Management of complex giant spinal arachnoid cysts presenting with myelopathy.

A giant spinal arachnoid cyst is an unusual cause of progressive epidural compressive syndrome. The authors describe 4 cases of a "complex" subtype of this lesion and discuss aspects of surgical management. The patients presented with progressive spastic paraparesis and were found to harbor extensive spinal extradural arachnoid cysts with multiple septations and significant paraspinal extensions. Extensive laminotomy and excision of the cyst along with its extensions were performed in all cases. Compared with previously indexed cases of surgically managed extensive spinal extradural arachnoid cysts, the cases reported here are unique because of their complex nature. Curative treatment consists of radical excision inclusive of the paraspinal extensions as well as closure of a dural defect, if found. A laminotomy or laminoplasty should be performed to avoid postoperative instability related to the extensive exposure. Extended follow-up and instrumentation may be required in select cases.