Estimation of Hearing Thresholds with Auditory Steady-State Responses to Narrow-Band Chirps in Children.

OBJECTIVE: The aim of this study was to evaluate the utility of auditory steady-state responses (ASSRs) to narrow-band chirps (NB-chirps) for estimating hearing levels in children. DESIGN: Thresholds from the NB-chirp ASSR were evaluated in 30 sedated children with normal hearing or hearing loss. The correlation between the NB-chirp ASSR and pure-tone audiometry (PTA) thresholds was analyzed, and the difference score (DS) between these thresholds was calculated. Data from the NB-chirp ASSR were compared to retrospective data from conventional ASSR to exponentially amplitude-modulated tones in 25 sedated children. RESULTS: Positive correlations between the NB-chirp ASSR and PTA thresholds were found at 500, 1,000, 2,000, and 4,000 Hz. Multiple comparisons of the DSs for the NB-chirp ASSR and PTA revealed significant differences at 500-2,000 Hz and 4,000 Hz, as well as 1,000-2,000 Hz, and 4,000 Hz. Comparisons of the DSs demonstrated that the DS of the NB-chirp ASSR was significantly smaller than that of the conventional ASSR at 2,000 Hz. Furthermore, the testing times for the NB-chirp ASSR were significantly shorter than those for the conventional ASSR. CONCLUSION: The NB-chirp ASSR closely reflected the PTA thresholds, and the testing time was shorter than that of the conventional ASSR. Thus, this study demonstrated that the NB-chirp ASSR is useful for hearing threshold estimation in children.

The use of basic fibroblast growth factor to treat intractable Bell's palsy administered via transcanal endoscopic ear surgery.

PURPOSE: Facial nerve decompression surgery is an invasive procedure which has hitherto been the main option for patients with severe intractable Bell's palsy which is resistant to drug treatment. We have developed a new salvage treatment for such patients by using minimally invasive transcanal endoscopic ear surgery (TEES) to deliver the biological regenerative agent, basic fibroblast growth factor (bFGF), to the damaged facial nerve. MATERIALS AND METHODS: An endoscopic salvage treatment group was studied prospectively and was made up of severe intractable Bell's palsy patients who did not respond to high dose steroid treatment and had an ENoG value of 5 % or less. This surgery group was retrospectively compared to a similar control group who had received high dose steroid only. RESULTS: Complete recovery to House-Brackmann (HB) Grade I was achieved by 44.8 % of the endoscopic salvage treatment group which was significantly higher than the 21.2 % of the control group at one-year follow up. Patients with an ENoG value of 1 % to 5 % exhibited a significantly higher complete recovery rate of 71.4 % in the endoscopic salvage treatment group than the 28.6 % of the control group. In addition, no complications were observed including hearing loss. CONCLUSIONS: bFGF delivered via TEES shows considerable promise as a new salvage treatment of severe intractable Bell's palsy that is resistant to high dose steroid treatment without the risks presented by facial nerve decompression surgery.

Expression and localization of diacylglycerol kinase ζ in guinea pig cochlea and its functional implication under noise-exposure stress conditions.

Cochlear hair cells are essential for the mechanotransduction of hearing. Sensorineural hearing loss can be irreversible because hair cells have a minimal ability to repair or regenerate themselves once damaged. In order to develop therapeutic interventions to prevent hair cell loss, it is necessary to understand the signaling pathway operating in cochlear hair cells and its alteration upon damage. Diacylglycerol kinase (DGK) regulates intracellular signal transduction through phosphorylation of lipidic second messenger diacylglycerol. We have previously reported characteristic expression and localization patterns of DGKs in various organs under pathophysiological conditions. Nevertheless, little is known about morphological and functional aspects of this enzyme family in the cochlea. First RT-PCR analysis reveals predominant mRNA expression of DGKα, DGKε and DGKζ. Immunohistochemical analysis shows that DGKζ localizes to the nuclei of inner hair cells (IHCs), outer hair cells (OHCs), supporting cells and spiral ganglion neurons in guinea pig cochlea under normal conditions. It is well known that loud noise exposure induces cochlear damage, thereby resulting in hair cell loss. In particular, OHCs are highly vulnerable to noise exposure than IHCs. We found that after 1 week of noise exposure DGKζ translocates from the nucleus to the cytoplasm in damage-sensitive OHCs and gradually disappears thereafter. In sharp contrast, DGKζ remains to the nucleus in damage-resistant IHCs. These results suggest that DGKζ cytoplasmic translocation is well correlated with cellular damage under noise-exposure stress conditions and is involved in delayed cell death in cochlear outer hair cells.

