Surgical resection of cerebellum cavernous malformation via suboccipital trans-horizontal fissure approach: Two-dimensional video.

Deep cerebellar cavernous malformations (CMs) pose considerable surgical challenges due to the difficulties in precise localization and achieving minimal invasive exposure during resection [1]. The horizontal fissure (HF), the largest cerebellar fissure, offers a natural cleavage plane to access deep cerebellar structures. This report details a successful deep medial cerebellar CM resection via a suboccipital Trans-HF approach. A 54-year-old male presented with dysarthria and gait instability, with a positive Romberg sign. Preoperative imaging revealed multiple suspected cerebellar CMs, with the largest hemorrhagic lesion situated deeply within the right cerebellum, adjacent to the dentate nucleus, surrounded by prominent developmental venous anomalies (DVAs). After discussion with the patient, microsurgical resection of the largest hemorrhagic CM was elected, informed consent was obtained and the procedure was approved by the ethics committee. Utilizing a prone, Concorde position, and a suboccipital midline craniotomy, the wide right suboccipital HF was identified and allowed for sharp and blunt dissection to enhance exposure [2,3]. Neuronavigation was employed, and the exposed DVAs served as anatomical landmarks to guide surgical trajectory toward the hidden lesion, minimizing parenchymal disruption [4]. Following the CM exposure, the hematoma inside was evacuated for decompression, and the CM was meticulously resected along its gliotic boundary, ensuring the preservation of adjacent DVAs, until complete removal was achieved. Pathological analysis confirmed the diagnosis of CM. Postoperative imaging demonstrated gross-total resection of the target CM with preserved DVAs. The patient exhibited significant symptomatic improvement. This case highlights the nuance of the suboccipital trans-HF approach for resecting deep medial cerebellar lesions.