Contrast enhanced ultrasound (CEUS) - an unique monitoring technique to assess microvascularization after buried flap transplantation.

Abstract

Incidence of patients requiring complex soft tissue or osseous reconstruction has dramatically increased. However most of the monitoring systems have limitations in tissue penetration and are not able to detect microvascular complications after transplantation of so-called buried-flaps, that have no contact to the surface.Aim of the study was to assess contrast enhanced ultrasound (CEUS) as monitoring tool after buried flap transplantations. 20 patients were examined after buried flap transplantation using CEUS. Quantitative perfusion analysis (TIC) was performed with an integrated perfusion software using stored cine-loops. Two perfusion-parameters, time to PEAK (TtoPk) and area under the curve (Area), were evaluated using TIC analysis. Minor complications were observed in 3 patients. In these patients a delayed contrast agent wash-in and wash-out was observed. Additionally the perfusion values TtoPk (sec.) and Area (relative Units) were clearly different in the patients with minor complications: TtoPk: 32.0 sec; Area 425.5 rU (without complication), TtoPk: 38.6 sec.; Area: 18.3 rU (wound healing disturbance) and TtoPk: 14.4 sec.; Area: 105.9 rU (hematoma). As CEUS can assess microvascularization almost depth-independent, CEUS is an unique method to assess global flap perfusion after buried flap transplantation.