Prediction of Cochlear Implant Fitting by Machine Learning Techniques.

OBJECTIVE: This study aimed to evaluate the differences in electrically evoked compound action potential (ECAP) thresholds and postoperative mapping current (T) levels between electrode types after cochlear implantation, the correlation between ECAP thresholds and T levels, and the performance of machine learning techniques in predicting postoperative T levels. STUDY DESIGN: Retrospective case review. SETTING: Tertiary hospital. PATIENTS: We reviewed the charts of 124 ears of children with severe-to-profound hearing loss who had undergone cochlear implantation. INTERVENTIONS: We compared ECAP thresholds and T levels from different electrodes, calculated correlations between ECAP thresholds and T levels, and created five prediction models of T levels at switch-on and 6 months after surgery. MAIN OUTCOME MEASURES: The accuracy of prediction in postoperative mapping current (T) levels. RESULTS: The ECAP thresholds of the slim modiolar electrodes were significantly lower than those of the straight electrodes on the apical side. However, there was no significant difference in the neural response telemetry thresholds between the two electrodes on the basal side. Lasso regression achieved the most accurate prediction of T levels at switch-on, and the random forest algorithm achieved the most accurate prediction of T levels 6 months after surgery in this dataset. CONCLUSION: Machine learning techniques could be useful for accurately predicting postoperative T levels after cochlear implantation in children.

Prediction of Cochlear Implant Effectiveness With Surface-Based Morphometry.

OBJECTIVE: This study aimed to determine whether surface-based morphometry of preoperative whole-brain three-dimensional T1-weighted magnetic resonance imaging (MRI) images can predict the clinical outcomes of cochlear implantation. STUDY DESIGN: This was an observational, multicenter study using preoperative MRI data. SETTING: The study was conducted at tertiary care referral centers. PATIENTS: Sixty-four patients with severe to profound hearing loss (≥70 dB bilaterally), who were scheduled for cochlear implant (CI) surgery, were enrolled. The patients included 19 with congenital hearing loss and 45 with acquired hearing loss. INTERVENTIONS: Participants underwent CI surgery. Before surgery, high-resolution three-dimensional T1-weighted brain MRI was performed, and the images were analyzed using FreeSurfer. MAIN OUTCOME MEASURES: The primary outcome was monosyllable audibility under quiet conditions 6 months after surgery. Cortical thickness residuals within 34 regions of interest (ROIs) as per the Desikan-Killiany cortical atlas were calculated based on age and healthy-hearing control regression lines. RESULTS: Rank logistic regression analysis detected significant associations between CI effectiveness and five right hemisphere ROIs and five left hemisphere ROIs. Predictive modeling using the cortical thickness of the right entorhinal cortex and left medial orbitofrontal cortex revealed a significant correlation with speech discrimination ability. This correlation was higher in patients with acquired hearing loss than in those with congenital hearing loss. CONCLUSIONS: Preoperative surface-based morphometry could potentially predict CI outcomes and assist in patient selection and clinical decision making. However, further research with larger, more diverse samples is necessary to confirm these findings and determine their generalizability.

Application of Machine Learning to Predict Hearing Outcomes of Tympanoplasty.

OBJECTIVE: This retrospective study aimed to evaluate the performance of machine learning techniques in predicting air-bone gap after tympanoplasty compared with conventional scoring models and to identify the influential factors. METHODS: We reviewed the charts of 105 patients (114 ears) with chronic otitis media who underwent tympanoplasty. Two numerical scoring systems (middle ear risk index [MERI] and ossiculoplasty outcome parameter staging [OOPS]) and three algorithms (random forest [RF], support vector machine [SVM], and k nearest neighbor [kNN]) were created. Experimental variables included age, preoperative air-bone gap, soft-tissue density lesion in the tympanic cavity in CT, otorrhea, surgical history, ossicular bone problems in CT, tympanic perforation location, perforation type (central or marginal), grafting material, smoking history, endoscopy use, and the operator whose experience was 20 years or longer, or shorter. Binary classification, postoperative air-bone gap ≤15 or >15 dB, and multiclass classification, classification into seven categories by 10 dB, were performed, and the percentages of correct prediction were calculated. The importance of features in the RF model was calculated to identify influential factors. RESULTS: The percentages of correct prediction in binary classification were 62.3%, 72.8%, 81.5%, 81.5%, and 81.5% in MERI, OOPS, RF, SVM, and kNN, respectively, and those in multiclass classification were 29.8%, 21.9%, 63.1%, 44.7%, and 50% in the same order. The RF model suggested larger preoperative air-bone gap, and older age could make the postoperative air-bone gap larger. CONCLUSION: The machine learning techniques, especially the RF model, are promising methods for precise postoperative air-bone gap prediction. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:2371-2378, 2023.

