Abstract:

BACKGROUND: Now, most studies related to adjacent segment degeneration only analyze the changes of motion segments above and below the fusion. There were no controlled studies on adjacent segments to all the other unfused segments after instrumented posterior fusion.
OBJECTIVE: To study measurement of adjacent lumbar segments and evaluate long-term radiographic changes in all adjacent lumbar segments after instrumented posterolateral lumbar fusion.
METHODS: Totally 42 digitized radiographs of lateral lumbar spine from 6 corpse skeletons were obtain through different projections and specimen postures (every specimen with 7 projection). Fifty-seven patients with posterolateral lumbar fusion were followed-up from 1.5 to 4 years. Digitized radiographs of them were photographed before fusion surgery and final follow-up. Distortion-compensated roentgen analysis (DCRA) method was used to measure sagittal angle, disc height, and dorsoventral displacement in all the above data.
RESULTS AND CONCLUSION: There were no statistical significance in sagittal angle, disc height, and dorsoventral displacement under different postures by using DCRA method (P > 0.05). No changes were observed at the segments located below the fusion. All the unfused segments above the fusion showed significant changes of sagittal angle and disc height. It is indicated that the radiographic changes of posterolateral lumbar fusion suggest the disc degeneration of the segments above the fusion.