Bilateral Oval and Round Window Atresia on CT Temporal Bone: A Rare Anomaly Clinically Mimicking Otosclerosis in an Adult

Symptom: Deafness After Stapedectomy

Isolated oval window atresia (OWA) is a rare cause of congenital conductive middle ear deafness and may be overlooked owing to the normal appearance of the external ear. This anomaly has been previously described, although the published numbers with both imaging and surgical findings are few. Our aim is to correlate the imaging features of OWA with intraoperative findings. This is a single-centre retrospective evaluation of patients who were diagnosed with OWA and who received surgery from January 1999 to July 2006. No new case was diagnosed after 2006 to the time of preparation of this manuscript. High resolution computed tomography (HRCT) imaging of the temporal bones of the patients were retrospectively evaluated by 2 head and neck radiologists. Images were evaluated for the absence of the oval window, ossicular chain abnormalities, position of the facial nerve canal, and other malformations. Imaging findings were then correlated with surgical findings. A total of 9 ears in 7 patients (two of whom with bilateral lesions) had surgery for OWA. All patients had concomitant findings of absent stapes footplate with normal, deformed or absent stapes superstructure and an inferiorly displaced facial nerve canal. HRCT was sensitive in identifying OWA and associated ossicular chain and facial nerve abnormalities, which were documented surgically. OWA is a rare entity that can be diagnosed with certainty on HRCT, best visualised on coronal plane. Imaging findings of associated middle ear abnormalities, position of the facial nerve canal, which is invariably mal-positioned, and associated deformity of the incus are important for presurgical planning and consent.

The purpose of this study is to categorize anomalous tympanic facial nerve (FN) on high-resolution computed tomography (HRCT) and to determinate the significance of associated temporal bone anomalies and congenital syndromes without microtia in patients with hearing loss. A retrospective analysis of HRCT findings in 30 temporal bones in 18 patients with anomalous FN was performed. Abnormalities of the tympanic FN were categorized as follows: category 1: FN medially positioned, but above the oval window; category 2: FN in the oval window niche; and category 3: FN below the oval window. Potential associated findings that were assessed included stapes abnormalities, oval window atresia, and inner ear anomalies, as well as the presence of a known congenital syndrome with hearing loss. The most common type of anomalous tympanic FN was category 1 (67%, n = 20), following by group 2 (20%, n = 6) and group 3 (13%, n = 4). Stapes anomalies were detected in 77% of temporal bones (n = 23), oval window atresia was detected in 43% of temporal bones (n = 13), and inner ear anomalies were detected in 70% of temporal bones (n = 21). Anomalous tympanic facial nerves in temporal bone with conductive hearing loss were often (60%) not associated with oval window atresia. The combination of aberrant tympanic FN and inner ear anomalies was significantly (P = .038) associated with a known congenital syndrome (6 patients), including CHARGE syndrome, oculo-auriculo-vertebral spectrum, Pierre-Robin sequences, and Down syndrome. Therefore, an anomalous tympanic FN in conjunction with inner ear anomalies appears to be a biomarker for certain congenital syndromes with hearing loss in the absence of microtia.

Background: Simple or non-syndromic types of oval window (OW) or round window (RW) atresia are relatively rare in clinical. Few studies have assessed bone conduction (BC) hearing in OW or RW atresia patients, with some reporting that BC hearing lies within the normal range, whereas others observing impaired BC hearing.Aims/Objectives: This study explored the effect of blocking the OW and RW during BC in cat models.Material and Methods: Twenty-four cats were randomly divided into three immobilization groups (OW blockage, RW blockage, and OW + RW blockage) and control group. Each immobilization group also had the initial control state before blockage. Medical adhesive and ear mould glue were used to immobilise the stapes footplate and RW, respectively. Comparisons were made of the auditory brainstem response (ABR) thresholds before and after immobilization for the three immobilization groups during three different stimuli [air conduction (AC) click, BC click, and BC pure tones].Results: The AC click thresholds increased after immobilisation in three experimental groups compared to the control group (p < .05). The AC click thresholds increased compared to their initial control state after all three immobilization groups (p < .05). With an increase in frequency from 2 to 8 kHz, there was a general decrease in the difference between pre- and post-immobilization BC hearing thresholds in all three immobilization groups. The BC click threshold and BC tone thresholds at 2–4 kHz in both OW blockage and OW + RW blockage groups exceeded those in RW blockage group (p < .05).Conclusions and Significance: The use of medical adhesive and ear mould glue for the blockages of OW and RW, respectively in cats was feasible. The effect of blocking the OW and RW in BC hearing was larger at low frequencies than high frequencies between 2 and 8 kHz. OW blockage had a greater effect than RW blockage on BC hearing at 2–4 kHz range.

