Auditory Canal Research Articles

Imaging of the vascular distribution of the outer ear using optical coherence tomography angiography for highly accurate positioning of a hearable sensor.

Novel hearable technology is securely and comfortably positioned within the ear canal minimizing inaccuracies caused by accessory movements during activities. Despite extensive research on hearable technologies within the outer ear, there is a lack of research in the field of vascular imaging and quantitative analysis in the outer ear in vivo, which is one of the crucial factors to select the appropriate sensor position. Therefore, in this paper, we introduced optical coherence tomography angiography (OCTA)-based qualitative and quantitative analyses to visualize the inner vasculature of the outer ear to acquire vascular maps for microvascular assessments in vivo. By generating maximum amplitude projection images from three-dimensional blood vascular volume, we identified variations of blood vessel signal caused by the different biological characteristics and curvature of the ear among individuals. The performance of micro-vascular mapping using the proposed method was validated through the comparison and analysis of individual vascular parameters using extracted 20 vascular-related variables. In addition, we extracted pulsatile blood flow signals, demonstrating its potential to provide photoplethysmographic signals and ear blood maps simultaneously. Therefore, our proposed OCTA-based method for ear vascular mapping successfully provides quantitative information about ear vasculature, which is potentially used for determining the position of system-on-chip sensors for health monitoring in hearable devices.

Microbiome of the External Auditory Canal: Changes After Long-Term Hearing Aid Use.

To investigate the microbial changes of long-term hearing aid use culture independently. Cross-sectional study. Fifty long-term hearing aid users and 80 volunteer controls with asymptomatic ears. External auditory canal (EAC) sampling with DNA-free swabs. Microbial communities in the samples were investigated with amplicon sequencing of the 16S rRNA gene. The final analysis contained 48 hearing aid users, 59 controls. Twenty-four samples were excluded because of low sequence count, recent use of antimicrobials and/or corticosteroids, recent cold, or missing health status. The groups showed significant differences in bacterial diversity (beta div., p = 0.011), and hearing aid users showed lower species richness than the control group (alpha div., p < 0.01). The most frequent findings in both groups were Staphylococcus auricularis , Alloiococcus otitis , Cutibacterium acnes , Corynebacterium otitidis , and Staphylococcus unclassified sp. Hearing aid users' samples presented more Corynebacterium tuberculostearicum than the control samples. Common EAC pathogens, such as Staphylococcus aureus or Pseudomonas aeruginosa were rare. Long-term hearing aid use lowers bacterial diversity and modulates the EAC microbiome. The changes mostly affect commensals. Lowered diversity may predispose individuals to EAC conditions and needs more research.

Wide Cortical Drilling and Anterior-Based Periosteal Flap Reconstruction: Innovative Approach for Acquired Stenosis of External Auditory Canal

In patients with acquired stenosis of external auditory canal, traditional canaloplasty surgery using skin graft may be performed when symptoms are severe or persistent. However, the risk of restenosis during follow-up period remains a main concern for surgeons. Herein, we present a novel surgical technique using wide cortical bone drilling and reconstruction using the anterior-based periosteal flap. We also report the preliminary results of case series using this surgical technique comparing it with the traditional method.

Intracranial pressure following surgery of an unruptured intracranial aneurysm—a model for normal intracranial pressure in humans

