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The auditory ossicles amplify and transmit sound from the environment to the inner ear. The distribution of bone mineral density is crucial for the proper functioning of sound transmission as the ossicles are suspended in an air-filled chamber. However, little is known about the distribution of bone mineral density along the human ossicular chain and within individual ossicles. To investigate this, we analyzed fresh-frozen human specimens using synchrotron-based phase-contrast microtomography. In addition, we analyzed the volume and porosity of the ossicles. The porosity for the auditory ossicles lies, on average, between 1.92% and 9.85%. The average volume for the mallei is 13.85 ± 2.15 mm 3 , for the incudes 17.62 ± 4.05 mm 3 and 1.24 ± 0.29 mm 3 for the stapedes. The bone density distribution showed a similar pattern through all samples. In particular, we found high bone mineralization spots on the anterior crus of the stapes, its footplate, and along areas that are crucial for the transmission of sound. We could also see a correlation between low bone mineral density and holey areas where the bone is only very thin or missing. Our study identified a similar pattern of bone density distribution within all samples: regions exposed to lower forces generally show higher bone density. Further, we observed that the stapes shows high bone mineral density along the anterior crus and its footplate, which may indicate its importance in transmitting sound waves to the inner ear., (© 2024. The Author(s).)

Objective: To summarize the HRCT and MRI appearances of stapical footplate fistula related to inner ear malformation (SFF-Re-IEM). Methods: The HRCT and MRI materials of 48 cases (53 ears) SFF-Re-IEM were retrospectively analyzed. Among them, 25 SFF-Re-IEM ears were confirmed by surgery. Their CT and MRI findings including associated IEM type, internal auditory canal (IAC) malformation, tympanic fluid, its density and signal features, and accompanied labyrinthitis were recorded. Results: Among 48 cases (53 ears) with SFF-Re-IEM, 17 ears with incomplete partition type Ⅰ, accounting for 32.1%, 13 ears with common cavity for 24.5%, 13 ears with cochlear aplasia for 24.5%, 7 ears with cochlear dysplasia Ⅱ for 13.2%, and 3 ears with Mondini for 5.7%,were found respectively. 94.3% of them were associated with a defect or dysplasia in the found of the IAC. They were divided into 4 types according to the intact of the stapical footplate and accompanied CSF otorrhea: 22 ears were diagnosed as the stapical footplate leaking, of them, 2 ears might come from the stapical footplate bony defect, 6 ears were from the stapical footplate hernia. 1 ear belonged to the peristapical footplate leaking. 30 ears with the isolated the stapical footplate hernia were another found. The bony defect in 2 ears with the stapical footplate bony defect were not presented on CT and MRI.The focal bony defect of the affected stapical footplate of 36 ears with the stapical footplate hernia were demonstrated, which presented the hemispherical protruding into the tympana, the soft-tissue density on CT, and CSF-like signal on the MR heaved-T2WI images. Among 22 ears with the stapical footplate leaking, their imaging appearances varied from the different amount of the leaking CSF. Besides the focal bony defects of the affected stapical footplates, there were much more CSF-like density or signal in the ipsilateral tympanic cavity in 17 affected ears connecting with the vestibule through the defect area. In the CSF leaking ears with less CSF leaking in 5 ears, the CSF-like cysts like SFH were shown on the stapical footplate defect area, but their outer edges were irregular, and the CSF-like signal scattering in the tympanic cavity did not connect with the protruding cysts at the stapical area. Conclusion: The variable appearances of the SFF-Re-IEM ears based on the different subtypes are its characteristic HRCT and MRI appearances. This is helpful for the SFF-Re-IEM diagnosing to grasp its imaging features.

Purpose: The purpose of this study was to evaluate the ability of ultra-high-resolution computed tomography (UHR-CT) to assess stapes and chorda tympani nerve anatomy using a deep learning (DLR), a model-based, and a hybrid iterative reconstruction algorithm compared to simulated conventional CT., Materials and Methods: CT acquisitions were performed with a Mercury 4.0 phantom. Images were acquired with a 1024 × 1024 matrix and a 0.25 mm slice thickness and reconstructed using DLR, model-based, and hybrid iterative reconstruction algorithms. To simulate conventional CT, images were also reconstructed with a 512 × 512 matrix and a 0.5 mm slice thickness. Spatial resolution, noise power spectrum, and objective high-contrast detectability were compared. Three radiologists evaluated the clinical acceptability of these algorithms by assessing the thickness and image quality of the stapes footplate and superstructure elements, as well as the image quality of the chorda tympani nerve bony and tympanic segments using a 5-point confidence scale on 13 temporal bone CT examinations reconstructed with the four algorithms., Results: UHR-CT provided higher spatial resolution than simulated conventional CT at the penalty of higher noise. DLR and model-based iterative reconstruction provided better noise reduction than hybrid iterative reconstruction, and DLR had the highest detectability index, regardless of the dose level. All stapedial structure thicknesses were thinner using UHR-CT by comparison with conventional simulated CT (P < 0.009). DLR showed the best visualization scores compared to the other reconstruction algorithms (P < 0.032)., Conclusion: UHR-CT with DLR results in less noise than UHR-CT with hybrid iterative reconstruction and significantly improves stapes and tympanic chorda tympani nerve depiction compared to simulated conventional CT and UHR-CT with iterative reconstruction., Competing Interests: Declaration of competing interest Two authors in this work, A.B. and P.A.G.T., are involved in a non-remunerated research contract with Canon Medical Systems. K. H. works as a CT clinical research scientist for Canon Medical Systems Corporation., (Copyright © 2024 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.)

Background, Aims: Stapes footplate thickness measurement using ultra-high-resolution CT has been described only in the lateral semicircular canal plane. The purpose of this study was to compare stapes footplate thickness between the lateral semicircular canal and stapes axial planes in patients with otosclerosis compared to controls., Material and Methods: We performed a retrospective single-center study of patients undergoing high-resolution temporal bone CT. Two radiologists measured stapes footplate thickness in both the lateral semicircular canal and stapes axial planes., Results: Between February 2020 and October 2022, we collected 81 ears from 49 patients (75% of women; mean age 51.22 ± 16.6 years, 17 otosclerosis, and 64 controls). In the stapes axial plane, there was a significant anterior thickening in otosclerosis patients (Reader 1: 0.52 ± 0.12 [0.3-0.7] vs. 0.41 ± 0.08 [0.3-0.6], p  = 0.001; Reader 2: 0.54 ± 0.06 [0.5-0.7] vs. 0.39 ± 0.08 [0.2-0.6], P  < 0.001) compared to controls. These differences were not significant using the lateral semicircular canal plane., Conclusion: The stapes footplate was thickened at its AC in otosclerosis patients using only the stapes axial plane., Significance: We propose to use the stapes axial plane instead of the lateral semicircular canal plane when analyzing the stapes.

