Yusuke Takata

Auditory evoked magnetic fields in patients with absent brainstem responses due to auditory neuropathy with optic atrophy.

OBJECTIVE To examine whether auditory evoked fields (AEFs) can be used to objectively evaluate hearing in patients with absent auditory brainstem responses (ABRs) due to auditory neuropathy. METHODS Subjects were 3 patients with auditory neuropathy, 1 male aged 29 years and 2 females aged 18 and 27 years, with absence of click evoked ABRs for bilateral ear stimuli at a level of 105 dB nHL. All patients also had optic atrophy. AEFs were measured with a helmet-shaped magnetoencephalography system for 2.0 kHz tone bursts of 60 ms duration to the unilateral ear. RESULTS Bihemispherical AEF responses were clearly recorded in all three patients for either left or right ear stimulus. Although the latencies of N100m were severely prolonged and amplitudes were considerably decreased compared to the normal range of N100m responses in our facilities, N100m latency of AEF was shorter in the contralateral hemisphere to the stimulated ear, as usually found in normal subjects, despite the abnormal delay in N100m latency in all conditions. CONCLUSIONS Presence and abnormality of auditory cortical responses can be evaluated by AEFs in patients with auditory neuropathy even under null responses in ABRs. SIGNIFICANCE AEFs are useful to evaluate residual hearing in patients with auditory neuropathy.

Unique migration of a dental needle into the parapharyngeal space: successful removal by an intraoral approach and simulation for tracking visibility in X-ray fluoroscopy.

Objectives: The first objective was to describe a novel case of migration of a broken dental needle into the parapharyngeal space. The second was to address the importance of simulation elucidating visualization of such a thin needle under X-ray fluoroscopy. Methods: Clinical case records (including computed tomography [CT] and surgical approaches) were reviewed, and a simulation experiment using a head phantom was conducted using the same settings applied intraoperatively. Results: A 36-year-old man was referred after failure to locate a broken 31-G dental needle. Computed tomography revealed migration of the needle into the parapharyngeal space. Intraoperative X-ray fluoroscopy failed to identify the needle, so a steel wire was applied as a reference during X-ray to locate the foreign body. The needle was successfully removed using an intraoral approach with tonsillectomy under surgical microscopy. The simulation showed that the dental needle was able to be identified only after applying an appropriate compensating filter, contrasting with the steel wire. Conclusion: Meticulous preoperative simulation regarding visual identification of dental needle foreign bodies is mandatory. Intraoperative radiography and an intraoral approach with tonsillectomy under surgical microscopy offer benefits for accessing the parapharyngeal space, specifically for cases medial to the great vessels.

Positive auditory cortical responses in patients with absent brainstem response.

OBJECTIVE To compare the detectability of the different auditory evoked responses in patients with retrocochlear lesion. METHODS The 40-Hz auditory steady state response (ASSR) and the N1m auditory cortical response were examined by magnetoencephalography in 4 patients with vestibular schwannoma, in whom the auditory brainstem response (ABR) was absent. RESULTS Apparent N1m responses were observed despite total absence of the ABR or absence except for small wave I in all patients, although the latency of N1m was delayed in most patients. On the other hand, clear ASSFs could be observed only in one patient. Very small 40-Hz ASSFs could be detected in 2 patients (amplitude less than 1fT), but no apparent ASSFs were observed in one patient, in whom maximum speech intelligibility was extremely low and the latency of N1m was most prolonged. CONCLUSION The N1m response and 40-Hz ASSR could be detected in patients with absent ABR, but the N1m response appeared to be more detectable than the 40-Hz ASSR. SIGNIFICANCE Combined assessment with several different evoked responses may be useful to evaluate the disease conditions of patients with retrocochlear lesions.

Outcomes of frontal mucoceles treated with conventional endoscopic sinus surgery.

Abstract Conclusion: Conventional endoscopic sinus surgery (CESS) is useful for frontal mucoceles. A patient with short anterior–posterior distance and bone thickening may need an axillary flap, Draf type IIb, or Draf type III procedure. Objective: To present outcomes of frontal mucoceles treated with CESS and predict risk factors for poor outcomes to help define surgical indications. Methods: A consecutive clinical series was reviewed retrospectively. The authors performed CESS without agger nasi resection (Draf type IIa) for 13 frontal sinus mucoceles in 12 patients between October 2011 and July 2013. Patient age, sex, blood eosinophil count, history of operation and co-existence of acute infection were compared. For the condition of the frontal sinus, anterior–posterior distance and width of frontal recess, bone thickening of the frontal recess, bone absorption due to continuous pressure by mucocele and anatomy of the frontal recess was noted. Results: All operations were done without a navigation system. The post-operative course was uneventful in all 12 patients, and all symptoms gradually receded. Among 13 mucoceles, one frontal sinus (7.7%) closed during follow-up.

