Visualization of bone formation in sheep's middle ear by using fluorochrome sequential labelling (FSL).

One factor for the lacking integration of the middle ear stapes footplate prosthesis or the missing healing of stapes footplate fractures could be the known osteogenic inactivity. In contrast, it was recently demonstrated that titanium prostheses with an applied collagen matrix and immobilised growth factors stimulate osteoblastic activation and differentiation on the stapes footplate. Regarding those findings, the aim of this study was to evaluate the potential of bone regeneration including bone remodeling in the middle ear. Ten one-year-old female merino sheep underwent a middle ear surgery without implantation of middle ear prostheses or any other component for activating bone formation. Post-operatively, four fluorochromes (tetracycline, alizarin complexion, calcein green and xylenol orange) were administered by subcutaneous injection at different time points after surgery (1 day: tetracycline, 7 days: alizarin, 14 days: calcein, 28 days: xylenol). After 12 weeks, the temporal bones including the lateral skull base were extracted and histologically analyzed. Fluorescence microscopy analysis of the entire stapes with the oval niche, but in particular stapes footplate and the Crura stapedis revealed evidence of new bone formation. Calcein was detected in all and xylenol in 60% of the animals. In contrast, tetracycline and alizarin could only be verified in two animals. The authors were able to demonstrate the osseoregenerative potential of the middle ear, in particular of the stapes footplate, using fluorescence sequence labelling.

Finite element analysis of conductive hearing loss caused by fixation and detachment of ligament and tendon in the middle ear.

BACKGROUND AND OBJECTIVE: The fixation of ligament and tendon of the middle ear often occurs after chronic otitis media surgery. However, there are relatively few studies on the effect of ligament and tendon on sound transmission in the human middle ear. Here, the finite element model and lumped parameter model are used to study the effect of ligament and tendon fixation and detachment on sound transmission in human ear. METHODS: In this paper, the finite element model including the external auditory canal, middle ear and simplified inner ear is used to calculate and compare the middle ear frequency response of the normal and tympanosclerosis under pure tone stimulation. In addition, the lumped parametric model is taken into account to illustrate the effect of ligament and tendon stiffness on the human ear transmission system. RESULTS: The results indicate that the motion of the tympanic membrane and stapes is reduced by ligament and tendon fixation. Although ligament and tendon detachment have a limited effect in the piston-motion direction, the stability of motion in the plane perpendicular to the piston-motion direction is significantly reduced. Most significantly, the ligament and tendon fixation cause a hearing effect of about 18 dB, which is greater in the plane perpendicular to the piston-motion direction after ligament and tendon detachment than in the piston-motion direction. CONCLUSIONS: In this study, the calculation accuracy of the lumped parameter and the finite element model is studied, and the effect of ligament and tendon on hearing loss is further explored through the finite element model with high calculation accuracy, which is helpful to understand the role of ligament and tendon in the sound transmission mechanism of the human middle ear. The study of ligament and tendon on conductive hearing loss provides a reference for clinical treatment of tympanosclerosis.

Finite element modelling of the human middle ear using synchrotron-radiation phase-contrast imaging.

Finite element (FE) models of the middle ear often lack accurate geometry of soft tissue structures, such as the suspensory ligaments, as they can be difficult to discern using conventional imaging modalities, such as computed tomography. Synchrotron-radiation phase-contrast imaging (SR-PCI) is a non-destructive imaging modality that has been shown to produce excellent visualization of soft tissue structures without the need for extensive sample preparation. The objectives of the investigation were to firstly use SR-PCI to create and evaluate a biomechanical FE model of the human middle ear that includes all soft tissue structures, and secondly, to investigate how modelling assumptions and simplifications of ligament representations affect the simulated biomechanical response of the FE model. The FE model included the suspensory ligaments, ossicular chain, tympanic membrane, the incudostapedial and incudomalleal joints, and the ear canal. Frequency responses obtained from the SR-PCI-based FE model agreed well with published laser doppler vibrometer measurements on cadaveric samples. Revised models with exclusion of the superior malleal ligament (SML), simplification of the SML, and modification of the stapedial annular ligament were studied, as these revised models represented modelling assumptions that have been made in literature.

Using Stapes Velocity to Estimate the Efficacy of Mechanical Stimulation of the Round Window With an Active Middle Ear Implant.

