First biocompatibility margins for optical stimulation at the eardrum via 532-nm laser pulses in a mouse model.

Hearing impairment affects ∼460 million people worldwide. Conservative therapies, such as hearing aids, bone conduction systems, and middle ear implants, do not always sufficiently compensate for this deficit. The optical stimulation is currently under investigation as an alternative stimulation strategy for the activation of the hearing system. To assess the biocompatibility margins of this emerging technology, we established a method applicable in whole-mount preparations of murine tympanic membranes (TM). We irradiated the TM of anesthetized mice with 532-nm laser pulses at an average power of 50, 89, 99, and 125 mW at two different locations of the TM and monitored the hearing function with auditory brainstem responses. Laser-power-dependent negative side effects to the TM were observed at power levels exceeding 89 mW. Although we did not find any significant negative effects of optical stimulation on the hearing function in these mice, based on the histology results further studies are necessary for optimization of the used parameters.

Arterial Anomalies of the Middle Ear: A Pictorial Review with Clinical-Embryologic and Imaging Correlation.

The differential diagnosis of a red and/or pulsatile retrotympanic mass includes aberrant internal carotid artery, persistent stapedial artery (PSA), glomus tympanicum, and dehiscent jugular bulb. By recognizing the features of aberrant internal carotid artery and PSA on high-resolution computed tomography, these entities can be assessed by the radiologist. PSA is further classified by type because each type demonstrates a unique set of imaging features in addition to features common to all types. Although rarely encountered, it is important to reliably and consistently detect these anomalies because failure to do so can lead to disastrous surgical outcomes.

Middle ear microvascularization: an "in vivo" endoscopic anatomical study.

PURPOSE: To describe the in vivo vascularization of middle ear by an endoscopic point of view, particularly focusing on the medial wall of tympanic cavity and incudostapedial region (ISR). STUDY DESIGN: Case series with surgical videos review and anatomical description. METHODS: 48 videos from exclusive endoscopic middle ear surgery performed at the University Hospital of Modena from November 2015 to July 2017 were reviewed. Data about anatomy of vessels, and blood flow direction (BFD) were collected in an appropriate database for further analyses. RESULTS: 48 cases were included in the present study. In 18/48 patients (37,5%), a clearly identifiable inferior tympanic artery (ITA) was present, running just anteriorly to the round window (RW), with a superior BFD (65% of cases) from the hypotympanic region toward the epitympanum. Some promontorial variants were described in 67% of cases and the most common finding was a mucosal vascular network with a multidirectional BFD. On the ISR, an incudostapedial artery (ISA) was detected in 65% of cases with BFD going from the long process of the incus (LPI) toward the pyramidal eminence in the majority of cases. CONCLUSION: The vascular anatomy and BFD of the medial wall of the tympanic cavity can be easily studied in transcanal endoscopy. ITA (with a superior BFD in most cases) and ISA (with a main BFD from the incus to the stapes) are the most constant identifiable vessels.

[Pulsatile Tinnitus due to an Aberrant Internal Carotid Artery in the Middle Ear:A Case Report].

We report a rare case of aberrant internal carotid artery in the middle ear. The patient was a 30-year-old man with pulsatile tinnitus. MRA and 3D-CTA revealed an aberrant course of the internal carotid artery in the middle ear. 3D-CTA proved useful for radiographic diagnosis, leading to the observation of an aberrant internal carotid artery passing the foramen. We discuss the diagnosis and management of such patients.

Aberrant Internal Carotid Artery in the Tympanic Cavity.

OBJECTIVES: Presence of aberrant internal carotid artery (ICA) in the tympanic cavity is a very rare case and therefore the diagnosis is a challenge. Here, the authors aimed to address the importance of the diagnosis since the intervention to the middle ear and implants is increasing in number and this condition may lead to life-threatening bleeding. METHODS: Between 2012 and 2016, among the patients referred to the authors' Radiology Department from the Department of Otolaringology for the evaluation of the temporal region for various indications, the authors reported this anomaly in 6 patients and multidetector computerized tomography of these 6 patients and magnetic resonance imaging of 2 were assessed in detail. RESULTS: The mean age of the 6 patients was 28.8 and aberrant ICA abnormality was observed in 2 patients bilaterally and 4 patients unilaterally on the right side. In 1 patient ICA was not totally regressed and observed as hypoplastic. In one of the patients, dehiscence was evident between ICA and the cochlea. Moreover, in 1 patient the contralateral ICA was not observed. CONCLUSION: Although rare, aberrant ICA is an abnormality that should be kept in mind by the clinicians and the radiologists, since it leads to abundant bleeding when undiagnosed before the surgical interventions.

Internal carotid arterial canal size and scaling in Euarchonta: Re-assessing implications for arterial patency and phylogenetic relationships in early fossil primates.

