The Endoscopic Endonasal Approach to Repair of Iatrogenic and Noniatrogenic Cerebrospinal Fluid Leaks and Encephaloceles of the Anterior Cranial Fossa

OBJECTIVE: The current approach for the diagnosis and repair of spontaneous and traumatic anterior skull-base defects is oulined, highlighting the controversies that exist in the field and describing the strategies required to access different segments of the anterior cranial fossa. METHODS: We reviewed the literature concerning endoscopic management of anterior skull-base defects. These publications have been combined with our own experience repairing cerebrospinal fluid (CSF) leaks and encephaloceles that developed spontaneously, traumatically, or intentionally as a result of endoscopic skull-base surgery. RESULTS: We present a systematic methodology for the repair of these defects. We have divided our surgical approach into four separate corridors. These are the transnasal, transsphenoidal, transethmoidal, and transmaxillary corridors. Dissection strategies vary for each corridor, but with a combination of approaches, all areas of the anterior skull base can be accessed. Skull-base defects are successfully repaired with a multilayered closure that often involves use of a vascularized pedicled mucosal flap. Adoption of this technique has decreased our rate of postoperative CSF leak from 5.9%-3.1%. CONCLUSIONS: Endoscopic endonasal repair of CSF leaks and encephaloceles has evolved significantly during the past decade. The versatility of different endoscopic approaches through the four endonasal corridors allows for the endoscopic repair of almost all skull-base defects. The use of vascularized pedicled mucosal flaps has evolved to cover these defects as part of multilayered closure strategies.