Experimental Studies Of Perforator Flaps In Hemodynamics

Objective : The purposes of these studies were toinvestigate the hemodynamic physiology for perforator flaps(PFs).Methods: 1. Hemodynamics in the superior epigastricarteries (SEAs) of 4 mature Wuzhisan pigs (male 2, female 2)were evaluated by Color Dopplex Ultrasonography (CDU).Angiographies were performed by the method of oxidized lead andglutin injection. Vascular constructions of SEAs were gainedby x—rays. Abdominal anatomies were done and documented. Thesedata were analyzed by paired t—test.2.6 same breed pigs were chose and the same sized bilateralabdominal flaps based on the SEAs, which were randomly dividedinto PFs group and myocutaneous flaps (MCFs) group, were usedas models of flap studies. Skin perfusions of both groups andnormal skin were detected by Laser Dopplex Perfusion Image(LDPI) at 2h, 1w, 2w, 3w, postoperatively. Hemodynamics in theSEAs (mean velocities, diameters) were evaluated by CDU,preoperatively, and 2h, 1w, 2w, 3w, postoperatively. Visualevaluation was documented in series. At 3w postoperatively, allanimals were sacrificed and the angiographies were performed.3. Two transverse abdominal skin flaps, based on the SEVsor its rectus abdominal muscle (RAM) perforators (C and D group)in other 4 animals, were designed and each pig was its owncontrol. At 2h, 1w, 2w, 3w postoperatively, skin paddle perfusions and blood stream velocities in SEAs were detectedby LDFI and CDU, respectively. Flap survival percentages werecalculated by grid method at 1w postoperatively. Animalsunderwent angiography at 3w postoperatively.Results: 1. Vascular series had good symmetries in bothsides except RAM perforators; The SEVs was dominant as comparedto the inferior epigastric vessels (IEVs). Choke anastomosisesbetween the SEAs and IEVs are found beween umbilicus and pubis.2. All flaps survived in PFs group and MCFs group. Edemaof PFs was severer than MCFs at 1w postoperatively. There weresignificant differences between PFs and MCFs, PFs and normalabdominal skin in skin perfusions at 2h, 1w, postoperatively(P＜0.05), and no statistical differences were observed at 2w, 3w,postoperatively (P＞0.05). Flow velocities and vasculardiameters in SEAs were remarkable reduction in PFs at 1w,postoperatively. Flowrates showed significant differencesbetween PFs and MCFs at 1w, 2w, 3w(P＜0.05).Velocitydecrementand diameter reducing were responsible for flowrate at 2h, 1wand 2w, 3w, postoperatively, respectively. Angiographies showedthat diameters in PFs were smaller than MCFs at 3w,postoperatively. The SEVs had smaller angiosomes and diametersin PFs than B MCFs.3. Edema of skin flaps based on the SEAs was severer thanskin flaps based on the RAM perforators, and skin perfusionsbetween two groups existed statistically differences at 2h, 1wpostoperative]y(P＜0.05). Skin paddle viability percentages at1w postoperatively, and skin perfusions at 2w, 3wpostoperatively, had no statistical differences(P＞0.05).Neovascularities were found in pedicles and flap bed by angiography at 3w postopertively.Conclusions: 1. Own control study of flaps base on the twosides SEAs is available in Wuzhisan pigs; Similar vessels shouldbe preserved when perforator flaps are developed in bothsides .2. PFs present a poor microcirculation mainly at lwpostoperatively, and are responsible for flap necrosis.Decreased diameter and lower velocity in PFs are responsiblefor flap failure when microvascular flap graft. Visualdifferences aren't significant at 2w, 3w, postoperatively.Angiosomes of the SEAs in PFs are reduced. 3. Too long pediclesor increased vascular diameter for anastomosis availablereduce flap perfusions at lw postoperatively, however, havelittle effect on flap survival. Flap perfusion depends on theflap construction and components and pedicle length have noeffect on flap physiology.