Ergonomics of Various Modalities for Ear Surgery.

Objective: Evaluate ergonomic differences of various modalities for performing middle ear surgery. Study Design: Observational study. Setting: Two academic tertiary care centers. Methods: Attending physicians and residents performing middle ear surgery were photographed intraoperatively. Intraoperative photographs were analyzed using the validated Rapid Upper Limb Assessment (RULA) tool to measure musculoskeletal disease (MSD) risk. Descriptive statistics and significance testing were used to characterize and compare ergonomic differences between surgical modalities. Multivariable ordinal regression was performed to assess factors associated with increased MSD risk, as determined by the final RULA score. Results: Most of our 110 intraoperative photos featured attendings (82.7%) performing combined middle ear surgery and mastoidectomy (60.0%). Body angles and the final RULA score varied significantly among modalities. On subset analysis, microscopic surgery exhibited significantly worse wrist, trunk, and neck angles compared to endoscopic and exoscopic surgery. Exoscopic surgery had significantly lower final RULA scores than both endoscopic and microscopic surgery, indicating significantly lower MSD risk. Microscopic and endoscopic surgery final scores did not vary significantly. In a multivariable ordinal regression of factors associated with increased RULA score, exoscopic surgery had statistically significantly less ergonomic risk relative to microscopic surgery (odds ratio = 0.12, 95% confidence interval = [0.03-0.43]). Conclusion: Exoscopic, endoscopic, and microscopic surgery all featured low ergonomic risk, although exoscopic middle ear surgery demonstrated the lowest risk profile among studied surgical modalities. This demonstrates the importance of using each modality in combination with other ergonomic interventions to provide meaningful musculoskeletal benefits.

Open-type cholesteatoma is the predictive factor for residual disease in congenital cholesteatoma treated with TEES.

OBJECTIVE: To determine the predictive factors for residual disease occurring after surgical removal of congenital cholesteatomas and whether these predictive factors differ between microscopic ear surgery (MES) using data from the literature and transcanal endoscopic ear surgery (TEES) using data from our own institution. METHODS: Twenty-three patients with a congenital cholesteatoma who underwent surgical treatment at Yamagata University Hospital between December 2011 and December 2017 were retrospectively investigated. We divide TEES into three different approaches: non-powered TEES, powered TEES and dual MES/TEES. Main outcome measures were Potsic stage, closed or open congenital cholesteatoma type, TEES surgical approach, appearance of residual disease, tympanoplasty type and hearing outcome. RESULTS: A logistic regression analysis was conducted on the Potsic stage, closed or open type, TEES surgical approach and age to obtain the odds ratio for residual disease. The chance of residual disease significantly increased in the presence of an open-type congenital cholesteatoma (odds ratio: 30.82; 95 % confidence interval: 1.456-652.3; p = 0.0277), but not for any of the other factors including Potsic stage. The timing of the confirmation of residual disease after ossicular chain reconstruction was analyzed using a Kaplan-Meier analysis. The residual disease rate was significantly higher with an open-type congenital cholesteatoma (log-rank test, p < 0.05). In addition, all residual disease occurred within three years after surgery. CONCLUSIONS: Our results showed that an open-type congenital cholesteatoma is the strongest predictive factor for residual disease when removing a congenital cholesteatoma by TEES.

Clinical course of five patients definitively diagnosed with idiopathic perilymphatic fistula treated with transcanal endoscopic ear surgery.

