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Purpose: Patient-to-image registration is a preliminary step required in surgical navigation based on preoperative images. Human intervention and fiducial markers hamper this task as they are time-consuming and introduce potential errors. We aimed to develop a fully automatic 2D registration system for augmented reality in ear surgery., Methods: CT-scans and corresponding oto-endoscopic videos were collected from 41 patients (58 ears) undergoing ear examination (vestibular schwannoma before surgery, profound hearing loss requiring cochlear implant, suspicion of perilymphatic fistula, contralateral ears in cases of unilateral chronic otitis media). Two to four images were selected from each case. For the training phase, data from patients (75% of the dataset) and 11 cadaveric specimens were used. Tympanic membranes and malleus handles were contoured on both video images and CT-scans by expert surgeons. The algorithm used a U-Net network for detecting the contours of the tympanic membrane and the malleus on both preoperative CT-scans and endoscopic video frames. Then, contours were processed and registered through an iterative closest point algorithm. Validation was performed on 4 cases and testing on 6 cases. Registration error was measured by overlaying both images and measuring the average and Hausdorff distances., Results: The proposed registration method yielded a precision compatible with ear surgery with a 2D mean overlay error of 0.65 ± 0.60 mm for the incus and 0.48 ± 0.32 mm for the round window. The average Hausdorff distance for these 2 targets was 0.98 ± 0.60 mm and 0.78 ± 0.34 mm respectively. An outlier case with higher errors (2.3 mm and 1.5 mm average Hausdorff distance for incus and round window respectively) was observed in relation to a high discrepancy between the projection angle of the reconstructed CT-scan and the video image. The maximum duration for the overall process was 18 s., Conclusions: A fully automatic 2D registration method based on a convolutional neural network and applied to ear surgery was developed. The method did not rely on any external fiducial markers nor human intervention for landmark recognition. The method was fast and its precision was compatible with ear surgery., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The aim of this research was to assess possible relationships between petrotympanic fissure (PTF) characteristics, malleus position, and temporomandibular joint disorders (TMD). A retrospective study was performed, including patients with TMD. Magnetic resonance imaging (MRI) and cone-beam computed tomography (CBCT) examination were used to evaluate temporomandibular joint (TMJ) disc position and condylar bone changes. Fifty-eight TMJs from twenty-nine patients (23:6 females: males) were assessed. Erosive changes (DDR-disc displacement with a reduction of 6 (24%), DDwR-disc displacement without a reduction of 8 (61.5%) vs. normal disc position 3 (15%), p = 0.012) and condyle osteophytes production (DDR 6 (24%), DDwR 9 (69.2%) vs. normal condyle 7 (35%), p = 0.012) were more frequent in subjects with disc displacement compared to normal disc position; malleus was closer to PTF in cases with erosive changes (median 2.15 interquartile range: (1.85-2.75) vs. 2.75 (2.25-3.15), p = 0.029) as well as those with condylar osteophytosis (2.25 (1.91-2.75) vs. 2.75 (2.33-3.32), p = 0.015); the PTF length was higher in cases with condylar osteophytosis compared to those without (4.45 (3.50-4.77) vs. 3.67 (3.34-4.28), p = 0.039). The disc position and disc shape were not related to PTF or malleus position. Malleus position and PTF dimensions were not associated with the PTF type. In cases with erosive changes and condylar osteophytosis, malleus was closer to PTF.

Objective: To evaluate the application of 10 μm otology CT on evaluation of isolated malleus fixation (IMF) in patients with conductive hearing loss. Methods: A total of 19 patients (25 sides) with idiopathic hearing loss, including 8 males and 11 females, aged between 4 to 50 years, who underwent 10 μm otology CT examination in Department of Radiology, Beijing Friendship Hospital, Capital Medical University from October 2020 to July 2021, were retrospectively collected. For those patients with idiopathic hearing loss, there were 5 cases (6 sides), including 2 males and 3 females, with an average age of 18-70 [65(20,68)] years, with bony connection between malleus and tympanum wall. Eighteen sex-and age-matched cases with normal hearing group, including 6 males and 12 females, with an average age of 20-68 (39±14) years, as the ratio of 1∶3, were included as the controls. The distances of the tegmen tympani between malleus head and horizontal semicircular canal, as well the distances between malleus head and horizontal semicircular canal were retrospectively measured and further compared between the two groups. Results: The incidence of IMF in patients with idiopathic conductive hearing loss without other etiologies was 24.0% (6/25). The specificity of 10 μm otology CT in diagnosing IMF was 100%. The distances of tegmen tympani between horizontal semicircular canal and malleus head in IMF patients were significantly smaller compared with the controls [-0.65(-1.21, -0.35) mm vs 1.34(0.04, 1.68) mm;0.92(0.51, 1.49) mm vs 2.82(1.76, 3.53) mm](both P <0.05, respectively). There was no significant difference in distances between malleus head and horizontal semicircular canal [-1.30 (-1.90, -0.46)mm vs -0.42 (-1.15, 0.05), P =0.057]. Conclusions: IMF is not uncommon in conductive hearing loss without other causes, which can be clearly shown by 10 μm otology CT. Its occurrence is related to the local downward shift of tegmen tympani above the malleus, without upwards displacement of the malleus.