Cholesterol granuloma in facial nerve canal presenting with facial nerve paralysis.

Cholesterol granulomas (CGs) are frequently found in the temporal bone, but their presence in the facial nerve has not been reported. We report a case of a 58-year-old woman who presented with left facial palsy caused by a CG that appeared to have originated in the facial nerve. Temporal bone computed tomography (CT) revealed soft tissue masses in the left middle ear spaces, and the facial canal was dilated from the genu to the vertical portion. Magnetic resonance imaging (MRI) revealed high signal intensity on T1-weighted images and partially high signal intensity on T2-weighted images, although no significant enhancement was observed on gadolinium-enhanced MRI. Surgical findings revealed CG in the middle ear spaces, but the facial canal remained intact and lacked continuity with the internal mass. Histopathological analysis verified the mass as a CG accompanied by cholesterol crystals. The mass was located within and continuous with the epineurium. These findings indicate that hemorrhage in the facial canal may have triggered the formation of the CG, causing left facial palsy due to increased pressure in the facial canal.

Stereotactic radiosurgery ensures an effective and safe long-term control of Koos grade IV vestibular schwannomas: a single-center, retrospective, cohort study.

PURPOSE: Stereotactic radiosurgery (SRS) is a standard treatment modality for vestibular schwannomas (VSs). However, there is a paucity of data on tumor control and neurological preservation for larger VSs. We aimed to investigate the long-term effectiveness of SRS for Koos grade IV compared with I-III VSs. METHODS: We included 452 patients with VSs (50 Koos grade IV and 402 Koos grade I‒III) who were treated with SRS at our institution from 1990 to 2021. Tumor control and functional preservation were calculated using the Kaplan-Meier method and compared between groups with the log-rank test. RESULTS: The median post-SRS follow-up period was 68 months. Progression-free survival rates were 91% at 5 and 10 years for Koos grade IV VSs, and 95% and 92%, respectively, for Koos grade I‒III VSs (p = 0.278). In Koos grade IV VSs, functional preservation rates of the facial and trigeminal nerves were both 96% at 5 years (both 98% for Koos grade I‒III VSs; facial, p = 0.410; trigeminal, p = 0.107). Hearing preservation rates were 61% at 5 years for Koos grade IV VSs and 78% for Koos grade I-III VSs (p = 0.645). Symptomatic transient tumor expansion was more common with Koos grade IV VSs (8.0% vs. 2.5%, p = 0.034), although all related symptoms diminished in accordance with tumor shrinkage. CONCLUSION: SRS may contribute to long-term tumor control and adequate neurological preservation in the treatment of Koos grade IV VSs, comparable to those in the treatment of Koos grade I‒III VSs.

Cochlear Implantation in Patients with Mitochondrial Gene Mutation: Decline in Speech Perception in Retrospective Long-Term Follow-Up Study.

Clinical evidence of the effectiveness of cochlear implantation for hearing loss with mitochondrial DNA mutation is limited. Most reports have only described short-term postoperative speech perception, which may not reflect the limitations of cochlear implantation caused by progressive retrocochlear dysfunction. The present study aimed to investigate long-term speech perception after cochlear implantation in patients with severe to profound hearing loss associated with mitochondrial DNA mutation. A retrospective chart review was performed on patients with mitochondrial DNA mutation who had undergone cochlear implantation at the Department of Otolaryngology and Head and Neck Surgery at the University of Tokyo Hospital. We extracted data on causative mutations, clinical types, clinical course, perioperative complications, and short-term and long-term postoperative speech perception. Nine patients with mitochondrial DNA mutation underwent cochlear implantation. The mean observation period was 5.5 ± 4.2 years (range, 1-13 years), and seven patients were followed for more than 3 years. Two of the seven patients who initially showed good speech perception exhibited deterioration during long-term follow-up. The absence of an acute progression of cognitive decline in patients, showing a gradual decrease in speech perception, suggests that the deterioration of speech perception was caused by progressive retrocochlear degeneration. Although most patients with mitochondrial DNA mutation maintained good speech perception for more than 3 years after cochlear implantation, retrocochlear degeneration could cause the deterioration of speech perception during long-term follow-up.

