Dural repair after intraoperative CSF leakage in endoscopic endonasal skull base surgery without pedicled nasoseptal flap: is it a safe surgical technique?

In this study we evaluated the outcome and efficacy of a multilayer closure technique of the sellar floor after transsphenoidal endoscopic approaches for sellar pathologies in correlation to the intraoperative grading of cerebrospinal fluid (CSF) leak. Overall 280 patients were reviewed retrospectively who underwent endonasal transsphenoidal endoscopic surgery for sellar pathologies from January 2011 to April 2020. Among them, 87 patients had an intraoperative cerebrospinal fluid leak and were included in this study. The intraoperative cerebrospinal fluid grading was based on the classification by Esposito. Clinical outcomes were evaluated based on postoperative complications and development of postoperative cerebrospinal fluid leak in correlation to the used closure technique and material of dural and skull base reconstruction. Their association with the intraoperative cerebrospinal fluid leak grade, underlying pathology and the tumor size were analyzed as well. From the 87 patients, there was 54 women (62%) and 33 men (38%). The mean age was 56.3 ± 14.8. The most frequent histological diagnosis was non-secreting adenoma in 40 cases (45%), followed by the secreting adenomas with 16 cases (18%). Eight cases of meningioma (9%), six cases of Rathke's cleft cyst (7%), six cases of craniopharyngioma (7%), four cases of colloid cysts (4%), four chordomas (4%) were observed. Of the 87 patients with intraoperative cerebrospinal fluid leaks, 20 cases were classified as grade 1, 37 cases as grade 2 and 30 cases as grade 3. The materials used for the closure of grade 1 were primarily sealant sponge Tachosil ® (70%), followed by fibrin glue (55%) and bone (55%). For grade 2, Tachosil ® (78%), bone (57%) and autologous fat graft (54%). In grade 3 dural leaks, the combination of lumbar drains (90%), autologous fat graft (87%) and fascia lata (60%) were mainly used. Only nine patients developed a new postoperative cerebrospinal fluid leak in this series, and were treated conservatively with lumbar drains, but only three of them discontinued by this method. The remaining six patients with persistent postoperative cerebrospinal fluid leak underwent revision surgery. The analyzed multilayer closure technique correlated to the intraoperative CSF leakage for endoscopic transsphenoidal surgery has been shown to be safe. This study shows a lower intraoperative cerebrospinal fluid leak rate compared to other studies and similar rate of postoperative cerebrospinal fluid leak (3.1% vs. 3.9%) compared to the pedicled vascular flap and other techniques in the literature. Based on these results, the multilayer closure represents a real alternative to nasoseptal flap application in selected cases. However, in large defects and complex reconstruction of anterior skull base defects, use of lumbar drain and pedicled nasoseptal flap should remain the gold standard of treatment.