Pilot Study to Detect Changes in Blood Flow in the External Auditory Meatus During Hemodialysis.

Blood flow to internal organs is reported to fall during hemodialysis (HD). As such, noninvasive monitoring devices are required to detect changes in perfusion, which could then be used for therapeutic interventions. We report on a pilot study monitoring blood flow in the outer auditory meatus. We measured the maximum pulse wave amplitude and indicators of blood flow by analyzing red and green color changes in the outer auditory meatus from video recordings made using an otoscope fitted with a digital camera during HD treatments. We studied 61 patients, 43 (71.5%) male, mean age 64.9 ± 12.7 years. Weight fell from 72.8 ± 22.5 kg predialysis to 71.5 ± 22.1 kg postdialysis (P < 0.001). BP did not significantly change (predialysis 142 ± 29/67 ± 18 to 143 ± 25/68 ± 17 mm Hg postdialysis). The maximum pulse wave amplitude in the external auditory meatus fell from 0.21 (0.1-0.55) to 0.14 (0.04-0.4) after 90 min, P < 0.001, and remained low thereafter, and the change at the end of the dialysis session was associated with percentage weight loss (r = -0.37, P = 0.003). Green and red pixel values did not change (predialysis 0.339 [0.333-0.345] to 0.302 [0.291-0.33] post, and 0.301 [0.293-0.328] predialysis to 0.339 [0.334-0.347] post, respectively). This pilot study showed that the maximum pulse wave amplitude measured in the external auditory meatus fell during the dialysis session, and that the fall was associated with fluid removal. This could potentially lead to the development of a monitoring device, which could fit in the ear and record during the dialysis session.

The Human Cochlear Aqueduct and Accessory Canals: a Micro-CT Analysis Using a 3D Reconstruction Paradigm.

OBJECTIVE: We sought to study the anatomic variations of the cochlear aqueduct and its accessory canals in human temporal bones using micro-CT and a 3D reconstruction paradigm. More knowledge about the anatomic variations of these structures, particularly at the basal turn of the cochlea and round window niche, may be important to better preserve residual hearing as well as the neural supply during cochlear implant surgery. METHODS: An archival collection of 30 human temporal bones underwent micro-CT and 3D reconstruction. A surface enhancement paradigm was applied. The application displays reconstructed slices as a 3D object with realistic 3D visualization of scanned objects. Virtual sectioning or "cropping" of the petrous bone presented subsequent areas. Thereby, the bony canals could be followed from inside the basal turn of cochlea and middle ear to the jugular foramen. RESULTS: The cochlear aqueduct was always paralleled by an accessory canal containing the inferior cochlear vein. It ran from the basal turn of the cochlea and exited laterally in the jugular foramen. In 70% of the cases, a secondary accessory canal was observed and it derived mostly from a depression or infundibulum located in the floor of the round window niche. This canal also exited in the jugular foramen. The secondary accessory canal occasionally anastomosed with the primary accessory canal suggesting that it contains a vein that drains middle ear blood to the cranial sinus. CONCLUSION: Micro-CT with 3D surface reconstruction paradigm offers new possibilities to study the topographic anatomy of minor details in the human inner ear. The technique creates simulated transparent "castings" of the labyrinth with a coinciding surface view through enhancement of contrast between boundaries. Accessory canals that drain blood from the cochlea, spiral ganglion, and middle ear could be characterized three-dimensionally.

A new evaluation of heat distribution on facial skin surface by infrared thermography.

OBJECTIVE: The aim of this study was to identify the facial areas defined by thermal gradient, in individuals compatible with the pattern of normality, and to quantify and describe them anatomically. METHODS: The sample consisted of 161 volunteers, of both genders, aged between 26 and 84 years (63 ± 15 years). RESULTS: The results demonstrated that the thermal gradient areas suggested for the study were present in at least 95% of the thermograms evaluated and that there is significant difference in temperature between the genders, racial group and variables "odontalgia", "dental prothesis" and "history of migraine" (p < 0.05). Moreover, there was no statistically significant difference in the absolute temperatures between ages, and right and left sides of the face, in individuals compatible with the pattern of normality (ΔT = 0.11°C). CONCLUSIONS: The authors concluded that according to the suggested areas of thermal gradients, these were present in at least 95% of all the thermograms evaluated, and the areas of high intensity found in the face were medial palpebral commissure, labial commissure, temporal, supratrochlear and external acoustic meatus, whereas the points of low intensity were inferior labial, lateral palpebral commissure and nasolabial.

