title: Prospective validation study of Cernea classification for predicting EMG alterations of the external branch of the superior laryngeal nerve.
abstract: OBJECTIVE
  Cernea classification is applied to describe the external branch of the superior laryngeal nerve (EBSLN). Using intraoperative neural monitoring we evaluated whether or not this classification is useful for predicting which EBSLN subtype has an increased risk of injury.
  
  
  METHODS
  An analysis of 400 EBSLN. The identification of EBSLN was achieved with both cricothyroid muscle twitch and the glottis evoked electromyography response. We defined S1 initial EBSLN stimulation at identification and S2 final nerve stimulation achieved in the most cranial aspect of the nerve exposed above the area of surgical dissection after superior artery ligation.
  
  
  RESULTS
  The mean S1 amplitude acquired was 259+/67 (180-421), 321 +/79 (192-391), 371 +/38 (200-551) μV, respectively, for type 1, 2A, 2B (p = 0.08). The S1 and S2 amplitudes were similar in type 1 (p = 0.3). The S1 and S2 determinations changed significantly in type 2A and 2B (p = 0.04 and 0.03). EBSLN which demonstrated a >25 % decreased amplitude in S2 increased significantly from Type 1 (4.9 %) to Type 2A (11.2 %) and 2B (18 %) (p = 0.01). None of type 1, 2.8 % type 2A and 3 % type 2B showed a loss of EBSLN conductivity. The latency determinations did not vary significantly for any parameter compared.
  
  
  CONCLUSIONS
  The Cernea classification was, therefore, found to predict the risk of EBSLN stress. We identified amplitude differences between S1 and S2 determinations in type 2A and 2B, thus confirming that surgical dissection in these subtypes is, therefore, extremely difficult to perform.
authors.affiliation: 1st Division of Surgery, Department of Surgical Sciences and Human Morphology, Research Center for Endocrine Surgery, University of Insubria (Como-Varese), via Guicciardini 9, 21100, Varese, Italy.
authors.forename: Gianlorenzo
authors.initials: G
authors.lastname: Dionigi
authors.affiliation: Division of Breast and Endocrine Surgery, Department of Surgery, Minimally Invasive Surgery and Robotic Surgery Center, KUMC Thyroid Center, Korea University Anam Hospital, Korea University College of Medicine, Korea University, 73, Inchon-ro, Seongbuk-gu, Seoul, 136-705, South Korea. hoonyubkim@gmail.com.
authors.forename: Hoon Yub
authors.initials: HY
authors.lastname: Kim
authors.affiliation: Division of Thyroid and Parathyroid Endocrine Surgery, Department of Laryngology and Otology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, USA.
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Randolph
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Che-Wei
authors.initials: CW
authors.lastname: Wu
authors.affiliation: Jilin Provincial Key Laboratory of Surgical Translational Medicine, Division of Thyroid Surgery, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Sun
authors.affiliation: Jilin Provincial Key Laboratory of Surgical Translational Medicine, Division of Thyroid Surgery, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Liu
authors.affiliation: Third Chair and Department of General Surgery, Jagiellonian University, Medical College, Krakow, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Barczynski
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Feng-Yu
authors.initials: FY
authors.lastname: Chiang
mesh_terms: D004576:Electromyography / Q000145:classification*; D005931:Glottis / Q000294:innervation / Q000503:physiopathology; D006801:Humans; D007821:Laryngeal Muscles / Q000294:innervation / Q000503:physiopathology; D061224:Laryngeal Nerve Injuries / Q000517:prevention & control; D007823:Laryngeal Nerves / Q000503:physiopathology*; D008026:Ligation; D016343:Monitoring, Intraoperative; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012306:Risk
keywords: Cernea classification; EBSLN; External branch of the superior laryngeal nerve; INMSG; IONM; Intraoperative nerve monitoring; Nerve injury; Neural monitoring study group