ASSESSMENT OF BLOOD FLOW IN THE ROTATOR CUFF BY LASER DOPPLER FLOWMETRY

Abstract

Aim: Despite many studies the implications of perfusion and blood flow abnormalities in the rotator cuff (RC) in vivo are not clearly understood. Laser Doppler Flowmetry (LDF) is an established technique for the measurement of perfusion in tissue, which has been applied in animal and human studies. This study aims to evaluate Laser Doppler Flowmetry (LDF) as a technique for the assessment of blood flow in the normal and diseased RC.

Methods: With Ethics committee approval and informed consent patients undergoing arthroscopy for impingement or cuff tear (diseased cuff) and instability (normal cuff – BO) were recruited. Following diagnostic arthroscopy and bursoscopy measurements of the LDF in the RC tear were made at 6 points. Five of these were in the cuff over a 4 cm. 2 are from the insertion at the greater tuberosity and one in the deep surface.

Diseased RC were sub grouped into mild (B1), moderate (B2) and severe (*B3 – cuff tear) impingement grades (Copeland – Levy Classification). The arthroscopy, grading, and probe placement were made by the senior authors. LDF flux (LDFf) was recorded over 30 seconds at each measurement point. The mean of these readings was then calculated (LDF flux – an arbitrary unit of measurement of the perfusion).

Results: 35 patients were recruited. 210 measurements were recorded, in 6 anatomical locations. The mean LDFf was 34.1 in diseased RC and 55.3 in normal RC (p=0.0002). The mean LDFf was 52.2 in severe (RC tear) impingement and 30.3 in mild and moderate impingement’s (p< 0.0001).

The LDFf was lowest in the moderate grade with a significant increase at the edges of a cuff tear.

Conclusion: Preliminary recording of LDFf show changes are in keeping with current knowledge of the pathology. LDFf decreases with advancing impingement. There is an increase in LDFf at the edges of RC tears. This might reflect a reparative response.