BACKGROUND: Closure of spontaneous sphenoid sinus cerebrospinal fluid leaks can be challenging because of the relative inaccessibility of the lateral recess and the presence of intracranial hypertension. We present our experience of such cases and highlight factors associated with a successful outcome.METHODS: Eleven patients with spontaneous, laboratory confirmed, sphenoid sinus cerebrospinal fluid leaks were included. All patients underwent endoscopic closure by either a three-layer technique or fat obliteration.RESULTS: In all but one patient, the leak was successfully sealed (success rate, 90.9 per cent; mean follow up, 37.1 months). Elevated intracranial pressure was measured in eight patients, two of whom did not exhibit relevant clinical or radiological characteristics. Five patients received diuretics and dietary advice for weight reduction. In one patient with recurrence two weeks after repair, successful revision was performed by additional placement of a ventriculoperitoneal shunt (follow up, 67 months).CONCLUSION: Long-lasting cerebrospinal fluid fistula sealing in the sphenoid sinus requires stable reconstruction of the defect in three layers or fat obliteration if the anatomy is unfavourable. All patients should be intra- and post-operatively screened for elevated intracranial pressure to identify those who need additional intracranial pressure reduction measures.