Assessment of Piriformis muscle thickening in sciatica: Focused ultrasonographic evidence in patients with lumbar disc herniation

Abstract

Background

Low back pain (LBP) is a leading contributor to global disability, with lumbar disc herniation (LDH) being a common etiology. Despite the coexistence of LDH and piriformis muscle thickness, their potential relationship remains underexplored.

Objective

To investigate the correlation between LDH and piriformis muscle thickness in individuals diagnosed with LDH with no history of piriformis syndrome.

Methods

This cross-sectional study enrolled 107 participants diagnosed with LDH at the Neurology Outpatient Clinic in Siloam Hospital from September to November 2024. Piriformis muscle thickness was measured bilaterally using ultrasonography. Demographic data, clinical presentations, and magnetic resonance imaging (MRI) findings were collected.

Results

The mean age was 54.39 ± 12.69 years, with 58.9% being male. Affected sides demonstrated significantly increased piriformis muscle thickness compared to the unaffected sides (1.17 ± 0.22 cm vs. 0.93 ± 0.18 cm, p < 0.05). Age, weight, and body mass index (BMI) significantly influenced piriformis muscle thickness on the affected side. Age exhibited a negative correlation (r = −0.308), whereas weight and BMI demonstrated positive correlations (r = 0.218/0.192).

Conclusion

This study highlights significant thickening of the piriformis muscle on the affected side in patients with LDH, likely due to mechanical and inflammatory adaptations.