2025 Poster Presentations
P364: ANALYSIS OF MANEUVERABILITY AT THE PETROCLIVAL REGION: A CADAVERIC ANATOMICAL STUDY OF THE TRANSCOCHLEAR AND ENDOSCOPIC ENDONASAL TRANSCLIVAL APPROACH
Alejandra Rodas, MD; Leonardo Tariciotti, MD; Youssef M Zohdy, MD; Roberto M Soriano, MD; Edoardo Porto, MD; Jackson R Vuncannon, MD; Juan M Revuelta-Barbero, MD, PhD; Biren K Patel, MD; Emily Barrow, MD; Tomas Garzon-Muvdi, MD; Gustavo Pradilla, MD; C. Arturo Solares, MD; Emory University
Introduction: The petroclival region and cerebellopontine angle represent areas of anatomical complexity at the skull base. An adequate access route must be prioritized, limiting the potential injury of critical neurovascular structures. The transcochlear approach is a lateral corridor that offers suitable exposure and control of structures such as the petrous internal carotid artery. However, this procedure must be carefully indicated due to the functional losses it entails, including hearing loss and, possibly, facial nerve paralysis. The endoscopic endonasal approach, on the other hand, presents the advantage of limiting brain retraction and improving time of recovery.
Method: Four embalmed human cadaveric specimens were used for anatomical dissection. The petroclival region was exposed on each side through the transcochlear and endocopic endonasal transclival approaches. Through imaging-based navigation, stereotactic annotation points were collected. The corridor’s volume was assessed for both the endoscopic and lateral approach. The area of exposure at the ventral aspect of the pons was measured, along with a differentiation of the areas lateral and medial to cranial nerve VI. The length of cranial nerves VI, IX, and X, and basilar artery was determined. Angles of attack were collected for critical neurovascular structures on each of the exposed surgical fields.
Results: An endoscopic endonasal transclival and transcochlear approach were dissected bilaterally on each specimen. The endoscopic endonasal corridor provided greater anteromedial exposure in relation to cranial nerve VI, improving maneuverability for lesions crossing the midline. The transcochlear approach provided greater exposure posterolateral to cranial nerve VI, in addition to exposure of the cerebellopontine angle. Maneuverability around cranial nerve VI at Dorello’s canal was improved through the lateral corridor given its direct trajectory for instrumentation and visualization. Maneuverability around cranial nerves IX and X was also favored by the transcochlear approach.
Conclusion: The endoscopic endonasal approach provides adequate exposure anteromedial to cranial nerve VI, with significantly less bone drilling and anatomy distortion. Lateral corridors should be considered when lesions have considerable posterolateral extension. The transcochlear approach provides adequate exposure laterally, with additional control of the petrous carotid, yet it completely abolishes hearing function and patient selection should be carefully planned.
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