[Neuroendoscopic Surgery for Intraparenchymal Lesions].

Neuroendoscopic surgery using a tubular retractor system (cylinder) offers a minimally invasive approach for deep-seated intraparenchymal brain lesions. By distributing retraction forces circumferentially, the cylinder enables safe access to deep lesions while minimizing injury to the surrounding brain tissue. If combined with neuroendoscopy, this technique provides bright, close-up visualization even within a narrow surgical corridor, allowing for further reduction in cylinder diameter and surgical invasiveness. Preoperative planning is critical, because the operative field is limited to the cylinder tip. Multimodal imaging, including magnetic resonance imaging, computed tomography angiography, and diffusion tensor imaging, facilitates an accurate understanding of lesion characteristics, surrounding vascular structures, and white matter tracts. Simulation-based trajectory planning and appropriate patient positioning further enhance surgical safety and maneuverability. Intraoperatively, different combined surgical techniques (one or two hands) and operative environments (dry or wet field) can be selected according to lesion consistency, bleeding tendency, and surgical objectives, allowing the cylinder to be applied for biopsy and selected tumor resections. With careful case selection and stepwise technical acquisition, neuroendoscopic cylinder surgery is a valuable option for treating intraparenchymal brain lesions.