Introduction: Congenital ossicular chain anomalies are rare conductive hearing loss conditions that remain difficult to diagnose even with high-resolution computed tomography (CT). The preoperative diagnosis is helpful for surgical planning and counseling patients regarding treatment outcomes., Case Presentation: We report a case involving a 14-year-old boy presenting with left conductive hearing loss without history of trauma for 5 years, physical examination showed normal otoscopic examination bilaterally and high-resolution CT showed absent of stapes suprastructure and footplate. Subsequent diagnosis was done via endoscopic middle ear exploration which revealed an absent long process of the incus, stapes suprastructure and footplate, but with intact oval window membrane. The residual incus was removed, and a tragal perichondrium graft was used over the oval window. A total ossicular replacement prosthesis was placed between the malleus and oval window to repair the chain. Postoperatively, the patient had no complications. Preoperative pure tone average revealed an air/bone result of 52/8 dB. Follow-up after surgery at 6 months showed a pure tone average air/bone result of 15/3 dB. The air-bone gap was reduced from 44 to 12 dB., Conclusion: Congenital absence of the stapes suprastructure and footplate remains a rare condition compared to the myriad of middle ear anomalies in the literature., (© 2024 S. Karger AG, Basel.)

Purpose: Imaging diagnosis of stapes fixation (SF) is challenging owing to a lack of definite evidence. We developed a comprehensive machine learning (ML) model to identify SF on ultra-high-resolution CT., Materials and Methods: We retrospectively enrolled 109 participants (143 ears) and divided them into the training set (115 ears) and test set (28 ears). Stapes mobility (SF or non-SF) was determined by surgical inspection. In the ML analysis, rectangular regions of interest were placed on consecutive axial slices in the training set. Radiomic features were extracted and fed into the training session. The test set was analyzed using 7 ML models (support vector machine, k nearest neighbor, decision tree, random forest, extra trees, eXtreme Gradient Boosting, and Light Gradient Boosting Machine) and by 2 dedicated neuroradiologists. Diagnostic performance (sensitivity, specificity and accuracy, with surgical findings as the reference) was compared between the radiologists and the optimal ML model by using the McNemar test., Results: The mean age of the participants was 42.3 ± 17.5 years. The Light Gradient Boosting Machine (LightGBM) model showed the highest sensitivity (0.83), specificity (0.81), accuracy (0.82) and area under the curve (0.88) for detecting SF among the 7 ML models. The neuroradiologists achieved good sensitivities (0.75 and 0.67), moderate-to-good specificities (0.63 and 0.56) and good accuracies (0.68 and 0.61). This model showed no statistical differences with the neuroradiologists (P values 0.289-1.000)., Conclusions: Compared to the neuroradiologists, the LightGBM model achieved competitive diagnostic performance in identifying SF, and has the potential to be a supportive tool in clinical practice., (© 2023. The Author(s) under exclusive licence to Japan Radiological Society.)

Purpose: This study aimed to propose a radiological classification of the incudo-stapedial angle by preoperative high-resolution computed tomography (HRCT) images and to highlight its importance for predicting the use of reversal-steps stapedotomy (RSS) rather than the traditional non-reversal technique., Methods: We included 83 candidates for stapedotomy operation. Two physicians measured the radiological incudo-stapedial joint angle in the preoperative HRCT. According to this measurement, the radiological incudo-stapedial joint was classified into three types: obtuse, right, and acute. In addition, this radiological classification was correlated with the intraoperative use of the stapedotomy technique, either reversal or non-reversal., Results: The RSS technique was used in forty-two (97.7%) cases with an obtuse angle and twenty-six (89.7%) with a right angle. At the same time, the traditional non-reversal technique was used in all patients with an acute angle. The three groups differed significantly regarding the method used for stapedotomy (P value < 0.001). Moreover, Spearman's correlation coefficient revealed a significant correlation between the used technique and the radiological type of the incudo-stapedial angle (P value < 0.001)., Conclusions: This prospective study proposed a preoperative radiological classification of the incudo-stapedial angle. This classification was significantly correlated with the type of stapedotomy technique. The RSS technique was feasible in most cases with an obtuse and right radiological incudo-stapedial angle. In contrast, the non-reversal method was used in all patients with an acute radiological incudo-stapedial angle. This radiological classification could predict the choice for the stapedotomy technique with an accuracy of 95.18%, a sensitivity of 73.33%, and a specificity of 100%., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Congenital absence of the stapedial tendon is a rare entity with characteristic imaging findings, which can go unrecognized due the scarcity of the diagnosis and limited previous description in the imaging literature. We aim to characterize the imaging features of this entity., Methods: A series of 9 cases with surgical confirmation of stapedial tendon absence were retrospectively reviewed and the most common abnormalities on high resolution computed tomography (CT) of the temporal bone described., Results: Congenital fixation of the stapes footplate was present in nearly all cases of stapedial tendon absence (n = 8, 89%), a clinically important association because the stapes footplate abnormality was not detectable on preoperative CT. Absence or hypoplasia of the pyramidal eminence and aperture was identified in almost all cases (n = 8, 89%), which may be the sole imaging finding to suggest stapedial tendon absence and associated stapes footplate fixation prior to surgery., Conclusion: The most reliable indicator of stapedial muscle absence on temporal bone CT is the absence or hypoplasia of the pyramidal eminence and aperture. Importantly, most patients had congenital stapes footplate fixation confirmed intraoperatively with a normal stapes footplate on CT, meaning the pyramidal eminence/aperture abnormality was the only preoperative imaging finding that could have suggested the footplate fixation., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Purpose: Progressive adherent pars tensa occasionally induces ossicular erosion. Specifically, stapes discontinuity adversely affects postoperative hearing. However, this irretrievable sequela is challenging to prove preoperatively, partly because perimatrix inflammation on the pars tensa can obscure the visibility of the ossicles or the partial volume effect of computed tomography (CT) imaging can hamper detailed ossicular visualization. Therefore, there is no consensus regarding the ideal timing for switching from a wait-and-see approach to a surgical one. Herein, we aimed to explore the potential predictors of stapes superstructure destruction in adherent pars tensa., Methods: This retrospective cohort study enrolled consecutive patients who underwent primary tympanoplasty for adherent pars tensa categorized as grade IV on Sadé's grading scale between April 2016 and September 2021. The impact of features on otoscopy and CT and air-bone gap (ABG) on stapes superstructure destruction was assessed using uni- and multivariable logistic regression analyses., Results: Sixty-four ears were included. Multivariate analysis revealed the presence of debris on the adherent pars tensa (odds ratio [OR] [95% confidence interval {CI}]): 4.799 [1.063-21.668], p = 0.0415), presence of soft-tissue density occupying the oval window (OR [95% CI]: 13.876 [3.084-62.437], p = 0.0006), and a ≥ 20-dB preoperative ABG at 3 kHz (OR [95% CI]: 7.595 [1.596-36.132], p = 0.0108) as independent predictors for stapes superstructure destruction., Conclusion: High preoperative awareness of the possibility of destruction of the stapes superstructure would enable the surgeon to make a timely decision to provide surgical intervention before progression to severe stapes destruction, thereby maintaining long-term satisfactory hearing., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Stapes gusher is a massive flow of perilymph and cerebrospinal fluid leak that fills the middle ear immediately after surgical opening of the labyrinth, such as during stapedectomy. Stapes gusher usually occurs as the result of a congenital malformation that causes an abnormal communication between the perilymphatic space and the subarachnoid space involving the internal auditory canal or the cochlear duct. To date, the potential risk of stapes gusher cannot be assessed preoperatively, as there are not pathognomonic signs suggestive of this complication. However, high-resolution computed tomography scan (HRCT) of the temporal bone can provide information that may help recognizing patients at risk. Recently, an anatomic evaluation of the inner ear with oblique reformation at HRCT has been described. This reformation offers a new and more detailed topographic vision of temporal bone structures compared to the classic axial and coronal planes and may help identifying anatomical alterations otherwise not visible. In this article, we present a case of stapes gusher and the role of preoperative HRCT with oblique reformation in its prevention.

