Tissue dielectric constant and circumference measurement in the follow-up of treatment-related changes in lower-limb lymphedema

BACKGROUND: Lymphedema of lower limbs is a chronic condition that requires life-long management. Therapeutic effect of complex decongestive physiotherapy (CDP) is most often followed by circumference measurements (CM). However, the CM measurements are not specific to interstitial tissue fluid and have problems in sensitivity and objectivity. The aim of present study was to evaluate the therapeutic effect of CDP with a new tissue water specific measurement technique, in patients with lower limb lymphedema (LLL). METHODS: A total of 17 patients with unilateral LLL (11 primary, 6 secondary lymphedema) were recruited in this study. CDP was applied for 5 days a week for 4 weeks. CM measurement of both limbs was performed at nine sites along limb by tape measure. Percentage skin water content (PWC) of thigh, calf and ankle was measured in affected lymphedema limb and contralateral limb with MoistureMeterD Compact (MMDC) device. Inter-limb PWC ratio was calculated by dividing affected side's PWC value with PWC of contralateral limb. Patients were asked to fullfill the Lymph Quality of Life Questionnaire. RESULTS: Significant reduction of circumference after CDP was detected at all nine measurement sites along lower limb (P<0.01). PWC measurements showed a significant decrease of skin tissue water at thigh, calf and ankle measurement sites after CDP (P<0.001). Inter-limb PWC ratios demonstrated significant reduction of edema between affected and contraletral limbs post-treatment (P<0.003). CDP also increased the quality of life (P=0.006). CONCLUSIONS: CM and PWC measurements reflected a positive effect of CDP in patients with LLL. Both absolute PWC values and inter-limb PWC ratios were meaningful tools to follow the effect of therapautic intervention. Compared with CM measurements the TDC technique offered easier, quicker, objective and more practical measurements for routine assessments of LLL.