骨髓间充质干细胞促进兔预构皮瓣成活的实验研究

目的探讨新西兰大白兔骨髓间充质干细胞(BMSC)同种异体移植促进预构皮瓣的血管再生,从而提高预构皮瓣存活率的可能性。方法体外分离、培养、鉴定并标记新西兰大白兔的BMSC。在实验兔腹部两侧构建预构皮瓣,两侧皮瓣随机分为实验组和对照组,实验组在股血管周围经皮注射已标记的BMSC悬液,对照组注射等量生理盐水。注射后第7天追踪观察BMSC移植后的成活情况,术后第14天掀起以股动静脉为轴心血管的岛状皮瓣,分别对两组的岛状皮瓣进行BrdU/vWF的免疫荧光双标检测;对岛状皮瓣中的VEGF进行Western Blot半定量分析;岛状皮瓣形成后第7天,观察两组皮瓣的成活情况。结果 BMSC异体移植后成活良好;实验组皮瓣内VEGF蛋白表达量明显高于对照组;实验组皮瓣内BrdU标记阳性细胞胞浆内有vWF信号;将预构皮瓣制成岛状皮瓣后第7天,实验组和对照组皮瓣存活率分别为(93.1±2.6)%、(51.5±7.5)%,P<0.05。结论异体移植BMSC可促进预构皮瓣的血管再生,提高预构皮瓣存活率。     

预构皮瓣再血管化时间测定的动物实验研究

目的：动态观察预构皮瓣再血管化现象，确定预构皮瓣再血管化成熟的时间，为何时转移皮瓣提供指导依据。方法：以北京小型香猪为实验动物，转移胃网膜左血管预构左胸腹部皮瓣，以76％泛影葡胺连续数周做X线血管造影，观察血管在皮瓣内的形态学变化。结果：血管造影结果显示皮瓣在术后1周少量血管化，术后2周部分血管化，术后3周完全血管化，术后4周结果与术后3周无明显差异。结论：预构皮瓣再血管化成熟时间为血管转移术后3周，血管柬植入皮瓣3周后即可以植入血管束为蒂安全转移皮瓣。预构皮瓣再血管化现象是从植入血管束的远端开始，血管束的主干始终不发生再血管化现象。     

腺病毒-VEGF基因重组体促进预构皮瓣成活的实验研究

目的：应用大鼠预构皮瓣模型,探讨基因治疗技术产生的血管内皮生长因子促进预构皮瓣血管新生和皮瓣存活的可能性,为临床上寻找加速预构皮瓣成熟的新方法提供实验依据。方法：20只SD大鼠每只腹部两侧各构建一个预构皮瓣,共构建40个皮瓣,每只大鼠两侧皮瓣按随机原则进行不同的处理,分别归于实验组或对照组,每组各20个皮瓣。于大鼠腹部两侧各标记3cm×2cm矩形预构区,短边平行于腹股沟韧带,自尾侧短边中点向后纵向切开后肢皮肤,剥离出长约2cm的股动静血管束,远端结扎切断。在两侧预构区域的中轴线上,于真皮与肉膜层间各制作一皮下隧道,实验组的隧道壁皮下组织内注射携带有VEGF基因的腺病毒,同法向所有对照组的隧道壁软组织内注射等量生理盐水。将已剥离好的血管束向颅侧翻转置入相应皮下隧道内。所有已植入股血管的预购区域2周后均被制成以植入血管束为蒂的岛状皮瓣,从两组中各取一个皮瓣进行免疫组化染色,观察有无VEGF生成,其余岛状皮瓣均缝回原处。形成岛状皮瓣后第七天观察皮瓣存活及血管新生情况。结果：实验组与对照组的皮瓣平均存活率分别为（90．48±1．89）％、（69．75±2．36）％,其差异有统计学意义（P〈0．01）;血管放射显影图上,实验组植入血管周围见广泛白色显影,尤以血管两端明显,而对照组新生血管显影仅局限于植入血管周围;组织学切片显示实验组植入血管周围新生血管丰富,以毛细血管为主,并见肉芽成份,对照组新生血管相对较少,两组间新生小血管管腔大小则无明显差异;免疫组化检测显示仅实验组皮瓣中有VEGF表达。结论：腺病毒-VEGF基因重组体能通过促进预构皮瓣的血管新生,增加预构皮瓣的存活率。     