Alteration of Vestibular Function in Pediatric Cochlear Implant Recipients.

Background: Vestibular dysfunction is a complication of cochlear implantation (CI). Reports on the evaluation of vestibular function before and after CI are limited, especially in children. We investigated the effect of CI on vestibular function in pediatric patients. Patients and Methods: We routinely evaluated vestibular function before but not immediately after CI. Therefore, patients who underwent sequential bilateral CI were enrolled in this study. Seventy-three children who underwent sequential CI from 2003 to 2020 at our hospital were included. Since the vestibular function of the first implanted ear was evaluated before the second surgery for the contralateral ear, post-CI evaluation timing differed among the cases. The evaluation included a caloric test, a cervical vestibular-evoked myogenic potential (cVEMP) test, and a damped rotation test. The objective variables included the results of these tests, and the explanatory variables included the age at surgery, cause of hearing loss, electrode type, and surgical approach used. The associations of these tests were analyzed. Results: cVEMP was the most affected after CI (36.1%), followed by the caloric test (23.6%), and damped rotation test (7.8%). Cochleostomy was significantly more harmful than a round window (RW) approach or an extended RW approach based on the results of the caloric test (p = 0.035) and damped rotation test (p = 0.029). Perimodiolar electrodes affected the caloric test results greater than straight electrodes (p = 0.041). There were no significant associations among these tests' results. Conclusions: Minimally invasive surgery in children using a round window approach or an extended round window approach with straight electrodes is desirable to preserve vestibular function after CI.

Long-Term Outcomes of Stereotactic Radiosurgery for Trigeminal, Facial, and Jugular Foramen Schwannoma in Comparison with Vestibular Schwannoma.

Stereotactic radiosurgery (SRS) is known to provide excellent tumor control with functional preservation for vestibular schwannomas (VS), but its efficacy in the other major intracranial schwannomas including trigeminal (TS), facial (FS), and jugular foramen schwannomas (JFS) has not been established yet due to their rarity. We retrospectively analyzed data of 514 consecutive patients who had intracranial schwannomas (460 VS, 22 TS, 7 FS, and 25 JFS) and underwent SRS. The 5- and 10-year tumor control rates were 97% and 94% for VS, 100% and 100% for TS, 80% and 80% for FS, and 100% and 80% for JFS. Radiation-induced complications included one hydrocephalus for TS (4.5%), no cases for FS (0%), and one hydrocephalus and one lower palsy for JFS (8.0%). Through matched cohort analysis between patients with VS and each of the non-VS, we found no statistical difference in tumor control and radiation-induced adverse events. SRS seems to provide long-term tumor control with functional preservation for TS, FS and JFS and the efficacies are similar to VS.

Long-term Outcomes of Gamma Knife Radiosurgery for Treating Vestibular Schwannoma With a Lower Prescription Dose of 12 Gy Compared With Higher Dose Treatment.

