Suboccipital Craniotomy and Transventricular Resection of a Trigonal Medullary Cavernous Malformation: 2-Dimensional Operative Video

Abstract

Brainstem cavernous malformations (CMs) account for 15% to 18% of CMs and are associated with higher hemorrhage rates than other intracranial CMs.1,2 A recent systematic review demonstrated successful long-term outcomes after resection of brainstem CMs in 84% of patients.2 We present a teenage girl with multiple CMs occupying the entire medulla to the C1 cervical spinal cord. This lesion was a trigonal medullary subtype. The patient presented with respiratory distress and new quadriparesis. She had no prior surgical interventions for her lesions. The patient’s guardians provided informed consent for the procedure. A suboccipital craniotomy and transventricular resection were performed. The exophytic component of the lesion was immediately visible on the dorsal cervicomedullary junction. The upper pole was obscured by the cerebellar tonsils. Incising the inferior medullary velum and freeing arachnoid adhesions allowed for mobilization of tonsils and widening of the surgical space. The pia was directly incised at the surface presentation. The hematoma was removed piecemeal to reveal the capsule of the CM. Using sharp round knives can help define the plane between the hematoma and the CM, enabling piecemeal resection. Satellite lesions were then removed. A developmental venous anomaly was encountered, which was obscured on preoperative imaging by the large CM. The developmental venous anomaly should be preserved. It rarely affects the operative approach, although it slightly increases the operative risk.3 Intraoperatively, a large amount of viable medulla remained, despite little being seen on preoperative MRI. The postoperative MRI revealed no residual CM. The patient experienced no new postoperative neurological complications. Video used with permission from Barrow Neurological Institute.