血管内皮生长因子促进跨区供血反流轴型皮瓣成活的实验研究

目的研究血管内皮生长因子（vascular endothelial growth factor，VEGF）的局部皮下注射对大鼠背部跨区供血反流轴型皮瓣成活的影响及效果。方法取20只SD大鼠，制备8cm×2cm大鼠背部跨区供血反流轴型皮瓣模型，随机分成两组，每组10只。实验组：于皮瓣远端7．5cm及6．5cm处共选择4个对称位点，分别予100ng／100μlVEGF溶液50μl；对照组：每一位点予生理盐水50μl。术后1～7d行皮瓣大体观察，并于7d处死大鼠，切取皮瓣，行皮瓣成活率测定、组织学观察及血管密度检测。结果大体观察，实验组皮瓣成活面积明显大于对照组，实验组皮瓣成活面积15．55±0．27cm^2，对照组13．42±0．57cm^2，差异有统计学意义（P〈0.01）。组织学观察，实验组皮瓣血管密度34．40±3．75个／10倍光镜下视野，对照组21．00±3．16个／10倍光镜下视野，差异有统计学意义（P〈0.01）。镜下见实验组有大量新生肉芽组织形成，胶原纤维排列规则，成纤维细胞较多，炎性细胞浸润程度轻；对照组新生肉芽组织少，胶原纤维凝集成块，成纤维细胞少，炎性细胞浸润程度重。结论VEGF在皮瓣成活早期，通过促进缺血皮瓣新生血管形成，增加血管数量，改善缺血组织的血液供应，促进皮瓣成活；在皮瓣形成时局部、单次、足量应用VEGF是促进跨区供血反流轴型皮瓣远端成活的有效方法。     

扩张血管束移植预构皮瓣的实验研究

为研究扩张血管束移植预构皮瓣存活范围，将股动静脉血管束移植入８只雄性兔的腹部皮下肉膜内，一侧皮下同时置入皮肤扩张器，对侧置入硅胶薄膜，术后２周开始扩张，术后４周进行预构皮瓣活体血管染色和移植存活范围的比较研究，结果：扩张的预构皮瓣血管染色范围和移植后存活范围均大于未扩张的预构皮瓣。认为，扩张的机械性刺激及促进血管束的血管进一步改建可能是增加扩张预构皮瓣范围的原因。     

碱性成纤维细胞生长因子对大鼠皮瓣愈合的实验研究

目的 观察碱性成纤维细胞生长因子(bFGF)对大鼠皮瓣损伤后创面愈合及血管生成的作用.方法 Wistar大鼠24只,制作大鼠皮瓣模型.实验组创面使用bFGF在皮瓣距离蒂部2、5、8 cm处分别注射bFGF 100 U(约0.025 ml)于皮瓣基底部,于第1、5、10天各重复1次,共3次,对照组创面给予等量生理盐水作为对照,观察其创面愈合时间及血管的变化,并分别取相同部位皮瓣组织块行病理组织学检查及免疫组化分析.结果 实验组大鼠皮瓣创面愈合时间比对照组缩短(3.0±0.56)d,创面新生血管内皮生长因子阳性表达增多,新鲜肉芽组织形成增多.结论 碱性成纤维细胞生长因子有促进大鼠皮瓣损伤后血管内皮生长因子的表达,刺激内皮细胞分裂,促进新生血管及肉芽组织形成,从而加速皮瓣损伤后愈合.     