A persistent stapedial artery originates from the petrous segment of the internal carotid artery due to failure of the regression of the embryonic stapedial artery. During embryologic development, the stapedial artery supplies the middle meningeal artery through the ventral pharyngeal artery. The presence of a persistent stapedial artery can result in direct communication between the basilar and middle meningeal arteries. We present a cerebral angiogram image of an adult patient that shows a right-sided persistent stapedial artery with communication between the right middle meningeal and basilar arteries. It is important to recognize such rare anatomic variants during endovascular interventions to avoid catastrophic complications such as nontarget embolization of the posterior circulation., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Purpose: This study aimed to assess stapes visualization using an ultra-high resolution computed tomography (U-HRCT)., Method: Sixty ears from 30 cadaveric human heads were scanned by both U-HRCT and 128-section multislice CT (MSCT) with clinical parameters. Image quality of the stapes head, anterior and posterior crura, footplate, incudostapedial joint and stapedial muscle within the pyramidal eminence was scored using a 3-point Likert scale. Linear measurements of the stapes configuration were performed on U-HRCT., Results: The interobserver agreement for image qualitative score on U-HRCT was good to excellent (interobserver agreement coefficients 0.65-0.86). With the exception of the stapes head, U-HRCT achieved significantly higher qualitative scores than MSCT across all anatomical structures (Ps < 0.05). The total height of the stapes was measured to be 3.48 ± 0.33 mm. The height and width of the obturator foramen were 1.77 ± 0.28 mm and 2.19 ± 0.33 mm, respectively. The widths of the anterior and posterior crura were 0.20 ± 0.06 mm and 0.22 ± 0.06 mm, respectively. The thickness of the footplate was 0.22 ± 0.06 mm, and the angle of the incudostapedial joint was 95.91 ± 10.69°., Conclusions: U-HRCT is capable of delineating fine structures of the stapes and provides linear data on dimensions of the stapes, which could be helpful for detecting stapes disease and making individualized surgical plans in the clinical setting., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objectives: Congenital cholesteatomas originate from epithelial tissue present within the middle ear in patients with an intact tympanic membrane, no history of otologic surgery, otorrhea, or tympanic membrane perforation. They are diagnosed by a pearl-like lesion on otoscopy and computed tomography (CT) scan showing an expansile soft-tissue mass. We describe a series of patients with no prior otologic history presenting with progressive unilateral conductive hearing loss and normal otoscopy. The CT scans showed ossicular erosion without obvious soft-tissue mass. Surgery confirmed incudostapedial erosion found to be cholesteatoma. In this study, we characterize the clinical course of patients diagnosed with isolated incudostapedial cholesteatoma (IIC) and review possible pathologic mechanisms., Methods: Retrospective review of IIC cases treated by the Department of Pediatric Otolaryngology, Rady Children's Hospital, San Diego, 2014 to 2020. Data included patient demographics, clinical features, imaging, surgical findings, and audiologic data., Results: Five patients were diagnosed with IIC (3 [60%] female; mean age at presentation 10.7 years [range 5.5-16.0]). All patients presented with postlingual unilateral conductive hearing loss and normal otoscopy without any past otologic history; delay in diagnosis ranged from 4 months to several years. The CT scans showed ossicular chain erosion with an absent long process of the incus and/or stapes superstructure. All patients underwent middle ear exploration, revealing a thin layer of cholesteatoma in the incudostapedial region, confirmed by histopathology. Mean preoperative speech reception threshold was 55 dB and improved to a mean of 31 dB in the 4 patients who underwent ossicular chain reconstruction., Conclusion: Isolated incudostapedial cholesteatoma should be included as a possible etiology in pediatric patients with insidious onset of unilateral conductive hearing loss with normal otoscopy, unremarkable otologic history, and a CT scan showing ossicular abnormality/disruption without notable middle ear mass. These patients should be counseled preoperatively regarding the possibility of cholesteatoma and should undergo middle ear exploration with possible ossiculoplasty.

Purpose: The aims of the present study were to identify detailed positional relationship between the auditory ossicles and to provide theoretic navigational guidelines for optimal prosthesis adaptation and effective malleostapedotomy., Methods: Fifty sides of the temporal bone from donated cadavers were scanned by MicroCT and the malleus, incus, stapes and tympanic membrane were materialized three dimensionally using computer software. Dimensions between the auditory ossicles closely related to malleostapedotomy were measured twice., Results: The grip site of malleus handle was mean 1.8 mm superior and mean 1.3 mm anterior, and linear distance between the grip site of malleus handle and the footplate of the stapes was mean 6.5 mm. The stapes was not parallel to the tympanic membrane and rotated mean 10.7° posteriorly relative to the tympanic membrane., Conclusion: Surgeons should start with at least 8.75 mm prosthesis to cover the upper limits of potential anatomy and then trim down to the individualization to the case. The ideal loop morphology has to be oval shape more than 1.4 mm in the long diameter and 1.0 mm in the short diameter. The wire of the prosthesis has to be bended at the two points: about 10° anteriorly at the most proximal point of the wire and about 50° superiorly at the stapes head point.

