Comparison between the Classic Endonasal Endoscopical Transcribriform Approach for the Olfactory Grove Meningiomas vs. a Pericribiform “Accordion” Technique Using a Tumor Model in Cadaver Specimens

Background: As we know the Endoscopical transcribriform approach for olfactory grove meningiomas has the disadvantage of damaging the olfactory function. As a novel method we propose a Pericribriform approach sparing the mucosa, fimbria and olfactory tracts with its conforming vessels. The limitations and difficulty of this surgical corridor is described.

Methods: A cadaveric study was performed using a tumor model made of polyurethane foam simulating an olfactory groove meningioma. The tumor-like structure was placed in the olfactory grove region of 6 human cadaver specimens. An endoscopic endonasal approach was performed in all specimens. Three specimens were dissected with a transcribriform approach with exanteration of the entire anterior skull base and the other three specimens were dissected with a pericribriform “Accordion” approach. The differences, difficulty and limitations of visualization for the resection of the tumor were registered and compared.

Results: The traditional endoscopic endonasal approach allowed a great exposure of the tumors from the frontal sinus to the sella in the sagittal plane and laterally to the mid-orbital level bilaterally. The pericribriform “Accordion” technique implies the preservation of the cribriform plate with resection of the bone around it. Crista Galli is removed and the dura is opened in the midline with preservation of the septal mucosa bilaterally. The anterior skull base is opened as an “Accordion” as the structures are retracted laterally. The visualization of this method was restricted on the laterality of the tumor with great antero-posterior exposure.

Conclusion: The surgical corridor proposed has limitations on the visualization and maneuverability of the endoscopical instruments particularly at very lateral extensions of the tumor making it harder for resection of large tumors. However, it seems to be a feasible method of reaching the central aspect of the anterior skull base at the level of the cribriform plate without damaging the olfactory system. Further clinical studies should be performed to evaluate the real function outcome of the novel technique.