Modic Changes and Disc Degeneration of Nonfused Segments 27 to 45 Years After Harrington Instrumentation for Adolescent Idiopathic Scoliosis

Study Design. A case-control study. Objective. The aim of this study was to investigate the long-term prevalence of the Modic changes and disc degeneration in the nonfused segments of the surgically treated adolescent idiopathic scoliosis (AIS) patients and compare with age-and sex-matched healthy controls. Summary of Background Data. No studies have looked at the association between Modic changes and low back pain in patients who underwent AIS surgery many years ago. Methods. Study subjects consisted of 194 patients with AIS who underwent spinal fusion with Harrington instrumentation between 1968 and 1987. Twenty-six patients (AIS group) underwent lumbar magnetic resonance imaging (MRI), whole spine X-ray, and patient-reported outcomes evaluations [Scoliosis Research Society-22 Patient Questionnaire (SRS-22), Oswestry Disability Index (ODI)]. The mean duration of follow-up observation was 36.1 years. The lowest fusion vertebra was used as follows: T12: 2 patients, L1: 4, L2: 11, L3: 6, L4: 2, L5: 1. Twenty-nine healthy age-and sex-matched individuals were selected as a control (CTR) group. Results. On the basis of MRI findings, a significantly higher percentage of subjects showed Modic changes in the AIS group (AIS group: 57.7%, CTR group: 13.8%). There were no significant differences in the percentage of subjects with disc degeneration rated Pfirrmann grade 4 or higher (AIS group: 61.5%, CTR group: 65.5%). SRS-22 scores for function and self-image were significantly lower in the AIS group. ODI was significantly worse in the AIS group. Modic changes in AIS group were found in the concave side of the curve in 61.9%. The magnitude of lumbar coronal curve was found to be a significant risk factor of Modic changes. Conclusion. Modic changes were observed in 57.7% of AIS patients 27 years or more after spinal fusion with Harrington instrumentation. The magnitude of lumbar coronal curve was found to be a significant risk factor of Modic changes. Modic change occurred at a higher frequency in AIS patients than CTR individuals, with lower function and worse ODI scores.