ObjectiveOptimizing the treatment of several neurosurgical and neurological disorders relies on knowledge of the intracranial pressure (ICP). However, exploration of normal ICP and intracranial pressure pulse wave amplitude (PWA) values in healthy individuals poses ethical challenges, and thus the current documentation remains scarce. This study explores ICP and PWA values for healthy adults without intracranial pathology expected to influence ICP.MethodsAdult patients (age > 18 years) undergoing surgery for an unruptured intracranial aneurysm without any other neurological co-morbidities were included. Patients had a telemetric ICP sensor inserted, and ICP was measured in four different positions: supine, lateral recumbent, standing upright, and 45-degree sitting, at day 1, 14, 30, and 90 following the surgery.ResultsICP in each position did not change with time after surgery. Median ICP was 6.7 mmHg and median PWA 2.1 mmHg in the supine position, while in the upright standing position median ICP was − 3.4 mmHg and median PWA was 1.9 mmHg. After standardization of the measurements from the transducer site to the external acoustic meatus, the median ICPmidbrain was 8.3 mmHg in the supine position and 1.2 mmHg in the upright standing position.ConclusionOur study provides insights into normal ICP dynamics in healthy adults following a uncomplicated surgery for an unruptured aneurysm. These results suggest a slightly wider normal reference range for invasive intracranial pressure than previously suggested, and present the first normal values for PWA in different positions. Further studies are, however, essential to enhance our understanding of normal ICP.Trial registration The study was preregistered at www.clinicaltrials.gov (NCT03594136) (11 July 2018)

2 Cases of Intra-Labyrinthine Schwannomas With Different Treatment Options Based on Clinical Presentation

Vestibular schwannoma is a benign tumor that arises from the eighth cranial nerve and is the most common neoplasm in the internal auditory canal (IAC). It typically arises in the cerebellopontine angle or in IAC; however, in rare cases, they can arise within the labyrinth. These tumors arising in the labyrinth have been termed intra-labyrinthine schwannomas (ILS) and have different clinical features than the typical vestibular schwannomas. Clinical manifestations of an ILS typically include hearing loss, tinnitus, and vertigo, with unusual symptoms including a sense of fullness or imbalance. Temporal bone MRI is considered the most important test for diagnosing ILS. Tumors show nodular enhancement on T1-weighted images and filling defects on T2-weighted images. Treatment of ILS may include observation, microsurgical resection, and stereotactic radiosurgery depending on the location, size, and clinical presentation. In this paper, we present two cases diagnosed as ILS with different treatment options and provide a literature review for each case.

Effects of Tympanic Membrane Electrodes on Sound Transmission From the Ear Canal to the Middle and Inner Ears.

The first objective of the study was to compare approaches to eardrum electrode insertion as they relate to the likelihood of introducing an acoustic leak between the ear canal and eartip. A common method for placing a tympanic membrane electrode involves securing the electrode in the canal by routing it underneath a foam eartip. This method is hypothesized to result in a slit leak between the canal and foam tip due to the added bulk of the electrode wire. An alternative approach involves creating a bore in the wall of the foam tip that the electrode can be threaded through. This method is hypothesized to reduce the likelihood of a slit leak before the electrode wire is integrated into the foam tip. The second objective of the study was to investigate how sound transmission in the ear is affected by placing an electrode on the eardrum. It was hypothesized that an electrode in contact with the eardrum increases the eardrum's mass, with the potential to reduce sound transmission at high frequencies. Wideband acoustic immittance and distortion product otoacoustic emissions (DPOAEs) were measured in eight human ears. Measurements were completed for five different conditions: (1) baseline with no electrode in the canal, (2) dry electrode in the canal but not touching the eardrum, secured underneath the eartip, (3) dry electrode in the canal not touching the eardrum, secured through a bore in the eartip (subsequent conditions were completed using this method), (4) hydrated electrode in the canal but not touching the eardrum, and (5) hydrated electrode touching the eardrum. To create the bore, a technique was developed in which a needle is heated and pushed through the foam eartip. The electrode is then thread through the bore and advanced slowly by hand until contacting the eardrum. Analysis included comparing absorbance, admittance phase angle, and DPOAE levels between measurement conditions. Comparison of the absorbance and admittance phase angle measurements between the electrode placement methods revealed significantly higher absorbance and lower admittance phase angle from 0.125 to 1 kHz when the electrode is routed under the eartip. Absorbance and admittance phase angle were minimally affected when the electrode was inserted through a bore in the eartip. DPOAE levels across the different conditions showed changes approximating test-retest variability. Upon contacting the eardrum, the absorbance tended to decrease below 1 kHz and increase above 1 kHz. However, changes were within the range of test-retest variability. There was evidence of reduced levels below 1 kHz and increased levels above 1 kHz upon the electrode contacting the eardrum. However, differences between conditions approximated test-retest variability. Routing the eardrum electrode through the foam tip reduces the likelihood of incurring an acoustic leak between the canal walls and eartip, compared with routing the electrode under the eartip. Changes in absorbance and DPOAE levels resulting from electrode contact with the eardrum implicate potential stiffening of eardrum; however, the magnitude of changes suggests minimal effect of the electrode on sound transmission in the ear.