Bilateral endoscopic endonasal marsupialization of nasopalatine duct cyst

Nasopalatine duct cysts are the most common non-odontogenic cysts in the maxilla, and are conventionally treated through a sublabial or palatine approach. Recently, the endoscopic approach has been used, but experience is extremely limited. We treated a 29-year-old male with nasopalatine duct cyst by endoscopic marsupialization, but paresthesia of the incisor region occurred after surgery. This paresthesia gradually remitted within 6 months. The nasopalatine nerve, which innervates the upper incisor region, enters two lateral canals separately at the nasal floor and exits the central main canal at the palate. Damage to the bilateral nasopalatine nerves might lead to paresthesia, so we recommend careful examination for nerve fibers during endoscopic surgery, especially if fenestration is performed on both sides.

Preservation of cochlear function in Fabp3 (H-Fabp) knockout mice

Fatty acid-binding protein 3 (Fabp3) is an intracellular lipid trafficking protein that mediates energy metabolism and long-chain fatty acid-related signaling. Fabp3 is expressed in the spiral ganglion neurons and supporting cells of the organ of Corti. However, it is unclear what role Fabp3 plays in the cochlea. Here, we demonstrated that the ABR thresholds of young and aged Fabp3 knockout mice were unchanged compared with those of wild-type mice. Compared with the wild-type mice, the adult mutant mice demonstrated no differences in their vulnerability to acoustic overexposure. These results suggest that Fabp3 deficiency alone does not adversely affect hearing function.

Giant cell reparative granuloma of the temporal bone successfully resected with preservation of hearing.

OBJECTIVE To describe a case of giant cell reparative granuloma of the temporal bone which extended into the middle-ear cavity, and which was successfully treated surgically via a transmastoid approach, with hearing preservation. CASE A 37-year-old man presented with a one-year history of right-sided hearing loss, complicated by a three-month history of otalgia and a sensation of aural fullness. Computed tomography and magnetic resonance imaging demonstrated an osteolytic tumour lesion in the right temporal bone. The diagnosis was confirmed by biopsy from the mastoid lesion. INVESTIGATION AND INTERVENTION: Pure-tone audiometry, computed tomography and magnetic resonance imaging were conducted, followed by total resection. RESULT The giant cell reparative granuloma of the temporal bone was completely resected, with preservation of hearing. CONCLUSION Although this patients giant cell reparative granuloma of the temporal bone extended into the middle-ear cavity, total resection was achieved, with preservation of hearing. To the best of our knowledge, hearing preservation following resection of giant cell reparative granuloma of the temporal bone has not previously been reported.

Factors Affecting the Variation of Maximum Speech Intelligibility in Patients With Sensorineural Hearing Loss Other Than Apparent Retrocochlear Lesions.

Objectives To examine the relationship between speech intelligibilities among the similar level of hearing loss and threshold elevation of the auditory brainstem response (ABR). Methods The relationship between maximum speech intelligibilities among similar levels of hearing loss and relative threshold elevation of the click-evoked ABR (ABR threshold - pure tone average at 2,000 and 4,000 Hz) was retrospectively reviewed in patients with sensorineural hearing loss (SNHL) other than apparent retrocochlear lesions as auditory neuropathy, vestibular schwannoma and the other brain lesions. Results Comparison of the speech intelligibilities in subjects with similar levels of hearing loss found that the variation in maximum speech intelligibility was significantly correlated with the threshold elevation of the ABR. Conclusion The present results appear to support the idea that variation in maximum speech intelligibility in patients with similar levels of SNHL may be related to the different degree of dysfunctions of the inner hair cells and/or cochlear nerves in addition to those of outer hair cells.

Masking effects in patients with auditory neuropathy-possible involvement of suppression mechanism caused by normal outer hair cell function.

Objective Variations in the effects of masking noise were evaluated in different pathologies of sensorineural hearing loss. Study Design Retrospective chart review. Setting Tertiary referral center. Patients Fifty-five ears of 30 patients with sensorineural hearing loss who underwent noise audiometry in the Department of Otolaryngology–Head and Neck Surgery, Tohoku University Hospital, since 2010, because of complaints of hearing difficulty in noisy environments. Main Outcome Measures Masked threshold for narrow band and white noise. Results and Discussion Masking effects in patients with auditory neuropathy were significantly larger than those in patients with other types of hearing losses. Masking effects of broad band white noise were greater than those of narrow band noise. Masking effects could be observed for white noise even in the elevated unmasked threshold region, where little contribution of excitatory masking effect would be expected. The present findings support the idea that the suppression mechanism caused by normal outer hair cell function is important in the masking phenomenon in patients with auditory neuropathy.

Minimally invasive transnasal approach to infratemporal fossa abscess

BACKGROUND Infratemporal fossa abscess following odontogenic infection is not rare, and usually occurs as a sequela of dental disease. Infratemporal fossa abscess was previously treated with the combination of buccal incision and temporal incision, or via a transoral approach. METHOD This paper reports a case of infratemporal fossa abscess in a 51-year-old female. RESULTS The abscess was drained transnasally via an endoscopic modified medial maxillectomy approach, preserving the inferior turbinate and nasolacrimal duct. The pain remitted the next day and trismus had diminished in one week. CONCLUSION The transnasal approach with endoscopic modified medial maxillectomy is a direct, minimally invasive method that provides a direct field of view for drainage of infratemporal fossa abscess. This approach is recommended for infratemporal fossa abscess.