Exoscope-endoscope-assisted minimal invasive contralateral interhemispheric approach for a lateral ventricular subependymal giant cell astrocytoma

Abstract

Subependymal giant cell astrocytoma (SEGA) is a slow-growing, WHO grade 1 tumor that often arises near the foramen of Monro within the lateral ventricles and predominantly occurs in patients with tuberous sclerosis complex. Traditionally, transcortical-transventricular and interhemispheric-transcallosal approaches have been established for SEGA resection. In this paper, we present advanced visualization tools such as exoscopes and endoscopes that offer enhanced surgical precision by improving depth perception, illumination, and ergonomics for the resection of SEGA through a minimally invasive contralateral interhemispheric keyhole approach. A 55-yearold lady presented to us with a progressively worsening headache for 1 year. MRI showed a subependymal tumor in the right lateral ventricle, suggestive of SEGA. She was positioned with her head turned to the left. A linear incision was marked across the midline as per the shortest contralateral trajectory in neuronavigation guidance. A left parasagittal keyhole craniotomy was made, and the dura was reflected over the SSS. Under 3D exoscopy, dissection was advanced via an interhemispheric approach, and both pericallosal arteries were identified and safeguarded. Targeted callosotomy was performed after confirmation on navigation. The tumor was grayish, soft, and partly suckable. Following maximal resection with an exoscope, an angled endoscope was introduced to identify hidden slivers of tumor tissue, which were then carefully excised. She improved following surgery, with a post-op scan showing no residual tumor. The histopathology was in favor of SEGA. The exoscopic-endoscopic assisted minimally invasive excision of SEGA demonstrates promise as a safe and effective alternative to traditional microscopy, with particular advantages for deep-seated lateral ventricular tumors where enhanced visualization and improved ergonomics can significantly benefit surgical outcomes.