3D color doppler ultrasound for postoperative monitoring of vascularized lymph node flaps

Vascularized lymph node transfer (VLNT) is a relatively well-established microsurgical treatment for lymphedema that is especially beneficial for advanced cases in which lymphovenous anastomosis is not indicated due to lymphatic vessel sclerosis. When VLNT is performed without a skin paddle, such as a buried flap, the possibilities for postoperative monitoring are limited. The aim of our study was to evaluate the use of ultra-high-frequency color Doppler ultrasound with 3D reconstruction in a pedicled axillary lymph node flap.

Flaps were elevated in 15 Wistar rats based on the lateral thoracic vessels. We preserved the axillary vessels to maintain the rats' mobility and comfort. The rats were divided into three groups as follows: Group A, arterial ischemia; group B, venous occlusion; and group C, healthy.

Ultrasound and color Doppler scan images revealed clear information on flap morphology changes and pathology if it was present. Surprisingly, we detected venous flow in group A rats, supporting the pump theory and venous lymph node flap concept.

We conclude that 3D color Doppler ultrasound is an effective method for monitoring buried lymph node flaps. 3D reconstruction makes it easier to visualize the flap anatomy and detect pathology if it is present. Moreover, the learning curve for the technique is short. Our setup is user-friendly even in the inexperienced hands of a surgical resident, and images can be reevaluated at any time if necessary. The use of 3D reconstruction removes the complications associated with observer-dependent monitoring of VLNT.