Anterior Cranial Fossa Defects: Technical Account of Repair with an Open, Non-Buttressed Approach

Introduction: Defects of the anterior skull base can arise spontaneously, secondary to trauma or after surgical manipulation. Although the focus has recently leaned toward endoscopic endonasal repairs, there are cases where open repair is still warranted. Frontal sinus fractures often require cranialization of the sinus, and extensive sinonasal malignancies and other anterior skull base tumors also often result in a large basal defect after resection. There have been reports of repairs requiring a buttress to hold repair materials in place and/or avoid brain sag. This buttress is usually either a split-thickness bone graft or synthetic titanium mesh. The objective of this study was to evaluate the authors’ technique of repairing anterior fossa defects and to assess the durability without the use of a buttress.

Methods: We performed a retrospective review of patients treated for an anterior skull base defect between July 2007 and September 2012. We included patients undergoing concomitant tumor resection and patients with traumatic injury requiring cranialization of the frontal sinus. There were 27 patients (B = 11, W = 16) included in the review, 8 female and 19 male, which totaled 28 surgical repairs. Etiology of the defect included 3 spontaneous, 13 tumors (2 in which the defect was noted in a delayed fashion after surgical resection of the lesion), and 12 traumatic cases. Failure was defined as CSF leak after repair.

Results: All but one case were repaired via a bifrontal approach (one lateral sphenoid sinus defect was repaired through a lateral frontotemporal approach). Materials used for repair included pericranium (alone or in a combination), collagen-based dural matrix, and dural sealant. Bone cement was used in six cases, two of which did not have available pericranium, and two in which the defect occurred after transsphenoidal resection of a lesion. Split-thickness bone graft or titanium mesh was not used in any of the cases. Mean follow-up was 19.1 weeks (range, 1-128 weeks). There was a 100% success rate, with no evidence of wound infections or neurovascular damage in the follow-up period.

Conclusion: Anterior cranial fossa defects can be safely and effectively repaired without the use of a buttress. The combination of vascularized pericranium, a collagen-based dural graft matrix, and dural sealant provides a good seal, and bone cement may be supplemented when pericranium is not available.