Congenital aural atresia. A new subclassification and surgical management

OUP accepted manuscript

Congenital aural atresia refers to abnormal embryological development of the external auditory canal. The treatment of this anatomical malformation is only surgical repair. This article reports a case of unilateral congenital aural atresia, the surgical procedure performed and the post-operative findings.

Current Treatments for Congenital Aural Atresia

Congenital aural atresia is an ear malformation evident at birth, involving various degrees of failed external ear canal development. A true external ear canal is desirable, as devices that replace the canal are inconvenient and expensive. Therefore, an optimal surgical technique is required. Here, we review useful preoperative and operative techniques. Surgical correction is often not the preferred treatment; the hearing outcome is no better than the outcomes afforded by bone-conduction devices, and surgery may be associated with recurrence or complications such as meatal stenosis. Preoperative evaluation and appropriate management are important. Several means of preventing meatal stenosis are discussed in this review.

Amplification options in unilateral aural atresia: an active middle ear implant or a bone conduction device?

BACKGROUND

There is no consensus on treatment of patients with congenital unilateral aural atresia. Currently, 3 intervention options are available, namely, surgical reconstruction, application of a bone-conduction device (BCD), or application of a middle ear implant.

OBJECTIVE

The present study aims to compare the BCD with the application of a middle ear implant. We hypothesized that cross-hearing (stimulating the cochlea by means of bone conduction contralateral to the implanted side) would cause BCD users to have difficulty performing localization tasks.

METHODS

Audiologic data of 4 adult patients with a middle ear implant coupled directly to the cochlea were compared with data of 4 adult patients fitted with an osseointegrated BCD. All patients were fitted during adulthood. The emphasis of this study is on directional hearing.

RESULTS

The middle ear implant and the BCD improved sound localization of patients with congenital unilateral aural atresia. Unaided scores demonstrate a large variation.

CONCLUSION

Our results demonstrate that there was no advantage of the middle ear implant over the BCD for directional hearing in patients who had no amplification in childhood. The BCD users had the best bandwidth.

Two-stage aural atresia and stenosis surgery with the use of synthetic skin substitute

CONCLUSION

With this technique, patency rates achieved in congenital external ear canal (EAC) atresia/stenosis and improvement in hearing were evaluated as 'good' and 'satisfactory', respectively.

OBJECTIVES

We aimed to test the efficacy of a novel two-stage technique in preventing restenosis following atresioplasty.

PATIENTS AND METHODS

Nine patients with congenital EAC atresia/stenosis comprised our cases. We performed 10 atresioplasties using the two-stage technique described below. In the first stage, the ear canal is drilled and its wall is covered with a synthetic skin replacement that induces proliferation of a soft tissue; in the second stage this is lined underneath with split thickness skin graft. Operations were complemented with tympanoplasties in five of the patients.

RESULTS

Nine (91%) of 10 operations carried out with the technique were largely successful in terms of patency. The achieved average hearing gain was air conduction/bone conduction (Ac/Bc): 31.33/9.44 dBHL (21.89 in the air-bone gap), while the postoperative air-bone conduction gap was changed to <30 dBHL in eight (88.9%) of the patients.

Oculo-auriculo-vertebral spectrum: associated anomalies, functional deficits and possible developmental risk factors

Swedish patients with the oculo-auriculo-vertebral (OAV) spectrum participated in a prospective multidisciplinary investigation. The aims of the study were to describe their systemic and functional defects, especially autism spectrum disorders, and to search for possible etiologic risk factors. Available medical records were studied and the mothers answered a questionnaire on history of prenatal events. A clinical examination evaluating systemic findings, vision, hearing, speech, oral and swallowing function, and neuropsychiatric function, especially autism, was made. Eighteen patients, (11 males, 7 females) aged 8 months to 17 years with OAV were studied. Most frequent systemic malformations included, ear abnormalities (100%), ocular malformations (72%), vertebral deformities (67%), cerebral anomalies (50%), and congenital heart defects (33%). Functional defects consisted of hearing impairment (83%), visual impairment (28%), both visual and hearing impairment (28%), difficulties in feeding/eating (50%), speech (53%), mental retardation (39%), and severe autistic symptoms (11%). Three children were born following assisted fertilization (two intracytoplasmatic sperm injection, one in vitro fertilization), two mothers reported early bleedings, and six (33%) mothers had smoked during pregnancy.

