Long-term hearing prognosis after vestibular schwannoma surgery with retrolabyrinthine approach.

PURPOSE: The retrolabyrinthine approach is a surgical method designed to preserve hearing after surgery. When paired with intraoperative monitoring and an endoscope, this approach has demonstrated high rates of postoperative hearing preservation. However, the long-term prognosis of hearing preservation after utilizing this approach for vestibular schwannomas remains unexplored. This study aimed to examine the long-term outcomes of preserved hearing, providing insights into the suitability of the retrolabyrinthine approach for hearing preservation surgery. METHODS: This study included 34 patients with preserved hearing after vestibular schwannoma surgery using the retrolabyrinthine approach at a single center. Long-term hearing prognosis and requirement for additional interventions were retrospectively examined. RESULTS: Immediate after post-operative hearing preservation rate was 71.7%. Among the 34 patients with preserved hearing post-vestibular schwannoma surgery, four (11.8%) required additional interventions. Other patients experienced a gradual deterioration in their hearing status, with an approximate 10 dB decline during the 5-year follow-up; however, a serviceable hearing level persisted long after the surgery in these individuals. CONCLUSIONS: This study indicated the rationale for the retrolabyrinthine approach as a hearing preservation surgery for vestibular schwannomas, emphasizing its long-term hearing prognosis.

Natural history of hearing and tumor growth in vestibular schwannoma in neurofibromatosis type 2-related schwannomatosis.

OBJECTIVES: To determine the natural history of hearing loss and tumor volume in patients with untreated neurofibromatosis type 2 (NF2)-related schwannomatosis. Moreover, we statistically examined the factors affecting hearing prognosis. METHODS: This retrospective cohort study was conducted on 37 ears of 24 patients with NF2-related vestibular schwannomatosis followed up without treatment for more than 1 year. We obtained detailed chronological changes in the PTA and tumor volume in each case over time, and the rate of change per year was obtained. Multivariate analysis was also conducted to investigate factors associated with changes in hearing. RESULTS: The average follow-up period was approximately 9 years, and hearing deteriorated at an average rate of approximately 4 dB/year. The rate of maintaining effective hearing decreased from 30 ears (81%) at the first visit to 19 ears (51%) at the final follow-up. The average rate of change in tumor growth for volume was approximately 686.0 mm3/year. This study revealed that most patients with NF2 experienced deterioration in hearing acuity and tumor growth during the natural course. A correlation was observed between an increase in tumor volume and hearing loss (r = 0.686; p < 0.001). CONCLUSIONS: Although the hearing preservation rate in NF2 cases is poor with the current treatment methods, many cases exist in which hearing acuity deteriorates, even during the natural course. Patients with an increased tumor volume during the follow-up period were more likely to experience hearing deterioration. Trial registration number 20140242 (date of registration: 27 October 2014).

A novel auricular prosthesis which incorporates a cartilage conduction hearing aid based on 3D data processing technique: a preclinical evaluation.

PURPOSE: To achieve the challenging goal of simultaneously improving aesthetics and auditory function in the treatment of microtia, we developed an auricular prosthesis incorporating a cartilage conduction hearing aid (APiCHA), which covers a cartilage conduction hearing aid (CC-HA). We evaluated the acoustic characteristics generated by the method of combining these two components using an artificial mastoid and investigated the possibility of clinical translation. METHODS: The first step in creating an APiCHA is to take molds of both the affected and normal auricles and invert the 3D data of the normal auricle to create data for the auricular prostheses. Grooves were then made inside the prosthetic data to fit the affected ear and a CC-HA, and the APiCHA was made of silicone. The acoustic characteristics were measured using an artificial mastoid, and the results were compared between CC-HA alone and with APiCHA. RESULTS: Compared with CC-HA alone, the gain was approximately 2 dB lower at high frequencies from 1 k Hz and higher, and approximately 2 dB higher at approximately 900 Hz when CC-HA was used with APiCHA. For the other frequencies, the acoustic characteristics were almost the same. CONCLUSION: The changes in acoustic characteristics caused by the combined use of APiCHA and CC-HA were minimal and did not pose a clinical problem. The combined use of APiCHA and CC-HA can be considered as a non-invasive and clinically applicable treatment option to achieve both aesthetic and auditory improvements for microtia.

