[High resolution computerized tomography of middle ear abnormalities]

[Contemporary diagnosis and management of congenital microtia and aural atresia : Part 1: Principles and diagnosis]

Congenital malformations of the pinna and aural atresia can result in major aesthetic and functional deficits. Knowledge about embryologic developments and established classification systems is an essential requirement when dealing with affected patients. Early detection of deficiencies and introduction of appropriate diagnostic measures is vital to initiate adequate therapies and prevent long-term disabilities. Treatment for malformations of the pinna-if requested-is mostly surgical, infrequently an epithesis is applied. As in other surgical fields, tissue engineering will likely play a crucial role in the future. Treatment of aural stenosis and atresia aims at improvement of hearing levels and prevention of secondary complications like cholesteatoma and chronic otorrhea. Auditory rehabilitation comprises a spectrum from conventional hearing aids to invasive hearing implants, the latter being favored in recent years.

Pearls of Temporal Bone Imaging in Children with Hearing Loss

Hearing loss is one of the most common indications for temporal bone imaging in children. Hearing loss may be congenital or acquired, and it may be conductive, sensorineural, or mixed audiologically. Temporal bone imaging plays an important role in the assessment and management of this condition. An understanding of the embryology of ear structures better enables the radiologist to interpret abnormalities on imaging of the temporal bone. Here, we provide a general review of ear development and a description of known genetic defects that contribute to congenital ear anomalies associated with hearing loss. We provide appropriate imaging techniques for the temporal bone depending on the clinical presentation and a systematic approach to imaging for children with hearing loss. Diagnostic imaging for developmental anomalies of the ear and cholesteatoma will be discussed.

[Hearing rehabilitation with the Vibrant Soundbridge in patients with congenital middle ear malformation]

BACKGROUND

Congenital aural atresia, which is usually unilateral, causes hearing loss and aesthetic impairment. Besides tympanoplasty with/without canalplasty and bone conduction devices, active middle ear implants are also available for functional rehabilitation.

OBJECTIVE

This article aims to present a contemporary review on the treatment possibilities for middle ear malformations, with a focus on audiological rehabilitation with the Vibrant Soundbridge.

MATERIALS AND METHODS

A selective literature search for treatment possibilities was performed in PubMed up to October 2020, and personal clinical experiences are reported.

RESULTS

The Vibrant Soundbridge, which is approved for children ≥ 5 years, is suitable for treatment of middle ear malformations with a Jahrsdoerfer score ≥ 5. Although implantation of a Vibrant Soundbridge is surgically more demanding than implantation of a bone conduction device, the method is safe, delivers good auditory results (superior to bone conduction devices in terms of speech understanding and spatial hearing), does not involve intensive postsurgical care, and rarely requires revision surgery. The Vibrant Soundbridge can be coupled to (remnants of) the ossicular chain or the round window.

CONCLUSION

The Vibrant Soundbridge is an appropriate treatment method in patients with middle ear malformations who have suitable anatomical preconditions.

Ear malformations: what do radiologists need to know?

Ear malformations represent 50% of ear, nose and throat malformations. Ear malformations cause conductive hearing loss (CHL) and/or sensorineural hearing loss (SNHL) with a significant childhood disability worldwide. Early accurate diagnosis and treatment are mandatory to enhance language and speech development. Understanding the embryology of the ear explains the outcome of ototoxic prenatal insult according to the affected gestational age and the incidence of association among inner, middle, and external ear malformations. Computed tomography (CT) and magnetic resonance imaging (MRI) examinations of the temporal bone are used in the evaluation of ear malformations. In this review article, the spectrum of ear malformations is discussed in detail with hints on the ear embryology, the ear radiological anatomy, and radiological determinant factors of operative reconstruction of ear anomalies.

Conductive hearing loss with a "dry middle ear cleft"-A comprehensive pictorial review with CT

Conductive hearing loss (CHL) commonly results from middle ear fluid and inflammation (otitis media). Less commonly in patients with CHL, the middle ear cleft is well aerated or 'dry' with absence of soft tissue or fluid clinically and on imaging. There are numerous causes for this but they can be clinically challenging to diagnose. This pictorial review aims to illustrate and discuss the CT features of both common and less common causes of CHL in patients with a "dry middle ear cavity".

Minimal Reporting Standards for Active Middle Ear Hearing Implants

There is currently no standardized method for reporting audiological, surgical and subjective outcome measures in clinical trials with active middle ear implants (AMEIs). It is often difficult to compare studies due to data incompatibility and to perform meta-analyses across different centres is almost impossible. A committee of ENT and audiological experts from Germany, Austria and Switzerland decided to address this issue by developing new minimal standards for reporting the outcomes of AMEI clinical trials. The consensus presented here aims to provide a recommendation to enable better inter-study comparability.

