Objective Assessment of Skin Changes in Lower Limb Venous Disease Using a Tissue Tonometer

Abstract

Background:

Chronic venous disease (CVD) of the lower limbs is a major problem in the western world with 1% of the adult population estimated to be affected at any one time. No objective method is currently available to assess the skin changes of chronic venous disease. We have devised a tissue tonometer to compare skin compliance in patients with venous disease with that in control subjects.

Method:

Eighty-six limbs of 69 patients (34 men, 35 women; mean age 62 years, range 28-90 years) with venous disease confirmed by duplex ultrasonography and 42 limbs of 37 normal controls (23 men, 14 women; mean age 42 years, range 20-90 years) were studied. Patients were assigned to one of three clinical groups based on the Clinical, (a) Etiological, Anatomical and Pathophysiological (CEAP) method of classification and grading of chronic venous disease in the lower limbs: C3, oedema; C4a, pigmentation alone; C4b, lipodermato-sclerosis (LDS). Normal controls were assigned C0. A 4 mm diameter plunger loaded with a 30 g weight was applied to the skin 5 cm proximal to the medial malleolus or over the most severe region of skin change. The movement of the plunger was measured for 5 min using a linear variable differential transformer position detector. The initial displacement of the plunger (within 1 s) reflects the compliance of the skin.

Results:

In C4b patients with LDS, skin compliance is substantially reduced (median plunger displacement in 1 s = 0.81 mm, interquartile range (IQR) 0.67–1.18) compared with C0 control subjects (2.85 mm, IQR 2.39–3.22) (p<0.0005, Mann-Whitney), C4a patients with pigmentation alone without LDS (2.35 mm, IQR 2.04–2.91) (p<0.0005, Mann-Whitney) or C3 patients with venous disease (2.49 mm, IQR 1.58–3.13) (p<0.0005, Mann-Whitney). There were no statistically significant differences between the C0, C3 and C4a groups.

Conclusion:

Tissue tonometry provides an objective means of assessing skin changes in patients with lower limb chronic venous disease. This may be a useful method of measuring skin compliance as a research tool but will have limited clinical application.