Endoscopic Endonasal Resection of Temporal Encephalocele and Repair of Cerebrospinal Fluid Fistula at the Lateral Sphenoid Sinus

We demonstrate endoscopic endonasal transsphenoidal resection of a temporal encephalocele (TEn) and repair of a cerebrospinal fistula at the lateral sphenoid sinus. A 48-year-old woman presented with sudden onset of massive serous nasal discharge with severe headache. Head magnetic resonance imaging disclosed medial temporal lobe herniated though a bony defect into the sphenoid sinus. We created a three-dimensional computer model that clearly disclosed TEn protruding between the maxillary and Vidian nerves. We discussed the surgical strategy^1-4 with this three-dimensional model and determined to perform endonasal surgery. With a straight approach to the encephalocele though the maxillary sinus, the trigeminal and Vidian nerves are in the way, requiring retraction of the trigeminal nerve and potentially sacrifice of the Vidian nerve to reach the encephalocele.⁴ Instead, when we approach from the medial side through the sphenoid sinuses with an angled scope, we can reach the encephalocele with mild retraction of the Vidian nerve. We therefore selected the endonasal transsphenoidal approach. Using 30° and 70° endoscopes, the encephalocele was detached from the bony margin, cauterized, and resected (Video 1). The skull base defect was reconstructed with multilayered closure. The postoperative course was uneventful. Magnetic resonance imaging showed that the skull base defect was successfully repaired. TEn is a rare type of meningoencephalocele, which is occasionally associated with Sternberg's canal, a remnant of the craniopharyngeal canal.⁵^,⁶ Using angled endoscopes, malleable forceps, and bipolar coagulators, we could safely access the fistula and excise the encephalocele via the endonasal transsphenoidal approach.