皮瓣延迟后对皮瓣预制时间影响的实验研究

为了探寻缩短皮瓣预制时间的新方法，作者设计了两组皮瓣预制方法进行比较。Ａ组为皮瓣延迟实验组，Ｂ组为正常皮瓣预制对照组。皮瓣预制后２周进行血管灌注检查和皮瓣移植。结果：Ａ组皮瓣成活范围大，植入血管与原皮瓣之间血管吻合支多；Ｂ组皮瓣成活面积小，血管网形成范围小，吻合支少。结论：皮瓣延迟后皮瓣预制时间可大大缩短，从而缩短了手术周期。     

兔股动脉和静脉预构轴型扩张皮瓣的实验观察

目的 通过兔股动脉、静脉预构轴型扩张皮瓣的微循环血流晕动态变化、光镜下结构的改变及其成活面积,为预构轴型扩张皮瓣的临床应用提供依据.方法 选择新西兰白兔40只,随机分为4组:预构轴型扩张皮瓣组、预构轴型不扩张皮瓣组、单纯预构轴型皮瓣组及无蒂游离皮瓣组,每组4只,前2组股动脉、静脉移位后,预构轴型扩张皮瓣组、预构轴型不扩张皮瓣组分别在肉膜深面置入容量为50 ml长方形皮肤软组织扩张器,预构轴型扩张皮瓣组7 d后开始注水;无蒂游离皮瓣组为对照组,未采取预构及扩张处理.定期对4组皮肤进行微循环血流量检测,并取样进行光镜观察.预构术后52 d,前3组形成以预构股动静脉血管束为蒂的岛状皮瓣,游离皮瓣组则形成无蒂游离皮瓣后均原位缝合,观察其成活面积.结果 预构轴型扩张皮瓣组较其他组微循环血流量增加,成活面积大[(97.54±2.73)%],光镜下改变显著(P<0.05).结论 扩张术能促进预构轴型皮瓣的血管化进程,明显增大预构轴型皮瓣成活面积,增加其移植的安全性.     

血管束移植预构轴型皮瓣的血供范围

为了研究不同因素对血管束移植预构轴型皮瓣范围的影响，将血管束移植入３８只雄性兔的腹部皮下，对术后不同时间、植入不同管径血管束、植入皮下不同层次以及同时埋入皮肤扩张器的预构轴型皮瓣，进行了皮瓣活体血管染色和移植存活范围的比较研究。结果提示：行预构轴型皮瓣移转的合适时机在术后的３～４周；大管径较小管径血管束及血管束植入受区较丰富的血管网层次其预构皮瓣的面积大；所预构的皮瓣范围，包括以血管束为轴的受区邻近区域和发自该区域走向皮瓣中远部的小动脉所支配的区域，呈不规整形态；植入血管束同时皮下埋入扩张器，于术后２周开始扩张，术后４周移转是可行的     

血管内皮生长因子促进预构皮瓣成活的实验研究

目的　研究使用重组人类血管内皮生长因子 (Vascularendothelialgrowthfactor,VEGF)对预构皮瓣存活的作用 ,探讨VEGF能否促进正常血供组织的血管化。方法　取大鼠自体尾动脉 8cm移植 ,两端分别与股动、静脉吻合 ,成环状植入下腹部皮下组织 ,对照组局部应用 0 9%NaCl和16 %聚乙烯乙醇 ,实验组将VEGF分别溶于 0 9%NaCl和 16 %聚乙烯乙醇局部应用。分别于术后 3,4 ,5周以植入的尾动脉为血管蒂于下腹部形成 3cm× 4cm大小皮瓣 ,游离掀起皮瓣后缝回原处 ,7d后运用面积仪测出存活皮瓣面积的百分比。结果　第 5周后的皮瓣存活率VEGF组 (75 0 0 % ,5 8 4 1% )明显优于实验组 (10 % ,2 5 % )。结论　VEGF有利于预构皮瓣的存活。     

