Primary dural closure and anterior cranial base reconstruction using pericranial and nasoseptal multi-layered flaps in endoscopic-assisted skull base surgery

Introduction: Dural and anterior cranial base reconstruction is essential in the surgical resection of a craniofacial tumor that extends from the paranasal sinuses to the subdural space. Watertight reconstruction of vascularized tissue is essential to prevent postoperative liquorrhea, especially under conditions that prevent wound healing (e.g., postoperative irradiation therapy).

Method: We successfully treated two cases of olfactory neuroblastoma by endoscopic-assisted craniotomy with primary dural closure and anterior cranial base reconstruction using a multi-layered flap technique. Dural defects were closed using temporal fascia or fascia lata in a conventional fashion, immediately after detaching the subdural tumor, in order to isolate and prevent contamination of subdural components and cerebrospinal fluid (CSF) from the tumor and nasal sinuses. Tumor removal and anterior cranial base reconstruction were performed without any concern of CSF contamination after dural closure by craniotomy and endoscopic endonasal approach (EEA). Vascularized pericranial flaps (PCF) and nasoseptal flaps (NSF) were used simultaneously as doubled-over layers for reconstruction.

Results: The tumor was completely removed macroscopically and the anterior cranial base was reconstructed in both cases. CSF leak and postoperative meningitis were absent. Postoperative and irradiation therapy courses were successful and uneventful.

Conclusions: This multi-layered anterior cranial base reconstruction consisted of three layers: a fascia for dural plasty and double-layered PCF and NSF. This surgical reconstruction technique is suitable to treat craniofacial tumors extending into the subdural space through the anterior cranial base dura mater.