Endoscopic endonasal obliteration of the frontal recess and anterior skull base.

BACKGROUND Although endoscopic techniques have become more widespread in repair of frontal sinus (FS) defects, certain pathologies still require open approach (extensive trauma or tumors). Under certain circumstances even multiple complex open reconstructive procedures might fail to resolve persistent pneumocephalus or CSF leak and subsequently surgeons tend to escalate the invasiveness and employ even more complex and aggressive approaches. We present our experience treating persistent pneumocephalus or CSF leak after previously failed transcranial reconstruction utilizing an endoscopic endonasal approach (EEA). METHODS We retrospectively reviewed a prospectively maintained database of all patients undergoing an EEA for repair of persistent pneumocephalus or CSF leak following FS cranialization between 2016 and 2020. RESULTS Six patients who underwent cranialization of the FS with subsequent persistent pneumocephalus or CSF leak were identified; two patients suffered a traumatic fracture of the FS, remaining four patients had undergone previous cranial surgery. Clear violation of the FS was not recognized in one patient. All patients underwent cranialization of the FS either directly following initial craniotomy or during open repair of a FS fracture. Two patients underwent multiple transcranial surgeries including using vascularized free tissue transfer. Complete cessation of pneumocephalus/CSF leak was achieved in 83.3% (5/6) after the first and 100% (6/6) after two endoscopic procedures. No morbidity or mortality resulted from the endoscopic procedure. CONCLUSIONS Skull base defects following a failed cranialization of FS are usually located in or in close proximity to the frontal recess. These defects can be safely and effectively repaired via an EEA.