A detailed anatomy of the braincase and stapes of the subadult specimen of Diadectes absitus from early Permian sediments of Germany are described for the first time based on the high-resolution X-ray microcomputed tomography. In contrast to previous studies of Diadectes, the bones of the braincase (opisthotic, prootic, supraoccipital, basioccipital, exoccipital, basisphenoid, and sphenethmoid), and parasphenoid of D. absitus are not co-ossified, but suturally defined. This has allowed for a reconstruction of a complete braincase with all sutures between the individual bones. The opisthotic, prootic, and supraocciptal contain a well-preserved endosseous labyrinth. The three-dimensional-reconstruction of its cavities shows a well-preserved vestibule, three semicircular canals, and well-developed cochlear recess. In addition, a shallow subarcuate fossa is present on the ventral surface of the supraoccipital, which lies medial to the anterior semicircular canal. A typical feature of the diadectid braincase is the presence of the otic tube leading from the fenestra vestibuli to the vestibule. A revision of the topology of this structure is presented here. Here, we describe new structures of the stapes, especially in its proximal portion, as well as its position to the fenestra vestibuli. These structures are described for the first time not only in D. absitus, but for the genus., (© 2020 American Association for Anatomy.)

Background: Ultra-high-resolution computed tomography (U-HRCT) utilizes a 1024 × 1024 matrix with 0.25-mm section thickness, offering better spatial resolution than conventional multi-detector row CT to detect anatomic data for otologic surgery., Aims: We examined stapes footplate thickness using U-HRCT in relation to stapedotomy to predict the difficulty of the surgical procedure., Materials and Methods: Subjects were 12 otosclerosis patients and 25 controls who underwent diagnostic U-HRCT. A profile curve (Hounsfield units) was used to measure stapes footplate thickness along a perpendicular line across the stapes footplate in a plane parallel to the lateral semicircular canal., Results: Footplate thickness was smaller at the midpoint than just before the anterior crus and just after the posterior crus. Interobserver variability was lowest at the midpoint, where foot plate thickness was significantly greater in the affected ear in otosclerosis patients compared with controls (0.60 ± 0.09 mm vs 0.46 ± 0.04 mm; p  < .001). Otosclerosis patients were detected using U-HRCT with a high area under the curve. Difficulty in the stapes opening procedure correlated with stapes footplate thickness., Conclusions: Footplate thickness on U-HRCT correlated with temporal bone anatomy and corresponded to surgical difficulty. Significance: U-HRCT-derived anatomic data is useful for evaluating the stapes.

Treacher Collins syndrome (TCS: OMIM 154500) is an autosomal dominant craniofacial disorder belonging to the heterogeneous group of mandibulofacial dysostoses., Objective: To investigate four Treacher Collins syndrome patients of the Sgaw Karen family living in Thailand., Method: Clinical examination, hearing tests, lateral cephalometric analyses, Computed tomography, whole exome sequencing and Sanger direct sequencing were performed., Results: All of the patients affected with Treacher Collins syndrome carried a novel TCOF1 mutation (c.4138&#95;4142del; p.Lys1380GlufsTer12), but clinically they did not have the typical facial gestalt of Treacher Collins syndrome, which includes downward-slanting palpebral fissures, colobomas of the lower eyelids, absence of eyelashes medial to the colobomas, malformed pinnae, hypoplastic zygomatic bones and mandibular hypoplasia. Lateral cephalometric analyses identified short anterior and posterior cranial bases, and hypoplastic maxilla and mandible. Computed tomography showed fusion of malleus and incus, sclerotic mastoid, hypoplastic middle ear space with a soft tissue remnant, dehiscence of facial nerve and monopodial stapes., Conclusion: Treacher Collins syndrome in Sgaw Karen patients has not been previously documented. This is the first report of monopodial stapes in a TCS patient who had a TCOF1 mutation. The absence of a common facial phenotype and/or the presence of monopodial stapes may be the effects of this novel TCOF1 mutation., (© 2020 John Wiley & Sons Ltd.)

The incudostapedial joint (ISJ) of the middle ear is important for proper transmission of sound energy to the cochlea. Recently, the biomechanics of the ISJ have been investigated using finite-element (FE) modelling, using simplified geometry. The objective of the present study was to investigate the feasibility of synchrotron-radiation phase-contrast imaging (SR-PCI) in visualising the ISJ ultrastructure. Three human cadaveric ISJs were dissected and scanned using SR-PCI at 0.9 µm isotropic voxel size. One of the samples was previously scanned at 9 µm voxel size. The images were visually compared and contrast-to-noise ratios (CNRs) were calculated (of both bone and soft tissues) for quantitative comparisons. The ISJ ultrastructure as well as adjacent bone and soft tissues were clearly visible in images with a 0.9 µm voxel size. The CNRs of the 0.9 µm images were relatively lower than those of the 9 µm scans, while the ratio of bone to soft tissue CNRs were higher, indicating better discernibility of bone from soft tissue in the 0.9 µm scans. This study was the first known attempt to image the ISJ ultrastructure using an SR-PCI scanner at submicron voxel size and results suggest that this method was successful. Future studies are needed to optimise the contrast and test the feasibility of imaging the ISJ in situ. LAY DESCRIPTION: The human middle ear consists of the eardrum, three small bones (the malleus, incus and stapes) and two joints connecting the bones (the incudostapedial joint and the incudomallear joint). The role of the middle ear is to amplify and transfer sound energy to the cochlea, the end organ of hearing. The incudostapedial joint (ISJ) of the middle ear is a synovial joint which is important for proper transmission of sound energy to the cochlea. Similar to other synovial joints it consists of meniscus, fluid and articulating surfaces. Recently, the biomechanics of the ISJ have been investigated using computational models, using grossly simplified geometry. Synchrotron radiation phase contrast imaging (SR-PCI) is a high-resolution imaging technique used to visualise small structures in three dimensions. The objective of the present study was to investigate the feasibility of using SR-PCI in visualising the ISJ ultrastructure. Three human cadaveric ISJs were dissected and scanned using SR-PCI at 0.9 µm isotropic voxel size. One of the samples was previously scanned at 9 µm voxel size. The images were both qualitatively and quantitatively compared. This study was the first known attempt to image the ISJ ultrastructure using an SR-PCI scanner at submicron voxel size and results suggest that this method was successful. Future studies are needed to optimise the contrast and feasibility of imaging the ISJ in situ., (© 2020 The Authors Journal of Microscopy © 2020 Royal Microscopical Society.)

X-linked stapes gusher syndrome is a genetic form of deafness with distinct radiographic features on temporal bone CT. Hypothalamic hamartoma is a congenital glioneuronal anomaly of the hypothalamus. We report a potential association between these two rare anomalies that, to our knowledge, has not been reported. Two brothers presented with sensorineural hearing loss and almost identical inner ear and hypothalamic abnormalities, consistent with a diagnosis of X-linked stapes gusher syndrome and hypothalamic hamartoma. Genetic testing revealed identical mutations in the POU3F4 gene associated with X-linked stapes gusher syndrome. Furthermore, multiple vestibular diverticula were seen in both brothers, which have also not been reported with X-linked stapes gusher syndrome. This case suggests that POU3F4 mediated X-linked stapes gusher syndrome may also lead to multiple vestibular diverticula and hypothalamic hamartoma and, therefore, brain magnetic resonance imaging (MRI) could be considered in patients presenting with these inner ear findings.

