title: Optical Neuronavigation without Rigid Head Fixation During Awake Surgery.
abstract: OBJECTIVE
  Optical neuronavigation without rigid pin fixation of the head may lead to inaccurate results because of the patient's movements during awake surgery. In this study, we report our results using a skull-mounted reference array for optical tracking in patients undergoing awake craniotomy for eloquent gliomas.
  
  
  METHODS
  Between March 2013 and December 2014, 18 consecutive patients (10 men, 8 women) with frontotemporal (n = 16) or frontoparietal (perirolandic; n = 2) lesions underwent awake craniotomy without rigid pin fixation. All patients had a skull-mounted reference array for optical tracking placed on the forehead. Accuracy of navigation was determined with pointer tip deviation measurements on superficial and bony anatomic structures. Good accuracy was defined as a tip deviation <2 mm.
  
  
  RESULTS
  Gross total resection (>98%) was achieved in 7 patients (38%); >90% of tumor was resected in 8 patients (44%). In 3 patients, only subtotal resection or biopsy was performed secondary to stimulation results. In all patients, good accuracy of the optical neuronavigation system could be demonstrated without intraoperative peculiarities or complications. The reference array had to be repositioned because of loosening in 1 patient. Neuronavigation could be reliably applied to support stimulation-based resection.
  
  
  CONCLUSIONS
  A skull-mounted reference array is a simple and safe method for optical neuronavigation tracking without rigid pin fixation of the patient's head.
authors.affiliation: Department of Neurosurgery, Medical University of Innsbruck, Innsbruck, Austria. Electronic address: christian.freyschlag@i-med.ac.at.
authors.forename: Christian F
authors.initials: CF
authors.lastname: Freyschlag
authors.affiliation: Department of Neurosurgery, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Kerschbaumer
authors.affiliation: Department of Neurosurgery, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Eisner
authors.affiliation: Department of Neurosurgery, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pinggera
authors.affiliation: Department of Neurosurgery, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Konstantin R
authors.initials: KR
authors.lastname: Brawanski
authors.affiliation: Department of Neurosurgery, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Ondra
authors.initials: O
authors.lastname: Petr
authors.affiliation: Department of Neurosurgery, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Marlies
authors.initials: M
authors.lastname: Bauer
authors.affiliation: Department of Neuroradiology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Astrid E
authors.initials: AE
authors.lastname: Grams
authors.affiliation: Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bodner
authors.affiliation: Department of Neurosurgery, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Seiz
authors.affiliation: Department of Neurosurgery, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Claudius
authors.initials: C
authors.lastname: Thomé
mesh_terms: D000328:Adult; D000368:Aged; D001931:Brain Mapping / Q000295:instrumentation*; D001932:Brain Neoplasms / Q000601:surgery*; D003399:Craniotomy / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D005625:Frontal Lobe / Q000601:surgery*; D005910:Glioma / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D038361:Neuronavigation / Q000295:instrumentation*; D061848:Optical Imaging / Q000295:instrumentation*; D010296:Parietal Lobe / Q000601:surgery*; D056888:Patient Positioning / Q000295:instrumentation*; D015203:Reproducibility of Results; D012149:Restraint, Physical / Q000295:instrumentation*; D013238:Stereotaxic Techniques / Q000295:instrumentation*; D014851:Wakefulness; D055815:Young Adult
keywords: Awake surgery; Brain mapping; Optic neuronavigation; Rigid pin fixation of the head