OBJECTIVE: To test a method to measure the efficacy of active middle ear implants when coupled to the round window. METHODS: Data previously published in Koka et al. ( Hear Res 2010;263:128-137) were used in this study. Simultaneous measurements of cochlear microphonics (CM) and stapes velocity in response to both acoustic stimulation (forward direction) and round window (RW) stimulation (reverse direction) with an active middle ear implant (AMEI) were made in seven ears in five chinchillas. For each stimulus frequency, the amplitude of the CM was measured separately as a function of intensity (dB SPL or dB mV). Equivalent vibrational input to the cochlea was determined by equating the acoustic and AMEI-generated CM amplitudes for a given intensity. In the condition of equivalent CM amplitude between acoustic and RW stimulation-generated output, we assume that the same vibrational input to the cochlea was present regardless of the route of stimulation. RESULTS: The measured stapes velocities for equivalent CM output from the two types of input were not significantly different for low and medium frequencies (0.25-4 kHz); however, the velocities for AMEI-RW drive were significantly lower for higher frequencies (4-14 kHz). Thus, for RM stimulation with an AMEI, stapes velocities can underestimate the mechanical input to the cochlea by ~20 dB for frequencies greater than ~4 kHz. CONCLUSIONS: This study confirms that stapes velocity (with the assumption of equivalent stapes velocity for forward and reverse stimulation) cannot be used as a proxy for effective input to the cochlea when it is stimulated in the reverse direction. Future research on application of intraoperative electrophysiological measurements during surgery (CM, compound action potential, or auditory brainstem response) for estimating efficacy and optimizing device coupling and performance is warranted.

[A preliminary study on wideband acoustic immittance of infants with normal bilateral middle ear function at the age of 1-5 months].

Objective:To explore preliminary characteristics of wideband acoustic immittance of 1- to 5-month-old infants who have bilateral normal middle ear function, so as to contribute to the clinical application of WAI test in the evaluation of middle ear function in infants. Methods:1- to 5-month-old infants were included. After the normal function of bilateral middle ear was determined by otoacoustic emission and high frequency acoustic immittance test, WAI test was performed and the relevant data were collected and analyzed. Results:There was no statistical difference in absorbance at the same frequency between the left ear and right ear of each group（P>0.05）. Absorbance of 4000 Hz increased at first and then decreased with the growth of physiological age, and the sound energy absorption rate of other frequencies decreased except 2670 Hz and 3364 Hz. Conclusion:The outcome of this study shows that it is necessary to establish the national normal value of WAI in 1- to 5-month-old infants who have bilateral normal middle ear function. The purpose of the development of middle ear system is to ensure that sounds in the speech frequency range can be transmitted and heard more effectively.

Are suspensory ligaments important for middle ear reconstruction?

As the resolution of 3D printing techniques improves, the possibility of individualized, 3-ossicle constructions adds a new dimension to middle ear prostheses. In order to optimize these designs, it is essential to understand how the ossicles and ligaments work together to transmit sound, and thus how ligaments should be replicated in a middle ear reconstruction. The middle ear ligaments are thought to play a significant role in maintaining the position of the ossicles and constraining axis of rotation. Paradoxically, investigations of the role of ligaments to date have shown very little impact on middle ear sound transmission. We explored the role of the two attachments in the gerbil middle ear analogous to human ligaments, the posterior incudal ligament and the anterior mallear process, severing both attachments and measuring change in hearing sensitivity. The impact of severing the attachments on the position of the ossicular chain was visualized using synchrotron microtomography imaging of the middle ear. In contrast to previous studies, a threshold change on the order of 20 dB across a wide range of frequencies was found when both ligaments were severed. Concomitantly, a shift in position of the ossicles was observed from the x-ray imaging and 3D renderings of the ossicular chain. These findings contrast with previous studies, demonstrating that these ligaments play a significant role in the transmission of sound through the middle ear. It appears that both mallear and incudal ligaments must be severed in order to impair sound transmission. The results of this study have significance for middle ear reconstructive surgery and the design of 3D-printed three-ossicle biocompatible prostheses.

Effect of middle ear gelfoam on hearing and healing process after tympanoplasty: A prospective randomized case-control study.