Deficiency of large tumor suppressor kinase 1 causes congenital hearing loss associated with cochlear abnormalities in mice.

Mammalian auditory hair cells are not spontaneously replaced. Their number and coordinated polarization are fairly well-maintained and both these factors might be essential for the cochlear amplifier. Cell cycle regulation has critical roles in regulating appropriate cell size and cell number. However, little is known about the physiological roles of the Hippo pathway, which is one of the most important signaling cascades that regulates cell growth, differentiation, and regenerative capacity in the cochlear sensory epithelium. Herein, we investigated the in vivo role of the large tumor suppressor 1 (LATS1), an essential kinase in the Hippo/yes-associated protein pathway, in the cochlea using the LATS1 knockout mice. LATS1 was expressed in hair cells and supporting cells. It was strongly expressed on the surface of the cuticular plate of the organ of Corti. We found that LATS1 knockout caused congenital hearing loss due to the irregular orientation and slightly reduced number of hair cells, whereas the number of supporting cells remained unchanged. On the surface of the hair cells, the kinocilium and stereocilia were dispersed during and after morphogenesis. However, the expression of the receptor-independent polarity regulators, such as Par3 or Gαi, was not affected. We concluded that LATS1 has an indispensable role in the maturation of mammalian auditory hair cells, but not in the development of the supporting cells, and thus, has a role in the hearing acquisition.

Three cases of otitis media caused by Mycobacterium abscessus subsp. abscessus: Importance of medical treatment and efficacy of surgery.

This study aimed to assess the clinical presentation, antibiotic therapy, surgery, and outcomes in patients with otitis media caused by Mycobacterium abscessus subsp. abscessus and discuss the efficacy of surgery. This is a retrospective case review of three patients diagnosed with otomastoiditis caused by M. abscessus subsp. abscessus. All patients had refractory otorrhea. One patient had granulation tissue in the tympanic membrane. They received medical treatment and underwent surgery. Otorrhea was resolved several months after the initiation of long-term multiantibiotic therapy in all cases. The timing of surgery varied among patients. Before initiating antibiotic therapy, mastoidectomy was performed to achieve definitive diagnosis in two patients, and wound dehiscence developed in these patients. Two patients underwent debridement after the initiation of multiantibiotic therapy. After antibiotic administration, tympanoplasty was performed to improve hearing in one patient. All patients achieved culture negativity after treatment, and no recurrences have been noted. From three cases, it is suggested that the mainstay of treatment for M. abscessus subsp. abscessus is long-term multiantibiotic therapy, and surgery itself may have little effect on achieving ear dryness. Thus, in most patients, drug therapy should be prioritized. Considering postoperative complications, surgery before achieving ear dryness should be avoided, except in emergency cases. In addition, if the diagnosis is not confirmed by repeated bacteriological tests, mastoidectomy should be performed to collect specimens. Tympanoplasty for hearing loss or eardrum perforation is recommended after discontinuation of medications.

Who are good adult candidates for cartilage conduction hearing aids?

PURPOSE: Cartilage conduction hearing aids (CC-HAs) are novel hearing aids using the third hearing pathway of cartilage conduction. We assessed the efficacy of CC-HAs in adult hearing-loss patients who had various anatomical conditions of their ear canal(s) and determined who are good candidates for CC-HAs. METHODS: Patients (n = 37) were categorised into three groups of participants based on ear canal anatomy: (1) canal stenosis; (2) abnormal canal; (3) normal canal. After a 1-month free trial of normal usage, CC-HA-aided and unaided hearing thresholds (43 fitted ears) were determined using standard audiograms, after which participants could choose to purchase the device or not. Group and subgroup purchase rates were calculated along with the purchase reason (or not). Subgroup binary analysis of purchase rates was done according to hearing loss severity (< 70 dB and ≥ 70 dB) of unaided average air conduction (AC) hearing thresholds. RESULTS: CC-HA provided hearing improvements in all frequencies within each group. Overall, 60.47% of participants purchased a CC-HA after the trial. Over 70% participants with canal stenosis purchased CC-HAs, regardless of their AC hearing thresholds (severe vs. mild), and significantly more mild-loss participants in the abnormal canal group purchased their trial CC-HA compared to severe-loss participants (85.71% vs. 20%). CONCLUSION: Adult patients with ear canal stenosis or closure are the best candidates for CC-HAs, regardless of their hearing thresholds. Patients with more severe hearing loss accompanied by ear canal anomalies and patients with normal canal anatomy may not be good candidates.