OBJECTIVE: Gamma knife radiosurgery (GKRS) is commonly used to treat vestibular schwannomas (VSs). The risk of complications from GKRS decreases at lower doses, but it is unknown if long-term tumor control is negatively affected by dose reduction. STUDY DESIGN: This was a retrospective case review and analysis of patient data. SETTING: Tertiary referral center. PATIENTS: Patients with VSs who underwent GKRS between 1990 and 2007 at the authors' institution. INTERVENTION(S): The subjects were divided into two cohorts based on the prescribed doses of radiation received: a 12 Gy cohort (96 patients) with a follow-up period of 124 months and a >12 Gy cohort (118 patients) with a follow-up period of 143 months. MAIN OUTCOME MEASURES: Tumor control rates at 10 to 15 years, frequency of facial and trigeminal nerve complications, and hearing function. RESULTS: The 10 to 15-year tumor control rates were 95% in the 12 Gy cohort and 88% in the > 12 Gy cohort, but the differences were not significant. Compared with the >12 Gy cohort, facial and trigeminal nerve deficits occurred significantly less frequently in the 12 Gy cohort, with the 10-year cumulative, permanent deficit-free rates being 2% and 0%, respectively. Multivariate analyses revealed that treatment doses exceeding 12 Gy were associated with a significantly higher risk for cranial nerve deficits. The percentage of subjects retaining pure-tone average ≤ 50 dB at the final follow-up did not significantly differ between the cohorts (12 Gy cohort, 30% and >12 Gy cohort, 33%; p = 0.823). CONCLUSIONS: Dose reduction to 12 Gy for GKRS to treat VSs decreased facial and trigeminal nerve complications without worsening tumor control rates.

Long-Term Outcomes of Stereotactic Radiosurgery for Vestibular Schwannoma Associated with Neurofibromatosis Type 2 in Comparison to Sporadic Schwannoma.

The efficacy of radiosurgery for neurofibromatosis type 2 (NF2)-associated vestibular schwannoma (VS) remains debatable. We retrospectively analyzed radiosurgical outcomes for NF2-associated VS compared to sporadic VS using our database of 422 consecutive VS patients. Twenty-five patients with 30 NF2-associated VSs with a mean follow-up of 121 months were identified. NF2-associated VSs exhibited excellent tumor control (10-year cumulative rate, 92% vs. 92% in sporadic VSs; p = 0.945) and worse overall survival (73% vs. 97%; p = 0.005), mainly due to tumor progression other than the treated VSs. The presence of NF2 was not associated with failed tumor control via multivariate Cox proportional hazard analyses. No difference in radiation-induced adverse events (RAEs) was confirmed between cohorts, and prescription dose (hazard ratio 8.30, 95% confidence interval 3.19-21.62, p < 0.001) was confirmed as a risk for cranial nerve injuries via multivariate analysis. Further analysis after propensity score matching using age, volume, and sex as covariates showed that NF2-associated VSs exhibited excellent local control (100% vs. 93%; p = 0.240) and worse overall survival (67% vs. 100%; p = 0.002) with no significant difference in RAEs. Excellent long-term tumor control and minimal invasiveness may make radiosurgery a favorable therapeutic option for NF2 patients with small to medium VS, preferably with non-functional hearing or deafness in combination with postoperative tumor growth or progressive non-operated tumors, or with functional hearing by patients' wish.

Outcomes of cochlear implantations for mumps deafness: A report of four pediatric cases.

Mumps virus occasionally causes bilateral hearing loss. We report 4 cases of bilateral mumps deafness in whom cochlear implantations (CI) were performed. The age at the onset of hearing loss was 1-9 years. CI surgery was performed within 6 months from the onset of hearing loss in 3 cases and after 9 years in the other case, showing good speech perception in the early intervention cases and a poor outcome after later implantation. Early CI surgery is highly recommended in sudden onset deafness by mumps in childhood.

Macrophage recruitment, but not interleukin 1 beta activation, enhances noise-induced hearing damage.

It has been suggested that macrophages or inflammatory monocytes participate in the pathology of noise-induced hearing loss (NIHL), but it is unclear how extensively these cells contribute to the development of temporary and/or permanent NIHL. To address this question, we used clodronate liposomes to deplete macrophages and monocytes. After clodronate liposome injection, mice were exposed to 4-kHz octave band noise at 121 dB for 4 h. Compared to vehicle-injected controls, clodronate-treated mice exhibited significantly reduced permanent threshold shifts at 4 and 8 kHz and significantly smaller outer hair cell losses in the lower-apical cochlear turn. Following noise exposure, the stria vascularis had significantly more cells expressing the macrophage-specific protein F4/80, and this effect was significantly suppressed by clodronate treatment. These F4/80-positive cells expressed interleukin 1 beta (IL-1ß), which noise exposure activated. However, IL-1ß deficient mice did not exhibit significant resistance to intense noise when compared to wild-type mice. These findings suggest that macrophages that enter the cochlea after noise exposure are involved in NIHL, whereas IL-1ß inhibition does not reverse this cochlear damage. Therefore, macrophages may be a promising therapeutic target in human sensorineural hearing losses such as NIHL.

