Endoscopic endonasal study of the maxillary nerve: a new orientation.

Background: Endoscopic endonasal procedures for advanced lesions involving the pterygopalatine fossa (PPF) and its various communications are increasingly performed. The maxillary division of the trigeminal nerve (V2) passes through the foramen rotundum and crosses the upper part of the PPF, with a risk of partial or complete injury during surgery in this complex region. Despite the available knowledge of the sinonasal anatomy, the endoscopic orientation of the V2 remains unclear and requires further analysis from this unique view.
Methods: Using an extended endoscopic approach, the PPF was dissected in 20 sides of 10 adult cadaver heads. The V2 also was followed anteriorly from the trigeminal ganglion, toward the infraorbital canal. The course and the neurovascular relationships of the V2 were studied. High-quality endoscopic images have been produced by coupling the video camera to a digital video recording system.
Results: The endoscopic course and relations of the V2 were carefully described. Important landmarks to identify and avoid injury of the nerve were discussed in relation to this unique view.
Conclusion: This study updates our understanding of the V2 anatomy from an endoscopic perspective. The medial to lateral inclination and drooping of the V2, as well as different relationships of the V2 with the vascular structures are important findings to be taken into consideration while endoscopically addressing related lesions.