Surgical treatment of congenital aural atresia - is it still justified?

Biomedical application of materials for external auditory canal: History, challenges, and clinical prospects

Biomaterials play an integral role in treatment of external auditory canal (EAC) diseases. Regarding the special anatomic structure and physiological characteristics of EAC, careful selection of applicable biomaterials was essential step towards effective management of EAC conditions. The bioactive materials can provide reasonable biocompatibility, reduce risk of host pro-inflammatory response and immune rejection, and promote the healing process. In therapeutic procedure, biomaterials were employed for covering or packing the wound, protection of the damaged tissue, and maintaining of normal structures and functions of the EAC. Therefore, understanding and application of biomaterials was key to obtaining great rehabilitation in therapy of EAC diseases. In clinical practice, biomaterials were recognized as an important part in the treatment of different EAC diseases. The choice of biomaterials was distinct according to the requirements of various diseases. As a result, awareness of property regarding different biomaterials was fundamental for appropriate selection of therapeutic substances in different EAC diseases. In this review, we firstly introduced the characteristics of EAC structures and physiology, and EAC pathologies were summarized secondarily. From the viewpoint of biomaterials, the different materials applied to individual diseases were outlined in categories. Besides, the underlying future of therapeutic EAC biomaterials was discussed.

Comparison of Outcomes of Surgery Versus Implantable Device for the Treatment of Hearing Loss Associated With Congenital Aural Atresia: A Systematic Review and Meta-Analysis

OBJECTIVE

To compare audiometric outcomes, complications, and revisions required for implantable bone-conduction devices (BCDs) versus atresia surgery for the treatment of hearing loss associated with congenital aural atresia.

DATABASES REVIEWED

PubMed, Scopus, CINAHL.

METHODS

Databases were searched for English articles from inception to July 1, 2022, for studies reporting audiometric outcomes or complications for either BCDs or atresia surgery for the treatment of congenital aural atresia. Main outcome measures included pure-tone audiometry, air-bone gap, speech reception threshold, associated complications, and rates of revision for each treatment option.

RESULTS

We identified 973 abstracts, of which 89 were selected for data extraction and analysis. A total of 2,611 patients were included, 1,901 in the atresia surgery group and 710 in the BCDs group. A meta-analysis of single means was conducted for age and audiometric outcomes, and a meta-analysis of proportions was conducted for complications and revisions. The average short-term improvement in pure-tone audiometry for the BCDs group was 34.4 ± 1.6 dB compared with 22.4 ± 1.5 dB for the atresia surgery group, representing a significant difference (12.0 dB; 95% confidence interval, 11.9-12.2; p < 0.0001). A smaller proportion of complications were reported in the devices group (16.9%) compared with the atresia surgery group (45.7%). In addition, a smaller proportion of cases in the devices group required some degree of revision (17.8%) compared with the atresia surgery group (23.0%).

CONCLUSIONS

This study demonstrates that implantable BCDs have significantly better audiometric outcomes as well as a lower rate of complications and revisions required compared with atresia surgery.

Comparison of hearing outcomes in patients with congenital aural atresia managed with canaloplasty and bone conduction hearing devices

BACKGROUND

Treatment options for congenital aural atresia (CAA) include canaloplasty and implantation of an osseointegrated bone conduction device (OBCD). Few studies have compared hearing outcomes in these two treatment methods.

OBJECTIVES

Hearing outcomes and revision surgery rates were compared in CAA patients managed by canaloplasty and surgically implanted OBCD.

METHODS

This study retrospectively analyzed 36 patients with CAA at a single institution. The same surgeon performed canaloplasty on 23 patients. Hearing outcomes before surgery as well as 3 and 6 months after surgery were compared to those of 13 patients with OBCD implantation.

RESULTS

Postoperative hearing outcomes were better in the OBCD group, but the difference was not statistically significant. At 6-month follow-up, the hearing thresholds in the canaloplasty and OBCD group were 38.6 ± 21.4 and 31.9 ± 6.4 dB, respectively. The success rates 6 months after surgery were 75.0% in the canaloplasty group and 100% in the OBCD group. Two out of 23 patients in the canaloplasty group and 7 out of 13 patients in the OBCD group underwent revision surgery.

CONCLUSION

In terms of hearing, the outcome was better with the OBCD compared to canaloplasty. Canaloplasty may be an alternative option in patients who refuse OBCD implantation.