In incus stapedotomy surgeries, the longitudinal direction of the piston prosthesis should ideally be perpendicular to the stapes footplate. However, in reality, some amounts of angular deviation of the prosthesis from the ideal angular position is unavoidable due to anatomical constraints and surgical conditions. This study aims to evaluate the influence of angular positioning of the prosthesis on surgical outcomes in incus stapedotomy and to provide surgical guidelines related to practical tolerance of the angular positioning. In this study, this influence was assessed with a Kurz NiTiBond prosthesis (0.4-mm diameter) and fenestra sizes of 0.5- and 0.6-mm diameter in cadaveric temporal bones (n = 7 including 2 preliminary tests). Angular position of the prosthesis relative to the footplate was modulated by rotating the stapes about the long and short axes of the footplate. At each angular position, the tympanic membrane was acoustically stimulated in the frequency range of 0.2-10 kHz, and motion of the prosthesis was measured using a Laser Doppler vibrometer (LDV). Furthermore, micro-computed tomography (micro-CT) data of the middle-ear ossicles were used for anatomical analysis of angular positioning of the prosthesis. The results showed that changes of angular position of the prosthesis relative to the stapes footplate do not cause significant changes of prosthesis motion until a certain angular position threshold, and sharply attenuate prosthesis motion when the angular position reaches the threshold. The threshold of the angular position, as the tilting angle of the prosthesis from the direction normal to the stapes footplate, was 26.9 ± 2.5° with the fenestration hole of 0.5-mm diameter and 30.6 ± 3.0° with the fenestration hole of 0.6-mm diameter (n = 5, p < 0.01 for difference between the two fenestra sizes). Analysis of the middle-ear anatomy in this study revealed that the tolerances of the angular positions of the prosthesis does not always cover possible positions of prosthesis crimping. This study suggests that if an anterior offset of the stapes head and/or the thickened footplate is suspected, efforts to locate prosthesis crimping closer to the tip of the incus and/or to make a sufficiently large fenestration hole are favorable., (Copyright © 2019 Elsevier B.V. All rights reserved.)

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.

Objective: The aim of this study is to understand the imaging morphology of the humerus morphology and its associated simulated lesions, and to provide information for related research. Method: Six adult cadaveric heads fixed by formaldehyde solution (12 sides of the tibia) were used. One of the cadaveric heads (two sides of the tibia) was perforated and fractured under the microscope.The remaining 5 (10 sides) were used. The humerus was used for morphological measurements of the tibia.The tibia (12 sides) was taken out, Micro-CT scan was performed, and two-dimensional and three-dimensional reconstruction were performed using software such as Mimics 17.0 software. Result: ①Stapedial morphologic observation:the head,curs and footplate of the stapes and the adjacent structures can be well displayed on two dimensional structures.②Quantitative measurements and statistics: There were no significant statistic differences about the data that had been measured between the right ears and the left ears.③Micro-CT was more clearly in displaying the precise structure of human stapes and the stapedial minute lesion comparing with that of HRCT. Conclusion: Micro-CT can accurately and clearly display the structure, morphology and simulated lesions (model) of the tibia, which provides important reference materials and methods for related research., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)

Background: The annular ligament of the human stapes constitutes a compliant connection between the stapes footplate and the peripheral cochlear wall at the oval window. The cross section of the human annular ligament is characterized by a three-layered structure, which resembles a sandwich-shaped composite structure. As accurate and precise descriptions of the middle-ear behavior are constrained by lack of information on the complex geometry of the annular ligament, this study aims to obtain comprehensive geometrical data of the annular ligament via multiphoton imaging., Methods: The region of interest containing the stapes and annular ligament was harvested from a fresh-frozen human temporal bone of a 46-years old female. Multiphoton imaging of the unstained sample was performed by detecting the second-harmonic generation of collagen and the autofluorescence of elastin, which are constituents of the annular ligament. The multiphoton scans were conducted on the middle-ear side and cochlear side of the annular ligament to obtain accurate images of the face layers on both sides. The face layers of the annular ligament were manually segmented on both multiphoton scans, and then registered to high-resolution μCT images., Results: Multiphoton scans of the annular ligament revealed 1) relatively large thickness of the core layer compared to the face layers, 2) asymmetric geometry of the face layers between the middle-ear side and cochlear side, and variation of their thickness and width along the footplate boundary, 3) divergent relative alignment of the two face layers, and 4) different fiber composition of the face layers along the boundary with a collagen-reinforcement near the anterior pole on the middle-ear side., Conclusion and Outlook: Multiphoton microscopy is a feasible approach to obtain the detailed three-dimensional features of the human stapedial annular ligament along its full boundary. The detailed description of the sandwich-shaped structures of the annular ligament is expected to contribute to modeling of the human middle ear for precise simulation of middle-ear behavior. Further, established methodology in this study may be applicable to imaging of other middle-ear structures., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Tarsal-carpal coalition syndrome is a progressive condition involving synostosis of the wrist, ankle and digits. We describe a mother and her newborn that have this rare inherited condition where the diagnosis was made only after the baby's birth. The baby's condition was suspected on antenatal scanning, and he was born with reduced range of motion of his digits, elbows and ankles. The mother's condition has progressed to involve a fixed flexion deformity of her bilateral elbows, synostoses of her second to fifth digits and extensive coalition of her tarsal and carpal bones. She has required regular osteotomies to improve limb functioning and quality of life., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

We report 2 cases of stapes surgery failure due to the depth marker groove of the piston of a Big Easy titanium prosthesis getting caught at the edge of the stapedotomy hole. In the first case, the stapedotomy failure, detected peroperatively, was corrected by modifying the angulation of the shaft of the prosthesis. In the second case, the failure occurred after a delay during which scar tissue developed around the depth marker groove, hampering the movement of the prosthesis. The usual postoperative imaging did not detect this complication. The diagnosis was made during revision surgery and the condition was treated by enlarging the hole in the footplate. Alternatively, the use of a piston without a depth marker groove would have resolved the problem. Although a rare event, the possibility of stapes surgery failure due to the depth marker groove should not be overlooked.

Background: The anatomy of the membranous labyrinth within the vestibule has direct implications for surgical intervention. The anatomy of the otoliths has been studied, but there is limited information regarding their supporting connective tissue structures such as the membrana limitans in humans., Methods: One guinea pig and 17 cadaveric human temporal bones were scanned using micro computed tomography, after staining with 2 per cent osmium tetroxide and preservation with Karnovsky's solution, with a resolution from 1 µm to 55 µm. The data were analysed using VGStudio Max software, rendered in three-dimensions and published in augmented reality., Results: In 50 per cent of ears, the membrana limitans attached directly to the postero-superior part of the stapes footplate. If attachments were present in one ear, they were present bilaterally in 100 per cent of cases., Conclusion: Micro computed tomography imaging allowed three-dimensional assessment of the inner ear. Such assessments are important as they influence the surgical intervention and the evolution of future innovations.