Objectives: An idiopathic perilymphatic fistula (PLF) can be difficult to diagnose because patients present with sudden sensorineural hearing loss (SSHL) and/or vestibular symptoms without any preceding events. In such cases, we currently test for cochlin-tomoprotein (CTP) to confirm the diagnosis of idiopathic PLF because CTP is only detected in the perilymph. In this study, we report the clinical course of five patients definitively diagnosed with idiopathic PLF who underwent PLF repair surgery using transcanal endoscopic ear surgery (TEES). Patients and methods: Five patients were initially treated with intratympanic dexamethasone for SSHL, at which time a CTP test was also performed (preoperative CTP test). Due to refractory hearing loss and/or fluctuating disequilibrium, PLF repair surgery using TEES was performed to seal the oval and round windows using connective tissue and fibrin glue. These patients were diagnosed with definite idiopathic PLF based on pre- or intra-operative CTP test results (negative, < 0.4 ng/mL; intermediate, 0.4-< 0.8 ng/mL; and positive, > 0.8 ng/mL). We evaluated pre- and intra-operative CTP values, intraoperative surgical findings via a magnified endoscopic view, and pre- and post-operative changes in averaged hearing level and vestibular symptoms. Results: Pre- and intra-operative CTP values were positive and intermediate in three patients, positive and negative in one patient, and negative and positive in one patient. None of the patients had intraoperative findings consistent with a fistula between the inner and middle ears or leakage of perilymph. Only two patients showed a slight postoperative recovery in hearing. Four patients complained of disequilibrium preoperatively, of whom two had resolution of disequilibrium postoperatively. Conclusion: A positive CTP test confirms PLF in patients without obvious intraoperative findings. The CTP test is considered more sensitive than endoscopic fistula confirmation. We consider that CTP test results are important indicators to decide the surgical indication for idiopathic PLF repair surgery. In our experience with the five cases, two of them showed improvements in both hearing and vestibular symptoms.

[Efficacy of early combined high-dose steroid + PGE1 treatment for sudden deafness].

The efficacy of combined high-dose steroid and PGE1 treatment initiated immediately after the onset of sudden deafness was analyzed with the outcome of 174 patients begun on treatment within 7 days of the onset of sudden deafness. Four potential prognostic factors (days from onset to treatment, age, initial hearing level, presence of vertigo) and hearing outcome were examined with a multiple logistic regression analysis. Days from onset to treatment and age significantly correlated with hearing improvement. The efficacy of the treatment of patients begun on treatment within 3 days of the onset was significantly better than that of patients on treatment 4-7 days after the onset (p < 0.001). In the examination of patients younger than 50 years, the efficacy of the treatment of patients begun on treatment within 3 days of the onset didn't differ significantly from that of patients on treatment 4-7 days after the onset. On the other hand, in the examination of patients aged 50 years and older, the efficacy of the treatment of patients begun on treatment within 3 days of the onset was significantly better than that of patients on treatment 4-7 days after the onset (p < 0.001). These results suggest that significant efficacy may be expected from the combined high-dose steroid + PGE1 treatment, if its use is started within 7 days of the onset of sudden deafness, and started within 3 days of the onset of sudden deafness in patients 50 years old and older.

A Minority Population of Non-dye-decolorizing Bacillus subtilis enhances the Azo Dye-decolorizing Activity of Enterococcus faecalis.

Microbes live in communities in biological wastewater treatment plants and in the intestines. However, limited information is currently available on the mechanisms by which minority bacterial populations assist other bacteria besides syntrophic relationships as well as on the microbial food web. Therefore, the present study investigated the effects of non-dye-decolorizing Bacillus subtilis strain S4ga at population levels ranging between 0.04 and 4% on the activity of dye-decolorizing Enterococcus faecalis strain T6a1 using a dye decolorization assay. The results obtained revealed that the minority population of B. subtilis S4ga enhanced the dye-decolorizing activity of E. faecalis T6a1, resulting in a shorter lag time and longer active time of dye decolorization. These effects were related to redox potential values rather than O2 concentrations. Comparisons of the extracellular metabolites in individual incubations of E. faecalis T6a1 and B. subtilis S4ga and a co-incubation suggested a mutual relationship through the cross-feeding of specific amino acids (tyrosine, methionine, tryptophan, phenylalanine, valine, and leucine from B. subtilis S4ga to E. faecalis T6a1; glutamine, histidine, aspartic acid, and proline from E. faecalis T6a1 to B. subtilis S4ga). An ana-lysis of intracellular primary metabolites indicated that the arginine deiminase (ADI) pathway, an ATP-producing energy-generating process, was more strongly activated in co-incubated E. faecalis T6a1 than in E. faecalis T6a1 incubated alone. These results suggest that a co-incubation with B. subtilis S4ga promoted ATP production by E. faecalis T6a1 cells and enhanced its dye-decolorizing activity.