Demographic, Functional, and Risk Factors Characterization in Ecuadorian Mestizo Patients With Microtia: A Retrospective Study.

This paper compares demographic, morphological, functional, and risk factors between isolated and familial forms of microtia in Ecuadorian mestizo patients. The authors did an epidemiological, and retrospective study with 112 patients divided into isolated microtia (n = 91) and familial microtia (n = 21). Patients with syndromic microtia were not included. In isolated microtia, the mean age was 11.80 ± 16.9, and the most prevalent age group was from 5 to 9 years, with 45.0%; males were 58.2%, and 91.2% of patients were born in a city above 2500 meters about sea level. In familial microtia, the mean age was 15.57 ± 17.2. There were no statistically significant differences between the analyzed variables. In isolated microtia, 41.8% of patients had bilateral involvement, 40.7% had grade 1 microtia in the right ear (RE), and grade 1 in the left ear was 47.3%; external auditory canal atresia of RE was present in 62.6%, and in left ear in 31.6%. External auditory canal atresia sidedness was mostly unilateral in both groups. Most patients did not have tags or pits (78% and 81% in RE and 85.7% and 71.4%). Most patients had moderate hearing loss in both ears. The authors found an association between both microtia forms with external auditory canal atresia in RE; only 20% of patients had unilateral auricular tags or pits in both groups. The authors also found a high incidence (18.75%) of familial microtia, which suggests a distinct pathological genetic component than the more prevalent isolated cases. The authors found a high association of microtia cases from the Ecuadorian highlands above 2500 meters about sea level (over 90%). The presence of "social" intake of alcohol during pregnancy showed over twice the chance of having a child born with microtia.

Hyperbaric oxygen therapy in malignant otitis externa: a retrospective analysis.

Malignant otitis externa (MOE) is a rare form of invasive osteomyelitis of the external ear canal. It is typically caused by Pseudomonas aeruginosa in immunocompromised patients. The diagnosis is clinical, and the initial treatment involves systemic antibiotics or antifungal therapy. Surgery is usually only considered when medical treatment has failed. Although hyperbaric oxygen therapy (HBOT) is recommended for refractory osteomyelitis, there are no specific guidelines for MOE. This is a retrospective study that evaluates clinical data, treatment, and results obtained in patients diagnosed with MOE treated with HBOT at the Pedro Hispano Hospital between 2007 and 2022. During the study period, fifteen patients diagnosed with MOE were admitted for treatment with HBOT. All patients received antibiotic and/or antifungal therapy, and three required surgical intervention before starting HBOT. The pathology was successfully managed on all patients. HBOT may be an effective adjuvant treatment option in patients with MOE but it lacks robust scientific evidence. However, its therapeutic value should not be underestimated due to the good results and few adverse effects reported in recent retrospective studies and case reports.

Evaluation of Cochlear Implantation in Children With Cochlear Nerve Absence or Deficiency.