Oval window atresia (OWA) is a rare otologic condition often associated with a maximal conductive hearing loss, and variable ossicular and facial nerve canal (FNC) anomalies, which have contributed to suboptimal middle ear surgical outcomes. No grading scheme exists to detail the spectrum of associated temporal bone anomalies in OWA; therefore, our objectives were to complete an audiometric and radiographic review to characterize audiometric patterns of hearing loss, and refine the classification system for OWA to determine suitability for middle ear surgery. A retrospective audiometric and radiographic review was conducted at a pediatric tertiary care institution. Patients with OWA identified on temporal bone computerized tomography (CT) scans obtained from 01/2010 to 06/2024 were included. Audiological, radiological, and patient factors were analyzed. Thirty-one patients (48 ears) with OWA were identified. Across frequencies, the air-bone gap decreased significantly as frequency increased (ANOVA with pairwise comparisons, p < 0.001) due to a worsening of bone conduction thresholds and improvement in air conduction thresholds. The FNC was abnormal in 43/48 ears and was determined to overlay the oval window in 6 ears. Additional anomalies included inferiorly displaced, dehiscent, and duplicated canals. Ossicular anomalies were reported in 46/48 ears, and stapedial anomalies were most common. Our findings indicate OWA may manifest audiometrically with consistent and specific hearing loss characterized by a 60-80 dB ABG at lower frequencies that decreases above 2 kHz. CT findings of OWA show considerable variability. We propose a new classification system for OWA based on facial nerve position as this directly influences middle ear surgical feasibility.

Objective: To analyze the clinical characteristics and appropriate surgical procedures, and discuss the classification of congenital middle ear malformation. Methods: All cases were from the Center of Otorhinolaryngology, the Sixth Medical Center of Department of PLA General Hospital. All of these cases, including 26 male patients (ears) , 10 female patients (11 ears) , aged from 7 to 57 years old, had normal external auditory canal, tympanic membrane, conductive hearing loss, type A tympanogram and negative Gelle's test. Tympanoplasty was performed in all cases. The deformity was classified to three types,i.e., Type I (stapes foot plate mobility): Ⅰa, ossicular chain deformity with normal stapes suprastructure; Ⅰb, ossicular chain deformity with abnormal stapes suprastructure; Type Ⅱ (stapes foot plate fixation): Ⅱ a,normal ossicular chain, Ⅱ b, ossicular chain malformation; and Type Ⅲ: vestibular window osseous atresia or undeveloped, or with round window atresia. The malformation of type Ⅱ and Ⅲ may be accompanied with abnormal facial nerve. In addition, the papers on middle ear malformation published from 1982 to 2017 were analyzed retrospectively. The clinical data of 451 ears malformation were summarized. Results: According to the revisional classification criteria in 37 ear samples from our hospital, 20 ears were type I. 6 type Ⅰa cases were used PORP (partial ossicular replacement prosthesis) to reconstruct the ossicular chain; 14 type Ⅰb cases were used TORP (total ossicular replacement prosthesis) to reconstruct the ossicular chain. For the 5 ears of type Ⅱ, 2 of which were type Ⅱ a and 3 were type Ⅱ b. 4 ear samples of type Ⅱ were implanted with Piston ossicular prosthesis, 1 was implanted with TORP in which the ossificated foot plate was removed with periosteum preserved. 12 ear samples were type Ⅲ, with vestibular window osseous atresia, facial nerve malformation, and stapes suprastructure malformation. The pistons ossicular prosthesis were implanted in vestibular window in 3 ears with facial nerve covering vestibular window partially. The surgery had to be given up in 5 ears, and TORP was implanted in 4 ears at the opening with preserved periosteum at the beginning of the tympanic scala because of facial nerve covering vestibular window totally. 30 ears with complete follow-up data had no sensorineural hearing loss and the average air-bone conduction decreased 23.3±10.7 dB (P<0.05).There were 234 ears of type Ⅰ in 451 ears of congenital middle ear malformation reported in the literature. 113 of which were type Ⅰa, the basic surgery was ossicular chain shaking and artificial or autogenous PORP implantation. Type Ⅰb was 121 ears, with autogenous or artificial TORP and PORP. Type Ⅱ was125 ears, including type Ⅱa 22 ears, Ⅱb 60 ears, and no subclassification for 43 ears. The surgery of type Ⅱ was the same as otosclerosis. The vestibular window atresia of type Ⅲ was 92 ears, the surgery of 17 ears had to be abandoned, the other ears underwent vestibular window, promontory or semicircular canal opening to reconstruct hearing with Piston, autogenous or artificial TORP. Conclusion: Referring to the classification of congenital middle ear malformation combining with appropriate surgical materials and methods, otologists can better understand and choose appropriate surgical method to the middle ear malformation.

