Is it possible to have total disc replacement following lumbar discectomy?

It was thought that instability following discectomy would preclude the use of total disc replacement in lieu of fusion. A recent study for the Federal Drug Administration compared results of total disc replacement, TDR, in 20 patients who had previous lumbar discectomy, and 67 patients who had not had previous lumbar surgery for disc herniation. The results showed that there was no significant difference between the two groups based on all four of the outcomes that were measured at follow up.