Systematic Review: Evaluating the Efficacy of Intrathecal Fluorescein for Localizing Cerebrospinal Fluid Rhinorrhea

A defect in the skull base can result in leakage of cerebrospinal fluid (CSF) out of the subarachnoid space into the sinonasal cavities, termed CSF rhinorrhea. Patients presenting with CSF rhinorrhea often require surgical repair, typically performed endoscopically. Successful surgical intervention is highly reliant on accurate identification of the leak site. Identification can be enhanced by the administration of intrathecal fluorescein (IF) via a lumbar drain before surgery. The objective of this systematic review is to better characterize the benefits and limitations of IF administration.A systematic search was conducted for literature documenting the use of IF for CSF leak localization. The results of this search were subjected to initial review, followed by full-text evaluation of selected texts, and final inclusion based on predetermined selection criteria. Primary outcomes were specificity and sensitivity of IF administration in identifying CSF leak sites. Secondary outcomes included administration technique and safety data.A total of 25 studies representing 3801 instances of IF administration met inclusion criteria. When injected slowly for up to 30 minutes at doses of50 mg, IF administration results in minimal complications. A total of 25 mg doses (92.36%) of IF appear more sensitive than 10 mg (71.88%) doses of IF while maintaining a similar safety profile. Mixing fluorescein with double distilled water instead of CSF or saline may decrease waiting times before fluorescein can be identified and increase its safety profile.Intrathecal fluorescein may play an important role in the identification of CSF leak site during endoscopic repair.