| Retrograde island flap was called as the reverse blood island skin flap, which is aspecial type of the distally based skin flap. It points that both the blood supply and venousreturn is reverse to the physiological direction in the flap. According to definition of thereverse island skin flap, early blood circulation of reverse island skin flap has the featuresof "perfusion easy and backflow difficult". Therefore, the academic experts focus on thevenous problem in the beginning of the formation of the retrograde island flap. The venousmechanisms of reverse island skin flap are "venous flap failure" and "maze backflow" atpresent mainly. Some scholars believed that venous obstacle is the main necrosis cause ofskin flap, and design to reduce congestion vein from different aspects. But it is notuncommon that arterial insufficiency is the reason of clinical flap necrosis. Arterialinsufficiency is still a major cause of flap necrosis. After arteriovenous bypass reverseisland skin flap increases the flap pressure through the high pressure of arterial perfusion,which promotes blood supply to the flap, venous reflux and the flap survival area. In thisstudy, the experimental study research on the promotion of the venous countercurrent andthe bypass the arterial blood to the vein.Objective:The difference of each group was compared after the different treatment of the arteryand vein in the flap. Necrosis reasons of the reverse island skin flap or a distally based flapwere explored. We increased the arterial blood of the flap by arteriovenous bypass, andexplored the effects of the flap survival area, which aimed to improve the flap survival rate.Methods:Animal experiment: A total of40New Zealand white rabbits, aged6months andweighing,2.5~3.0kg. Male or female, were randomly divided into four groups (n=10).Medial leg design includes the saphenous nerve and sphenoid artery retrograde island flap,an area of12.0cm×7.0cm, pedicle width0.5cm flap aspect ratio of about2:1. Cut the flapsurrounding skin, revealing the hidden arteriovenous and the great saphenous vein, nearlyflap ligation of the depth of vein from near and far off from the deep fascia flap until thepedicle, during which the traffic branch. Placed between the flap and the wound at the bottom of the translucent film barrier,3-0silk interrupted sutures in situ.40rabbits wererandomly divided into four groups: A control group, made simple retrograde island flap,flap of the proximal end of the pedicle without any treatment; group B, the flap proximalend of the great saphenous cut off the vein, the saphenous vein and the saphenous artery,will cut off the saphenous artery proximal lumen cross-section is trimmed to1/2, with theflap side of the saphenous vein end to end anastomosis, saphenous vein ligation. C group,flap the proximal end of the great saphenous vein and the hidden action, cut off the vein,saphenous artery lumen cross-section is trimmed to1/2, and the other ends of thesaphenous artery anastomosis to retain part of the arterial perfusion within the flap, a largesaphenous vein ligation of the blood by reverse accompanying vein and great saphenousvein reflux; Group D, flap of the proximal end of the great saphenous vein and the implicitand vein cut, ligation of the saphenous artery, will cut off the saphenous vein lumen facetrim1/2, and then the other end of the saphenous vein stump anastomosis, retained thevenous drainage channels within the flap.The color and swelling of the flap were observed after surgery. The filling of the flapblood flow distribution and blood were observed by radionuclide scanning. Pending flapsurvival area of stability, through the grid method to calculate the area of flap survival andnecrosis to calculate the percentage of survival area, groups were compared flap survivalarea of the average percentage of distribution. Microscopic internal growth was observedby histological observation.Results:1. Control group A can be found that gradually filling inside the vein after the surgery,with the blood poured, the vein gradually expanded and even engorgement, was darkpurple cord-like vein, the flap edge is gradually oozing dark red vein blood. Graduallydarken the color of the flap, a week after all the three cases of flap necrosis, the time ofenumeration, removed and completion of the pilot; group B: postoperative release thevascular clip, the saphenous vein is rapidly filling, the saphenous vein engorgement. Earlypostoperative flap color dark red (3d),3d starting to turn red, no blisters, nine cases ofcompleted experiments, including one cases of infection of necrosis, all statistics whenremoved; in group C: Postoperative peripheral arterial perfusion, blood filling the insideflap, flap in the congestion state, and venous engorgement. The second postoperative dayflap distal darker, and then observe the original darker part of the black scab, and proximalto the flap extension to10days after flap necrotic area does not change, completion ofExperiment8cases of infection in1case, all necrosis. Group D: venous partial ligation,making some of the blood can still be in accordance with the original vascular channels back to the venous drainage within the flap open, swelling of the lighter to complete theexperiment of eight cases, infection in1case, the time of enumeration and removed onecases of complete necrosis.2. Radionuclide scan found all the flap in group B nuclide signal a more extensivearea of radionuclide distribution to group A in the control group, radionuclide distributionarea than the minimum, even without the existence of the radionuclide signal.3. Control group A: The last three cases of infection and necrosis statistical removedcompletion of the pilot of seven cases, the average flap survival rate was56.30%; group B:a week after the9cases of completed experiments,1case of necrosis, and flap survivalrate an average of82.27%; Group C: completion of the pilot eight cases, all of necrosis,infection in1case statistics excluded from the average of the flap survival rate was66.26%;Group D: the completion of the experiment eight cases, infection in1case. All necrosis is1case. The flap survival rate of an average is67.39%. Flap area survival rate in each groupwere: Group B> Group D> group C> group A, the comparison between group B and A, Cand D, three groups were statistically significant (p <0.05). In group B and group Asignificant statistical significance (p <0.01). C, D, no significant statistical difference.4. Control group A: the regeneration of capillaries less under the microscope, evensome viable part of the organization can be seen more fibrous scar tissue. Group B: ahigher capillary density, and uniform distribution of blood cells within the capillaries in thelumen. Group C: capillary blood cell more, but because of poor venous return, showingcongestion like blood cell agglutination. Group D: blood cell agglutinated, but less thanthat of group B blood cells within the lumen.Conclusion:Arteriovenous bypass can increase the blood supply to the flap and promote venousreturn of reverse island skin flap to some extent, which expands the area of flap survivaland improves the skin flap survival rate. |
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