Endoscopic Assistance in Surgery for Insular Lesions: Anatomic Study and Clinical Application.

[BACKGROUND AND OBJECTIVES] Endoscopic assistance during microsurgical procedures offers several advantages, particularly by enhancing visualization of anatomical structures that are difficult to access using a conventional operating microscope. However, its role in insular lesion surgery has not been well established. This study evaluate the anatomic feasibility and clinical utility of endoscopic assistance in the microsurgical management of insular lesions.

[METHODS] A cadaveric study was performed using 6 fixed and 1 fresh human head specimens (14 hemispheres total). Rigid endoscopes with 30° and 45° optics were used to assess the microsurgical anatomy of the insular region. The anatomic findings were applied in 2 clinical cases: a recurrent insular anaplastic astrocytoma and a giant insular cavernoma. In both laboratory and clinical settings, access to the insula was achieved through trans-Sylvian and transopercular approaches, and endoscopic visualization was compared with standard microscopic views.

[RESULTS] Angled endoscopes provided superior visualization of deep surgical corridors, including the entire Sylvian fissure, posterior insular lobe, peri-insular sulcus, and origins of lenticulostriate arteries. The 45° endoscope was particularly effective for subpial dissection beneath M2 branches. Endoscopic assistance enabled enhanced anatomic exposure with minimal brain retraction and without the need for head repositioning. In both clinical cases, endoscope-assisted resection was performed safely, with no postoperative neurological deficits.

[CONCLUSION] Endoscopic assistance improves the visualization of challenging anatomic regions in insular surgery, including structures that are often poorly visualized with standard microscopy. Its use may reduce the need for brain retraction and facilitate safer surgical dissection. Further studies are warranted to clarify its role in routine insular lesions.