Background: The insertion of the stapes piston into the vestibule provides the physical basis for a successful stapedotomy. In routine clinical practice, two different ways to handle prosthesis length are performed: (1) an individualized measurement of the stapes prosthesis length or (2) a standard prosthesis length for all cases., Objective: The objective of this study was to compare both ways of handling prosthesis length and the effect of these methods on insertional prosthesis depth., Material and Method: We retrospectively evaluated 39 patients after performing a stapedotomy for radiologically estimated vestibular stapes prosthesis insertion depth. The individual measured length data were hypothetically changed to a standard length of 4.75, 5, 5.25, and 5.5 mm, and the insertion depths were compared., Results: The individually measured prosthesis lengths led to an insertion depth between 0.2 and 1.6 mm (mean 0.74 mm). The ratio of insertion depth/vestibular depth was between 8 and 59.1% (mean 26.6%). The different assumed standard lengths led to different rates of the vestibulum positions and possible bony contacts at the vestibulum floor., Conclusion: The individual measurement led to a zero rate of the vestibulum positions of stapes prosthesis pistons with a low insertion depth/vestibular depth ratio., (© 2019 S. Karger AG, Basel.)

Introduction: The aim of this work was to report and describe the different types of congenital middle ear malformations in order to guide surgical treatment approaches and improve outcomes for affected patients., Methods: The authors reviewed patients with congenital middle ear malformations who received surgical treatment between September 2010 and March 2017. Patient characteristics, middle ear deformities, and surgical procedures were documented., Results: In this retrospective study, 35 patients were reviewed. A description of middle ear malformation was proposed that considers ear embryogenesis and focuses on stapes deformity, with the main purpose of facilitating surgical approach selection to reconstruct the ossicular chain. Patients were classified into 3 categories: type I (19 cases), mobile stapes footplate, which included type Ia with normal stapes suprastructure and type Ib with abnormal stapes suprastructure; type II (4 cases), fixed stapes footplate, which included type IIa with normal ossicular chain and type IIb with abnormal ossicular chain; and type III (12 cases), oval window bony atresia or aplasia, with or without round window atresia. Types II and III could have concomitant aberrant facial nerve. Different surgical approaches are described., Conclusions: The authors describe the different types of congenital middle ear malformations. This category description considers ear embryogenesis and is focused on stapes deformity. It may provide better understanding of disease development and guide modern hearing reconstructive surgery.

Objective: (1) To assess the correlation between preoperative high-resolution CT (HRCT) imaging measurement from the long process of the incus to the footplate and the length of intraoperative selected prosthesis. (2) To determine if HRCT has a predictive value of prolapsed facial nerve during stapedotomy., Materials and Methods: We evaluated in our tertiary care center, in a retrospective case series, 94 patients undergoing primary stapedotomy. Preoperative temporal bone HRCT scans were reformatted in the plane of the stapes to measure on the same section the distance between the long process of the incus and the footplate. Measurement was performed by otolaryngology resident and neurotologist. We analyze the interobserver correlation and the mean length measured on the HRCT to the selected prosthesis size intraoperatively., Results: Mean HRCT measurement of the incus long process/footplate distance assessed by the otolaryngology resident and neurotologist was 4.34 and 4.38 mm, respectively. Interobserver correlation was statistically significant [intraclass correlation coefficient (ICC) of 0.679 (p < 0.001)]. Mean selected prosthesis length intraoperatively was 4.36 mm. Correlation between the mean selected length prosthesis and the mean HRCT measurement was also statistically significant [ICC of 0.791 (p < 0.001)]. Postoperatively, a statistical improvement was shown in air conduction (p < 0.001), bone conduction (p < 0.001) and air-bone gap reduction (p < 0.001). 2 cases of facial nerve covering one-half of the oval window were identified by HRCT and confirmed intraoperatively., Conclusion: HRCT is a valuable tool to predict preoperatively the length of the stapedotomy prosthesis. Moreover, it might be helpful to identify a potential prolapsed facial nerve, to confirm the diagnosis of otosclerosis and to rule out other abnormalities. Ultimately, it may optimize the stapedotomy procedure planning.

Although human stapes are known to have varied dimensions and the footplate is considered to be oval (fitting as it does into the oval window), few studies of high-resolution imaging of these structures have been performed. No study appears to have addressed the bilateral symmetry of stapes dimensions or to have determined if an association exists between the size of the stapes and the size of mastoid pneumatization; a small mastoid pneumatization is an indicator of childhood otitis media. We obtained 41 ear-normal cadaver crania specimens for study in our temporal bone laboratory and isolated 10 for further analysis: the 5 with the largest areas of mastoid pneumatization and the 5 with the smallest. Microcomputed tomography of tissue blocks was performed on the in situ stapes. Using ImageJ software, we created a three-dimensional model of each stapes. The mean height of these stapes was 3.43 mm (range: 3.20 to 3.80), the mean length of the footplates was 2.71 mm (range: 2.52 to 2.97), and the mean width of the footplates was 1.23 mm (range: 1.12 to 1.46). Qualitatively, the footplate was shaped like a human footprint in moist sand, as Eysell described in 1870. The dimensions of the stapes were found to be bilaterally symmetrical in general, but there was no correlation between these dimensions and the size of mastoid pneumatization. The distribution of footplate widths may be bimodal, which is consistent with the observation of Sim et al that men have wider footplates than do women.

The objective of the present study was to characterize the effectiveness of the audiological and radiological diagnostic techniques as well as the results of the surgical treatment of the patients presenting with otosclerosis based at the hospital clinic of the Pacific State Medical University. The analysis included 49 surgical interventions for stapedoplasty carried out on 42 patients during the period from 2015 to 2017. The tympanic form of the disorder was diagnosed in 51.02% of the cases, the mixed form I in 16.28%, and the mixed form II in 32.7%. The excellent results within two months after surgery were obtained in 87.2% of the treated patients, the good and satisfactory results in 8.72% and 4.08% of them respectively.

