title: Recurrent laryngeal nerve safety parameters of the Harmonic Focus during thyroid surgery: Porcine model using continuous monitoring.
abstract: OBJECTIVE
  The Harmonic Focus (HF) is one of the most popular energy-based devices. The aim of this study was to provide recurrent laryngeal nerve (RLN) functional data that define the safety parameters of the HF during thyroidectomy.
  
  
  METHODS
  Prospective porcine model using continuous electrophysiologic monitoring.
  
  
  METHODS
  Ten piglets were used. At varying distances from the RLN, the HF was activated (activation study). The HF was also applied directly on the RLN after activation on sternocleidomastoid muscle for 10 seconds with different cooling times (cooling study).
  
  
  RESULTS
  In the activation study, there was no adverse electromyography (EMG) event at more than 1 mm distance. In the cooling study, there was no adverse EMG event after a 10-second cooling period. When the HF was cooled on the sternocleidomastoid muscle, there was no adverse EMG event after 2 seconds cooling time.
  
  
  CONCLUSIONS
  The safe distance of the HF was 1 mm, and it should be cooled for more than 10 seconds or 2 seconds after cooling on muscle. The HF should be used in a standardized manner to avoid RLN injury.
  
  
  METHODS
  NA.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University.|Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Che-Wei
authors.initials: CW
authors.lastname: Wu
authors.affiliation: Department of Surgery, Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Chai
authors.affiliation: Endocrine Surgery Research Center, Department of Surgical Sciences, University of Insubria, Varese-Como, Varese, Italy.
authors.forename: Gianlorenzo
authors.initials: G
authors.lastname: Dionigi
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University.|Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Feng-Yu
authors.initials: FY
authors.lastname: Chiang
authors.affiliation: Department of Thyroid and Parathyroid Surgery, China-Japan Union Hospital, Jilin University & Jilin Provincial Key Laboratory of Surgical Translational Medicine, Changchun, Jilin, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Thyroid and Parathyroid Surgery, China-Japan Union Hospital, Jilin University & Jilin Provincial Key Laboratory of Surgical Translational Medicine, Changchun, Jilin, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Sun
authors.affiliation: Division of Thyroid and Parathyroid Surgery, Department of Laryngology and Otology, Massachusetts Eye and Ear Infirmary, Harvard Medical School.|Division of Surgical Oncology, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, U.S.A.
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Randolph
authors.affiliation: Division of Head and Neck Endocrine Surgery, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, U.S.A.
authors.forename: Ralph P
authors.initials: RP
authors.lastname: Tufano
authors.affiliation: Department of Surgery, KUMC Thyroid Center, Korea University Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Hoon Yub
authors.initials: HY
authors.lastname: Kim
mesh_terms: D000818:Animals; D004576:Electromyography; D006801:Humans; D016343:Monitoring, Intraoperative / Q000379:methods*; D011446:Prospective Studies; D012009:Recurrent Laryngeal Nerve / Q000502:physiology*; D061226:Recurrent Laryngeal Nerve Injuries / Q000503:physiopathology*; D013552:Swine; D013965:Thyroidectomy / Q000009:adverse effects*
keywords: Harmonic Focus; Recurrent laryngeal nerve; electrophysiologic monitoring; energy-based devices; nerve thermal injury; thyroid surgery