动脉化静脉皮瓣移植的实验研究及临床应用

为了探讨动脉化静脉皮瓣成活机理及静脉回流对皮瓣成活的影响，选用健康家兔３４只，随机分为实验组和三个对照组：①实验组，切断中央动脉、静脉及神经，将中央动脉近心端与中央静脉远心端吻合，保留前、后边缘静脉；②对照１组，保留中央静脉及前、后边缘静脉，结扎并切断中央动脉；③对照２组，结扎后边缘静脉，其余同实验组；④对照组３组，切断中央动脉、静脉，重新吻合中央动脉，保留前、后边缘静脉。以兔耳动脉化静脉皮瓣为模     

静脉瘀血对静脉动脉化皮瓣微循环的影响

目的研究静脉瘀血对静脉动脉化皮瓣微循环的影响。方法３０只新西兰大白兔随机分为Ａ、Ｂ、Ｃ３组，Ａ组为动脉皮瓣，Ｂ组为静脉动脉化皮瓣，Ｃ组为静脉瘀血的静脉动脉化皮瓣，每组各１０只。术后３０分钟，１，２，３，４，５小时分别应用显微电视系统通过耳窗对各组皮瓣微循环进行动态观察，７天后记录皮瓣成活情况。结果静脉瘀血的静脉动脉化皮瓣微循环血流缓慢，微血栓逐渐增多，皮瓣成活率低。结论静脉瘀血可破坏静脉动脉化皮瓣静脉系统的代偿机制，影响皮瓣血液灌流，从而导致皮瓣成活率下降     

静脉瘀血对静脉动脉化皮瓣微循环的影响

目的 研究静脉瘀血对静脉动脉化皮瓣微循环的影响。方法 ３０只新西兰大白兔随机分为Ａ、Ｂ、Ｃ３组，Ａ组为动脉皮瓣，Ｂ组为静脉动脉化皮瓣，Ｃ组为静脉阏血的静脉化皮瓣，每组各１０只。术后３０分钟，１，２，３，４，５小时分别应用显微电视系统通过耳窗对各组皮瓣微循环进行动态观察，７天后记录皮瓣成活情况。结果 静脉瘀血的静脉动脉化皮瓣微循环血流缓慢，微血栓逐渐增多，皮瓣成活率低。结论 静脉瘀血可破坏静脉动脉化     

脂蛋白脂酶,肝脂酶及载脂蛋白在兔胆囊结石中的变化及作用

目的研究脂蛋白脂酶,肝脂酶及载脂蛋白在兔胆囊结石中的变化及作用。方法采用日本杂交大耳兔５０只,随机分为对照组,１周组、２周组、３周组和４周组为实验组,实验组饲以１．２％高胆固醇膳食诱以胆囊结石,测定各组脂蛋白脂酶、肝脂酶、血清载脂蛋白和脂质的动态变化,脂蛋白脂酶和肝脂酶采用比色法测定,血清载脂蛋白采用圆周免疫扩散法测定,血清脂质采用酶法测定。结果随着高胆固醇膳食进食时间延长,２周组、３周组和４周组分别有４／１０,６／１０和７／１０只动物出现胆囊结石;肝素化血清中脂蛋白脂酶和肝脂酶活性增加,以３周组和４周组升高明显（与对照组比较,Ｐ＜０．０５）;血清载脂蛋白ａｐｏＢ１００,ａｐｏＣⅡ,ａｐｏＣⅢ明显增加（与对照组比较,Ｐ＜０．０５）,ａｐｏＡＩ在４周组时降低（与对照组比较,Ｐ＜０．０５）;血清总胆固醇,甘油三酯,磷脂,低密度脂蛋白胆固醇和极低密度脂蛋白胆固醇逐渐明显升高（与对照组比较Ｐ＜０．０５）,高密度脂蛋白胆固醇及其亚组份有降低趋势,但与对照组比较差异无显著性（Ｐ＜０．０５）。结论高胆固醇膳食后,脂蛋白脂酶和肝脂酶活性增强,血清载脂蛋白和酯质代谢异常变化,促进了胆囊结石形成。     

