title: [Experimental study on different power CO2 laser for vocal cord injury].
abstract: OBJECTIVE
  To observe the injury and repair of the subepithelial cordectomy by CO2 laser in different power.
  
  
  METHODS
  Thirty dogs were randomly divided into 5 groups according to different laser power such as A(1 W), B(3 W), C(5 W), D(8 W), E(cold instruments), 6 dogs in each group. Subepithelial cordectomy was performed on the dogs and the tissue damage and wound recovery were observed in different time after operation.
  
  
  RESULTS
  The mucosa reaction in group C, D was heavier than those in group A, B, E, and the wounds healed slowly with visible pathological scars. The densities of fibroblast and blood capillary were determined with optical microscope. It was found that those in group C, D were higher than those in group A, B, E. The difference was statistically significant (average P < 0.05). Observation by electron microscope showed that the injuries were lighter in group A, B, E and there was no significant difference in vocal cord repair process, while the injuries were more serious in group C, D with few elastic fibers in lamina propria and collagen fibers increased significantly after vocal cord repairing.
  
  
  CONCLUSIONS
  The tissue repair after subepithelial cordectomy by CO2 laser with low power (1 - 3 W) was similar to that by cold instrument surgery.
authors.affiliation: Department of Otorhinolaryngology, Gongli Hospital Pudong New Area, Shanghai, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Lu-hong
authors.initials: LH
authors.lastname: Cao
authors.forename: Qun
authors.initials: Q
authors.lastname: Chen
authors.forename: Xiao-ping
authors.initials: XP
authors.lastname: Chen
authors.forename: Wei-hua
authors.initials: WH
authors.lastname: Xu
authors.forename: Qin
authors.initials: Q
authors.lastname: Fang
authors.forename: Jing-fei
authors.initials: JF
authors.lastname: Zhang
authors.forename: Na
authors.initials: N
authors.lastname: Sun
authors.forename: Guang-bin
authors.initials: GB
authors.lastname: Sun
mesh_terms: D000818:Animals; D004285:Dogs; D054020:Lasers, Gas / Q000009:adverse effects*; D014827:Vocal Cords / Q000473:pathology* / Q000528:radiation effects*; D014945:Wound Healing