Benefits of High-Dose Corticosteroid and Antiviral Agent Combination Therapy in the Treatment of House-Brackman Grade VI Ramsay Hunt Syndrome.

OBJECTIVE: Few large-scale investigations have been conducted on treatment of House-Brackmann grade VI (HB grade VI) Ramsay Hunt syndrome (RHS) patients. We compared recovery rates among patients receiving a normal-dose corticosteroid (prednisolone [PSL] 60 mg/d) or high-dose corticosteroid (PSL 200 mg/d), both with or without an antiviral agents. Recovery rates were also examined based on the order of presentation of herpetic vesicles versus facial palsy. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: A total of 128 patients with HB grade VI RHS were treated in our department between 1995 and 2017. These patients were divided into four treatment groups based on corticosteroid dosage and use of an antiviral agent. METHODS: We assessed treatment outcomes for HB grade VI patients together with logistic regression analysis to investigate factors that can impact treatment outcomes, that is, sex, age, days to start of treatment, PSL dosage, and antiviral agent administration. RESULTS: Recovery rates were best in the high-dose corticosteroid group with an antiviral agent (71.1%) in comparison with the normal-dose corticosteroid group with an antiviral agent (60.0%) or high-dose corticosteroid alone (57.1%). Significant factors for treatment outcomes were high-dose corticosteroid administration and early initiation of treatment. A better recovery rate was also found when the herpetic vesicles appeared before facial palsy. CONCLUSION: We showed that a combination of a high-dose corticosteroid and antiviral agent produced the best outcomes for patients with HB grade VI RHS. However, our results were not statistically significant because of small sample size.

The Feasibility and Treatment Results of Transcanal Endoscopic Myringoplasty.

OBJECTIVE: We reported on transcanal endoscopic myringoplasty in 25 cases preliminarily in 2014. Now our number of transcanal endoscopic myringoplasty reached to 209 ears and allowed us to adequately investigate the visibility, necessity of canalplasty, treatment results, and multivariate analysis. STUDY DESIGN: A prospective case series. SETTING: Tertiary referral center. PATIENTS: Transcanal endoscopic myringoplasty was performed on 209 ears in 201 patients between 2011 and 2019 and followed up over 1 year. METHODS: Preoperative endoscopic and microscopic views for the same patient were compared. We examined success rates at 1 year after surgery according to operation type, perforation size, operation side, gender, cause of perforation, and age, and also examined hearing results. Logistic regression analysis was performed to investigate the basic demographic and clinical characteristics of the patients associated with perforation closure. RESULTS: The anterior edge of the preoperative perforation was not visible under microscopy in 14.4% of patients. In contrast, endoscopic views revealed the entire tympanic membrane in one field. However, canalplasty was required in 2.4% of tympanic procedures due to difficulty of manipulation. The overall closure rate for perforations was 90.4%. Logistic regression analysis revealed that age > 11 was the only significant factor associated with perforation closure. The average reduction in air-bone gap was 12.1 dB. CONCLUSION: The endoscopic myringoplasty produced better visualization, the same or better closure rates, and the same or lower complication rates as compared with traditional microscopic techniques.

Ecophysiology of uncultured filamentous anaerobes belonging to the phylum KSB3 that cause bulking in methanogenic granular sludge.

A filamentous bulking of a methanogenic granular sludge caused by uncultured filamentous bacteria of the candidate phylum KSB3 in an upflow anaerobic sludge blanket (UASB) system has been reported. To characterize the physiological traits of the filaments, a polyphasic approach consisting of rRNA-based activity monitoring of the KSB3 filaments using the RNase H method and substrate uptake profiling using microautoradiography combined with fluorescence in situ hybridization (MAR-FISH) was conducted. On the basis of rRNA-based activity, the monitoring of a full-scale UASB reactor operated continuously revealed that KSB3 cells became active and predominant (up to 54% of the total 16S rRNA) in the sludge when the carbohydrate loading to the system increased. Batch experiments with a short incubation of the sludge with maltose, glucose, fructose, and maltotriose at relatively low concentrations (approximately 0.1 mM) in the presence of yeast extract also showed an increase in KSB3 rRNA levels under anaerobic conditions. MAR-FISH confirmed that the KSB3 cells took up radioisotopic carbons from [(14)C]maltose and [(14)C]glucose under the same incubation conditions in the batch experiments. These results suggest that one of the important ecophysiological characteristics of KSB3 cells in the sludge is carbohydrate degradation in wastewater and that high carbohydrate loadings may trigger an outbreak of KSB3 bacteria, causing sludge bulking in UASB systems.

