Transpterygoid transmaxillary approach to the mesial temporal lobe: Assessment of surgical routes in between the branches of the trigeminal nerve

AIM: Visual field defects and cognitive deficits continue to pose surgical risk after transcranial selective amygdalohippocampectomy(SAH), and minimizing morbidity remains a problem. Endoscopic endonasal transpterigoid-transmaxillary(EETpTm) approach reduces these risks by accessing temporal pole through the branches of trigeminal nerve and performing SAH through rhinal sulcus and anterior segment of uncus. The objective was to investigate the feasibility of SAH through EETpTm approach. MATERIAL AND METHOD: EETpTm approach was performed and the temporal pole was accessed via V1-V2 and V2-V3 branches of the trigeminal nerve. The temporal horn was entered through rhinal sulcus, entorhinal area, semilunar gyrus and SAH was completed. Fiber dissections were performed on six hemispheres. The extent of SAH was evaluated with CT and MRI scans. RESULTS: EETpTm approach was completed by two-step transnasal drilling of the greater wing of the sphenoid bone(GWS). The resection of the pterygoid plate and tubercle, lower part of GWS was initially drilled to expose the temporal dura between V2-V3. Following inferolateral transposition of infraorbital nerve, upper part of GWS was resected along the V1-V2 corridor. The inferior orbital fissure was then widened for full exposure of intradural surgical corridors between V1-V3. After opening dura, SAH was completed by reaching the temporal horn without damaging of any functional white matter tracts. CONCLUSION: Reaching the mesial temporal region via rhinal sulcus and amygdala by performing EETpTm approach allows for successful completion of SAH. SAH via EETpTm approach may be solid alternative to transsylvian SAH or anterior temporal lobectomy, by preventing functional white matter damage.