The sound stimulus received by the pinna is transmitted to the oval window of the inner ear via the outer ear and middle ear. Assuming that the perilymph in the scala vestibuli and scala tympani is compressible, we report that the sound wave generated in the cochlea due to the vibration of the oval window can be expressed by the combination of even and odd symmetric sound wave modes. Based on this new approach, this paper studies the cause of hearing deterioration in the lower frequency region seen in round window atresia from the viewpoint of cochlear acoustics. Round window atresia is an auditory disease in which the round window is ossified and its movement is restricted. Using the finite element method, a round window atresia model was designed and the acoustic behavior of the round window was discussed corresponding to the level of disease. From this, we report that the healthy round window works as a free-end reflector to the incident sound waves, but it also works as a fixed-end reflector in the case of round window atresia. Next, we incorporated the round window atresia model into a cochlear model and performed a simulation in order to determine the acoustic aspects of the cochlea as a whole. The simulation results indicate that hearing deterioration occurs in a lower frequency range, which is also coincident with the clinical reports (hearing deterioration of approximately 10 to 20 dB below 4000 Hz). Finally, we explain that the cause of hearing deterioration due to round window atresia is considered to be the even sound wave mode enlarging due to the fixed-end reflection at the ossified round window, and, as a result, the odd sound wave mode that generates the Békésy’s traveling wave on a basilar membrane is significantly weakened.

