Masses and disease entities of the external auditory canal: Radiological and clinical correlation

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.

Acquired Stenosis of the External Ear Canal

Acquired stenosis of the external ear canal (ASEEC) is a relatively uncommon condition. Stenosis or narrowing of the external ear canal (EEC) occurs lateral to the tympanic membrane resulting in a skin lined blind canal. Recurrent otorrhea, and conductive hearing loss are typical clinical features. Although ASEEC can be due to different etiologies, a common pathogenesis, namely an inflammatory cascade, has been implicated. Clinical evaluation, audiogram, and Computed tomography (CT scan) form the mainstay of diagnosis. Surgery is the primary modality for treatment. Restenosis is the most common postsurgical complication.

Imaging the External Ear: Practical Approach to Normal and Pathologic Conditions

The external ear (EE) is an osseous-cartilaginous structure that extends from the auricle to the tympanic membrane. It is divided into two parts: the auricle (or pinna) and the external auditory canal (EAC). Given the ease of access to the EE, imaging studies are not always needed to make a diagnosis. However, when lesions block visual access to areas deep to the EE abnormality, complications are suspected, or there is lack of response to treatment, imaging becomes essential. A basic understanding of the embryologic development and knowledge of the anatomy of the auricle and EAC are useful for accurate diagnosis of EE lesions. Congenital, traumatic, inflammatory, neoplastic, and vascular conditions can affect the EE. An overview of the anatomy and embryologic development of the EE is presented, with discussion and illustrations of common and uncommon conditions that affect EE structures and a focus on the CT and MRI features that are of interest to radiologists. CT is usually the first diagnostic modality used to evaluate the EAC and is the superior method for demonstrating bone changes. MRI provides excellent tissue characterization and enables one to better define lesion extension and perineural tumor spread. In addition, a flowchart to facilitate the differential diagnosis of EE abnormalities is provided. Online supplemental material is available for this article. ^©RSNA, 2022.

External auditory exostoses and early Neolithic aquatic resource procurement in Cyprus: Results from Cypro-PPNB Kissonerga-Mylouthkia in regional context

OBJECTIVE

This research is designed to evaluate the occurrence of external auditory exostoses (EAEs) in skeletal remains from the oldest known water wells in the world (Kissonerga-Mylouthkia, Cyprus, 8,200-7,200 BCE).

MATERIALS

Six individuals (MNI = 6), five fragmentary temporalia, two preserved auditory canals.

METHODS

Macroscopic and microscopic (up to x30) observation, with illumination; presence, type, side, severity, occlusion, number, and position of bony growths recorded.

RESULTS

Bony growths within two auditory canals were discovered. Differential diagnosis includes osteomata and external auditory exostoses, with the latter consistent with the bony growths (Grade 1 EAEs, two adult males, one with single, another with two EAEs).

CONCLUSIONS

The emergence of the Neolithic in Southwest Asia is thought to involve increases in dietary breadth among foraging societies (Broad-Spectrum Revolution). EAEs likely indicate maritime activity in this context, given the lack of freshwater bodies, and zooarchaeological evidence points to dietary and other uses of maritime organisms.

SIGNIFICANCE

This EAE evidence is the oldest known in maritime contexts in Eastern Mediterranean and the Middle East, and first in Cyprus. It contributes towards understanding the initial colonization events by Neolithic farming communities in the 9th millennium BC, and the emergence of broad-spectrum economies at the dawn of the Neolithic in Southwest Asia, crucial for re-considerations of paradigms on the transition to the Neolithic way of life in the Near East.

LIMITATIONS

Only a few skeletal remains from these prehistoric contexts were available for observation.

SUGGESTIONS FOR FURTHER RESEARCH

Further intensive review of Cypriot skeletal collections for EAEs is advised.

External auditory exostoses among western Eurasian late Middle and Late Pleistocene humans

External auditory exostoses (EAE) have been noted among the Neandertals and a few other Pleistocene humans, but until recently they have been discussed primary as minor pathological lesions with possible auditory consequences. An assessment of available western Eurasian late Middle and Late Pleistocene human temporal bones with sufficiently preserved auditory canals (n = 77) provides modest levels of EAE among late Middle Pleistocene archaic humans (≈20%) and early modern humans (Middle Paleolithic: ≈25%; Early/Mid Upper Paleolithic: 20.8%; Late Upper Paleolithic: 9.5%). The Neandertals, however, exhibit an exceptionally high level of EAE (56.5%; 47.8% if two anomalous cases are considered normal). The levels of EAE for the early modern humans are well within recent human ranges of variation, frequencies which are low for equatorial inland and high latitude samples but occasionally higher elsewhere. The Early/Mid Upper Paleolithic frequency is nonetheless high for a high latitude sample under interpleniglacial conditions. Given the strong etiological and environmental associations of EAE development with exposure to cold water and/or damp wind chill, the high frequency of EAE among the Neandertals implies frequent aquatic resource exploitation, more frequent than the archeological and stable isotopic evidence for Middle Paleolithic/Neandertal littoral and freshwater resource foraging implies. As such, the Neandertal data parallel a similar pattern evident in eastern Eurasian archaic humans. Yet, factors in addition to cold water/wind exposure may well have contributed to their high EAE frequencies.