指背旗形皮瓣的实验研究与临床应用

为探讨指背旗形皮瓣的成活机理，应用恒河猴１只，做了８个指背旗形皮瓣的实验，其中近端蒂６个，远端蒂２个，术后作系统的肉眼摄像，激光多普勒血流测定和组织人段叶片观察，结果显示：（１）当皮瓣的长：宽为１０：１时，仍能成活，且无发紫，水肿出现。（２）术后前２天皮瓣的激光多普勒测定值较术前水平稍有下降，但不明显（Ｐ〉０．０５）。术后第３天开始，血流测定值逐渐上升，于第５天达到或超过术前水平；（３）皮瓣成活后     

氯胺酮对离体小鼠心肌细胞的毒性作用

目的：探讨氯胺酮对心肌细胞的毒性作用。方法：将经原代培养成活４天后的大鼠心肌细胞分为四组，Ａ组为对照组，Ｂ、Ｃ、Ｄ三组分别加入氯胺酮１×１０＾－５、１×１０＾－４及１×１０＾－３ｍｏｌ／Ｌ。实验开始后２、４、８及２４小时评定心肌细胞搏动功能、细胞酶及培养液中电解质改变，并形态学变化。结果：Ｂ组各时点搏动频率均明显加快（Ｐ〈０．０５和Ｐ〈０．０１），Ｃ及Ｄ组搏动频率减慢（Ｐ〈０．０５和Ｐ〈０．０１）     

指背旗形皮瓣的实验研究与临床应用

为探讨指背旗形皮瓣的成活机理，应用恒河猴１只，做了８个指背旗形皮瓣的实验，其中近端蒂６个，远端蒂２个。术后作系统的肉眼摄像、激光多普勒血流测定和组织分段切片观察。结果显示：①当皮瓣的长∶宽为１０∶１时，仍能成活，且无发紫、水肿出现。②术后前２天皮瓣的激光多普勒测定值较术前水平稍有下降，但不明显（Ｐ＞０．０５），术后第３天开始，血流测定值逐渐上升，于第５天达到或超过术前水平。③皮瓣成活后组织分段切片表明，指背旗形皮瓣的蒂部无知名的动脉血管，但含有丰富的指背静脉。由此认为指背旗形皮瓣实为一种静脉皮瓣，其保留的静脉周围组织中的微动脉血管能给皮瓣以血供，而指背静脉提供丰富的静脉回流通道。在此基础上，临床应用２０个指背旗形皮瓣修复了手指皮肤缺损合并骨、肌腱外露者１２例，获得满意效果。     

感觉训练对邻指皮瓣移位后感觉恢复影响的观察

为探讨感觉训练对带蒂失神经皮瓣感觉恢复的影响。我们观察了自１９８６年至１９９１年５年间．施行邻指皮瓣转位修复指端缺损的４５例病人，随机分对照组和训练组。随访１年，结果：两组在术后３个月时感觉功能评价无显著性差异Ｐ＞０．０５；在４．５个月的Ｓ＿２．６个月的Ｓ＿２＋和Ｓ＿３、１年的Ｓ＿３＋和Ｓ＿４之间均有高度显著差异Ｐ＜０．０１，且提示训练组的恢复在速度上较对照组快，程度上较对照组完全。训练组１年后８８．２％病例达到Ｓ＿３＋以上，而对照组仅６．７％病例达到Ｓ＿３＋。文中介绍了训练的具体方法，起始时间和注意事项。     

