The mid-term follow-up results of artificial disc replacement for discogenic low back pain

Abstract

Objective To evaluate the mid-term clinical and radiographic results of artificial disc replacement (ADR) for discogenic low back pain.Methods From July 2004 to July 2007,21 patients with discogenic low back pain,aged from 26 to 67 years,underwent lumbar ADR with the Charite Ⅲ artificial disc at 22 levels and Activ L prosthesis at 2 levels:L4-5 5 cases,L5S1 13 cases,L4-5 and L5S1 3 cases.The diagnosis was proved by discography in all the patients.The clinical and radiographic results were evaluated and compared between pre-,post-operation and finial follow-up.Results All patients were followed up for 4to 7 years (average,5.1 years).There were statistical differences between pre-operation and final follow-up in Oswestry disability index and Visual Analogue Scale for back pain and leg pain.All the prostheses were mobile without dislocation,breakage,subsidence or spontaneous fusion,only a slight scoliosis was noted in one patient.At the ADR levels,the anterior and posterior intervertebral height increased averagely 6.3 mm and 1.9 mm respectively,the lordosis increased 2.9°,and the mean range of motion (ROM) was 4.6°.At the adjacent level proximal to ADR,the intervertebral height and lordosis decreased slightly,and the ROM decreased 2.5°.The total lumbar lordosis increased 7.8°,and the total lumbar ROM increased 2.4°.According to MRI and CT scans,the degeneration of proximal adjacent disc and facet were not evident,however the degeneration of facets at the ADR levels was evident.Conclusion The 5 years results of ADR for discogenic low back pain were satisfactory,with preserved motion at the ADR level,and the degeneration of adjacent level was not evident.However,there was obvious degeneration in facet joints of the ADR level. Key words: Intervertebral disk; Low back pain; Prostheses and implants; Treatment outcome