Neuromuscular ultrasound imaging in low back pain patients with radiculopathy.

BACKGROUND

Patients suffering from chronic low back pain with associated radiculopathy (LBP-R), or sciatica, experience neuromuscular symptoms in the lower back and leg; however, research to date has focussed solely on the lower back.

OBJECTIVES

To expand neuromuscular research of LBP-R patients into the lower limb, using ultrasound imaging.

DESIGN

Case control study comparing LBP-R patients to matched healthy controls.

METHODS

LBP-R patients with disc bulge or herniation (L3/L4 to L5/S1) resulting in unilateral radiculopathy (n = 17) and healthy matched controls (n = 17) were recruited. High-resolution ultrasound imaging was used to investigate sciatic nerve structure, as well as the quality (relative magnitude of fat/fibrosis infiltration) and contraction (muscle thickening) of associated musculature in the lower back (paraspinals) and lower limb (biceps femoris, gastrocnemius, soleus).

RESULTS

LBP-R patients had swollen sciatic nerves (increased cross sectional area), but this was not associated with evidence of reduced lower limb muscle quality. As compared to controls, LBP-R patients demonstrated less soleus muscle thickening during submaximal contraction; however, there were no impairments in the hamstring or lower back musculature.

CONCLUSIONS

Ultrasound imaging was an effective method to detect sciatic nerve swelling in mild to moderately affected LBP-R patients. Nerve swelling was not associated with poorer muscle quality, nor consistently impaired muscle contraction.