Although modern multislice CT systems can quickly scan a wide range in fine detail, the high exposure dose and long examination time of CT studies are still important issues. CT is therefore generally considered to be unsuitable for screening. This is particularly true for pediatric patients, who are especially sensitive to radiation, and plain radiography is therefore frequently selected for examination of the temporal bone. We have developed an ultra-low-dose CT imaging method using a 320-row area detector CT (ADCT) scanner that may be suitable for screening for diseases of the ear even in pediatric patients.
Temporal bone specimens were scanned with an ADCT scanner (Aquilion ONE^<TM>, Toshiba Medical Systems, Otawara, Japan) using various scan conditions. Image quality was evaluated, and the optimal scan conditions providing clinically acceptable images at the lowest possible exposure dose were identified. A human-body phantom was then scanned with ADCT using these scan conditions. Plain radiography using the Schu..ller method was also performed for the same phantom to acquire images of the temporal bones bilaterally. The CT and radiographic exposure doses were compared to assess the suitability of our ADCT method for screening.
The gantry of the ADCT scanner includes an X-ray source unit and a detector (area detector) which is several times larger than that used in a conventional CT system. Three-dimensional data can be acquired over a wide range in a single high-speed rotation, making it possible to quickly obtain images in the same temporal phase.
As the results, the optimal scan conditions were found to be tube voltage 100 kV, tube current 10 mA, and exposure time 1.5 s/rot. by 1 rotation. The CTDIVOL (standard dose) was 1.7 mGy, which is 0.7% of the usual value of 243.4 mGy. The maximum skin dose to the head in plain radiography of the temporal bones bilaterally was 2.12 mGy on average. The maximum skin dose to the external ear in CT scanning with the above conditions was 1.59 mGy on average, which was lower than that for the Schüller method. However, the dose in CT scanning was slightly higher at the front and rear.
With our proposed CT imaging method, images are acquired in a very short time, three-dimensional image data is obtained, and the exposure dose is equal to or lower than that of plain radiography. This method is therefore expected to be a useful new tool for morphological screening examinations.

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The aim of this study was to assess objectively the canal wall destruction (CW) of pars flaccida retraction cholesteatoma using computed tomography.
A total of 35 ears were treated surgically for pars flaccida retraction cholesteatoma of the middle ear from 2005 to 2009 at the Otorhinolaryngology Department of Miyazaki University Hospital. The age of the patients ranged from 21 to 84 years (average: 49.3±16.4 years), and the male to female ratio was about 3: 2.
The length of the osseous external acoustic meatus was measured using computed tomography. The anterior tympanic spine was useful as an indicator to measure the CW, we measured the distance between the anterior tympanic spine and outer edge of the epitympanum, and calculated the CW length as a proportion of that of the osseous external acoustic meatus (CW ratio).
The length of the osseous external acoustic meatus was measured: anterior wall: 16.2 mm±1.8 (N=35), posterior wall: 10.4 mm±2.5 (N＝32). The distance between the anterior tympanic spine and outer edge of the epitympanum was 5.6 mm±2.4 (N＝35), showing a significant difference compared to the normal group. The CW ratio was 0.35±0.16 (anterior wall) and 0.55±0.27 (posterior wall), and 8.6% (anterior wall) and 43.8% (posterior wall) of cases that exceeded one-half of the CW ratio.
In 2008, the Committee of Terminology of The Japan Otological Society reported cholesteatoma staging. According to this report, 10.2% of cases were classified into stage III, because canal wall destruction accounted for more than a half of the osseous external acoustic meatus. The results for the CW length as a proportion of that of the anterior wall were equivalent to the outcome of the report released by the Committee of Terminology of The Japan Otological Society in 2008.

