Eiji Yumoto

Kumamoto University, Kumamoto, Kumamoto, Japan

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Publications (233)188.56 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To examine modulation of M-cadherin, a marker for satellite cells (SCs); and MyoD, which may indicate the myogenic activity following recurrent laryngeal nerve (RLN) denervation and immediate reinnervation; and to elucidate the correlation between their modulations and establishment of neuromuscular junctions (NMJs) in the reinnervated rat thyroarytenoid (TA) muscle. Quantitative real-time polymerase chain reaction qPCR and histologic assessment of the TA muscle following RLN transection and anastomosis. Rats were divided into three groups: 1) denervation alone (DNV) (n = 60), 2) denervation with anastomosis (ANS) (n = 60), and 3) sham-operated controls (n = 12). Animals were sacrificed at 3 days and 1, 3, and 5 weeks after treatment. TA muscles harvested from 40 animals from each DNV and ANS group; all of sham group were subjected to qPCR for assessment of the modulation of M-cadherin and MyoD; and the remaining larynges of DNV and ANS group were used for histologic analysis. The expression levels of messenger RNAs (mRNAs) encoding M-cadherin and MyoD in the TA muscle of the DNV group were significantly higher (P < 0.05) than in the control throughout the study period. These mRNA levels in the ANS group were significantly higher (P < 0.05) at ≤ 1 week than in the controls but fell to control levels at ≥ 3 weeks. In the ANS group, recovery of muscle area and NMJs structure occurred by 3 weeks. These data suggested that NMJ formation following reinnervation might prompt recovery of M-cadherin and MyoD mRNA expression to the quiescent level of SCs. N/A. Laryngoscope, 2015. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.
    The Laryngoscope 03/2015; DOI:10.1002/lary.25248 · 2.03 Impact Factor
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    ABSTRACT: To evaluate the long-term efficacy of laryngeal reinnervation via refined nerve-muscle pedicle (NMP) flap implantation combined with arytenoid adduction to treat unilateral vocal fold paralysis (UVFP), employing laryngeal electromyography (LEMG), coronal imaging, and phonatory function assessment. Case series with chart review. University hospital. We retrospectively reviewed 12 UVFP patients who underwent refined NMP implantation with arytenoid adduction. Videostroboscopy, phonatory functional analysis, LEMG, and coronal imaging were performed before and 2 years after surgery. In LEMG analysis, a 4-point scale was employed to grade motor unit (MU) recruitment: 4+ reflected no recruitment, 3+ greatly decreased recruitment, 2+ moderately decreased recruitment, and 1+ mildly decreased activity, associated with less than the full interference pattern. Coronal images were assessed in terms of differences in thickness and the vertical positions of the vocal folds. Phonatory function improved significantly after operation in all patients. In terms of LEMG findings, the preoperative MU recruitment scores were 1+ in no patients, 2+ in 4 patients, 3+ in 1 patient, and 4+ in 7 patients. Postoperative MU recruitment results were 1+ in 6 patients, 2+ in 5 patients, 3+ in 1 patient, and 4+ in no patients. Thinning of the affected fold during phonation was evident preoperatively in 9 of 10 patients. The affected and healthy folds were equal in volume in 4 of 9 patients postoperatively. The LEMG findings and coronal imaging suggest that NMP implantation may have enabled successful reinnervation of the laryngeal muscles of UVFP patients. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.
    Otolaryngology Head and Neck Surgery 02/2015; 152(4). DOI:10.1177/0194599815568945 · 1.72 Impact Factor
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    ABSTRACT: The objective of this study is to evaluate long-term efficacy of refined nerve-muscle pedicle (NMP) flap implantation combined with arytenoid adduction (AA) for treatment of unilateral vocal fold paralysis (UVFP). The authors retrospectively reviewed 33 patients with UVFP who received refined NMP flap implantation with AA and were followed up over a 1-year period. Evaluation of vocal fold vibration (regularity, amplitude, and glottal gap), aerodynamic analysis (maximum phonation time [MPT] and mean airflow rate [MFR]), and perceptual evaluation (Grade and Breathiness) were performed preoperatively and at five different time points (1, 3, 6, 12, and 24 months) postoperatively. All voice parameters improved significantly postoperatively. All parameters except MFR also continued to improve over the course of 24 months. In the videostroboscopic analysis, the parameter for regularity 24 months after surgery was significantly improved compared with that at 1, 3, and 6 months after surgery. There were also significant improvements in amplitude and the glottal gap 24 months after surgery in comparison with values at 3 and 6 months after surgery and 3 months after surgery, respectively. Significant improvement in aerodynamic and perceptual measurements during the follow-up period together with near-normal vocal fold vibration was achieved by delayed reinnervation with refined NMP flap implantation and AA. The combined surgical technique is effective in the treatment of severe breathy dysphonia due to UVFP. Level of evidence 4.