Post-inflammatory acquired atresia of the external auditory canal

Acquired atresia of the external auditory canal (EAC) is a rare cause of conductive hearing loss. It has been traditionally classified into 4 categories: traumatic, post-operative, neoplastic and inflammatory. Post-inflammatory acquired auditory canal atresia is thought to be the result of chronic and repetitive infectious bouts affecting the auditory canal. Nevertheless, the underlying pathophysiology of this disorder is yet to be fully elucidated. Current data fail to clearly state the impact that certain underlying systemic disorders may have on the EAC. The possible association to metabolic disturbances such as iron deficiency is also emphasized. In the light of these findings, this analysis can be used to improve the classification of this entity thereby standardizing the assessment of therapeutic approaches.

External auditory exostoses in the Xuchang and Xujiayao human remains: Patterns and implications among eastern Eurasian Middle and Late Pleistocene crania

In the context of Middle and Late Pleistocene eastern Eurasian human crania, the external auditory exostoses (EAE) of the late archaic Xuchang 1 and 2 and the Xujiayao 15 early Late Pleistocene human temporal bones are described. Xujiayao 15 has small EAE (Grade 1), Xuchang 1 presents bilateral medium EAE (Grade 2), and Xuchang 2 exhibits bilaterally large EAE (Grade 3), especially on the right side. These cranial remains join the other eastern Eurasian later Pleistocene humans in providing frequencies of 61% (N = 18) and 58% (N = 12) respectively for archaic and early modern human samples. These values are near the upper limits of recent human frequencies, and they imply frequent aquatic exposure among these Pleistocene humans. In addition, the medial extents of the Xuchang 1 and 2 EAE would have impinged on their tympanic membranes, and the large EAE of Xuchang 2 would have resulted in cerumen impaction. Both effects would have produced conductive hearing loss, a serious impairment in a Pleistocene foraging context.

External auditory exostoses and hearing loss in the Shanidar 1 Neandertal

The Late Pleistocene Shanidar 1 older adult male Neandertal is known for the crushing fracture of his left orbit with a probable reduction in vision, the loss of his right forearm and hand, and evidence of an abnormal gait, as well as probable diffuse idiopathic skeletal hyperostosis. He also exhibits advanced external auditory exostoses in his left auditory meatus and larger ones with complete bridging across the porus in the right meatus (both Grade 3). These growths indicate at least unilateral conductive hearing (CHL) loss, a serious sensory deprivation for a Pleistocene hunter-gatherer. This condition joins the meatal atresia of the Middle Pleistocene Atapuerca-SH Cr.4 in providing evidence of survival with conductive hearing loss (and hence serious sensory deprivation) among these Pleistocene humans. The presence of CHL in these fossils thereby reinforces the paleobiological and archeological evidence for supporting social matrices among these Pleistocene foraging peoples.

Air and Bone Conduction Frequency-specific Auditory Brainstem Response in Children with Agenesis of the External Auditory Canal

Introduction  The tone-evoked auditory brainstem responses (tone-ABR) enable the differential diagnosis in the evaluation of children until 12 months of age, including those with external and/or middle ear malformations. The use of auditory stimuli with frequency specificity by air and bone conduction allows characterization of hearing profile.

Objective  The objective of our study was to compare the results obtained in tone-ABR by air and bone conduction in children until 12 months, with agenesis of the external auditory canal.

Method  The study was cross-sectional, observational, individual, and contemporary. We conducted the research with tone-ABR by air and bone conduction in the frequencies of 500 Hz and 2000 Hz in 32 children, 23 boys, from one to 12 months old, with agenesis of the external auditory canal.

Results  The tone-ABR thresholds were significantly elevated for air conduction in the frequencies of 500 Hz and 2000 Hz, while the thresholds of bone conduction had normal values in both ears. We found no statistically significant difference between genders and ears for most of the comparisons.

Conclusion  The thresholds obtained by bone conduction did not alter the thresholds in children with conductive hearing loss. However, the conductive hearing loss alter all thresholds by air conduction. The tone-ABR by bone conduction is an important tool for assessing cochlear integrity in children with agenesis of the external auditory canal under 12 months.

External auditory canal meningioma: imaging features in a series of three cases

BACKGROUND

Direct extension of an intracranial meningioma to involve the temporal bone is rare. Recognised sites of origin and routes of access to the middle ear and labyrinthine apparatus have been described. Direct spread through the temporal bone to primarily involve the external auditory canal has not been widely reported in the literature.

CASE REPORTS

This paper discusses clinical and radiological findings in three cases of temporal bone meningioma presenting as masses within the external auditory canal.

CONCLUSION

Diagnosing temporal meningioma can be challenging because of its rarity and the often non-specific clinical and histological findings. It is important for both the surgeon and radiologist to be aware of the diagnosis and its related imaging findings in order to facilitate a timely diagnosis.

Investigation of demodex species frequency in patients with a persistent itchy ear canal treated with a local steroid

OBJECTIVE

To investigate the frequency of demodex species in the external acoustic meatus in patients with an itchy ear canal.

METHODS

Patients were assigned to one of three groups. Group one consisted of 54 patients with an itchy ear canal who were using a local agent, while group two was composed of 51 patients with an itchy ear canal who were not using a local agent. Group three consisted of 50 healthy individuals without an itchy ear canal.

RESULTS

Demodex species test results were positive in nine (5.8 per cent) of the cases. Six of these positive cases were in group one, two in group two and one in group three. The frequency of demodex species in the external acoustic meatus was similar between those patients with an itchy ear canal who did not use a local agent and the healthy individuals (p = 0.571), but it was significantly higher in those using a local steroid compared with those not using a local agent (p = 0.046).

CONCLUSION

Although demodex species was not significantly higher in patients with an itchy ear canal compared with the control group, use of a local steroid increased the parasite frequency in the external ear canal of affected patients.