Midline Suboccipital Unilateral Trans-Cerebellomedullary Fissure Approach for Clipping of Ruptured VA-PICA Aneurysm: Two-Dimensional Operative Video.

The vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysm poses a technical challenge for microsurgical clipping due to its anatomical complexity, which requires dissection of lower cranial nerves. Endovascular treatment is regarded as a feasible first-line therapeutic option for VA-PICA aneurysm because it has an acceptable aneurysm occlusion rate and is less invasive. However, microsurgical clipping remains an effective treatment option. We present the case of a 62-year-old man who presented with subarachnoid hemorrhage (SAH) due to a ruptured VA-PICA aneurysm. Neuroradiologic examination revealed a 2-3 mm medially pointing left VA-PICA aneurysm with acute obstructive hydrocephalus due to massive SAH in the posterior cranial fossa. As the patient had acute obstructive hydrocephalus and a relatively small aneurysm, we selected clipping over endovascular treatment. Because the aneurysm was located close to the midline and anterolateral to the medulla oblongata, we approached it from the midline. A midline suboccipital craniotomy, C1 laminectomy, and drilling of the left condylar fossa were performed; a unilateral cerebellomedullary fissure opening was added; and the aneurysm was clipped. Postoperative neuroradiologic examinations revealed complete obliteration of the aneurysm. As shown in this video, unilateral cerebellomedullary fissure opening combined with adequate removal of the condylar fossa provides a wide operative field in the cerebellomedullary cistern while avoiding strong retraction of the cerebellum. We believe that this technique makes VA-PICA aneurysm clipping safe and successful. Patient consent was obtained to perform the surgery and to publish the surgical video (Video 1).