超声多普勒对阻隔式皮瓣血供机制的实验研究

为探索阻隔式皮瓣的血供机制并确定其转位的时机和标准，选用版纳微型猪５只，采用左、右侧自身对照，经阻隔迟延术第３，７，１０及２０天，转位术后第３，７，１０天进行大体观察、超声多普勒、皮瓣表面皮肤温度测定及组织学检查。结果发现，实验组转位后皮瓣均成活；对照组皮瓣转位后有３０％～５０％坏死。阻隔迟延术后第７天开始用超声多普勒仪对实验组及对照组皮瓣进行监测，发现阻隔式皮瓣经阻隔迟延术后第７天就可在蒂部听到动脉血流回声，并随着时间推移由皮瓣蒂部向远端扩展，达整个皮瓣长度的１／２时，即可行皮瓣转位；对照组无动脉血流回声。对照组皮瓣和实验组皮瓣术前皮温测定，两组间无差异（Ｐ＞０．０５），而阻隔迟延术及转位术后两组皮瓣皮温测定值均有非常显著差异（Ｐ＜０．０１）。证明，超声多谱勒探查的指标可作为阻隔式皮瓣血供和皮瓣转移时机一个科学、客观的方法和标准，且重复性好，无创的优点。     

自由基与轴型真皮下血管网皮瓣成活的实验研究

目的：研究自由基在轴型真皮下血管网皮瓣成活机制的作用。方法：在１０只白家猪侧腹部和臀部制备真皮下血管网皮瓣（实验组）和轴型筋膜皮瓣（对照组）各３０块。皮瓣大小５ｃｍ×１５ｃｍ，术后７天测定二组皮瓣的成活长度，并对距蒂部５ｃｍ、１０ｃｍ和１５ｃｍ处的实验组全层、对照组皮肤层和脂肪层３种组织的自由基含量进行了检测。结果：实验组成活长度为１０．８±１．２４ｃｍ，对照组为８．５±１．６２ｃｍ（Ｐ＜０．０１）；实验组５ｃｍ、１０ｃｍ和对照组皮肤层５ｃｍ处自由基含量较低，对照组脂肪层１０ｃｍ和１５ｃｍ处含量最高。结论：对照组中远端皮下脂肪组织在皮瓣的成活过程中产生的自由基较多而不利于其成活，成活长度较实验组减少了２１．３％；而实验组因去除了中远端大部分脂肪组织，自由基含量明显减少，成活长度增加。     

Pre-arterialisation of the arterialised venous flap: an experimental study in the rat.

Arteriovenous fistulae cause haemodynamic and morphological changes to the local venous channels. We have used the concept of preformed arteriovenous fistulae to study the viability improvement of arterialised venous flaps. Five groups of flaps were created using the abdominal skin of the Wistar rat (n= 10 in each group) with a silastic sheet implanted underneath. Group 1 (control) contained a flap without a vascular supply, group 2 (venous perfusion flap) contained a single pedicled skeletonised vein and a draining vein, and group 3 (arterialised venous flap) contained an arteriovenous shunt proximal to the single pedicled skeletonised vein and a draining vein; in group 4 (7 day pre-arterialised flap) the arteriovenous shunt was performed 7 days before the flap was raised in the same procedure as group 3, and in group 5 (14 day pre-arterialised flap) the arteriovenous shunt was performed 14 days before the flap was raised. The surviving surface areas of the flaps in each group, assessed 7 days after raising, were 0%, 22.21%, 54.32%, 62.21% and 97.47%, respectively. There was a statistically significant difference in survival between venous perfusion flaps and arterialised venous flaps (P= 0.05). Only the 14 day pre-arterialised flaps had a statistically significantly larger area of survival than arterialised venous flaps (P= 0.05). Microangioarchitecture of the pre-arterialised group, studied by the microvascular corrosion-cast technique combined with scanning electron microscopy and transmission electron microscopy, revealed dilatation of veins, numerous small neo-vessels and a decrease in or total absence of functioning valves. We conclude that 14-day pre-arterialisation in the rat model improved the survival of arterialised venous flaps by increasing collateral pathways for arterialised blood flow through the flap.     