血管内皮祖细胞和血管内皮生长因子促进预构皮瓣血管新生作用的比较

目的 比较血管内皮祖细胞(endothelial progenitor cells,EPCs)与血管内皮生长因子(vascular endothelial growth factor,VEGF)在促进预构皮瓣血管新生作用上的差异,探讨EPCs移植提高预构皮瓣存活面积的可行性.方法 分离雄性Wistar大鼠(45只)一侧股血管柬,转位植入腹部皮下,建立预构皮瓣实验模型.将体外诱导分化的EPCs(组Ⅰ,n=15)和VEGF(组Ⅱ,n=15)分别注射于皮瓣局部,对照组仅注射PBS溶液(组Ⅲ,n=15).4周后形成以植入血管为蒂的岛状皮瓣,原位缝合;术后7 d对皮瓣存活率、血管密度计数进行检测.结果 组Ⅰ、组Ⅱ、组Ⅲ的皮瓣存活率分别为(87.26±10.13)%、(66.13±9.9)%、(55.59±13.06)%,组Ⅰ分别与组Ⅱ和组Ⅲ比较,差异均有统计学意义(P<0.001);微血管密度分别为:(38.67±9.52)个/mm~2、(25.83±6.33)个/mm~2、(26.5±5.61)个/mm~2(P<0.05).结论 EPCs促进预构皮瓣血管新生的作用优于VEGF,局部应用骨髓来源的EPCs可以有效地提高预构皮瓣存活面积.     

VEGF促进预构皮瓣血管新生的实验研究

目的探讨VEGF重组蛋白促进大鼠预构皮瓣血管新生、提高皮瓣存活面积的可行性。方法建立大鼠腹部预构皮瓣模型;30只Wistar大鼠随机分为两组;局部应用VEGF165（组Ⅰ）、PBS（组Ⅱ）;4周后形成以植入血管为蒂的岛状皮瓣,原位缝合;术后7d对皮瓣存活、血管新生情况进行检测。结果组Ⅰ、组Ⅱ的皮瓣存活率分别为66．13％±9．9％,55．59％±13．06％（P〈0．05）;组Ⅰ与组Ⅱ比较,微血管显影血管网更丰富,范围更广,分支更粗,内含墨汁的血管在皮瓣的表皮真皮、皮下层均有分布;微血管计数组Ⅰ、组Ⅱ分别为25．83±6．33条／mm^2,26．5±5．61条／mm^2（p〉0．05）。结论VEGF可以促进预构皮瓣的血管新生,提高存活率。     

血管内皮细胞生长因子和碱性成纤维细胞生长因子加速预构扩张皮瓣成熟的研究

目的　观察以生物蛋白胶局部缓释血管内皮细胞生长因子 (VEGF)和碱性成纤维细胞生长因子(b FGF)应用于兔预构扩张皮瓣对细胞增殖及凋亡、血管化进程 ,以及皮瓣成熟的作用。　方法　将新西兰大耳白兔 5 3只随机分为正常、空白、生物蛋白胶、VEGF直接应用、VEGF胶及 b FGF胶共 6组 ,兔耳中央动静脉束植入预构扩张皮瓣 ,14天后形成 3cm× 5 cm岛状瓣。分别进行皮瓣成活面积、激光多普勒血流量、铅丹灌注、墨汁灌注、PCNA免疫组化和 TUNEL 凋亡检测。　结果　两种生长因子应用组皮瓣成活面积较其它组增加 ,血流灌注量增多 ,新生毛细血管密度加大 ,细胞增殖提高、凋亡减少。　结论　 VEGF和 b FGF均能通过刺激细胞增殖和减少凋亡发生来促进血管新生和预构扩张皮瓣成熟 ,用生物蛋白胶缓释生长因子有独特效果。     

Preserving osseous viability in osteocutaneous flap prefabrication: experimental study in rabbits

This study presents a technique that preserves osseous viability in prefabricated osteocutaneous flaps with a soft-tissue vascular carrier, with a pedicled skin flap acting as the vascular carrier to neovascularize a partially devascularized bone segment before its transfer. Using a total of 50 New Zealand White rabbits, two groups were randomized as experimental and control animals. In the experimental group (n = 30), a bipedicled dorsal scapular skin flap was anchored with sutures to the scapular bone, by bringing it into contact with the exposed dorsal surface of the bone after stripping the dorsal muscular attachments. Following 4 weeks of neovascularization, the prefabricated composite flaps were harvested, based on the caudally-based dorsal skin flap, after stripping the ventral muscular attachments of the bone. In the control group (n = 20), non-vascularized scapular bone grafts were implanted under bipedicled dorsal scapular skin flaps with sutures. After 4 weeks, prefabricated composite flaps were harvested, based on the caudally-based dorsal skin flap. In both groups, on day 7 after the second stage, the viability of the bony component of the flaps was evaluated by direct observation, scintigraphy, measurement of bone metabolic activity, microangiography, dye injection study, and histology. Results indicated that the bone segments in the experimental group demonstrated a greater survival than in the control group. The authors conclude that this technique of osteocutaneous flap prefabrication preserves the viability of the bony component with a soft-tissue vascular carrier, in contrast to the conventional method of pre-transfer grafting. The technique may be useful clinically in selected cases.     

