Postsurgical ossified extradural cyst of the lumbar spine : a case report

An extremely rare case of postsurgical ossified extradural cyst is reported. The imaging and intraoperative findings are described and compared with those in cases previously reported in the literature. To draw attention to this rare but dangerous condition that can develop after lumbar surgery. Only six cases of postsurgical ossified extradural cyst have hitherto been reported. A 65-year-old man who had undergone surgery for a herniated lumbar intervertebral disc 20 years earlier complained of leg pain. From the imaging and intraoperative findings an ossified cyst with closed communicating aperture was diagnosed. The ossified cyst was surgically resected. Postoperatively, this patient was discharged and experienced alleviation of his symptoms. This case showed an extremely rare postsurgical ossified extradural cyst, and was of particular interest because in contrast to the previously reported cases the communicating aperture between the cyst and subarachnoid space was closed.