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Congenital cholesteatoma, which is characterized by a pearly white mass located medial to an intact tympanic membrane and normal pars tensa and pars flaccida, is increasingly detected at an early age according to the development of medical examination and diagnostic technology. The congenital cholesteatoma develops as a small pearl in the middle ear and eventually grows to involve the ossicles and then the attic and the mastoid, causing variant degrees of destruction and impairment. Therefore, patients with congenital cholesteatoma should be operated on at an early stage. However, a high incidence of persistent eustachian tube dysfunction in the pediatric age group can also lead to reconstructive failure, residual conductive hearing loss attributable to middle ear effusion, and recurrence of cholesteatoma after surgery. Therefore, careful consideration of the timing for an operation is required.
We reported 3 cases of children with congenital cholesteatoma that was resolved spontaneously during the follow-up period, and also reported one case underwent tympanoplasty because of enlargement of the cholesteatoma. The results suggest that careful examination was necessary even in the period before tympanoplasty, and in the cases of which recognized the spontaneous regression of congenital cholesteatoma, we could adopt a "wait and watch" attitude, in the absence of 1) severe infection or bone destruction in the middle ear and 2) the risk to form acquired cholesteatomas, until stable eustachian tube function is achieved.

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Treacher Collins Syndrome, alternatively called mandibulofacial dysostosis, is an autosomal dominant anomaly of the craniofacial development that occurs with an incidence of 1 in 50,000 live births. Approximately 60% of cases possibly arise as a result of mutations. After assessing HRCT images using Jahrsdoerfer's grading scale, we performed tympanoplasty for two siblings with Treacher Collins Syndrome. The use of Jahrsdoerfer's grading scale provides us a great prediction of postoperative hearing prognosis. However, mobility of stapes are not evaluated by the grading system, so that we have to prepare for stapes surgery.

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Two cases of traumatic perilymphatic fistula with pneumolabyrinth are described in this report. While they are cleaning their ears, an ear pick penetrated deeply into the canal by mistake. First case was 49 y.o male who showed vertigo, tinnitus and hearing loss on the left ear. After he blew his nose, he lost earing with pneumolabyrinth. Although he received emergency surgery, his hearing did not recover. Second case was 37 y.o female who showed vertigo, tinnitus and hearing loss on the right ear. Pneumolabyrinth was detected by CT scan but patient recovered from hearing loss completely with conservative treatment. The differences between these two cases were the air location of the pneumolabyrinth and the extent of stapes luxation into the vestibule. The pneumolabyrinth in the first case was in the cochlea and it was only in the vestibule in the second case. MRP (Multiplanar Reconstruction) was useful to evaluate the stapes luxation into the vestibule. An emergency surgery should be performed as soon as possible when MPR shows severe stapes luxation into the vestibule.

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Hemangiomas in the internal auditory canal (IAC) are rare. A 38-year-old man presented with right deafness. He reported no facial weakness or spasm. Examinations revealed a tumor at the right IAC, and surgery was performed by translabyrinthine approach with facial nerve neurinoma as the pre-operative diagnosis. Intraoperative findings showed a vascular tumor of the facial nerve. Difficulty in removing the tumor from the facial nerve resulted in a subtotal resection of the tumor. Histopathological diagnosis was hemangioma. Unlike an acoustic tumor, which is the most common tumor found in the IAC, facial nerve hemangioma may cause facial weakness during early stages. Several mechanisms had been described for the facial weakness, such as a compression or infiltration of the facial nerve and steal phenomenon. Early surgical intervention is recommended, but the methods to preserve facial nerve function are controversial, if the tumor is unable to be resected completely.

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Retrospectively we reviewed facial nerve management for the patients who underwent a removal of cancer in the external auditory canal. Eighteen patients were enrolled for this study. Ten patients had undergone lateral petrosectomy. In seven out of ten patients, facial nerves were kept intact and no facial palsy was noted. In three patients, facial nerve rerouting (1), temporally section and suture (2) were performed. These patients showed permanent partial facial palsy, House-Brackmann grade (H-B) II to III, after the surgery.
Eight patients had suffered from subtotal temporal bone removal. Four out of 8 patients had undergone facial- hypoglossal nerve suture for reconstruction of facial nerve function. These patients showed recovery of facial nerve function to H-B grade III or IV. Rest of four had had no interventions for recovery of nerve function and showed complete palsy after the surgery. However, two patients underwent reconstruction surgery several years after tumor removal and showed partial recovery of facial nerve function to H-B grade III. Complete removals of tumor with sufficient margin was required for the malignant lesions. According to surgical interventions and damages, facial nerve function may have been deteriorated. Although the facial nerve was damaged, appropriate managements for facial nerve including reconstruction surgery or rehabilitation will help recovery of the facial nerve function.

