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DOI: 10.1055/a-2565-9342
Novel Strategies for Expanding the Endoscopic Caudal Access to the Craniovertebral Junction: A Cadaveric Comparative Analysis of Nasofrontal Trephination and Posterior Palatectomy
Financial Support There was no financial or funding support for the project.

Abstract
Objectives
Although the endoscopic endonasal approach (EEA) has emerged as a preferred alternative to traditional transoral access for craniovertebral junction (CVJ) surgery, its limited inferior reach beyond the C1 level remains a significant challenge. This study investigates the effectiveness of using a contralateral nasofrontal trephination (CNT) or a posterior palatectomy (PP) to enhance the caudal reach to the CVJ region.
Design
A quantitative cadaveric study.
Setting
Cadaver dissection laboratory.
Participants
A total of 15 adult human cadaveric heads.
Methods
EEA, EEA + PP, and EEA + CNT approaches to the CVJ were performed. Neuronavigation was used for objective measurements quantifying the volume of surgical freedom, surface area of deep exposure, entry point sagittal angle, and inferior reach below the odontoid process.
Main Outcome Measures and Results
EEA + CNT demonstrated superior surgical metrics across all parameters. Surface exposure was significantly greater with EEA + CNT (107.04 cm2) versus EEA + PP (86.26 cm2) and standard EEA (69.78 cm2; p < 0.001). The volume of surgical freedom showed similar superiority with EEA + CNT (60.21 cm3), followed by EEA + PP (34.14 cm3) and EEA (26.13 cm3; p < 0.001). Inferior reach below the odontoid (CNT: 6.35 cm; PP: 2.17 cm; EEA: 0.9 cm; p < 0.0001) and surgical trajectory angle (CNT: 50.1 degrees; PP: 21.4 degrees; EEA: 16.6 degrees; p < 0.0001) demonstrated significant stepwise improvements with each adjunct technique.
Conclusion
Both CNT and PP techniques significantly enhance the surgical corridor of traditional EEA for CVJ access. A CNT afforded superior surgical exposure while maintaining minimal invasiveness. PP offers a viable alternative when external incisions are undesired and lesions are confined within the C2–C3 level.
Keywords
3D photogrammetry - craniovertebral junction - endoscopic endonasal approach - endoscopic endonasal odontoidectomy - multiport endoscopic surgery - nasofrontal trephination - posterior palatectomy - quantitative analysis - skull baseData Availability Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.
This article was selected to receive the Rhoton Award at the 34th North American Skull Base Society Conference in New Orleans, Louisiana, USA, 2025.
Publikationsverlauf
Eingereicht: 16. Januar 2025
Angenommen: 21. März 2025
Accepted Manuscript online:
25. März 2025
Artikel online veröffentlicht:
12. Mai 2025
© 2025. Thieme. All rights reserved.
Georg Thieme Verlag KG
Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany
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