Amygdalohippocampectomy via the Lateral Extended Transsphenoidal Endoscopic Approach Through the Pterygopalatine Fossa: An Anatomic Study

BACKGROUND: The lateral extended transsphenoidal endoscopic approach (LETEA) is used to remove tumors located lateral to the cavernous segment of the internal carotid artery under direct visual control and provides access to Meckel cave, pterygopalatine fossa, medial part of the middle cranial fossa, and orbit. We describe an extended transsphenoidal approach to the amygdalo-hippocampectomy through the pterygopalatine fossa. METHODS: The LETEA to the middle cranial fossa through the pterygopalatine fossa was studied on 3 injected human cadavers at the Burdenko Neurosurgery Institute in Moscow, Russia. RESULTS: LETEA and trepanation of the greater wing of the sphenoid bone allow access to the medial part of the middle cranial fossa. Medial segments of the temporal lobe (hippocampus and amygdala) and the temporal pole were removed under guidance of the 45 degrees angled endoscope. CONCLUSIONS: LETEA through the pterygopalatine fossa is minimally invasive and provides direct access to the temporal pole and medial part of the temporal lobe. This approach may reduce risk of neurologic deficit and help to avoid cosmetic defects in the frontotemporal region associated with injury to temporal muscle and facial nerve injury as can occur during transcranial approaches. Disadvantages that limit application of LETEA include risk of cerebrospinal fluid leak and skills needed for manipulation in a narrow and deep surgical field with angled 30 degrees and 45 degrees endoscopes.