    Archiv für Klinische und Experimentelle Ohren- Nasen- und Kehlkopfheilkunde 12/2014; 272(3). DOI:10.1007/s00405-014-3418-3 · 1.61 Impact Factor
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    ABSTRACT: The molecular mechanisms controlling the proliferation and differentiation of spiral ganglion cells (SGCs) in the inner ear are still largely unknown. TIS21 is a transcriptional cofactor that shows antiproliferative, antiapoptotic, and prodifferentiative effects on neural progenitor cells. To investigate the function of TIS21 during SGC development, we analyzed SGC neurogenesis from embryonic day 13.5 (E13.5) to postnatal day 4 (P4) in Tis21-GFP knock-in mice, in which the protein-encoding exon of the Tis21 gene was replaced by EGFP. Through E13.5 to P4, we found fewer SGCs in homozygous Tis21-GFP knock-in mice than in wild-type mice. Our results suggest that TIS21 is required for development of SGCs. Deleting Tis21 may affect progenitor cells or neuroblasts at the beginning of cochlear-vestibular ganglion formation and would consequently lead to a decrease in the number of SGCs. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
    Neuroscience Letters 10/2014; 584C:265-269. DOI:10.1016/j.neulet.2014.10.001 · 2.06 Impact Factor
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    ABSTRACT: Objective: To establish a rat model with paradoxical vocal fold movement to understand the detailed etiology and physiology of laryngeal synkinesis by evaluating vocal fold movement and by electromyography. Methods: Adult Wistar rats were used. The recurrent laryngeal nerve was transected, anastomosed, and the anastomotic portion was placed in a silicone tube. At 2, 4, and 10 weeks after the treatment (n = 30), we performed laryngoscopy and electromyography. The vocal fold movement was recorded, the hemiglottal area was measured, and the Δarea was calculated by subtracting the area during expiration from that during inhalation. We evaluated the ratio of the Δarea on the treated side to that of the normal side. After laryngoscopy, electromyography of the thyroarytenoid and posterior cricoarytenoid muscles was performed. Results: The mean Δareas were 1.5 ± 3.4%, 2.3 ± 21.5%, and 0.7 ± 31.8% at 2, 4, and 10 weeks after anastomosis, respectively. Eighteen of 18 rats indicated synkinetic reinnervation at 4 and 10 weeks. Regarding vocal fold mobility, 8 of 18 animals showed paradoxical movement, and 5 of 18 exhibited impaired mobility. Conclusion: We have established an animal model of paradoxical movement following recurrent laryngeal nerve injury. This model may be useful in studying laryngeal synkinesis.
    Acta Oto-Laryngologica 10/2014; 134(11). DOI:10.3109/00016489.2014.936625 · 0.99 Impact Factor
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    ABSTRACT: Speech perception in noise is still difficult for cochlear implant (CI) users even with many years of CI use. This study aimed to investigate neurophysiological and behavioral foundations for CI-dependent speech perception in noise. Seventeen post-lingual CI users and twelve age-matched normal hearing adults participated in two experiments. In Experiment 1, CI users' auditory-only word perception in noise (white noise, two-talker babble; at 10 dB SNR) degraded by about 15 %, compared to that in quiet (48 % accuracy). CI users’ auditory-visual word perception was generally better than auditory-only perception. Auditory-visual word perception was degraded under information masking by the two-talker noise (69 % accuracy), compared to that in quiet (77 %). Such degradation was not observed for white noise (77 %), suggesting that the overcoming of information masking is an important issue for CI users’ speech perception improvement. In Experiment 2, event-related cortical potentials were recorded in an auditory oddball task in quiet and noise (white noise only). Similarly to the normal hearing participants, the CI users showed the mismatch negative response (MNR) to deviant speech in quiet, indicating automatic speech detection. In noise, the MNR disappeared in the CI users, and only the good CI performers (above 66 % accuracy) showed P300 (P3) like the normal hearing participants. P3 amplitude in the CI users was positively correlated with speech perception scores. These results suggest that CI users’ difficulty in speech perception in noise is associated with the lack of automatic speech detection indicated by the MNR. Successful performance in noise may begin with attended auditory processing indicated by P3.