Management of tinnitus in patients with vestibular schwannoma who underwent surgical resection.

PURPOSE: To evaluate tinnitus and its management in patients with vestibular schwannoma (VS) who underwent surgery, we investigate the effect of surgical approach or residual hearing on tinnitus severity and the effects of intervention for tinnitus including educational counseling, sound therapy using hearing aids (HAs), and medication (selective serotonin reuptake inhibitors, and SSRIs). METHODS: Seventy-one subjects of VS patients who underwent surgery were included. Their tinnitus severity was evaluated using the Japanese version of the Tinnitus Handicap Inventory (THI). The relationships between postoperative THI scores and surgery types or residual hearing levels were examined. We also examined longitudinal changes in THI scores and the efficacy of the intervention. RESULTS: Surgery approach, hearing preservation or hearing loss surgery, and residual hearing levels were not significantly related to the postoperative tinnitus severity. In 71 cases, 45 cases did not require any management for tinnitus. On the contrary, 26 patients had at least one episode of tinnitus distress (THI score was greater than or equal to 18). Educational counseling alone was found to be effective in 17 cases out of the 26 cases, and the remaining 9 cases required more intervention than educational counseling alone. We selected sound therapy with HA for 7 cases and administration of SSRI for 2 cases, which was found to be highly effective in 8 cases. CONCLUSION: Based on the present study, we consider that appropriate management may be possible for tinnitus in the majority of VS patients who underwent surgery.

[Usefulness and Limitation of Thyroglobulin Measurement in Fine Needle Aspirates (FNA-Tg) for Diagnosis of Neck Lymph Node Metastasis from Thyroid Carcinoma].

BACKGROUND: Preoperative diagnosis of lymph node metastasis from thyroid carcinoma is usually confirmed by using fine needle aspiration cytology (FNAC) when thyroid carcinoma is suspected based on the clinical findings. However, the result of FNAC sometimes leads to a false negative, especially in cases of hypocellular lesions such as metastases with cystic change. Thyroglobulin measurement in fine needle aspirates (FNA-Tg) has been shown to be a useful technique to detect the protein specifically secreted by thyroid follicular cells. Elevated FNA-Tg levels in an extra-thyroidal lesion means that the lesion comprises thyroid-originated tissue, most of which suggests the metastasis from thyroid carcinoma. Thus, FNA-Tg is expected to improve the sensitivity of FNAC for the aforementioned purpose. PATIENTS AND METHODS: From 2008 to 2012, 49 extra-thyroidal lesions from 43 patients with thyroid carcinoma were examined using both FNAC and FNA-Tg, followed by surgical resection with a histopathological diagnosis. The results were retrospectively reviewed and analyzed. RESULTS: Among 49 lesions, 47 were metastatic lymph nodes from thyroid carcinoma (46 papillary carcinoma and one follicular carcinoma), one was a metastatic lymph node from submandibular gland adenocarcinoma, and one was an ectopic thyroid gland. In the 47 cases of thyroid carcinoma, the sensitivity of FNAC was 57.4% (27/47), whereas that of FNA-Tg was 76.6% (36/47). When both methods were combined, the sensitivity increased to 93.6% (44/47). Metastasis from submandibular gland adenocarcinoma was considered to be an example of a false positive from FNAC, whereas an ectopic thyroid gland was an FNA-Tg false positive. Three lesions were negative for both FNAC and FNA-Tg, although metastases were suspected by imaging studies and confirmed by histopathological diagnosis, which were consistent with examples of a false negative from both FNAC and FNA-Tg findings. CONCLUSIONS: FNAC reflects whether the lesion has malignant cells, whereas FNA-Tg reflects whether the lesion has thyroid-originated tissue that specifically secrets thyroglobulin. Therefore, FNAC and FNA-Tg are considered to be complementary to each other for the preoperative diagnosis of lymph node metastasis from thyroid carcinoma. FNA-Tg was validated to improve the preoperative diagnostic sensitivity especially when combined with FNAC, however, it is attended with the possibility of a false positive or negative finding, which requires caution in interpretation of the findings.

Nasopharyngeal leiomyomatous hamartoma: case report.

