Surgical outcome of endoscopic endonasal repair of anterior skull base cerebrospinal fluid leaks in a tertiary center

Abstract

Introduction: Cerebrospinal fluid (CSF) leaks are abnormal communications between the subarachnoid space and the nasal cavity and can be classified as spontaneous or traumatic (including iatrogenic fistulas). Various procedures and materials have been described for endoscopic repair. However, the endoscopic technique for repairing CSF leaks is broadly debated. 

Objective: To present the experience of a tertiary center in repairing CSF leaks of anterior skull base.

Methods: A retrospective study was conducted in a tertiary hospital between January 2012 and December 2023. All patients who underwent endoscopic repair of anterior skull base CSF leaks were included. Demographic data, symptoms, diagnostic tests, and intraoperative factors were collected. Descriptive and analytical statistical analysis was performed.

Results: Twenty-nine patients (19 women, mean age 59.6 years) with 30 CSF fistulas were included. The most common etiology was spontaneous, accounting for 59% of all cases, followed by iatrogenic (31%) and traumatic (10%). Seven patients with spontaneous CSF fistulas were obese, with one presenting signs of idiopathic intracranial hypertension. Spontaneous fistulas were most frequently located in the cribriform plate and lateral lamella. The lateral lamella was the most common site for iatrogenic CSF fistulas. The mean defect size was 5,8±7,4mm. Lumbar drainage was placed in 12 patients preoperatively. The underlay-overlay technique was used in 63% of cases, the overlay technique in 33%, and a combined (intracranial and endonasal) approach in 3% (one case). Technique selection was based on etiology, defect size, and surgeon preference. In the underlay-overlay technique, Duragen® underlay and free mucosal grafts overlay sealed with fibrin glue were most used.

For the overlay technique, free mucosal grafts, Surgicel®, and fibrin glue were typically used. The average number of layers per patient was 3.9±1,2. CSF leaks in the cribriform plate were often repaired exclusively with the overlay technique due to the inability to dissect the dura without significantly enlarging the bony defect. No post-operative complications occurred. The surgery was successful in all cases except one case in which reintervention was necessary in the first week after surgery.

Conclusion: A high success rate in correcting CSF leaks of anterior skull base was achieved through an endoscopic approach in our series, which compares to literature in general. Surgical technique must be decided according to etiology, size and location of the defect, with no technique proving to be significantly superior.