Distinguishing Audiometric and Radiographic Features of Oval Window Atresia.

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.

The patient’s imaging features, especially the honeycomb pattern of ossific changes in the geniculate fossa, were virtually pathognomonic for ossifying hemangioma of the facial nerve.

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.

What's Your Diagnosis? Symptoms: Middle Ear Mass and Unilateral Hearing Loss

Objective: To conclude the clinical features and the postoperative efficacy of congenital middle ear malformation treated with Malleostapedotomy (MS), and to explore the security and effectiveness of MS surgery. Methods: The clinical data of 17 patients (18 ears) with congenital middle ear malformation undergoing MS procedure were analyzed. There were 10 males (11 ears) and 7 females (7 ears), aged from 7 to 48 years. The imaging examination, pure-tone audiometry, intraoperative findings and postoperative hearing improvement of these patients were analyzed and summarized, and software SPSS23.0 was used for statistical analysis. Rusults All the 17 patients (18 ears) presented with hearing loss since childhood on the affected sides. Preoperative high resolution CT (HRCT) of the temporal bone revealed definite malformations in 9 ears (6 ears with incus long process dysplasia and 3 ears with anterior and posterior crus dysplasia). Before surgery, the mean bone conductive hearing threshold at 500, 1 000, 2 000 and 4 000 Hz was (15.6±10.2) dB HL, the mean air conductive hearing threshold was (60.6±9.7) dB HL, and the mean air-bone gap was (45.0±8.9) dB. During the surgery, all 18 ears were found to be accompanied by absence or hypoplasia of incus long process. 12 ears had stapes fixation, 6 ears had oval window atresia. All patients were treated with MS procedure by using Piston. The patients were followed up for 3 months to 1 year. The mean bone conductive hearing threshold was (14.7±8.8) dB HL. The mean air conductive hearing threshold was (37.7±11.6) dB HL, and the mean air-bone gap was (23.0±8.0) dB. There were statistically significant differences in the mean air conductive hearing threshold and mean air-bone gap before and after surgery (P<0.05). While there were no statistically significant differences in the mean bone conductive hearing threshold before and after surgery (P=0.550). Conclusions: MS procedure is safe and reliable in patients with congenital middle ear malformation of incus long process dysplasia, stapes fixation or oval window atresia. HRCT is useful in evaluating the major deformity of ossicular chain and facial nerve deformity. However, it is not enough to evaluate the joint of incus-stapes and oval window atresia. MS surgery in middle ear malformation requires advanced surgical experience and skills. The hearing improvement can be significant, even though some air-bone gap after surgery exist.

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.

Oval window atresia is often accompanied by malpositioned facial nerve, when inferiorly located facial nerve occupies the expected site of oval window, the ossicular chain reconstruction will always be abandoned. We report the case of a 12-year-old boy with one-side middle ear deformity and hearing loss. Under surgical exploration, the tympanic segment of facial nerve occupied the entire atresia plate, we created a hole on the bony basal turn of the cochlear immediately above the round window, a hand modeled titanium stapes prosthesis was used between the handle of malleus and cochleostomy opening. The audiogram showed an average hearing improvement of 36 dBHL three months later postoperatively. For the case with oval window atresia and inferiorly located facial nerve, cochleostomy could be an effective alternative fenestration site for ossicular chain reconstruction. The prosthesis shaping is always needed for better sound conduction.

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

McRackan, Theodore R.; Carlson, Matthew L.; Reda, Fitsum A.; Noble, Jack H.; Rivas, Alejandro Author Information

The purpose of this study is to offer new data about facial nerve malformations in the tympanic cavity. Prospective anatomic study of newborns to demonstrate the submacroscopic anatomy of the intratympanic facial nerve and its surrounding structures by malformations. Step-by-step microdissection of 12 newborn temporal bones and histologic evaluation of 4 middle ears showing multiple malformations. Four of 12 temporal bones presented malformation in the middle ear. All 4 temporal bones showed developmental failures of the stapes, and 3 of them had malposition of the tympanic portion of the facial nerve. In 3 cases, there was an oval window atresia, and in 1 case, the rim of the oval window was not ossified and was positioned medial to the stapes. Malformation or displacement of the stapes can be an indirect sign for facial nerve malformation. The most common site for facial nerve malformation is the tympanic portion. The tympanic segment of the nerve is devoid of bony covering in association with these anomalies of the stapes.

Symptom: Postauricular Mass

Symptoms: Unilateral Hearing Loss and Facial Paresis

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.

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