Periosteal Flap Technique for Elevation of the Pinna in Microtia

IMPORTANCE

For optimal aesthetic construction of the auricle in patients with severe microtia, it is important to construct an exquisite framework and place it in the correct natural position. In addition to its accurate vertical and sagittal positioning, normal elevation is of utmost importance because this determines the auricular width from the common anterior view in interpersonal communication. Many techniques have been described to stabilize the constructed auricle in the elevated position. Some of the techniques are prone to relapse (eg, simple skin transplantation), while others are intricate (eg, using cartilage, huge pedicled flaps, and free skin grafts).

OBSERVATIONS

The objective of the study was to describe a simple and reliable periosteal flap technique and present our experience in 158 patients with complete unilateral or bilateral ear deformity (with possible defects of the external auditory meatus) who were operated on between February 3, 2005, and August 27, 2012. Principles of the technique include elevating the framework from the posterior aspect, stabilizing it with autogenous rib cartilage, covering this with a novel periosteal flap, and skin grafting.

CONCLUSIONS AND RELEVANCE

The periosteal flap technique proved to be straightforward and reliable. All flaps had unrestricted microcirculation. Good and stable projection of the auricle was achieved in all patients.

Malformation and plastic surgery in childhood

Malformations of the head and neck show a huge variety of clinical symptoms with functional and esthetic consequences. Often times its rehabilitation requires multi-staged and multi-disciplinary procedures and concepts. These must consider eating, speech, mimic expression, hearing and "esthetics" or at least "normality". A survey of the most common head and neck malformations and their treatment options are presented here.

[Malformations and abnormalities of the petrous portion of the temporal bone]

High-resolution computed tomography (HRCT) is the procedure of choice in the diagnostics of abnormalities of the middle and inner ear. It allows a detailed presentation of anatomical features and achieves the prerequisites for selection of the various therapeutic options. The highly diverse abnormalities can be described using detailed imaging analyses. Malformations with an abnormally developed modiolus are assumed to be early embryological defects, such as the classical Mondini dysplasia. The essential therapeutic option for middle ear deformities is still a cochlear implant. The domain of magnetic resonance imaging (MRI) is not only in the analysis of the cochlear nerve and for exclusion of fibrosis or ossification of the labyrinth but is also able to visualize details of isolated malformations, such as an extended vestibular aqueduct or subtle alterations to the vestibule or can visualize them better in comparison to CT. Radiological diagnostics are used not only for classification but also to recognize typical clinical problem situations and play a key role in the diagnostics of hearing disorders and selection of the optimal therapeutic procedure.

HRCT evaluation of microtia: A retrospective study

Purpose:

To determine external, middle, and inner ear abnormalities on high-resolution computed tomography (HRCT) of temporal bone in patients with microtia and to predict anatomic external and middle ear anomalies as well as the degree of functional hearing impairment based on clinical grades of microtia.

Materials and Methods:

It was a retrospective study conducted on Indian population. Fifty-two patients with microtia were evaluated for external, middle, and inner ear anomalies on HRCT of temporal bone. Clinical grading of microtia was done based on criteria proposed by Weerda et al. in 37 patients and degree of hearing loss was assessed using pure tone audiometry or brainstem-evoked response in 32 patients. Independent statistical correlations of clinical grades of micotia with both external and middle ear anomalies detected on HRCT and the degree of hearing loss were finally obtained.

Results:

The external, middle, and inner ear anomalies were present in 93.1%, 74.5%, and 2.7% patients, respectively. Combined cartilaginous and bony external auditory canal atresia (EAC) was the most common anatomic abnormality in our group of microtia patients. Hypoplastic mesotympanum represented the commonest middle ear anomaly. The incidence of combined ossicular dysplasia and facial canal anomalies was lower as compared to other population groups; however, we recorded a greater incidence of cholesteatoma. Both these factors can have a substantial impact on outcome of patients planned for surgery. We found no significant association between grades of microtia and external or middle ear anomalies. Similarly, no significant association was found between lower grades of microtia (grade I and II) and degree of hearing loss. However, association between grade III microtia and degree of hearing loss was significant. A significant association between congenital cholesteatoma and degree of pneumatization of atretic plate and mastoid process not previously studied was also recorded in our study.

Grading system for the selection of patients with congenital aural atresia for active middle ear implants

INTRODUCTION

Active middle ear implants (aMEI) are being increasingly used for hearing restoration in congenital aural atresia. The existing gradings used for CT findings do not meet the requirements for these implants. Some items are expendable, whereas other important imaging factors are missing. We aimed to create a new grading system that could describe the extent of the malformation and predict the viability and challenges of implanting an aMEI.

