Endoscopic repair of lateral sphenoid Encephaloceles: a case series

BACKGROUND: Lateral sphenoid encephaloceles present a surgical challenge. These encephaloceles may be difficult to access given their lateral location and proximity to the neural and vascular structures of the sphenoid floor, pterygopalatine fossa, and lateral and superior sphenoid walls. Additionally, many patients have idiopathic intracranial hypertension, increasing the risk of recurrence. When untreated or undiscovered, these encephaloceles increase the risk of meningitis. METHODS: All consecutive endoscopic repairs of lateral sphenoid encephaloceles by a single surgeon from 2012 to 2017 were analyzed for method of repair, complications, and recurrence rate. Odds ratio for recurrence of CSF leak for Alloderm inlay/abdominal fat sphenoid obliteration/nasoseptal flap with multilayer repair vs. other method (Alloderm onlay/contralateral nasoseptal flap or free mucosal graft) was compared, and Fischer’s exact test was used to calculate the two-sided p-value for the two repair methods. RESULTS: The success rate (no recurrence of cerebrospinal fluid rhinorrhea) for Alloderm inlay/abdominal fat onlay/nasoseptal flap onlay was 100% while for Alloderm onlay/contralateral nasoseptal flap + free mucosal graft the success rate was 0%. For any nasoseptal flap repair vs. free mucosal graft the success rates were 83.3% and 16.7% respectively. The success rate for Alloderm inlay/abdominal fat onlay/nasoseptal flap onlay vs. Alloderm onlay/contralateral nasoseptal flap + free mucosal graft was statistically significant (p = 0.048), but the success rate for any nasoseptal flap repair vs. free mucosal graft was not significant (p = 0.29). The success rate for patients without post-op lumbar drain vs. with post-op lumbar drain was also nonsignificant (p = 0.29). CONCLUSIONS: In the author’s hands Alloderm inlay/abdominal fat onlay/nasoseptal flap onlay was superior to other repair methods (Alloderm onlay/contralateral nasoseptal flap or free middle turbinate mucosa onlay graft). The complication rate was low. Post-operative lumbar drainage did not affect the success rate.