Prediction of Intraoperative CSF Gusher and Postoperative Facial Nerve Stimulation in Patients With Cochleovestibular Malformations Undergoing Cochlear Implantation Surgery.

OBJECTIVE: To determine parameters in computed tomography (CT) of the temporal bone that would be useful for prediction of cerebrospinal fluid (CSF) gusher during cochlear implantation (CI) surgery and postoperative facial nerve stimulation (FNS) in patients with inner ear malformations. STUDY DESIGN: Retrospective study. SETTING: Tertiary referral center. PATIENTS: Three hundred seventy-five cases who had undergone CI surgery including 54 inner ear malformation cases were analyzed. MAIN OUTCOME MEASURES: The diameters of the cochlea modiolar base and porus of the internal auditory canal (IAC), length of IAC, diameter of the vestibular aqueduct (VA) at the operculum, and presence or absence of the modiolus of the cochlea were evaluated by using CT. RESULTS: CSF gusher occurred in 12 (22%) cases, in whom the diameters of the cochlea modiolar base (2.7 ±â€Š0.6 mm, p < 0.01) and widths of VA (1.5 ±â€Š1.0 mm, p < 0.05) were significantly greater compared with those without gusher. The modiolus was significantly less formed (8%) in cases with gusher compared with those without gusher (p < 0.01). FNS occurred in 10 (19%) cases, and the widths of VA and lengths of IAC were significantly shorter in these cases compared with those without FNS (p < 0.05). CONCLUSION: The absence of the modiolus, larger cochlea modiolar base, and wider VA in CT images were important predictors of CSF gusher during CI surgery. The width of VA was also an important factor in predicting FNS.

Age-related morphological changes in the basement membrane in the stria vascularis of C57BL/6 mice.

Basement membrane anionic sites (BMAS) are involved in the selective transport of electrically charged macromolecules in cochlear capillaries. Using cationic polyethyleneimine (PEI), we examined age-related changes in BMAS in the cochleae of C57BL/6 mice. The mice were grouped according to age as follows: 3 days, 4 weeks, 8 weeks, 6 months, and 12 months. In the right bony labyrinths, widths of the stria vascularis were measured in paraffin-embedded sections using light microscopy. The left bony labyrinths were immersed in a 0.5 % cationic PEI solution and embedded in epoxy resin. Ultrathin sections of the left cochlea were examined using transmission electron microscopy. A significant difference in stria vascularis width was observed between the 4-week-old and 12-month-old mice. The PEI distribution in the capillary and epithelial basement membranes (BMs) of the cochlea was observed. In all animals, PEI particles were evenly distributed in the capillary BM of the spiral ligament and in the subepithelial BM of Reissner's membrane. In the stria vascularis, PEI particles were evenly distributed in the capillary BM in 3-day-old mice. In 4- and 8-week-old mice, PEI particle sizes were markedly lower than those observed in 3-day-old mice. In 6- and 12-month-old mice, PEI particles were hardly detected in the strial capillary BM. In the strial capillary BM in these mice, the laminae rarae externa and interna disappeared, but the lamina densa became larger. We speculated that age-related changes of strial capillary BMAS may affect electrically charged macromolecule transport systems in the stria vascularis of C57BL/6 mice.

Predicting round window niche visibility via the facial recess using high-resolution computed tomography.

