To evaluate clinical outcomes of patients treated with artificial disc replacement (ADR) and to assess the capacity of this artificial disc replacement for preserving sagittal alignment and motion in the lumbar spine.

24 patients (10 men and 14 women, with a mean age of 46.7 (range 37-65) years) who underwent ADR in one or two segments of lumbar spine and followed up more than 12 months (range, 12-23 months) were reviewed. The level of pain was evaluated using visual analog scale (VAS) for low back and gluteal pain and functional outcome was evaluated using Oswestry Disability Index (ODI). Sagittal alignment and mobility of the lumbar spine were assessed in standing radiographs and dynamic flexion-extension radiographs.

The ODI improved from a mean of 33 (25-47) preoperatively to a mean of 11 (0-24) at the final follow-up. The VAS for lower back pain improved from 74 (50-100) to 23 (0-70) and for gluteal pain, the level improved from 52 (0-100) to 14 (0-60). The mean lordosis of the surgical segments was 16.7° preoperatively, 20.3° postoperatively, and 25.9° at final follow-up (p<0.05). The mean lordosis of the whole lumbar spine was 43.4° preoperatively, 36.9° postoperatively, and 49.4° at final follow-up (p<0.05). Range of motion of the operation segments was 13° preoperatively and 16.2° at the final follow-up, and that of the whole lumbar spine was 46.9° preoperatively and 48.1° at the final follow-up.

These clinical results showed significantly less pain (VAS) and disability (ODI) after the ADR in the short term. In addition, the physiologic sagittal alignment and range of motion could be restored with ADR. The data from more patients and a longer follow-up will be needed to determine if these results can be maintained over the long term.