Nasoseptal flap necrosis: a rare complication of endoscopic endonasal surgery

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The vascularized nasoseptal flap (NSF) has become the workhorse for skull base reconstruction during endoscopic endonasal surgery (EES) of the ventral skull base. Although infrequently reported, as with any vascularized flap the NSF may undergo ischemic necrosis and become a nidus for infection. The University of Pittsburgh Medical Center’s experience with NSF was reviewed to determine the incidence of necrotic NSF in patients following EES and describe the clinical presentation, imaging characteristics, and risk factors associated with this complication.


The electronic medical records of 1285 consecutive patients who underwent EES at the University of Pittsburgh Medical Center between January 2010 and December 2014 were retrospectively reviewed. From this first group, a list of all patients in whom NSF was used for reconstruction was generated and further refined to determine if the patient returned to the operating room and the cause of this reexploration. Patients were included in the final analysis if they underwent endoscopic reexploration for suspected CSF leak or meningitis. Those patients who returned to the operating room for staged surgery or hematoma were excluded. Two neurosurgeons and a neuroradiologist, who were blinded to each other’s results, assessed the MRI characteristics of the included patients.


In total, 601 patients underwent NSF reconstruction during the study period, and 49 patients met the criteria for inclusion in the final analysis. On endoscopic exploration, 8 patients had a necrotic, nonviable NSF, while 41 patients had a viable NSF with a CSF leak. The group of patients with a necrotic, nonviable NSF was then compared with the group with viable NSF. All 8 patients with a necrotic NSF had clinical and laboratory evidence indicative of meningitis compared with 9 of 41 patients with a viable NSF (p < 0.001). Four patients with necrotic flaps developed epidural empyema compared with 2 of 41 patients in the viable NSF group (p = 0.02). The lack of NSF enhancement on MR (p < 0.001), prior surgery (p = 0.043), and the use of a fat graft (p = 0.004) were associated with necrotic NSF.


The signs of meningitis after EES in the absence of a clear CSF leak with the lack of NSF enhancement on MRI should raise the suspicion of necrotic NSF. These patients should undergo prompt exploration and debridement of nonviable tissue with revision of skull base reconstruction.

ABBREVIATIONS BMI = body mass index; EEA = endoscopic endonasal approach; EES = endoscopic endonasal surgery; LOS = length of stay; NSF = nasoseptal flap; RTOR = return to operating room; WBC = white blood cell.

Article Information

Correspondence Juan C. Fernandez-Miranda, Department of Neurological Surgery, University of Pittsburgh Medical Center, 200 Lothrop St., Pittsburgh, PA 15213. email:

INCLUDE WHEN CITING Published online July 21, 2017; DOI: 10.3171/2017.2.JNS161582.

Disclosures Dr. Snyderman is a consultant for SPIWay.

© AANS, except where prohibited by US copyright law.



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    Intraoperative findings. Left: Intraoperative endoscopic view of a necrotic NSF (circle) after all postoperative debris was removed. Right: Intraoperative endoscopic view of a viable NSF in a patient with a postoperative CSF leak. The arrow denotes the area of dehiscence that led to the development of a CSF fistula. Note the difference in coloration between the flaps and the presence of purulent material over the necrotic flap.

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    Search string. A retrospective chart review of all patients who returned to the operating room (OR) during the 4-year study period.

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    MRI findings. Postoperative coronal T1-weighted MRI sequences with and without contrast in patients with necrotic (A and B) and viable (C and D) NSFs. The arrows indicate an inverted-U shape conforming to the defect. The necrotic NSF does not enhance with contrast, while the viable NSF shows robust, uniform enhancement.



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