OBJECTIVE: To predict round window niche (RWN) visibility using high-resolution computed tomography (HRCT). STUDY DESIGN: Case series with chart review. SETTING: Academic tertiary care center. SUBJECTS AND METHODS: We retrospectively reviewed 70 cochlear implant ears that underwent presurgical axial HRCT with a surgical video recorder. The visibility of the RWN was classified into three types: 17 as invisible or nearly invisible, 22 as partially visible, and 31 as fully visible. Next, we measured the following three radiologic parameters: 1) the angle of the external auditory canal (EAC) relative to the cochlear basal turn, 2) the width of the facial recess, and 3) the relative location of the facial nerve (FN) to the cochlear basal turn. These were compared with the RWN visibility. Subsequently, to predict the RWN visibility, a line was created parallel to the EAC line and along the anterior lateral FN. The location of the line relative to the round window membrane was compared with the RWN view. RESULTS: In cases that had poor RWN visibility, the angle of the posterior canal wall portion of the EAC relative to the cochlear basal turn was significantly smaller and the location of the FN to the cochlear basal turn was closer. The location of the prediction line to the round window membrane highly predicted the RWN view during the surgery. CONCLUSION: The RWN visibility and the preoperative HRCT findings showed a high correlation. Drawing the prediction line is a simple and useful way for preoperatively predicting the RWN visibility in cochlear implant surgery.

Novel repair of stapedial footplate defect associated with recurrent meningitis.

OBJECTIVE: Recurrent meningitis resulting from a partial defect of the stapedial footplate is most frequently treated by complete obliteration of the inner ear. Herein, we report the use of a partial obliteration technique in which the fistula is plugged with a shaped incus. PATIENTS: A 5-year-old girl and a 7-year-old boy who had congenital inner ear malformations both developed recurrent meningitis. High-resolution computed tomography (HRCT) revealed soft tissue opacities between the mastoid air cells and the mesotympanum. Exploratory tympanotomies were performed, revealing cerebrospinal fluid (CSF) leakages from fistulae at the stapes footplate in both patients. INTERVENTIONS: In each case, the vestibule was partially obliterated with temporalis fascia and modified incus remnant. Bone dust and fibrin were also applied. MAIN OUTCOME MEASURES: Recurrence of CSF leakage and patient symptoms. RESULTS: None of the patients exhibited vertigo or dizziness after surgery, and meningitis did not recur during the follow-up period. CONCLUSIONS: Compete obliteration of the inner ear space can be avoided by using this technique, thereby leaving room for future cochlear implantation in addition to reducing direct injury to the vestibular system.

Favorable prognostic factors for long-term postoperative hearing results after canal tympanoplasty for congenital aural stenosis.

OBJECTIVE: We aimed to determine favorable prognostic factors for long-term postoperative hearing results after canal tympanoplasty for congenital aural stenosis (CAS). STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Canal tympanoplasty for CAS was performed in 25 ears. INTERVENTION: Primary repair of CAS. MAIN OUTCOME MEASURES: The influences of the following factors on the success of surgery were assessed by univariate and multivariate logistic regression analyses: modified Jahrsdoerfer grading system total score; age at surgery; patterns of presentation (whether sporadic or syndromic); presence of external auditory canal (EAC) cholesteatoma; presence of ossicular fixation, including the malleus bar; presence of a partial atretic plate; exposure of the facial nerve at the tympanic portion; type of tympanoplasty; and each component of the modified Jahrsdoerfer grading system. RESULTS: The univariate analysis revealed that the absence of EAC cholesteatoma (p = 0.029) and the presence of a partial atretic plate (p = 0.040) were significant predictive factors for favorable hearing prognosis, whereas the multivariate logistic regression analysis showed that an absence of EAC cholesteatoma was the most significant favorable predictive factor (p = 0.011), followed by anterolateral position of the malleus/incus complex with respect to the stapes as the second-most favorable factor (p = 0.021). CONCLUSION: The absence of EAC cholesteatoma and anterolateral position of the malleus/incus complex with respect to the stapes are considered useful in predicting long-term favorable hearing results after canal tympanoplasty for CAS.

A new computed tomography method to identify meningitis-related cochlear ossification and fibrosis before cochlear implantation.

