title: Long-term Follow-up Results of Regeneration Process of Fungiform Taste Buds After Severing the Chorda Tympani Nerve During Middle Ear Surgery.
abstract: OBJECTIVE
  To elucidate the regeneration process of fungiform taste buds after severing the chorda tympani nerve (CTN) by confocal laser scanning microscopy in vivo.
  
  
  METHODS
  In 7 consecutive patients whose CTN was severed during tympanoplasty, an average of 10 fungiform papillae in the midlateral region of the tongue were periodically observed, and the number of taste buds was counted until 12 to 24 months after surgery. Gustatory function was assessed by EGM.
  
  
  RESULTS
  EGM thresholds showed no response within 1 month after surgery in any patient. All taste buds had disappeared until 13 to 71 days after surgery. Regenerated taste buds were first detected 5 to 8 months after surgery in 5 of the 7 patients. EGM thresholds recovered to their preoperative values in 2 patients. In these 2 patients, the number of regenerated taste buds gradually increased in combination with a recovered taste function. However, a time lag existed between taste bud regeneration and taste function recovery. EGM thresholds did not recover in the other 3 patients with regenerated taste buds, suggesting that these taste buds were immature without gustatory function.
  
  
  CONCLUSIONS
  The long-term regeneration process of fungiform taste buds could be clarified using confocal laser scanning microscopy.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Fukui, Fukui, Japan Research and Education Program for Life Science, University of Fukui, Fukui, Japan takehisa@u-fukui.ac.jp.
authors.forename: Takehisa
authors.initials: T
authors.lastname: Saito
authors.affiliation: Research and Education Program for Life Science, University of Fukui, Fukui, Japan Department of Anatomy, Faculty of Medicine, University of Fukui, Japan.
authors.forename: Tetsufumi
authors.initials: T
authors.lastname: Ito
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Fukui, Fukui, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Fukui, Fukui, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Manabe
mesh_terms: D000328:Adult; D000368:Aged; D002814:Chorda Tympani Nerve / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009416:Nerve Regeneration / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*; D013649:Taste / Q000502:physiology*; D013650:Taste Buds / Q000166:cytology / Q000502:physiology*; D013997:Time Factors; D014059:Tongue / Q000294:innervation*; D014433:Tympanoplasty / Q000379:methods*
keywords: chorda tympani nerve; confocal laser scanning microscopy; fungiform taste buds; middle ear surgery; regeneration