Endonasal transsphenoidal transclival removal of prepontine epidermoid tumors: technical note

Prepontine retroclival tumors have typically been removed through a variety of anterolateral, lateral, and posterolateral cranial base approaches. Here, we describe an endonasal transclival cranial base approach for removal of prepontine epidermoid tumors.

Two men, 40 and 52 years old, each presented with a history of headaches and cranial nerve deficits. In each patient, magnetic resonance imaging showed a large T1 hypointense/T2 hyperintense mass occupying the posterior suprasellar, premesencephalic, and prepontine cisterns, with significant mass effect on the brainstem. Both patients underwent an endonasal transsphenoidal transclival cranial base tumor removal with the operating microscope and endoscopic assistance. The dural and bony defects were repaired with abdominal fat grafts, collagen sponge, titanium mesh, and cerebrospinal fluid diversion. One patient developed a postoperative cerebrospinal fluid leak and meningitis requiring two reoperations to repair, ultimately with fat and fascia lata grafts.

At 1 year after surgery, both patients have improved compared with their preoperative neurological state, and volume analysis of preoperative and 1-year postoperative magnetic resonance imaging scans confirm a marked reduction in mass effect on the brainstem, with a 78% tumor removal in one patient and 76% removal in the other. Both patients have normal endocrine function.

The endonasal approach offers a minimally invasive, anatomically direct route for removing prepontine epidermoid tumors that obviates brain retraction. The use of angled endoscopes is essential for gaining lateral, cephalad, and caudal visualization to augment the limited microscope view. Inadequate repair of clival dural defects remains the greatest potential pitfall in attempting transsphenoidal transclival tumor removal.