Transforaminal Endoscopic Extradural Onlay Patch Graft Repair of Spontaneous Spinal Type 1a Cerebrospinal Fluid Leaks: A Case Series

BACKGROUND AND OBJECTIVES: Spontaneous spinal cerebrospinal fluid (sCSF) leaks represent a significant source of morbidity, presenting with symptoms of spontaneous intracranial hypotension. Type 1a leaks are classified as ventral dural tears, with thoracic defects proving to be especially challenging to diagnose and treat. Epidural blood patches remain first-line for many cases; however, their efficacy is variable. Traditional surgical management of sCSF leaks typically involves open laminectomy with transdural direct suture repair, with attendant risks due to wide laminectomy and spinal cord exposure/manipulation. This study demonstrates that endoscopic extradural repair technique is a reliable minimally invasive alternative for treating type 1a sCSF leaks. METHODS: A transforaminal endoscopic extradural approach with subsequent onlay patch repair technique was performed on 11 patients with spontaneous type 1a CSF leaks at spinal levels ranging from T2-3 to L1-2. All patients were from a single institution from 2024 to 2025. Data on clinical outcomes, perioperative variables, and risk factors for reoperation were collected. RESULTS: Eleven patients (8 female:3 male) underwent endoscopic repair with DuraGen, TachoSil, and TISSEEL with adjunctive lumbar drain placement for CSF diversion. 81.8% of patients experienced resolution of their symptoms and returned to normal daily activities within 3 months. The mean estimated blood loss was 11.1 mL, operative time averaged 170 minutes, and average length of stay was 6.8 days due to preplanned CSF diversion. Two patients underwent reoperation for recurrent/persistent leak, without satisfactory resolution of symptoms after reoperation. One incidence of a small nonoperative pneumothorax occurred. CONCLUSION: In this study, a single-surgeon cohort of 11 patients underwent transforaminal endoscopic extradural repair of type 1a sCSF leaks. The results suggest that transforaminal endoscopic extradural approach with onlay patch repair is a safe and effective alternative to existing surgical techniques for type 1a CSF leaks. Additional studies are warranted for further characterization, direct comparison with traditional techniques, and long-term outcome assessment.