Recycling the Nasoseptal Flap

Introduction: The use of the vascular-pedicled, nasoseptal flap (NSF) has significantly lowered the rate of cerebrospinal fluid (CSF) leakage after endonasal skull base surgery. Because a wide sphenoidotomy is required for adequate endoscopic skull base exposure, the decision to raise a vascularized flap from the nasal septum must be made early in the procedure. We typically prepare such a flap if the size or location of the target pathology makes a CSF leak more likely. If a CSF leak is not produced, the NSF can be “recycled” and replaced over the septum. We analyzed all of our endonasal skull base procedures for instances when an NSF was prepared and subsequently not required for skull base repair.

Method and Materials: Since the inception of our endonasal skull base program in July 2007 through May 2009, we performed 74 endonasal endoscopic skull base procedures. In 44 of these cases, an NSF was mobilized. The NSF was not required for skull base closure in 13 patients. We analyzed the types of pathology where flaps were not used. The replaced NSFs were assessed in an outpatient setting with endoscopic inspection for adequate healing.

Results: All of the recycled NSFs were found to be healing well onto the septum at last evaluation. No morbidity was associated with the replacement. Eleven of the recycled NSFs were noted in cases of large pituitary macroadenomas. The other two were mobilized for a Rathke's cyst and sellar arachnoid cyst. In several cases, particularly the macroadenomas, descent of a thin, patulous diaphragm after tumor resection made CSF leakage more likely. Conversely, for 11 additional macroadenomas where the NSF was elevated, CSF leakage necessitated its use.

Conclusion: These results support our philosophy for liberal mobilization of an NSF if risk of CSF leakage is elevated. The preemptive technique is most useful for very large pituitary macroadenomas or unspecified cystic lesions. There is no significant morbidity associated with the practice, and in the event of a significant CSF leak, a viable NSF is preserved for skull base closure. We believe more aggressive removal of tumor, even off of the diaphragm, is permitted when adequate provision is made for a CSF leak.