Use of tonometry to assess lower extremity lymphedema.

Tissue tonometry was used to assess the outcome of microwave hyperthermia in treatment of 9 patients with lower extremity lymphedema. After microwave treatment, tissue tonicity of the lymphedematous leg returned toward normal. This improvement correlated with a reduction of leg volume and circumference, decrease in "inflammation" in the edematous subcutaneous tissue and clinical episodes of cellulitis. Possible factors involved in this shift in tissue tonicity toward normal include mobilization of excess fluid and plasma proteins from the interstitium, reduction in microvascular cellular infiltrate and changes in the elastic and viscoelastic properties of matrix collagen, elastin and ground substance following hyperthermia.