Evaluating the accuracy of three-dimensional surface-imaging for circumference analysis of the thigh

Three-dimensional (3D) surface-imaging is an increasingly popular and useful tool in surgical planning and evaluation. These systems are used for anthropometric measurements of the face, breast and upper extremity. Its accuracy has, however, not yet been evaluated for the thigh. This could prove useful in the evaluation of autologous breast reconstructions using fasciocutaneous tissue of the thigh, such as the profunda artery perforator (PAP) flap.

Thirty-five patients who underwent PAP flap surgery and 35 healthy controls were included. Thigh circumferences were measured using a flexible measuring tape at pre-defined levels. 3D images of the thigh were taken with the Canfield Vectra XT and fused to create 3D reconstructions. 3D circumferences were measured using the Vectra Analysis Module. Measuring tape and 3D circumferences were compared for mutual agreement.

Thigh circumference measurements by measuring tape correlated excellently with 3D measurements (r = 0.999). Bland-Altman plots demonstrated good agreement with a mean difference of -1.2 mm between the measuring tape and 3D measurements. The mean relative difference of both methods was -0.24%. Paired t-tests showed no significant statistical differences between the measuring tape and 3D circumference measurements in legs that underwent PAP flap surgery and without.

Flexible measuring tape and 3D circumference measurements of the thigh show excellent correlation. Three-dimensional surface imaging can thus be used to measure thigh circumferences in both patients with and without prior surgery of the thigh.