Introduction: Temporal bone fractures are frequently associated with ossicular dislocations or fractures, most commonly involving the incus. To our knowledge, isolated fracture of the posterior crus of the stapes has not been previously reported., Case Report: A 20-year-old man consulted for persistent left hypoacusis several months after a head injury. Initial computed tomography of the temporal bone showed a simple temporal bone fracture with no other associated abnormalities. The diagnosis of stapes fracture was suggested by increased compliance on tympanometry, leading to a second thin-section temporal bone computed tomography, which suggested a fracture of the posterior crus of the stapes. Endaural surgical exploration confirmed the diagnosis and allowed placement of ionomer cement in the posterior crus., Discussion: The possibility of ossicular dislocation or fracture must be considered in patients with persistent conductive hearing loss associated with increased compliance on tympanometry, even when computed tomography of the temporal bone does not show dislocation of the ossicular chain or ossicular fracture. Hearing rehabilitation can be performed by hearing aid or surgical reconstruction of the ossicles., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

The oval window region has recently been identified as a potential route for drug diffusion into the inner ear. Locally applied gadolinium and trimethylphenylammonium (TMPA) have been shown to directly diffuse into the vestibule through the oval window region. Given the potential importance of the oval window region in the diffusion of substances into the inner ear, this work aimed to use micro-CT to obtain a data set of anatomical characteristics of the annular ligament of the stapes in the human temporal bone, a region thus far poorly studied. Twenty-one temporal bones were micro-dissected to preserve the otic capsule and allow perfusion of fixative stains into the inner ear. The specimens were scanned with micro-CT methods to provide 3D reconstructions and measurement. The 3D reconstructions were able to demonstrate an undisturbed stapes footplate and annular ligament from which measurements could be taken. This study found a wide variance in the volumes and thicknesses of the stapedial ligaments. There was a positive correlation between the size of the stapes footplate and the annular ligament.

Objective: To assess the diagnostic efficacy and therapeutic impact of CT in evaluating patients with clinically suspected otosclerosis., Methods: CT scans performed over a 5-year period for clinically suspected otosclerosis were retrospectively reviewed. CT diagnoses were correlated with subsequent surgical management. For otosclerosis positive cases, clinically significant extensions of otosclerosis were correlated with audiometry and the diagnosis was correlated with surgical findings., Results: Of 259 CT studies, 46 % of patients were positive, 49 % negative and 5 % equivocal for otosclerosis. A relevant alternative CT diagnosis was evident in 33 % of the negative studies. One targeted surgery was performed for every four CT studies. CT outcome influenced the decision to perform stapedectomy in 41 % CT-positive versus 4 % CT-negative patients. CT-positive ears for otosclerosis could not be predicted from baseline clinical or audiometric criteria. Those with endosteal extension demonstrated lower bone conduction thresholds presurgically. The positive predictive value of CT diagnosis of otosclerosis was 100 %., Conclusions: CT demonstrated a high rate of clinically relevant diagnoses in both CT-positive and -negative for otosclerosis patients, and this frequently influenced surgical management. CT also added value by demonstrating relevant extensions of the otosclerotic foci, some of which were predictive of audiometric parameters., Key Points: • CT demonstrates a high rate of alternative diagnoses in suspected otosclerosis, 1:3. • CT results in a high rate of targeted surgery in suspected otosclerosis, 1:4. • CT prevents exploratory surgery in suspected otosclerosis. • Endosteal extension of otosclerosis is predictive of lower bone conduction tresholds presurgically. • The PPV of CT diagnosis of otosclerosis was 100 %.

Background: The 6p25 deletion syndrome is one of the many syndromes with both hearing impairment as well as vision impairment. However, the audiometric characteristics and radiological findings of patients with 6p25 deletions are only scarcely described in literature. This study focused on characterizing the audiometric and radiological features of a Belgian family with a chromosome 6p25 deletion., Objective: To evaluate the hearing impairment, audiometric testing and radiological examination of the temporal bones in 3 family members with a 3.4 Mb deletion in chromosome band 6p25., Results: All 3 family members demonstrated slowly progressive sensorineural or mixed hearing impairment. Radiologic examination revealed thickened and sclerotic stapes in all patients and a minor internal partition type II of the cochlea in 2 patients., Conclusion: There is a significant phenotypic variability within and among families with the 6p25 deletion syndrome. A thorough genotype-phenotype correlation is difficult because of the small number of affected patients and the limited clinical data available. More clinical data of families with 6p25 deletions need to be published in order to create a reliable and precise phenotypic characterization. However, our findings can facilitate counseling of hearing impairment caused by 6p25 deletions., (© The Author(s) 2016.)

Objectives: The aims of this article are: 1) to re-evaluate the accuracy of multiple planar reconstruction computed tomography (MPR-CT) imaging on stapes-prosthesis parameters, and 2) to clarify possible relationships between prosthesis intravestibular depth and postoperative hearing outcomes., Patients: Seventy patients (46 women and 24 men; 32 right and 38 left sides) with the mean age of 40 years (range, 19-62 yr) with clinical otosclerosis., Intervention(s): All patients underwent stapedotomy and were implanted with the same type of titanium piston prosthesis by the same surgeon., Main Outcome Measure(s): Postoperative MPR-CTs were obtained at patients' follow-up visits. The length and intravestibular depth of the stapes prosthesis (including absolute and relative depth) were calculated from the MPR-CT imaging. Relationships between the intravestibular depth of the prosthesis and hearing outcomes (pre- and postoperative audiograms) were analyzed using Spearman correlation analyses., Results: The length of the prosthesis was overestimated by 1.8% (0.1 mm) by the MPR-CT imaging. Axial and coronal measurements were significantly correlated (p < 0.05). There was great intersubject variability in hearing outcomes differed insignificantly, regardless of intravestibular depth within the security range. No relationships were found between the intravestibular depth of the stapes prosthesis, as measured with MPR-CT, and postoperative hearing results., Conclusions: MPR-CT can provide an accurate estimation of stapes prosthesis parameters. However, the prosthesis intravestibular depth did not seem to affect postoperative hearing outcomes.

This prospective case review was performed with the aim to compare and asses the diagnostic values of cone-beam computed tomography (CBCT) and high-resolution computed tomography (HRCT) in the preoperative evaluation of otosclerosis. A total of 43 patients with histologically confirmed stapedial otosclerosis, who underwent unilateral stapedectomies were analyzed. Preoperative temporal bone CBCT and HRCT scans were performed in all cases. Both CBCT and HRCT imaging were characterized by a slice thickness of 0.4-0.625 mm and multiplanar image reconstruction. Histopathologic examination of the removed stapes footplates was performed in all cases. Findings of CBCT and HRCT were categorized according to the modified Marshall's grading system (fenestral or retrofenestral lesions). Histopathologic results were correlated with multiplanar reconstructed CBCT and HRCT scans, respectively. Negative control groups for CBCT (n = 36) and HRCT (n = 27) examinations consisted of patients, who underwent CBCT imaging due to various dental disorders or HRCT analysis due to idiopathic sudden sensorineural hearing loss. Histologically active foci of otosclerosis (n = 31, 72 %) were identified by both CBCT and HRCT in all cases with a sensitivity of 100 %. However, CBCT could not detect histologically inactive otosclerosis (n = 12, 23 %; sensitivity 0 %). In contrast, HRCT showed inactive otosclerosis with a sensitivity of 59.3 %. According to CBCT results, no retrofenestral lesions were found and the overall sensitivity for hypodense lesions was 61.37 %. In conclusion, CBCT is a robust imaging method in the detection of histologically active fenestral hypodense foci of otosclerosis with high sensitivity and radiologic specificity. In the light of these results, HRCT still remains the basic imaging method in the preoperative diagnosis of otosclerosis, since it has much greater sensitivity and specificity in the detection of retrofenestral hypodense lesions and histologically inactive otosclerotic foci in the oval window niche.