Symptom: Conductive Hearing Loss after Cholesteatoma Surgery

A 28-year-old man presented with right-sided facial paralysis that had been worsening over the past eight months. He was initially diagnosed with Bell's palsy and treated with oral steroids and antiviral medication immediately after symptom onset, but experienced minimal improvement. He has a known history of conductive hearing loss in the right ear since age five due to a traumatic tympanic membrane perforation from q-tip use and subsequently underwent tympanoplasty at that time. He denied otalgia, otorrhea, vertigo, or tinnitus. Physical examination showed grade 6/6 paralysis on the right side. Audiogram from two months before presentation ago is shown in Figure 1. What is your diagnosis?Figure 1: Audiogram showing moderate-to-severe conductive hearing loss on the right side. Hearing loss, paralysis.Figure 2: Axial (horizontal) CT of the right temporal bone showing the cholesteatoma involving the middle ear, cochlea, and internal auditory canal. Hearing loss, paralysis.Figure 3: Axial (horizontal) CT of the right temporal bone showing cholesteatoma 1.2 mm above Figure 2 showing the involvement of the tympanic (middle ear) facial nerve by the cholesteatoma. Hearing loss, paralysis.Figure 4: Coronal (vertical parallel to ear) CT of the right temporal bone demonstrating that the cholesteatoma has eroded the tegmen tympani. The cholesteatoma appears to have originated medial to the malleus. Hearing loss, paralysis.Figure 5: Sagittal (vertical parallel to face) CT of the right temporal bone further highlighting the erosion of the tegmen tympani as the cholesteatoma extended medially to the cochlea and internal auditory canal. Hearing loss, paralysis.Figure 6: Sagittal (vertical parallel to face) CT Temporal bone showing the involvement of the cochlea 2 mm medial to the image in Figure 5. Hearing loss, paralysis.DIAGNOSIS: IATROGENIC CHOLESTEATOMA The most concerning aspect of this patient's presentation is the duration of his facial paralysis. Although Bell's palsy is the most frequent diagnosis for facial paralysis, the physician must begin to consider other etiologies and obtain imaging with MRI of the internal auditory canals (IACs) if the paralysis persists beyond six months. The majority of patients with facial paralysis are diagnosed with Bell's palsy, also called idiopathic facial nerve paralysis. By definition, the exact cause of Bell's palsy is unknown; however, it is believed that a large number of cases are due to edema in and around the facial nerve and is caused by the herpes simplex virus (HSV). HSV, which also causes cold sores, has been found to be present within the geniculate ganglion of affected individuals. Viral replication and reactivation within the ganglion are thought to cause edema and subsequent compression of facial nerve fibers, resulting in blockage of electrical conduction and subsequent facial paralysis. The surrounding bony architecture of the facial nerve helps to explain this phenomenon. As it courses through the labyrinthine segment of the temporal bone (the narrowest portion of the fallopian canal measuring approximately 0.68 mm), the facial nerve is completely surrounded by bone, and therefore vulnerable to compression in the event of swelling. The extent of nerve injury depends on both the degree of inflammation and how quickly treatment with steroids and antivirals can be given to reduce swelling. In cases of mild edema, there is transient compression and blockage of nerve conduction until the inflammation subsides. However, in more severe cases the nerve fibers may be crushed and rapidly degenerate. In these cases, axon regeneration usually occurs, but the new nerve fibers may not reach the intended target muscles. This results in synkinesis, in which voluntary movement in one facial muscle group causes involuntary activity of another. For example, a patient may experience involuntary blinking when trying to smile. In the case of this patient, we obtained a CT scan of the temporal bones given the history of conductive hearing loss and previous surgery (Figs. 2, 3, 4, 5). On the right side, we see bony erosion with soft tissue opacification within the petrous and mastoid temporal bone segments, including regional involvement of the labyrinthine and tympanic segments of the facial nerve, basal turn of the cochlea, vestibule, IAC, tegmen tympani, and middle ear cavity including the