Risk Factors for Adjacent Segment Disease Development after Lumbar Fusion

Abstract

Study DesignRetrospective cohort study.PurposeTo identify factors which may be important in the occurrence of symptomatic adjacent segment disease (ASD) after lumbar fusion.Overview of LiteratureMany reports have been published about the risk factors for ASD after lumbar fusion. Despite on the great numbers of risk factors identified for ASD development, study results have been inconsistent and there is controversy regarding which are the most important.MethodsThis study evaluated 120 patients who underwent 360° fusion lumbar surgery from 2007 to 2012. We separated the population into two groups: the first group included 60 patients with long lumbar fusion (three or more levels) and the second group included 60 patients with short lumbar fusion (less than three levels).ResultsIn the first group, symptomatic ASD was found in 19 cases during the one year follow-up. There were 14 cases with sagittal imbalance and 5 cases at the incipient stage of disc degeneration according to the preoperative magnetic resonance imaging. At the three year follow-up, symptomatic ASD was diagnosed in 31 cases, of which 17 patients had postoperative sagittal balance disturbance. In the second group, 10 patients had ASD at the one year follow-up. Among these cases, preoperative disc degenerative changes were identified in 8 patients. Sagittal imbalance was found only in 2 cases with symptomatic ASD at the one year follow-up. At the three year follow-up, the number of patients with symptomatic ASD increased to 14. Among them, 13 patients had initial preoperative adjacent disc degenerative changes.ConclusionsPatients with postoperative sagittal imbalance have a statistically significant increased risk of developing symptomatic ASD due to an overloading the adjacent segments and limited compensatory capacities due to the large number of fixed mobile segments. In the case of a short fixation, preoperative degenerative changes are more important factors in the development of ASD.

Comparison of pedicle screw–based dynamic stabilization and fusion surgery in the treatment of radiographic adjacent-segment degeneration: a retrospective analysis of single L5–S1 degenerative spondylosis covering 4 years

“…28 In addition, a PT of > 21° and an SS of < 39° were perceived as factors for elevated risk for symptomatic ASD. 5 However, with cases of short fixation, Masevnin et al 21 failed to find statistically significant dependency between ASD and sagittal imbalance. In our study, there were no significant differences in spinal sagittal alignment between patients with and those without ASD in both groups.…”

“…Previous studies have documented a number of risk factors for ASD, such as age, multilevel fusion, BMI at admission, spinal sagittal alignment, and menopause. 14,21,23,24 A significant risk factor in determining ASD is preexisting degeneration at an adjacent level, including spinal stenosis and facet and disc degeneration. 15 Based on the hypothesis that degenerative aging factors have a greater influence than biomechanical factors, Li et al 17 claimed that adjacent segments with preexisting degeneration have a higher chance of ASD than do normal discs.…”

“…However, many reports have regarded the fusion technique as the most important risk factor for ASD. 1,13,14,21,23,26 A systematic review conducted by Lawrence et al 11 revealed that development of symptomatic ASD after lumbar fusion occurs at a mean annual incidence of 0.6%-3.9%. However, animal and cadaver studies have found increased range of motion and intervertebral stress in the adjacent segments after spinal arthrodesis.…”

“…29 Many studies have reported that fixated segments can predispose a patient to ASD. 21,23 In an attempt to address ASD associated with lumbar fusion surgery, dynamic surgical devices have been developed. Two widely used dynamic modalities are 1) a pedicle screw-based dynamic spinal stabilization system (PDS) and 2) total disc arthroplasty.…”

Is the Interspinous Device (Coflex) Outdated in the Treatment of Lumbar Spinal Stenosis? A Seven-Year Follow-up

“…The aim is to relieve clinical symptoms without considering the problem of fixed segment movement. Long-term follow-up reveals adjacent segment ROM increased to compensate for the lost ROM of the fixed segment, resulting in ASD [13][14][15][29][30][31][32][33]. Following improved knowledge of lumbar motion function, surgeons now consider how to treat lumbar degenerative disease while maintaining ROM, and dynamic stabilization has been developed and accepted.…”