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 I/II, 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 I 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.