Endoscopic Management of Spontaneous Clival Cerebrospinal Fluid Leaks: Case Series and Literature Review Fabio Pagella 1 , Alessandro Pusateri 1 , Elina Matti 1 , Cesare Zoia 2 , Marco Benazzo 1 , Paolo Gaetani 2 , Diego Cazzador 3 , Tiziana Volo 3 , Daniele Borsetto 3 , Enzo Emanuelli 3 - OBJECTIVE: Spontaneous cerebrospinal fluid leaks are most commonly located along the anterior skull base. Sphenoidal localization is less common, and clival locali- zation is even rarer. We analyzed a group of patients with spontaneous leaks and selected patients with clival localization. This article discusses surgical management of these entities and provides a brief literature review regarding spontaneous clival leaks. - METHODS: Of a cohort of 67 patients who presented to our departments with a spontaneous leak during the period 2005e2014, a retrospective data analysis was performed on 6 patients with clival localization of the defect. A skull base repair with a multilayered reconstruction was performed in 3 patients, and a single-layered reconstruction using a pedicled nasoseptal flap was performed in 3 patients. - RESULTS: The patients included 6 women with a mean age of 60 years (range, 36e91 years). The mean length of the follow-up period was 69.5 months (range, 22e114 months). The overall success rate of the primary endo- scopic repair was 83.3% (5 of 6 patients); this increased to 100% after revision surgery. - CONCLUSIONS: This series, although numerically limited, suggests that a minimally invasive endoscopic repair of idiopathic clival leaks may be accomplished with an acceptable rate of morbidity and excellent outcomes. More- over, the pedicled nasoseptal flap has been confirmed to be the “workhorse” for the reconstruction of clival defects. INTRODUCTION S pontaneous cerebrospinal fluid (CSF) leaks consist of idiopathic CSF leakages in which no definable cause, such as trauma, previous surgery, or tumor, is present. 1 Spontaneous CSF leaks have been associated with increased intracranial pressure (ICP) and an underlying diagnosis of intracranial hypertension (ICH); moreover, patients with spontaneous CSF leaks are generally middle-aged and obese women—a group of patients who are also at high risk of devel- oping ICH. 2 In patients with spontaneous CSF leaks, clinical and radiographic signs of increased ICP, such as empty sella (80%), arachnoid pits (63%), dural sinus stenosis or thrombosis, dilation of the optic nerve sheaths, and a thinned bone of the skull base, can be found. 3 Patients with spontaneous CSF leaks typically present with a long history of CSF rhinorrhea and episodes of meningitis or brain abscess, which represent the main complications of persistent leaks and could be life-threatening. Spontaneous CSF leaks can occur anywhere along the skull base at the cribriform plate, ethmoid sinus, frontal sinus, sphenoid sinus, and middle ear. However, CSF leaks are generally more common along the anterior skull base, in particular, in the cribri- form plate, where sphenoidal localization is less common. More- over, as reported by Van Zele et al., 4 transclival meningoceles and spontaneous CSF leaks located at the clivus are extremely rare entities, and only a few have previously been described. Persistent CSF leaks should be repaired because of the risk of complications. Endoscopic endonasal surgery for the repair of CSF leaks is currently considered as the gold standard man- agement process. 5,6 A review by Psaltis et al. 7 presented an overall success rate for primary endoscopic repair of spontaneous CSF leaks of 90%, increasing to 96.6% on a second surgical attempt. Moreover, leakages from the sphenoid sinus represent a unique challenge, owing to the Key words - CSF leaks - CSF rhinorrhea - Endoscopic skull base surgery - Skull base repair - Sphenoid sinus Abbreviations and Acronyms CSF: Cerebrospinal fluid ICH: Intracranial hypertension ICP: Intracranial pressure MRI: Magnetic resonance imaging NSF: Nasoseptal flap From the Departments of 1 Otorhinolaryngology and 2 Neurosurgery, Fondazione I.R.C.C.S. Policlinico San Matteo, University of Pavia, Pavia; and 3 Department of Otorhinolaryngology and Otologic Surgery, Azienda OspedalieraePoliclinico of Padova, University of Padova, Padova, Italy To whom correspondence should be addressed: Alessandro Pusateri, M.D. [E-mail: ale.pusateri@gmail.com] Citation: World Neurosurg. (2016) 86:470-477. http://dx.doi.org/10.1016/j.wneu.2015.11.026 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2016 Elsevier Inc. All rights reserved. 470 www.SCIENCEDIRECT.com WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2015.11.026 Technical Note