Anatomy and Development of the Mammalian External Auditory Canal: Implications for Understanding Canal Disease and Deformity

The mammalian ear is made up of three parts (the outer, middle, and inner ear), which work together to transmit sound waves into neuronal signals perceived by our auditory cortex as sound. This review focuses on the often-neglected outer ear, specifically the external auditory meatus (EAM), or ear canal. Within our complex hearing pathway, the ear canal is responsible for funneling sound waves toward the tympanic membrane (ear drum) and into the middle ear, and as such is a physical link between the tympanic membrane and the outside world. Unique anatomical adaptations, such as its migrating epithelium and cerumen glands, equip the ear canal for its function as both a conduit and a cul-de-sac. Defects in development, or later blockages in the canal, lead to congenital or acquired conductive hearing loss. Recent studies have built on decades-old knowledge of ear canal development and suggest a novel multi-stage, complex and integrated system of development, helping to explain the mechanisms underlying congenital canal atresia and stenosis. Here we review our current understanding of ear canal development; how this biological lumen is made; what determines its location; and how its structure is maintained throughout life. Together this knowledge allows clinical questions to be approached from a developmental biology perspective.

Epithelial dynamics shed light on the mechanisms underlying ear canal defects

Defects in ear canal development can cause severe hearing loss as sound waves fail to reach the middle ear. Here, we reveal new mechanisms that control human canal development and highlight for the first time the complex system of canal closure and reopening. These processes can be perturbed in mutant mice and in explant culture, mimicking the defects associated with canal atresia. The more superficial part of the canal forms from an open primary canal that closes and then reopens. In contrast, the deeper part of the canal forms from an extending solid meatal plate that opens later. Closure and fusion of the primary canal was linked to loss of periderm, with failure in periderm formation in Grhl3 mutant mice associated with premature closure of the canal. Conversely, inhibition of cell death in the periderm resulted in an arrest of closure. Once closed, re-opening of the canal occurred in a wave, triggered by terminal differentiation of the epithelium. Understanding these complex processes involved in canal development sheds light on the underlying causes of canal atresia.

Highlighted Article: We reveal new mechanisms that control development of the ear canal and highlight for the first time the complex system of canal closure and reopening.

Long-term results of atresiaplasty in patients with congenital aural atresia

OBJECTIVES

To evaluate long-term benefits of atresiaplasty on hearing and the impact of surgery on quality of life (QoL) in congenital aural atresia (CAA) patients.

METHODS

We evaluated the long-term hearing results, the impact of atresiaplasty on QoL, the meatal diameter of the operated ear canal, and the cumulative number of post-operative hospital visits in 14 CAA patients, on average, 12 years (range: 4-17 years) post-operatively.

RESULTS

The mean preoperative pure tone average (PTA) was 61 dB HL. The postoperative short-term PTA was 36 dB HL and the long-term PTA was 51 dB HL. The mean total Glasgow Benefit Inventory (GBI) score was 16 (range: -11-39), showing the positive benefit of atresiaplasty on QoL. The mean postoperative diameter of the auditory meatus was 6 mm. The average number of hospital outpatient visits during the first postoperative year was 10.

CONCLUSION

Surgery for CAA is a demanding operation with variable anatomical and hearing outcomes. Atresiaplasty operations should be centralized to hospitals with large numbers of such patients to ensure sufficient levels of surgical experience. Bone-anchored hearing devices or middle-ear implants should be considered as a first-line option because they offer good hearing predictability.

[The interdisciplinary approach to the rehabilitation of the patients presenting with congenital atresia of the external auditory canal and the concomitant microtia]

The objective of the present study was to develop and introduce into the clinical practice the method for the combined aesthetic and functional rehabilitation of the patients presenting with congenital atresia of the external auditory canal (CAEAC) and the concomitant microtia. A total of 8 patients at the age from 6 to 21 years with unilateral CAEAC and microtia were given the surgical treatment. During the intervention, atresia was resolved using the trans-mastoid approach, tympanoplasty of autofasciae and ossiculoplasty making use of the partial titanium prosthesis and the placement of cranial osteointegratable titanium implants. At the second stage of the surgical intervention the 3D silicone prosthesis of the auricle shaped on an individual basis were used. The long-term follow-up observations have demonstrated the stable formation of the tube of the external auditory canal, with the bone-air interval amounting to 15-20 dB. The auricular prosthesis was the mirror image of the natural ear and completely concealed the congenital defect.

Middle ear abnormalities in Van Maldergem syndrome

Van Maldergem syndrome (VMS) is a very rare syndrome that was first described in 1992. The main features of this syndrome comprise intellectual disability, blepharo-naso-facial malformation, and hand anomalies. Almost all nine described patients have been shown to be affected by conductive hearing impairment attributed to microtia, and atresia of the outer ear canal. Here, we present a VMS patient with congenital malformations of the middle ear as the main reason for severe conductive bilateral hearing impairment. To our knowledge, this is the first report to describe middle ear abnormalities in VMS. These malformations were seen on high resolution Computed Tomography scanning and during an exploratory tympanotomy. Due to the severity of the middle ear abnormalities and the risk for facial nerve damage, the patient was not offered an ossicular chain reconstruction but a bone conduction device after this exploratory tympanotomy. © 2016 Wiley Periodicals, Inc.