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We sought to characterize the effectiveness of concomitant chemoradiotherapy (CCRT) for patients with squamous cell carcinoma of the ear. We performed a retrospective chart review of 23 patients with cancer of the ear who were provided initial treatment in our hospital from December 2001 to February 2011. As an initial treatment, nineteen out of 21 patients with squamous cell carcinoma were treated by radiation therapy with or without chemotherapy. Five patients with stage I tumors were treated by radiation therapy alone or with oral administration of S1. Two patients with stage II tumor was treated by radiation therapy concomitant with low dose docetaxel. Eleven patients with stage IV tumors and a patient with Stage III tumor were treated by CCRT using the TPF regimen (docetaxel, cisplatin, and 5-fluorouracil). Grade 4 adverse events of patients who received CCRT using the TPF regimen involved the leukopenia in one patient and the neutropenia in three patients. Local recurrences were observed in four patients including three patients with T4 tumors. Five-year disease-specific survival rates for all patients and for patients with T4 tumors were 86.2% and 75%, respectively. These results suggested that CCRT is safe and effective as the first treatment for patients with cancer of the ear.

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Squamous cell carcinoma (SCC) of the temporal bones, similar to maxillary sinus cancer, often invades into surrounding bone structure and thus, resistant to radiotherapy. Retrospective study evaluating the efficacy of surgery followed by radiotherapy for the temporal bone SCC revealed poor outcome of advanced cases more than T3 in Pittsburg category. Then, we started to treat such advances cases with supradose intra-arterial chemotherapy and radiotherapy. The local control rate was 80% whereas the local control rate of the previous treatment with surgery and post-operative irradiation was approximately 40%. There was no severe adverse effects attributable to this treatment. This treatment could be served as a treatment choice for locally advanced temporal bone SCC.

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Explorative surgery is recommended irrespective of patient age, if a physician questions the existence of congenital middle ear cholesteatoma in a patient. We use two different surgical procedures depending on the preoperative computed tomography (CT) findings. If preoperative CT shows pneumatization of tympanic attic and mastoid antrum, we apply the one-time closed method in the first stage. In cases without pneumatization of tympanic attic and mastoid antrum, staged tympanoplasty is selected, and silastic sheeting is used through the tympanic attic and mastoid antrum to the middle ear in the initial operation. If pneumatization can be created from the central tympanic cavity to the mastoid cavity, we might easily be able to detect residual cholesteatoma after surgery with postoperative CT.
We examined 40 patients (40 ears) with congenital cholesteatoma who underwent surgery over the past 10 years. We adopted the staging system proposed by Potsic et al. in 2002. Patients classified as Stage I, III and IV comprised 6, 27 and 7 cases, respectively. There were no Stage II patients. Planned staged tympanoplasty was conducted in 8 of 27 Stage III patients and in all 7 Stage IV patients. We could create pneumatization from the central tympanic cavity to the mastoid cavity in all patients. Residual cholesteatoma was found in 25.9% of Stage III and 71.4% of stage IV patients. The incidence of residual cholesteatoma increased as stage number increased. The rate of successful hearing improvement according to the criteria of the Japan Otological Society was 92% (33 of 36 ears).