CHARGE association in Sweden: Malformations and functional deficits

CHARGE association (CA) consists of a non-random association of ocular coloboma (C), heart anomaly (H), atresia of choanae (A), retarded growth and/or development (R), genital hypoplasia (G), and ear anomalies and/or hearing impairment (E). A prospective multidisciplinary study of 31 Swedish patients with CA was undertaken in order to describe the associated malformations and functional deficits, find possible etiological factors and identify critical time periods for the maldevelopment. The clinical files were analyzed, the mothers answered a questionnaire on history of prenatal events, and a clinical evaluation of systemic findings, vision, hearing, balance, speech, oral and swallowing function, and neuro-psychiatric function, especially autism, was performed. The most frequent physical abnormalities affected ears (90%), eyes (90%), brain (61%), heart (52%), retarded growth (48%), genitals (38%), choanae (35%), and facial nerve (32%). Sixty-one percent of the patients were visually impaired or blind, and 74% had hearing loss or deafness. Problems in balance, speech, and eating were common. Forty percent of the patients had autism/atypical autism, and 82% had developmental delay. Three children were born following assisted fertilization and two mothers had diabetes. The mothers reported infections, bleedings, and drug use during pregnancy. Analysis of possible critical time periods suggested that most malformations were produced early in pregnancy, mainly during post conceptual weeks 4, 5, and 6. A multidisciplinary approach is essential in the assessment and management of CA.

Osseointegrated implants in children: experience from our first 100 patients

This study was undertaken on 100 children aged 16 years or under intended for installation of osseointegrated implants. Of these, 76 had implants installed for bone-anchored hearing aids or prostheses. The main indication for implant installation was a bilateral ear malformation. Surgery was generally performed as a two-stage procedure with a healing time of 3 to 4 months in between. Available bone thickness was on average 2.5 mm, and lack of bone necessitated bone augmentation in 12 patients. Thirty-nine percent of implants were installed in contact with the dura, sigmoid sinus, or an air cell. Implant failures were 5.8% of 170 inserted fixtures. Adverse skin reactions appeared in 9.1% of patients over a 21-year follow-up period. Revision surgery was undertaken in 22% of patients because of appositional growth of the temporal bone. Of the 24 children considered but not found suitable for osseointegration surgery, plastic surgery was considered a better option, or growth of the temporal bone was awaited. It is concluded that the rate of implant failure is lower in children; the frequency of skin reactions is the same as in adults, but revision surgery is more common in young patients because of new bone formation. Our clinical experience supported by the data presented in this article suggests that the concept could be used with good functional and aesthetic results in children.

Diagnosis and management strategies in congenital atresia of the external auditory canal. Study Group on Otological Malformations and Hearing Impairment

This consensus report represents a distillation of current opinion regarding diagnosis and management of congenital aural atresia. It also takes into account the philosophical differences which exist in Europe. Congenital aural atresia requires prompt diagnosis, genetic counselling and an early assessment of hearing. In bilateral atresia, early amplification with a bone conduction hearing aid is essential for proper speech development. Further rehabilitation in bilateral cases is managed with surgical reconstruction in selected patients or by implantation of a bone-anchored hearing aid. Atresia repair surgery is worthwhile if proper patient selection is made by use of stringent audiological and radiological criteria and state of the art surgery is performed. The divergent views concerning indications, ideal age for surgery and surgical approach to achieve better hearing are discussed. Review of the literature demonstrated that even in the hands of the best surgeons a mean hearing gain of only 20-25 dB is achieved in atresia Type II, with 30-35 dB in Type I. Therefore, surgical reconstruction should only be done in the more favourable cases where post-operative hearing of <25-30 dB is attainable. Less favoured patients should be helped with bone-anchored hearing aids, as this type of surgery does not interfere with the future use of new techniques.

Hemifacial microsomia and treatment options for auricular replacement: A review of the literature

STATEMENT OF PROBLEM

Although surgical reconstruction is the treatment of choice for auricular deformities that result from hemifacial microsomia, the implant-retained auricular prosthesis must be considered when surgical reconstruction is not possible. The competent and successful practitioner should be knowledgeable of the nature of this congenital disease.

PURPOSE

This article reviewed the first and second branchial syndrome, treatment approaches, and potential advances in surgical and prosthetic rehabilitation for patients with hemifacial microsomia.

CONCLUSION

Advantages and disadvantages of autogenous and alloplastic ear reconstructions are discussed. New research initiatives, such as tissue engineering and fabrication of auricular prosthesis by CAD/CAM, offer the potential for improved treatment for the future treatment of hemifacial microsomia.

