Complex Anterior Cranio-Vertebral Junction Disorders: Can Endoscopy Expand the Indications of Surgery or Improve the Standard Technique?

Introduction: Extended endoscopic endonasal approaches (EEA) are increasingly being used to address a variety of anterior craniovertebral junction (CVJ) pathologies, including tumors, vascular lesions, irreducible bulbo-medullary compression due to rheumatoid pannus and basilar invagination and inveterate C2 Anderson-D'Alonso type 2 fractures. The nuances of EEA and how could expand the indications and change the standard technique in the surgical approaches to CVJ are illustrated and discussed.

Materials and Methods: During 5 years (from 2009 to 2013) 40 consecutive patients presenting anterior CVJ disorders underwent EEA alone or combined with open approaches at our department. Twenty patients harbored tumors including: 5 ventral foramen magnum / clivus meningiomas, 8 chordomas and 7 metastases. Five patients underwent to a combined anterior transcervical - endoscopic endonasal screw fixation approach for inveterate odontoid fractures. During the same period, the EEA was used in 10 patients with irreducible compression of the brainstem by the odontoid process. An endoscopic endonasal odontoidectomy was performed with preservation of the anterior C1 in all patients. Finally we report a resection of a ventral pontine cavernous malformation via an EEA.

Results: Gross total removal was achieved in all but one meningiomas, in four out of six chordoma, and in three patients harboring metastases. Partial resection with adequate decompression were achieved in all others patients. The most frequent complication was cerebrospinal fluid leak in two patients affected by meningiomas. The radiological follow-up revealed a regular ossification in cases of C2 fractures and no evidence of spinal instability. An adequate bulbar-medullary decompression was achieved in all patients submitted with anterior C1 arch preservation, without postoperative instability and posterior fixation.

Conclusion: The transnasal fully endoscopic technique may represent an interesting alternative to traditional open posterior and posterolateral transcondylar approaches or transoral approach for resection of ventral CVJ tumors. Compared with the transoral approach, EEA also ensures adequate exposure of CVJ avoiding some important complications. Moreover, EEA allows to preserve the integrity of the anterior C1 arch, avoiding cranial settling and posterior fusion with its related risk of subaxial instability.