Predictive value of MRI vertebral end-plate signal changes (Modic) on outcome of surgically treated degenerative disc - Disease results of a cohort study including 60 patients

Objective. - To assess the predictive value of MRI vertebral end-plate changes (Modic) on clinical outcome of surgically treated lumbar single-level degenerative disc disease (DDD). Methods. - A cohort of 60 patients was included. Patient groups were similar in respect of age, gender and clinical presentation, allowing comparisons. Patient age ranged from 30 to 72 years (mean: 45.8 years). All patients suffered severe chronic low back pain for more than 6 months, with single-level symptomatic DDD. All patients experienced segmental instrumented interbody (n=22) or posterolateral (n=38) fusion. Clinical outcome was assessed by using a visual analog scale (VAS) and the functional disability scale of the Japanese Orthopaedic Association (JOA) for lumbar spine. The number of patients for each Modic group was as follows: Modic type 0, n=15; Modic type I, n=22; Modic type II, n=14; and Modic type IIII, n=9. Fusion rates were similar for each Modic group of patients. Mean follow-up was 14 months. Results. - The pre-operative mean VAS improved by 53.5% (from 8.2 +/- 2. 0 to 3.8 +/- 1.9, p<0.05) and the pre-operative mean JOA score by 58% (from 5.5 +/- 2.1 to 11.0 +/- 2.4, p < 0.05). Patients harboring Modic type 1 changes improved much better than others (p<0.05). Conversely, clinical outcome of patients presenting with Modic type II lesions was poor. Conclusion. - This study confirms instrumented fusion as an effective treatment in symptomatic lumbar DDD. Preoperative combination of low back pain of discal origin and severe DDD with Modic type I lesion on MRI may lead to excellent results after fusion in a large proportion of patients. Conversely, arthrodesis for patients harboring Modic type II abnormalities implicates smaller benefit of doubtful clinical significance.