Consistent removal of hair cells in vestibular end organs by time-dependent transtympanic administration of gentamicin in guinea pigs.

BACKGROUND: Vestibular hair cell loss and its role in balance disorders are not yet completely understood due largely to the lack of precise hair cell damage protocols. NEW METHOD: Our damage protocol aims to selectively remove type I hair cells in a way that produces consistent and predictable lesions that can be used for reliable inter-animal and inter-group comparison in balance research. This objective is achieved by transtympanic injection of gentamicin on both the round window membrane and oval window over a fixed time period followed by thorough washing. RESULTS: We achieved nearly total and consistent loss of type I hair cells at 94 % for the crista ampullaris of the lateral semicircular canal (LSC) and 86 % for the utricular macula with negligible loss of type II hair cells at 4% for the crista ampullaris of the LSC and 6% for the utricular macula. While the vestibular function was compromised in the relevant study group, this group had a zero mortality rate with no significant suppression of body weight gain. COMPARISON WITH EXISTING METHODS: Gentamicin is typically administered via intraperitoneal systemic injection or, more recently, transtympanic injection. The intraperitoneal method is simple, but mortality rate is high. The transtympanic injection method produces ototoxic damage but with inconsistent lesion size. This inconsistency prevents reliable comparisons among animals. CONCLUSIONS: This protocol employs a transtympanic injection method which selectively targets type I hair cells for removal in the vestibular epithelia in a time-dependent manner, uniformly damages vestibular function, and causes uniform hair cell loss.

Multicenter Study of Congenital Middle Ear Anomalies. Report on 246 Ears.

OBJECTIVES/HYPOTHESIS: Congenital middle ear anomalies represent a relatively rare condition. This study aimed to describe the characteristics and the surgical outcomes for patients with middle ear anomalies. METHODS: A multicenter study was conducted of consecutive patients with congenital middle ear anomalies who underwent primary surgical treatment between January 2008 and December 2017. Demographics, surgical procedures, and audiometric data were registered into the institutional database. Hearing changes and postoperative air-bone gap (ABG) were evaluated 1 year after surgery. RESULTS: A total of 246 patients (246 ears) (median age: 14 years, range: 4-75 years old) were included in this study. Anomalies were subdivided using the Teunissen and Cremers classification: 53 ears (22%) were categorized as class I, comprising only stapes ankylosis; 35 ears (14%) as class II, having ossicular chain anomalies with stapes ankylosis; 139 ears (57%) as class III, having ossicular chain anomalies with a mobile stapes-footplate; and 19 ears (8%) as class IV, with aplasia of the oval window. Evaluation of hearing outcomes for 198 ears with more than 1 year of follow-up revealed that good postoperative ABG (≤20 dB) was achieved in 82% of class I, 68% of class II, 74% of class III, and 23% of class IV anomalies. The postoperative ABG in class IV was significantly worse than in class I (P < .001) or class III (P < .01). CONCLUSIONS: This study demonstrated that class III anomalies comprised the majority of middle ear anomalies and surgical outcomes for class IV anomalies are unfavorable. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E2323-E2328, 2021.

Purification, characterization and molecular cloning of a novel endo-beta-N-acetylglucosaminidase from the basidiomycete, Flammulina velutipes.

