Endoscopic, Transnasal, Transclival Resection of a Pontine Cavernoma

Introduction: Recent advances in endoscopic technique have made it feasible for surgeons to access vascular lesions of the skull base through the endoscopic, endonasal corridor. Although this approach represents a significant departure from traditional open surgery, the central tenets of vascular surgery remain unchanged. We present our experience with endoscopic endonasal resection of a pontine cavernoma, and we review the growing literature on this topic.

Clinical Presentation: A 17-year-old male patient presented with acute onset of headache and facial numbness. Magnetic resonance imaging demonstrated an enhancing lesion presenting to the ventromedial pons consistent with a cavernous malformation. The patient subsequently experienced acutely worsening neurological deficits progressing to complete left hemiparesis and gaze palsy. A purely midline ventral endoscopic, transnasal, transclival approach was used to resect the cavernoma. Postoperatively, he had transient worsening of his left-sided motor function and restricted horizontal gaze. He developed a cerebrospinal fluid leak requiring temporary CSF diversion and a revision of the skull base closure. At last follow-up his hemiparesis had improved, and his MRI demonstrated a radiographic cure.

Review of the Literature: Although craniotomy remains the gold standard approach for vascular lesions, a subset of these lesions may lend themselves to endoscopic midline ventral approaches. Endonasal endoscopic approaches have been described in five published case reports—paraclinoid, superior hypophyseal, anterior communicating, vertebral artery, and PICA aneurysms—as well as one report of an intraosseous arteriovenous malformation of the skull base. The chief limitation of this approach remains the need to obtain adequate exposure and hemostasis and to limit postoperative CSF leaks.

Conclusions: The endoscopic, transnasal, transclival approach is a novel approach to select vascular lesions of the skull base. A pontine cavernous malformation presenting to the ventral surface can be a safe and effective option for patients, providing the most direct surgical corridor to pontine cavernomas. Recently developed techniques for closure and repair of the skull based defect have minimized, but not eliminated, the risk of CSF leak in these procedures.