Middle Transclival Endoscopic Endonasal Resection of a Ventral Pontine Cavernous Malformation

The surgical management of lesions within or around the brainstem is usually associated with significant morbidity. Even though several safe entry zones have been described for brainstem lesions, especially cavernous malformations (CMs), their resection remains a challenge due to the convergence of highly functional nerve tracts and nuclei in this rather small structure. Moreover, the ventral location of some of these lesions usually calls for complex surgical approaches involving extensive bone drilling and significant manipulation of neurovascular structures. The expanded endoscopic endonasal approach has been subject to considerable advancements, widening the range of lesions accessible through this route. In this operative video, we describe the surgical nuances of an endoscopic endonasal transclival resection of a ventral pontine CM (Figures 1 and 2). A pedicled nasoseptal flap was harvested for reconstruction, gaining access to the sphenoid rostrum, which was resected. The sellar floor was removed to expose the middle third of the clivus, which was drilled out until posterior fossa dura mater was identified. A centered dural incision was performed to expose the ventral pons and basilar artery. Using image guidance, a limited pial incision over the most superficial aspect of the lesion allowed a prompt drainage of the hematoma and resection of the CM. The surgical cavity was directly inspected through the endoscope, confirming a complete resection. Reconstruction was carried out in a multilayered fashion. The patient presented a postoperative cerebrospinal fluid leak, which resolved with a lumbar drain. Neurologic status remained unchanged after surgery, with the patient displaying a favorable clinical outcome (Video 1).