PURPOSE: This prospective randomized case-control study was performed to compare the surgical outcomes of our swing-door overlay tympanoplasty with or without absorbable gelatine sponge (AGS, gelfoam) packing in the middle ear cavity, according to the surgical procedure. METHODS: Fifty-seven patients who underwent swing-door overlay tympanoplasty by a single surgeon were enrolled in the study. The data of 30 patients of the gelfoam-packing group (GPG) and 27 patients of the non-gelfoam-packing group (NGPG) were prospectively collected and compared. RESULTS: Closure of the tympanic membrane was found to be successful in all patients at postoperative 3 months evaluation. NGPG showed a statistically better healing process compared to GPG; earlier epithelialization and less fascia edema in NGPG than in GPG (P < 0.05). The air-bone gap (ABG) measured at postoperative 1 and 2 months was smaller in NGPG than GPG, although there were no statistical differences. CONCLUSION: This study revealed earlier healing process and faster recovery of ABG in NGPG, thereby indicating that the gelfoam in the middle ear may interfere with both hearing recovery and the healing process of neodrum.

Endoscopic Ear Surgery: Redefining Middle Ear Anatomy and Physiology.

Middle ear anatomy and physiology is highly complex, yet familiarity is important to perform middle ear surgery and understand surgically relevant ventilation pathways of the ear compartments. The middle ear is divided into five subspaces: the mesotympanum, the retrotympanum posteriorly, the epitympanum superiorly, the protympanum anteriorly, and the hypotympanum inferiorly. The Eustachian tube plays a crucial role in maintaining middle ear aeration and atmospheric pressure. There are two independent aeration routes of the epitympanum. Thanks to the advent of the endoscope, this anatomic and physiologic knowledge has allowed one to understand the pathophysiology of ear diseases, improving surgical concepts.

A design-thinking approach to therapeutic translation: tympanic regeneration.

PURPOSE OF REVIEW: Clinician researchers face the pressures of meeting academic benchmarks combined with advancing new therapies to patients. The vast majority of drug discoveries fail in translation. A new method of meeting the challenges of preclinical therapeutic translation is presented using the example of tympanic regeneration. RECENT FINDINGS: The key to a design-thinking approach to therapeutic translation is to 'begin with the end in mind' by widening the scope of the problem, with multiple points of view, to not only understand the disease but the context for the patient and the health system in which it occurs. Idea for therapeutics should be tested in relevant models early and once proof of efficacy is established, translational milestones that represent the greatest risk, such as safety and toxicity should be addressed first. It is important to seek the feedback of industry early to understand what milestones should be best addressed next with limited academic resources. Whenever proceeding, guidelines for maintaining scientific reproducibility should be followed to minimize risk of failure during transfer into industry. SUMMARY: A Design-thinking approach addresses the potential failures in drug discovery and preclinical translation.

Proposal of a new scoring system for equalization problems during freediving.

OBJECTIVE: Scuba diving and freediving are popular activities around the world, and their growth has increased the frequency of related pathology. A good ability to equalize is of paramount importance for diving. This is especially true for freediving, during which dive time is limited to just one breath. Even though equalization disorders are quite common in divers, a scoring system does not exist to date. In this paper we propose a new scoring system for equalization problems of freedivers: the EP score, shorthand for "equalization problems." METHODS: We administered the EP score assessment to 40 Italian freediving spearfishermen who were divided in two groups: Group A comprised 20 freedivers complaining of equalization problems and multiple barotraumas but totally asymptomatic in their everyday lives. These individuals had already received medical treatment and nasal surgery without improvement and then had undergone Eustachian tube balloon dilation. Group B comprised 20 healthy freedivers without any history of equalization disorders. We performed a statistical analysis to evaluate the reliability of this scoring system and to evaluate its usefulness in diagnosis and follow-up. RESULTS: Our data show substantial statistical differences between healthy freedivers and freedivers complaining of equalization disorders (Z-Score = -5.396 at p ⟨ 0.05); data do not show any statistical difference between healthy freedivers and patients successfully treated by Eustachian tube balloon dilation (U-value = 152.5 and Z-Score= -1.271 at p ⟨ 0.05). CONCLUSION: The EP score assessment seems to be a reliable tool to quantify equalization disorders during freediving and to evaluate how the difficulty varies over time and after treatment. Since equalization disorders could be present in different populations, the EP score assessment could be applicable to a wider group.

Test-Retest Reliability of Multicomponent Tympanometry at 226-, 678-, and 1000-Hz Probe Tones Over 10 Sessions.

