title: Healing process after total cricoidectomy and laryngotracheal reconstruction: endoscopic and histologic evaluation in a canine model.
abstract: OBJECTIVE
  The surgical procedure for subglottic stenosis is technically challenging when the vocal cords are involved and concomitant management for glottic involvement is required. After total cricoidectomy and laryngotracheal anastomosis, T-tube placement for 3 to 6 months is recommended. Bone grafts might shorten this period. We report the histologic and endoscopic changes after total cricoidectomy with or without bone grafts in a canine model to suggest an appropriate period for T-tube placement and the necessity for bone grafts.
  
  
  METHODS
  Ten dogs underwent total cricoidectomy and laryngotracheal anastomosis with or without bone grafts harvested from the ribs. Endoscopic examination was performed monthly, and 1 dog from both groups was humanely killed at 1, 2, 3, 6, and 12 months. The T-tube was removed before death in the dogs killed at 1, 2, and 3 months and at 3 and 6 months in those killed at 6 and 12 months, respectively.
  
  
  RESULTS
  Endoscopically, the glottic opening was in good condition in all dogs, except for 1 that had glottic stenosis. Histologically, active lymphocyte infiltration was observed in dense collagen fibers at the anastomosis at 1 month. At 2 and 3 months, fibroblasts were evident, suggesting active collagen fiber production. At 6 and 12 months, the collagen fibers had become looser. The bone grafts were intact and did not influence the surrounding tissue.
  
  
  CONCLUSIONS
  In the canine model, 6 months of T-tube placement is probably sufficient; however, 3 months of placement might not be. Additionally, no difference was found between the dogs with and without a bone graft.
authors.affiliation: Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan. granada@d3.dion.ne.jp
authors.forename: Kazumichi
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Michitaka
authors.initials: M
authors.lastname: Honda
authors.forename: Tetsurou
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D000714:Anastomosis, Surgical; D000818:Animals; D003413:Cricoid Cartilage / Q000601:surgery*; D004195:Disease Models, Animal; D004285:Dogs; D005931:Glottis / Q000601:surgery*; D006801:Humans; D007828:Laryngoscopy; D007829:Laryngostenosis / Q000601:surgery*; D007830:Larynx / Q000601:surgery*; D011897:Random Allocation; D019651:Plastic Surgery Procedures / Q000379:methods*; D012272:Ribs / Q000637:transplantation; D014132:Trachea / Q000601:surgery*; D014945:Wound Healing / Q000502:physiology*