2026 Poster Presentations
P074: A SINGLE-STAGE COMBINED ANTEROLATERAL-POSTEROLATERAL APPROACH FOR CRANIOVERTEBRAL JUNCTION CHORDOMAS: ANATOMICAL STUDY AND CASE ILLUSTRATION
Veronica de los Santos; Gabriel Heemann, MD; Arianna Fava; Nobuyuki Watanabe; Thibault Passeri; Sébastien Froelich; Hôpital Lariboisière. Paris. Francia
Introduction: The craniovertebral junction (CVJ) is a complex region where stability and mobility coexist. Chordomas in this location are demanding due to their deep midline origin, intricate neurovascular relationships, and bone and soft tissue infiltration into the clivus, occipital condyle, parapharyngeal space, and upper cervical spine, often requiring craniocervical stabilization. However, tumors with both ventral and dorsal extension frequently exceed the limits of a single surgical corridor. Endoscopic endonasal approaches are generally effective for midline lesions above C2, while posterolateral routes are preferred for lateral extensions above C2 and allow fixation during the same stage. In contrast, the anterolateral approach provides access to CVJ lesions extending inferiorly to the upper cervical spine and to the parapharyngeal space, but usually requires a second stage for stabilization. In this context, the management of chordomas with extensive circumferential extension remains difficult, as no conventional approaches provide both adequate exposure and stabilization in a single stage. To overcome this limitation, we propose a combined anterolateral–posterolateral approach, offering circumferential exposure and enabling tumor removal with simultaneous stabilization, with anatomical and clinical illustration.
Methods: Six formalin-fixed, latex-injected adult cadaveric heads underwent a standardized combined anterolateral–posterolateral approach on the right side. The procedure was first performed under the microscope, followed by a second stage with endoscopic assistance, guided by neuronavigation. Pre- and post-dissection CT scans were obtained to quantify drilling and perform measurements. The C1 transverse process served as the integrating landmark to align both routes and define exposure continuity. Quantification was performed on post-dissection CT scans after the microscopic and endoscopic stages: (i) bone removal of the lower clivus, and (ii) circumferential exposure at C1 measured in degrees using the C1 transverse process as the reference. To illustrate clinical applicability, we also present a case of a CVJ chordoma resected through this combined approach.
Results: The combined anterolateral–posterolateral approach provides an extended circumferential exposure of the CVJ, close to three-fourths of the circumference, using the transverse process of C1 as a landmark. Volumetric analysis demonstrated the removal of more than 70% of the lower clivus. Endoscopic assistance expanded the surgical window, improving visualization of contralateral compartments and enabling bone removal. In the illustrative clinical case, this strategy facilitated complete tumor resection and occipitocervical fixation.
Conclusions: The combined anterolateral–posterolateral approach expands the circumferential exposure of the CVJ and represents a single-stage option for CVJ chordomas with both ventral and dorsal extension, enabling resection and stabilization. Using the transverse process of C1 as a central landmark, this study demonstrates the added value of integrating both routes, establishing reproducible reference points that can guide surgical planning and support patient selection. Further anatomical studies are needed to validate these advantages against isolated approaches.
Figure 1: Muscular stage. Figure 2: Bone exposure and neurovascular relationships. Figure 3: Intraoperative exposure. Figure 4: Illustrative case. Preop T2WI MRI (A), preop CT (B), postop T2WI MRI with complete resection (C), CT reconstruction with craniocervical fixation (D).