Clinical appearance of spontaneous and induced first and second branchial arch syndromes

The clinical appearance was investigated of 29 patients with mandibulofacial dysostosis, 26 with hemifacial microsomia, and seven with thalidomide-induced malformations affecting derivatives of the first and second branchial arches. Malformations of the external ear, ear canal, middle ear, zygoma, maxilla, mandible, and lower eye lid were prominent features of the syndromes. Facial nerve and 6th cranial nerve paralysis as well as anophthalmia or microphthalmia were seen only in patients with hemifacial microsomia and in the thalidomide-induced syndrome. We compared the clinical results with those in an animal model in which an induced first and second branchial arch syndrome depends on disturbed migration of neural crest cell during early embryogenesis. The critical time for a similar process in humans would be between the 20th and 29th days of pregnancy.

The Bone-Anchored Hearing Aid (BAHA) in Children with Auricular Malformations

A retrospective study was undertaken to evaluate the outcome of the use of the bone-anchored hearing aid (BAHA) in children. All patients included in the study had bilateral auricular malformations. Previous alternatives had been conventional hearing aids or surgical middle ear reconstruction. Thirty-seven patients under 16 years of age were studied. The most common syndrome in the group was Treacher Collins. Sixteen of the patients had earlier middle ear reconstruction, the results of which did not produce social hearing. Of 40 inserted fixtures to anchor the BAHA, three were lost during the follow-up period because of failed osseointegration. Skin reactions were graded according to a clinical scoring system and were determined to be comparable in number and severity to those of an adult population. All patients in the study considered the BAHA to be superior to earlier bone-conduction devices.

It is concluded that the BAHA is an excellent alternative to bone-conduction devices in children with auricular malformations. Middle ear surgery can be postponed until adulthood or abandoned, especially in syndromic patients in whom it is known to be difficult and unpredictable.

Ear surgery in Treacher Collins syndrome

The autosomal dominant hereditary Treacher Collins syndrome manifests itself phenotypically in dysmorphogenesis of particularly the first, but also the second branchial arch system. Consequently, 50% of patients with Treacher Collins syndrome have a congenital, generally pure conductive hearing loss resulting from a major or minor ear anomaly. The outcome of surgery to improve patients' hearing varies and is sometimes even disappointing. Thorough analysis of 33 cases (39 operated ears) and the strict application of a classification for the anomaly to each ear enabled us to gain insight into the most suitable surgical policy and to form a prognosis for reconstructive ear surgery.

Aided free-field thresholds in children with conductive hearing loss fitted with air- or bone-conduction hearing aids

Although conductive hearing loss is often found in children, few reports have appeared on the fitting of hearing aids in these children. In the present study, aided thresholds were determined in 40 children and 30 adults with pure conductive hearing loss (bone-conduction thresholds of 20 dB HL or less) who were successfully fitted with hearing aids. The patient group was split into subgroups according to the type of hearing aid used (bone-conduction hearing aid, binaural or monaural air-conduction hearing aids). Within each subgroup, the aided thresholds proved to be comparable between the adults and children and were nonconsistently related to the degree of (air-conduction) hearing loss. In the patients with a bone-conduction hearing aid, the aided free-field thresholds at the most important frequencies for speech perception (1, 2 and 4 kHz) were found to be between 20 and 30 dB HL, while in the patients with an air-conduction hearing aid, irrespective of whether it was applied monaurally or binaurally, these thresholds were between 15 and 20 dB HL. It is suggested that these values should be considered as target thresholds when fitting hearing aids in children with conductive hearing loss.

The bone-anchored hearing aid and bone-anchored epithesis for congenital ear malformations

Surgery for correction of aural atresia was performed on 156 ears in 111 patients. A comparison was made between plastic surgery for auricular reconstruction and the bone-anchored epithesis. Another comparison was performed between hearing improvement after reconstructive surgery for meatal and middle ear atresia and the bone-anchored hearing aid. It was found that the bone-anchored epithesis is an excellent alternative to plastic reconstructive surgery of the auricle. The bone-anchored hearing aid could be considered as a strong alternative to surgery in patients with meatal and middle ear atresia--especially in patients with advanced malformations. Neither the bone-anchored epithesis nor the bone-anchored hearing aid excludes the patient from reconstructive surgery later in life.

External auditory canal stenosis and partial atresia without associated anomalies

Unilateral or bilateral ear canal stenosis or atresia occurring without microtia or associated anomalies may go undetected during early childhood. Summaries of ten cases illustrate difficulties in making early diagnoses. An unusual case of inherited isolated bilateral external canal atresia occurring in a mother and daughter is included. Potential pitfalls in diagnosis and management are discussed.

Meatal atresia and hearing loss. Autosomal dominant and autosomal recessive inheritance

Thirty-six ears of 33 patients with a type II unilateral or bilateral meatal atresia were accepted for reconstructive surgery. Five families of these patients had a history of congenital aural atresia. In one the father and his son had unilateral microtia. Four families counted 2 affected sibs each. The autosomal dominant and autosomal recessive patterns of inheritance are discussed.