Purpose Numerous studies are testimony to the pivotal role of multicomponent tympanometry in diagnosis and differential diagnosis of auditory pathologies, not only of the middle ear but also the inner ear. Repeated measurements using multicomponent tympanometry have been used as a measure for stapedial tendon preservation during middle ear surgeries. However, such applications would produce reliable results only when multicomponent tympanometry produces replicable results across sessions. Nonetheless, there is dearth of studies exploring the test-retest repeatability of multicomponent tympanometry across multiple sessions using various probe tones. Therefore, this study aimed at examining the test-retest reliability of multicomponent tympanometry across 10 different sessions for 226-, 678-, and 1000-Hz probe-tone frequencies. Method The study included 28 healthy adults in the age range of 18 to 25 years. All participants underwent multicomponent (susceptance and conductance) tympanometry using 226-, 678-, and 1000-Hz probe tones. Results Multicomponent tympanometry showed excellent test-retest reliability for all parameters of 226- and 678-Hz probe tones. The probe tone of 1000 Hz produced excellent test-retest reliability for most of the parameters. Conclusions The clinical recording of multicomponent tympanometry over multiple sessions is more reliable when using 226- and 678-Hz probe tones. Hence, these probe tones lend themselves to possible applications requiring multiple recordings, such as evaluation of treatment outcomes or preservation of middle ear structures during surgery.

[Human ear finite element model study of the effects of ear canal and middle ear cavity on air conduction and bone conduction].

Objective:To study the influence of the ear canal and middle ear cavity on air conduction and bone conduction. Method:A finite element model of the human middle ear was established. By establishing the external ear canal and the middle ear cavity, we evaluated the effects of the external canal and the middle ear cavity on air conduction and bone conduction. Result:In air conduction, the external canal improved the stapes response at the frequency range of 0.5 kHz to 6 kHz, and the maximum increase was 11 dB at 3 kHz. The middle ear cavity mainly reduced the response of stapes at mid-low frequency, with the drops of 2-4 dB under 2 kHz; in bone conduction, ear canal slightly reduced the low-frequency response, but increased the response of the stapes at the mid-high frequency, with a maximum increase of 1.9 dB at 1.5 kHz. The middle ear cavity mainly increased the stapes response at mid-frequency near 1.5 kHz, with a maximum increase of 2.5 dB. Conclusion:Our results show that, in air conduction, the ear canal significantly increases the middle-frequency response, while the middle ear cavity decreases the low-mid frequency response. Whereas, the ear canal and the middle ear cavity have slightly effect on bone conduction.

Frequency-specific activation of the peripheral auditory system using optoacoustic laser stimulation.

Hearing impairment is one of the most common sensory deficits in humans. Hearing aids are helpful to patients but can have poor sound quality or transmission due to insufficient output or acoustic feedback, such as for high frequencies. Implantable devices partially overcome these issues but require surgery with limited locations for device attachment. Here, we investigate a new optoacoustic approach to vibrate the hearing organ with laser stimulation to improve frequency bandwidth, not requiring attachment to specific vibratory structures, and potentially reduce acoustic feedback. We developed a laser pulse modulation strategy and simulated its response at the umbo (1-10 kHz) based on a convolution-based model. We achieved frequency-specific activation in which non-contact laser stimulation of the umbo, as well as within the middle ear at the round window and otic capsule, induced precise shifts in the maximal vibratory response of the umbo and neural activation within the inferior colliculus of guinea pigs, corresponding to the targeted, modelled and then stimulated frequency. There was also no acoustic feedback detected from laser stimulation with our experimental setup. These findings open up the potential for using a convolution-based optoacoustic approach as a new type of laser hearing aid or middle ear implant.

Tri-dimensional model for ventilation tube permeability.

PURPOSE: Ventilation tubes (VT) in the tympanic membrane expose the middle ear (ME) to the external auditory canal and its content. It carries the risk of penetration of contaminated material and could provide a pathway for the delivery of drugs into the ME. The aim of this study was to use a printed 3D-model of the external auditory canal (EAC) and ME to assess the permeability of various VTs to different fluids. METHODS: CT scan of the external and ME was 3D-reconstructed and printed. Five different types of VT were inserted in the model's tympanic membrane and the minimal pressure for penetration to the ME was measured. Liquids with different viscosities, including commonly used ear drops, were tested. RESULTS: Water passed through the standard 1.14 mm diameter VTs after filling the EAC with a volume of 2 ml and through a narrower grommet or a T-tube after filling the canal with 2.5 ml. Soapy-water had the highest penetration in all VTs (1-2 ml). The initial volume of dexamethasone needed for penetration was 2.5 ml in the standard tubes. It did not pass at any volume through the narrow grommet or the T-tube. CONCLUSION: In the printed 3D-model, the volume of most solutions, including water, required to provide enough pressure in order to pass through the VTs was as high as the EAC volume or exceeded it. Soapy water had the highest penetrance while Dexamethasone needed volume of 2.5 ml to pass through the VT, questioning its reliability as a passive drug delivery channel to the ME.

