Affiliations:
  1. Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan
  2. Department of Otorhinolaryngology, International University of Health and Welfare Mita Hospital, Tokyo, Japan
  3. Department of Plastic and Reconstructive Surgery, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan
  4. Department of Plastic and Reconstructive Surgery, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan
  5. Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan