COMPARISON OF WATER OVERFLOW VOLUMETRY TO THE SEGMENT-ZONE METHOD FOR LIMB VOLUME DETERMINATION

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Objective. This study was conducted to compare foot/ankle volumes obtained by the Segment-Zone Method (SZM) to those obtained by water overflow volumetry (WOV) on the same subjects. Background. Measurement of limb volume is frequently employed to follow changes in both upper and lower extremity edema. Water overflow volumetry (WOV) is often chosen for this purpose. However, given that limb segments must be immersed, not every patient is a candidate for this procedure. Methods. Both SZM values (based on segment height, length, and breadth dimensions) and WOV values were acquired by separate investigators on 36 physical therapy students (25 males, 11 females). Geometric volumes were calculated using the formula for a standard wedge while water displacement volumes were determined by weighing the overflow and dividing by water density corrected for temperature. Results. A significant difference was found between the two methods (mean±SD; SZM = 884.8±158.6 ml, WOV = 958.2±167.7 ml; p < 0.01)). Data were further analyzed by dividing all subjects scores into 4 groups by appointment time (first 9, next 9, etc.) for analysis via ANOVA. No significant differences manifested as a function of appointment time for either geometric (p=.885) or volumetric (p=.499) groups. Conclusion. Although volume discrepancies were noted, both techniques correlated positively with each other (r= .71, p < 0.01). We therefore conclude either method can be used to follow foot/ankle edematous changes when serial trends, and not exacting volume calculations (i.e., in ml), are indicated. Grants. N/A