Localization of symptomatic lumbar pseudarthroses by use of discography.

Twenty-four patients with lumbar pseudarthroses following attempted fusion were investigated by preoperative discography. The pseudarthroses were confirmed at surgical exploration. In 19 patients, discography at the level of a pseudarthrosis reproduced typical back pain, and in two patients the level above the fusion reproduced typical pain. Discography is not indicated when the major symptoms are leg or buttock pain. Technical errors included injection into the annulus fibrosis and impingement of the needle into the vertebral endplate. The latter may produce a false-positive result. Previous posterior fusions and very narrow disc spaces prevented insertion of the needle in some patients. Not all lumbar pseudarthroses were symptomatic, and two frequently occurred in the same patient. Discography is a useful adjunct to the traditional investigation of lumbar pseudarthroses.