COLOUR DOPPLER ULTRASOUND IN THE ASSESSMENT OF LUMBAR SPINE BLOOD FLOW IN PATIENTS WITH LOW BACK PAIN

Abstract

Introduction: Duplex ultrasound has recently been used to demonstrate inflammatory hyperaemia in arteries supplying inflamed joints in RA, bursitis, and tendonitis. The technique has yet to be applied to examine blood flow in lumbar arteries in LBP patients, though we have previously shown its feasibility in healthy subjects. Our aim was to determine if there are differences in the flow characteristics of lumbar arteries in patients with LBP that may be reflective of pathology.

Materials and Methods: Sixty four patients with LBP (21–82 years) and 30 volunteers with no history of LBP (19–82 years) were studied. Sacral and lumbar arteries at L5 to L1 were identified and hemodynamic data was obtained using Duplex ultrasound. Angle corrected measurements of blood flow peak systolic velocity (PSV) were obtained at all lumbar levels and the aorta.

Results: Mean lumbar artery PSV was normalized with mean aorta PSV for patient and control groups. Reference range (mean ± 1.96SD) for normal lumbar artery PSV was defined from the control data and the proportion of patients with abnormally high PSV determined.

Discussion: Blood flow velocity in lumbar arteries of LBP patients is significantly higher compared with asymptomatic controls (p< 0.01). Approximately 40% of the LBP group have abnormally high lumbar artery flow velocity and the proportion of abnormal values increases at lower levels. Abnormally high velocity flow suggests the presence of an inflammatory component in the lumbar spinal structures. This technique has important applications in improving diagnostic specificity and assessing outcome of treatment in patients with LBP.