Including auditory tube function on models is relevant to assess water exposure after tympanostomy tubes-Multiphase computerized fluid dynamics model.

INTRODUCTION: Myringotomy with tympanostomy tube is the most common otologic surgery and some patients are still advised to avoid water. However, there is no evidence supporting this, with published papers questioning the need for this advice. METHODS: A Multiphase Computational Fluid Dynamics (CFD) model was created using computerized tomography images of a child's healthy ear. It was then used to study the flow of fluids through the external ear, tympanic cavity, and auditory tube, with and without submersion. RESULTS: The model accurately described the behavior of the air retained in the patient's nasopharynx and tympanic cavity. A simulated elevation of pressure in the external auditory canal without submersion, without increase of pressure in the nasopharynx, demonstrated that fluids promptly crossed the tympanostomy tube into the middle ear. However, simulated elevation of pressure in the external auditory canal with concurrent elevation of air pressure in the nasopharynx during submersion did not lead to passive tube opening nor to any detectable flow through the tympanostomy tube. CONCLUSIONS: In the model, submersion increases pressure in the nasopharynx which offsets the pressure in the external auditory canal. So, in the absence of a pressure gradient, no passive tubal opening took place, and no air or fluid flow was detected through the transtympanic tube. This model now includes the exhaust function of the auditory tube in the model and shows its relevance.

Cervical Vestibular-Evoked Myogenic Potentials in Sedated Toddlers

Abstract Introduction Cervical vestibular-evoked myogenic potentials (cVEMPs) are difficult to test in toddlers who cannot follow instructions or stay calm. Objective Due to the growing need for vestibular testing in very young children as a part of a delayed walking assessment battery, this study aimed to provide a solution to this problem by recording the cVEMPs in toddlers during sedation. Method The cVEMPs measures were assessed in 30 toddlers aged 12 to 36 months with normal motormilestones. They were sedated with chloral hydrate. Then, the head was retracted ~ 30° backward with a pillow under the shoulders, and turned 45° contralateral to the side of stimulation to put the sternocleidomastoid (SCM)muscle in a state of tension. Results The P13 and N23 waves of the cVEMPs were recordable in all sedated toddlers. The cVEMPs measures resulted in the following: P13 latency of 17.5 ± 1.41 milliseconds, N23 latency of 25.58 ± 2.02 milliseconds, and peak-topeak amplitude of 15.39 ± 3.45 μV. One-sample t-test revealed statistically significant longer latencies and smaller amplitude of the toddlers' cVEMPs relative to the normative data for adults. Conclusions The difficulty of cVEMPs testing in toddlers can be overcome by sedating them and attaining a position that contracts the SCM muscle. However, the toddlers' recordings revealed delayed latencies and smaller amplitudes than those of adults.

Effects of Total Intravenous Anesthesia and Low- and High-Flow Anesthesia Implementation on Middle Ear Pressure.

BACKGROUND: The middle ear is an air-filled lacuna in the temporal bone. Inhaled anesthetic agents increase the pressure of this lacuna. Therefore, attention must be paid in choosing not only anesthetic agents but also anesthetic method. AIM: This study compared the effects of high-flow total intravenous anesthesia (TIVA) and low- and high-flow desflurane anesthesia on middle ear pressure. STUDY DESIGN: Randomized prospective double-blind study. METHODS: In this retrospective double-blind study, 90 patients (20-65 years old) scheduled to undergo elective thyroidectomies were divided into three randomized anesthesia groups: high-flow desflurane (Group I), low-flow desflurane (Group II), and high-flow TIVA (propofol, remifentanil) (Group III). The hemodynamic and respiratory parameters and tympanometry were measured before induction (T1), 10 minutes after intubation (T2), 10 minutes before the end of the operation (T3), and 5 (T4), 10 (T5), 15 (T6), and 30 (T7) minutes after the operation. RESULTS: No statistically significant differences were found in the age, gender, weight, height, body mass index, surgery duration, and anesthetic duration (p > 0.05). There were no statistically significant differences at T1, T3, T4, T5, T6, and T7 (p > 0.007), but there was a significant difference at T2 (p < 0.001), with Groups II and III having lower pressure than Group I (p < 0.001). CONCLUSION: The high-flow desflurane group had higher postinduction middle ear pressure values. Therefore, low-flow anesthesia and TIVA can be used more safely in middle ear surgeries, provided that a well-equipped anesthetic device and appropriate monitoring conditions are available.