Objective: Report a series of cases in which patients have concomitant superior semicircular canal dehiscence (SSCD) and a dehiscent tegmen tympani with Dural contact to the malleus head (DCMH)., Methods: An analysis of radiologic and audiologic data in 4 patients who presented with SSCD and DCMH at a tertiary care institution. A pertinent literature review was performed., Results: Four patients (5 ears) had SSCD and DCMH. In 3 patients with unilateral DCMH, the mean maximum air-bone gap was 15 dB in the ear with DCMH compared to 50 dB in the ear without DCMH. Of the 5 ears with DCMH, the mean air conduction threshold at 250 Hz was 17 dB compared to 42 dB in the 3 ears without DCMH., Conclusions: We report the findings of DCMH in a series of 4 patients with bilateral SSCD. This limited series suggests that ears with SSCD and DCMH have less of an air-bone gap than would be expected, as 1 would expect an additive effect of DCMH and SSCD on the air-bone gap.

Fibrous dysplasia is an unusual pathologic condition caused by abnormal bone metabolism. Temporal bone involvement is often seen, but it is uncommon to find fibrous dysplasia limited to the middle ear, especially originating in and confined to a single ossicle. Here we report a case of osteofibrous dysplasia limited exclusively to an ossicle (malleus) causing gradual conductive hearing loss, which recovered after eventual complete removal of the dysplastic area. The lesion showed firm attachment to adjacent structures and initial removal was not possible. This report provides information to help other otologic surgeons facing similar conditions., Competing Interests: Declaration of Competing Interest All authors have no conflict of interest., (Copyright © 2020. Published by Elsevier B.V.)

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.

Multispectral imaging has recently shown good performance in determining information about physiology, morphology, and composition of tissue. In the endoscopy field, many researches have shown the ability to apply multispectral or narrow-band images in surveying vascular structure based on the interaction of light wavelength with tissue composition. However, there has been no mention to assess the contrast between other components in the middle ear such as the tympanic membrane, malleus, and the surrounding area. Using CT, OCT, or ODT can clearly describe the tympanic membrane structure; nevertheless, these approaches are expensive, more complex, and time-consuming and are not suitable for most common middle ear diagnoses. Here, we show the potential of using the multispectral imaging technique to enhance the contrast of the tympanic membrane compared to the surrounding tissue. The optical absorption and scattering of biological tissues constituents are not the same at different wavelengths. In this pilot study, multiwavelength images of the tympanic membrane were captured by using the otoscope with LED light source at three distinct spectral regions: 450 nm, 530 nm, and 630 nm. Subsequently, analyses of the intensity images as well as the histogram of these images point out that the 630 nm illumination image features an evident contrast in the intensity of the tympanic membrane and malleus compared to the surrounding area. Analysis of such images could facilitate the boundary determination and segmentation of the tympanic membrane (TM) with high precision., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2020 Tien Tran Van et al.)

Background: Several anatomic relationships between the ear and the temporo-mandibular joint have been proposed to account for the presence of tinnitus during temporo-mandibular disorders. Among the otomandibular structures, the discomallear ligament (DML) is interposed between the malleus and the retrodiscal capsular complex. The aim of present paper was to study through dissection the frequency and morphology of DML, to characterize its type of collagen, and to evaluate the DML on routine computed tomography (CT)., Methods and Results: The study has been conducted on five un-embalmed adult cadavers, and in all cases, the DML was present (100%). It was constituted mainly by fibers of collagen I, with abundant elastic fibers. On CT exams of 40 patients with no reported pathology of the ear, on axial images, a dense structure, going from the upper end of the petrotympanic fissure to the neck of the malleus, was present in all the cases. In 90%, it showed a triangular shape, in 5% a rectangular shape, and in 5% a curved course. The mean length of the antero-medial side was 2 ± 0.6 mm and that of the antero-lateral side was 1.63 ± 0.5, and the mean area was 1.29 ± 0.83 mm 2 ., Conclusion: The DML could represent an anatomical structure that joining the temporo-mandibular joint and the malleus may play a role in the otologic symptoms during temporo-mandibular disorders.

