Clinical Results of Lumbar Total Disc Arthroplasty in Accordance With Modic Signs, With a 2-Year-Minimum Follow-up

Study Design. Prospective Study. Objective. The aim of this prospective study is to analyze the influence of Modic type on the clinical results of lumbar total disc arthroplasty. Summary of Background Data. Some patients with lumbar disc degeneration have endplate signal changes on magnetic resonance images, which have been classified by Modic. Modic-1 endplates changes are associated with an inflammatory phase of the disease whereas Modic-2 endplates changes correspond to a quiescent phase with a fatty replacement. The effect of Modic endplate changes on the clinical results of lumbar fusion has been studied by multiple authors, but the influence of Modic type on clinical outcomes of lumbar disc replacement is not known. Methods. A total of 221 patients with a mean age of 42 years were included in this study. Of which, 107 patients were classified Modic 0, 65 Modic 1, and 49 Modic 2. Clinical evaluation (Oswestry Disability Index [ODI], lumbar and radicular pain using the Visual Analog Score [VAS]) was performed preoperatively and at 3, 6, 12, and 24 months minimum postoperatively. Results. Mean follow-up was 30 months (24-72 months). Significant clinical improvement (P < 0.05) was observed in pain and ODI between the preoperative evaluation and final follow-up. Multivariate analysis between the 3 groups demonstrated a significant difference in Oswestry Disability Index (size of the effect was measured at -0.3 [-0.55-0.04]) and on the radicular pain (size of the effect was measured at -0.4 [-0.7-0.1]), with lower scores in the group classified Modic 1. Conclusion. Superior results were achieved in the group of patients with Modic-1 endplate changes on magnetic resonance images. These data may be helpful in patient selection and in preoperative patient counseling.