Factors contributing to failure in endoscopic skull base defect repair

Background: Endoscopic repair of skull base (SB) defects is successful in over 90% of cases. Certain factors may contribute to failure of SB repair techniques or need for secondary repair. Methods: Five-year retrospective review of endoscopic SB defect repairs performed by a single surgeon. Results: Eighty-nine patients undergoing 110 procedures to repair 97 SB defects were evaluated. Etiology of defects included surgical/iatrogenic (64%), spontaneous (17%), traumatic (12%), congenital (6%), and idiopathic (1%). Defects occurred in the sella (41%), sphenoid sinus (18%), ethmoid roof (17%), olfactory cleft (16%), frontal sinus/recess (6%), and middle cranial fossa (2%). Sixty-three patients (71%) underwent primary SB defect repair and 26 patients underwent secondary repair (29%). In revision cases, mean number of prior repair attempts was 1.5 (range, 1-4). Factors potentially contributing to need for secondary SB defect repair included inability to localize SB defect (p = 0.008), development of new SB defect, prior sinus or SB surgery (p < 0.001), prior craniotomy (p < 0.001), prior radiation therapy (p = 0.002), and intracranial infection (p = 0.023). SB defects were successfully closed in 83 patients overall (93%), with success achieved in 97% of primary patients and 85% of secondary patients. Of failures, 3 patients required craniotomy for defect closure, 2 patients underwent permanent cerebrospinal fluid (CSF) diversion, and 1 patient has persistent CSF rhinorrhea. Conclusion: Although endoscopic repair of SB defect remains largely successful, certain factors should alert the surgeon to the potential for failure of repair or need for secondary SB defect repair.