CLOSURE OF CSF LEAKS OF THE ANTERIOR SKUL L BASE USING INTRATHECAL SODIUM FLUORESCEIN

Background: For more than 25 years, intrathecal 5% sodium fluorescein has been routinely used at the University ENT Hospital at Graz during surgical closures of CSF leaks of the anterior skull base. Especially with endoscopic approaches, this technique has been of significant hel p in identifying and localizing dural defects. No fluorescein-related complications occurred in the series reported. Material and Methods: I n a retrospective study, indications, techniques, and results of surgi cal closures of CSF leaks of the anterior skull base are reviewed. Dur ing 5 1/2 years from 1990-1995, 72 patients with CSF-rhinorrhea were o perated on at our department, 69 of whom had sodium fluorescein applie d intrathecally. In 41 patients strictly endoscopic techniques were ap plied, in 22 patients an external approach was chosen and in 9 cases c ombined approaches were used. Defects in the roof of the ethmoid, the lamina cribrosa, and in the sphenoid sinus almost exclusively were app roached endoscopically. Defects in the posterior table of the frontal sinus, especially when located laterally, were approached from externa lly or via combined endonasal and external routes. The causes of the C SF leaks, their localization, and the surgical approaches chosen are a nalysed and the surgical techniques described in detail. Results: The direct coronal CT of the paranasal sinuses/anterior skull base proved to be significantly better in detecting lesions compared to axial CT i mages (82% vs. 53%). In all cases intrathecal fluorescein allowed for a precise localization of the defect(s). There were no fluorescein rel ated complications in this series. In one patient with massive frontob asal chip fractures and substantial dural defect, a rhinosurgical clos ure was not successful. Two patients developed recurrent fistulae afte r several months and years respectively. One of these patients had to be operated 3 times until permanent closure was achieved. Two patients had to be revised because of mucoceles of the frontal sinuses, in bot h cases the initial closure of the dural defect proved to be tight. Co nclusion: Our results demonstrate that with exception of defects of th e posterior lateral table of the frontal sinus, CSF leaks of the rhino basis can be closed safely endoscopically. After a follow-up from 19-6 5 months, the overall success rate for 72 CSF leaks was at 94.5%. When applied correctly, the fluorescein technique proves to be an extremel y helpful technique for diagnosis and surgery of CSF leaks.