A total of 250 patients who underwent EES between June 2020 and March 2021 were retrospectively reviewed in this consecutive series. During this period, we performed EES for skull base tumors such as pituitary adenoma, craniopharyngioma, tuberculum sellae meningioma, and Rathke’s cleft cyst. The degree of intraoperative CSF leak was assessed using the grading scale suggested by Esposito et al . Ninety-seven patients showed an intraoperative grade II or III CSF leak and were included in the study. Patients without an intraoperative CSF leak, patients with a grade I CSF leak, and those with tumors involving the posterior fossa were excluded from this study. The study was approved by the institutional review board of our institution and was performed in compliance with relevant ethical guidelines.
Medical records of the included patients were reviewed to collect data, including demographic variables (sex, age, and BMI), diagnosis, intraoperative CSF leak grade, sellar reconstruction method used, and length of stay (LOS) in the hospital postoperatively. To investigate the integrity of NSF, postoperative MRI and rhinological status were also examined by a dedicated neuroradiologist and otorhinolaryngologist, respectively.
Details of the EES have been described previously [8, 23]. The entire surgery was performed by an endoscopic skull base surgery team comprising a neurosurgeon (D.S.K.) and an otorhinolaryngologist (S.D.H.) at a single institution. During the EES, rigid endoscopes (diameter, 4 mm; length, 18 cm; with 0º, 30º, or 45º angle of view lenses; KARL STORZ Endoscopy Korea Co., Ltd., Seoul, Korea) were used in combination with a robotic holding arm (POINT SETTER, Mitaka Kohki Co., Ltd., Tokyo, Japan). All endoscopic procedures were recorded using a high-resolution camera and video recording system (KARL STORZ Endoscopy Korea Co., Ltd., Seoul, Korea).
For grade II CSF leak, we placed a fibrin sealant patch (TachoSil®, Takeda Pharmaceutical Co., Ltd., Osaka, Japan), followed by an NSF. In contrast, for cases involving grade III CSF leaks, the sellar reconstructive method included the following multi-layer technique. In this technique, (i) a collagen matrix (DuraGen®, Integra LifeSciences, New Jersey, USA) was first placed into the arachnoid defect. Thereafter, (ii) an acellular dermal graft (AlloDerm®, BioHorizons®, Alabama, USA or MegaDerm®, L&C BIO, Gyeonggi-do, Korea), tailored according to the size of the sellar bone defect, was overlaid as an on-lay dura graft. (iii) HXA (Hydroset®, Stryker Leibinger, Freiburg, Germany) was then injected for additional closure of the sellar defect; at this step, no intraoperative CSF leak was observed from the reconstructed graft site 5–10 min after HXA injection. Finally, (iv) the NSF, already harvested at the beginning of EES, was used to cover the layered materials; thus, HXA was not exposed to the nasal cavity. Compression was applied with (v) a 12-Fr balloon catheter or two pieces of Merocel® (Medtronic, Minneapolis, USA) to stabilize the graft. Postoperatively, LD was not routinely performed.
Three antibiotics (third-generation cephalosporin, quinolone, and metronidazole) were intravenously administered for 3–5 days. Intravenous or oral steroid (hydrocortisone) replacement was performed pre- and postoperatively. To identify the degree of tumor resection and the integrity of NSF, sellar MRI was performed one day after surgery, and otorhinolaryngological examination was performed on days 2 and 5 postoperatively. All patients were followed up at an otorhinolaryngology and endocrinology outpatient clinic at 1 week after discharge and at a neurosurgery outpatient clinic 3 weeks after discharge.
Independent variables associated with CSF leaks were analyzed using univariate analysis. The postoperative LOS was compared between the CSF leak grade II and grade III groups using an independent sample t-test. P < 0.05 was considered statistically significant. Statistical evaluations were accomplished by SPSS® Statistics 27 (IBM Co., New York, USA)