The Utility of Computed Tomography and Intrathecal Fluorescein in the Management of Cerebrospinal Fluid Leak

Abstract

Background Intrathecal fluorescein (IF) has become a common tool for localization of cerebrospinal fluid (CSF) leak, but despite frequent use, IF lacks Food and Drug Administration approval. The diagnostic ability of high-resolution computed tomography (HRCT) has increased over several decades. Subspecialized rhinology training within otolaryngology has, similarly, allowed for dedicated skull base surgeons to become more adept at CSF leak localization. Objectives To evaluate the utility of HRCT and IF in CSF leak localization. To identify certain patient populations in which IF has added utility. To analyze the ability of fellowship-trained neuroradiologist and rhinologist to localize CSF leak sites. Methods Data were collected from a single, tertiary care academic institution. Patients admitted for CSF leak between 2003 and 2016 were included. Diagnostic yield of preoperative imaging and IF for identification of leak site was analyzed. Fellowship-trained neuroradiologist and rhinologist performed retrospective review of CT imaging and identified CSF leak sites. Results One hundred and two patients underwent CSF leak repair. Skull base defects were preoperatively localized to exact sinus on imaging report in 67% of patients. Preoperative imaging stratified by CT slice thickness of 0.625 mm identified leak site in 88.9% of cases. Blinded retrospective review by a neuroradiologist and rhinologist was able to localize the CSF leak to the correct or adjacent sinus in >80% of cases. IF was useful for intraoperative localization in 73% of cases. When preoperative imaging failed at leak site localization, IF was able to correctly identify leak site in 75% of cases. Conclusions The diagnostic yield of IF and CT imaging was equivalent, with each modality localizing leak site approximately two-thirds of the time. CT imaging with 0.625 mm slice thickness proved more efficacious in identification of skull base defects. IF demonstrated increased utility in instances where preoperative imaging has failed at leak site identification.

The Effectiveness and Safety of Intrathecal Fluorescein in the Management of Cerebrospinal Fluid Leaks

“…22 A study in 2020 also demonstrated IF to have a superior diagnostic yield for identifying CSF leaks compared to CT in the presence of multiple leak sites. 23 Our results demonstrate that the use of IF in our centre is safe and effective at identifying CSF fistulae. We found that there was a 90.0% rate of positive localisation for CSF fistulae sites with IF use.…”

“…22 A study in 2020 also demonstrated IF to have a superior diagnostic yield for identifying CSF leaks compared to CT in the presence of multiple leak sites. 23…”

“…The most recent study showed a 9% complication rate however all complications were attributed to other causes (such as bacterial meningitis and spinal headache related to LP). 23 Therefore, although several side effects of IF are known, these have been generally described as transient and mild in the existing literature.…”

Intraoperative Injection of Normal Saline Through Lumbar Drainage for Transnasal Endoscopic Repair of Complex CSF Leaks

“…To further identify the leaks intraoperatively, the previously commonly used methods are intrathecal fluorescein injection, breath holding, and compression of the jugular vein to increase intracranial pressure. There is no doubt about the role of intrathecal fluorescein injection in further locating the leaks during surgery, but it is off-label use ( 13 ), and the consequences are unacceptble once complications occur; intraoperative compression of the jugular vein and breath holding can be used to assist in locating the leaks, but the effect is not significant. So, the above methods limit the further identification of complex leaks.…”

Detection of Cerebrospinal Fluid Leaks Using the Endoscopic Fluorescein Test in the Postoperative Period following Pituitary and Ventral Skull Base Surgery

“…2,4,5 At present, postoperative CSF leaks are diagnosed at most institutions using a variable combination of patient reporting, radiographic imaging modalities, Beta 2 transferrin testing, and bedside endoscopic evaluation with and without the use of ITF injection. 6 ITF administration carries with it the risk of chemical meningitis, but the low doses of ITF used for the diagnosis of CSF leaks have been well established as having an excellent safety profile. 5,7 Commonly reported adverse effects experienced by patients following ITF administration are transient, nonspecific, and frequently attributable to the lumbar puncture / drain rather than fluorescein itself.…”