Objectives: The goal of this review was to review our series of isolated malleus fixation in pediatric patients, a rare entity causing conductive hearing loss. Malleolar fixation is poorly described in this patient population., Methods: A retrospective review of pediatric tympanoplasties by the senior author over a four-year period was performed. Only cases with isolated fixation of the malleus were reviewed. Primary outcome of interest was post-operative hearing. Paired t-tests were used to calculate pre- and post-operative hearing outcomes., Results: Five cases were analyzed. Mean age at time of surgery was 9.1 years (range 4.4-16.0 years). Average follow-up after surgery was 13.9 months (range 4.4-31.2 months). Patients were otherwise healthy and typically presented after a failed school hearing test despite previously good hearing. Three out of five cases showed radiographic evidence of bony fixation (60%) on computerized tomography (CT). Otoscopy was unremarkable in all cases. Average procedure time was 41.2 min and consisted of transcanal tympanoplasty with excision of fixed bony segment. A significant improvement in both pre- and post-operative air bone gaps was observed (p = 0.005)., with average ABG of 14.75 dB., Conclusions: Isolated pediatric malleolar fixation is an uncommon cause of pediatric conductive hearing loss. CT scan is useful for identifying this abnormality, and surgical correction results in improved post-operative hearing outcomes, potentially obviating the need for hearing amplification., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: To determine the feasibility of using temporal bone computed tomography (CT) scans to identify malleal ligaments and the prevalence of calcification in malleal ligaments., Study Design: Retrospective case review. CT scans were blindly and retrospectively reviewed by two physicians (a radiologist and a nonradiologist). Scans differed by slice thickness, and included both conventional CT and cone beam CT (CBCT)., Setting: Ambulatory tertiary referral center., Patients: One hundred fifty-one temporal bone CT scans, obtained between the years 2014 and 2017, were initially screened, which included 302 ears. Patients with previous tympanomastoid surgery or middle ear opacification were excluded, leaving 187 ears in the study., Intervention: Diagnostic., Main Outcome Measure: Percentage of visible normal and calcified malleal ligaments., Results: Scans with submillimeter slice thickness were more likely to demonstrate all three malleal ligaments than those with 1 ml and larger slices (83.7% versus 50.0% for nonradiologist, p < 0.0001; 59.6 versus 34.8% for radiologist, p < 0.0001). Calcification was seen in 11.8% of ears reviewed. The ability to detect malleal ligaments with cone beam CT was 86.2%, while the rate with conventional CT was 71.1%, a difference that persisted when controlling for slice thickness. Interobserver agreement for the detection of malleal ligaments was 65% with a Cohen's kappa coefficient of κ = 0.27., Conclusion: Visualization of the malleal ligaments using CT scans is feasible in a majority of aerated ears. Detection of malleal ligaments improves with thinner slice thickness and cone-beam technique. Low interobserver agreement suggests the importance of experience and a need for standardized review.

Purpose: This study evaluated the feasibility of endoscopy in exposing the anterior surface of the malleus and tensor tympani tendon (ASMT) in children with congenital cholesteatoma (CC), and investigated the outcomes of hearing, postoperative complications, and residual or recurrent disease in endoscopic surgical approach cases., Methods: A retrospective case review was performed in one tertiary referral center. Twelve children with CC involving the ASMT were recruited, and their medical records were reviewed. All patients underwent either total endoscopic surgery (n = 3) or endoscope-assisted surgery (n = 9), and Potsic staging was adopted to classify CC according to its severity: stage I (n = 8), stage II (n = 2), and stage III (n = 2). The mean follow-up period was 15.5 ± 2.8 months. The visibility of the ASMT by endoscope assistance, audiological results, surgical and postoperative complications, and recidivism of CC were analyzed., Results: The ASMT was well visualized by endoscope assistance in all cases. No patient showed hearing deterioration at 3 months after surgery, and none experienced residual or recurrent disease during the follow-up period. Postoperative complications were not observed., Conclusions: Total endoscopic or endoscope-assisted surgery could help surgeons directly visualize the ASMT in children, with negligible risks of hearing deterioration, postoperative complications, and recurrent disease. Our study might suggest that endoscopic ear surgery should be considered in patients with CC in the ASMT.

Many living species of golden moles (Chrysochloridae) have greatly enlarged middle ear ossicles, believed to be used in the detection of ground vibrations through inertial bone conduction. Other unusual features of chrysochlorids include internally coupled middle ear cavities and the loss of the tensor tympani muscle. Our understanding of the evolutionary history of these characteristics has been limited by the paucity of fossil evidence. In this article, we describe for the first time the exquisitely preserved middle and inner ears of Namachloris arenatans from the Palaeogene of Namibia, visualised using computed tomography, as well as ossicles attributed to this species. We compare the auditory region of this fossil golden mole, which evidently did not possess a hypertrophied malleus, to those of three extant species with similarly sized ear ossicles, Amblysomus hottentotus, Calcochloris obtusirostris, and Huetia leucorhinus. The auditory region of Namachloris shares many common features with the living species, including a pneumatized, trabeculated basicranium and lateral skull wall, arteries and nerves of the middle ear contained in bony tubes, a highly coiled cochlea, a secondary crus commune, and no identifiable canaliculus cochleae for the perilymphatic duct. However, Namachloris differs from extant golden moles in the apparent absence of a basicranial intercommunication between the right and left ears, the possession of a tensor tympani muscle and aspects of ossicular morphology. One Namachloris skull showed what may be pneumatization of some of the dorsal cranial bones, extending right around the brain. Although the ossicles are small in absolute terms, one of the Huetia leucorhinus specimens had a more prominent malleus head than the other. This potentially represents a previously unrecognised subspecific difference., (© 2017 Wiley Periodicals, Inc.)

The anterior anchoring of the malleus of 30 extant species of Lagomorpha (rabbits, hares, pikas) has been studied on the basis of histological serial sections and µCT-scans. It is shown that former studies of Oryctolagus, Lepus, and Ochotona are incomplete, because the rostral part of the processus anterior of the malleus is always lacking due to damage of this extremely delicate structure. Our study shows that in perinatal stages of Leporidae the praearticulare develops a prominent processus internus that fits into a groove at the ventral side of the tegmen tympani; this "tongue and groove"-arrangement may act as a hinge. In adult stages, the rostral end of the praearticulare fuses synostotically with the medial process of the ectotympanic. Torsional strain produced by rotation around the axis of the middle ear ossicles at sound transmission must, therefore, be experienced by the extremely thin but highly elastic bony pedicle of the processus internus praearticularis. The free ending processus anterior of a late fetal Ochotona shows a short processus internus praearticularis, which does not articulate with the tegmen tympani. During postnatal development the middle ear of Ochotona becomes considerably remodelled: not only does excessive pneumatization of the tegmen tympani and tympanic cavity wall occur, but the short processus anterior is fused synostotically to a bone trabecula of the tegmen tympani meshwork. The thin and elastic bone bridges are not equivalent in Leporidae and Ochotonidae, that is, they must have evolved convergently. Fleischer's classification with Oryctolagus possessing a "freely mobile type" of middle ear ossicles cannot be supported by our observations. The same holds true for Ochotona, which does not represent a "freely mobile type" either. Thus, we suggest for the lagomorph middle ear ossicles a new category: the "bone elasticity type.", (© 2017 Wiley Periodicals, Inc.)