BACKGROUND: Fibroma, neurofibroma, and papilloma are the most commonly encountered benign lesions in the nasopharynx. Hamartomas are non-neoplastic overgrowth of mature/differentiated tissue indigenous to the specific part of the body in which they develop. Most hamartomas are located in the liver, spleen, lungs, and pancreas. However, nasopharyngeal hamartoma is rare. CASE PRESENTATION: We describe here a 77-year-old Japanese woman who presented with a mass arising from the left lateral wall of the nasopharynx. Computed tomography (CT) revealed a soft tissue mass without bony erosion, suggesting that the mass was a benign tumor such as a fibroma. Pathological examination showed that the mass was a leiomyomatous hamartoma. CONCLUSION: To our knowledge, this is the first report of a leiomyomatous hamartoma in the nasopharynx. Although leiomyomatous hamartoma in the nasopharynx is extremely rare, it should be kept in mind during differential diagnosis.

Characteristics of pure tone audiogram in patients with untreated sporadic vestibular schwannoma: Analysis of audiometric shape and interaural differences stratified by age and mode of onset.

OBJECTIVE: Asymmetric sensorineural hearing loss (ASHL) is the most common symptom of sporadic vestibular schwannoma (VS). However, there is still no universally accepted MRI protocol for diagnosing VS. This study identified the characteristics of pure tone audiogram (PTA) in patients with VS. METHODS: We conducted a retrospective chart review of patients diagnosed with sporadic unilateral VS. In the analysis, we focused on the shape and interaural differences of PTA, stratified by the mode of onset and patient age. RESULTS: In total, 390 patients met the inclusion criteria. The U-shaped audiogram showed the highest proportion in patients with the onset of sudden sensorineural hearing loss (SSNHL). In patients with SSNHL, U-shaped audiograms were younger than other audiograms, and 86.7 % of patients under 40 had U-shaped audiograms. Patients with VS were more likely to have interaural differences at higher frequencies than at lower frequencies. Patients with SSNHL had a significantly higher percentage of interaural differences at 500-4000 Hz than those with onset other than SSNHL (non-SSNHL patients). In addition, non-SSNHL patients had a significant trend toward a higher percentage of interaural differences at all frequencies with increasing age. CONCLUSION: MRI screening can be considered in patients with SSNHL with U-shaped audiograms under 40 years of age. In ASHL, not SSNHL, MRI screening can be considered for older patients with interaural differences at wider continuous frequencies. Patients with interaural differences at high frequencies had a higher priority than those with interaural differences at low frequencies as indications for MRI screening for VS.

Binaural hearing aid intervention for a patient with nonserviceable hearing loss after surgery for vestibular schwannoma: A case report.

A vestibular schwannoma is a benign tumor; however, the schwannoma itself and interventions can cause sensorineural hearing loss. Most vestibular schwannomas are unilateral tumors that affect hearing only on one side. Attention has focused on improving the quality of life for patients with unilateral hearing loss and therapeutic interventions to address this issue have been emphasized. Herein, we encountered a patient who was a candidate for hearing preservation surgery based on preoperative findings and had nonserviceable hearing after the surgery, according to the Gardner-Robertson classification. Postoperatively, the patient had decreased listening comprehension and ability to localize sound sources. He was fitted with bilateral hearing aids, and his ability to localize sound sources improved. Although the patient had postoperative nonserviceable hearing on the affected side and age-related hearing loss on the unaffected side, hearing aids in both ears were useful for his daily life. Therefore, the patient was able to maintain a binaural hearing effect and the ability to localize the sound source improved. This report emphasizes the importance of hearing preservation with vestibular schwannomas, and the demand for hearing loss rehabilitation as a postoperative complication can increase, even if hearing loss is nonserviceable.

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.

Imaging of Temporal Bone Mass Lesions: A Pictorial Review.