    Hearing Research 10/2014; 316. DOI:10.1016/j.heares.2014.08.001 · 2.85 Impact Factor
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    ABSTRACT: Objectives: Evaluate the long-term efficacy of laryngeal reinnervation with refined nerve-muscle pedicle (NMP) flap implantation combined with arytenoid adduction for unilateral vocal fold paralysis (UVFP) using laryngeal electromyography (LEMG), coronal images, and assessment of phonatory function.
    Otolaryngology Head and Neck Surgery 09/2014; 151(1 Suppl):P72-P72. DOI:10.1177/0194599814541627a136 · 1.72 Impact Factor
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    ABSTRACT: Optimal glottal closure as well as symmetrical vocal fold masses and tensions are essential prerequisites for normal voice production. Successful phonosurgery depends on restoring these prerequisites to achieve long-term improvement.
    08/2014; 140(9). DOI:10.1001/jamaoto.2014.1444
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    ABSTRACT: Abstract Conclusions: Over-adduction of the unaffected vocal fold may not compensate vocal function in unilateral vocal fold paralysis (UVFP). Objective: To determine whether over-adduction of the unaffected vocal fold has any impact on vocal function in patients with UVFP. Methods: A total of 101 patients with UVFP who underwent three-dimensional computed tomographic (CT) examination of the larynx served as subjects. Three-dimensional endoscopic images together with coronal images during phonation were produced to evaluate over-adduction of the unaffected fold, posterior glottal gap, and differences in the vertical position and thickness between the vocal folds. Maximum phonation time (MPT) and mean airflow rate (MFR) were measured. Results: In all, 47 patients showed over-adduction. Their MPT and MFR were 4.9 ± 2.9 s and 653 ± 504 ml/s, respectively. The remaining 54 did not show over-adduction. Their MPT and MFR were 4.7 ± 2.7 s and 574 ± 384 ml/s, respectively. There were no significant differences in MPT or MFR between the two groups. Of the 47 patients with over-adduction, 9 showed no posterior glottal gap. However, their vocal function was not significantly different from that of 38 patients with posterior glottal gap or from that of 43 patients without over-adduction and having a posterior glottal gap.
    Acta Oto-Laryngologica 05/2014; DOI:10.3109/00016489.2014.886020 · 0.99 Impact Factor
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    ABSTRACT: To measure the swallowing pressure (SP) of normal subjects using a 2.64-mm-diameter high-resolution manometry (HRM) catheter with 36 circumferential sensors. Repeated measures with subjects serving as controls. Thirty healthy subjects swallowed water at different temperatures and volumes to examine the maximum SP at the velopharynx, meso-hypopharynx, upper esophageal sphincter (UES), and cervical esophagus, and the duration of lowered pressure at the UES. The maximum SP at any location was unaffected by the volume of water, whereas the maximum SP at the UES and cervical esophagus was affected by the temperature. The duration of lowered SP at the UES was significantly prolonged with 10 versus 2 mL of cold water. The pressure curve in males had two peaks (at the velopharynx and UES), whereas that of females had a single peak at the UES. Our data obtained with 2.64-mm HRM demonstrated that as the bolus volume is increased, the duration of lowered SP at the UES is prolonged. The higher maximum SP at the velopharynx in males versus females suggests that there may be a gender difference in pressure at the velopharynx that has not been described previously. This implies that it is necessary to take gender differences into consideration when evaluating the etiology of swallowing dysfunction by examining the SP and SP curve. Moreover, the thinner catheter is less invasive and may contribute to obtaining more physiological measurements. 4 Laryngoscope, 2013.
