title: Operative field temperature during transnasal endoscopic cranial base procedures.
abstract: BACKGROUND
  Data regarding the safety of endoscopic skull base exploration are very scarce. With this method, fragile vital structures (cranial nerves, the optic complex, brainstem, hypothalamus or cerebral ventricles) are exposed to direct illumination within a closed space. Also, high-speed drills, cauterization and ultrasonic aspiration deliver a significant load of thermal energy. The aim of this study was to record the temperature close to the structures of the skull base and in the intradural space during the procedures performed using extended endoscopic transnasal approaches.
  
  
  METHODS
  The temperature of the skull base was continuously recorded during six transnasal endoscopic procedures. Implantable copper-constantan thermocouples were inserted: one into the esophagus and another through the nostril to reach the operative field at the skull base.
  
  
  RESULTS
  At the beginning of the procedure, the temperature of the operative field was on average 36.8 °C ± 0.80 °C, i.e. only 1 °C higher than the esophageal temperature. Then it grew continuously during the whole procedure, to eventually reach a level of 42-43 °C at the final stage, whereas the esophageal temperature remained stable. Occasionally, the temperature increased up to 45 °C during cauterization and ultrasonic aspiration, and even up to 62 °C during high-speed drilling.
  
  
  CONCLUSIONS
  Endoscopic skull base surgery is associated with an incessant increase of the temperature of the intraoperative field. The temperature can peak suddenly to levels which can potentially harm neural structures and influence the rate of postoperative complications.
authors.affiliation: Department of Neurosurgery, Medical University of Bialystok, M. Sklodowskiej-Curie 24 A Str., 15-276, Bialystok, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Lyson
authors.forename: Andrzej
authors.initials: A
authors.lastname: Sieskiewicz
authors.forename: Andrzej
authors.initials: A
authors.lastname: Sobolewski
authors.forename: Robert
authors.initials: R
authors.lastname: Rutkowski
authors.forename: Jan
authors.initials: J
authors.lastname: Kochanowicz
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Turek
authors.forename: Anna
authors.initials: A
authors.lastname: Baclawska
authors.forename: Jacek
authors.initials: J
authors.lastname: Krajewski
authors.forename: Marek
authors.initials: M
authors.lastname: Rogowski
authors.forename: Zenon
authors.initials: Z
authors.lastname: Mariak
mesh_terms: D000328:Adult; D004724:Endoscopy / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity; D011183:Postoperative Complications / Q000517:prevention & control; D019291:Skull Base / Q000601:surgery*; D013696:Temperature; D016896:Treatment Outcome