Abstract
BACKGROUND: Spinal arachnoid cysts are rare and have varied clinical manifestations depending on the affected spinal region and nerve roots. A complete cyst excision with fistula closure is the first choice of treatment. However, it might be difficult to localize the specific position of the fistula because previous images have no enhancements or the fistula is too tiny to be detected. CASE PRESENTATION: This case is a giant lumbar extradural arachnoid cyst. We administered a lumbar injection with contrast medium into subarachnoid space under digital subtraction angiography (DSA) and disclosed the fistula. Confirming the location of fistula enabled us to perform minimally invasive surgery to ligate the fistula. Surgical intervention for a spinal arachnoid cyst might encounter the problem of the formation of a postoperative cerebrospinal fluid (CSF) fistula. We propose the option of detecting the fistula preoperatively for minimal invasive surgery. Recurrence depends on the long-term follow-up, and more cases are needed to further evaluate our technique. CONCLUSIONS: The real-time contrast medium technique for spinal arachnoid cysts contributes to the complete ligation with minimally invasive surgery.