Step-by-Step Microsurgical Clipping of an Unruptured Right Middle Cerebral Artery Aneurysm Through the Transsylvian Approach: Surgical Video.

Introduction: Microsurgical clipping remains a definitive treatment for selected unruptured middle cerebral artery (MCA) aneurysms, providing durable aneurysm exclusion while preserving the parent artery, perforating vessels, and branch anatomy. This surgical video illustrates the key microsurgical steps for safe clipping of an incidental right MCA aneurysm. Case Report: A 53-year-old man was incidentally diagnosed with an unruptured right middle cerebral artery aneurysm. Microsurgical treatment was performed through a right pterional craniotomy using a transsylvian approach. Following cerebrospinal fluid release and meticulous sylvian fissure dissection, the M1 segment was exposed to obtain proximal vascular control. Temporary clipping of the middle cerebral artery was applied to decrease aneurysm wall tension, allowing circumferential dissection and complete individualization of the aneurysm neck. A permanent clip was then placed under direct microscopic visualization. Continuous intraoperative neurophysiological monitoring was performed, and both somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) remained stable throughout the entire procedure. Indocyanine green videoangiography (ICG-VA) demonstrated complete aneurysm occlusion with preserved patency of the parent artery, distal MCA branches, and perforating vessels. The patient had an uneventful postoperative course without no neurological deficits. Results: Indocyanine green videoangiography confirmed complete aneurysm occlusion with preserved patency of the middle cerebral artery, its branches, and perforating vessels. SSEPs and MEPs remained stable, and the patient had no postoperative neurological deficits. Conclusion: Microsurgical clipping of unruptured MCA aneurysms is a safe and effective procedure when performed with meticulous transsylvian dissection, adequate proximal control, precise clip placement, and continuous neurophysiological monitoring. Stable SSEPs and MEPs throughout the procedure, together with ICG videoangiography confirming complete aneurysm exclusion and vessel patency, provide real-time functional and vascular validation of clip placement, contributing to excellent surgical outcomes.