title: Pharyngeal Motor Evoked Potential Monitoring During Skull Base Surgery Predicts Postoperative Recovery from Swallowing Dysfunction.
abstract: OBJECTIVE
  Monitoring pharyngeal motor evoked potential (PhMEP) with a modified endotracheal tube is useful for predicting postoperative swallowing dysfunction. However, the relationship between intraoperative PhMEP findings and recovery from postoperative swallowing dysfunction has not been clarified. The aim of this study was to determine whether PhMEP monitoring predicts swallowing dysfunction not only immediately after surgery but also in the postoperative recovery period.
  
  
  METHODS
  We analyzed PhMEPs in 36 patients during treatment for skull base tumors. Recovery from postoperative swallowing dysfunction was evaluated when oral intake was started postsurgery and drip or tube feeding was discontinued. The correlation between the final to baseline PhMEP ratio and postoperative recovery times from swallowing dysfunction was examined.
  
  
  RESULTS
  The PhMEP ratio significantly correlated with postoperative swallowing function immediately after surgery (P < 0.001). The period before starting oral intake in patients with a PhMEP ratio >50% (mean ± standard deviation [SD], 3.8 ± 4.3 days) was shorter than those with a PhMEP ratio ≤50% (mean ± SD, 14.7 ± 11.8 days; P < 0.01). Drip or tube feeding was removed from patients with a PhMEP ratio >50% significantly earlier (mean ± SD, 13.7 ± 19.2 days) than those with a PhMEP ratio ≤50% (mean ± SD, 38.3 ± 27.3 days; P < 0.05). Both univariate and multivariate analysis showed that only the PhMEP ratio was predictive of early recovery from swallowing dysfunction.
  
  
  CONCLUSIONS
  PhMEP monitoring allowed us to predict not only immediate swallowing dysfunction but also recovery from the dysfunction in the postsurgery period.
authors.affiliation: Department of Neurosurgery, Brain Research Institute, University of Niigata, Niigata-City, Japan. Electronic address: mfuku529@bri.niigata-u.ac.jp.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Fukuda
authors.affiliation: Department of Neurosurgery, Brain Research Institute, University of Niigata, Niigata-City, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Takao
authors.affiliation: Department of Neurosurgery, Brain Research Institute, University of Niigata, Niigata-City, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hiraishi
authors.affiliation: Department of Neurosurgery, Brain Research Institute, University of Niigata, Niigata-City, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Yajima
authors.affiliation: Department of Neurosurgery, Brain Research Institute, University of Niigata, Niigata-City, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Saito
authors.affiliation: Department of Neurosurgery, Brain Research Institute, University of Niigata, Niigata-City, Japan.
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Fujii
mesh_terms: D000328:Adult; D000368:Aged; D003680:Deglutition Disorders / Q000175:diagnosis* / Q000503:physiopathology*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D005930:Glossopharyngeal Nerve / Q000503:physiopathology; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010609:Pharyngeal Muscles / Q000294:innervation*; D011183:Postoperative Complications / Q000175:diagnosis* / Q000503:physiopathology*; D011237:Predictive Value of Tests; D019291:Skull Base / Q000601:surgery; D019292:Skull Base Neoplasms / Q000601:surgery*; D013223:Statistics as Topic; D065908:Transcranial Direct Current Stimulation; D014630:Vagus Nerve / Q000503:physiopathology
keywords: Glossopharyngeal nerve; Pharyngeal motor evoked potential; Skull base tumor; Swallowing dysfunction; Transcranial electrical stimulation; Vagus nerve