ossicles. Though initially treated for Bell's palsy, our patient was ultimately diagnosed with a middle ear cholesteatoma that invaded the skull base and involved the facial nerve. The diagnosis was confirmed surgically. Cholesteatomas are benign masses comprised of abnormal squamous epithelium within the temporal bone. Over time, these masses can grow large enough to cause local bony destruction with surrounding inflammation and granulation tissue. Cholesteatomas are often classified into congenital and acquired types (primary or secondary). In the primary acquired type, cholesteatomas typically arise in the setting of chronic tympanic membrane (TM) retraction. Alternatively, secondary acquired cholesteatomas occur in the setting of TM perforation with epithelial migration into the middle ear space. Given the patient's history of q-tip injury and subsequent surgery, the cholesteatoma was most likely caused by traumatic implantation of squamous epithelium or iatrogenic, i.e., caused by the surgeon not removing or implanting squamous epithelium from the middle ear. Facial nerve palsy due to cholesteatoma has been rarely reported in the literature.1 While the mechanism by which cholesteatoma causes facial nerve palsy remains unclear, several theories have been proposed. The first hypothesis is that direct compression by the cholesteatoma is responsible for causing nerve edema and subsequent ischemia. A second hypothesis is that direct contact between the cholesteatoma and facial nerve promotes an inflammatory reaction that leads to injury. This theory is supported by histological studies showing degeneration of the epineurium in facial nerve segments exposed to cholesteatoma or granulation tissue.2 A third hypothesis is that nerve injury is mediated by neurotoxic or enzymatic substances secreted by the cholesteatoma, although the significance of these factors remains controversial.3 It is important to accurately diagnose and treat cholesteatomas, as they have a strong propensity to become infected and erode through local bony structures.4 The infections and associated pathogens in cholesteatoma can be especially hard to eradicate as they are frequently polymicrobial and resistant to antibiotics. Skull base invasion of cholesteatomas carries an increased risk of deafness, facial paralysis, and intracranial complications given their location. In this patient, we see the cholesteatoma is already eroding the cochlea, creating an increased likelihood of sensorineural hearing loss in the right ear. After evaluating the extent of the disease on CT scan, surgical treatment is undertaken with the goals of removing all of the cholesteatoma and repairing damaged structures when possible. Various surgical approaches can be used, depending on the involved structures as well as surgeon comfort level. In this patient, a right middle cranial fossa or translabyrinthine approach could be undertaken. Generally, when the hearing is intact, the best approach is the middle cranial fossa. The translabyrinthine approach is reserved for non-serviceable hearing patients. If the facial nerve function does not return, the patient may receive a hypoglossal-facial jump graft. In the future, a medical device in development may allow restoration of function for the patient.5-6 BONUS ONLINE VIDEOS: VISUAL DIAGNOSIS Read this month's Clinical Consultation case, then watch the accompanying videos from Hamid R. Djalilian, MD, to review the patient's imaging for yourself. Video 1. Axial (horizontal) CT of the right temporal bone showing the extent of the cholesteatoma in the axial plane and involvement of tympanic facial nerve and geniculate ganglion. Video 2. Coronal (vertical parallel to ear) CT of the right temporal bone showing the extent of the cholesteatoma in the coronal plane and invasion of the tegmen and IAC. Video 3. Sagittal (vertical parallel to face) CT of the right temporal bone showing the extent of the cholesteatoma in the sagittal plane and invasion of the cochlea. Video 4. Axial (horizontal) CT of the left temporal bone showing the normal anatomy of the facial nerve in the axial plane. Video 5. Coronal (vertical parallel to ear) CT of the left temporal bone showing the normal anatomy of the tegmen tympani. Video 6. Sagittal (vertical parallel to face) CT of the left temporal bone showing the normal cochlear anatomy in the sagittal plane. Watch the patient videos online at thehearingjournal.com