水蛭素对大鼠随意型皮瓣存活的影响

目的 研究水蛭素对大鼠背部超长随意型皮瓣存活的影响.方法 采用改良大鼠"McFarlane flap"模型,将实验动物随机分为水蛭素实验组(水蛭素组)和生理盐水对照组(生理盐水组),水蛭素组局部注射3 ml(30 ATU)水蛭素,生理盐水组则注射3 ml生理盐水,连续注射7 d后分别检测两组皮瓣的存活面积百分比,并取皮瓣近、中、远段(即Ⅰ、Ⅱ、Ⅲ区)组织做光镜观察,免疫组化法检测血管内皮生长因子(VEGF)和碱性成纤维细胞因子(bFGF)的表达.结果 术后7 d,水蛭素组皮瓣的存活面积百分比为(69.52±3.23)%,生理盐水组为(50.36±2.37)%,水蛭素组显著高于生理盐水组,差异有统计学意义(P＜0.01);水蛭素组皮瓣坏死与存活并存的Ⅱ区,组织水肿、炎性细胞浸润情况明显比生理盐水组轻.水蛭素和生理盐水组皮瓣Ⅱ区的新生血管计数分别为(28.24±4.23)个/mm2和(17.45±5.43)个/mm2,两组比较差异有统计学意义(P＜0.05).通过计算累积吸光度A值(IA),得到水蛭素和生理盐水组VEGF阳性量分别为9262.23±896.99和4938.05±1623.67,bFGF阳性量分别为5122.83±1176.12和2779.45±472.00,水蛭组VEGF及bFGF的表达均高于生理盐水组,差异均有统计学意义(P＜0.01).结论 水蛭素可能通过体内一系列复杂的调控通路,最终增加VEGF、bFGF表达,促进皮瓣新生血管增生,改善皮瓣血供,减轻炎性反应,降低缺血皮瓣的坏死率,从而提高大鼠随意型皮瓣的存活.

Abstract：

Objective To investigate the effect of Hirudin on random skin flap survival in rats.Methods 24 SD rats were randomly divided into control group and experimental group. The "McFarlane flap(3 cm ×9 cm)" rat models were established on the rat dorsum. 3 ml Hirudin (30 ATU) was injected into the flap in the experimental group, while 3 ml saline in the control group. The injection was performed for 7 days. The flap survival area in the two groups was measured. The tissue samples were taken from proximal( Ⅰ ), middle( Ⅱ ) and distal( Ⅲ ) portions of flaps for histologic study. The VEGF and bFGF expression was also detected with immunohistochemistry method. Results 7 days after operation, the flap survival rate was ( 69.52 + 3.23 )% in the experimental group, while ( 50.36 ± 2.37 )% in control group,showing a significant difference between the two groups ( P ＜ 0.01 ). In the middle portion, tissue edema and infiltration of neutrophils in experimental group was markedly slighter than that in control group. The VEGF and bFGF expression and neovascularization was enhanced markedly in experimental group.Conclusions Hirudin can increase the survival of random pattern skin flaps. It may increase the VEGF,bFGF expression through a series of complex regulatory pathway. Then flap neovascularization is promoted and the flap blood supply is increased.     