Primate species typically differ from other mammals in having bony canals that enclose the branches of the internal carotid artery (ICA) as they pass through the middle ear. The presence and relative size of these canals varies among major primate clades. As a result, differences in the anatomy of the canals for the promontorial and stapedial branches of the ICA have been cited as evidence of either haplorhine or strepsirrhine affinities among otherwise enigmatic early fossil euprimates. Here we use micro X-ray computed tomography to compile the largest quantitative dataset on ICA canal sizes. The data suggest greater variation of the ICA canals within some groups than has been previously appreciated. For example, Lepilemur and Avahi differ from most other lemuriforms in having a larger promontorial canal than stapedial canal. Furthermore, various lemurids are intraspecifically variable in relative canal size, with the promontorial canal being larger than the stapedial canal in some individuals but not others. In species where the promontorial artery supplies the brain with blood, the size of the promontorial canal is significantly correlated with endocranial volume (ECV). Among species with alternate routes of encephalic blood supply, the promontorial canal is highly reduced relative to ECV, and correlated with both ECV and cranium size. Ancestral state reconstructions incorporating data from fossils suggest that the last common ancestor of living primates had promontorial and stapedial canals that were similar to each other in size and large relative to ECV. We conclude that the plesiomorphic condition for crown primates is to have a patent promontorial artery supplying the brain and a patent stapedial artery for various non-encephalic structures. This inferred ancestral condition is exhibited by treeshrews and most early fossil euprimates, while extant primates exhibit reduction in one canal or another. The only early fossils deviating from this plesiomorphic condition are Adapis parisiensis with a reduced promontorial canal, and Rooneyia and Mahgarita with reduced stapedial canals.

The blood supply to the canine middle ear.

Current descriptions of the anatomy of the blood supply to the canine middle ear are either incomplete or inconsistent, particularly in regards to the vascular branches in close proximity to the temporomandibular articulation (TMJ). To further investigate this blood supply, dissections (n = 9), corrosion casts (n = 4), and computed tomography (n = 8) of canine temporal regions/ears were performed. The goal of this study was to identify and describe branches of the external carotid and maxillary arteries in close proximity to the TMJ that supply the middle ear of the dog. Specific focus was placed on the constancy and origin of the canine rostral tympanic artery since this artery was anticipated to arise from the maxillary artery and enter a foramen at the medial aspect of the mandibular fossa adjacent to the TMJ. New anatomical variations of three canine arteries are described in this study. (1) The rostral tympanic artery is a branch of the temporomandibular ramus and is accommodated by a small foramen located within a depression medial to the temporomandibular joint. (2) A pharyngeal branch of the caudal deep temporal artery was identified. (3) The origin of the caudal auricular artery occurred opposite the lingual artery in 25.8% of dissected specimens, contrary to published descriptions. Anat Rec, 299:907-917, 2016. © 2016 Wiley Periodicals, Inc.

Anatomical variations and relations of large blood vessels to the tympanic cavity.

PURPOSE: The aim of this study was to assess the protrusion of the upper bulb of the internal jugular vein (UBJV) and the internal carotid artery (ICA) into the cavum tympani, the thickness and the structure of the bone wall that separates these blood vessels from the middle ear cavity, as well as the bone wall absence between these blood vessels and the cavum tympani. METHODS: The study included a total of 150 samples of temporal bones of elderly people, both sexes. The methods used in the study were anatomic and histologic, while analyses were done by a surgical microscope. RESULTS: In 38 (25.3%) of the 150 studied temporal bones, the UBJV protruded into the cavum tympani, elevating its bottom. In 3 (7.8%) of the samples the bulb had a high position, thus filling the hypotympanum, and closing the lower half of the fenestra rotunda. The most frequent thickness of the bone wall that separates the ICA and the Eustachian tube was 2 mm (48.2%), less frequently it was 2-4 mm (29.6%), while least frequently it was of paper consistency (22.2%). CONCLUSION: High jugular bulb, aberrant ICA and anomalies of their wall structures are a pitfall and risk for middle ear surgery. Awareness of this variation is very important in the presurgical evaluation of the temporal bone to avoid vascular injury.

[The state of microcirculation in the middle ear structures at different stages of the treatment of the patients presenting with chronic otitis media].

