Early Adjacent Segment Degeneration after Short Lumbar Fusion

Abstract

Introduction Today in a review of the world literature there is no consensus about the main risk factor for the symptomatic adjacent segment disease, as well as the terms and conditions of its occurrence. Furthermore there are more and more questions about the reasons for the early development of ASD in the event of a short fixation, which according to some authors, should be associated with the wrong tactics of treatment and regarded as a complication of surgery. Material and Methods This study evaluated 146 patients who underwent one level 360° fusion lumbar surgery from 2005 to 2012 for the treatment degenerative conditions of the lumbar spine. It should also be noted, that patients with L5-S1 fusion were excluded from the study due to the peculiarities of the biomechanics of the segment. So we compare 2 groups according to the presence and extent of initial degenerative changes in the adjacent upper segment. These groups were similar of major risk factors for ASD, such as obesity, age, smoking, menopause, global balance disturbance. Patients in both groups had no significant differences in sex and age composition, the level of quality of life and daily physical activity. First group include 86 patients with no pre-existing or 1 to 3 stage degenerative changes by Pfirrmann modified, second group include 60 patients with initial adjacent disk degenerative changes of stage 4 and above according Pfirrmann modified classification. The average follow-up period was 42.2 months (range, 28–112 months). Results In the I group symptomatic ASD was found in 14 (16,3%) cases and ASD average development time was 35 (8–56) months. In the II group during the follow-up period 24 (40%) patients had ASD with average development time 21,5 (3–46) months. Symptomatic adjacent segment pathology was significantly more frequent in the II group ( p < 0.05). The timing analysis of the symptomatic ASD showed statistically significant data on the earlier development of this disease in the second group ( p < 0.05). Conclusion Patients with pre-existing degenerative changes in adjacent levels above stage 3 by Pfirrmann must be assigned to a high risk group for early ASD development even in the short lumbar fusion.