Tumoral lesions of the temporal bone include benign or malignant tumors and congenital or inflammatory lesions. Temporal bone lesions are difficult to approach. Therefore, making a preoperative diagnosis and considering whether the lesions require treatment are necessary; if they require treatment, then the type of treatment requires consideration. These tumors cannot be observed directly and must be diagnosed based on symptoms and imaging findings. However, the differentiation of temporal bone lesions is difficult because they are rare and large in variety. In this pictorial review, we divided temporal bone lesions by location such as along the facial nerve, along the internal jugular vein, around the endolymphatic sac, in the internal auditory canal/cerebellopontine angle, petrous apex, middle ear, and mastoid, focusing on the imaging findings of temporal bone lesions. Then, we created a diagnostic flowchart that suggested that the systematic separation of imaging findings is useful for differentiation. Although it is necessary to make comprehensive judgments based on the clinical symptoms, patient background, and imaging findings to diagnose temporal bone mass lesions, capturing imaging features can be a useful differentiation method.

Distribution of macrophages in the developing cochlea of the common marmoset, a primate model animal.

Introduction: Macrophages are essential immune cells in the cochlea that contribute to inflammation, tissue repair, and homeostasis. They also play an important role in local cochlear immunity. The developmental immigration and maturation of macrophages in the cochlea have been investigated and are considered essential for normal hearing acquisition. Most of our current knowledge regarding cochlear development is based on rodent models because of the ethical challenges of using human fetal samples for research. However, inter-species differences between rodents and humans have been reported. In this study, we used a primate animal model to investigate the distributions of macrophages in the developing cochlea. The common marmoset (Callithrix jacchus), a small monkey species that inhabits the New World, was used as the model. Methods: We investigated the distribution of macrophages in the developing cochlea of the common marmoset by performing immunohistochemical analyses of cochlear tissue from common marmoset embryos at different development stages. Results: We revealed detailed distribution changes in the macrophages of a primate animal model cochlea. This observation indicates that most of the changes in the general distribution of macrophages were well preserved between rodents and this primate. The distribution changes observed in the common marmoset were also compatible with observations in the human fetus; although, observations in the human fetus are limited. Our observations in this study also revealed several differences between common marmosets and rodents. Conclusion: The time course of immunological development and maturations established in this study will aid in the study of the primate-specific developmental biology of the inner ear. These observations may eventually lead to new therapeutic strategies for hearing loss in humans. In addition, understanding the immunological steady-state of the cochlea may help in the study of age- and genetic-induced hearing loss and in the design of regenerative therapies.

A Case of Vestibular Schwannoma with Deafness Showing Remarkable Hearing Recovery Following Hearing-Preserving Surgery.

Surgery for vestibular schwannoma can be divided into hearing-preserving and nonhearing-preserving surgeries. Hearing-preserving surgery is usually not considered in patients with deafness due to vestibular schwannoma, because hearing is unlikely to improve, and surgery aims to maximize the tumor resection at the expense of hearing. We report an extremely rare case of a 46-year-old man with unilateral profound hearing loss due to a vestibular schwannoma with marked cystic degeneration in the left cistern, which significantly recovered to near-normal hearing levels after hearing-preserving surgery. Hearing loss gradually worsened, and preoperative pure-tone evaluation showed complete hearing loss in the left ear. However, the response to the distortion product otoacoustic emission was preserved, and hearing loss was considered to be retrocochlear. Tumor resection was performed using the retrolabyrinthine approach with continuous monitoring using dorsal cochlear nucleus action potential, auditory brainstem response, and facial nerve function muscle action potential. The cistern portion of the tumor was almost completely resected along with the wall. Postoperatively, the pure-tone threshold on the left side markedly improved. The present case clearly demonstrates the possibility of hearing recovery in patients with retrocochlear hearing loss. We should consider expanding the indications for hearing-preserving surgery.

Development of cochlear spiral ligament fibrocytes of the common marmoset, a nonhuman model animal.

Spiral ligament fibrocytes generate potassium gradients, which hair cells require to convert mechanical sound waves into electrical palsy. Together with the stria vascularis, they regulate endolymph electrolyte homeostasis. Developing spiral ligament fibrocytes and generating endocochlear potential with an appropriate endolymph ion composition are essential for hearing. Understanding spiral ligament fibrocyte development is useful for studying age-related and genetic hearing loss, as well as for regenerative therapy and cochlear immunology. Despite interspecies differences, most studies of cochlear development have been conducted in rodent models due to the difficulty of using human fetal samples. This study investigated the cochlear development of spiral ligament fibrocytes in a small New World monkey species, the common marmoset (Callithrix jacchus). We examined the developmental expression of specific genes in spiral ligament fibrocytes, including those essential for the generation of endolymphatic potential. Our results showed that this animal model of spiral ligament fibrocyte development is similar to that of humans and is a suitable alternative for the analysis of human cochlear development. The time course established in this study will be useful for studying the primate-specific developmental biology of the inner ear, which may lead to novel treatment strategies for human hearing loss.