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Twenty-three ears of congenital cholesteatoma was investigated. It was revealed that cholesteatoma was located in the tympanic cavity in 7 ears, in the epitympanic cavity or mastoid antrum in 4 ears, and extended from the tympanic cavity to the mastoid antrum in 12 ears. Age of cases ranged from 1 to 42 years old, and there were many cases of children. In ears under 10 years old, the symptom tended to be white mass or otorrhea, and the symptom was hearing loss in all ears over 10 years old. Closed-type cholesteatoma were many in ears under 10 years old, while open-type were many in ears over 10 years old.
In the cases that cholesteatoma is in the blind spot in operative procedure, that cholesteatoma occurs multiple lesion and that cholesteatoma extends to the epitympanic cavity or the mastoid antrum from the tympanic cavity, staged tympanoplasty is performed as a general rule. For the closed-type cholesteatoma confined in the tympanic cavity, extraction from myringotomy is possible, if size of the cholesteatoma is less than one tympanic quadrant and contour of the cholesteatoma can be detected through tympanic membrane. Considered clinical feature of congenital cholesteatoma such as tendency of recurrence and many cases of children, the operation policy should be determined.

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Recently, a staging system for congenital cholesteatoma (CC) developed by Potsic has been applied in several studies. To address the validity of that staging system, we retrospectively reviewed the clinical features and outcomes of 31 patients with CC over the decade from 2001 to 2011, comparing findings with those for a previous decade. The stage of CC was determined using Potsic's staging system, with classification into four stages according to ossicular involvement and mastoid extension. Most of the 7 patients categorized as stage I or II were under 5 years old, and diagnosed incidentally. Conversely, 24 cases of stage III or IV showed a higher prevalence of age >5 years, and complained of otitis media and/or hearing loss. Only 2 of these 24 cases had been diagnosed incidentally.
Regarding the location and morphology of diseases, all stage I or II cases were closed-type masses in the anterosuperior quadrant (ASQ). Conversely, only 8% (2/24) of the stage III or IV cases occupied the ASQ without extending to the posterosuperior quadrant (PSQ), with these 2 patients undergoing surgical removal of ossicles to eradicate the disease extending into the Eustachian tube. Half of the stage III or IV cases showed a predilection not for the ASQ, but rather for the PSQ, and 42% of cases (10/24) involved both ASQ and PSQ. Congenital anomalies of the ossicular chain were observed in three stage III cases.
Consistent with outcomes from a previous decade (from 1986 to 1995) reported by Suetake, stage III was the most dominant group, comprising more than 60% in the present study. Although the prevalence of ASQ-type CC has increased slightly, the prevalence of PSQ type categorized into stage III still exceeds that of the ASQ type reported to be the most dominant in Western countries. Different pathogeneses of CC may exist in Asia and Western countries.

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Clinical features of 59 ears of congenital cholesteatoma were evaluated and the surgical strategy for the disease was discussed. In cases of the tymapanic cavity type, lesion was observed mainly in upper part of the tympanic cavity, especially in the PSQ area. The lesion could be extirpated without mastoidectomy in 28ears. In 9 ears of those cases, transcanal approach with the canal skin incision could be performed. This procedure should be indicated to the cases with small cholesteatoma limited in the mesotympanum without the extension to the supratubal recess, incudo-stapedial joint and tympanic sinus. Mastoidectomy was required in 26 ears. Canal wall up procedure was carried out in all of those cases except an ear. The cases with extension to the attic and mastoid cavity have to be operated with canal wall up mastoidectomy. Cases with petrous type cholesteatoma had inner ear disturbance. Mastoidectomy with or without labyrinthectomy should be indicated for cases with the petrous type. In the cases with intraoperative CSF leakage, the surgical cavity has to be obliterated with abdominal fat. Strict follow up is necessary with MRI scanning especially in such cases. The patients with mastoid type congenital cholestetoma had normal inner ear function, but their bony wall of the lateral semicircular canal was eroded. The fundamental treatment for the mastoid type needs transmastoid surgery with preservation of the labyrinth.

