title: Endoscopic endonasal transclival resection of chordomas: operative technique, clinical outcome, and review of the literature.
abstract: OBJECTIVE
  Transcranial approaches to clival chordomas provide a circuitous route to the site of origin of the tumor often involving extensive bone drilling and brain retraction, which places critical neurovascular structures between the surgeon and pathology. For certain chordomas, the endonasal endoscopic transclival approach is a novel minimal access, but it is an equally aggressive alternative providing the most direct route to the tumor epicenter.
  
  
  METHODS
  The authors present a consecutive series of patients undergoing endonasal endoscopic resection of clival chordomas. Extent of resection was determined by postoperative volumetric MR imaging and divided into > 95% and < 95%.
  
  
  RESULTS
  Seven patients underwent 10 operations. Preoperative cranial neuropathies were present in 4. The mean patient age was 52.0 years. The mean tumor volume was 34.9 cm3. Intraoperative lumbar drainage was used in 1 patient, and the tumors extended intradurally in 3. One patient underwent 2 intentionally palliative procedures for subtotal debulking. Greater than 95% resection was achieved in 7 of 8 operations in which radical resection was the goal (87%). All tumors with volumes < 50 cm3 had > 95% resection (p = 0.05). The overall mean follow-up was 18.0 months. Cranial neuropathies resolved in all 3 patients with cranial nerve VI palsies. One patient with recurrent nasopharyngeal chordoma died of disease progression; another experienced 2 recurrences before receiving radiation therapy. All surviving patients remain progression free. There were no intraoperative complications; however, 1 patient developed a pulmonary embolus postoperatively. There were no postoperative CSF leaks.
  
  
  CONCLUSIONS
  The endonasal endoscopic transclival approach represents a less invasive and more direct approach than a transcranial approach to treat certain moderate-sized midline skull base chordomas. Longer follow-up is necessary to determine comparability to transcranial approaches for long-term control. Large tumors with significant extension lateral to the carotid artery may not be suitable for this approach.
authors.affiliation: Department of Neurosurgery, New York Presbyterian Hospital, Weill Medical College of Cornell University, New York, New York, USA.
authors.forename: Justin F
authors.initials: JF
authors.lastname: Fraser
authors.forename: Gurston G
authors.initials: GG
authors.lastname: Nyquist
authors.forename: Nicholas
authors.initials: N
authors.lastname: Moore
authors.forename: Vijay K
authors.initials: VK
authors.lastname: Anand
authors.forename: Theodore H
authors.initials: TH
authors.lastname: Schwartz
mesh_terms: D002817:Chordoma / Q000473:pathology* / Q000601:surgery*; D003388:Cranial Fossa, Posterior / Q000473:pathology* / Q000601:surgery*; D018450:Disease Progression; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D019635:Neurosurgical Procedures / Q000379:methods*; D012888:Skull Neoplasms / Q000473:pathology* / Q000601:surgery*