Radiologic Analysis of Kinematic Characteristics of Modic Changes Based on Lumbar Disc Degeneration Grade.

OBJECTIVE: The kinematic characteristics of Modic changes (MCs) in the lumbar spine have rarely been reported; furthermore, the effect of disc degeneration (DD) on segmental motion has not been considered in analyzing the motion characteristics of MCs. Therefore, this study was designed to evaluate the kinematic characteristics of MCs based on different DD grades.

METHODS: 894 patients with 4470 lumbar segments were reviewed, and those with MCs were selected for segmental motion evaluation. MC type was defined as 0, I, II, and III, and DD grade was classified into 5 groups from grade A to grade E. Segmental angular and translational motion were calculated from X-ray images in positions of flexion and extension, and the absolute values of the differences were recorded.

RESULTS: MCs were observed in 308 segments from 260 patients. No MC was found in DD grade A, and MC III was not observed in DD grade B. MC I was found to significantly increase angular motion in the DD grade E group, and MC II could enlarge translational motion in the DD grade D group (all P < 0.05); MC III had the lowest segmental motion in both angular and translational motion; There was no statistical difference in angular and translational motion between MC I and II in all DD grade groups (all P > 0.05).

CONCLUSIONS: MC III indicates the final stable phase of segmental motion. MC I might increase angular motion, and MC II would increase certain translational motions in the segments that were believed to be stable.