Microsurgical Resection of a Medullary Cavernous Malformation via the Far-Lateral Approach in the Presence of an Arcuate Foramen.

Abstract

Background: Approximately 14% of cavernous malformations (CMs) occur in the medulla oblongata, where their proximity to vital neural structures makes surgical intervention challenging. Anatomical variations, such as an arcuate foramen (AF), a bony canal that encases the vertebral artery (VA), may further complicate surgery by obstructing the surgical view during exposure of the anterolateral surface of the medulla and by restricting VA mobilization, which may be necessary in some cases. We present a case of a medullary CM coexisting with an AF, which required tailored surgical strategies for safe and effective resection. To our knowledge, this is the first report to document this combined pathology, accompanied by a surgical video.

Methods: A 25-year-old male presented with right-sided hemiparesis. Magnetic resonance imaging (MRI) revealed a large hemorrhagic medullary CM. The patient underwent a left far-lateral transcondylar approach for resection of the CM.

Results: The AF was encountered intraoperatively and had to be unroofed to achieve an adequate surgical trajectory. Gross total resection was achieved, and the patient made an excellent recovery without postoperative neurological deficit.

Conclusion: The far-lateral approach provides excellent access for resection of anterior medullary CMs. This case highlights the importance of detailed preoperative planning, intraoperative strategy, and real-time navigation, particularly when anatomical variations such as the AF are present. Although the AF may hinder exposure and require tailored adjustments, it does not inherently complicate the entire procedure unless VA mobilization results in vascular injury.