The present work was designed to study dynamics of blood circulation in the tympanic membrane and tympanic cavity mucosa of 92 patients (105 ears) presenting with otosclerosis, adhesive non-perforative otitis media, and different stages of chronic suppurative otitis media. Normal characteristics of tympanic microcirculation were determined in 22 otologically healthy volunteers (30 ears). Laser Doppler flowmetry with the use of a specially designed probe (the outer diameter: 1.9 mm) was applied. The results of Doppler flowmetry varied in ontologically healthy subjects. The same circulation parameters in the vessels of the microcirculatory bed of the postero-superior quadrant of the tympanic membrane in the patients presenting with chronic suppurative otitis media at the stage of remission, otosclerosis, and adhesive non-perforative otitis media did not significantly differ from those of otologically healthy subjects. The blood flow was shown to increase in the tympanic membrane of the majority of the patients during the postoperative period (within 2nd to 4th weeks after types I-III tympanoplasty); thereafter, it either decreased or returned to the baseline level by weeks 6-8. Four months after the improvement of perfusion parameters of tympanic cavity mucosa and the arrest of exacerbation of mesotympanitis, characteristics of microcirculation in tympanic cavity mucosa were not significantly different from those of the patients with adhesive perforative otitis media. It is concluded that laser Doppler flowmetry may be used as an objective non-invasive technique for the study of microcirculation in the tympanic membrane and tympanic cavity mucosa.

Investigation of middle ear pressure changes during prone position under general anesthesia without using nitrous oxide.

PURPOSE: The effects of different body positions on the middle ear were reported in several studies, but there are no data about the effects on patients under general anesthesia. The aim of this study is to determine the effect of prone position on middle ear pressure (MEP) during general anesthesia without using nitrous oxide. METHODS: Twenty patients under general anesthesia during prone position were included in the study. The performed anesthesia method was the same for all patients. Remifentanil was used for analgesia instead of nitrous oxide. MEPs were measured 5 times with a middle ear analyzer: before induction (BI), after intubation (AI), after turned to the prone position (PP1), at the end of the prone position (PP2), and after returned to the supine position (SP). Duration of prone position was also recorded. RESULTS: Of the 20 patients were 11 women and 9 men with a 49 ± 13 mean age. BI-AI, AI-PP1, PP1-PP2, and PP2-SP comparisons of both MEPs were statistically significant (P < 0.0001). Right mean MEPs were BI, -1 ± 23 daPa; AI, 41 ± 51 daPa; PP1, 124 ± 76 daPa; PP2, 152 ± 59 daPa; and SP, 63 ± 29 daPa; whereas left mean MEPs were BI, -24 ± 55 daPa; AI, 28 ± 34 daPa; PP1, 132 ± 67 daPa; PP2, 162 ± 48 daPa; and SP, 70 ± 89 daPa. Significant increases were detected at the start and continuation of the prone position. The mean duration of prone position was 98 ± 51 per minute. CONCLUSIONS: The significant MEP increases during the prone position under general anesthesia depend on a number of reasons. Among them are inhaler agents, pressure changes in mucosal blood vessels due to venous congestion, and the mastoid bone volume. Further researches are required to determine and explain the mechanisms of increase in MEP during prone position.

Aberrant internal carotid artery in the middle ear.

An aberrant internal carotid artery (ICA) in the middle ear space can present in 1% of the population. The clinical diagnosis can be difficult as most patients with this anomaly are either asymptomatic or have nonspecific clinical symptoms and signs. Moreover the diagnosis can easily be missed and only discov.ered when injurey occur to the ICA during middle ear surgey with resulting life-threatning complications. A knowledge of this anomaly and its differential diagnosis is of high importance to any practitioner dealing with otologic diseases and performing otologic surgeries. We report a 7-year-old girl with a right aberrant ICA presenting with hearing loss and review published studies concerning this disease entity presentation, diagnosis, and management.

Intratympanic aberrant and hypoplastic carotid artery.

Intratympanically aberrant internal carotid artery(ICA) is a rarely seen vascular abnormality. We present here the combination of aberration and prominent hypoplasia of the ICA in a case. Intratympanic aberrant ICA, which is rarely cited as a cause of tinnitus and hearing loss, should be known as a reason to be kept in mind as it may lead to life-threatening complications. Generally, it has been defined upon massive bleeding during myringotomy, ear surgery or biopsy procedure. In this article, the audiological and radiological studies confirmed with CT and MR angiography conducted on an aberrant and hypoplastic internal carotid artery that was identified under the manubrium mallei in a 28-year-old, young male patient who presented with complaints about hearing loss and fullness in the left ear were presented along with a literature review.

Gross anatomy and arterial vascularization of the tympanic cavity and osseous labyrinth in mid-gestational bovine fetuses.

