Rapid Intrathecal Fluorescein Injection During Cerebrospinal Fluid Leak Repair Is Safe and Effective.

Objective: Intrathecal fluorescein (IF) is effective for localizing nasal cerebrospinal fluid (CSF) leaks along the skull base during endoscopic exploration, with largest studies reporting sensitivities ranging from 66%-93%. Due to reports of intraoperative and postoperative neurologic complications such as seizures and paralysis, surgeons often dilute the fluorescein and inject it intrathecally slowly over a variable amount of time. However, no study has assessed whether rapid IF administration causes the aforementioned risks or whether it affects its accuracy in identifying CSF leaks intraoperatively.

Methods: A prospective study was conducted from 2015 to 2024, where all patients undergoing endoscopic exploration and/or repair of CSF rhinorrhea had 0.1 mL of 10% fluorescein (10 mg) mixed with 3-5 mL of patients' CSF injected rapidly via the lumbar drain over a few seconds.

Results: Of the 82 included patients, the mean age was 53.8 ± 15.2 years, and 84% were female. Sixty-nine patients underwent successful endoscopic CSF leak repairs, and 13 had negative endoscopic explorations. Rapid IF injection was 80% sensitive (20% false negative rate) and 100% specific for identifying CSF leaks, and it caused no seizures, paralysis, or other neurologic complications.

Conclusion: Compared to prior reports of slow low-dose IF injection for CSF leak localization, rapid IF injection yielded similar efficacy (80% sensitivity) with no IF-related complications. Rapid IF injection was safe and effective but should be corroborated by future studies.

Level of evidence: 4: