HAND VOLUME ESTIMATES BASED ON A GEOMETRIC ALGORITHM IN COMPARISON TO WATER DISPLACEMENT

Abstract

Assessing changes in upper extremitylimb volume during lymphedema therapy isimportant for determining treatment efficacyand documenting outcomes. Although armvolumes may be determined by tape measure,the suitability of circumference measurementsto estimate hand volumes is questionablebecause of the deviation in circularity of handshape. Our aim was to develop an alternativemeasurement procedure and algorithm forroutine use to estimate hand volumes. Acaliper was used to measure hand width anddepth in 33 subjects (66 hands) and volumes(VE ) were calculated using an ellipticalfrustum model. Using regression analysis andlimits of agreement (LOA), VE was comparedto volumes determined by water displacement(VW), to volumes calculated from tape-measuredetermined circumferences (VC), and to atrapezoidal model (VT).VW and VE (mean±SD) were similar(363±98 vs. 362±100 ml) and highly correlated;VE = 1.01VW -3.1 ml, r=0.986, p<0.001,with LOA of ±33.5 ml and ±9.9 %. In contrast,VC (480±138 ml) and VT (432±122 ml) significantlyoverestimated volume (p<0.0001).These results indicate that the ellipticalalgorithm can be a useful alternative to waterdisplacement when hand volumes are neededand the water displacement method is contraindicated,impractical to implement, too timeconsuming or not available.