    The Laryngoscope 03/2014; 124(3). DOI:10.1002/lary.24311 · 2.03 Impact Factor
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    ABSTRACT: To assess laryngeal muscle activity in unilateral vocal fold paralysis (UVFP) patients using laryngeal electromyography (LEMG) and coronal images. Case series with chart review. University hospital. Twenty-one patients diagnosed with UVFP of at least 6 months in duration with paralytic dysphonia, underwent LEMG, phonatory function tests, and coronal imaging. A 4-point scale was used to grade motor unit (MU) recruitment: absent = 4+, greatly decreased = 3+, moderately decreased = 2+, and mildly decreased = 1+. Maximum phonation time (MPT) and mean flow rate (MFR) were employed. Coronal images were assessed for differences in thickness and vertical position of the vocal folds during phonation and inhalation. MU recruitment in thyroarytenoid/lateral cricoarytenoid (TA/LCA) muscle complex results were 1+ for 4 patients, 2+ for 5, 3+ for 6, and 4+ for 6. MPT was positively correlated with MU recruitment. Thinning of the affected fold was evident during phonation in 19 of the 21 subjects. The affected fold was at an equal level with the healthy fold in all 9 subjects with MU recruitment of 1+ and 2+. Eleven of 12 subjects with MU recruitments of 3+ and 4+ showed the affected fold at a higher level than the healthy fold. There was a significant difference between MU recruitment and the vertical position of the affected fold. Synkinetic reinnervation may occur in some cases with UVFP. MU recruitments of TA/LCA muscle complex in UVFP patients may be related to phonatory function and the vertical position of the affected fold.
    Otolaryngology Head and Neck Surgery 02/2014; 149(2 Suppl). DOI:10.1177/0194599814520999 · 1.72 Impact Factor
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    ABSTRACT: To determine the long-term functional outcomes of type II thyroplasty using titanium bridges for adductor spasmodic dysphonia (AdSD) by perceptual analysis using the Voice Handicap Index-10 (VHI-10) and by acoustic analysis. Fifteen patients with AdSD underwent type II thyroplasty using titanium brides between August 2006 and February 2011. VHI-10 scores, a patient-based survey that quantifies a patient's perception of his or her vocal handicap, were determined before and at least 2 years after surgery. Concurrent with theVHI-10 evaluation, acoustic parameters were assessed, including jitter, shimmer, harmonic-to-noise ratio (HNR), standard deviation of F0 (SDF0), and degree of voice breaks (DVB). The average follow-up interval was 30.1 months. No patient had strangulation of the voice, and all were satisfied with the voice postoperatively. In the perceptual analysis, the mean VHI-10 score improved significantly, from 26.7 to 4.1 two years after surgery. All patients had significantly improved each score of three different aspects of VHI-10, representing improved functional, physical, and emotional well-being. All acoustic parameters improved significantly 2 years after surgery. The treatment of AdSD with type II thyroplasty significantly improved the voice-related quality of life and acoustic parameters 2 years after surgery. The results of the study suggest that type II thyroplasty using titanium bridges provides long-term relief of vocal symptoms in patients with AdSD.
    Auris, nasus, larynx 12/2013; DOI:10.1016/j.anl.2013.11.001 · 1.00 Impact Factor
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    ABSTRACT: OBJECTIVES/HYPOTHESIS: To quantitate postdeglutitive residue and determine its association with paralysis duration (≤6 vs. ≥6 months) in patients with idiopathic unilateral vocal fold paralysis (UVFP). STUDY DESIGN: Primary institutional retrospective review. METHODS: Twenty patients (mean age, 72 years) with idiopathic UVFP and 13 patients (mean age, 66 years) with isolated recurrent laryngeal nerve paralysis (RLNP) who underwent videofluoroscopic swallow studies (VFSSs) were included. Vallecular and pyriform sinus (PS) residues in the anteroposterior view were analyzed quantitatively. In both regions, the symmetry of the affected versus nonaffected sides between patients with idiopathic UVFP and RLNP were compared. Residual differences between short- versus long-term paralysis duration in idiopathic UVFP patients alone were also evaluated. RESULTS: The affected PS of the idiopathic group demonstrated significantly increased residue (P = .007) as compared with the nonaffected PS, but with no significant difference with respect to the vallecula (P = .183). There was no significant difference in the RLNP group. When compared with RLNP patients, the idiopathic group showed significantly increased residue on the affected PS (P = .002), but differences in the vallecular residue were nonsignificant. Pharyngeal residue and the duration of paralysis in idiopathic UVFP patients were not significantly different. CONCLUSIONS: Idiopathic UVFP patients were more likely to demonstrate increased residue and asymmetry toward the involved region as compared with RLNP patients, suggesting that nerve involvement in idiopathic UVFP may not be exclusive to the RLN. Laryngoscope, 2013.