Isolated fracture of the handle of the malleus is a rare cause of conductive hearing loss and represents a challenge for the otolaryngologist in terms of past medical history, diagnostics, and therapy.

Human middle ears show large morphological variations. This could affect our perception of hearing and explain large variation in experimentally obtained transfer functions. Most morphological studies focus on capturing variation by using landmarks on cadaveric temporal bones. We present statistical shape analysis based on clinical cone beam CT (CBCT) scans of 100 patients. This allowed us to include surface information on the incudomallear (IM) complex (joint, ligaments and tendon not included) of 123 healthy ears with a scanning resolution of 150 μm and without a priori assumptions. Statistical shape modeling yields an average geometry for the IM complex and the variations present in the population with a high precision. Mean values, variation and correlations among anatomical features (length of manubrium, combined length of malleus head and neck, lengths of incus long and short process, enclosing angles, ossicular lever ratio, incudomallear angle, and principal moments of inertia) are reported and compared to results from the literature. Most variation is found in overall size and the angle between incus and malleus. The compact representation provided by statistical shape modeling is demonstrated and its benefits for surface modeling are discussed., (Copyright © 2016 Elsevier B.V. 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.

This article proposes a fully automated computational solution to segment the incus and malleus ear ossicles in conventional tri-dimensional X-ray computed tomography images. The solution uses a registration-based segmentation paradigm, followed by image segmentation refinement. It was tested against a dataset comprising 21 computed tomography volumetric images of the ear acquired using standard protocols and with resolutions varying from 0.162 × 0.162 × 0.6 to 0.166 × 0.166 × 1.0 mm(3). The images used were randomly selected from subjects who had had a computed tomography examination of the ear due to ear-related pathologies. Dice's coefficient and the Hausdorff distance were used to compare the results of the automated segmentation against those of a manual segmentation performed by two experts. The mean agreement between automated and manual segmentations was equal to 0.956 (Dice's coefficient), and the mean Hausdorff distance among the shapes obtained was 1.14 mm, which is approximately equal to the maximum distance between the neighbouring voxels in the dataset tested. The results confirm that the automated segmentation of the incus and malleus ossicles in tri-dimensional images acquired from patients with ear-related pathologies, using conventional computed tomography scanners and standard protocols, is feasible, robust and accurate. Thus, the solution developed can be employed efficiently in computed tomography ear examinations to help radiologists and otolaryngologists in the evaluation of bi-dimensional slices by providing the related tri-dimensional model., (© IMechE 2014.)

A new anatomically-accurate Finite Element (FE) model of the tympanic membrane (TM) and malleus was combined with measurements of the sound-induced motion of the TM surface and the bony manubrium, in an isolated TM-malleus preparation. Using the results, we were able to address two issues related to how sound is coupled to the ossicular chain: (i) Estimate the viscous damping within the tympanic membrane itself, the presence of which may help smooth the broadband response of a potentially highly resonant TM, and (ii) Investigate the function of a peculiar feature of human middle-ear anatomy, the thin mucosal epithelial fold that couples the mid part of the human manubrium to the TM. Sound induced motions of the surface of ex vivo human eardrums and mallei were measured with stroboscopic holography, which yields maps of the amplitude and phase of the displacement of the entire membrane surface at selected frequencies. The results of these measurements were similar, but not identical to measurements made in intact ears. The holography measurements were complemented by laser-Doppler vibrometer measurements of sound-induced umbo velocity, which were made with fine-frequency resolution. Comparisons of these measurements to predictions from a new anatomically accurate FE model with varied membrane characteristics suggest the TM contains viscous elements, which provide relatively low damping, and that the epithelial fold that connects the central section of the human manubrium to the TM only loosely couples the TM to the manubrium. The laser-Doppler measurements in two preparations also suggested the presence of significant variation in the complex modulus of the TM between specimens. Some animations illustrating the model results are available at our website (www.uantwerp.be/en/rg/bimef/downloads/tympanic-membrane-motion)., (Copyright © 2014 Elsevier B.V. All rights reserved.)

In Marfan's syndrome, which is a connective tissue disorder of hereditary origin, collagenous tissue development and bone synthesis are generally altered in addition to the occurrence of many systemic deformities. External ear, stapes, and vestibular aqueduct pathologies are reported as some of the otological deformities. However, the malleus and incus pathologies of the ear are not reported in any study. In the morphometric measurements carried out, the distance between the malleus head and manubrium was found to be 9.8 mm. When similar measurements were carried out for the incus, the distance between the upper part of the incus body and tip of the long process was found to be 6.9 mm. All of these measurements were detected to be greater than in normal people. It can be concluded from this study that in Marfan's syndrome, in addition to the musculoskeletal alterations particularly in bone synthesis, the ossicular chain in the middle ear is also affected., (Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.)

