Spinal Extradural Arachnoid Cyst

A spinal extradural arachnoid cyst (SEAC) results from a rare small defect of the dura matter that leads to cerebrospinal fluid accumulation and communication defects between the cyst and the subarachnoid space. There is consensus for the treatment of the dural defect, but not for the treatment of the cyst. Some advocate a total resection of the cysts and repair of the communication site to prevent the recurrence of a SEAC, while others recommended more conservative therapy. Here we report the outcomes of selective laminectomy and closure of the dural defect for a 72-year-old and a 33-year-old woman. Magnetic resonance imaging of these patients showed an extradural cyst from T12 to L4 and an arachnoid cyst at the posterior epidural space of T12 to L2. For both patients, we surgically fenestrated the cyst and repaired the dural defect using a partial hemi-laminectomy. The patient's symptoms dramatically subsided, and follow-up radiological images show a complete disappearance of the cyst in both patients. Our results suggest that fenestration of the cyst can be a safe and effective approach in treating SEACs compared to a classical complete resection of the cyst wall with multilevel laminectomy.