Endo-beta-N-acetylglucosaminidases are thought to be key enzymes in the catabolism of asparagine-linked oligosaccharides. However, little is known about the enzymes of this type in basidiomycetes. We investigated endo-beta-N-acetylglucosaminidases in basidiomycetes using fluorescence-labeled glycoasparagines as substrates. Flammulina velutipes showed high activity and its enzyme was named endo-beta-N-acetylglucosaminidase FV (Endo FV). The enzyme purified from the fruiting bodies of F. velutipes was separated into two forms. Endo FV was specific for high mannose and hybrid-type oligosaccharides. The enzyme was remarkably less active against asparagine-linked oligosaccharides attached to glycoproteins. It transferred an asparagine-linked oligosaccharide to Glc, but not to Gal. cDNA of Endo FV was cloned. It was composed of a 996-bp open reading frame encoding 331 amino acid residues. A recombinant Endo FV expressed in Escherichia coli showed enzymatic activity. The Endo FV gene in the genome of F. velutipes had no introns. The gene encoding Endo FV showed little homology with genes of known endo-beta-N-acetylglucosaminidases. A chitinase active site motif existed in the deduced primary structure, indicating that Endo FV belongs to glycoside hydrolase family 18. The deduced amino acid sequence of Endo FV had regions conserved in class III chitinases from fungi though it showed little homology with the sequence of any other endo-beta-N-acetylglucosaminidases. A folding model of Endo FV indicated it to be homologous with the tertiary structure of Endo H which is quite similar in specificity for asparagine-linked oligosaccharides. This study suggests that Endo FV may become similar to Endo H in substrate specificity as a result of evolutionary convergence.

Effectiveness of BCG vaccination to aged mice.

BACKGROUND: The tuberculosis (TB) still increases in the number of new cases, which is estimated to approach 10 million in 2010. The number of aged people has been growing all over the world. Ageing is one of risk factors in tuberculosis because of decreased immune responses in aged people. Mycobacterium bovis Bacillus Calmette Guérin (BCG) is a sole vaccine currently used for TB, however, the efficacy of BCG in adults is still a matter of debate. Emerging the multidrug resistant Mycobacterium tuberculosis (MDR-TB) make us to see the importance of vaccination against TB in new light. In this study, we evaluated the efficacy of BCG vaccination in aged mice. RESULTS: The Th1 responses, interferon-γ production and interleukin 2, in BCG inoculated aged mice (24-month-old) were comparable to those of young mice (4- to 6-week-old). The protection activity of BCG in aged mice against Mycobacterium tuberculosis H37Rv was also the same as young mice. CONCLUSION: These findings suggest that vaccination in aged generation is still effective for protection against tuberculosis.

Regenerative Effect of a ROCK Inhibitor, Y-27632, on Excitotoxic Trauma in an Organotypic Culture of the Cochlea.

In the past, most inner ear diseases were thought to start with the impairment of the sensory epithelium of the cochlea before subsequently progressing to secondary neural degeneration. However, recent studies show that loss of primary synapses accompanied by excitotoxic degeneration of peripheral axons is likely to be the underlying pathology in sensorineural hearing loss. Rho-associated coiled-coil containing protein kinase (ROCK) inhibition has been reported to have neuroprotective and regenerative effects on synaptic pathways. Therefore, we analyzed the effect of ROCK inhibition using Y-27632 in a model of peripheral axonal damage in the spiral ganglion neurons created using the glutamate agonists, N-methyl-D-aspartate (NMDA) and kainic acid, to induce excitotoxic trauma in the explanted cochlea. The number of axons projecting to hair cells in the cochlea treated with Y-27632 was significantly greater than those in the cochlea treated only with NMDA + kainic acid. Furthermore, there was a significant increase in synapses between the spiral ganglion and the inner hair cells in the cochlea treated with Y-27632. The findings of this study suggest that ROCK inhibition could be a potential strategy for the regeneration of peripheral axons in the spiral ganglion and synapse formation in the inner hair cells of a cochlea that has sustained excitotoxic injury, which is one of the primary etiologies of inner ear disease.

Measurement of the Pediatric and Adult Osseous External Auditory Canal: Implications for Transcanal Endoscopic Ear Surgery.

OBJECTIVE: To develop a method for measuring the diameter of the osseous external auditory canal (OEAC) in pediatric and adult patients. STUDY DESIGN: Retrospective analysis of imaging data from patients with a cholesteatoma who underwent transcanal endoscopic ear surgery (TEES) to remove the cholesteatoma by analyzing preoperative sagittal cone beam computed tomography (CBCT) images using ImageJ. METHODS: Pediatric and adult patients were included who underwent TEES for a cholesteatoma between December 2011 and March 2015 and had available preoperative CBCT scans. Sagittal CT imaging data were analyzed by ImageJ to measure the maximum and minimum Feret diameters along the OEAC. The output data were then analyzed to determine the smallest maximum and smallest minimum Feret diameters for each patient. RESULTS: Fifty-one patients ranging in age from 3 to 83 years old were included in this study. The smallest maximum Feret diameter ranged from 6.5 to 10.1 mm (mean: 8.0 mm) for pediatric patients (<16 years of age) and 6.9 to 15.0 mm (mean: 8.9 mm) for adult patients, while the smallest minimum Feret diameter ranged from 3.6 to 5.9 mm (mean: 5.1 mm) for pediatric patients and 3.4 to 6.4 mm (mean: 5.4 mm) for adult patients. Moreover, the smallest maximum Feret diameters of children were significantly smaller than those of adults. CONCLUSION: We have developed a novel method for measuring the diameter along the OEAC and determining its narrowest site. This method can be incorporated into the preoperative evaluation of patients who are candidates for TEES.