To identify associations between cochleovestibular anatomy findings and hearing outcomes found in children with imaging evidence of an absent or hypoplastic cochlear nerve treated with cochlear implantation (CI). retrospective review. Cochlear implant program at tertiary care center. A retrospective review was performed to identify children with imaging evidence of cochlear nerve absence or deficiency who underwent CI evaluation. High-resolution 3-dimensional T2-weighted magnetic resonance imaging in the oblique sagittal and axial planes were reviewed by a neuroradiologist to identify cochleovestibular anatomy. Hearing was assessed pre and postoperatively with Speech Perception Category scores. Seven CI recipients were identified (n = 10 ears) who had bilateral severe to profound sensorineural hearing loss with lack of auditory development with binaural hearing aid trial and imaging evidence of cochlear nerve aplasia/hypoplasia. All ears had 2 nerves in the cerebellopontine angle (100%, n = 10), half of the ears had evidence of 2 or less nerves in the internal auditory canal (IAC). All children showed large improvement in speech perception after CI. Our experience with CIs for children with absent or hypoplastic cochlear nerves demonstrates that CI can be a viable option in select patients who satisfy preoperative audiological criteria. Radiological identification of a hypoplastic or aplastic cochlear nerve does not preclude auditory innervation of the cochlea. CI recipients in this subgroup must be counseled on difficulty in predicting postimplantation language and speech outcomes, and cautioned about facial nerve stimulation.

Transcriptome and proteome revealed the differences in 3 colors of earlobe in Jiangshan Black-bone chicken

The earlobe is a featherless, exposed thickening located beneath the ear canal of chickens, which plays a visual signaling role in age, performance, mental vitality, reproduction, and other aspects. However, despite its importance, there have been few studies on the color differences and formation mechanisms of chicken earlobes, particularly the structurally blue earlobes characteristic of the Jiangshan black-bone chicken. In this study, we explored the physiological mechanisms that may influence the formation of differently colored earlobes using 3 types of earlobes from Jiangshan black-bone chickens: light peacock green (Green group), dark peacock green (Blue group), and dark reddish purple (Black group). All 3 earlobe colors exhibited positive melanin Masson-Fontana staining, and the thickness of collagen fibers in the dermis decreased in the order of Green, Blue, and Black groups. A total of 1,953 differentially expressed genes (DEGs) were detected in the 3 earlobes through mRNA sequencing, among which the GO term "collagen trimer" was significantly enriched in DEGs between groups. Additionally, 716 differentially expressed proteins (DEPs) were identified in the 3 earlobes using 4D-DIA proteomics, with the term "collagen fibril organization" being significantly enriched in DEPs between the Green and Black groups. Integrated analysis of transcriptome and proteome data revealed that 12 DEGs and DEPs were commonly differentially expressed between the Green and Black groups, including the gene LUM (corneal keratan sulfate proteoglycan), which was significantly enriched in the "collagen fibril organization" GO term. In conclusion, our study suggests that LUM plays a crucial role in the formation of peacock green earlobes in Jiangshan black-bone chickens. The high level of LUM in peacock green (Green and Blue groups) may affect collagen nanostructures, leading to a stronger effect of melanin-supported dermal collagen on the production of non-iridescent structural colors through coherent scattering, resulting in a bright structural blue color in Jiangshan black-bone chickens. In contrast, the low expression of LUM in dark reddish purple (Black group) reduces the reflection of non-iridescent structural colors, making the earlobe color appear almost black, similar to melanin.

An Improved Staging System of Adenoid Cystic Carcinoma in the External Auditory Canal.

The purpose of this study was to define an improved staging system for adenoid cystic carcinoma (ACC) in the external auditory canal (EAC) based on biological behaviors, image findings, and the prognosis of patients with ACC in the EAC. A retrospective study. A single center data. We performed a single-institution retrospective review of 154 patients with ACC in the EAC between January 2004 and September 2021. Risk factors associated with disease-free survival (DFS) and cancer-specific survival (CSS) of ACC in the EAC were identified using univariate and multivariate cox regression analysis. Then an improved staging system was proposed and compared with the Pittsburgh-modified tumor, node, and metastasis (TNM) staging system for statistical differences in DFS and CSS. An improved staging system of ACC in the EAC was defined, in which stage T4 were subclassified into T4a and T4b and were statistically different from the Pittsburgh-modified TNM staging system in DFS and CSS. We also found that the dura mater, facial nerve, sigmoid sinus, deep lobe of parotid gland, and parapharyngeal space involvement were significantly associated with poor prognosis of ACC in the EAC. The improved staging system is more accurate in predicting survival prognosis than Pittsburgh-modified TNM staging system for patients with ACC in the EAC, and may provide more efficient guidance of treatment strategy. The improved staging system of ACC in the EAC is more accurately to predict survival prognosis, and provide guidance of treatment plan than Pittsburgh-modified TNM staging system.

