Outer Ear Canal Research Articles

Tympanic membrane perforation, otitis media and labyrinthitis caused by otomycosis confirmed by intravenous gadolinium 1.5 tesla MRI-a case report

Otomycosis is a fungal ear infection, mostly a superficial mycotic infection of the outer ear canal. The infection may be either subacute or acute but chronic form is around 10%. The characteristic of otomycosis are discharge, pruritus, or more severe discomfort. Here we report a 46-year-old Asian woman presented with vertigo and was diagnosed as otomycosis with the complications of tympanic membrane perforation, otitis media and labyrinthitis of inner ear which was confirmed by IV-Gd 1.5 T MRI. This case is a chronic otomycosis related to cerumen removal two year before this onset. Our study supported the suggestion that otomycosis should include fungal infections of the middle and inner ear, furthermore the infection of the inner ear may be included as labyrinthitis with the symptom of vertigo.

A Rare Cause of Facial Paralysis in Children: A Case of Ramsay Hunt Syndrome

AbstractPeripheral facial paralysis in children can have many causes including trauma, otitis media, head and neck tumors, congenital anomalies, viral infections, as well as metabolic and genetic factors. One cause of peripheral facial paralysis is Ramsay Hunt syndrome (RHS), which is also known as herpes zoster oticus, affecting the seventh and eighth cranial nerves. It is characterized by inner ear dysfunction, periauricular pain, and peripheral facial paralysis accompanied by the presence of an erythematous vesicular rash around the ear pinna and outer ear canal or in the oral mucosa. RHS is very rare in children when compared with its prevalence in adults. A 13-year-old male with no prior medical history applied to the pediatric emergency department after having first developed a vesicular rash on the left ear pinna and pain around the left ear, which was followed 1 day later by the development of ipsilateral facial asymmetry. The patient was hospitalized and simultaneously started on 2 mg/kg/d methylprednisolone for 10 days (followed by a 15-day taper), 100 mg/kg/d intravenous ceftriaxone twice per day (stopped on day 10), 30 mg/kg/d intravenous acyclovir three times per day (stopped on day 21), ciprofloxacin ear drops, tobramycin eye drops, ointment, and artificial tear drops with eye patching. However, only a minimal improvement was observed in the patient's peripheral facial paralysis by day 21. When compared with the prevalence in adults, RHS is very rare in children, which is why reports of pediatric RHS are limited in the literature. Therefore, additional studies are needed to provide information about the pathophysiology, diagnosis, and treatment of pediatric RHS.

Diagnosis and treatment of external otitis

External otitis is one of the most common infections in the head and neck region, as about 10% of all people suffer from it at least once during their life. It is an infection of the cutis and subcutis of the outer ear canal caused by bacteria, viruses, and fungus as well as allergens or degenerative toxic substances. Aconcomitant infection of the eardrum (myringitis) may develop. Patients typically present with unilateral, rarely bilateral, earache (otalgia), with accompanying hearing loss and sometimes discharge from the ear (otorrhea). In general, otalgia is one of the most common reasons for consulting ageneral practitioner in Germany (4.2-7.7%), especially for children up to 14years.