Oval window atresia: A novel surgical approach and pathognomonic radiological finding

Semicircular canal dehiscence: Frequency and distribution on temporal bone CT and its relationship with the clinical outcomes

Branchio-oto-renal syndrome (BOR) is an autosomal dominant mutation of the EYA1 and the more recently discovered the SIX1 gene.1 The phenotype and syndrome were comprehensively described by Melnick in 1975 to include hearing loss, auricular malformations, branchial arch remnants, and renal anomalies.2 The diagnosis of BOR is made using major and minor criteria as defined by Chang et al 2004.3 However, 60% of patients who meet phenotypic criteria do not have an identifiable mutation in the EYA1 gene, leading to recent interest in the EYA-SIX regulatory system.1 The most common manifestations include hearing loss (98.5%), preauricular pits (83.6%), branchial anomalies (68.5%), renal anomalies (38.2%), and external ear abnormalities (31.5%). In terms of the imaging characteristics, the most sensitive modality remains CT of the temporal bones. The most commonly reported anomalies on temporal bone imaging include but are not limited to 1)hypoplastic apical turn of the cochlea, 2) facial nerve deviated to the medial side of the cochlea, 3) funnel-shaped internal auditory canal, and 4) patulous eustachian tube. 4 The spectrum of hearing loss in BOR is variable but most commonly presents with mixed hearing loss (50%), pure sensorineural hearing loss (25%) and pure conductive hearing loss (25%) 5. The conductive component of the hearing loss is most often the result of ossicular chain abnormalities. A 42 year old male previously diagnosed with BOR using clinical criteria presented with a conductive hearing loss. His physical exam demonstrated small external auditory canals with a normal tympanic membrane. His audiogram demonstrated a mild left sensorineural hearing loss and a maximal conductive hearing loss in the right ear. Imaging with CT revealed several findings consisted with BOR: Bilateral enlarged air-filled eustachian tubes extending from the middle ear to the nasopharynx, a widened and flared internal acoustic meatus with the nervus intermedius extending into a funnel shaped labyrinthine segment of the temporal bone and hypo-plastic horizontal canal, hypo-plastic vestibular system/epitympanum, and lateral position of the facial nerve. The incus and malleus were malformed and fixed in the attic (Fig. 1). Figure 1 Computed tomography (CT) images. Panel A: Axial view of the head demonstrating enlarged eustachian tubes (arrow). Panel B: Axial view of right internal auditory (IAC) canal demonstrating hypoplastic horizontal semicircular canal(H), and funnel shaped ... Despite the findings on CT, the patient elected to pursue a middle ear exploration prior to pursuing other rehabilitative options. At surgery, middle ear exploration revealed a very small oval window niche with no clear oval window, or stapes footplate as shown on this view with a 30° endoscope (Fig. 2). The round window niche was visible. A dehiscent facial nerve was visible at the horizontal segment. Because no mobile footplate was found there was no attempt at ossiculoplasty. The patient recovered from surgery with no change in his hearing and later went on to a Baha which he found beneficial. Figure 2 Right middle ear as viewed through a 30° endoscope during surgery. There was no clear stapes footplate, but a narrow oval window (OW) niche. The round window (RW) niche was visible. The OW and RW are labeled to the right above the structures. ... The extreme ossicular abnormalities in this patient with BOR made his maximal conductive hearing loss not amenable to ossiculoplasty. We ultimately failed in our attempt to restore his conductive hearing loss due to agenesis of the oval window and lack of a mobile footplate. The intraoperative endoscopy revelaed the lack of suitable anatomy for an ossicular replacement prosthesis. The findings in our patient highlight the diagnostic findings in BOR on CT scan of the temporal bone and correlate well with his clinical findings. Although BOR patients may not be a homogeneous in terms of their middle ear anatomy, this patient suggests ossiculoplasty may not be a viable option in this population.