Histopathology of inner ear malformations: Do we have enough evidence to explain pathophysiology?

OBJECTIVE: To investigate the histopathology of inner ear malformations (IEMs) in order to explain their pathophysiology. METHOD: Light microscopy was used to study 33 specimens exhibiting various IEMs in the collection of the Otopathology Laboratory at Harvard University's Massachusetts Eye and Ear Infirmary. RESULTS: The investigation found 18 incidences of cochlear hypoplasia (CH) (3 CH-I, 10 CH-II, 5 CH-III), 11 incomplete partitions (IPs) (5 IP-I, 6 IP-II), 2 vestibular dilatations, and 2 cases of cochlear nerve aplasia. The IP-I cases had characteristic defective endosteums, while the IP-II cases showed hydropic changes in the scala vestibuli. The CH cases were small in size externally, with normal or defective internal architecture. CONCLUSION: In combination with embryological data, these findings suggest that cases of CH-III and CH-IV are most probably genetically predetermined to be small in size, and that development of the membranous labyrinth stops at a point earlier than normal, so that it is shorter. At the time of complete ossification, this results in a cochlea with small external dimensions and normal internal architecture. In CH-I and CH-II cases, there is arrested development of the internal architecture, in addition to a small cochlea; it is most likely that in these cases, there is a severely defective vascular supply from the internal auditory canal (IAC). IP-I may be the result of a defective vascular supply from the blood vessels of the IAC. In IP-II, an enlarged endolymphatic sac (EES) appears to be the genetic abnormality that causes the other abnormalities, as it allows high pressure to be transmitted into the cochlea and vestibule. In IP-III, the pathophysiology appears to be an abnormal vascular supply from the middle ear mucosa, caused by a genetic abnormality and resulting in a thinner otic capsule and the absence of the modiolus.

Wearable Sensing of In-Ear Pressure for Heart Rate Monitoring with a Piezoelectric Sensor.

In this study, we developed a novel heart rate (HR) monitoring approach in which we measure the pressure variance of the surface of the ear canal. A scissor-shaped apparatus equipped with a piezoelectric film sensor and a hardware circuit module was designed for high wearability and to obtain stable measurement. In the proposed device, the film sensor converts in-ear pulse waves (EPW) into electrical current, and the circuit module enhances the EPW and suppresses noise. A real-time algorithm embedded in the circuit module performs morphological conversions to make the EPW more distinct and knowledge-based rules are used to detect EPW peaks. In a clinical experiment conducted using a reference electrocardiogram (ECG) device, EPW and ECG were concurrently recorded from 58 healthy subjects. The EPW intervals between successive peaks and their corresponding ECG intervals were then compared to each other. Promising results were obtained from the samples, specifically, a sensitivity of 97.25%, positive predictive value of 97.17%, and mean absolute difference of 0.62. Thus, highly accurate HR was obtained from in-ear pressure variance. Consequently, we believe that our proposed approach could be used to monitor vital signs and also utilized in diverse applications in the near future.

[Blood flow measurement and clinical usefulness of the temporal fascial scar tissue flap and the periosteal scar tissue flap in posterior canal wall reconstructed tympanoplasty for the mastoid cavity problem in the postoperative ear].

