Roentgenographic evaluation of ossification and calcification of the lumbar spinal canal after intradiscal betamethasone injection.

There have been reports of lumbar spinal canal ossification and calcification after triamcinolone intradiscal injection therapy. Our objective was to observe the roentgenographic changes after betamethasone intradiscal injection therapy for lumbar disc diseases. The subjects were 183 patients (498 discs; 130 men and 53 women) who underwent discography and betamethasone intradiscal injection therapy and were followed for a mean of 5 years and 7 months. Ossification and calcification appeared de novo (three patients, three discs) or enlarged (four patients, five discs) in the outer layer of the posterior annulus fibrosus or posterior longitudinal ligament in eight discs among seven patients (3.8%). The incidence and degree of ossification and calcification in our patients were significantly lower than those reported in previous studies, and a long time elapsed before ossification and calcification appeared or enlarged. Intradiscal injection of betamethasone did not appear to confer any incremental relative risk for lumbar spinal canal ossification and calcification based on review of follow-up roentgenographs.