Spontaneous CSF Leak Due to Clinically Occult Elevated ICP

Object: The purposes of this study are to (1) establish mildly increased intracranial pressure (ICP) as the primary pathophysiologic cause of spontaneous cerebrospinal fluid (CSF) leaks; and (2) demonstrate that in cases involving multiple leaks, a surgical approach affording direct visualization of the dural defects is required for cure. Methods: All patients presenting to the University of Wisconsin Neurosurgery or Otolaryngology Department with a chief complaint of spontaneous CSF leak since 2005 were included. Demographics and clinical characteristics were collected after a retrospective review of their medical record. A literature review was then performed via PubMed using search terms including spontaneous CSF leak , spontaneous rhinorrhea , spontaneous otorrhea , temporal encephalocele , and frontal encephalocele . Results: Thirteen patients were studied with a mean age of 54.9 years. In these patients, CSF leaks were located in the middle fossa (9/13) or anterior fossa (4/13), occurring in the skull base foramina or naturally thin bone. Five had preoperative hearing loss; none had significant worsening postoperatively. Seven patients had undergone a previous surgery for obliteration of a CSF leak. Importantly, 9/13 patients had more dural defects leading to CSF leak than were identified on preoperative imaging. The CSF opening pressure was measured preoperatively in 10 patients with a mean of 22.7 cm H 2 0. All 13 patients underwent craniotomy for direct visualization of the area of the CSF leak with layered closure. Only one has recurred with follow-up ranging from 0 to 32 months. Conclusions: Development of spontaneous CSF leakage is related to chronically elevated ICP. Our findings indicate a low-level increase over a long period of time is sufficient. This is supported by the fact that our patients present in their 5th decade of life or later, consistent with previous reports. In cases of highly elevated CSF opening pressures, a ventriculoperitoneal shunt or CSF diversionary procedure should be considered as these patients are at high risk for recurrence of their CSF leak, regardless of operative approach. Lastly, patients presenting with spontaneous CSF leaks due to chronically increased ICP are at significant risk of having multiple dural defects. Imaging rarely identifies all the defects, making a procedure affording direct visualization necessary to fully address the leak. Otherwise, recurrence is highly likely.