Spontaneous Transclival Cerebrospinal Fluid Fistulae

Abstract

Introduction: A transclival spontaneous fistula is a rare event. It usually becomes symptomatic and is detected by means of either CSF rhinorrhea or intracranial complications such as meningitis. Different skull base variants of normality have been described in anatomic and radiological literature. Of special interest to surgeons is the possibility that some of such bone variants occur in the embryological formation of the anterior skull base, resulting in a local bone defect or persistence of a vascular canal in the clivus that might become symptomatic after a precipitating factor such as skull base approaches. Case Report: We present a case of a CSF fistula due to a clival bone defect manifesting after transsphenoidal surgery for a pituitary microadenoma. We did not consider it a postsurgical complication because no extended approach was employed and the clival bone was not drilled by surgical maneuvers. The case is illustrated with pre-, intra-, and postoperative images, and the pathophysiology of spontaneous transclival fistula, as well as its possible complications and management, is discussed with basis in current literature. Conclusion: The authors suggest that the patient harbored an embryological remnant, previously described as “canalis basilaris medianus,” which, after resection of clival mucosal layer, communicated the CSF space around the clival area with the retropharynx. The possibility of detecting such embryological remnants preoperatively and its consequences of alerting to the possibility of early postoperative fistulas make this report of value for skull base surgeons.