Cytological evaluation, culture and genomics to evaluate the microbiome in healthy rabbit external ear canals.

Lop-eared rabbits may be predisposed to otitis externa (OE) as a consequence of their ear conformation. Although otoscopy, otic cytological evaluation and culture are valuable tools in dogs and cats, published data on rabbits remain lacking. This study aimed to assess the utility of otoscopy and cytological results in evaluating healthy rabbit external ear canals (EECs) and to characterise ear cytological and microbiological findings through culture techniques and metagenomic sequencing. Sixty-three otitis-free client-owned rabbits. All rabbits underwent otoscopy and ear cytological evaluation. In a subset of 12 rabbits, further bacterial and fungal culture, fungal DNA assessment and metagenomic sequencing were performed. Otic cytological results revealed yeast in 73%, cocci in 42.9% and rods in 28.6% of healthy rabbit EECs. Compared to upright-eared rabbits, lop-eared rabbits had more discharge and more bacteria per oil immersion field. Culture isolated eight different species yet metagenomic sequencing identified 36, belonging to the Bacillota (Firmicutes), Pseudomonadota and Actinomycetota phyla. Staphylococcus were the most commonly observed species with both methods. Ten of 12 rabbits were yeast-positive on cytological evaluation with only three yielding fungal growth identified as Yarrowia (Candida) lipolytica, Eurotium echinulatum and Cystofilobasidium infirmominiatum. Healthy rabbit EECs lack inflammatory cells yet can host yeast and bacteria, emphasising the need to evaluate cytological results alongside the clinical signs. Lop-ear anatomy may predispose to bacterial overgrowth and OE. Notably, yeasts may be present despite a negative culture.

Cholesteatoma of the auditory canal complicated by retroauricular abscess

Cholesteatoma of the auditory canal complicated by retroauricular abscess

A meta-analysis comparing the efficacy and safety of different modes of administration of cream in the treatment of otomycosis.

To assess the efficacy and safety of two different modes of administration, external ear canal filling and smearing, in the treatment of otomycosis. A computerised search of relevant published studies in the China National Knowledge Infrastructure, China Biology Medicine, Web of Science, PubMed, Embase and Cochrane Library databases that include randomised controlled trials or clinically controlled trials on the same drug in different modes of administration for the treatment of otomycosis. Seven studies with 934 patients were included. The filled group had a higher clinical efficacy (relative risk = 1.18, 95 per cent confidence interval (CI) 1.12-1.24, p < 0.0001) and a lower recurrence rate (relative risk = 0.29, 95 per cent CI 0.18-0.47, p < 0.0001) compared with the smear group, and there was no significant difference in the adverse effects (relative risk = 0.61, 95 per cent CI 0.34-1.12, p = 0.11). Current evidence suggests that the efficacy of the delivery modality of the external auditory canal filling treatment is significantly better than external auditory canal smearing.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Translabyrinthine and Transcochlear Approaches