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Vestibular schwannoma (VS) surgery requires deep knowledge and experience for surgeons to accomplish properly. Moreover, due to the recent trend of conservative management favored over aggressive surgery in the treatment of VS, it has become quite difficult for young skull base surgeon to pile up experiences for such surgeries.
I graduated from medical school and started my ENT training in 2003 with a future goal of VS removal by myself, being motivated by my own experience of having received VS surgery (size: 2cm) when I was a medical student. After 5 years training in Tohoku university hospital, as well as other institutes in Japan (one year at a neurosurgery hospital) and in Europe (Gruppo Otologico, Piacenza, Italy), I have now become capable of performing such surgeries, and already achieved more than 30 cases of tumor removal of vestibular schwannomas.
Early exposure to surgical centers under excellent mentors is desirable for otology, neurotology and skull base.

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Objectives: In our previous study, we have indicated that keratinocyte growth factor (KGF) plays an important role in cholesteatoma formation. KGF is a mesenchymal-cell-derived paracrine growth factor that specifically stimulates epithelial cell growth. In this study, we investigated the effects of over-expressed KGF in vivo.
Methods: After anesthetized SD rats Flag-hKGF DNA plasmid driven by a CMV14 promoter was injected into external auditory canal (EAC), and electric pulses were given by an electroporator. The ears with Flag-plasmid driven by a CMV14 promoter injection were used as controls. At 1, 4 and 7 days after injection, 3 rats at each time-point were sacrificed. The paraffin sections were used for H&E and immunostainings.
Results: KGF protein was detected at 1, 4 and 7 days in hKGFcDNA injected specimens, but not in control specimens. The inflammation and keratin accumulations were observed only in KGF cDNA injected ear. Moreover, in contrast to the control specimens, larger numbers of Ki-67-positive cells were detected in KGF cDNA transfected specimens (P<0.0001).
Conclusions: These findings indicated that a single injection of KGF cDNA expressive vector coupled with electroporation induced inflammatory reaction and increased proliferative activity of epithelial cells in EAC, and as results, may possibly induce a cholesteatoma formation.

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Apoptosis is closely associated with cochlear sensory hair cell injury caused by several kinds of ototoxic insults. The proteins involved in apoptosis have been identified; the application of antiapoptotic proteins could prevent the development of diseases resulting in hearing loss. However, this strategy, known as protein therapy, has a limitation; the barrier in the cochlea obstructs the entry of high molecular weight proteins into the cochlear, irrespective of whether the proteins are administered systemically or topically in the tympanic cavity.
To slove this problem, we developed the protein transduction domain (PTD) fusing technique. PTD is a peptide originally derived from the HIV Tat protein. When fused with this peptide, high molecular proteins can effectively penetrate the cell membrane. In this study, we constructed an antiapoptotic protein FNK, originally derived from Bcl-x_L, and fused it with PTD. An in vitro study showed that PTD-FNK significantly attenuated cochlear hair cell (HC) death and reduced kanamycin sulfate (KM)-induced caspase-9 expression. Next, we examined if PTD-FNK could reach the cochlea in vivo. We tagged PTD-FNK with myc to form PTD-myc-FNK and examined its immunoreactivity to the myc antibody. PTD-myc-FNK was diffusely distributed throughout the cochlea on both systemic and topical administration of the protein. The distribution was most prominent in the organ of corti and spiral ganglion cells. Immunoreactivity was observed at 1-3 h after systemic administration and at 1-24 h after topical administration. Thereafter, we examined whether PTD-FNK could attenuate the cochlear damage induced by a combination of KM and ethacrynic acid (EA) in vivo. The PTD-FNK protein, irrespective of systemic or topical administration, significantly attenuated the ototoxic drug-induced ABR threshold shifts and reduced the extent of HC death. Further, systemic PTD-FNK administration significantly attenuated the effect of the ototoxic drug-induced cleavage of PARP.
These findings indicate that PTD-FNK can be successfully delivered to the cochlea, where it can effectively prevent the apoptotic cell death of the cochlear HCs induced by KM, and that protein therapy using the PTD fusing technique is a feasible approach for treating diseases resulting in hearing loss.

