Novel Strategies for Expanding the Endoscopic Caudal Access to the Craniovertebral Junction: A Cadaveric Comparative Analysis of Nasofrontal Trephination and Posterior Palatectomy.

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 cm 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.