Primary lymphedema of the leg: relationship between subcutaneous tissue pressure, intramuscular pressure and venous function.

In eight patients with unilateral primary lymphedema, subcutaneous tissue and intramuscular pressure were measured in both legs using the slit-catheter technique. Venous function was assessed by venography, or Doppler or photoplethysmography. Both at rest and during exercise, subcutaneous tissue pressure was elevated in the lymphedematous leg (17.9 +/- 7.6 and 33.0 +/- 10.8 mmHg respectively) compared to healthy contralateral leg (0.4 +/- 2.6 and -0.6 +/- 3.6 mmHg; p less than 0.001). The intramuscular pressure in the anterior tibial compartment was also increased at rest and during exercise in the edematous leg (24.9 +/- 4.4 mmHg and 43.6 +/- 11.2 mmHg respectively) compared to control leg (9.6 +/- 5.6 and 25.8 +/- 10.00 mmHg). These findings suggest that derangements in both the superficial and deep lymphatic systems as well as venous dysfunction contribute to the clinical appearance of "primary lymphedema."