2026 Poster Presentations
P176: A NOVEL CORONAL EXTENDED ENDONASAL APPROACH TO THE ANTERIOR CRANIAL FOSSA: PRESERVATION OF THE OLFACTORY NERVE USING A MUCOSAL-OSSEOUS-DURAL-NEURAL FLAP IN AN ANATOMICAL STUDY INSPIRED BY SARCOPHAGUS DOORS
Luis Fernando Santacruz Florez, MD; Karen Cecilia Melecio Rodriguez, MD; Universidad del Valle, Clinica Imbanaco, Santiago de Cali Colombia
OBJECTIVE: The present work aims to demonstrate a new route for the endonasal anterior fossa approach, that avoids sacrificing the first pair, the olfactory nerve. As usually occurs during this type of surgery, given the completeness of the anatomy of this cranial nerve and its apparent lack of eloquence in the patients.
METHODS: A narrative review of the literature was conducted to explore the olfactory nerve in terms of its neuroembryology, neuroanatomy, neurosemiology, and the clinical implications of its injury. In addition, an anatomical study was performed using cadaveric specimens, with a step by step description of techniques to preserve the olfactory nerve and avoid its sacrifice during anterior cranial fossa approaches, such as the transplanum sphenoidale and transcribriform approaches. The cadaveric dissections were complemented by morphometric analysis and the use of three-dimensional (3D) printed biomodels derived from real patients, allowing a more accurate evaluation of anatomical landmarks and surgical corridors.
RESULTS: Our study demonstrated that the first cranial nerve can be preserved in the coronal extended endonasal approach to the anterior cranial fossa, by following the proposed steps and maintaining the mucosal–osseous–neural flap of the olfactory nerve. Neurosemiological evaluation allows documentation of its integrity before and after surgery, confirming that its injury significantly impacts patients’ quality of life when the nerve is sacrificed.
CONCLUSIONS: In extended endonasal approaches to the anterior cranial fossa particularly the transplanum and transcribriform routes, the integrity of the olfactory nerve can and should be preserved. By following the described anatomical steps and using the proposed mucosal osseous neural flap as a safety landmark, safe access to these regions is achievable while minimizing functional compromise.
KEY WORDS: Olfactory nerve, route, preserve, flap.
INTRODUCTION: The craniofacial skeleton arises from both neural crest–derived mesenchyme and paraxial mesoderm, with the skull base distinguished by the passage of neural structures. In the prechordal region, the olfactory nerve (I) traverses the cribriform plate. Unlike other cranial nerves, the olfactory and optic nerves develop as direct extensions of the brain, maintaining meningeal coverings and subarachnoid space, which makes them particularly vulnerable during surgery.
Anatomically and functionally, the olfactory system (rhinencephalon) is essential for sensory integration, survival, and behavior. Its components the olfactory bulb, tract, striae, and associated cortical regions form a mucosa bone neural complex that cannot be separated without functional loss. Therefore, the olfactory nerve should not be regarded as expendable but rather as a critical structure to be preserved in anterior skull base approaches.