Abstract Introduction Skull base neuroanatomy is traditionally learned through two-dimensional anatomical atlases, which while are of unquestionable value, lack the nuanced association of three-dimensional relationships between fundamental anatomical structures relevant to surgical approaches. Surgically focused step-by-step anatomical dissections can augment trainee learning of complex skull base techniques, particularly multistep and nuanced techniques such as translabyrinthine and transcochlear approaches. Methods Translabyrinthine and transcochlear approaches were performed on six sides of three formalin-fixed latex-injected specimens. The study objective was the completion and photo documentation of the steps involved in the approach in order to provide a comprehensive, intelligible, and anatomically oriented resource for multilevel trainees. Illustrative case examples were prepared to supplement approach dissections. Results The translabyrinthine and transcochlear approaches offer unique lateral windows through the temporal bone into the posterior fossa, providing excellent access to pathology at the petrous apex, internal auditory canal, Meckel's cave, and anterolateral brainstem. The transcochlear approach, which is an anterior extension of the translabyrinthine, particularly provides excellent exposure of the prepontine region and clivus. Important surgical considerations include patient position, temporal bone drilling and identification of critical landmarks, dural opening and identification of neurovascular structures, and reconstruction/closure techniques. Conclusion The translabyrinthine and transcochlear approaches are fundamental techniques for lateral skull base and posterior fossa pathologies. Both approaches are hearing-sacrificing but often require minimal to no cerebellar retraction and deliver unique visualization of prepontine neurovascular structures. This step-by-step approach guide provides a unique practical and high-yield surgically oriented learning resource for neurosurgery and otolaryngology trainees.

Recurrent Ear Discharge in Primary Care: Exploring the Possibility of Cholesteatoma - A Case Report

Cholesteatoma is a benign lesion of the keratin-producing squamous epithelium, most commonly arising in the middle ear and mastoid. It is rarely found within the external auditory canal. It presents mainly as unilateral lesions and is often destructive and locally invasive. Hence, early detection and referral to an otorhinolaryngology specialist are warranted due to its grave sequelae. This report is about a rare and atypical case of an external ear canal cholesteatoma (EECC) in a young patient. The diagnosis and referral were delayed due to the nature of the disease that resembles an infection, the rarity and atypical presentation of the case, and a low index of suspicion. Therefore, a high index of suspicion based may lead to a timely diagnosis, management, prevention of serious complications, and optimal preservation of ear function.International Journal of Human and Health Sciences Vol. 08 No. 02 Apr’24 Page: 215-219

Endoscopic Cartilage Modified Inlay Technique With Preserving External Auditory Canal Skin for Repairing Posterior Marginal Perforation.

Objective: To evaluate the graft success rate and hearing gain of endoscopic cartilage myringoplasty with preserving external auditory canal (EAC) skin for posterior marginal perforation. Materials and Methods: We performed a prospective study in 36 patients with posterior marginal perforation who underwent endoscopic cartilage modified inlay technique with preserving EAC skin. Patients were followed up for 12 months. Results: All the 36 patients with unilateral posterior marginal perforation were included in this study. Clinical inosculation of the perichondrium graft and remnant tympanic membrane (TM) occurred at 2 to 3 weeks postoperatively. Simultaneously, neovascularization was initiated at the perichondrium graft. The perichondrium graft had been clinically incorporated to the EAC skin at 2 to 3 weeks postoperatively, which could not be distinguished. At 12 months, residual perforation was seen in inferior margin in one but reperforation was not. The graft success rate was 97.2% (35/36). The mean preoperative air bone gap (ABG) was 29.7 ± 3.8 dB, and the mean postoperative ABG at 12 months was 15.2 ± 3.1 dB; the difference between these values was significant (P < .05; paired-samples t test). The successful surgery rate (postoperative ABG ≤ 20 dB) was 91.7% (33/36). No any intratympanic or EAC cholesteatoma was noted during the follow-up period. Conclusions: Endoscopic cartilage modified inlay technique with preserving EAC skin for repairing posterior marginal perforation is simple and minimally invasive technique, which had shorter operative time, similar graft success rate compared with raising a tympanomeatal flap techniques.

Temporal Bone Fractures and Related Complications in Pediatric and Adult Cranio-Facial Trauma: A Comparison of MDCT Findings in the Acute Emergency Setting.

