SB Charié Artificial Lumbar Disc Replacement: Early Results From Short-Term Follow-Up

BACKGROUND: Spinal fusion has been regarded as "gold standard" in spine surgery for the treatment of degenerative disc disease or instabilities in patients unresponsive to conservative treatment. Nevertheless, increased stresses on mobile segments adjacent to fusions accelerate adjacent level degeneration, which may present as combinations of disc degeneration, instability, and spinal stenosis. Inspired by the excellent results of total hip and knee replacements, SB charite prosthesis whose advantage over spinal fusion is the preservation of segmental motion has been invented. The purpose of total disc replacement (TDR) is to restore the basic motion of the intervertebral segment and to protect the adjacent levels against unphysiologic loading.OBJECTIVE: To introduce the new surgical technology of SB charite artificial lumbar disc replacement . To evaluate early clinical outcomes of patients treated with disc replacement and assess the capacity of this intervertebral disc replacement for preserving motion in the lumbar spine.METHODS: Sixteen patients who received artificial disc replacement between 2002 and 2006 were analyzed retrospectively. There were 10 males and 6 females with an average age of 42.8 years. Five cases were at L4/L5 and 11 cases were at L5/S1, which all received artificial lumbar disc replacement via retrospective approach and were included into replacement group. Thirty patients who had posterior lumbar interbody fusion between 2003 and 2006 were included into control group (fusion group). The group was composed of 20 males and 10 females. The mean age was 41.6 years. Ten cases were at L4/L5 and 20 cases were at L5/S1.The age, sex, disease course, pre-operative score of VAS (visual analogue scale) and ODI (Oswestry disability index) of the two groups were evaluated and there were no significant difference between the two groups. All cases were assessed with VAS and ODI postoperatively. The capacity for preserving motion was also evaluated in the replacement group.RESULTS: All cases were followed for more than 12 months with an average of 20 months. All patients of the two groups had a significant reduction in pain and disability postoperatively. The relative improvement on low back pain VAS of fusion patients was more significant than of replacement patients at earlier evaluation. Fusion patients had a significant reduction on radicular pain VAS at earlier evaluation but by 6 months the relative improvement was similar for the two groups. There was no statistical difference on ODI of both groups by 6 months postoperatively. Greater motion was found at L4/L5 for disc replacement patients than fusion patients. A similar trend was noted at L5/S1.CONCLUSIONS: The clinical outcomes of Disc replacement was satisfied over short-term follow-up. Compared with fusion, disc replacement does act to preserve motion at surgical level, but the more important benefit of protection of adjacent levels can only be assessed by long-term follow-up.