An intracochlear DP-gram: Proof of principle in noise-damaged rabbits

Distortion-product otoacoustic emissions (DPOAEs) can be used to assess cochlear damage and are often evaluated by generating a DP-gram in which 2f1-f2 DPOAE levels are plotted as a function of the higher-frequency primary at f2. DPOAEs are derived from the reverse propagation of distortion-product (DP) wavelets from their intracochlear sites of generation to emerge as measurable acoustic signals in the outer ear canal. However, at least, some of these same wavelets also propagate within the cochlea in the normal forward direction to the DP-frequency (fdp) place, where they appear as intracochlear distortion products (iDPs). Depending on several factors, especially, the extent to which DP wavelets add or cancel with each other in phase, one might expect iDPs to differ from DPOAEs in their ability to map the frequency pattern of cochlear damage. In the present study, the behavior of 2f1-f2 iDPs was inferred by interacting a probe tone (f3) with the iDP of interest to produce a ‘secondary’ DPOAE (i.e., DPOAE2ry), which was then used to infer the level of 2f1-f2 iDPs as a function of the f2-test frequency, thus, constituting a newly developed iDP-gram. To determine the feasibility of and potential applications for the iDP-gram procedure, noise-induced cochlear damage was assessed in two ‘test’ rabbits, one of which exhibited a well-defined punctate loss in their DP-gram, while the other exhibited a broader V-shaped loss. To validate the iDP-gram procedure, standard DP-grams were simultaneously collected and compared to their iDP-gram counterparts. Cochlear damage was independently assessed using auditory brainstem responses (ABRs) describing threshold-shift patterns to which both DP-gram types could be compared. Each DP-gram variety, to some extent, was able to detect a punctate loss in one rabbit and a broader V-shaped loss in the other. For the punctate-loss subject, the standard DP-gram showed a more generalized loss across test frequencies, while iDP-grams showed several localized notches superimposed on the generalized-loss pattern. In general, for the V-shaped loss pattern, both DP-gram types performed very well at detecting the large loss, with the lower primary-tone levels being most sensitive. At the narrow primary-tone ratios of f2/f1=1.05, standard DP-grams were unable to detect either loss pattern, while for the punctate loss, they paradoxically showed enhancement. Notably, the simultaneously collected iDP-grams performed favorably at the narrow-ratio setting, which is consistent with the notion that DPs travelling toward the 2f1-f2 fdp place are not subject to the cancellation of wavelets typical for narrow primary-ratio conditions that can confound measures of DPs moving towards the ear canal to emerge as DPOAEs.

Usage of glass ionomer cements for reconstructions in the head region

Glass ionomer cements are a two-component hybrid material, consisting of inorganic glass particles, surrounded by an insoluble hydrogel matrix. They are a group of materials based on the acid/ base reaction between poly (alkenoic) acid and an ion-leachable silicate glass. Their biocompatibility, osteoconductive behavior, and ability to bond to bone and metals have generated interest in the material for medical applications. GIC are widely used in dental medicine as an obturation material in primary teeth for treatment and prophylaxis of dental caries, because they have the ability to create a physicochemical bond to tooth structure and to release fluoride. They are currently frequently used in otological and neuro-otological surgery. Apart from ossicular chain reconstruction, they are used for repair of tegmen defects, outer ear canal reconstruction, mastoid obli teration, and stabilization of some hearing prostheses.

Self-demodulation characteristics of amplitude-modulated bone-conducted ultrasound in the human body presented to the neck, trunk and arm

Bone-conducted ultrasound (BCU) can be clearly perceived and can transmit speech information using amplitude-modulation (AM). BCU can also be perceived when presented to body parts like the neck, trunk and arms. When AM-BCUs propagate in the biological tissues with nonlinearity, like the cartilage, modulator signals may be self-demodulated. This demodulated-sound may affect BCU hearing. To examine the availability of the demodulated-components, difference limens for frequency (DLFs) were measured with/without the low-pass-masking noises that masked the demodulated-components. Practical frequency-discrimination ability was obtained even at distant body parts, whereas DLFs increased when the demodulation components were masked. Additionally, to elucidate the demodulation mechanisms in the human body, vibrations were measured around the cartilage. Significant demodulated-components were generated at especially the cartilage near the outer ear canal. These results indicated the availability of demodulated-components to improve hearing of the distantly-presented BCU, and provide useful information to optimize the novel BCU devices.

