Preliminary Exploration: When Angiosome Meets Prefabricated Flaps

Abstract

The best known limitation to the use of prefabricated flaps is their limited survival area. One explanation for this is insufficient neovascularization. However, blood flow of prefabricated flaps is through their innate vascular network. This could lead one to conclude that angiosomes may impede blood perfusion. This study aims to settle this contradiction between theory and clinical practice. We performed a two-stage operation of a prefabricated abdominal flap in a rat model. The rats were divided into five groups ( = 6/group). Group A: fixed pedicle at a horizontal angle; Group B: fixed pedicle at an oblique angle; Group C: fixed pedicle at a vertical angle; Group D: fixed pedicle in the same position as Group A; and Group E: axial flap. Groups A and B were prefabricated for 2 weeks and Groups C and D were prefabricated for 3 weeks. Macroscopic appearance was noted, and analysis of near-infrared fluorescence imaging and capillary density was performed. There was no significant difference in the flaps' survival area between Groups A and B. Group D had a significantly larger survival area when compared with Group C. The boundary between two angiosomes (medioventral line) seemed to limit the indocyanine green perfusion in Groups B, C, and E, while in Groups A and D, no such limitation was seen. Capillary density was positively correlated with neovascularization time. Angiosomes impede blood perfusion in prefabricated flaps. Cross-bound neovascular vessels nourish the flap, thus overcoming the limitation of choke vessels.

Activation of TRPV4 Increases Neovascularization of Rat Prefabricated Flaps

“…Vasodilation via nitric oxide might affuse impeded blood perfusion via angiosomes in prefabricated flaps. 17 In addition, the areas of satisfactory neovascularization detected by FLPI before the second stage operation corresponded with high similarity to the final survival area within the flaps. Therefore, additional 4αPDD injections into areas with insufficient neovascularization after the second stage might be a rescuing procedure for Fig.…”

“…In the tissue of the prefabricated flaps, VEGF-expression level was significantly different among the three groups, with the 4αPDD group being the highest and the RR group being the lowest (4αPDD vs. control: 44.32 AE 9.24 ng/g vs. 23.54 AE 2.44 ng/g, p < 0.05; control vs. RR: 23.54 AE 2.44 ng/g vs. 17.95 AE 4.88 ng/g, p < 0.05; ►Fig. 5).…”

Near-infrared fluorescence image-guidance in plastic surgery: A systematic review

“…In the described experiments, hand-held imaging systems and microscopes with an integrated NIRF were equally divided for imaging. There were four different hand-held systems (PDE n = 13, Visionsense n = 1, Fluobeam n = 2, and HyperEye n = 1) [ 7 – 19 , 44 – 46 , 49 ], one non-hand-held system (FLARE n = 8) [ 36 – 43 ], and three types of microscopes with an integrated NIRF (SPY n = 16, LEICA n = 2, and Pentero n = 1) [ 20 – 35 , 47 , 48 ] suitable for fluorescence image guidance. In one study, a prototype was used which was not further specified [ 51 ]; three articles unfortunately did not state what kind of imaging system was used [ 52 – 54 ].…”

“…Currently, the maximum penetration depth of NIRF visualization of ICG or MB is limited to 1.0–1.5 cm. The use of ICG was described in 44 articles [ 7 – 39 , 41 – 51 ], thereby making it by far the most commonly administered dye. ICG was injected either subcutaneously in order to visualize superficial lymphatic vessels (i.e.…”

“…NIRF angiography, after intravenous dye administration, was reported in 32 articles. The majority ( n = 24) [ 7 , 8 , 10 , 11 , 15 , 20 – 22 , 24 , 27 , 29 , 32 , 35 , 36 , 40 – 44 , 48 – 51 ] used NIRF to assess tissue perfusion in (free) flap surgery; the remainder focused on the perioperative assessment of mastectomy skin flap perfusion [ 32 – 34 ], bone perfusion [ 37 ], abdominal wall perfusion in abdominal wall reconstruction [ 23 , 28 ], and perfusion of a composite allograft [ 25 , 38 , 39 ]. See Table 4 .…”