152 patients who suffered from discogenic low back pain in one or two motion segments between L3 and S1 were randomized to receive either total disc replacement or instrumented lumbar fusion. The 2-year results of the study indicated that the mean cost per patient was not significant between the two groups; however, total disc replacement was significantly less costly to the health care system. In addition, results indicated that surgical intervention in both groups led to decreases in the number of sick days and significant increases in the quality of life scores.