The effect of insulin-like growth factor 1 on the recovery of facial nerve function in a guinea pig model of facial palsy.

The efficacy of insulin-like growth factor 1 (IGF-1) in the treatment of peripheral facial nerve palsy was investigated using an animal model. The facial nerve within the temporal bone was exposed and compressed by clamping. The animals were treated with either IGF-1 or saline which was topically administered by a gelatin-based sustained-release hydrogel via an intratemporal route. The recovery from facial nerve palsy was evaluated at 8 weeks postoperatively based on eyelid closure, complete recovery rate, electroneurography and number of axons found on the facial nerve. IGF-1 treatment resulted in significant improvement in the changes of the degree of eyelid closure over the total time period and complete recovery rate. A separate study showed that IGF-1 receptor mRNA was expressed in facial nerves up to 14 days after the nerve-clamping procedure. IGF-1 was thus found to be effective in the treatment of peripheral facial nerve palsy when topically applied using a sustained-release gelatin-based hydrogel via an intratemporal route.

Brain Abscess as a Rare Complication of Primary Extranodal Nasal-type Natural Killer/T-cell Lymphoma.

We present the case of a 58-year-old Japanese woman with a natural killer T (NK/T)-cell lymphoma complicated by brain abscess. NK/T-cell lymphomas represent a rare type of lymphoma derived from either activated NK cells or, rarely, cytotoxic T cells. They are aggressive Epstein-Barr virus (EBV)-associated lymphomas that involve mainly the nasal cavity. Brain abscess associated with primary extranodal nasal-type NK/T-cell lymphoma is extremely uncommon: to our knowledge, this is the first reported case of this lymphoma with brain abscess as the initial clinical manifestation. Endoscopic surgery was performed for definitive diagnosis under intraoperative navigation system. Chemotherapy followed by radiotherapy was performed and was effective: 72 months later the tumor has not recurred. Recommendations of endoscopic management for diagnosis and treatment of this rare neoplasm are discussed.

Facial nerve and chorda tympani schwannomas: Case series, and advantages of using non-rigid registration of post-enhanced 3D-T1 Turbo Field Echo and CT images (TURFECT) in their diagnosis and surgical treatment.

OBJECTIVE: Facial nerve schwannomas (FNSs) and chorda tympani schwannomas are very rare. Diagnosis of these tumors is sometimes difficult, and treatment consensus has not yet been reached. We report here a series of cases of FNS and chorda tympani schwannoma and highlight the usefulness of our newly developed technique of non-rigid registration of post-enhanced 3D-T1 Turbo Field Echo and CT images (TURFECT) in their diagnosis and treatment. METHODS: MRI images were adjusted with the corresponding CT images in terms of angle and position in order to index the anatomical structures. The well-enhanced T1-Gd+ lesions of tumors having good blood flow show up as bright red after color mapping. RESULTS: Between 2014 and 2018, five patients were diagnosed with schwannomas in the temporal bone: three with FNS and two with chorda tympani schwannoma. Gd-enhanced MRI showed only a high-intensity mass, and we could not detect the relationship between tumor-like mass and bone (including the ossicles) by MRI only. In contrast, TURFECT was very useful for diagnosing the precise location, allowing us to decide on an endoscopic surgical plan in some of our cases. An endoscope enabled visualization of the medial wall of the tympanic cavity and the status of the tumors, thus we could successfully perform transcanal endoscopic biopsy and resections. CONCLUSION: TURFECT can be very useful for diagnosis of FNSs and chorda tympani schwannomas and for deciding surgical treatments such as a transcanal endoscopic approach.