659 Minimally Invasive Surgery for Spinal CSF-Leaks in Spontaneous Intracranial Hypotension—Technical Aspects and Complications

INTRODUCTION: Spinal cerebrospinal fluid (CSF)-leaks cause spontaneous intracranial hypotension (SIH). In persisting symptoms despite treatment, surgical closure of spinal CSF-leaks is the treatment of choice. METHODS: Since April 2019 SIH patients were operated using the minimal invasive technique of tubular retractors. Leaks were sealed using an interlaminar dorsal access and if necessary a transdural route. Neuromonitoring was used for ventral leaks in the first 16 cases. The primary outcome was the benefit of surgery with respect to orthostatic symptoms; secondary outcome was the occurrence of complications. RESULTS: Between April 2019 and December 2020 we included 58 patients, mean age 46 years (IQR 36-55), 65% female, with the diagnosis of SIH. We treated 38 ventral leaks, 17 dorsal/lateral leaks, 2 CSF-venous fistulas. In all but two patients (96.6%) the leak could be approached, identified and closed via the tubular retractor. Leaks were visualized via a transdural approach, after cutting the dentate ligament and lateralization of the ventral dura. Microspurs were removed and leaks were closed by sandwich patch using a fibrin sealant patch (ventral leaks) or clipping of the respective nerve root (lateral leaks, CSF-venous fistula). At a median follow up of 21.5 months (IQR 16-28), eight patients were lost to follow up and 45 reported a benefit from surgery with respect to orthostatic symptoms. Mild permanent neurologic deficits occurred in 1.7%, the revision rate due to persisting or recurring leak was 3.4% and the overall revisioin rate was 10.3%. CONCLUSIONS: Minimally invasive surgery using tubular retractors of 18-20mm diameter can be safely and effectively performed for closure of spinal dural CSF-leaks in specialized centers.