Evaluation of hearing function in patients with lichen planus

Lichen planus (LP) is a chronic, autoimmune, inflammatory disease. We believe that tympanic membrane and outer ear canal can be affected by the disease and since it is an autoimmune disease inner ear involvement may be seen. The aim of this study was to evaluate hearing functions in patients with LP. Thirty patients with LP and 28 healthy controls were involved in the study. Pure tone audiometry, tympanogram and Transient Evoked Otoacoustic Emissions tests were applied to the patients. When the airway hearing thresholds of the patient and control groups in the 125–8000 Hz frequency range were compared, statistically significant differences were found at 4000, 6000 and 8000 Hz frequencies in the right ear and at 125, 4000, 6000 and 8000 Hz frequencies in the left ear. In the LP patient group, 6 patients had sensorineural hearing loss, 3 patients had conductive hearing loss, and 2 patients had mixed hearing loss. Of the 3 patients with conductive hearing loss, 2 had cutaneous and 1 had both mucosal and cutaneous involvement. Of the patients with mixed hearing loss, 1 had cutaneous and 1 had both mucosal and cutaneous involvement. In patients with sensorineural hearing loss, 1 had mucosal, 3 had cutaneous, and 2 had both mucosal and cutaneous involvement. Sensorineural, conductive or mixed hearing loss can be observed in LP patients.

Cutaneous lesions of the auricular portion of external ear

Aim: Diseases coming from the external ear (outer ear canal and auricle) skin can be evaluated by many medical disciplines. External ear cutaneous lesions can be nonneoplastic, preneoplastic or neoplastic. Our aim in this study is to evaluate these surgically treated diseases.Material and Methods: All external ear tumors and tumor-like lesions that were surgically excised between 2013 and 2018 were evaluated retrospectively. The relationship between demographic features and histopathological findings and prognostic factors were analyzed.Results: Lesions were excised in the external ear in a total of 141 patients. While 91 (64.5%) of the cases were male and 50 (35.5%) were female, the average age was 33.9 (between 1 and 98 years old). While the average age of all benign tumors and non-neoplastic lesions was 27.7, 60.5% were male and 39.5% were female. The average age of malignant tumors and precursors was 67.2, the male rate was 86.4%, and the female rate was 13.6%. While cystic lesions are the most common lesion group with 27.7% (39 cases), benign non-epithelial tumors 27% (38 cases); malign epithelial tumors 15.6% (22 cases); hamartomas and similar lesions 11.3% (16 cases); inflammatory and infectious conditions 7.8% (11 cases); other formations (cutaneous deposit etc.) 7.8% (11 cases), and benign epithelial tumors 2.8% (4 cases), respectively. The most common cystic lesion was epidermal cyst and the most common benign and non-epithelial lesions were intradermal melanocytic nevi and keloid. Malignant epithelial tumors mostly detected in the external ear, squamous cell carcinoma and basal cell carcinoma. Among the hamartoma or congenital lesions and inflammatory lesions, accessory tragus and hair follicular nevus and foreign body granulomatous reaction were the most frequently observed, respectively.Among benignepithelial tumors, seborrheic keratosis was the most common.Conclusion: There are rare cutaneous lesions of the external ear that are treated with various medical and surgical specialities. In this anatomical location, tumors seen at a young age are mostly benign, while malignant tumors are more common in older ages and males, while hamartoma and similar congenital lesions are observed at a young age. A multidisciplinary approach in treatment is important both in terms of prognosis and aesthetics.

Giant Epidermoid Cyst of the Bony External Ear Canal - A Rare Case Report

We describe a case of epidermoid cyst of the external ear canal. Although the outer ear canal was almost filled by the cyst, no bone erosion was observed. Dimensions of epidermoid cyst was 13 × 10 mm. According to our knowledge, this case is the biggest epidermoid cyst of the bony external ear canal in the literature.

Evaluation of Pulse Arrival Times during Lower Body Negative Pressure Test for the Non-Invasive Detection of Hypovolemia.

