Abstract

Background: The skin’s condition is altered in lymphedema patients, and evaluating this change is important. Some noninvasive methods for evaluating skin condition have been reported, especially in upper limb lymphedema. However, evaluating the skin in lower limb lymphedema remains challenging and is often limited to palpation. We aimed to develop a noninvasive skin evaluation method for lower limb lymphedema patients.

Methods and Results: Twenty-five lower limb lymphedema patients were included. Skin induration and elasticity were measured using IndentometerIDM 400 and Cutometer MPA580. The relationship between the properties of skin from the healthy forearm and thigh, those of the affected thigh, and age was analyzed. Predicted skin induration age (IA) and elasticity age (EA) were calculated from the forearm, whereas actual values were calculated from the thigh, and the differences (DIA and DEA) were assessed. Patients were classified according to the International Society of Lymphology clinical staging system, and the differences in DIA and DEA were analyzed among the three groups (healthy, stage I/IIa, and stage IIb/III). Skin biopsy was performed in five unilateral lower limb lymphedema patients, and the dermal elastic fiber area was determined using microscopy with Elastica van Gieson staining. DEA significantly increased with disease progression, but DIA did not change significantly. Microscopy revealed elastic fiber filamentous changes, with decreased elastic fiber areas in lymphedema-affected skin.

Conclusion: To our knowledge, this is the first report to evaluate lower limb skin elasticity in lymphedema quantitatively and noninvasively. DEA is useful for evaluating skin condition progression in lymphedema patients.

Main findings

• This study consisted of two parts. The first part evaluated skin induration and elasticity. In the second part, skin tissue samples were obtained from patients with lymphedema and the elastic fibers in the lymphedema skin were evaluated histologically using microscopy.
• Skin induration was evaluated by the Indentometer. IDM 400 (Courage+Khazaka Electronic GmbH, Cologne, Germany). After placing the probe on the skin, the device measures how much the pin-shaped indentometer probe displaces the skin. The penetration depth is measured, ranging from 0 to 3mm. The harder the skin, the less deep the displacement by the probe. Skin elasticity was measured using the CutometerMPA580 (Courage+Khazaka Electronic GmbH) Negative air pressure is created for 2 seconds in the device, and the skin is drawn into the probe from 0 to 2 seconds and released again from 2 to 4 seconds. Inside the probe, the penetration depth is determined by a non contact optical measuring system. The light intensity varies due to the penetration depth of the skin.