Extended Endoscopic Endonasal Approach with or without C1–C2 Anterior Endoscopic Screw Fixation for Cranio-Vertebral Junction Lesions: Lesson Learned and Technical Nuances

Background Extended endoscopic endonasal approaches (EEA) are increasingly being used to address different types of anterior cranio-vertebral junction (aCVJ) diseases, including rheumatoid arthritis-related bulbo-medullary compression, basilar invagination in complex CVJ malformations and non-healed odontoid type II fractures. EEA, eventually supplemented by a variety of anterior endoscopic C1–C2 screw fixation and how these new techniques may help in extending indications or in implementing the conventional techniques, by combined approaches, in aCVJ lesions which require surgical treatment are illustrated and discussed.

Methods From 2009 to July 2017, a total of 36 patients affected by aCVJ disorders underwent EEA alone or combined with conventional surgical approaches at our institution. A combined classical anterior transcervical and endoscopic endonasal C1–C2 screw fixation approach for nonunion of odontoid fractures was used in 12 cases. A fully endoscopic endonasal decompression and C1–C2 fusion was used in five patients affected by complex cranio-vertebral malformations. EEA was also used in 19 patients with irreducible bulbo-medullary junction compression due to a migrated odontoid process and/or retro-periodontoid inflammatory process. Endoscopic endonasal odontoidectomy was performed always sparing the anterior C1 arch, to preserve spine stability or to be used as pivot point for anterior C1–C2 screw fixation and fusion if needed. All patients were followed up by diversified imaging modalities (MRI, CT scan, and dynamic X-ray examinations).

Results An improvement of at least one point in Ranawat or Nurick scales was observed in all cases. Radiologically adequate bulbo-medullary decompression was always achieved. Only two patients developed delayed spine instability, requiring posterior occipito-cervical fixation. Clear bone fusion was always observed when anterior endoscopic C1–C2 screw fixation was used. Two patients had a CSF leaks and two patients suffered from a dehiscence of the mucosal incision with secondary healing confirmed at regular endoscopic outpatient follow-up.

Conclusion The extended transnasal fully endoscopic technique may represent a valid alternative approach to conventional open transcervical, posterolateral, or transoral approaches classically used for aCVJ lesions. The potential advantages over the standard and transoral approaches include less invasiveness, wider and straightforward working angle, enhanced chances of preserving anterior C1 arch, with the possibility for both decompression plus anterior endoscopic C1–C2 fixation/fusion to reduce the risk of cranial settling and the need of posterior C1–C2 or occipito-cervical fusion for spine instability.