We studied noise-induced hearing impairment, including haring loss and tinnitus, aiming to develop a novel therapeutic strategy based on the detailed pathophysiology. First, we found a new noise-related gene, NRF2, polymorphism used by the medical checkup performed in the National Self Defense Force of Japan. We next conducted pathophysiological analysis using a blast-induced hearing loss animal model. As results, we confirmed the synapse degeneration on the inner hair cells after blast exposure, which was consistent with cochlear synaptopathy. By using this model, we could study tinnitus behaviors after blast exposure on rats and the neuroplastic changes in the limbic system were observed on the rats with tinnitus. Now, we are planning to develop a novel therapy for noise-related hearing impairment by using a safe virus vector.
Calcium ion is unique among various ions because it functions not only as a positive charge carrier but also as a key regulator of various cellular reactions. The auditory system also utilizes calcium ion as the key regulator of auditory transmission (i.e., calcium signaling), in the unique mechanisms specialized for sound perception with high fidelity and high dynamic range. Considering its critical role in the inner ear, the mechanisms has a high potential as a target of the novel treatments, desired in the patients with hearing loss or other inner ear symptoms. We need further understanding of the calcium signaling at a molecular level, as it leads to the development of therapeutic drugs targeting calcium signaling in the auditory system.
Canaloplasty is corrective surgery for congenital aural atresia (CAA), and this surgery aims to provide patients with serviceable hearing by restoring the sound-conducting mechanism of the ear and creating a patent, well-epithelialized external auditory canal. The author performed more than 350 cases of canaloplasty until recently and the surgical procedures and outcomes in terms of hearing, sound localization, speech understanding in noise and appearance scale were introduced.
Hearing improved to within 30 dB of air-bone gap in 58% at long-term follow-up. Sound localization ability improved at 6 months and the SSQ questionnaire also showed improvement in spatial domain. Hearing in noise test revealed that signal-to-noise ratio (SNR) improved when the noise comes from the newly-opened atretic ear or from the normal ear as well, which means a restoration of binaural processing. Analysis of an appearance scale shows that canaloplasty has positive aesthetic effects on the appearance of the ear and can effectively reduce related distress. Postoperative stenosis can effectively be prevented by application of a long-term stent.
Canaloplasty is a safe, effective method for restoring hearing and binaural advantages, and should be considered as a first management option for patients with CAA.
Cochlear implantation is an effective procedure for auditory rehabilitation of patients with severe to profound deafness. However, surgical insertion of the electrode induces various histological changes within the cochlea. Immediate changes include insertional trauma to the cochlea. Delayed changes include a tissue response consisting of inflammation, fibrosis and neo-osteogenesis induced by trauma and an immunologic reaction to a foreign body.
First, the effect of these delayed changes on the word recognition scores achieved post-operatively was evaluated in this study using 3-D reconstruction software. The postoperative CNC word score was negatively correlated with the % volume of new bone within the scala tympani, scala media/vestibuli and the cochlea, but not with the % volume of fibrous tissue. The % volume of new bone in the scala media/vestibuli was positively correlated with the degree of intracochlear insertional trauma, especially trauma to the basilar membrane.
Next, the degree of preservation of hair cells, supporting cells, and innervating dendritic processes after cochlear implantation in the human using immunohistochemical methods was evaluated. Two sections including the modiolus or basal turn from each temporal bone were stained using three antibodies in both implanted and unimplanted ears. Insertion of a cochlear implant electrode may significantly affect the inner and outer hair cells both along and apical to the electrode, and dendritic processes in the osseous spiral lamina along the electrode. There was less effect on the pillar cells, Deiters’ cells, and spiral bundles. Preservation of the inner and outer pillar cells and Deiters’ cells, possible candidates for hair cell regeneration, was similar in the implanted and unimplanted cochlea, and therefore it may be possible to regenerate hair cells in the implanted as well as in unimplanted cochleae in the future.
According to our survey of cochlear implants (CI) in Japan, the number of pediatric CI increases and the number of bilateral CI (BCI) also tends to increase. BCI has better results than First CI (FCI), e.g. speech discrimination and intelligibility were improved not only in the silence but also under the noise. Many research articles also report in improvements of directionality, and hearing ability on the second CI side, tinnitus improvement, and so on. Meanwhile, a number of researchers have become more aware of single-sided deafness (SSD) in recent years throughout the world. Some foreign governments, excluding Japan so far, allowed CI for SSD because of its. Here, our study reports the effect of BCI in children, such as binaural hearing and the regular school enrollment rate (82/100 = 82%).
