Title:
Low-dose intrathecal fluorescein and etiology-based graft choice in endoscopic endonasal closure of CSF leaks.

Abstract:
Skull base cerebrospinal fluid (CSF) leaks of various etiologies are increasingly repaired through the natural corridor using an endoscopic endonasal approach. Characteristics of the skull base defect significantly correlate with etiology, which should be ascertained to guide surgical management. The objectives of this study were to assess the long-term outcomes of patients that underwent endoscopic endonasal repair of CSF leak using low-dose intrathecal fluorescein (ITF) and an etiology-based algorithm for multi-layer graft closure.
Patients were divided into 4 groups: A--congenital, B--post-traumatic, C--post-endonasal surgery, D--post-craniotomy. Low-dose ITF was utilized in all case series. Long-term clinical follow-up data, including perioperative complications associated with the use of intrathecal fluorescein and leak closure rates, were obtained retrospectively. Endoscopic visualization of fluorescein-stained CSF as well as the method of skull base closure and graft material is detailed.
We identified a total of 41 patients (N=24 in Group A, N=4 in Group B, N=12 in Group C and N=1 in Group D) that underwent 50 CSF leak repairs using the endoscopic endonasal approach with an average follow-up of 31.6 months. Nine patients (21.9%) had undergone a previous attempt at CSF leak repair. Lumbar drain was used intraoperatively in 26 patients (63.4%) and kept in place for an average duration of 3.25 days. ITF successfully identified the site of leak in 80.5% of cases regardless of etiology. Leaks were successfully closed in 92% of patients. One patient (2.4%) experienced transient leg weakness following lumbar drain placement. Another patient (2.4%) developed hydrocephalus requiring a ventriculoperitoneal shunt.
Low-dose ITF is a safe and useful adjunct to endoscopic endonasal repair of CSF leaks with minimal complications and successful localization of the leak in approximately 80%. An etiology-based approach to graft choice and duration of lumbar drain placement in CSF leak repair may optimize closure rates.