OBJECTIVE: To develop a new method to determine the presence of intracochlear ossification and/or fibrosis in cochlear implantation candidates with bilateral profound deafness following meningitis. STUDY DESIGN: Diagnostic test assessment. SETTING: A university hospital. SUBJECTS AND METHODS: This study involved 15 ears from 13 patients with profound deafness following meningitis who underwent cochlear implantation. These ears showed normal structures, soft tissue, partial bony occlusion, and complete bony occlusion in 4, 3, 2, and 6 ears, respectively. We measured radiodensity in Hounsfield units (HU) using 0.5-mm-thick axial high-resolution computed tomography image slices at 3 different levels in the basal turn, the fenestration, and inferior and ascending segment sites, located along the electrode-insertion path. Pixel-level analysis on the DICOM viewer yielded actual computed tomography values of intracochlear soft tissues by eliminating the partial volume effect. The values were compared with the intraoperative findings. RESULTS: Values for ossification (n = 12) ranged from +547 HU to +1137 HU; for fibrosis (n = 11), from +154 HU to +574 HU; and for fluid (n = 22), from -49 HU to +255 HU. From these values, we developed 2 presets of window width (WW) and window level (WL): (1) WW: 1800, WL: 1100 (200 HU to 2000 HU) and (2) WW: 1500, WL: 1250 (500 HU to 2000 HU). The results using these 2 presets corresponded well to the intraoperative findings. CONCLUSION: Our new method is easy and feasible for preoperative determination of the presence of cochlear ossification and/or fibrosis that develops following meningitis.

Supermicrosurgical reconstruction for congenital aural atresia using a pure skin perforator flap: concept and long-term results.

BACKGROUND: Several surgical methods for creating an external auditory canal have been developed in step with clinical innovation. However, revision surgery is often required to address complications, which include external auditory canal stenosis, lateralization of the tympanic membrane, and chronic recurrent otorrhea. These complications occur frequently within 6 to 12 months after surgery. To decrease the incidence of complications, the authors reconstruct the external auditory canal and tympanic membrane in patients with congenital aural atresia using a free pure skin perforator flap that is as thin as a skin graft. They report their outcomes for hearing acuity and complications over 12 months after the operation. METHODS: The authors performed reconstruction of the external auditory canal and tympanic membrane in nine patients with congenital aural atresia. The flap design was based on a pure skin perforator derived from the groin area in eight patients. The flap was folded into an approximately 1.5×3-cm sac and inserted into the external auditory canal. Anastomosis was performed between the perforator vessels and superficial temporal vessels. RESULTS: All pure skin perforator flaps survived, although one case had partial epidermal necrosis. The audiologic follow-up period ranged from 12 to 24 months (mean, 17 months). The mean pure-tone average was 65.1 dB (range, 53 to 80 dB) preoperatively and improved to 32.4 dB (range, 8 to 53 dB) postoperatively. None of these cases showed any potential complications. CONCLUSION: This flap may therefore reduce complications and help to maintain hearing acuity in the long term. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Current concepts in age-related hearing loss: epidemiology and mechanistic pathways.

Age-related hearing loss (AHL), also known as presbycusis, is a universal feature of mammalian aging and is characterized by a decline of auditory function, such as increased hearing thresholds and poor frequency resolution. The primary pathology of AHL includes the hair cells, stria vascularis, and afferent spiral ganglion neurons as well as the central auditory pathways. A growing body of evidence in animal studies has suggested that cumulative effect of oxidative stress could induce damage to macromolecules such as mitochondrial DNA (mtDNA) and that the resulting accumulation of mtDNA mutations/deletions and decline of mitochondrial function play an important role in inducing apoptosis of the cochlear cells, thereby the development of AHL. Epidemiological studies have demonstrated four categories of risk factors of AHL in humans: cochlear aging, environment such as noise exposure, genetic predisposition, and health co-morbidities such as cigarette smoking and atherosclerosis. Genetic investigation has identified several putative associating genes, including those related to antioxidant defense and atherosclerosis. Exposure to noise is known to induce excess generation of reactive oxygen species (ROS) in the cochlea, and cumulative oxidative stress can be enhanced by relatively hypoxic situations resulting from the impaired homeostasis of cochlear blood supply due to atherosclerosis, which could be accelerated by genetic and co-morbidity factors. Antioxidant defense system may also be influenced by genetic backgrounds. These may explain the large variations of the onset and extent of AHL among elderly subjects. This article is part of a Special Issue entitled "Annual Reviews 2013".