Endoscopic Transanterior Middle Temporal Approach to the Atrium-An Anatomical Feasibility Study.

OBJECTIVE:The atrium is the most common location for masses in the lateral ventricle. However, access to this area is limited owing to its deep location and adjacent eloquent neurovascular structures, such as the choroidal arteries, perisylvian white matter (WM) tracts, and optic radiations. We investigated the feasibility and safety of an endoscopic approach to the atrium via the anterior middle temporal gyrus (MTG). METHODS:Radiological assessment of a minimally invasive surgical trajectory to the atrium was achieved in 10 patients. Surgical simulation to assess the feasibility of our endoscopic approach was performed on 24 cadaveric specimens using a transzygomatic corridor and temporal craniotomy. Preoperative computed tomography was performed to confirm the surgical trajectory using neuronavigation. Using Klinger's method, 5 hemispheres were dissected to assess the relationship of our approach to the WM tracts. RESULTS:The optimal entry angle to reach the atrium through the anterior MTG was related to the temporal horn in the axial plane and to the Sylvian fissure in the sagittal plane. Our entry point in the anterior MTG was 19 ± 1.92 mm from the temporal pole. The transparenchymal distance to atrium was 24.55 ± 4.3 mm. The WM dissections confirmed that our approach did not violate the optic radiations, uncinate fasciculus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, or superior longitudinal fasciculus. CONCLUSION:Our findings have confirmed the feasibility of an anterior endoscopic approach to the atrium through the anterior MTG, with preservation of the functional integrity of the eloquent cortex and WM tracts.