Objective: To retrospectively investigate the diagnostic value of the bent-lever planes in detecting abnormality of the malleus-incus complex., Study Design: Diagnostic test assessment., Setting: The study was conducted at the Shandong Medical Imaging Research Institute, Shandong University, Jinan, People's Republic of China., Subjects: Eighty-five ears in 74 patients with surgically proved abnormality of the malleus-incus complex., Materials and Methods: The bent-lever planes and direct axial images were reviewed by 2 radiologists. The radiologists assigned a value of abnormality or continuity to different parts of the malleus-incus complex. Differences in categorical data were evaluated with the McNemar test. The sensitivity, specificity, Youden index, and interobserver agreement were calculated., Results: There was no significant difference between bent-lever planes and direct axial images in identifying abnormality of the malleus-incus complex. The sensitivity ranged from 71.4% to 97.1%, and specificity ranged from 89.5% to 100.0%. The Youden index ranged from 0.609 to 0.971. The radiologists had almost perfect or substantial agreement in identifying the abnormality of different parts of the malleus-incus complex., Conclusion: The bent-lever planes do not add additional diagnostic value for experienced observers.

Background: Petrotympanic fissure (PTF) is a fissure in the temporal bone that runs from the temporomandibular joint (TMJ) to the tympanic cavity (TC). In PTF, the discomallear ligament (DML) connects the malleus in the tympanic cavity and the articular disc and capsule of the temporomandibular joint. PTF with the DML is a possible cause of aural symptoms related to temporomandibular joint dysfunction (TMD)., Purpose: To investigate the prevalence of different types of PTF in TMD using dental volumetric tomography (DVT) and determine whether PTF type correlates with age., Material and Methods: DVT scans in the sagittal planes of PTFs of 134 patients with TMD were examined for the types of PTF present. Three main PTF types were described: wide, tunnel-shaped structure (type 1); tunnel-shaped structure that is wide open in the PTF entrance to the mandibular fossa and gradually thins out in the tympanic cavity (type 2), tunnel-shaped structure that is wide open in the entrance of the mandibular fossa, with a middle region with a flat-shaped tunnel structure and a narrow exit in the tympanic cavity (type 3)., Results: In DVT scans, PTF types 1, 2 and 3 were seen in 67.2%, 1.5%, and 31.3% of cases, respectively. We found no significant relationship between age or gender and PTF type., Conclusion: The low percentage of type 2 PTF and high percentage of type 1 PTF must be taken into consideration during pre-surgical planning related to TMD. However, future well-designed clinical studies involving larger numbers of subjects will be necessary to confirm the findings of this study.

In the middle ear, a chain of three tiny bones (ie, malleus, incus, and stapes) vibrates to transmit sound from the tympanic membrane to the inner ear. Little is known about whether and how bone-resorbing osteoclasts play a role in the vibration of auditory ossicles. We analyzed hearing function and morphological features of auditory ossicles in osteopetrotic mice, which lack osteoclasts because of the deficiency of either cytokine RANKL or transcription factor c-Fos. The auditory brainstem response showed that mice of both genotypes experienced hearing loss, and laser Doppler vibrometry revealed that the malleus behind the tympanic membrane failed to vibrate. Histological analysis and X-ray tomographic microscopy using synchrotron radiation showed that auditory ossicles in osteopetrotic mice were thicker and more cartilaginous than those in control mice. Most interestingly, the malleal processus brevis touched the medial wall of the tympanic cavity in osteopetrotic mice, which was also the case for c-Src kinase-deficient mice (with normal numbers of nonresorbing osteoclasts). Osteopetrotic mice showed a smaller volume of the tympanic cavity but had larger auditory ossicles compared with controls. These data suggest that osteoclastic bone resorption is required for thinning of auditory ossicles and enlargement of the tympanic cavity so that auditory ossicles vibrate freely., (Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Purpose: Aim of this study was to examine any stapes fixation-related clinical, intraoperative and high-resolution computed tomography (HRCT) findings in children undergoing stapedotomy., Procedures: Detailed diagnostic assessment was performed in 12 children (18 ears) who underwent stapedotomy within the period 2005-2008., Results: Ear malformations such as malleus-incus anomalies, malleus-epitympanum fixation and absence of the stapedius tendon, small external auditory canal and auricle malformations were clinically and/or intraoperatively diagnosed. HRCT identified a petrous high jugular bulb and malformed inner auditory canal in 4 ears; however, it failed to recognize ossicular fixation. Systemic anomalies, namely kyphoscoliosis, esophageal atresia and finger malformations were identified in 2 children. Summing up, additional anatomic anomalies were found in 8 patients (66.7%)., Conclusions: Ear malformations may coexist in children with stapes fixation. Ossicular fixation is not easily recognized with HRCT, and therefore, ossicular mobility should always be tested intraoperatively. In a few cases, pediatric stapes fixation can coexist with systemic dysplasias; in such patients, additional referral to geneticists is recommended., (Copyright © 2011 S. Karger AG, Basel.)

