJECTIVES

To evaluate the cause of deafness, the intraoperative findings and the complication rate for all cochlear implant operations performed consecutively between 1994 and 2003 at Vienna General Hospital.

MATERIAL AND METHODS

Including all surgeries for bilateral implantation and revision, a series of 342 operations performed on 164 adults (age range 14.5-81 years; mean age 50.79 years) and 128 children (age range 0.75-14 years; mean age 5.00 years) was retrospectively analyzed.

RESULTS

The etiology of deafness was predominantly congenital or progressive (66.89%). The routine mastoidectomy approach was chosen in 300 patients (87.72%) and the suprameatal approach in 42 (12.28%). Intraoperatively, 4 children (2.53%) had a cerebrospinal fluid fistula and 35 patients (10.23%) showed cochlear ossification. Three adults (1.63%) and two children (1.27%) had facial nerves with an aberrant course. The overall complication rate was 12.2%, the rate of major complications was 4.97% and the rate of minor complications was 4.09%. There were no cases of either postoperative meningitis or facial nerve palsy. Both flap necrosis and electrode dislocation occurred in one adult patient (0.54%), but in none of the children. Formation of cholesteatoma was found in one adult (0.54%) and one child (0.63%). The rate of device failure was 7.07% for adults and 13.92% for children.

[Congenital external and middle ear malformation-with 62 ears report]

OBJECTIVE

To determine the relationship between external ear malformation and middle ear abnormality, and also the results of surgical treatment.

METHOD

Fifty-two cases with external ear malformation (62 ears) was dividied into two groups:the minor group and severe group. All the patients received surgical treatment, 48 ears by transmastoid approach and 14 ears by "direct entrance" approach.

RESULT

The middle ear abnormality was minor in minor group,and severe in the patients with severe external ear malformation. In 93.5% cases the hearing threshold improved more than 15 dB in 3 months after operation, and reduce to 85.5% in 3 years follow up.

CONCLUSION

The middle ear malformation is corresponding to external ear malformation. The effect of surgical treatment is different according to the degree of malformation and surgical complication.

Combined Microtia and Aural Atresia: Issues in Cochlear Implantation

OBJECTIVES

This article presents the first report of cochlear implantation in a patient with congenital aural atresia, microtia, dysplastic cochlea and internal auditory canals, and bilateral profound sensorineural hearing loss (HL). This rare combination requires special management considerations. Preoperative issues include thorough evaluation of computed tomography and magnetic resonance imaging to determine favorable anatomy, cochlear implantation candidacy, and surgical planning. Intraoperative concerns include incision placement, surgical approach to the middle ear, and abnormal facial nerve anatomy. Postoperative use of a special headset combining a microphone and transmitter coil is required.

STUDY DESIGN

Case report and literature review.

METHODS

The patient's chart was reviewed for diagnostic studies, operative strategy, and postoperative auditory stimulation and testing. A literature review was performed.

RESULTS

A 2-year-old male presented with bilateral aural atresia, microtia, and profound sensorineural HL. Imaging studies revealed multiple abnormalities of the cochlea, vestibule, and internal auditory canal, all of which were more favorable on the right side. An incision was designed to accommodate future microtia repair. The cochlear implant was placed without difficulty by way of a facial recess approach to the middle ear. Postoperative results include the detection of Ling sounds and voices in the environment as well as the ability to locate sounds.

CONCLUSIONS

This is the first report of cochlear implantation in a patient with bilateral aural atresia, microtia, and profound sensorineural HL in conjunction with multiple inner ear abnormalities. Close collaboration among the otologist, neuroradiologist, and plastic surgeon is essential to coordinate surgical management and optimize cosmetic and functional outcomes in this unique population.

[Combined middle and inner ear abnormality: report of a case]

Congenital anomalies of the middle ear associated to anomalies of the inner ear are rarely described. Our case displays a malformation due to an association of congenital absence of the round window and aplasia of the semi-circular canals, causing conductive hearing loss. First diagnosis was a congenital atresia isolated of the round window, related to a previous surgical exploration. We tried a novel technique designed to restore the function of the round window. Labyrinthine anomalies prevented a good outcome. This kind of malformative association could be due to the complexity of early genetic control of ear development. Attentive analysis of imaging should be performed before middle ear surgery to determine the presence of inner ear anomalies which are quite frequent and which would limit its usefulness.

[Clinical study of congenital middle ear malformations]

OBJECTIVE

To search into the diagnosis and treatment of congenital malformation of middle ear.

METHOD

Nine patients were involved in our study, exploratory tympanotomy was undergone in all patients (eleven ears) and eight ears were reconstructed the ossicular chain.

RESULT

Exploratory tympanotomy showed a variety of abnomalities of the middle ear which were difficult to identify preoperatively, despite the modern imaging techniques. Stapedectomy using a wire prosthesis with an oval window tissue graft to prevent a perilymphatic leak was carried out in four ears, fenestration of vestibule with stapes prosthesis in two ears, removing the fibrotic strand around the incudostapedial joint in one ear, TORP (Total replacement prosthesis) were used in one ear, gain in hearing thresholds was obtained without severe complications occurrence.