This study aims to determine morphological features of certain aural formations, varietal characteristics, and arterial supply in fetal development period in cattle. For this purpose, ears of 10 bovine fetuses in mid-gestation were evaluated. Organ morphology and vascularization in prenatal life were investigated by using corrosion cast technique. It was observed that some aspects of osseous formation and vascular organization in middle and inner ears were not developed completely in the first half of gestation; in addition, cochlea did not its snail-like structure yet, lateral semicircular canal was rather low compared to others and auditory ossicles did not take its final shape. The feeding blood vessels of inner ear were found to demonstrate three different distribution patterns, whereas feeding pattern in middle ear was very similar in many specimens. The presence of stapedial artery was also identified. Differences and similarities with other some species were assessed in terms of both general morphological structure and vascular organization. From this regard, it is thought that this study will constitute a comparative model for both humans and other species and provide morphological contributions since there is not sufficient literature on species-specific ear morphology in the field of veterinary anatomy in contrast to the abundance of studies on humans.

Middle ear aneurysm treated with an innovative, vessel-preserving, aneurysm-occluding stent.

Middle ear aneurysms are rare and difficult to treat. An innovative, parent vessel-preserving, aneurysm occlusion stent is a treatment alternative. It redirects blood flow away from the aneurysm, resulting in stasis within, and ultimate aneurysm thrombosis. Concurrent coiling is not needed with this stent, eliminating the risk of coils extruding or migrating, or acting as a nidus for infection in the middle ear. We review a successful treatment using this device.

Perfusion and diffusion limitations in middle ear gas exchange: the exchange of CO2 as a test case.

A long standing debate on perfusion/diffusion limitations in the context of middle ear (ME) gas exchange was revisited using data obtained from previous iso-pressure gas-exchange measurements in different mammals. We tried to determine whether the exchange of CO(2) in the ME is limited by perfusion or by diffusion by comparing the mass specific cardiac output (msQ) and the mass specific initial CO(2) flow rate into air-washed MEs (msV(i) CO(2)) of rabbits and rats. Based on previously published allometry at rest, the msQ was 0.154 mL/(min g) in rabbits (mean body weight: 2800 g) and 0.259 mL/(min g) in rats (mean body weight: 179.1 g); msV(i) CO(2) (Delta t=0) was 0.109+/-0.047 microL/(h g) in rabbits (n=16) and 0.170+/-0.094 microL/(h g) in rats (n=9). Similar ratios were found when an allometric comparison was made between the ratio of msV(i) CO(2) (Delta t=0) (approximately 0.64), and the ratio of msQs (approximately 0.59) in rabbits and rats. If the active mucosal surface areas of MEs of rabbits and rats are directly proportional to their masses as are the masses of their hearts and if their msQs are proportional to the rates of blood flows in the ME mucosa, these results support the assumption that the exchange of CO(2) in the ME of mammals is mainly perfusion (and not diffusion) dependent.

Pressure changes in the human middle ear without opening the eustachian tube.

CONCLUSION: By means of a direct, though non-invasive experiment on healthy humans we could demonstrate that middle ear (ME) pressure decreases when the eustachian tube (ET) does not open. Thus with a very simple method the basic theory of continuous gas loss from the ME into the circulation and the replenishment of the loss through the ET could be validated. OBJECTIVES: To record changes in ME pressure over a period of time in normal human ears, while the ET is kept closed. SUBJECTS AND METHODS: On-line tympanometry was carried out in three subjects, who refrained from swallowing for 20-120 min. RESULTS: During the time when the ET was kept closed by refraining from swallowing, tympanometric monotonous pressure decrease was recorded. Once the tested subject could not refrain from swallowing any longer and swallowed again, ME pressure equalized immediately.

Ethanol embolization of auricular arteriovenous malformations: preliminary results of 17 cases.

BACKGROUND AND PURPOSE: Because of the relatively rare and extremely varied clinical presentations, arteriovenous malformations (AVMs) involving the auriculae are technically challenging clinical entities to diagnose and, ultimately, manage. The purpose of our study was to present our initial experience of ethanol embolization in a series of 17 patients with auricular AVMs and assess the interim therapeutic outcomes of this method. MATERIALS AND METHODS: Our study group consisted of 17 patients. Transcatheter arterial embolization and/or direct percutaneous puncture embolization were performed. Pure or diluted ethanol was manually injected. Follow-up evaluation was obtained on the basis of physical examination and angiography at 3- to 4-month intervals and telephone questionnaire at 1-month intervals in all patients. RESULTS: During the 29 ethanol embolization procedures, the amount of ethanol used ranged from 4 to 65 mL. The obliteration of ulceration, hemorrhage, pain, infection, pulsation, and bruit in most of the patients was obtained. The reduction of redness, swelling, and warmth was achieved in all of the patients, and 15 of the patients achieved downstaging of the Schobinger status. According to the angiographic findings, AVMs were devascularized 100% in 3 patients, 76% to 99% in 5 patients, 50% to 75% in 6 patients, and less than 50% in 3 patients. The most common complications were reversible necrosis and blister. CONCLUSIONS: Ethanol embolization has proved efficacious and safe in the treatment of auricular AVMs and has the potential to be accepted as the primary mode of therapy in the management of these lesions.