Microvessel Visualization in Designing Perforator Flaps

High-resolution ultrasound for visualization of microvessels has become a powerful instrument for microsurgeons. Ultrasound devices have improved in quality immensely propelling blood flow imaging and characterization of perforating vessels (Tashiro et al., J Plast Reconstr Aesthet Surg 69(3):346–50, 2016, Su et al., Plast Reconstr Surg 131(1):80–93, 2013). Vascular structures of 0.2 mm and less in diameter may be detected with correct settings (Su et al., Plast Reconstr Surg 131(1):80–93, 2013, Schwabegger et al., Plast Reconstr Surg 104(6):1656–65, 1999, Yamamoto et al., Plast Reconstr Surg 147(3):470–8, 2021). Real-time imaging may now visualize the suprafascial architecture of microvessels and subbranches (Vaienti et al., Arch Plast Surg. 47(2):165–70, 2020, Visconti et al., Arch Plast Surg 47(4):365–70, 2020). Anatomic and hemodynamic data of vessels of the donor as well as recipient sites of flap reconstructions may be assessed (Vaienti et al., Arch Plast Surg. 47(2):165–70, 2020, Gravvanis et al., In Vivo 27(3):371–5, 2013). Evaluation of qualitative parameters as number, precise location, and course of perforators is simplified. Quantitative parameters as diameter and blood flow velocities of microvessels may be measured for a better understanding of flap physiology. Flow direction of arterial and venous vascular structures and turbulences may be visualized (Alzaraa et al., Hepatol Res 43(8):809–19, 2013, Hallock, Clin Plast Surg 30(3):347–57, 2003). Device settings for microvessel imaging are of supreme importance for a successful ultrasound analysis (Kehrer et al., Microsurgery 40(7):750–9, 2020, Cho et al., J Reconstr Microsurg 36(7):514–21, 2020). Besides hardware and software trimming, appropriate selection of various ultrasound modes is compulsory (Kehrer et al., J Plast Reconstr Aesthet Surg 73:1081–90, 2020). The following chapter aims to elucidate relevant ultrasound device properties and technical aspects for microvessel imaging for a simplified design of perforator flaps. It also suggests a structured sequence for optimal perforator mapping.