title: A novel mouthpiece prevents bite injuries caused by intraoperative transcranial electric motor-evoked potential monitoring.
abstract: Intraoperative transcranial motor-evoked potential monitoring causes contraction of the masseter muscles, which may cause injuries to the oral cavity and damage to the orotracheal tube. We developed a mouthpiece made from vinyl-silicone impression material to prevent these injuries. The purpose of this study was to examine its efficacy and safety.
  
  
  
  Twenty-two patients undergoing spinal surgery under transcranial motor-evoked potential monitoring were fitted with bespoke vinyl-silicone mouthpieces by dentists before surgery. On induction of general anesthesia and orotracheal intubation, the mouthpiece was attached to the upper and lower dental arches. A lateral cervical X-ray was taken at the end of surgery to examine the condition of the orotracheal tube. The incidence of endotracheal tube deformation was compared with an historic control group of 20 patients in whom a conventional gauze bite block had been previously used before induction of the mouthpiece. The oral cavity was examined by a dentist the day before surgery and 3 days postoperatively, and intraoral injuries were recorded.
  
  
  
  No endotracheal tube deformation was found in 22 patients fitted with the new mouthpiece. The incidence of tube deformation (none of 22 patients, 0 %) was significantly lower than in those who had been fitted with the gauze bite block (9 of 20 patients, 45.0 %; p < 0.001). Application of the mouthpiece resulted in no tongue or tooth injuries.
  
  
  
  A novel mouthpiece reduced the incidence of damage to the endotracheal tube caused by intraoperative transcranial motor-evoked potential monitoring.
authors.affiliation: Department of Anesthesiology and Critical Care, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi Minami-ku, Hiroshima, Japan. oshitak@hiroshima-u.ac.jp.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Oshita
authors.affiliation: Department of Anesthesiology and Critical Care, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi Minami-ku, Hiroshima, Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Saeki
authors.affiliation: Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Takayasu
authors.initials: T
authors.lastname: Kubo
authors.affiliation: Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Abekura
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Tanaka
authors.affiliation: Department of Anesthesiology and Critical Care, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi Minami-ku, Hiroshima, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Kawamoto
mesh_terms: D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000009:adverse effects* / Q000295:instrumentation*; D009055:Mouth / Q000293:injuries; D009064:Mouth Protectors; D019635:Neurosurgical Procedures; D013131:Spine / Q000601:surgery; D050781:Transcranial Magnetic Stimulation / Q000009:adverse effects*
keywords: Bite injuries; Mouthpiece; Tc-MEP monitoring