Spinal Extradural Arachnoid Cysts: A Series of 10 Cases.

Background And Objective: Spinal arachnoid cysts are rare lesions, accounting for only 1% of all primary spinal mass lesions. They can occur in extradural, intradural, or intramedullary locations. The extradural cysts are thought to arise from defects in the dura mater through which the arachnoid herniates. This report presents 10 cases of spinal extradural arachnoid cysts and discusses our diagnostic and therapeutic approach to this rare clinical entity.

Patients: The archive records of 10 patients with extradural arachnoid cysts who were treated between 2002 and 2009 were evaluated retrospectively. The study included four male and six female patients. In nine cases, the lesion was symptomatic; in only one case was the cyst diagnosed incidentally. Surgical treatment was performed in the nine symptomatic cases.

Results: In nine of these cases, the extradural cysts were solitary; in one case, multiple extradural cysts were observed. In most of the cases, the lesion was located in the thoracic region. Total excision of the cyst was achieved for all of the cases treated surgically except the case with multiple extradural arachnoid cysts. On follow-up examination, neurologic improvement was observed in all of the surgically treated patients.

Conclusion: Spinal extradural arachnoid cysts are rare pathologies, and treatment options should be considered carefully. In symptomatic cases, total excision of the cyst should be considered the gold standard of treatment. We believe that the closure of the dural defect should be the main surgical goal to prevent recurrence. We propose laminoplasty for the treatment of extradural arachnoid cysts that involve multiple segments to prevent postoperative kyphosis.