In the postoperative ear, following reconstructive tympanoplasty for a mastoid cavity problem, a very important key is to maintain a stable reconstructed posterior canal wall with the bone plate and cartilage in the posterior canal wall. The authors manage reconstruction of the posterior canal wall with the temporal fascial scar tissue flap (TFSF) and the temporal periosteal scar tissue flap (TPSF) to ensure obtaining a stable posterior canal wall and a tympanic membrane graft. Well-vascularized TFSF and TPSF enable us to acquire a solid reconstructed posterior canal wall because of the secure blood supplies to the flaps. In order to investigate the blood supplies of TFSF and TPSF, we employed laser Doppler blood flowmeters and measured blood flow in the flaps in 20 cases of posyoperative ears treated for a mastoid cavity problem. The blood supplies to both flaps were good, with the blood supply to the TFSF being statistically better than in the case of the TPSF. These findings suggested that the TFSF and TPSF were a reliable source of local well-vascularized tissue which were pliable and could facilitate the creation of a stable posterior canal wall. Furthermore it seems the good blood supply was linked to the prompt postoperative healing, the avoidance of postoperative infection, and good hearing improvement postoperatively.

Reconstruction of the external auditory canal using the random flap technique and laser Doppler evaluation.

BACKGROUND: The external auditory canal is one of the most difficult sites to reconstruct after tumor resection. In general, fascia transplantation is used to reconstruct defects of the external auditory canal, but this method is associated with scar formation and prolonged wound healing. Scar tissue might cause stenosis in the external auditory canal and hypoacusis, and wound healing is further delayed by radiation and chemotherapy. OBJECTIVE: To examine the safety of a random flap for reconstruction of an external auditory canal based on blood flow evaluation using a laser Doppler system. METHODS: Ten healthy volunteers were enrolled in this study to compare blood flow in the face, back, and behind the ear using a laser Doppler system. Two cases of external auditory canal reconstruction are presented. RESULTS: Blood flow behind the ear was abundant compared with that in the back. Blood flow in the face was higher than that behind the ear or on the back. CONCLUSION: Blood flow in the random flap was easily evaluated using the laser Doppler method. Based on our findings, we propose the random flap to reconstruct the external auditory canal after tumor resection.

Robustness, specificity, and reliability of an in-ear pulse oximetric sensor in surgical patients.

For many years, pulse oximetry has been widely used in the clinical environment for a reliable monitoring of oxygen saturation ( SpO2) and heart rate. But since common sensors are mainly placed to peripheral body parts as finger or earlobe, it is still highly susceptible to reduced peripheral perfusion, e.g., due to centralization. Therefore, a novel in-ear pulse oximetric sensor (placed against the tragus) was presented in a prior work which is deemed to be independent from perfusion fluctuations due to its proximity to the trunk. Having demonstrated the feasibility of in-ear SpO2 measurement with reliable specificity in a laboratory setting, we now report results from a study on in-ear SpO2 in a clinical setting. For this, trials were performed on 29 adult patients undergoing surgery. In-ear SpO2 data are compared with SaO2 data obtained by blood gas analysis, and with three reference pulse oximeters applied to the finger, ear lobe, and forehead. In addition, we derived an SpO2-independent perfusion index by means of the wavelengths used. The feasibility and robustness of in-ear SpO2 measurement is demonstrated under challenging clinical conditions. SpO2 shows good accordance with SaO2, a high level of comparability with the reference pulse oximeters, and was significantly improved by introducing a new algorithm for artifact reduction. The perfusion index also shows a good correlation with the reference data.

Investigation of Pulse Transit Times utilizing multisite reflectance photoplethysmography under conditions of artificially induced peripheral vasoconstriction.

Pulse Transit Time (PTT) is the time it takes for an arterial pulsation to travel from the heart to a peripheral site. In recent times, PTT has been advocated as a marker for assessing increased vascular resistance. However, the reliability of PTT as a marker for cardiovascular risks and its inverse relation to beat-to-beat blood pressure is still being investigated. In order to validate the technique as a reliable marker of vascular resistance, PTT measurements were made using photoplethysmographic (PPG) signals obtained from multiple measurement sites in 12 healthy volunteers undergoing right hand immersion in ice water for 30 secs. PTT measurements were made from the ear canal (EC), the left (LIF) and right index fingers (RIF) using custom made photoplethysmographic probes. Activation of the sympathetic nervous system during the ice water immersion caused an increase in vascular resistance, which is associated with an increase in mean arterial pressure and a decrease in PTT in all measurement sites. However, the change in PTT was much larger in the RIF when compared to the LIF and the EC. This demonstrates the cerebral flow autoregulation and the profound peripheral vasoconstriction seen in the right hand. After the ice immersion period, the mean PTT measured from the EC returned to baseline, whereas the LIF PTT exceeded baseline values. This is due to the local vasodilation resulted from the activation of a thermoregulation mechanism.