Objective: To summarize the clinical features and postoperative efficacy of patients with oval window atresia accompanied by facial nerve aberration. Methods: The clinical data of patients with congenital middle ear malformation with facial nerve aberration admitted to our hospital from January 2015 to March 2023 were retrospectively analyzed. There were 97 cases (133 ears) in total. Among them, 39 patients (44 ears) had complete follow-up data, including 27 male patients and 12 females, aged 7-48 years old, with an average age of 17.8 years old. Of these, 14 cases (16 ears) were patients combined with facial nerve aberration, and 25 cases (28 ears) were without facial nerve aberration. The results of imaging examination, pure-tone audiometry, selection of surgical strategy, intraoperative findings and postoperative hearing improvement were summarized and analyzed. The malformations of malleus, incus, stapes, oval window and facial nerve were recorded. Prism 9 software was used to statistically analyze the mean bone conductance and air-bone gap of patients before and after surgery. Results: All the 14 patients (16 ears) with middle ear malformation accompanied by facial nerve aberration and oval window atresia showed poor hearing and no facial palsy since childhood. High resolution CT (HRCT) examination of temporal bone, pure tone audiometry and Gelle test were performed before surgery. The malformations of malleus, incus, stapes, oval window and facial nerve were recorded. Preoperative high-resolution CT (HRCT) examination of temporal bone found 12 ears with 4 or more deformities, accounting for 75.00%, in the group of patients with facial nerve malformation. The preoperative average bone conductive threshold was (15.3±10.4) dB and the average air-bone gap was (46.3±10.6) dB in pure-tone audiometry (0.5, 1, 2, 4kHz). According to the different degrees of facial nerve and ossicle malformation, we performed three different hearing reconstruction strategies for the 14 patients (16 ears) with facial nerve aberration and oval window atresia, including 7 ears of incus bypass artificial stape implantation, 7 ears of Malleostapedotomy (MS) and 2 ears of Malleus-cochlear-prothesis (MCP). After 3 months to 18 months of follow-up, all patients showed no facial paralysis. The postoperative mean bone conductive threshold was (15.7±7.9) dB and air-bone gap was (19.8±8.5) dB. There were significant differences in mean air-bone gap before and after operation (t=7.766, P<0.05), and there was no significant difference between the mean bone conductive threshold before and after surgery (t=0.225, P=0.824). There was no significant difference of mean reduction of air-bone gap between patients with and without facial nerve aberration (t=1.412, P=0.165). There was no significant difference between the three hearing reconstruction strategies. There was no significant displacement of the Piston examined by U-HRCT. Conclusion: For patients of middle ear malformation whose facial nerve cover the oval window partially, incus bypass artificial stape implantation or Malleostapedotomy (MS) can be selected according to the specific condition of auditory ossis malformation, and for patients whose facial nerve completely covers the oval window area, Malleus-cochlear-prothesis (MCP) can be selected. Three types of stapes surgery are safe and reliable for patients with oval window atresia accompanied by facial nerve aberration. There was no significant difference in efficacy between them. Preoperative HRCT assessment of middle ear malformation is effective. There is no significant difference of surgical effect with or without facial nerve aberration. The U-HRCT can be used to evaluate the middle ear malformation before surgery and the Piston implantation status after surgery. Due to the risks of surgery, those who do not want to undergo surgery can choose artificial hearing AIDS, such as hearing aid, vibrating soundbridge, bone bridge or bone-anchored hearing aid.

Background: The persistent stapedial artery (PSA) is a rare congenital vascular malformation involving the middle ear. It is usually associated with pulsatile tinnitus and/or conductive hearing loss and can account for multiple risks during middle ear surgery. Case Report: we present a case of a 9-year-old male child with conductive hearing loss and persistent stapedial artery in his right ear, who was admitted to our ENT Department for hearing loss. During surgery, we discovered PSA along with congenital stapes agenesis and oval window atresia, as well as an abnormal trajectory of the mastoid segment of the facial nerve. After ossicular reconstruction (transcanal total ossicular replacement prosthesis) with cochleostomy, no surgical complications were recorded and hearing improvement was monitored by pre- and postoperative audiometry. Conclusion: Stapedial artery is a rare anatomical middle ear abnormality that can prevent proper surgical hearing restoration and can be associated with other simultaneous temporal bone malformations.

Summary Only a few cases of a round windows atresia have been reported in the literature so far. The dia gnosis is based on the preoperative CT scan and local fi ndings during a middle ear exploration. The complete round window closure leads to a signifi cant conductive hearing loss. The hearing test result might be similar to the one found in otosclerosis. We report a case of 30-year-old woman, who previously underwent three surgeries for suspected otosclerosis without any hearing improvement. A round window atresia was only identified during following revision surgery, as well as a missing stapedial muscle, an abnormal shape and movement of the stapes footplate. In order to achieve a functional inner ear hydrodynamics, a cochlear fenestration was performed. Although there was a signifi cant improvement in the cochlear reserve at speech frequencies after the operation, the patient didn’t report any hearing improvement. Although otosclerosis may be considered as a cause of the conductive hearing loss preoperatively, rare dia gnoses should not be neglected. The aim of this case report is to share the experience and highlight mistakes made. After each unsuccessful stapedoplasty with unsatisfying hearing gain, a high resolution CT should be performed to exclude third window syndrome or another rare abnormality. Key words atresia – cochlear fenestration – round window – stapes surgery