METHODS

One hundred three malformed ears were evaluated using HRCT of the temporal bone. The qualitative items middle ear and mastoid pneumatization, oval window, stapes, round window, tegmen mastoideum displacement and facial nerve displacement were included. An anterior- and posterior round window corridor, oval window and stapes corridor were quantified and novelly included. They describe the size of the surgical field and the sight towards the windows.

RESULTS

The ears were graded on a 16-point scale (16-13 easy, 12-9 moderate, 8-5 difficult, 4-0 high risk). The strength of agreement between the calculated score and the performed implantations was good. The comparison of the new 16-point scale with the Jahrsdoerfer score showed that both were able to conclusively detect the high-risk group; however, the new 16-point scale was able to further determine which malformed ears were favorable for aMEI, which the Jahrsdoerfer score could not do.

CONCLUSION

The Active Middle Ear Implant Score for aural atresia (aMEI score) allows more precise risk stratification and decision making regarding the implantation. The use of operative corridors seems to have significantly better prognostic accuracy than the Jahrsdoerfer score.

The role of HRCT and three-dimensional VR CT findings in patients of congenital atresia combined with microtia

OBJECTIVE

To determine the anatomic differences in patients of atresia by using high-resolution computed tomography (HRCT) and 3D volume rendered (VR) CT.

METHODS

High-resolution computed tomography (HRCT) was performed in 43 atresia patients including 34 unilateral atresia patients (n=34, 26 males, 8 females, mean age 13.82 years, range 8-19 years) and 9 bilateral atresia patients (6 males, 3 females, mean age 13.2 years, range 9-19 years). HRCT and 3D VR findings were compared with those in 43 normal ears of the unilateral atresia patients with normal PTA results (n=34, 26 males, 8 females, mean age 13.82 years, range 8-19 years) and 11 patients with sensorineural hearing loss but with no associated aplasia of the middle and inner ear (n=22, 7 males and 4 females, range 8-20.8 years, median age of 13.4 years) by using the independent one sample T test.

RESULTS

On the HRCT images, the angle between the basic line and the tympanic segment of the facial nerve is more acute. And the area of the malleus-incus-joint or the malleus-incus-complex in the diseased ears is smaller than that in the control subjects (P<0.05). The tympanic segment is shorter and the area of the tympanic cavity is smaller in the atresia group, while the diameter of the oval window is also smaller in atresia group than that in the control group (P<0.05). The morphologic differences of the small ossicles and the entire length of the tympanic and mastoid segments can be depicted on a single 3D VR CT image.

CONCLUSIONS

The facial nerve demonstrates abnormal lateral and anterior displacement in the CAA patients and the area of the Malleus-incus-joint and the tympanic cavity are significantly smaller, and the oval window is much narrower in the control group. HRCT and 3D VR CT provide valuable information about preoperative planning of patients with CAA. Measurements of all the angles and length serve as useful adjunct measurements in determining surgical candidacy.

Combined reconstruction of congenital auricular atresia and severe microtia

OBJECTIVES

Due to their embryologic developments, auricular atresia and severe microtia are in most cases combined malformations. The aims of this study were to develop a surgical technique for combined esthetic and functional reconstruction with a minimum of operations and to evaluate the results.

STUDY DESIGN

Prospective clinical evaluation.

PATIENTS AND METHODS

Fifty-two patients with third-degree microtia and congenital aural atresia with a sound-conducting block of about 50 dB were treated as described here. In the first operation, autogenous cartilage is harvested and the auricular framework fabricated and implanted. In addition, the tympanic membrane and the external ear canal are prefabricated and stored in a subcutaneous pocket. In the second step, the elevation of the new framework is combined with the operation for atresia utilizing the prefabricated tympanic membrane and external ear canal. In the third step, the cavum conchae is deepened and the external ear canal opened and covered with a skin graft.

RESULTS

Seventy-six percent of the patients had a final conducting hearing loss of 30 dB or less. No restenosis of the new external ear canal was observed. The esthetic results of the constructed auricles are shown.

CONCLUSION

With this combination of plastic surgery for the auricle and functional surgery for the middle ear, no additional operations are necessary, and the prefabrication of the external ear canal and the tympanic membrane gives stable and reliable results. Therefore, we think that this combined technique offers the best chance for an optimal esthetic and functional rehabilitation of patients with these malformations.

Non-syndromal round window atresia: an autosomal dominant genetic disorder with variable penetrance?