The early detection of occult bleeding is a difficult problem for clinicians because physiological variables such as heart rate and blood pressure that are measured with standard patient monitoring equipment are insensitive to blood loss. In this study, the pulse arrival time (PAT) was investigated as an easily recorded, non-invasive indicator of hypovolemia. A lower body negative pressure (LBNP) study with a stepwise increase of negative pressure was conducted to induce central hypovolemia in a study population of 30 subjects. PAT values were extracted from simultaneous recordings of the electrocardiogram (ECG) and photoplethysmographic (PPG) recordings both from the index finger and from within the outer ear canal. Stroke volume (SV) was recorded as a reference measure by transthoracic echocardiography. An inter- and intra-individual correlation analysis between changes in SV and the PAT measurements was performed. Furthermore, it was assessed if PAT measurements can indicate a diminished SV in this scenario. It could be demonstrated that the measured PAT values are significantly increased at the lowest LBNP pressure level. A very strong intra-individual correlation (ρ ≥ 0.8) and a moderate inter-individual correlation (ρ ≥ 0.5) between PAT and SV measurements were found. Thus, PAT measurements could be a viable tool to monitor patient specific volemic trends. Further research is needed to investigate if PAT information can be utilized for a more robust inter-subject quantification of the degree of hypovolemia.

Comparison of Otoacoustic Emissions in Asymptomatic Diabetes Mellitus and Normal Hearing Control Groups

Background: Diabetes mellitus (DM) is a chronic metabolic disorder. Previous studies reported the hearing impairment of diabetes patients as a progressive bilateral symmetrical sensorineural hearing loss (SNHL) of gradual onset which predominantly affected the higher frequencies, and found that diabetic patients had unsatisfactory hearing thresholds than nondiabetics in the same age group. For the use of evoked otoacoustic emissions (EOAEs) as a clinical test of hearing, EOAEs are sound which can be recorded in the outer ear canal and give objective information about preneural, mechanical elements of the cochlear function.
 Objective: To compare the otoacoustic emissions of asymptomatic DM patients with a normal hearing control group.
 Methods: All subjects received a routine audiologic evaluation which consisted of pure-tone air-bone conduction tests, tympanograms, and stapedius acoustic reflex tests. OAEs were measured in 30 asymptomatic diabetic patients with a mean age of 55.73 years and an age-matched 30 subjects normal hearing control group with a mean age of 50.87 years.
 Results: The pure-tone thresholds at 3, 4, 6, and 8 kHz; transient-evoked otoacoustic emissions (TEOAEs) amplitudes at 1, 1.5, 2, and 3 kHz; and the distortion product otoacoustic emissions (DPOAEs) amplitudes at 1, 1.5, 2, 3, 4, and 6 kHz were significantly different (P < .05) between the asymptomatic and control groups.
 Conclusions: This study suggested that diabetic patients had a significant hearing impairment. SNHL is gradually progressive and is a common condition in DM patients and their thresholds for hearing are higher at higher frequencies.

Feasibility of High-Resolution Computed Tomography Imaging for Obtaining Ear Impressions for Hearing Aid Fitting.

This study investigated the feasibility of obtaining ear impressions for hearing aids by using 3-dimensional high-resolution computed tomography (HRCT) images. Case series. One referral tertiary center. Hearing-impaired adults who were fitted with 1 or 2 behind-the-ear hearing aid(s) and had undergone temporal bone HRCT for various ear pathologies were enrolled in this study. Earmolds were fabricated from the impressions obtained using the conventional ear canal silicone injection technique and the HRCT reconstructed technique. Outer ear canal resonance frequencies and amplitude in open ears and those measured with silicon and HRCT reconstructed earmolds were determined through real-ear gain measurements, including real-ear unaided gain (REUG) and real-ear occluded gain (REOG), for comparison. A total of 50 HRCT reconstructed earmolds were compared with 50 conventional silicon injection earmolds. The average value of open ear canal resonance amplitude (REUG) for each ear was 0.41 to 16.76 dB. No statistically significant difference in resonance amplitude (REOG) was observed between silicon and reconstructed earmolds (paired t test, P > .05). The mean insertion loss (REOG-REUG) at all frequencies also did not differ significantly between the two earmolds (paired t test, P > .05). According to our real-ear measurements, acoustic characteristics of the HRCT reconstructed earmolds were compatible with those of the silicone injection earmolds. Despite concerns about increased cost and radiation exposure, the HRCT reconstructed technique is a clinically useful and applicable method and can reduce potential safety complications for difficult cases.

