Closure of skull base defects after endoscopic endonasal transsphenoidal surgery: the role of the local sphenoid mucosal flap for low flow leaks.

Abstract

A local sphenoid mucosal flap (SMF) is naturally raised during endonasal exposure of the sella. Typically, these flaps are repositioned; however, they could be used in place of a nasoseptal flap (NSF) for closure of low-grade CSF leaks. In this study, we aim to establish the safety and efficacy of SMF closure for low-grade CSF leaks and to assess the impact on sinonasal quality of life (QoL) compared to NSF closure. In a consecutive, prospective cohort of anterior skull base pathology, data regarding sellar and suprasellar extension (Hardy grade), cavernous sinus invasion (Knosp grade), intraoperative (Kelly grade) and postoperative CSF leak, and sino-nasalQoL data (SNOT-22) were analysed. Of 187 patients with no/low flow (Kelly 0-1) intraoperative CSF leak, 127 (67.9%) received a SMF and 60 (32.1%) received a NSF. A total of 141/187 (75.4%) had nointraoperative leak, while 46/187 (24.6%) had grade-1 leaks. SMF were used in 70.9% (100/141) of cases without intraoperative leak, and 58.7% (27/46) of cases with Kelly grade-1 leaks. Hardy grade 4, grade E and Knosp grade 4 lesions were all more commonly closed with a NSF (p < 0.05). Two patients (1.1%) had postoperative CSF leaks, both in the SMF group, and both after no discernibleintraoperative leak. Sinonasal QoL was below baseline for up to 3months postoperatively. SMF cases tended to have better sinonasal QoL for up to 6weeks after surgery. Thus, in the largest cohort to date, SMF are a safe alternative to NSF for closure low-grade skull base defects. Sinonasal QoL was better in the first 6weeks after SMF closure than NSF closure.