Gene therapy with adenovirus-mediated VEGF enhances skin flap prefabrication

We investigated the feasibility in rats of enhancing skin-flap prefabrication with subdermal injections of adenovirus-encoding vascular endothelial growth factor (Ad-VEGF). The left saphenous vascular pedicle was used as a source for vascular induction. A peninsular abdominal flap (8 x 8 cm) was elevated as distally based, keeping the epigastric vessels intact on both sides. After the vascular pedicle was tacked underneath the abdominal flap, 34 rats were randomly divided into three groups according to treatment protocol. The implantation site around the pedicle was injected with Ad-VEGF in group I (n = 10), with adenovirus-encoding green fluorescent protein (Ad-GFP) in control group I (n = 14), and with saline in control group II (n = 10). All injections were given subdermally at four points around the implanted vessel by an individual blinded to the treatment protocol. The peninsular flap was sutured in its place, and 4 weeks later, an abdominal island flap based solely on the implanted vessels was elevated. The prefabricated island flap was sutured back, and flap viability was evaluated on day 7. Skin specimens were stained with hematoxylin and eosin for histological evaluation. In two rats from each group, microangiography was performed to visualize the vascularity of the prefabricated flaps. There was a significant increase in survival of prefabricated flaps in the Ad-VEGF group compared to the control groups: Ad-VEGF, 88.9 +/- 6.1% vs. Ad-GFP, 65.6 +/- 9.4% (P < 0.05) and saline, 56.0 +/- 3.4% (P < 0.05). Sections from four prefabricated flaps treated with Ad-GFP revealed multiple sites of shiny deposits of green fluorescent protein around the area of local administration 1 day and 3 weeks after gene therapy. Histological examination done under high-power magnification (x400) with a light microscope revealed increased vascularity and mild inflammation surrounding the implanted vessel in all groups. However, we were unable to demonstrate any significant quantitative difference with respect to vascularity and inflammatory infiltrates in prefabricated flaps treated with Ad-VEGF compared with controls. Microangiographic studies showed increased vascularity around the implanted pedicle, which was similar in all groups. However, vascularization was distributed in a larger area in the prefabricated flaps treated with Ad-VEGF. In this study, the authors demonstrated that adenovirus-mediated VEGF gene therapy increased the survival of prefabricated flaps, suggesting that it may allow prefabrication of larger flaps and have the potential to reduce the time required for flap maturation.     

Porcine small intestinal submucosa as a carrier for skin flap prefabrication

The feasibility of porcine small intestinal submucosa (SIS) as a carrier in skin flap prefabrication was examined in this study. Thirty-eight rats were randomly divided into five groups. The saphenous vascular bundle was used as the vascular carrier. In group 1 (n = 8), an arteriovenous fistula was made by anastomosis of distal saphenous artery and vein. A SIS patch (1.5 x 2 cm2) was placed underneath the vascular bundle. In group 2 (n = 8), the vascular bundle was isolated and laid over the SIS patch. The distal saphenous vessels were ligated when the flap was raised. In group 3 (n = 8), an arteriovenous fistula was made without SIS implant. In group 4 (n = 8), the flap was raised with only the vascular bundle with the distal end ligated. After 2 weeks of maturation, the flap was raised with only the vascular bundle. In group 5 (n = 6), SIS was implanted and the flap including the SIS patch was raised and replaced without the vascular pedicles. The survival of the flaps and histology were evaluated at 5 days after flap replacement. The results showed that the average survival area in group 1 was 99% +/- 3% and the survival area in group 2 was 86% +/- 16%. The mean survival areas in group 3 and 4 were 60% +/- 9% and 25% +/- 10%, respectively. No flap survival was observed in the group 5. These were significantly lower than in groups 1 and 2 (p < 0.05, p < 0.01). Histology showed that SIS patch was incorporated into the adjacent connective tissue and increased amounts of neovascularization were seen between the collagenous sheets and dermis. In conclusion, this study demonstrated that porcine SIS can incorporate into the adjacent tissue and induce angiogenesis in flap prefabrication. This biomaterial can provide a scaffold for supporting and enhancing the survival of vascular prefabricated skin flap.     

