Factors Predictive of Adjacent Segment Disease after Lumbar Spinal Fusion.

October 2, 2019

OBJECTIVE:

Adjacent segment disease (ASD) is a long-term complication of lumbar spinal fusion. This study aims to evaluate demographic and operative factors which influence development of ASD after fusion for lumbar degenerative pathologies.

METHODS:

A retrospective cohort study was performed on patients undergoing instrumented lumbar fusion for degenerative disorders (spondylolisthesis, stenosis, or intervertebral disc degeneration) with a minimum follow-up of 6 months.

RESULTS:

568 patients met our inclusion criteria; 29.4% of patients had developed surgical ASD. Median follow-up was 2.8 years. Multivariate logistic regression analysis showed that decompression of segments outside the fusion construct had higher (Odds ratio (OR) = 2.6; p < 0.001) and undergoing fusion for spondylolisthesis had lower (OR, 0.47; p = 0.003) ASD.

CONCLUSIONS:

Results of our study shows that the most important surgical factor contributing to ASD is decompression beyond fused levels. Hence, caution should be exercised when decompressing spinal segments outside the fusion construct. Conversely, spondylolisthesis patients had the lowest ASD rates in our cohort.