Devepopment of an optical probe to investigate the suitability of measuring photoplethysmographs and blood oxygen saturation from the human auditory canal.

Pulse oximetry has become a standard for patient monitoring in the operating room, and the finger is the most common site used for monitoring blood oxygen saturation (SpO2). However, SpO2 measurements made from extremities such as the finger, ear lobe and toes become susceptible to inaccuracies, when patients become hypothermic, hypovolemic and vasoconstrictive. This is due to the week arterial pulsations detected in these conditions. To overcome this limitation, the external auditory canal has been proposed as an alternative monitoring site for estimating SpO2, on the hypothesis that this central site will be better perfused. A dual wavelength optoelectronic sensor along with a processing system was developed to investigate the suitability of measuring photoplethysmographic (PPG) signals and SpO2 values in the human auditory canal. A pilot study was conducted on 12 healthy volunteers to validate the developed sensor. The red and infrared PPG signals obtained from all the volunteers were of very good quality. The SpO2 values recorded from the ear canal were compared with simultaneously acquired data from a commercial finger pulse oximeter. The results show good correlation between the commercial pulse oximeter and the custom made ear canal sensor (r(2) = 0.825).

Spontaneous intracranial hypotension syndrome accompanied by bilateral hearing loss and venous engorgement in the internal acoustic canal and positional change of audiography.

Hearing loss, tinnitus, and vertigo are very common complaints in otolaryngology practice. Here, we describe spontaneous intracranial hypotension (SIH) as a curable reason of hearing loss, tinnitus, and vertigo. A 29-year-old woman presented to the emergency room with nausea, dizziness, vertigo, instability, hearing loss, tinnitus, and neck and back pain. Cranial computed tomography, magnetic resonance imaging (MRI), and lumbar puncture were performed. The patient stated that the hearing loss and tinnitus became worse after effort or standing for prolonged times. Therefore, we performed audiogram in sitting and standing positions. The tinnitus severity index was used to evaluate tinnitus. Lumbar puncture revealed no cerebrospinal fluid, and cerebrospinal fluid could be obtained by aspiration. Cranial MRI showed dural thickness and venous engorgement in the internal acoustic canals bilaterally. Audiography showed worse hearing capacity in standing position than in sitting position and revealed especially low-frequency hearing loss bilaterally. The patient's tinnitus severity index was 48 of 60. The patient was diagnosed as having SIH and treated with autologous blood punch. Cranial MRI and audiogram were normal after the treatment. The patient had no tinnitus after the treatment. Spontaneous intracranial hypotension, which may cause Ménière syndrome-like symptoms, is a curable reason of hearing loss, tinnitus, and vertigo. In addition, the fluctuation of the hearing loss with positional changes supports the use of positional audiometry when evaluating hearing loss-related SIH. Venous engorgement in the internal acoustic canal may be related to the symptoms.

Arteriovenous malformation of the external ear: a case report.

Arteriovenous malformation (AVM) is a direct communication between an artery and vein without capillary connections and it is mainly found in the intracranial region. However, in an extracranial region, an AVM of the external ear is relatively uncommon. Recently, we experienced a case of an AVM in the external ear. A 20-year-old male patient presented with pulsatile tinnitus over the past 7 months and a reddish and pulsatile mass of the left external ear. We successfully treated the patient for the AVM in the external ear by complete excision after preoperative selective embolization.

Benign vascular lesions involving the external ear canal.

Benign vascular lesions include various forms whose classification has created some controversies in the literature. The observation of two rare cases of vascular bulge of the external ear canal prompted us to analyze the essential features of these lesions. One case was observed during an episode of otitis media, the other one was an incidental finding, and both are still on follow-up without treatment. The lesions are unmodified after 4 and 10 years, respectively. Vascular malformations can be differentiated from vascular tumors since they are present at birth, are generally stable, and do not involute. An attending strategy is justified unless symptoms occur.