CONCLUSION

Exploratory tympanotomy is essential to identify congenital conductive hearing loss and wire prosthesis may provide a potential way for reconstruction of ossicular chain.

Histopathological basis of hearing impairment in Wolf-Hirschhorn syndrome

OBJECTIVES/HYPOTHESIS

To perform histological examination of temporal bones acquired from an infant with Wolf-Hirschhorn syndrome with an emphasis on identifying abnormalities that might be responsible for hearing impairment in this disorder.

STUDY DESIGN

Retrospective case review.

METHODS

Temporal bones were taken at autopsy from a 10-month-old infant with Wolf-Hirschhorn syndrome. The right-side temporal bone was studied by microdissection. The middle ear was examined, and the inner ear sensory organs dissected for study by light microscopy. The left-side temporal bone was embedded in celloidin, and sections were cut for microscopic examination.

RESULTS

Chronic otitis media was observed in both ears. Inflammation, effusion, and adhesions were present in the middle ear space. The malleus was malformed, and the chorda tympani nerve was found to pass through the bone of the malleus bilaterally. There was an area of sharply defined outer hair cell loss in the lower basal turn of the right-side organ of Corti, and defects were noted in the bone of the apical osseous spiral lamina in both cochleae.

CONCLUSION

In addition to the presence of otitis media, the likelihood of congenital abnormalities of the middle and inner ear should be considered in the assessment of patients with Wolf-Hirschhorn syndrome with hearing impairment.

3D-Darstellung des Mittelohres mittels computergestützter Nachverarbeitung helikaler Mehrschicht-CT-Daten

Post-processing of CT-data allows non-invasive 3D-Visualisation of the middle ear for diagnosis and surgical planning. In this study different post-processing techniques and the clinical application of a 3D-postprocessing algorithm in a large number of patients are presented. 20 normal patients, 6 dissected temporal bones and 213 patients with suspected middle ear pathology were examined using a low-dosage Multi-Slice CT protocol. Virtual endoscopic views of the middle ear and 3D-images of the ossicles were generated using a standardised algorithm. Evaluation of the image quality was performed. The virtual views of the dissected temporal bones were compared to real views. In 32 patients high-quality 3D-models of the individual anatomical structures were generated and displayed using different visualisation techniques. The standardised and evaluated method enabled visualisation of the normal middle ear anatomy. Assessment of different pathologies, especially malformation, trauma, implants and postoperative alterations, was facilitated. The high-quality 3D-models allowed precise imaging of the anatomical structures. 3D-Visualisation of the middle ear using CT-data is beneficial for radiological diagnosis and surgical planning in cases of complex middle ear pathology as a complementary examination technique.

An ENU-induced mutation in AP-2α leads to middle earand ocular defects in Doarad mice

One of the advantages of N-ethyl- N-nitrosourea (ENU)-induced mutagenesis is that, after randomly causing point mutations, a variety of alleles can be generated in genes leading to diverse phenotypes. For example, transcription factor AP-2alpha ( Tcfap2a) null homozygote mice show a large spectrum of developmental defects, among them missing middle ear bones and tympanic ring. This is the usual occurrence, where mutations causing middle ear anomalies usually coincide with other abnormalities. Using ENU-induced mutagenesis, we discovered a new dominant Tcfap2a mutant named Doarad ( Dor) that has a missense mutation in the PY motif of its transactivation domain, leading to a misshapen malleus, incus, and stapes without any other observable phenotype. Dor homozygous mice die perinatally, showing prominent abnormal facial structures and ocular defects. In vitro assays suggest that this mutation causes a "gain of function" in the transcriptional activation of AP-2alpha. These mice enable us to address more specifically the developmental role of Tcfap2a in the eye and middle ear and are the first report of a mutation in a gene specifically causing middle ear abnormalities, leading to conductive hearing loss.

Congenital Malformations of the Middle Ear with an Intact External Ear: A Review of 38 Cases

In patients with middle ear malformations, one can expect an improvement in hearing following ear surgery. Thus, it is crucial for the ear surgeon to have an increased awareness of this disease. For a better understanding of this condition, 38 patients who underwent ear surgery were studied. All patients had congenital ossicular malformations but with an intact external ear. On the basis of our intra-operative observations, 15 cases were assigned to group A (single malformation) and 23 cases to group B (multiple malformations). The pre-operative air-conduction threshold in group B patients was higher than that in group A. Pre-operatively in group A 2 out of 20 ears had mild, 17 had moderate and 1 had severe hearing loss (HL). In group B, out of 25 ears, 3 had mild, 13 had moderate and 9 had severe HL. Post-operatively in group A, 2 had normal hearing, 16 had mild, 2 had moderate and none had severe HL. In group B, postoperatively 1 had normal hearing, 18 had mild, 4 moderate and 2 severe HL. Therefore, in patients with multiple middle ear malformations, the surgeon should know that the prospect of an improvement in the hearing threshold is rather low even after surgical reconstruction.