Edema and leg volume: methods of assessment.

Various techniques may be used to assess leg edema. The value of these investigations has been discussed in depth in the consensus statement made in Vaux de Cernay in 1997 and supported by Servier Research Group. These techniques can be classified into three groups: The most simple is leg circumference measurement, which can be assessed by a tape measure, or more rigorously with a Leg-O-Meter. This device is a cheap and reproducible method that has been validated and that takes into account the height at which the circumference has been measured. However, circumference measurement is not always correlated with leg (including foot) volume measurement. The second group of techniques assess leg volume. The most simple method is water displacement volumetry, which has been validated in terms of reproducibility. Several other devices have been used: optoelectronic methods, computed tomography, magnetic resonance imaging (high resolution), dual X-ray absorptiometry. These methods are expensive and not all of them have been validated, but these might be the future investigations of choice. Some other investigations assess immediate variations in volume such as water displacement using dynamic foot volumetry, rheoplethysmography, strain gauge plethysmography, and air plethysmography. The assessment made by these methods (using postural, dynamic, or compressive maneuvers) is more an assessment of the venomuscular pump and/or venous outflow than volume assessment. In conclusion, edema, an early and frequent sign of chronic venous insufficiency (CVI), can be precisely measured by several methods. This measurement can be considered one of the most objective ways of assessing treatment efficacy in CVI-associated edema.