Objective: To describe congenital anomalies of the incudostapedial joint (ISJ) and to discuss the possible unique embryogenesis of the ISJ based on the two anomalies that were encountered., Setting: Tertiary care medical center., Subjects and Methods: Retrospective review of the medical records of all patients with ISJ anomalies., Results: Four patients presented with congenital hearing loss. Upon further workup, we observed a preserved incudostapedial joint (ISJ) with deficiencies of the incus and stapes in three cases. Our fourth case demonstrated the inverse pattern of the congenital anomalies in which the ISJ was missing with an intact proximal incus and stapes crura. Three patients opted for surgical intervention with improvement in hearing. One case preferred hearing amplification over surgery., Conclusion: Isolated ISJ malformations are uncommon potential causes of congenital conductive hearing loss. Although numerous patterns of ossicular anomalies have been reported in the literature, our case series is the first to demonstrate both the absence of the ISJ in one patient and the presence of the ISJ in the presence of missing stapes crura and incus body in other patients. Though limited by the small number of cases, the inverse relationship of the single case compared to the three other cases, suggests a possible independent embryological development pathway for the ISJ. Therefore, an embryological explanation of the defects should be considered. Additionally, surgical intervention can improve hearing outcomes for patients with isolated ISJ anomalies., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Hypothesis: Determining the spatial distribution of the malleus handle in relationship to the stapes as a function of the condition of the ossicular chain., Background: The position of replacement prosthesis and by association the direction of the force vectors exerted on the stapes head or footplate depends on the location of the malleus handle in relationship to the stapes and the contact point of the prosthesis at the malleus. Ideally, the force of prosthesis is conducted along an imaginary line through the center of the footplate and the stapes head., Methods: Fifteen cadaveric human temporal bone specimens were investigated by means of micro-CT followed by 3D analysis. For different contact points, the angulation of a virtual rod prosthesis compared with the ideal reconstructive situation was determined., Results: In case of missing incus, angulation of an imaginary line from stapes head to the most medially located point of the malleus handle (on average, 0.6 mm above the malleus tip) averages 85 ± 8 degrees (95% CI, 80-89 degrees) and to the upper end of the malleus handle 69 ± 7 degrees (95% CI, 65-73 degrees). Angulation from the center of the footplate to the malleus tip averages 37 ± 7 degrees (95% CI, 33-41 degrees) and to the upper end of the malleus 33 ± 5 degrees (95% CI, 30-36 degrees). The differences of the spatial distribution of the malleus handle in relationship to the stapes in different conditions of the ossicular chain are not relevant., Conclusion: In contrast to the ideal reconstructive situation, the present data show a malleus-stapes offset with particular unfavorable angles for a stapes head to malleus tip assembly.

Multiple synostosis syndrome (SYNS) is an autosomal dominant skeletal disorder characterized by facial dysmorphism, progressive fusion of multiple joints, and conductive hearing loss. Currently, three genes, NOG, GDF5, and FGF9, have been identified as causative of SYNS. However, due to the phenotypic and genotypic heterogeneity of SYNS, as well as its extreme rarity, it is difficult to diagnose, either by clinical or genetic means. Here, we describe three unrelated Korean families with three different, novel NOG mutations. These mutations are located on the region of the protein critical for appropriate NOG function. The patients shared the general features of SYNS, but the phenotype was expressed differently both within and between the families. In addition, this phenotypic diversity was irrespective of the age of patients, indicating the importance of surveillance for the full spectrum of SYNS in each affected patient. Our report expands understanding of this rare condition from both clinical and genetic perspectives., (Copyright © 2014 Société française de rhumatologie. Published by Elsevier SAS. All rights reserved.)

Objective: The stapes is difficult to analyse on computed tomography because of the small size of its components and its oblique orientation. The stapes axial plane, parallel to the superstructure, seems optimal for this purpose. The present study assessed the position of the stapes axial plane with respect to the usual axial plane including the lateral semicircular canal, and sought to measure the main dimensions of the stapes., Methods: This retrospective study comprised 208 computed tomography scans of normal ears. Stapes length and width, footplate thickness and incudostapedial joint width were measured., Results: The stapes axial plane was directed upward, outward (44°) and forward (12°) with respect to the lateral semicircular canal plane. Mean head-to-footplate distance was 3.7 mm and mean superstructure width was 2.7 mm. Mean footplate thickness was 0.27 mm on stapes axial plane versus 0.48 mm on lateral semicircular canal plane. Incudostapedial joint width was systematically less than 0.7 mm., Conclusion: Stapes dimensions on stapes axial plane were close to anatomical data, particularly for footplate thickness.

Understanding of the embryologic origin of the stapes remains controversial. Theories diverge upon whether the entirety of the stapes arises from a single source versus the footplate and suprastructure arising from distinct sources. A 12-year-old boy with left-sided conductive hearing loss had computed tomography of the temporal bone, revealing an inferiorly displaced left stapes, and a nonspecific density in the left Prussak's space. Exploratory tympanotomy revealed the crura of the stapes to be attached to the promontory. The stapes footplate was located in the oval window and was mobile., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Objective: Pneumolabyrinth resulting from temporal bone trauma and stapes luxation has been associated with sensorineural hearing loss (SNHL). The principal purpose of this study was to determine the incidence and volume of pneumolabyrinth after stapedotomy in which iatrogenic perilymphatic fistula is created and to also correlate this with possible hearing loss and vertigo., Study Design: Prospective study., Setting: Tertiary referral center., Patients and Methods: Fifty stapedotomy patients were operated on for otosclerosis, and of those 50, 20 underwent high-resolution computed tomography (CT) on the first day, 10 on the third day, and 20 on the seventh day. The patients followed up regarding SNHL and vertigo that could develop postoperatively, and the correlation of such complications with HRCT findings was examined., Results: The 20 patients who had high-resolution CT (HRCT) on the first day all presented with pneumolabyrinth, and none of the 20 patients who underwent HRCT on the seventh day had pneumolabyrinth. Postoperatively, 92% of the patients had less than 20 dB and 62% had less than 10 dB air-bone gap. None of the patients had SNHL or persistent vertigo. There was no correlation between pneumolabyrinth and hearing loss or vertigo., Conclusion: Pneumolabyrinth is a radiological sign of perilymphatic fistula and has no effect on sensorineural hearing loss and vertigo. Observing pneumolabyrinth during the early postoperative stage should not necessarily implicate a complication; however, pneumolabyrinth after the first week supported with the clinical symptoms of perilymphatic fistula would be a meaningful finding.