Co-expression of different angiogenic factors in external auditory canal cholesteatoma.

OBJECTIVE: Although external auditory canal cholesteatoma (EACC) was first described in 1850, its cause remains surprisingly unclear. Angiogenesis, the formation of new blood vessels, is essential to normal development and wound healing in adults. Abnormal regulation of angiogenesis has been implicated in the pathogenesis of several disorders. The aim of this study was to analyse angiogenesis regulator expression in EACC. MATERIALS AND METHODS: Cryostat sections of 13 investigated EACC tissue samples and normal control tissue were immunostained for angiogenic hepatocyte growth factor (HGF)/scatter factor (SF), its c-Met receptor and vascular endothelial growth factor (VEGF) using a standard streptavidin-biotin complex procedure. Staining against von Willebrand factor (vWF) served as an endothelial marker. Statistical analysis was performed semiquantitatively. RESULTS: The assayed angiogenic factors were all present in the EACC tissue, and partly overexpressed. vWF was detected in the apical layers of the matrix epithelium. Positive immunoreactivity for c-Met and VEGF was detectable in all layers of the EACC epithelium; however, adjacent tissue did not express c-Met and VEGE. HGF/SF was predominantly expressed in the adjacent perimatrix tissue and fibroblasts in particular were stained positive. CONCLUSIONS: The presence of vWF in the apical part of the matrix depicted the attempt at angiogenesis in this part of the EACC. The detection of VEGF and c-Met in the epithelial part of the EACC implied that their origin may be epithelial, while HGF/SF may be secreted or stored in the adjacent mesenchymal EACC tissue. The angiogenic factors investigated seem to play an important role in establishing that EACC occurs by modulation of angiogenesis.

Spontaneous arteriovenous malformation of the external auditory meatus.

Arteriovenous malformations (AVM) of the head and neck are rare. They usually occur intracranially and derive their vascular supply from the intracranial vessels. In the English literature there has not been any documented case of AVMs in and around the external auditory meatus (EAM). The authors present the first case, a spontaneous AVM deriving its vascular supply from the posterior auricular artery. The diagnostic difficulties and management strategies of spontaneous AVMs are discussed.

The quantitative analysis of the vascularization following two basic auditory canal skin incisions.

Three groups of nine patients each were analyzed. The first two groups consisted of those that underwent tympanoplastic due to chronic inflammation of middle ear. Two different standard auditory canal skin incisions were applied, i.e. tympanomeatal flap (TMF) or vascular strip (VS). The third control group consisted of non-operated patients. All the operated patients were subjected to a quantitative analysis of the auditory canal revascularization by means of the Weibel stereological test method, i.e. the B 100 double network system. The density of capillaries, arterioles, venulolymphatic spaces and a total volume density of all vascular elements of the auditory canal skin were measured. The obtained results of vascularization were compared with those of the target control group. It was found out that there were no significant differences in vascularization of auditory canal skin between TMF and VS patients from one side and the control group on the other side.

[A rare case of the high jugular bulb associated with only hearing ear].

The jugular bulb may be present in different positions and dimensions within the temporal bone. In general, high jugular bulbs were classified into 2 types: lateral in which the jugular bulb protrudes into the middle ear and up into the tympanic cavity and medial in which the jugular bulb is abnormally placed more superiorly and medial to the cochlea. We report, a unique case of a high jugular bulb which came round from behind of the internal auditory canal and the cochlea protruding into the posterosuperior part of the mesotympanum. It was a very rare pattern of a high jugular bulb which varies in position. The occurrence of adhesive otitis media caused the high jugular bulb to bleed easily in the only hearing ear. There would be risks of making the patient suffer severe bilateral healing impairment due to only one hearing ear and excessive hemorrhage in surgical treatment. With only one hearing ear, we should therefore select transcatheter interventional angiography when the quantity and frequency of bleeding from the jugular bulb increase so.