Otolaryngological foreign bodies in a tertiary medical center in Turkey: A comparison of pediatric and adult patients

Aim: The aim of the present research was to report on the characteristics of ear, nose, and throat foreign bodies in patients admitted to a tertiary medical center in Turkey and to analyze the extraction procedure, results, and complications. Material and Methods: A retrospective study conducted between August 2015 and May 2019 included 1042 patients referred to the emergency and otolaryngology department with ear, nose, and throat foreign bodies. The pediatric group included 612 cases, while the adult group included 430 cases. Sex, the type of foreign bodies, symptoms, extraction method, and complications were analyzed. Results: The most common foreign bodies were hard round objects frequently found in front of the middle turbine in the nose of children, while pieces of cotton buds were found in the outer ear canal in adults. In the pediatric group, the distribution of foreign bodies was 53.43% in boys and 46.57% in girls. Furthermore, the intervention was performed in three children (0.49%) admitted to the emergency department because of the organic foreign body escaping to the throat, as a result of which foreign bodies were removed. However, the prognosis for these patients was poor: a neurological sequela in one patient, death in two patients. In the adult group, the distribution of foreign bodies was 49.76% in males and 50.24% in females. No fatal cases were observed in this group. The ratio of foreign bodies removed under general anesthesia in the pediatric group was 3.43%, while it was 0.23% in the adult group, and the difference between them was statistically significant (p = 0.018). No statistical difference was observed between the groups with regard to complication rates (p>0.05). Conclusion: Otolaryngological foreign bodies are usually harmless, but they can cause infections and minor complications when they are overlooked or there is prolonged exposure, and these objects in the throat may be fatal, especially in children.

Effects of tympanic membrane perforation on middle ear transmission in gerbil

Perforations of the tympanic membrane (TM) alter its structural and mechanical properties, thus resulting in a deterioration of sound transmission through the middle ear (ME), which presents itself clinically as a conductive hearing loss (CHL). The resulting CHL is proposed to be due to the loss of the pressure difference across the TM between the outer ear canal space and the ME cavity, a hypothesis which has been tested with both theoretical and experimental approaches. In the past, direct experimental observations had been either from the ME input (umbo) or the output of the stapes, and were focused mainly on the low frequency region. However, there was little documentation providing a thorough picture of the influence of systematically increasing sizes of TM perforations on ME sound transmission from the input (i.e., pressure at the TM or motion of the umbo) to the output (pressure produced by the motion of the stapes). Our study explored ME transmission in gerbil under conditions of a normal, intact TM followed by the placement of mechanically-induced TM perforations ranging from miniscule to complete removal of the pars tensa, leaving the other parts of ME intact. Testing up to 50 kHz, variations of ME transmission were characterized in simultaneously measured tone induced pressure responses at the TM (PTM), pressure responses in the scala vestibuli next to the stapes (PSV), and velocity measurements of the umbo (Vumbo), as well as by detailed descriptions of sound transmission from the TM to the stapes, i.e., the umbo transfer function (TF), the transfer of the sound stimulus along the ossicular chain as found from the ratio of cochlear pressure to umbo motion, and ME pressure gain (MEPG). Our results suggested that increasing the size of TM perforations led to a reduction in MEPG, which appeared to be primarily due to the reduction in the effective/initial mechanical drive to the umbo, with a relatively smaller decrease of sound transfer along the ossicular chain. Expansion of the perforation more than 25% appeared to drastically reduce sound transmission through the ME, especially for the higher frequencies.

Magnetic Resonance Imaging Artifacts and Cochlear Implant Positioning at 1.5 T In Vivo.

