Computed tomography of the postoperative intervertebral disc and lumbar spinal canal: serial long-term investigation in 19 patients after successful operation for lumbar disc herniation.

The first part of this work, published in 1988, included 25 patients who had computed tomographic (CT) scans without contrast enhancement and plain x-rays of the lumbar spine before, 1 week after, and 6 to 7 weeks after a successful operation for lumbar disc herniation. The present study extends the follow-up period to 3 years in 19 of the 25 original patients. Clinical examinations, lateral plain x-rays, and CT scans without contrast enhancement of the operated disc were repeated. The results indicate a decrease or even a disappearance of the hyperdense extradural material thought to represent fibrosis. An image suggestive of persistent disc herniation was still present in 5 of 8 patients with this finding on early postoperative CT scans. Persistent intradiscal gas was seen in nearly half of the patients. Total normalization of the posterior extraspinal structures was the rule. There was no correlation between CT appearance and residual complaints of the patients. CT scans without contrast enhancement may be sufficient to guide the surgeon in postoperative patients with massive signs and symptoms of recurrent root compression in whom a second operation is indicated on clinical grounds. In all other cases, myelography followed by CT scans is considered appropriate to investigate failed back surgery syndrome.