Abdominal aortic calcification is independently associated with increased atrophy and fatty infiltration of the lumbar paraspinal muscles: a retrospective cross-sectional study.

BACKGROUND

Aortic abdominal calcification (AAC) is associated with spine-related conditions, such as lower back pain and reduced bone mineral density. Similar to peripheral vascular disease, AAC possibly reduces blood flow to the lumbar posterior paraspinal muscles (PPM) which may lead to atrophy and increased fatty infiltration.

METHODS

Imaging of patients with lower back pain was analyzed. AAC was assessed on lateral lumbar radiographs according to the Kauppila classification. The cross-sectional area of the PPM was measured on a T2-weighted axial MRI sequence and the functional cross-sectional area (fCSA) and fatty infiltration (FI) were calculated with custom software. The association of AAC and FI as well as AAC and fCSA was assessed by multivariable linear regression, adjusted for age, sex, body mass index (BMI), diabetes, and smoking.

RESULTS

Two hundred and thirty patients (47.8% female) with a median age of 60 years (IQR 48-68) were analyzed. In patients, without AAC the median FI of the PPM was 33.3% (IQR 29.1-37.6%), compared to 44.6% (IQR 38.5-54.3%) in patients with AAC (p < 0.001). In the multivariable linear regression, both fCSA and FI of the PPM were significantly and independently associated with the degree of AAC (p = 0.037 and p = 0.015, respectively).

CONCLUSIONS

This is the first study to demonstrate a significant and independent association between AAC and PPM morphology. The results of this study improve our understanding of the interaction between AAC and spinal musculature, with AAC being a reason for atrophy of the PPM.