Objective Cerebral magnetic resonance imaging with the magnet of the cochlear implant receiver/stimulator in place causes artifacts and hinders evaluation of intracerebral structures. The aim of this study was to evaluate the internal auditory canal and the labyrinth in a 1.5T MRI with the magnet in place. Study Design Observational study. Setting Tertiary referral center. Subjects and Methods The receiver/stimulator unit was placed and fixed onto the head of three volunteers at three different angles to the nasion–outer ear canal (90°–160°) and at three different distances from the outer ear canal (5–9 cm). T1 and T2 weighted sequences were conducted for each position. Results Excellent visibility of the internal auditory canal and the labyrinth was seen in the T2 weighted sequences with 9 cm between the magnet and the outer ear canal at every nasion–outer ear canal angle. T1 sequences showed poorer visibility of the internal auditory canal and the labyrinth. Conclusion Aftercare and visibility of intracerebral structures after cochlear implantation is becoming more important as cochlear implant indications are widened worldwide. With a distance of at least 9 cm from the outer ear canal the artifact induced by the magnet allows evaluation of the labyrinth and the internal auditory canal.

The Molecular Identification and Antifungal Susceptibilities of Aspergillus Species Causing Otomycosis in Tochigi, Japan

Aspergillus species are the most common pathogenic fungi involved in otomycosis, an infection of the outer ear canal. In this study, we examined the incidence of Aspergillus infections and the antifungal susceptibilities of 30 Aspergillus species isolates from patients with otomycosis who visited Saiseikai Utsunomiya Hospital between August 2013 and July 2016. Based on the morphological test results, the strains were identified as Aspergillus niger sensu lato (20 strains), A. terreus sensu lato (7 strains), and A. fumigatus sensu lato (3 strains). In contrast, the molecular identifications based on analyzing the isolates' partial β-tubulin gene sequences revealed them to be A. niger sensu stricto (12 strains), A. tubingensis (8 strains), A. terreus sensu stricto (7 strains), and A. fumigatus sensu stricto (3 strains). The antifungal susceptibility test results indicated that strains of A. tubingensis and A. niger sensu stricto displayed lower susceptibilities to ravuconazole, compared with the other isolates. The Aspergillus strains from this study showed low minimum inhibitory concentrations toward the azole-based drugs efinaconazole, lanoconazole, and luliconazole. Therefore, these topical therapeutic agents may be effective for the treatment of otomycosis.

Bipolar disorder in the balance.

Bipolar disorder (BD) is a severe mood disorder that lacks established electrophysiological, neuroimaging or biological markers to assist with both diagnosis and monitoring disease severity. This study's aim is to describe the potential of new neurophysiological features assistive in BD diagnosis and severity measurement utilizing the recording of electrical activity from the outer ear canal called Electrovestibulography (EVestG). From EVestG data sensory vestibulo-acoustic features were extracted from a single supine-vertical translation stimulus to distinguish 50 depressed and partly remitted/remitted bipolar disorder patients [18 symptomatic (BD-S, MADRS > 19), 32 reduced symptomatic (BD-R, MADRS ≤ 19)] and 31 age and gender matched healthy individuals (controls). Six features were extracted from the measured firing pattern interval histogram and the extracted shape of the average field potential response. Five of the six features had low but significant correlations (p < 0.05) with the MADRS assessment. Using leave-one-out-cross-validation, unbiased parametric and non-parametric classification routines resulted in 75-79%, 84-86%, 76-85% and 79-82% accuracy for separation of control from BD, BD-S and BD-R as well as BD-S from BD-R groups, respectively. The main limitation of this study was the inability to fully disentangle the impact of prescribed medication from the responses recorded. A mix of stationary and movement evoked EVestG features produced good discrimination between control and BD patients whether BD-S or BD-R. Moreover, BD-S and BD-R appear to have measurably different pathophysiological manifestations. The firing pattern features used were dissimilar to those observed in a prior major depressive disorder study.

