Endoscopic occipital transtentorial transrecess approach for resection of a challenging midbrain-thalamic cavernous malformation: illustrative case.

backgroundMidbrain-thalamic cavernous malformations located adjacent to eloquent neurovascular structures are surgically challenging. The authors evaluated the feasibility and safety of the endoscopic occipital transtentorial transrecess approach (EOTTA) for resection of these lesions. OBSERVATIONS: A 51-year-old woman presented with headache and acute, nonprogressive left hemiparesis. Imaging showed a 2.1 × 1.8 × 1.7-cm lesion at the right thalamus-midbrain junction consistent with a cavernous malformation; preoperative diffusion tensor imaging (DTI) tractograms fused with neuronavigation delineated corticospinal tracts and informed corridor planning. Through use of a lateral decubitus, gravity-assisted approach, a paramedian occipital craniotomy and a tentorial incision were performed 1 cm below the straight sinus to provide a transrecess route into the third ventricle. High-definition endoscopy and neuronavigation guided staged intertumoral debulking and gross-total resection in 110 minutes with 20 mL of blood loss. Postoperative imaging confirmed gross-total resection; the patient recovered full strength and resumed normal activities by 3 months. LESSONS: EOTTA, combined with DTI-guided neuronavigation and endoscopic magnification, can permit safe, effective resection of selected midbrain-thalamic cavernous malformations while minimizing cortical retraction and injury to critical tracts. https://thejns.org/doi/10.3171/CASE25537.