Background

Volume fluctuations dramatically affect the daily fit and function of amputees’ prosthetic limbs.  Prosthetists have experiential knowledge of patient volume fluctuations; however they rarely have access to quantitative evidence.  Information regarding volume fluctuations is crucial when determining prosthetic socket design, component selection, and rehabilitation regimens.  A collaboration between the Human Dimensioning© Lab (HDL) and Dan Rowe and Associates, a community prosthetic and orthotic provider quantified volume data of individual residuum anatomy.  

 Method 

The project used a 3-dimensional optical body scanner and point cloud digitizing technology, currently used for apparel design, to quantify the daily residuum volume fluctuations in three lower limb amputees.  Utilizing the HDL design resources, three amputees were scanned three times at four intervals over a six-hour period.  The scans were analyzed using Polyworks® software.  Each group of three scans was meshed into an average and each of the four averaged scans was compared to the amputee’s remaining three averaged scans.  

Results

The results document the changes in volume of the subjects’ residuum over the six-hour period.  The subjects experienced a range of volume fluctuations from 0.5% to 7.5% of total volume.  To validate the method, scanned volume measurements were compared to a simple water displacement measurement.  The results from the scanning method and displacement method differed between .71% and 1.16%. The magnitude and period of fluctuation were not consistent between the subjects.

Conclusion

Presently, little is known of the magnitude of short-term volume fluctuations, nor is it known if shape changes accompany short-term volume changes.  This design and medicine collaboration provides a platform for compiling accurate and consistent residuum volume data and shape characterization.  The method has the potential to affect prosthetic limb design and fit.