The Impact of Two-Stage Subtotal Petrosectomy and Round Window Vibroplasty on Bone Conduction Thresholds

Objective: To evaluate possible increases in bone conduction (BC) hearing thresholds in patients undergoing subtotal petrosectomy (SP) with fat obliteration and blind sac closure of the outer ear canal and subsequent round window vibroplasty. Patients and Interventions: Between 1997 and 2013, 43 patients (45 ears) with combined hearing loss and recurrent chronic otitis or status post formation of a radical cavity underwent SP around 6 months prior to implantation of a Vibrant Soundbridge^TM. Pure tone audiograms (0.5, 1, 1.5, 2, 3, 4, and 6 kHz) prior to SP, after SP, prior to implantation, after implantation, and at first fitting around 5 weeks after implantation were collected and statistically analyzed. Results: The comparison between BC thresholds before SP and at first fitting showed an overall decline during the two-step procedure between 2.8 and 6 dB that was significant (p < 0.05, Student t test) at 2, 3, 4, and 6 kHz. Conclusion: In some cases, SP is the only way to eradicate chronic otitis and to achieve a suitable environment for the implantation of active middle ear implants. The present data demonstrate a relatively small but significant decline in BC thresholds throughout the whole procedure. Knowledge of its extent is mandatory for a correct indication for later implantation of a Vibrant Soundbridge^TM.

3D fiber deposited polymeric scaffolds for external auditory canal wall.

The external auditory canal (EAC) is an osseocartilaginous structure extending from the auricle to the eardrum, which can be affected by congenital, inflammatory, and neoplastic diseases, thus reconstructive materials are needed. Current biomaterial-based approaches for the surgical reconstruction of EAC posterior wall still suffer from resorption (biological) and extrusion (synthetic). In this study, 3D fiber deposited scaffolds based on poly(ethylene oxide terephthalate)/poly(butylene terephthalate) were designed and fabricated to replace the EAC wall. Fiber diameter and scaffold porosity were optimized, leading to 200 ± 33 µm and 55% ± 5%, respectively. The mechanical properties were evaluated, resulting in a Young's modulus of 25.1 ± 7.0 MPa. Finally, the EAC scaffolds were tested in vitro with osteo-differentiated human mesenchymal stromal cells (hMSCs) with different seeding methods to produce homogeneously colonized replacements of interest for otologic surgery. This study demonstrated the fabrication feasibility of EAC wall scaffolds aimed to match several important requirements for biomaterial application to the ear under the Tissue Engineering paradigm, including shape, porosity, surface area, mechanical properties and favorable in vitro interaction with osteoinduced hMSCs. This study demonstrated the fabrication feasibility of outer ear canal wall scaffolds via additive manufacturing. Aimed to match several important requirements for biomaterial application to ear replacements under the Tissue Engineering paradigm, including shape, porosity and pore size, surface area, mechanical properties and favorable in vitro interaction with osteo-differentiated mesenchymal stromal cells.

Evaluation of the Antimicrobial Effects of Nano-Essences of Allium sativum L., Thymus vulgaris L., Mentha piperita L., and Chamaemelum nobile L. on Common Causes of Otitis Externa

Background: Inflammation or infection of the ear that refers to as otitis is a common ear disorder. The otitis externa infection involves outer ear and ear canal. Streptococcus pyogenes, Staphylococcus aureus, and Pseudomonas aeruginosa can be pointed out as the common causative agents of this infection. Due to the detrimental effects of chemical drugs on humans, utilizing the new formulation of herbal essential oils, such as nano-encapsulation is considered owing to the more efficient and reduction of adverse effects resulting from the direct application of essential oils. In this in vitro study, the antimicrobial effects of 4 nano-essences were compared to pure essential oils against four major microorganisms involved in otitis externa (namely, S. pyogenes, S. aureus and P. aeruginosa). Methods: To evaluate the antibacterial effects of nano-essences, minimum inhibitory concentration (MIC) quantitative determination and minimum bactericidal concentration (MBC) were first carried out, and then qualitative disk diffusion tests were conducted. Results: The MIC quantitative test results demonstrated that among the evaluated essential oils, garlic nanoessence had the most antimicrobial effect at the lowest concentration. Besides, the results showed that nanoessences had lower effect compared to pure essential oils. Diffusion disc test results revealed that nano-essences could not be released from paper discs diffusion in solid media. Conclusions: Results suggested great antibacterial effects of nano-essences of garlic, thyme, peppermint, and chamomile on 3 strains of bacteria involved in otitis externa and it can be promised to produce new drugs, with lower side effects in eliminating these pathogens.