title: Influence of superior laryngeal nerve injury on glottal configuration/function of thyroidectomy-induced unilateral vocal fold paralysis.
abstract: OBJECTIVE
  Recurrent laryngeal nerve (RLN) injury may induce unilateral vocal fold paralysis (UVFP). During thyroidectomy, the most common cause of UVFP, the superior laryngeal nerve (SLN), is also at risk of injury. In the literature, the influence of SLN injury on glottal configuration and function in patients with UVFP remains controversial. The present study investigates SLN injury influence on glottal configuration and function in patients with UVFP after thyroidectomy.
  
  
  METHODS
  Prospective controlled study.
  
  
  METHODS
  Tertiary medical center.
  
  
  METHODS
  The SLN and RLN function of 34 patients with UVFP after thyroidectomy was determined by laryngeal electromyography. The subjects were dichotomized into the isolated RLN injury group (n = 26) or the concurrent SLN/RLN injury group (n = 8). We evaluated glottal angle and paralyzed vocal fold shape during inspiration, normalized glottal gap area, and glottal shape during phonation. The glottal function measurements included voice acoustic and aerodynamic analyses and the Voice Handicap Index. The aforementioned parameters of the RLN and concurrent SLN/RLN injury groups were compared.
  
  
  RESULTS
  There were no statistical differences in glottal configuration such as glottal angle, paralyzed vocal fold shape, normalized glottal gap area, and glottal shape between the RLN and concurrent SLN/RLN injury groups. There were also no significant differences in other glottal function analyses including fundamental frequency, mean airflow rate, phonation quotient, maximal phonation time, and Voice Handicap Index.
  
  
  CONCLUSIONS
  In the present study, we did not find any evidence that SLN injury could significantly influence the glottal configuration and function in patients with UVFP.
authors.affiliation: Department of Sensory Organs, ENT Section, Sapienza University of Rome, Rome, Italy Department of Otolaryngology, Taichung Veterans General Hospital, Taichung City, Taiwan.
authors.forename: Armando
authors.initials: A
authors.lastname: De Virgilio
authors.affiliation: Department of Neurology, Taichung Veterans General Hospital, Taichung City, Taiwan.
authors.forename: Ming-Hong
authors.initials: MH
authors.lastname: Chang
authors.affiliation: Department of Otolaryngology, Taichung Veterans General Hospital, Taichung City, Taiwan.
authors.forename: Rong-San
authors.initials: RS
authors.lastname: Jiang
authors.affiliation: Department of Otolaryngology, Taichung Veterans General Hospital, Taichung City, Taiwan.
authors.forename: Ching-Ping
authors.initials: CP
authors.lastname: Wang
authors.affiliation: Department of Otolaryngology, Taichung Veterans General Hospital, Taichung City, Taiwan.
authors.forename: Shang-Heng
authors.initials: SH
authors.lastname: Wu
authors.affiliation: Department of Otolaryngology, Taichung Veterans General Hospital, Taichung City, Taiwan School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Shih-An
authors.initials: SA
authors.lastname: Liu
authors.affiliation: Department of Otolaryngology, Taichung Veterans General Hospital, Taichung City, Taiwan School of Medicine, National Yang-Ming University, Taipei, Taiwan School of Speech Language Pathology & Audiology, Chung-Shan Medical University, Taichung City, Taiwan entccwang@msn.com.
authors.forename: Chen-Chi
authors.initials: CC
authors.lastname: Wang
mesh_terms: D000328:Adult; D000367:Age Factors; D004576:Electromyography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007828:Laryngoscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D010699:Phonation / Q000502:physiology; D011446:Prospective Studies; D061226:Recurrent Laryngeal Nerve Injuries / Q000209:etiology* / Q000503:physiopathology; D018570:Risk Assessment; D012720:Severity of Illness Index; D012737:Sex Factors; D013624:Taiwan; D062606:Tertiary Care Centers; D013965:Thyroidectomy / Q000009:adverse effects* / Q000379:methods; D014826:Vocal Cord Paralysis / Q000209:etiology* / Q000503:physiopathology*
keywords: cricothyroid muscle; glottal configuration; superior laryngeal nerve; thyroidectomy; vocal fold paralysis