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Stereocilia are actin-based mechano-sensory organelles that project from the surface of inner ear hair cells, and necessary for detecting sound and acceleration. Stereocilia in cochlea have long rootlet, which are the densely packed actin filaments that traverse into the actin-rich meshwork of the cuticular plate. But the physiological function of these stereocilia rootlets was not known, and no molecule specifically localized to there has been reported. Here, we report that TRIOBP was immuno-localized to rootlets, and necessary to generate the rootlets. We generated a mouse model (Triobp^Δex8) deficient in two of three isoform classes of TRIOBP. Stereocilia rootlets do not develop in homozygous Triobp^Δex8 mice and direct stiffness measurements revealed that these stereocilia bundles are abnormally flexible. This floppy stereocilia degenerate progressively, causing profound deafness. Electron microscopy of paracrystalline arrays formed in vitro confirmed that purified TRIOBP- 4 was sufficient to bundle actin filaments. TRIOBP- 4 bundled actin filaments are more tightly packed compared to purified espin 3A; an actin-bundling protein present along the length of stereocilia, but not in the rootlets. We conclude that TRIOBP provides the maintenance of and stiffness to hair cell stereocilia bundles, and is a novel actin bundling protein required for formation of the rootlets of these mechanosensing organelles.

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PLF (perilymphatic fistula), defined as an abnormal communication between the inner and middle ear, presents a symptomatology of hearing loss and vestibular disorders that is indistinguishable from a number of other inner ear diseases. The methods for diagnosis remain controversial. We have shown that the protein, Cochlin-tomoprotein (CTP), was selectively detected in the perilymph and established a definite diagnostic test for PLF using CTP as a biochemical marker. We have proven the diagnostic performance of the test to have high reliability.
In the national PLF study group, we are now in the process of revising the Japanese diagnostic criteria which was proposed in 1983 and is ahead of many other countries. We also have established an ELISA system that can detect CTP more accurately and objectively compared with western blot. In this manuscript the summarization of the characteristics of PLF revealed by our CTP detection test is also discussed.

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To circumvent some of the disadvantages of conventional hearing aids such as sound distortion, feedback, and cosmetic factors, implantable hearing devices have been developed. However, these hearing devices also have problems such as insufficient output at high frequencies and inflammation.
In this study, a new subcutaneously implanted bone-conduction hearing aid with an external unit and an internal unit is proposed. The external unit consists of a microphone, a speech processor, and a transmitting coil, which send the sound signals and energy to the internal unit by generating a magnetic field. The internal unit consists of a receiving coil, a driving coil, and a vibrator made of giant magnetostrictive material (GMM), which deforms its body by changing the magnetic field. The internal unit is surgically embedded in the temporal bone under the skin and vibrates the skull when the magnetic flux is applied by the external unit. For the first stage in the development of the new bone-conduction hearing aid, a prototype was made and its fundamental properties were examined.
The GMM vibrator has a good linear response and high output especially at high frequencies. In contrast, the output at low frequencies is relatively lower than that at high frequencies. To enhance the output of the implanted bone-conduction hearing aid at low frequencies is an issue in the future.

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Hair cell loss is one of main causes for sensorineural hearing loss. The lack of the capacity for hair cell regeneration makes difficult to restore hearing in mammals. As an alternative of biological regeneration of hair cells, we have developed an artificial cochlear epithelium, which is capable to generate electricity in response to sound stimuli after implantation into a cochlea. The mechanical tonotopy for sound frequency remaining within the cochlea is utilized for discrimination of sound frequency. A piezoelectric membrane in an artificial cochlear epithelium converts sound vibration to electric signals. In vitro setting, an artificial cochlear epithelium generated electricity in response to sound application. After implantation into a guinea pig cochlea, sound stimuli were transmitted through the external auditory canal to a piezoelectric membrane in a cochlea. The application of sound to the stapes induced electrical output from the implanted artificial cochlear epithelium. These findings indicate the potential of an artificial cochlear epithelium as a novel hearing device.

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