Endoscopic endonasal repair of CSF leak

Cerebrospinal (CSF) rhinorrhea commonly occurs as result of trauma and iatrogenic disruption of the skull base and secondary to inflammatory, neoplastic, and pseudotumor syndromes. Endoscopic reconstruction of skull base defects aims to reestablish tissue planes and completely separate the cranial from the sinonasal cavity, employing a multilayered reconstruction. Small bony defects can be closed with a single layer of inlay autologous fat or fascia, followed by tissue sealant. Sellar lesions involving a bony defect without intraoperative CSF leak can be closed by packing the cavity with Gelfoam and reconstructing the bony sella with vomer or artificial graft. In the presence of intraoperative CSF leak, the tumor cavity is packed with autologous abdominal fat followed by reconstruction of the bony sella and tissue sealant. Larger skull base defects with a high-volume intraoperative CSF leak require multilayered closure. This can be achieved with an autologous fat graft in the tumor cavity followed by fascia lata, bony buttress, and tissue sealant. These larger skull base defects can be supplemented with a gasket seal closure. This consists of fascia lata centered over the defect with the edges of the graft exceeding the bony defect circumferentially, covered by a piece of rigid material such as vomer or similar artificial material, countersunk into the bony defect. The use of a pedicled nasal septal vascular flap based on the nasoseptal artery is increasingly employed. The flap is harvested at the beginning of the operation, before posterior septectomy. During reconstruction, the nasal septal flap is incorporated as a final layer of closure in addition to the previously placed gasket seal or bony buttress and inlay graft and secured in position with fibrin glue ensuring that it is not twisted along its pedicle and the mucosal surface is facing the nasal cavity.