13. Association between dynamic instability and muscle health change in patients with L4-5 degenerative Grade I spondylolisthesis and operative spinal stenosis

Abstract

BACKGROUND CONTEXT

Degenerative spondylolisthesis at the L4-5 level is a prevalent spinal condition often requiring surgery. Chronic low back pain has been strongly associated with paraspinal muscle deterioration, including multifidus atrophy, and poorer muscle health has been linked to decreased quality of life. However, the connection between muscle degeneration and lumbar spine instability remains unclear, with contributing factors likely including age, altered biomechanics, and activity levels. Degenerative spondylolisthesis at L4-5 often requires surgery and is linked to paraspinal muscle atrophy and reduced quality of life. However, the impact of instability and alignment changes on muscle health remains unclear, particularly in severe cases. This study aims to address these gaps by investigating muscle health using advanced metrics to better understand its relationship with spondylolisthesis.

PURPOSE

This study aims to investigate the association between dynamic instability and muscle health changes in patients with Grade 1 L4-5 degenerative spondylolisthesis and operative spinal stenosis, enhancing our understanding of the pathophysiology of spondylolisthesis.

STUDY DESIGN/SETTING

Single-center retrospective cohort study.

PATIENT SAMPLE

The study cohort consisted of patients diagnosed with L4-5 spinal stenosis who underwent surgical intervention at the L4-5 level. The cohort was further stratified into two groups: those with L4-5 grade 1 spondylolisthesis and those without spondylolisthesis.

OUTCOME MEASURES

Difference in lumbar lordosis, L4-5 Cobb angle, anterior disc height, posterior disc height between flexion and extension, Goutallier classification, lumbar indentation value, BMI, and L4-5 paraspinal and psoas cross sectional area.

METHODS

Descriptive statistics were employed to determine L4-5 grade 1 spondylolisthesis, L4-5 spinal stenosis, and surgery involving the L4-5 intervertebral level. Patients were subdivided based on the presence of spondylolisthesis. Cross-sectional area normalized by body mass index (CSA/BMI) was quantified using ImageJ software. Measurement of lumbar lordosis, Cobb angle, and lumbar indentation value were recorded by radiographs. Statistical analysis was conducted using independent Student's t-test and bivariate analysis to compare the groups.

RESULTS

There were 101 patients included in our analysis. Fifty-two patients had Grade 1 degenerative spondylolisthesis. The spondylolisthesis group presented with significantly greater L4-5 lordosis in extension compared to the group without spondylolisthesis (23.69 ± 10.62 vs 20.22 ± 7.92, p = .044). However, the spondylolisthesis group also presented with significantly worse anterolisthesis in flexion (7.21 ± 3.66 vs 10.14 ± 23.53, p = .0002). There was no significant difference in absolute difference of lordosis and L4-5 segmental angle in flexion and extension between both cohorts. Through bivariate analysis, the results indicated a significant and negative correlation between psoas CSA/BMI and difference in lumbar lordosis (p = .0038, r = -.578) and Goutallier score and degree of lordosis and L4-5 Cobb angle (p = .00017, r = .798) in the spondylolisthesis cohort. Similar results were not significant in the nonspondylolisthesis cohort.

CONCLUSIONS

This study highlights a significant link between dynamic instability and muscle health in patients with L4-5 degenerative spondylolisthesis and spinal stenosis. Spondylolisthesis patients showed greater L4-5 lordosis in extension and worse anterolisthesis in flexion, with psoas muscle health negatively correlating with instability measures. These findings suggest muscle deterioration may contribute to the pathophysiology of spondylolisthesis, warranting further research to guide targeted therapies.

FDA Device/Drug Status

This abstract does not discuss or include any applicable devices or drugs.