Safety of low-dose intrathecal fluorescein in endoscopic cranial base surgery

Intraoperative identification of cerebrospinal fluid (CSF) leakage is critical in successful closure after endoscopic cranial base surgery. Intrathecal injection of fluorescein is quite useful in identifying CSF leaks. However, complications have been reported with various doses and the technique has fallen out of favor. We explored the safety of low-dose intrathecal fluorescein administered to patients undergoing endoscopic cranial base surgery.

A retrospective chart review and postoperative patient survey were performed. The nature and incidence of complications and subjective complaints were recorded in 54 patients who underwent endoscopic, endonasal approaches to the anterior cranial base and received intrathecal fluorescein after premedication with dexamethasone and diphenhydramine.

Intraoperative CSF leak was identified with fluorescein in 46.3% of the patients and helped determine the reconstruction technique. Postoperative CSF leak occurred in 9.3% of the patients and resolved with lumbar drainage. There were no seizures. Most side effects were nonspecific, transient, and likely not caused by fluorescein including malaise (57.4%), headache (51.9%), dizziness (31.5%), or nausea/vomiting (24.1%). Three patients (5.6%) experienced persistent subjective lower extremity weakness (n = 2) and numbness (n = 2) postoperatively; however, two of them had undergone lumbar drainage.

Low-dose injection of intrathecal fluorescein after premedication with steroid and antihistamine agents is generally safe. Most symptoms are nonspecific and transient, likely caused by the surgery or lumbar drainage. However, fluorescein should be administered with some caution because it may be responsible for occasional lower extremity weakness and numbness.