The Changes of Adjacent Segments after Long Segment Posterolateral Fusion: Comparative Study of 3 year versus over the 7 year Follow-up Patients

Abstract

Purpose: To compare the 3 year and over the 7 year results after long-segment posterolateral fusion and to analyze the changes of adjacent segments and the changes according to the segmental lordosis angle of the fusion segments. Materials and Methods: A retrospective review was carried out 62 patients of long segment fusion for 7 years follow up and compared that of the 3 year and over the 7 year results. The changes of adjacent segments were evaluated by simple radiography for disc space narrowing, traction spur, endplate sclerosis and vacuum phenomenon. In last follow-up, segmental lordosis angle of fusion level was evaluated by Gelb,s criteria and clinical results were analyzed by Katz,s classification. Results: In the changes of adjacent segments, disc space narrowing was increased 27.4% to 38.7%, traction spur was 22.6% to 35.5%, endplate sclerosis was 19.4% to 32.2% and vacuum phenomenon was 8.1% to 12.9%. The changes of adjacent segments were observed that from 3.4% to 20.7% in physiologic group and from 33.3% to 90.9% in un-physiologic group. The clinical results showed 83.9% satisfaction and 16.1% un-satisfaction.Conclusion: In long-term follow up of long-segment posterolateral fusion, physiologic segmental lordosis angle should be preserved for decrease of changes of adjacent segments in long-segment posterolateral fusion.