Pontine cavernous malformations are difficult to reach and pose a higher risk of symptomatic rehemorrhage compared with their supratentorial counterparts. Resection of CMs along the floor of the 4th ventricle has been associated with worse functional outcomes. Complete resection of the CM and evacuation of the hematoma can provide the patient with relief of some of the presenting symptoms and a chance for long-term cure.
In this video, the author attempts to describe technical nuances for resection of large posterior pontine CMs. He presents the case of a 32-year-old man who presented with 2 brainstem hemorrhages within a 2-month interval related to his newly diagnosed pontine CM near the floor of the 4th ventricle. The lesion was resected through a midline suboccipital craniotomy and telovelar route. The floor of the 4th ventricle was mapped using a monopolar probe and the facial nucleus was noted to be displaced more medially. A small incision within the lateral floor of the ventricle allowed exposure of the CM and drainage of the hematoma. Bipolar coagulation was kept to a minimum to protect the brainstem fiber tracts, and the CM was debulked and removed piecemeal. Arterial feeders were coagulated and cut while the associated developmental venous abnormality was protected. The CM was removed in a gross total fashion as confirmed by postoperative MRI. The patient suffered from transient worsening of his facial weakness immediately after surgery. However, his neurologic deficits had significantly improved by the 1-month follow-up examination.