Objective: Temporal bone imaging in children has several inherent limitations. Computed tomography has the disadvantage of ionizing radiation, possible sedation, cost and accessibility. Magnetic resonance imaging has most of these disadvantages, with the exception of radiation, and provides bone images of limited resolution. Recent advances in ultrasound have led to its increased application in numerous medical fields. The purpose of this study was to investigate the ability of four-dimensional ultrasound (4DUS) to image middle ear ossicles in vitro and determine if this technology should be adapted for future clinical use., Methods: Thirty cadaveric ossicles (10 malleus, 10 incus, and 10 stapes) were randomized and measured by two evaluators under a microscope. The ossicles were then immersed in a cold water bath and imaged, randomized, and measured using four-dimensional ultrasound by the same two evaluators. A separate cadaveric temporal bone, modified to allow the ultrasound probe to rest on the tympanic membrane, was imaged to visualize the ossicles in situ and evaluate whether or not the tympanic membrane and malleus would impede visualization of more medial structures., Results: Microscopic measurements were: malleus (h=8.0 mm+/-0.32, w=2.7 mm+/-0.20), incus (h=6.8 mm+/-0.41, w=5.3 mm+/-0.46), stapes (h=3.5 mm+/-0.34, w=2.4 mm+/-0.17). Inter-rater reliability was 0.8. Measurements were in agreement with previously published values. Ultrasound measurements were: malleus (h=8.0 mm+/-0.51, w=2.9 mm+/-0.27), incus (h=6.8 mm+/-0.49, w=5.5 mm+/-0.42), stapes (h=3.6 mm+/-0.41, w=2.5 mm+/-0.19). Inter-rater reliability was 0.7. Mean intra-class correlation coefficient for microscopic and ultrasound measurements was 0.7. Images of the ossicular chain in continuity in the temporal bone specimen were not as clear as images of individual ossicles that were disarticulated and imaged under water., Conclusions: 4DUS provides reasonable images of ossicles disarticulated and mounted in underwater medium. However, images of the intact ossicular chain in a modified cadaveric temporal bone were not as clear, making interpretation difficult. Further investigation into the development of a thinner ultrasound probe that can pass through the external auditory canal and into overcoming limitations of air in the middle ear cleft are warranted. This could allow for a clinically relevant, faster, lower cost and lower risk alternative to current imaging techniques., (Copyright 2010 Elsevier Ireland Ltd. All rights reserved.)

The middle ear is too complex a system for its function to be fully understood with simple descriptive models. Realistic mathematical models must be used in which structural elements are represented by geometrically correct three-dimensional (3D) models with correct physical parameters and boundary conditions. In the past, the choice of boundary conditions could not be based on experimental evidence as no clear-cut data were available. We have, therefore, studied the deformation of the tympanic membrane (TM) at its boundaries using X-ray microscopic computed tomography in human and gerbil while static pressure was applied to the ear canal. The 3D models of the TM and its bony attachments were carefully made and used to measure the deformation of the TM with focus on the periphery and the manubrium attachment. For the pars flaccida of the gerbil, the boundary condition can, for the most part, be described as simply supported. For the human pars flaccida, the situation is more complicated: superiorly, the membrane contacts the underlying bone more and more when pushed further inward, and it gradually detaches from the wall when sucked outward. In gerbil, the attachment of the TM to the manubrium can be described as simply supported. In human, the manubrium is attached underneath the TM via the plica mallearis and the contact of the TM with the bone is indirect. For both human and gerbil, a simple boundary condition for the peripheral edge of the pars tensa is not appropriate due to the intricate structure at the edge: the TM thickens rapidly before continuing into the annulus fibrosis which finally makes contact with the bone.

Objectives: To present an effective system for the evaluation and surgical management of localized attic cholesteatoma, as well as describing the follow-up of patients treated at our institution., Study Design: Retrospective review of single-institution experience., Methods: A total of 71 patients (71 ears) with localized attic cholesteatoma received atticotomies. Further surgical management was then carried out according to the extent of the cholesteatoma and whether the malleoincudal joint was preserved (type I) or not (type II). There were 27 type I patients and 44 type II patients. In all 71 patients, the lateral wall of epitympanum was rebuilt with tragal cartilage. The healing of the lateral wall of the attic and the tympanic membrane as well as the recovery of hearing level were assessed after the operation., Results: The follow-up periods lasted 3-6 years, with an average of 4.5 years. The healing of the lateral wall of the epitympanum was satisfactory in all 71 patients. According to pure tone audiometry conducted after the operation, the air-bone gap was <10 dB in 43 patients, <20 dB in 23 patients, <30 dB in 4 patients, and >30 dB in only 1 patient. No vertigo or tinnitus was experienced after the operation., Conclusions: The surgical management of localized attic cholesteatoma should be planed according to the extent of the cholesteatoma and especially the condition of the malleoincudal joint. In order to prevent a subsequent retraction pocket of the attic, it is important to rebuild the lateral wall of the attic with cartilage after clearing the cholesteatoma., (Copyright 2010 S. Karger AG, Basel.)

Malleus head fixation and otosclerosis causing conductive hearing loss are often difficult to differentiate by clinical features. Up to now exploratory anterior tympanotomy was necessary to distinguish these pathologies. The case of a 22-year-old male suffering from conductive hearing loss of the right ear is presented. Otosclerosis was suspected and high-resolution CT scanning of the petrous bone was performed. The diagnosis was confirmed radiologically by the detection of an isolated malleus head fixation. Instead of explorative anterior tympanotomy, radiological and audiological controls were combined for the follow-up.

