title: Outcome of vocal cord function after partial layer resection of the recurrent laryngeal nerve in patients with invasive papillary thyroid cancer.
abstract: BACKGROUND
  The recurrent laryngeal nerve (RLN) may be involved by thyroid cancer even in patients with functioning vocal cords preoperatively. In such cases, we try to preserve the nerve with sharp dissection. As a result of the dissection, the nerve may become thinner than its original thickness. Here we call this operative procedure "partial layer resection of the RLN," if the thickness of the preserved nerve is less than half of its original size. However, there is no report on postoperative vocal cord function after this procedure.
  
  
  METHODS
  We report on 4,585 patients with papillary thyroid cancer who underwent their initial surgery in Kuma Hospital. Among them, 18 patients underwent "partial layer resection of the RLN." We also performed histologic examinations on the RLNs resected because of cancer invasion in 3 other patients.
  
  
  RESULTS
  Postoperatively, 2 patients had functioning vocal cords, 13 had transient vocal cord paralysis, and the remaining 3 had permanent paralysis. Thus, 83% (15/18) of the present patients who underwent partial layer resection of the RLN had functioning vocal cords 1 year after surgery. In patients with transient paralysis, the phonation efficiency index (PEI) 1 year after operation recovered to normal range from the low PEI immediately after operation. Histologic examinations of resected RLN revealed that 78-82% of the cross-section of the nerve is composed of perineural connective tissue surrounding the nerve fibers.
  
  
  CONCLUSIONS
  An unexpectedly high proportion (83%) of the patients who underwent partial layer resection of the RLN achieved functioning vocal cords and nearly normal phonation postoperatively.
authors.affiliation: Department of Surgery, Kuma Hospital, Kobe, Japan. Electronic address: kihara@kuma-h.or.jp.
authors.forename: Minoru
authors.initials: M
authors.lastname: Kihara
authors.affiliation: Department of Surgery, Kuma Hospital, Kobe, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
authors.affiliation: Department of Surgery, Kuma Hospital, Kobe, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Yabuta
authors.affiliation: Department of Surgery, Kuma Hospital, Kobe, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Higashiyama
authors.affiliation: Department of Surgery, Kuma Hospital, Kobe, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Fukushima
authors.affiliation: Department of Surgery, Kuma Hospital, Kobe, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Department of Surgery, Kuma Hospital, Kobe, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Department of Surgery, Kuma Hospital, Kobe, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Miya
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000601:surgery*; D002291:Carcinoma, Papillary; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012009:Recurrent Laryngeal Nerve / Q000601:surgery*; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000601:surgery*; D014827:Vocal Cords / Q000502:physiology*