VALIDITY AND INTRA- AND INTEROBSERVER RELIABILITY OF AN INDIRECT VOLUME MEASUREMENTS IN PATIENTS WITH UPPER EXTREMITY LYMPHEDEMA
Abstract
We investigated a method of indirect volume measurement that utilized surface measurementsand a simplified formula derived from the formula for a frustum (Sitzia’s method) to determine limbvolumes in patients with breast cancer-related lymphedema of the upper extremity. Repeatedmeasurements of upper-extremity limb volume were obtained by two observers on both upper extremitiesof 30 women with unilateral lymphedema. Volume was calculated using a simplified formula andcompared with water displacement method as a gold standard. Indirect volume determination usingSitzia’s method is comparable with the water displacement method, has comparable intra- andinterobserver reliabilities, and can be used for diagnosis and follow up measurements of lymphedema.Indirect volume determination using surface measurements at 8 cm intervals is only suitable for followup measurements. The methods should not be used interchangeably.