Degenerative Changes of Adjacent Segment after Anterior Cervical Discectomy and Fusion / 대한척추외과학회지

STUDY DESIGN: A retrospective radiologic analysis of 34 patients OBJECTIVES: To evaluate the factors influencing the radiographic degenerative changes in the adjacent segments in one-level ACDF SUMMARY OF LITERATURE REVIEW: There is a 25% incidence of adjacent segment degeneration after 5 years. MATERIALS AND METHOD: From 2002 to 2005, 34 patients (male 23, female 11) underwent anterior cervical spine fusion using a cage or bone block for degenerative cervical spine. The mean age of the patients was 51 years and the mean follow-up period was 24 months. The degenerative findings of the upper and lower adjacent segment were measured from the pre-operative MRI. The fused segment curvature, disc heights of the adjacent segments, displacement of the vertebral bodies and angular mobility in the adjacent segments were measured from the pre-operative and final follow-up lateral views in the neutral position, in both flexion and extension. RESULTS: Degenerative changes in the adjacent segments were observed in 19 of the 34 patients. The group with degenerative changes showed significantly more lordotic angular loss of the fusion segments (11.9+/-3.1degrees) at the follow-up observation than the group with no degenerative changes (9.0+/-1.1degrees) (p=0.04). The group with degenerative change showed a significantly larger increase in disc height of the fusion segments (2.8+/-0.2 mm) at the follow-up observation than the group with no degenerative changes (2.2+/-0.3 mm) (p=0.02).The group with a Grade IV or higher level of pre-operative disc degeneration showed more degenerative changes in the adjacent segments than those with Grade III or lower. CONCLUSIONS: It is important to preserve the lordotic angle of fused segments and avoid excessive increases in disc height. The recurrence of the neurological is not associated with the preoperative adjacent segmental degenerative changes in ACDF.

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

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.

The Changes of Adjacent Segments after Fusions (above 3-levels to L5) in Degenerative Lumbar Spinal Disorders / 대한척추외과학회지

STUDY DESIGN: A retrospective study. OBJECTIVE: To evaluate the usefulness of MRI grading of disc degeneration in determining whether L5-S1 fusion is necessary in degenerative lumbar spinal disorders. SUMMARY OF LITERATURE REVIEW: Changes in adjacent segments are not well understood, after floating fusion has been performed. MATERIALS AND METHODS: We reviewed 16 surgical cases of degenerative lumbar spinal disorders from July 1996 to February 2000 with an average follow-up of 41 months. Fusion was done in patients without instability, pathology and narrowing of L5-S1. We measured the disc degeneration of adjacent segments in preoperative MRIs using the Modified Pearce classification. In spine AP, lateral and flexion-extension radiographs, we measured disc height, angular motion and instability changes and correlated these with disc degeneration. RESULTS: Disc height changes decreased in the upper and lower adjacent segments and preoperative disc degeneration above grade IV, decreased more in lower adjacent segment. A statistical correlation was found between disc degeneration and disc height changes in the lower segment (P=0.046), but not in the upper segment (P=0.649). The angular-motion was unchanged in the upper and lower adjacent segments, and no statistical correlation was found between disc degeneration and angular-motion changes (P=0.819, 0.208). Postoperative instability was found in the upper adjacent segment in 2 patients, but no statistical cor-relation was found between disc degeneration and instability (P=0.083, P=1.000). CONCLUSION: L5-S1 might be saved when free of pathology, and when disc degeneration is below grade III and balanced sagit-tally. However, further study is needed because of the short-term follow up and low number of cases in this study.