Bilateral Deafness Due to Relapsing Polychondritis with Semicircular Canal Calcification Treated With Cochlear Implantation: A Case Report.

Relapsing polychondritis (RP) is a rare chronic inflammatory disease characterized by recurrent inflammation of cartilages throughout the body, with treatment-resistant dizziness and hearing loss in 40%-50% of patients with RP. Although rare, severe binaural hearing loss in RP is an indication for cochlear implantation (CI). Therefore, there are only a few reports on CI insertion in cases of RP. This report describes a 68-year-old woman who developed binaural hearing loss due to RP. She was treated with steroids and immunosuppressive drugs; however, her hearing did not improve significantly, and she relied on written communication for conversation. Subsequently, the patient underwent CI in the right ear. The patient showed improvement in speech perception; at 14 months postoperatively, she was able to speak with lipreading, and at 2 years postoperatively, she was able to speak without lipreading. Previous case reports on CI in patients with RP have shown varying degrees of postoperative hearing improvement. Our case demonstrates the effectiveness of CI in improving hearing and speech recognition in patients with RP having semicircular canal calcification. However, previous reports have shown that speech recognition declines 13 years after CI for RP. Therefore, continuous long-term follow-up is necessary.

Vestibular Schwannoma Surgery with Endoscope-Assisted Retrolabyrinthine Approach under Modified Reinforced Continuous Intraoperative Monitoring for Hearing Preservation: Experience of 33 Cases in a Single Center.

Surgery for vestibular schwannoma includes various techniques such as the middle cranial fossa, suboccipital, translabyrinthine, and retrolabyrinthine approaches. The retrolabyrinthine approach does not impair the labyrinth and allows postoperative hearing preservation. Previously, we reported an endoscope-assisted retrolabyrinthine approach under reinforced continuous intraoperative monitoring for preservation of hearing and facial nerve function. However, the hearing preservation rate was relatively low in patients with long-wave V latency in the auditory brainstem response or poor otoacoustic emission response under this approach. Thus, the hearing preservation rate in such patients remains to be improved. To overcome this limitation, we modified the previous approach. In 26 of the 33 consecutive cases (79%) over the last three years, preservation of hearing equivalent to that before surgery or improved hearing was achieved. Postoperative deafness was observed in only two of the 33 cases (6%). According to previous reports, the rate of hearing preservation using the retrolabyrinthine approach is approximately 30-50%. Therefore, we have achieved a higher hearing preservation rate than that previously reported using the endoscopy-assisted retrolabyrinthine approach under reinforced continuous intraoperative monitoring. These improvements in our department are considered to be helpful for hearing preservation.

Intracochlear signal in FIESTA-C and hearings of patients with cerebellopontine angle schwannoma.

BACKGROUND: Hearing loss in patients with cerebellopontine angle (CPA) schwannoma, is thought to be caused by the damage to the cochlea and the cochlear nerve. AIM: This study aimed to examine the relationships between the intracochlear signal in magnetic resonance imaging (MRI) and hearing in patients with CPA schwannoma. MATERIAL AND METHOD: In 79 patients with CPA schwannoma, we retrospectively examined the signal in the cochlea on the affected side was compared with that on the unaffected side to determine signal degradation in fast imaging reagents steady-state acquisition with cycle phases (FIESTA-C) MRI. For hearing evaluation, pure tone audiometry (PTA), speech audiometry, distortion product otoacoustic emissions (DPOAE), and auditory brainstem response (ABR) were used. For each parameter, we examined the differences between the groups with and without signal degradation. RESULTS: In the hearing test results, the I-wave latency of ABR was significantly longer in the group with signal degradation in FIESTA-C (1.84 ± 0.35 msec vs. 2.04 ± 0.37 msec, p = 0.048). There was no statistically significant difference in other tests. CONCLUSION: The MRI signal changes in the cochlear were related to the I-wave latency of ABR and reflected cochlear function. SIGNIFICANCE: We suggested the cochlear signal changes in CPA schwannoma patients related the hearing.