The purpose of this study was to analyze the prevalence of and complications resulting from temporal bone fractures in adult and pediatric patients evaluated for cranio-facial trauma in an emergency setting. A retrospective blinded analysis of CT scans of a series of 294 consecutive adult and pediatric patients with cranio-facial trauma investigated in the emergency setting was conducted. Findings were compared between the two populations. Preliminary reports made by on-call residents were compared with the retrospective analysis, which was performed in consensus by two experienced readers and served as reference standard. CT revealed 126 fractures in 116/294 (39.5%) patients, although fractures were clinically suspected only in 70/294 (23.8%); p < 0.05. Fractures were longitudinal, transverse and mixed in 69.5%, 10.3% and 19.8% of cases, respectively. Most fractures were otic-sparing fractures (95.2%). Involvement of the external auditory canal, ossicular chain and the osseous structures surrounding the facial nerve was present in 72.2%, 8.7% and 6.3% of cases, respectively. Temporal bone fractures extended into the venous sinuses/jugular foramen and carotid canal in 18.3% and 17.5% of cases, respectively. Vascular injuries (carotid dissection and venous thrombosis) were more common in children than in adults (13.6% versus 5.3%); however, the observed difference did not reach statistical significance. 79.5% of patients with temporal bone fractures had both brain injuries and fractures of the facial bones and cranial vault. Brain injuries were more common in adults (90.4%) than in children (63.6%), p = 0.001. Although on-call residents reliably detected temporal bone fractures (sensitivity = 92.8%), they often missed trauma-associated ossicular dislocation (sensitivity = 27.3%). Temporal bone fractures and related complications are common in patients with cranio-facial trauma and need to be thoroughly looked for; the pattern of associated injuries is slightly different in children and in adults.

Full Recovery of Hearing After Resection of a Large Epidermoid Tumor at the Cerebellopontine Angle: 2-Dimensional Operative Video.

Epidermoid tumors are benign, slow-growing lesions, originating from misplaced ectodermal cells that become trapped during neural tube closure.1 The cerebellopontine angle (CPA) is the most common intracranial location for epidermoid tumors, accounting for approximately 60% of cases.2 Treatment of epidermoid tumors consists of surgical resection, with the goal of gross total resection.3 Here, we describe the case of a patient with a large epidermoid tumor at the CPA causing near-complete hearing loss, who remarkably experienced full recovery of hearing after resection of the tumor. The patient is a 37-year-old woman who presented to our clinic with a CPA tumor causing severe hearing loss consisting of class D hearing and a word recognition score of 5% on audiological examination. Radiographically, the tumor demonstrated significant mass effect on the right cranial nerves VII and VIII with prominent extension into the internal auditory canal. Given the patient's profound hearing loss, she consented to receive a right retrosigmoid craniotomy for resection of the lesion. Although cranial nerves VII and VIII were heavily invested in the tumor, we were able to systematically resect the lesion from the CPA and internal auditory canal, and achieve a gross total resection. Histological examination confirmed the diagnosis of an epidermoid tumor. Remarkably, the patient's audiogram at 3-month follow-up demonstrated complete recovery of hearing in her right ear with a word recognition score of 100% and normal hearing sensitivity across all tested frequencies.

Prımary External Audıtory Canal Cholesteatoma

Abstract External auditory canal (EAC) cholesteatoma is characterized by a bony defect in the auditory canal with a cystic structure lined by keratinizing stratified squamous epithelium and retention of keratin debris. Clinically, patients present with chronic dull pain, otorrhea, or conductive hearing loss. Lamellar keratin debris in a bony defect in the case of an intact tympanic membrane is highly suggestive of external ear canal cholesteatoma. It must be differentiated from keratosis obturans. The locally erosive and indolent nature of cholesteatoma in the bony external ear canal may result in complications due to erosion into adjacent structures such as mastoid cells, semicircular canals, fallopian canal, and temporomandibular joint. The treatment options include conservative therapy and surgery. In this case report, we presented a 75-year-old male with a primary left EAC cholesteatoma underlining the diagnostic and therapeutic features of this rare disease.