Round window atresia can be seen in association with syndromal anomalies such as mandibulofacial dysostosis, Mondini type anomalies or cretinism, or with extensive otosclerosis. Non-syndromal round window atresia is extremely rare and until today there is no proof whether non-syndromal round window atresia can be inherited. We present two family members with non-syndromal round window atresia. Based on this case and on an extensive literature review, we discuss the possible ways of sound transmission with round window occlusion as well as the possibility of an autosomal dominant inheritance pattern of these two non-syndromal cases. Evaluating the hearing test results, the effect of round window atresia in non-syndromal cases cannot be thoroughly explained by current theories of sound transmission. In general, full occlusion of the round window should result in a complete air-bone-gap and a surgical procedure to open the window, e.g. a cochlear fenestration which creates a new pressure outlet for the inner ear fluids, should result in normalizing the hearing levels. Astonishingly, patients with non-syndromal round window atresia, show hearing tests similar to those in patients with otosclerosis. In contrast to otosclerosis, complete closure of the air-bone-gap by surgery in patients with round window atresia does not seem to be possible according to currently reported cases. Therefore, routine examination of the round window in stapes surgery should be part of every stapes surgery and a high resolution CT scan should be considered in particular prior to revision of unsuccessful stapes surgery. As a genetic inheritance pattern can be assumed, specific emphasis should also be laid on the patient's family history.

Fully Implantable Hearing Aids in Patients With Congenital Auricular Atresia

INTRODUCTION

Patients with congenital auricular atresia suffer from a conductive hearing loss (HL) with an air-bone gap of 50 to 60 dB. Conventional bone conducting or bone anchored hearing aids are treatment options with several disadvantages and a biophysical limitation of almost no sound attenuation in the skull bone. Surgical construction of the sound conducting apparatus has been performed by others and modified by us into a three-step procedure with in vivo prefabrication of the external ear canal and the tympanic membrane. Although the results improved after inauguration of our modifications, there still remains an air-bone gap that makes air conducting hearing aids necessary in many patients. Implantable hearing aids have been developed for patients with perceptional HL and normal middle ear function but not for patients with middle ear disease or malformation.

OBJECTIVES

Our objectives were to improve the hearing results of auricular atresia.

STUDY DESIGN

Prospective.

METHODS

The surgical instruments, the transducer, and the operative technique of the only fully implantable hearing aid (Otologics Fully Implantable Middle Ear Transducer) clinically available were modified. They were implanted in five patients with congenital auricular atresia and their audiologic outcome evaluated.

RESULTS

After activation and fitting of the devices, patients experienced an improvement of sound-field thresholds up to 50 dB HL. The mean functional gain in a three frequency pure-tone average was approximately 35 dB HL.

CONCLUSIONS

This technique appears to provide a completely new dimension for the audiologic rehabilitation of patients with severe malformation of the middle ear.

Navigation-Assisted Construction of an External Ear Canal Using an Autogenous Foreskin Graft

Classic microtia is combined with external ear canal atresia and middle ear malformation. In order to evaluate whether an operation to improve hearing ability and the use of computer-assisted surgery are indicated, preoperative high-resolution navigation CT is mandatory. We combined atresia surgery and tympanoplasty with auricular reconstruction in the case of an 8-year-old boy with bilateral microtia, aural atresia and malformation of the middle ear. After creating an auricle framework with rib cartilage and transplanting it under the skin of the mastoid plane, we shifted it forward in the second step, and the new auditory canal was drilled under computer-assisted navigation and facial nerve monitoring. In the same operation, tympanoplasty was accomplished, and a silastic cylinder, wrapped into pieces of rib cartilage, was inserted into the constructed canal and removed 2 months later. For lining the new auditory canal, we used the patient's prepuce, harvested by elective circumcision.

Two-Step External Ear Canal Construction in Atresia as Part of Auricular Reconstruction

OBJECTIVES

One of the common complications of atresia surgery is restenosis of the surgically constructed external ear canal. To avoid this complication, a new two-step technique of creating an external ear canal was developed and evaluated.

STUDY DESIGN

Prospective clinical evaluation.

PATIENTS AND METHODS

Thirty-six patients with third-degree microtia and aural atresia have been treated this way. In the first step, the canal is drilled into the petrous bone, a Silastic cylinder is inserted and wrapped into pieces of cartilage and bone dust. In the second step several months later, the implant is removed and a slightly smaller tube covered with a split thickness skin graft is inserted.

RESULTS

Except the first three patients operated with a slightly different technique, none of the following 33 patients showed a severe restenosis. Instead, all had a nice, smooth external ear canal.

CONCLUSION

With this two-step technique of creating a new external ear canal in atresia, we could avoid one of the major complications of this kind of surgery. The external ear canal is either necessary for the reconstructed middle ear or it can be used to adapt a (behind or in the ear) hearing aid. By integrating this technique into a three-step concept for auricular reconstruction, the patient does not need any additional operation, and his or her rehabilitation from ear malformation can be enhanced.