===== General information ===== Nontraumatic [[leak]]s primarily occur in adults > 30 yrs. Often insidious. May be mistaken for allergic [[rhinitis]]. Unlike traumatic leaks, these tend to be intermittent, the sense of [[smell]] is usually preserved, and [[pneumocephalus]] is uncommon ((Calcaterra TC, English GM. Cerebrospinal Rhinorrhea. In: Otolaryngology. Philadelphia: Lippincott-Raven; 1992:1–7)). ---- Spontaneous [[Cerebrospinal fluid fistula]]s are most commonly located along the [[anterior skull base]]. Sphenoidal localization is less common and, among these, clival localization is even rarer. They represent a surgical challenge because of their high recurrence rates. The most important factor for obtaining a successful repair in these patients is reducing their intracranial pressure through nutritional, medical or surgical means ((Martínez-Capoccioni G, Serramito-García R, Huertas-Pardo B, García-Allut A, Martín-Martín C. Spontaneous Cerebrospinal fluid fistulas in the anterior skull base: a surgical challenge. J Laryngol Otol. 2015 Apr;129(4):358-64. doi: 10.1017/S0022215115000584. PubMed PMID: 25907278. )). ===== Etiology ===== Sometimes associated with the following ((Nutkiewicz A, DeFeo DR, Kohout RI, et al. Cerebrospinal Fluid Rhinorrhea as a Presentation of pituitary neuroendocrine tumor. Neurosurgery. 1980; 6:195– 197)): 1. agenesis of the floor of the [[anterior fossa]] ([[cribriform plate]]) or [[middle fossa]] 2. [[empty sella syndrome]]: primary or post-transsphenoidal surgery 3. increased [[ICP]] and/or [[hydrocephalus]] 4. infection of the [[paranasal sinus]]es 5. tumor: including [[pituitary neuroendocrine tumor]]s, meningiomas 6. a persistent remnant of the [[craniopharyngeal canal]] ((Jonhston WH. Cerebrospinal Rhinorrhea: The Study of One Case and Reports of Twenty Others Collected from the Literature Published Since Nineteen Hundred. Ann Otolaryngol. 1926; 35)) 7. [[AVM]] ((Calcaterra TC, English GM. Cerebrospinal Rhinorrhea. In: Otolaryngology. Philadelphia: Lippincott-Raven; 1992:1–7)). 8. congenital anomalies: most involve [[dehiscence]] of bone a) dehiscence of the foot plate of the stapes (a congenital abnormality) which can produce CSF rhinorrhea via the [[eustachian tube]] ((Calcaterra TC, English GM. Cerebrospinal Rhinorrhea. In: Otolaryngology. Philadelphia: Lippincott-Raven; 1992:1–7)). b) dehiscence below [[foramen rotundum]]. ===== Spontaneous posterior fossa cerebrospinal fluid fistula ===== [[Spontaneous posterior fossa cerebrospinal fluid fistula]] ===== Case series ===== 67 patients with a spontaneous leak between 2005 and 2014, retrospective data analysis was performed on six patients with clival localization of the defect. Three patients received a skull base repair with a multilayered reconstruction, and three patients underwent a single-layered reconstruction using a pedicled nasoseptal flap. The patient cohort included six women with a mean age of 60 (36-91 years old). The mean length of the follow-up was 69.5 months (22-114 months). The overall success rate of the primary endoscopic repair was 83.3% (five out of six), this increased to 100% after revision surgery. This series, though 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. Moreover, nowadays the pedicled nasoseptal flap has been confirmed to be the "workhorse" for the reconstruction of clival defects ((Pagella F, Pusateri A, Matti E, Zoia C, Benazzo M, Gaetani P, Cazzador D, Volo T, Borsetto D, Emanuelli E. Endoscopic management of spontaneous clival CSF leaks: case series and literature review. World Neurosurg. 2015 Nov 25. pii: S1878-8750(15)01546-6. doi: 10.1016/j.wneu.2015.11.026. [Epub ahead of print] PubMed PMID: 26626813. )). ---- Eight patients were managed via an endoscopic approach and one patient through an intracranial approach. The MRI/T2-FLAIR test was used for localization of the site of the leak. The test confirmed the site of Cerebrospinal fluid fistula in 6 patients. Successful repair of CSF rhinorrhea was achieved in 7 of 8 patients with a single endoscopic procedure; one patient required two procedures after a re-leak 18 months following the first repair. Non-traumatic CSF rhinorrhea is a relatively rare condition and occurs secondary to different etiologies. Among multiple techniques available for localization, MRI/FLAIR is effective but requires further evaluation and polishing. In the absence of a large skull base lesion or tumor, endoscopic repair of CSF fistula carries a high success rate with a high margin of safety and low morbidity rate ((Al-Sebeih K, Karagiozov K, Elbeltagi A, Al-Qattan F. Non-traumatic cerebrospinal fluid rhinorrhea: diagnosis and management. Ann Saudi Med. 2004 Nov-Dec;24(6):453-8. PubMed PMID: 15646164; PubMed Central PMCID: PMC6147856. )). ====Case reports==== Cruz et al., report the case of a 28-year-old woman with a spontaneous Cerebrospinal fluid fistula from the sleeve of a redundant thoracic nerve root. She presented with postural headaches and orthostatic symptoms indicative of intracranial hypotension. CT myelography revealed that the lesion was located at the T-11 nerve root. After failure of conservative management, including blood patches and thrombin glue injections, the patient was successfully treated with surgical decompression and ligation of the duplicate nerve, resulting in full resolution of her orthostatic symptoms ((Lopez AJ, Campbell RK, Arnaout O, Curran YM, Shaibani A, Dahdaleh NS. Spontaneous Cerebrospinal fluid fistula from an anomalous thoracic nerve root: case report. J Neurosurg Spine. 2016 Dec;25(6):685-688. PubMed PMID: 27367938. )).