    The Laryngoscope 11/2013; 123(11). DOI:10.1002/lary.24132 · 2.03 Impact Factor
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    ABSTRACT: Intubation laryngeal granulomas (ILGs) are a well-known complication of endotracheal intubation. Cases other than ILGs can be categorized as unspecified laryngeal granulomas (ULGs) since their etiologies are often difficult to confirm. We intended to clarify clinical features of both ILGs and ULGs and that anticoagulant medication could cause the formation and delayed healing of ILGs in terms of wound-healing delay. We compared the results of our treatment of ILGs (n = 16) and ULGs (n = 47) treated between 1998 and 2009 to characterize these patients. The clinical course, treatment (medical vs. surgical), indications for surgical resection, treatment outcome, and use of anticoagulants for preexisting disease were reviewed and compared between these two groups. The resolution rate was significantly better in ILGs (p < .05). Five ILGs and seven ULGs were surgically resected. The main reason for resection was airway obstruction and the need for histological assessment, respectively. The use of anticoagulants was significantly higher in ILGs than ULGs (8/16 vs. 4/47, p < .01). The resolution period was significantly longer in the ILGs patients with anticoagulant medication compared to that in the ILGs patients without anticoagulant medication (152 ± 101 days vs. 76 ± 44 days, p < .05). ILGs may have different clinical course from ULGs, especially in terms of the resolution period. Moreover, administration of anticoagulants may deter healing of small injury due to intubation. Patients taking anticoagulants should be managed carefully during the perioperative period to prevent the occurrence of ILGs.
    Archives of Oto-Rhino-Laryngology 10/2013; 271(5). DOI:10.1007/s00405-013-2760-1 · 1.61 Impact Factor
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    ABSTRACT: Objectives: 1) Describe operative procedures to reinnervate the thyroarytenoid muscle (TA) on the paralyzed side using a modified nerve-muscle pedicle (NMP) flap implantation harvested on the contralateral side combined with arytenoid adduction (AA). 2) Assess time-dependent improvement in vocal function during postoperative follow-up.
    Otolaryngology Head and Neck Surgery 08/2013; 149(2 Suppl):P206-P206. DOI:10.1177/0194599813496044a193 · 1.72 Impact Factor
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    ABSTRACT: Although numerous causative genes for hereditary hearing loss have been identified, there are no fundamental treatments for this condition. Herein, we describe a novel potential treatment for genetic hearing loss. Because mutations or deletions in the connexin (Cx) genes are common causes of profound congenital hearing loss in both humans and mice, we investigated whether gene supplementation therapy using the wild-type Cx gene could cure hearing loss. We first generated inner ear-specific connexin 30 (Cx30)-deficient mice via the transuterine transfer of Cx30-targeted short hairpin RNA (shRNA-Cx30) into otocysts. The inner ear-specific Cx30-deficient mice mimicked homozygous Cx30-deficient mice both histologically and physiologically. Subsequently, we cotransfected the shRNA-Cx30 and the wild-type Cx30 gene. The cotransfected mice exhibited Cx30 expression in the cochleae and displayed normal auditory functions. Next, we performed the transuterine transfer of the wild-type Cx30 gene into the otocysts of homozygous Cx30-deficient mice, thereby rescuing the lack of Cx30 expression in the cochleae and restoring auditory functioning. These results demonstrate that supplementation therapy with wild-type genes can restore postnatal auditory functioning. Moreover, this is the first report to show that Cx-related genetic hearing loss is treatable by in vivo gene therapy.Molecular Therapy (2013); doi:10.1038/mt.2013.62.
