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Skull base cerebrospinal fluid fistula.

A skull base CSF fistula occurs when there is a defect at the skull base and the subarachnoid space communicates with the extracranial space. Galen in the 2nd century aD was the first to describe leakage of CSF after cranial trauma.5 The term “rhinorrhea” was coined by Thomson3 while describing spontaneous nasal CSF leaks in patients. There exist a number of constants in neurosurgery with respect to achieving good outcomes for our patients. These include an intimate knowledge of surgical anatomy, meticulous technique to avoid injury to vital tissue, sharp attention to hemostasis, and so forth. This issue of Neurosurgical Focus deals with one of these constants that is paramount in cranial, skull base, and spinal neurosurgery, that is, exclusion of the CSF space from the external environment. Failure to obtain adequate closure, resulting in the loss of CSF and the communication of privileged internal space with the exterior milieu, can have a disastrous influence on the eventual outcome of an otherwise uneventful operation. Techniques to restore or maintain seclusion of the space occupied by CSF around the brain and spinal cord is the subject of this issue. The importance of closing the dural defect was put forward by Grant in 1923.2 Walter Dandy,1 in 1926, published the first report on the surgical repair of CSF rhinorrhea. He used muscle and fascia to close a frontal sinus defect. Using an endoscope in the repair of a skull base defect was proposed by Wigand in 1981.4 In recent years endonasal endoscopic approaches to the cranial base have been particularly in vogue. Therefore, it should come as no surprise that this issue has a particular emphasis on techniques applied in these procedures to achieve satisfactory closure. This aspect of contemporary cranial base surgery has taken advantage of the unique expertise of neurosurgeons and our otorhinolaryngology colleagues. Our ability to traverse the nasoand oropharyngeal spaces to reach the skull base and intracranial compartment has realized significant advancements in the past years. New biological and structural materials as well as innovative vascularized tissue transfer techniques have contributed equally to an enhanced ability to create seals that prevent egress of CSF. The level of facility with these techniques, built on the collective experience of others in our field, is demonstrated in this issue. Treating CSF fistulas, whether from surgical or accidental trauma, remains a critical clinical and surgical challenge. Our results are certainly not perfect; however, a high standard is reachable with adherence to certain principles and proficiency with contemporary techniques. (http://thejns.org/doi/abs/10.3171/2012.5.FOCUS12164)