The mean resonance frequency of the human middle ear under air conduction (AC) excitation is known to be around 0.8-1.2 kHz. However, studies suggest that the mean resonance frequency under bone conduction (BC) excitation is at a higher frequency around 1.5-2 kHz. To identify the cause for this difference, middle-ear responses to both AC and BC excitations were measured at the umbo and lateral process of the malleus using five human cadaver temporal bones. The resonance modes identified from these measurements, along with finite element analysis results, indicate the presence of two ossicular modes below 2 kHz. The dominant mode under AC excitation is the first mode, which typically occurs around 1.2 kHz and is characterized by a "hinging" ossicular motion, whereas the dominant mode under BC excitation is the second mode, which typically occurs around 1.7 kHz and is characterized by a "pivoting" ossicular motion. The results indicate that this second mode is responsible for the translational component in the malleus handle motion. The finding is also consistent with the hypothesis that a middle-ear structural resonance is responsible for the prominent peak seen at 1.5-2 kHz in BC limit data.

Objective: To evaluate the feasibility of localizing the internal auditory canal (IAC) and the facial nerve through the root of the zygoma, foramen spinosum and the head of the malleus in middle fossa approach with the assistance of high resolution computerized tomography (HRCT)., Methods: Eighteen human cadaveric temporal bones were scanned and measured by HRCT. Cadaver specimen were divided into two groups. Group A was studied first through a middle fossa approach to find out the relationship between the HRCT measurements and the anatomic measurements. Then 4 whole human cadaveric heads (8 temporal bones) of group B were dissected using a HRCT oriented middle fossa approach to localize IAC with the root of the zygoma, foramen spinosum and the head of the malleus as landmarks. The two measurement methods were analysed with the Paired-Sample T test, and the difference was thought to be statistical significant when P < 0.05., Results: In Group A, there were no statistical significant differences between the CT measurements and the anatomic measurements from the head of the malleus to other important anatomic structures. In group B, the operation was guided with CT measurements: the distance between the head of the malleus and the root of the zygoma, and the distance between the head of the malleus and foramen spinosum. Within the range 1.5 mm to 3.7 mm, the head of malleus was correctly localized. In seven out of the eight cases, the root of the zygoma, the head of the malleus and the internal auditory canal were in a straight line, whereas, in one case, there was an angle of 15 degrees between the root of zygoma -head of malleus line and head of malleus -internal auditory canal line., Conclusions: HRCT would provide more information on the distance relationship between the head of malleus and the root of the zygoma, foramen spinosum and the internal auditory canal. The head of the malleus could be localized through the root of the zygoma and foramen spinosum with HRCT and therefore the IAC could be exposed with the head of the malleus as a landmark in middle fossa approach when other landmarks were not recognizable.

The malleus-incus complex (MIC) is unique to mammalian hearing. To develop a comprehensive biomechanical MIC model for the human middle ear, measurements regarding its anatomical features are a necessity. Micro-scale X-ray computed tomography (micro-CT) imaging, which is known to be a suitable method for imaging high-density tissue such as middle-ear ossicles and surrounding bones, is used in this study to determine the three-dimensional (3-D) morphometry of the soft tissue attachments of the MIC. The MIC morphometry is based on their 3-D reconstruction from micro-CT image slices with resolutions ranging from 10 to 20 mum. The suspensory ligament and tendon attachments of the malleus and the incus as well as the incudomalleal joint (IMJ), are quantified in terms of dimensions, positions, and orientations for four human cadaver temporal bones. The malleus principal frame, the incus principal frame, and the MIC principle frame are calculated and the morphometry is reported in relation to each of these frames for the first time. The resulting values show significant variation across ear samples, suggesting that models of the MIC should be based on individual anatomy. The IMJ morphometry dimensions appear to be proportional to the ossicular mass. The micro-CT imaging modality is a nondestructive and relatively fast method for obtaining soft tissue morphometry and provides accurate anatomical features in relation to the principal axes of bones.

Objective: To review the surgical management and outcomes of patients with congenital absence of the oval window (CAOW) undergoing the oval window drill-out (OWD) procedure., Study Design and Setting: A retrospective chart review of patients with CAOW seen in a tertiary care otologic practice between 1991 and 2006., Patients/intervention: Patients with CAOW undergoing OWD procedure., Main Outcome Measures: Findings at surgery and preoperative and postoperative audiometric outcomes (air and bone conduction thresholds; speech reception threshold)., Results: Seventeen ears underwent OWD for CAOW. Four cases were aborted. For the 13 subject ears, average 1-month postoperative 4-tone air conduction and speech reception thresholds were significantly lower than preoperative thresholds. Long-term follow-up (average, 20 months) air conduction and speech reception thresholds were also significantly lower but showed a slight worsening of thresholds compared with the 1-month postoperative results. Speech discrimination scores and bone conduction thresholds remained stable., Conclusion: OWD may be a viable operation for patients with CAOW, although longer follow-up is needed. Given the mixed hearing results in the current patient series, we have tempered our enthusiasm for this operation. Technically challenging, this procedure nevertheless can improve patients' hearing with minimal morbidity. Revision surgery did not result in improved outcome.

