title: Regeneration of the nerves in the aerial cavity with an artificial nerve conduit --reconstruction of chorda tympani nerve gaps-.
abstract: OBJECTIVE
  Due to its anatomical features, the chorda tympani nerve (CTN) is sometimes sacrificed during middle ear surgery, resulting in taste dysfunction. We examined the effect of placing an artificial nerve conduit, a polyglycolic acid (PGA)-collagen tube, across the gap in the section of the resected chorda tympani nerve (CTN) running through the tympanic cavity.
  
  
  METHODS
  The CTN was reconstructed with a PGA-collagen tube in three patients with taste disturbance who underwent CTN resection. To evaluate the effect of the reconstruction procedure on the patients' gustatory function, we measured the patients' electrogustometry (EGM) thresholds. The patients were followed-up for at least two years.
  
  
  RESULTS
  Gustatory function was completely restored in all of the patients after the reconstruction. The patients' EGM thresholds exhibited early improvements within one to two weeks and had returned to their normal ranges within three months. They subsequently remained stable throughout the two-year follow-up period. In a patient who underwent a second surgical procedure, it was found that the PGA-collagen tube used in the first surgical procedure had been absorbed and replaced by new CTN fibers with blood vessels on their surfaces.
  
  
  CONCLUSIONS
  These results suggest that reconstruction of the CTN with an artificial nerve conduit, a PGA-collagen tube, allows functional and morphological regeneration of the nerve and facilitates the recovery of taste function. PGA-collagen tubes might be useful for repairing CTNs that are resected during middle ear surgery. Further research is required to confirm these preliminary results although this is the first report to describe the successful regeneration of a nerve running through an aerial space.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Nara Medical University School of Medicine, Nara, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Yamanaka
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Nara Medical University School of Medicine, Nara, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hosoi
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Nara Medical University School of Medicine, Nara, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Murai
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Nara Medical University School of Medicine, Nara, Japan.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Department of Orthopedic surgery, Inada Hospital, Nara, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Inada
authors.affiliation: Department of Bioartificial Organs. Institute for Frontier Medical Science, Kyoto University, Kyoto, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D000293:Adolescent; D000328:Adult; D002814:Chorda Tympani Nerve / Q000503:physiopathology* / Q000601:surgery*; D003094:Collagen / Q000737:chemistry; D005260:Female; D048091:Guided Tissue Regeneration / Q000379:methods*; D006801:Humans; D007430:Intraoperative Care; D008297:Male; D008875:Middle Aged; D009416:Nerve Regeneration; D011100:Polyglycolic Acid / Q000737:chemistry; D019651:Plastic Surgery Procedures / Q000379:methods*; D055697:Taste Perception; D013652:Taste Threshold
chemical_list: D011100:Polyglycolic Acid; D003094:Collagen