Neovascularization and free microsurgical transfer of in vitro cartilage-engineered constructs

Cartilage tissue engineering shows to have tremendous potential for the reconstruction of three-dimensional cartilage defects. To ensure survival, shape, and function, in vitro cartilage-engineered constructs must be revascularized. This article presents an effective method for neovascularization and free microsurgical transfer of these in vitro constructs. Twelve female Chinchilla Bastard rabbits were used. Cartilage-engineered constructs were created by isolating chondrocytes from auricular biopsies, amplifying in monolayer culture, and then seeding them onto polycaprolactone scaffolds. In each prefabricated skin flap, three in vitro cartilage-engineered constructs (2 x 2 x 0.5 cm) and one construct without cells (served as the control) were implanted beneath an 8 x 15 cm random-pattern skin flap, neovascularized by implantation of an arteriovenous vascular pedicle with maximal blood flow. Six weeks later, the neovascularized flaps with embedded cartilage-engineered constructs were completely removed based on the newly implanted vascular pedicle, and then freely retransferred into position using microsurgery. Macroscopic observation, selective microangiography, histology, and immunohistochemistry were performed to determine the construct vitality, neovascularization, and new cartilage formation. The results showed that all neovascularized skin flaps with embedded constructs were successfully free-transferred as free flaps. The implanted constructs were well integrated and protected within the flap. All constructs were well neovascularized and showed histologically stability in both size and form. Immunohistology showed the existence of cartilage-like tissue with extracellular matrix neosynthesis.     

Use of fascial grafts as an interface in flap prefabrication: an experimental study.

An experimental study was conducted to investigate whether a fascial graft can be used as an interface between a vascular pedicle and target tissue to augment tissue survival in a prefabricated flap. Thirty-six male Sprague-Dawley rats were divided into three experimental groups according to the type of the recipient bed prepared for the vascular implantation. The left saphenous vascular pedicle was used as the vascular source. A 9 x 9-cm inferiorly based peninsular abdominal flap was elevated in each animal. In group I, the pedicle was tacked beneath the abdominal flap, in which the epigastric fascial layer was untouched. In group II, a 3 x 5-cm graft of epigastric fascia was harvested from the abdominal flaps under loupe magnification. The graft was sutured back into its original position after a 180-deg rotation. The vascular pedicle was then implanted just beneath the center of the fascial graft. In group III, the same size of epigastric fascia was removed in the same manner as group II, exposing the subcutaneous layer for pedicle implantation. Four weeks later, abdominal flaps were raised as island flaps connected only to the saphenous pedicle and were sutured in place. Flap viability was assessed visually on day 7. Overall, the ultimate flap survival in group I was the largest, with some necrotic areas at the periphery of the flaps. In group II, flap survival was typically centralized over the fascial graft, and crescent-shaped necrosis was noted superiorly. In group III, an almost linear pattern of survival overlying the vascular pedicle was observed. The mean surviving flap area of group I (12.13 +/- 1.615 cm2) was statistically greater than that of group II (8.83 +/- 0.663 cm2, p < 0.001) and group III (6.3 +/- 0.815 cm2; p < 0.001). There was a statistically significant difference between the mean flap survival in groups II and III (p < 0.001). Vascular arborization was examined by microangiography, and specimens were processed for histological staining. In group II, vascularization was distributed in a larger area along the fascial graft in comparison with limited vascularization around the pedicle in group III. In this study it was revealed that the interposition of a fascial graft as an interface between the vascular source and the target tissue seems to increase the size of the prefabricated flap.     

Neovascularization in prefabricated flaps using a tissue expander and an implanted arteriovenous pedicle

Creating prefabricated flaps using tissue expanders in combination with the implantation of maximal blood flow vascular pedicles into suitable tissue areas represents a new tendency in the reconstruction of large skin defects. In 42 Chinchilla Bastard female rabbits weighing 3,700-4,600 g, skeletonized arteriovenous pedicles with maximal blood flow, dissected from the femoral and saphena magna bundles, were implanted underneath abdominal fasciocutaneous flaps. Oval tissue expanders of 250 ml were placed and fixed on the abdominal wall to expand these prefabricated flaps. The evaluation parameters were macroscopic observation, blood analysis, selective microangiography, histology, and scintigraphy. The study results showed that neovascularization in expanded prefabricated flaps was established from newly formed vessels generated from the implanted pedicles and their vascular connections with the originally available vasculature in the flap. After 20 days of prefabrication, the entirety of the expanded prefabricated flaps was perfused by blood flow supplied from newly implanted arteriovenous pedicles. The study indicated that an expanded prefabricated flap can be successfully created by the simultaneous implantation of a maximal blood flow pedicle in combination with flap expansion.