Spontaneous cerebrospinal fluid leaks and encephaloceles: multi-institutional collaborative retrospective analysis of 468 cases with special focus on recurrent cases

Purpose: Spontaneous cerebrospinal fluid (s-CSF) leaks and encephaloceles pose significant challenges in diagnosis, treatment, and long-term management. Although their association with idiopathic intracranial hypertension (IIH), obesity, and obstructive sleep apnoea is increasingly recognized, predictors of recurrence remain unclear. This study analyses a large multi-institutional cohort of patients with s-CSF leaks, with a specific focus on recurrent cases. Methods: A multicenter retrospective cohort study was performed. Patients with confirmed s-CSF leaks who underwent surgical repair were included. Demographic, clinical, radiological, and surgical data were collected. Results: A total of 468 patients were included, predominantly women (70.7%) with elevated BMI (> 25 in 82.1%). The olfactory cleft was the most common leak site (39.9%), followed by the sphenoid sinus (27.8%) and the ethmoidal roof (23.3%). Radiological signs suggestive of IIH were present in 64.7% of patients. Endoscopic endonasal repair was performed in 95.5% of cases, with intrathecal fluorescein used in 55.1% and lumbar drain in 3.6%. Postoperative complications occurred in 8.1%, and recurrence was documented in 7.9% of cases. In only 37.8% of recurrent cases, the leak recurred at the same anatomical site. No clinical, surgical, or radiological variable was significantly associated with recurrence. Conclusion: s-CSF leaks are predominant in obese women with radiological features of IIH. Despite this strong association, no independent predictors of recurrence were identified, highlighting the complexity of the underlying mechanisms. Long-term prospective studies are required to better define prognostic factors and optimize management strategies.