Cerebrospinal fluid leakage due to nasoseptal flap partial necrosis: A pitfall for skull base reconstruction of endoscopic endonasal surgery

Background: Vascularized nasoseptal flaps allow for the reconstruction of large dural defects and have remarkably reduced the incidence of postoperative complications during endoscopic endonasal skull base surgery. Nevertheless, some complications related to nasoseptal flap have been reported. Flap necrosis is a rare, but serious issue is associated with meningitis and cerebrospinal fluid (CSF) leak. Case Description: We performed endoscopic endonasal removal of the tuberculum sella meningioma in a 39-year-old woman with a history of Turner syndrome using abdominal fat, fascia, and a vascularized nasoseptal flap for dural and skull base defect reconstruction. After surgery, she developed CSF leak, and reoperation revealed partial necrosis of the septal flap that caused leakage. At this time, with a concern that removal of the necrotic part may lead to the insufficient size of the flap, we filled the gap tightly with fat pieces. However, the CSF leak recurred, and thus, we performed debridement of the necrotic region and reformed the multilayered reconstruction, following which she no longer experienced CSF leakage. Conclusion: Our case suggested that partial rather than total flap necrosis could occur, possibly due to variances of vascular anatomy, leading to focal ischemia. Debridement of the necrotic region may be an important solution for recurrent cerebrospinal leakage secondary to partial necrosis of a nasoseptal flap.