We conducted a comparison of 7 typical tracheotomy cannulas (8 mm ID single-tube cannula with a cuff) used in adult patients in Japan and attempted to identify the risk factors in patients with tracheotomy cannula-related complications. The important issues in tracheotomy management are discussed. Comparison of the morphologies of the cannulas revealed that that among the cannulas, the outer diameter differed by a maximum of 0.9 mm, the bending angle differed by a maximum of 20° and the stationary cuff diameter by a maximum of 10 mm. The difference in the curvature radii was 28.8 mm at the maximum, and the difference in the depth from the wing was 29.9 mm at the maximum. To avoid tracheotomy cannula-related complications, we analyzed cases of tracheo-innominate artery fistula, cannula misinsertion in the mediastinum, and tracheoesophageal fistula, which can be fatal. From the viewpoint of the morphology of the cannula, it is desirable to select the a tracheal cannula with an appropriate radius of curvature that would prevent the development of a trachea-innominate artery fistula, with an appropriate depth to prevent its straying into the mediastinum, and with an appropriate outer diameter of the stationary cuff to avoid the development of a tracheoesophageal fistula. Otolaryngologists are the specialists in tracheotomy and are in a position to educate doctors about safe tracheotomy management. It is necessary to understand the characteristics of these cannulas and to avoid complications by proper cannula selection.

　Previously, we studied cochlear compound action potential (CAP) using an equilevel paired click stimulation paradigm in humans with normal hearing. The CAP amplitude in response to the second click of the paired click stimuli was calculated as a ratio of the CAP amplitude in response to the first click. Hereinafter in the text, we use “the second CAP amplitude ratio” to refer to this ratio. The changes in the second CAP amplitude ratio measured as a function of the click intensity levels showed an interesting finding: a sharp decrease at about 60 dB nHL. We call this phenomenon the 60 dB nHL dip. The generation of this 60 dB nHL dip seems to be difficult to explain by conventional auditory nerve adaptation arguments, and other cochlear mechanisms need to be considered. Therefore, in this study, we investigated, using an identical method, the second CAP amplitude ratio in subjects with sensorineural hearing loss and also subjects with normal hearing, for comparative analysis. The ears of the subjects with hearing loss also showed the 60 dB nHL dip, just like the subjects with normal hearing, although it became unclear with progressive deterioration of hearing. Therefore, we supposed that some unknown mechanisms in the cochlea may be responsible for the 60 dB nHL dip. Based on previous auditory-physiology and psychophysiology descriptions, we speculated that the underlying mechanisms could be related to: 1) the functions of different spontaneous discharge rates of single auditory neurons, 2) cochlear compression, and its relation to the growth of non-linearity of the discharge rate of the auditory neurons, and 3)effect of the click sound waveform on the basal membrane movement.

　Deep neck abscess is a serious and potentially life-threatening infection that spreads along the spaces surrounded by the cervical fascia. Because pediatric deep neck abscesses are relatively rare, the clinical characteristics are not yet clearly understood. Surgical treatment remained the first-step approach in most cases of deep neck abscesses in children until recent years. However, numerous recent studies have reported the success of needle aspiration or conservative medical treatment alone.

　Pediatric deep neck abscesses tend to be contained within lymph nodes long before they spread to the fascial planes of the neck; therefore, they are more commonly contained and less extensive than in adults. Many cases of lymphatic abscesses in children can be successfully managed by conservative treatment, without the need for surgery. However, in the case of a peritonsillar abscess or parotid space abscess, surgical treatment may be required because of the different routes of infection. Herein, we report our treatment strategy for pediatric deep neck abscesses according to the site of the abscess.

　We retrospectively examined the data of 11 children with deep neck abscesses seen between September 2016 and March 2019 at our hospital. The most common sites of the abscesses were the retropharyngeal space (n=4), peritonsillar space (n=3), and parotid space (n=2). Of the 11 cases, 7 were managed by conservative treatment alone and 4 were treated surgically. According to the abscess site, all patients with retropharyngeal infection were managed by conservative treatment. Four patients (peritonsillar space: 1, parotid space: 2, posterior cervical space: 1) were treated by needle aspiration as the primary treatment. One of patients with parotid space abscess who failed to improve with antibiotic treatment and needle aspiration was subsequently treated by surgical drainage. No significant complications were observed in any of the patients. According to the abscess site, needle aspiration is an effective alternative procedure to surgical drainage in pediatric cases of deep neck infections.

　The main features of the Utsunomiya method auditory rehabilitation are “full-time hearing aid use from day 1 of rehabilitation with frequent examinations and adjustments for 3 months,” and “the presence of a speech therapist specialized in audiology in charge of hearing aid outpatients.” We established a hearing aid outpatient clinic adopting this method and examined the results over a period of 3 years. Data of a total of 174 subjects who underwent hearing rehabilitation at the hearing aid outpatient clinic of Keiyu Hospital from April 2016 to March 2019 were examined. We investigated the rehabilitation-dropout rate, hearing-aid purchase rate, and accuracy rate of hearing aid fitting by the sound field test and speech intelligibility test.

　The results revealed a rehabilitation-dropout rate of 2.9%, hearing aid purchase rate of 94.8%, and accuracy rate of hearing aid fitting by the sound field test of 97.6%, and by the speech intelligibility test of 94.7%.

　For patients with hearing loss, we found that this method was particularly useful for patients who had difficulties in their daily living due to hearing loss and showed a willingness to improve their hearing.

　Nasal hemangiomas are generally slow-growing tumors. We present the case of a 43-year-old woman with a rapidly growing hemangioma who developed heavy bleeding. She visited a hospital complaining of recurrent episodes of nasal bleeding, and was referred to our hospital 2 weeks later. We detected a tumor in the left nasal cavity which was found to bleed easily, and suspected it as being a hemangioma. Endoscopic surgery was scheduled. The patient developed severe nasal bleeding prior to the surgery, and the tumor volume increased by about 32-fold. Therefore, surgery was performed immediately, after controlling the bleeding by vascular embolization. Histopathology confirmed the diagnosis of hemangioma, with heavy bleeding observed in the resected tumor. Subsequently, we performed histopathological examination of 12 cases of nasal hemangioma and investigated the underlying causes. Nasal hemangiomas that show rapid growth and manifest as nasal bleeding may be associated with bleeding in the histopathological tumor specimen and vascular wall fragility. This type of a nasal hemangiomas should be immediately removed.