Treatment of cholesteatoma with intact ossicular chain: anatomic and functional results.

SUMMARY: In case of cholesteatoma with intact ossicular chain, the primary aims of surgery are complete removal of the cholesteatoma matrix and reconstruction of a dry and safe middle ear; if possible, ossicular chain continuity and therefore the preoperative hearing must be preserved. The aim of this retrospective study is to present the experience of the U.O.C. Otorinolaringoiatria Universitaria of University of Bari "Aldo Moro" in treatment of intact ossicular chain cholesteatoma with Bondy modified radical mastoidectomy (BMRM) and canal wall up tympanoplasty (CWUT). The study group was composed of 65 subjects affected by cholesteatoma with intact ossicular chain. Mean age was 40.7 years (range 6-79), with 42 males and 23 females. 30 patients were treated by a BMRM and 35 by CWUT, in 22 cases without mastoidectomy and in 13 cases with mastoidectomy. Mean follow-up was 24.25 months. In the BMRM group, no cases of residual cholesteatoma located in the middle ear space were detected; at follow-up, 1 patient developed a retraction pocket (3.33%), 1 patient showed a small epidermal cysts of the tympanic membrane (3.33%) and 3 patients (10%) experienced otorrhoea. In CWUT, residual cholesteatoma was detected in 2 cases (5.7%); at follow-up, 3 patients presented recurrent cholesteatoma (8.57%; 2, 6 and 8 years after surgery), 3 cases a retraction pocket (8.57%) and one case otorrhoea (2.86%). Statistical analysis showed a significant higher number of residual cholesteatoma in CWUT (p 0.005) and differences in terms of long-term complications. No significant changes in hearing occurred post-operatively or at 1 year follow-up in either group. The current trend in our centre is to perform BMRM when indicated and CWUT preferably without mastoidectomy in case of mesotympanic cholesteatoma with normal OC.

Middle Ear Pressures in Wind Instrument Musicians.

OBJECTIVES: This study aimed to assess if playing wind instruments leads to a measurable increase in middle ear pressure during note generation and to provide evidence to clinicians to advise musicians undergoing middle ear surgery. STUDY DESIGN: An observational cohort study of 40 volunteers in 7 different wind instrument categories underwent tympanometry at rest and during note production. SETTING: Community. PATIENTS: Recreational musicians aged over 18 years recruited from the student body attending Birmingham University, UK. INTERVENTION: None. MAIN OUTCOME MEASURES: Tympanometry is used as a noninvasive measure of middle ear pressure. The pressure at which peak compliance occurred was taken as an indirect measure of middle ear pressure. The data produced at rest and during note production was statistically analysed with paired t testing and significance set at a p value less than 0.01. RESULTS: Overall a statistically significant increase in middle ear pressure change of 0.63 mm Hg (p = 0.0001) during note production was identified. Musicians playing the oboe and trumpet demonstrate the largest increase in middle ear pressure of 1.46 mm Hg (p = 0.0053) and 0.78 mm Hg (p = 0.0005) respectively. CONCLUSION: The data provided by this study gives evidence for the first time that playing wind instruments does increase middle ear pressure. Although the clinical significance of this is yet to be determined the authors would advise that musicians who undergo otological procedures should refrain from playing their instruments until full recovery has been achieved as advised by their clinician following direct microscopic review.

[The topographical and anatomical characteristic of the anterior part of the external auditory passage and the tympanic cavity]. / Topografoanatomicheskaia kharakteristika perednego otdela naruzhnogo slukhovogo prokhoda i barabannoi polosti.

The objective of the present work was to overview the currently available literature data on microtopographic anatomy of the anterior portion of the middle ear and the external auditory passage. Manipulations on these structures during miringoplasty surgery appear to be the most difficult and laborious operations because this space is anatomically very narrow and curved; moreover, it contains the important intimate structures of the middle ear and is located very close to the temporomandibular joint. The knowledge of microsurgical anatomy of the anterior part of the middle ear and the external auditory passage is paramount in the context of the improvement of the professional skills of the surgeons. The current literature data provide a basis for the conclusion that many aspects of microsurgical anatomy of the anterior part of the tympanic cavity and the external auditory passage thus far remain poorly explored. This assertion is especially true as regards the relief of the mucous membrane overlying these structure and their supply with arterial blood. Further clarification of these aspects is needed.