Our study compares the mean speech discrimination score using various tests with the 2nd CI and BCI according to the time interval between FCI and 2nd CI. Thus we can determine the critical interval time period between FCI and 2nd CI statistically. Finally discussed how to proceed with patients, considering simultaneous or sequential CI and provides the information for the future of BCI and binaural hearing.
Imaging-based diagnosis of sudden sensorineural hearing loss or Ménière’s disease using magnetic resonance imaging (MRI) has made great progress in recent years. In sudden deafness, high signal in the inner ear is associated with hearing prognosis. In addition, the significance of endolymphatic hydrops in Meniere’s disease and endolymphatic hydrops-related diseases is gradually becoming clear. MRI may be indispensable for the diagnosis and treatment of inner ear diseases due to further advancements of imaging technology in the future.
Congenital aural atresia (CAA) usually results in conductive hearing loss with a maximum air-bone gap. Bone-conductive hearing aid and canalplasty are used in order to improve conductive hearing loss with CAA. Vibrant Soundbridge (VSB) and bone conductive implant (Baha, Bonebridge) have been recently considered as new methods for improving hearing loss with CAA. VSB gets an advantage in respect of sound quality compared to Baha and Bonebridge. There are several surgical techniques in VSB vibroplasty to the patients with CAA. In cases of post-canalplasty, putting the FMT to stapes or round window (RW) membrane is selected. VSB placement to RW via the retrofacial approach can be sometimes chosen because of dislocation of the facial nerve. Placement of FMT with clip-coupler to the stapes may be first choice in the patients with pre-canalplasty. If these surgical techniques are difficult, bone conductive implantation can be feasible alternatively.
Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis affecting small-sized vessels of the lungs and nervous system. However, otologic presentations are often dominant early in the course of EGPA, making it difficult to differentiate EGPA from eosinophilic otitis media (EOM). Here we demonstrate a case of EGPA showing otitis media as the major symptom, and statistically compare clinical profiles of EGPA and EOM. Results revealed that the most typical otologic manifestation of EGPA is chronic otitis with granulating inflammation mainly affecting the posterior part of the meatus and ear drum. Gadolinium-enhanced 3D fast spoiled gradient-recalled imaging indicated the presence of posterior auricular arteritis as a potential etiology of granulomatous otitis of EGPA. However, vestibular examinations, including vestibular evoked myogenic potential, indicated the involvement of other vessels in the inner ear. Unlike EOM, peripheral neuropathy, facial nerve paresis and eosinophilia were specific to EGPA.
Transcanal endoscopic stapes surgery has many benefits, including good visualization of the stapes and easy access to it, and less invasiveness when compared to microscopic ear surgery. We investigated the postoperative outcomes of patients who underwent endoscopic stapes surgery. This study examined 25 patients who underwent endoscopic stapes surgery at the Department of Otolaryngology, Head and Neck Surgery, Yamagata University Faculty of Medicine between January 2012 and December 2016. The Fisch’s reversal steps stapedotomy was performed via transcanal endoscopic ear surgery (TEES) in all patients. Twenty-one patients were treated for otosclerosis, 2 for stapes fixation due to chronic otitis media, and 2 for stapes malformation. The mean age of the patients was 51.0 years (18–79 years) and the mean follow-up duration was 22 months (12–60 months). Pure tone audiometry was carried out for all patients pre- and postoperatively. Air conduction and bone conduction thresholds were measured at frequencies of 500, 1000, and 2000 Hz, in accordance with the criteria of the Japan Otological Society (JOS) (2010), and at frequencies of 500, 1000, 2000, and 3000 Hz (average of 2000 and 4000 Hz) in accordance with the criteria of the American Academy of Otolaryngology, Head and Neck Surgery (AAO-HNS). Postoperative complications were investigated retrospectively based on medical records. Hearing improved postoperatively in all 25 (100%) patients, based on the JOS criteria, and the postoperative air-bone gap closed down to less than 10 dB in 22 (88.0%) patients, which is considered successful according to the AAO-HNS criteria. Complications included vertigo in 4 patients (16.0%), tinnitus in 3 patients (12.0%), and dysgeusia in 2 patients (8.0%), despite no incidence of intraoperative severing of the chorda tympani. In contrast, no patients experienced sensorineural hearing loss or facial nerve palsy. Our retrospective analysis thus revealed that TEES can be safely employed in stapes surgery to successfully treat an array of conditions.