The auditory anatomy of the Florida manatee (Trichechus manatus latirostris) was investigated using computerized tomography (CT), three-dimensional reconstructions, and traditional dissection of heads removed during necropsy. The densities (kg/m3) of the soft tissues of the head were measured directly using the displacement method and those of the soft tissues and bone were calculated from CT measurements (Hounsfield units). The manatee's fatty tissue was significantly less dense than the other soft tissues within the head (p<0.05). The squamosal bone was significantly less dense than the other bones of the head (p<0.05). Measurements of the ear bones (tympanic, periotic, malleus, incus, and stapes) collected during dissection revealed that the ossicular chain was overly massive for the mass of the tympanoperiotic complex.

The densities of middle ear ossicles of golden moles (family Chrysochloridae, order Afrosoricida) were measured using the buoyancy method. The internal structure of the malleus was examined by high-resolution computed tomography, and solid-state NMR was used to determine relative phosphorus content. The malleus density of the desert golden mole Eremitalpa granti (2.44 g/cm3) was found to be higher than that reported in the literature for any other terrestrial mammal, whereas the ossicles of other golden mole species are not unusually dense. The increased density in Eremitalpa mallei is apparently related both to a relative paucity of internal vascularization and to a high level of mineralization. This high density is expected to augment inertial bone conduction, used for the detection of seismic vibrations, while limiting the skull modifications needed to accommodate the disproportionately large malleus. The mallei of the two subspecies of E. granti, E. g. granti and E. g. namibensis, were found to differ considerably from one another in both size and shape.

Among congenital ossicular anomalies without external ear atresia, malleus fixation is least common. We report a case of congenital malleus fixation by a bony bar connecting the malleus neck to the posterior tympanic wall, which was depicted on thin-section CT scans.

Purpose: To describe the variation in size and shape of the anterior epitympanic recess and to discuss pathologic processes that affect this space., Methods: Axial CT scans of the temporal bones of 31 adults and 19 children were reviewed retrospectively to ascertain the morphology and size of the anterior epitympanic recess. Selected confirmed disease processes involving this space were studied., Results: The anterior epitympanic recess, which is consistently identified on axial CT scans, is either single or multicelled. In our study, it was made up of a solitary cell in 61 of 100 ears. Side-to-side symmetry in shape was present in 78 of 100 cases. The size of a solitary air cell ranged from 1.0 to 7.0 mm., Conclusions: The configuration of the anterior epitympanic recess is readily affected by a persistent stapedial artery, by facial nerve schwannomas, by hemangiomas of the facial nerve canal in the geniculate region, and by congenital and acquired cholesteatomas. Familiarity with the CT anatomy of this space facilitates recognition of these pathologic processes at an early stage.

In eight patients, with a known air-conduction hearing loss, three-dimensional images of the ossicular chain were constructed based on heavily overlapping high resolution CT-slices, obtained from a spiral CT data set. High quality three-dimensional images could be obtained in all eight patients. Supplementary information was derived from these three-dimensional images in three patients; in one, this supplementary information had therapeutic importance. The slight image quality loss in spiral-CT of the temporal bone, compared with conventional CT, is in some cases largely compensated by the possibility of rendering high quality secondary reconstructions.

This study was conducted to assess the usefulness and limitations of high-resolution CT for diagnosing the ossicular chain in the middle ear. The CT images in this study were obtained in as much detail as possible and 2 direction images. Preoperative CT findings of the ossicular chain were compared with operative findings in 26 patients with ossicular defects. Preoperative detection of the complete defect of the malleus head and the body and long process of the incus by high-resolution CT was possible in all cases, while detection of the defect of the manubrium of the malleus and superstructure of the stapes could be made in 33.3 and 60%, respectively. The defect of the incudostapedial joint (1 case) and partial defect of the stapes crus (2 cases) could not be diagnosed correctly by preoperative estimation.

Radiographic findings in the inclined lateral projection are presented. This view provides detail of the malleus and incus which is not provided on any other view and also preserves the visualization of temporal bone anatomy seen by routine lateral projection. The frequent occurrence of ossicular pathology in inflammatory and traumatic diseases of the ear requires the meticulous radiographic examination of the ossicles provided by this projection. Patient positioning is uncomplicated and comfortable.

A right malleus fixed to the roof of the tympanic cavity in a 1,600-year-old skull is described. The possible etiolgy of this condition is examined and the literature concerning recent and paleopathology of the middle ear ossicles is reviewed.

Eight clinical situations are best examined by polytomography, namely, ossicular chain disruption, malleus fixation, assessing the extent of footplate fixation, delineating cochlear otospongiosis, postoperative studies of unsuccessful cases, developing an anatomic map preoperatively with particular reference to the intratympanic course of the facial nerve, ruling in or out the rare closure of the round window by otospongiosis, and differentiation of the congenital footplate fixation from true otospongiosis. We discuss each of these situations briefly.

Serous otitis media is a capricious entity that can cause conductive deafness. The condition is most common in children, who often cannot describe the attending symptoms of deafness, fullness, and pressure. The basic contributing factor is inadequate function of the eustachian tube. Function improves as the child approaches 12 years of age. Underlying factors such as infections, adenoidal hypertrophy, and allergic states also must be managed. The otitis media may be treated medically or surgically.