Risk Factors for Cerebrospinal Leak after Endoscopic Skull Base Reconstruction with Nasoseptal Flap

Objective/Hypothesis: The use of expanded endonasal surgery (EES) in the treatment of skull base neoplasms has increased significantly in recent years. Since 2006, the nasoseptal flap (NSF) has become the workhorse for the closure of skull base defects involving the anterior skull base, planum, sella and clivus. We hypothesized that defect site impacts the rate of CSF leak following EES.

Study Design: Retrospective cohort study.

Methods: Patients who underwent skull base defect repair using a NSF at the UCSF minimally invasive skull base center were retrospectively reviewed. Patient demographics, disease, and defect location and size were recorded along with the presence of a postoperative CSF leak. Data was analyzed using Fisher's exact test.

Results: 121 patient met inclusion criteria. Ten patients had a nasoseptal flap failure with CSF leakage, two in the anterior skull base (ethmoid, cribiform, planum), and eight in the central skull base (clivus, sella) (p = 0.047). Dural defect size > 2.0cm2 in the central skull base strongly correlated with the risk of flap failure (p = 0.031).

Conclusions: This study of endoscopic closure of skull base defects using a NSF demonstrates there is an association between both surgical site and dural defect size with NSF failure. Expanded defects of the sella and clivus have an increased risk of failure and may warrant augmented techniques.