We report a case of multiple congenital cholesteatomas. A 7-year-old girl presented with suggested right-ear hearing loss during a medical checkup in her elementary school. On examination, a white lesion was observed through the intact eardrum. A two-staged operation was performed. The initial procedure revealed 11 cholesteatomas between the posterior tympanum and the mastoid. Two residual cholesteatomas were extracted and a tympanoplasty type IVc performed during the second-look procedure. The post-operative condition of the eardrum was satisfactory; however, long-term follow-up is required.
The patient was an 86-year old woman with diabetes mellitus, who presented with severe otorrhea and otalgia of the right ear after receiving treatment for 70 days at another clinic. Multidrug-resistant Pseudomonas aeruginosa (MDRP) and methicillin-resistant Staphylococcus aureus (MRSA) were detected in the otorrhea. She was referred to our hospital and administered antibiotic treatment under the diagnosis of malignant external otitis; the otorrhea was positive for only MDRP at our hospital, but antibiotic treatment was administered for MRSA as well as MDRP. In addition, surgery was performed to enable drainage and discriminate possible malignant tumors. During the treatment course, antibiotic treatment with vancomycin was changed due to the development of vancomycin-induced kidney injury; finally, after treatment at our hospital for 75 days, and follow-up outpatient treatment for 20 days, the patients’ symptoms, laboratory data, and imaging findings were improved. No recurrence was observed at follow-up of at least 1 year. This case report highlights that it is important to conduct biochemical tests including that of kidney function and therapeutic drug monitoring due to the potential of vancomycin to cause kidney injury even at a blood level of within treatment range.
Damage to the stapes due to an earpick injury results in irreversible sensorineural hearing loss, and prompt treatment is required. Based on earlier reports, emergency surgery is rarely performed on the day of the injury. We describe the case of a 12-year-old boy injured by an earpick who underwent same-day emergency surgery, and whose hearing ability was relatively preserved. He visited our department approximately 3 hours after the injury, and an emergency surgery was performed approximately 6 hours after the injury. During the procedure, a piece of the earpick stick was found in the tympanic cavity and removed. The stapes was fractured, the oval window was open, and air was found in the inner ear cavity. The air was replaced with saline, and the oval window was closed with temporal fascia. The sound conduction pathway was reconstructed by inserting the reformed incus between the fascia and eardrum. The postoperative bone conduction hearing ability was relatively better conserved than in earlier reports. Therefore, this report suggests that early surgical treatment leads to conservation of hearing even in cases where the stapes is damaged.
The foramen of Huschke is a bony defect on the medial side of the anterior wall of the external auditory canal. It requires treatment when any symptom or condition occurs, such as temporomandibular joint herniation into the external auditory canal, tinnitus, otalgia, and salivary otorrhea. I herein report a rare case of temporomandibular joint herniation into the external auditory canal through the foramen of Huschke that required reconstructive surgery.
A 74-year-old man with right-sided otalgia and otorrhea was referred to our department during his admission due to cerebral infarction. The anterior wall of the right external auditory canal near the tympanic membrane was swollen and purulent otorrhea was seen. X-ray computed tomography showed a bony defect of the posterior wall of the right glenoid fossa. Even after intravenous antibacterial therapy, mucinous discharge suggestive of mandibular joint synovial fluid because of its high concentration of hyaluronic acid persisted. The discharge stopped spontaneously at 117 days, but the patient hoped to have reconstructive surgery of the external auditory canal to obtain relief from the noises generated by the opening and closing of the mouth.
The surgery was performed using an extended endaural approach under general anesthesia. An endaural incision was made behind the edge of tragus, extending down to the level of the floor of the external auditory meatus. While dissecting the external auditory canal skin from the bone, the area of bony defect was apparent. From the cartilagenous-bony junction of the anterior external auditory canal wall, the dissection of the periosteum towards the glenoid fossa was performed under endoscopic viewing. The full thickness cartilage harvested from the tragus was inserted into the area of the defect from the glenoid fossa. The temporalis fascia and connective tissue were also inserted between the canal skin and inserted cartilage.
Two weeks after the operation, ear packing was removed. The patient was recommended to eat only soft foods for two months. The use of an oral splint during sleep was started immediately after the operation to weaken the effect of bruxism. Eleven months after the operation, the patient was satisfied with the reduced noise generated by opening and closing the mouth.
This approach was excellent cosmetically, and the use of the endoscope was useful for not only observing the glenoid fossa in detail but also inserting the large cartilage graft in the appropriate position with minimal damage.