    Molecular Therapy 04/2013; DOI:10.1038/mt.2013.62 · 6.43 Impact Factor
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    ABSTRACT: OBJECTIVES/HYPOTHESIS: To evaluate the impact of nimodipineon reinnervation of the long-term denervated rat thyroarytenoid (TA) muscle following nerve-muscle pedicle flap (NMP) implantation. STUDY DESIGN: Quantitative histologic and physiologic assessments. METHODS: Using 120 Wistar rats, we performed NMP implantation at different times after transection of the left recurrent laryngeal nerve (RLN). Sixty animals received nimodipine treatment (NIMO [+] group), and the remaining 60 animals received no nimodipine treatment (NIMO [-] group). As a control, an additional 28 animals were subjected only to transection of the left RLN (DNV group). Subgroups were assigned based on the period after RLN transection (0 [immediate], 8, 16, and 32 weeks). In the DNV group, we assessed histologically the muscle area, axons, neuromuscular junctions (NMJs), and myosin heavy chains (MyHC) type IIA and IIB in the TA muscle. In the NIMO (-) and NIMO (+) groups, histologic assessments and evoked electromyography were performed on the TA muscle at 10 weeks post-NMP implantation. RESULTS: In 8-week interval subgroups, the muscle fiber area and the number of NMJs in the NIMO (+) group were significantly greater than in the NIMO (-) group (P < 0.05, each). In the 0-week and 32-week interval subgroups, the muscle fiber subtype changed significantly, from IIA to IIB (P < 0.01 and P < 0.05, respectively); and, at all time-points the muscle fiber area, number of NMJs, and action potentials in the TA muscle tended to be greater in the NIMO (+) group than in the NIMO (-) group. CONCLUSIONS: Nimodipine expedited the effects of NMP implantation on reinnervation of the long-term denervated TA muscle. Laryngoscope, 2012.
    The Laryngoscope 04/2013; 123(4). DOI:10.1002/lary.23698 · 2.03 Impact Factor
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    ABSTRACT: We established an animal model of recurrent laryngeal nerve reinnervation with persistent vocal fold immobility following recurrent laryngeal nerve injury. In 36 rats, the left recurrent laryngeal nerve was transected and the stumps were abutted in a silicone tube with a 1-mm interspace, facilitating regeneration. The mobility of the vocal folds was examined endoscopically 5, 10, and 15 weeks later. Electromyography of the thyroarytenoid muscle was performed. Reinnervation was assessed by means of a quantitative immunohistologic evaluation with anti-neurofilament antibody in the nerve both proximal and distal to the silicone tube. The atrophy of the thyroarytenoid muscle was assessed histologically. We observed that all animals had a fixed left vocal fold throughout the study. The average neurofilament expression in the nerve both distal and proximal to the silicone tube, the muscle area, and the amplitude of the compound muscle action potential recorded from the thyroarytenoid muscle on the treated side increased significantly (p < 0.05) over time, demonstrating regeneration through the silicone tube. Recurrent laryngeal nerve regeneration through a silicone tube produced reinnervation without vocal fold mobility in rats. The efficacy of new laryngeal reinnervation treatments can be assessed with this model.
    The Annals of otology, rhinology, and laryngology 01/2013; 122(1):49-53. DOI:10.1177/000348941312200109 · 1.05 Impact Factor
  • Japan Journal of Logopedics and Phoniatrics 01/2013; 54(1):8-13. DOI:10.5112/jjlp.54.8
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    ABSTRACT: Although the presence of a non-recurrent inferior laryngeal nerve (NRILN) is rare, surgeons occasionally encounter this anomaly during thyroid and parathyroid surgery. It is usually due to anomalous nerve and blood vessel development from the embryonic branchial arches. We recently encountered two patients with NRILN. One represented type 1 branching from the vagus trunk at the level of the inferior thyroid artery, and the other, type 2 branching at the level of the superior pole of the thyroid gland. Avoiding injury to the inferior laryngeal nerve is a major consideration during thyroid and parathyroid surgery. Because in most cases, including our two cases, NRILNs are associated with anomalous origin of the right subclavian artery from the aortic arch, this anomaly can be predicted by imaging procedures. Therefore, surgeons must pay careful attention to the preoperative examination findings in order to reduce the risk of injury of this nerve.
    Practica Otologica, Supplement 01/2013; 137:102-103. DOI:10.5631/jibirinsuppl.137.102

Publication Stats

883 Citations
188.56 Total Impact Points


  • 1999–2015
    • Kumamoto University
      • • Department of Otolaryngology-Head and Neck Surgery
      • • Graduate School of Medical Sciences
      • • School of Medicine
      Kumamoto, Kumamoto, Japan
  • 2012
    • Sohag University
      Sawhāj, Sūhāj, Egypt
  • 2000–2009
    • The Australian Society of Otolaryngology Head & Neck Surgery
      Evans Head, New South Wales, Australia
  • 1988–1998
    • Ehime University
      • • Department of Otolaryngology
      • • School of Medicine
      Matuyama, Ehime, Japan
  • 1995
    • Ehime Prefectural Central Hospital
      Matuyama, Ehime, Japan