局部应用重组水蛭素对家兔耳静脉淤血皮瓣成活的影响

目的 观察局部应用重组水蛭素对家兔耳静脉淤血皮瓣成活的影响.方法 选取健康普通大耳白兔18只,按照随机数字表法分为对照组、低分子肝素治疗组、重组水蛭素治疗组,每组6只.各组家兔麻醉后在左耳背制作静脉淤血皮瓣模型:皮瓣大小为6 cm×3 cm,以耳中心动脉为惟一血供、1 cm宽蒂部为惟一静脉回流途径.术后分别于皮瓣下多点均匀注射 1 mL生理盐水、低分子肝素(625 U)、重组水蛭素(1 U),皮瓣原位缝合.观察皮瓣外观并计算成活率;术后1、3、5、7 d 取皮瓣远端组织检测血栓素B2含量.对数据行单因素方差分析、t检验.结果 各组家兔皮瓣完全坏死区域毛发脱落明显;术后皮瓣均肿胀明显,远端淤血形成,对照组颜色明显深于2个治疗组.术后1 d 重组水蛭素治疗组1只家兔、低分子肝素治疗组2只家兔、对照组4只家兔出现明显血肿.低分子肝素治疗组、重组水蛭素治疗组家兔皮瓣成活率分别为(92.3±1.7)%、(94.8±1.9)%,均高于对照组[(77.9±1.2)%,F=191.29,P＜0.05].2个治疗组家兔皮瓣成活率接近(t=2.75,P>0.05).术后3、5 d,2个治疗组家兔血栓素B2含量均明显低于对照组(t值为6.68~30.55,P值均小于0.01),而2个治疗组家兔血栓素B2含量接近(t值分别为1.22、6.44,P值均大于0.05).结论 局部应用低分子肝素或重组水蛭素,可明显改善家兔皮瓣的静脉淤血,提高皮瓣成活率.

Abstract：

Objective To observe the effect of local injection of recombinant hirudin on survival of skin flaps with venous congestion in a rabbit model. Methods Eighteen healthy rabbits were enrolled and divided into heparin-treatment (HT),recombinant hirudin treatment (RHT) and control (C) groups according to the random number table,with 6 rabbits in each group. After intravenous anesthesia with 20 g/L pentobarbital sodium,model of skin flaps with venous congestion in the size of 6 cm×3 cm was reproduced in the dorsal side of left ear of each rabbit,in which central artery of ear served as the only blood supply,and a pedicle of 1 cm in width including central vessel of ear and its accompanying nerves as the only venous return pathway. Each flap in RHT,HT,C groups was respectively given 1 mL recombinant hirudin (1 U),low-molecular-weight heparin (625 U),and isotonic saline via multi-point and homogenous injection,then they were sutured in site. Appearance and survival rate of the flaps were observed after operation. Specimens of the distal part of flaps were harvested for determination of thromboxane B2 (TXB2) on post operation day (POD) 1,3,5,7. Data were processed with one-way analysis of variance and t test. Results Rabbit model of skin flaps with venous congestion was reproduced successfully. Obvious hair loss was observed in completely necrotic parts of flap in each group. Obvious edema was observed in all flaps with venous congestion at distal site. The color of flaps in HT and RHT groups were lighter as compared with that in C group,and apparent hematoma of flap was observed in 1 rabbit of RHT group,2 rabbits of HT group,4 rabbits of C group on POD 1. The survival rate of flap in HT and RHT groups was respectively (92.3±1.7)% and (94.8±1.9)%,both higher than that in C group[(77.9±1.2)%,F=191.29,P＜0.05]. There was no statistical difference in survival rate of flap between HT group and RHT group (t=2.75,P>0.05). The content of TXB2 in HT and RHT groups on POD 3,5 was respectively lower than that in C group (with t value from 6.68 to 30.55,P values all below 0.01),but there was no statistical difference between HT and RHT groups (with t value respectively 1.22,6.44,P values all above 0.05). Conclusions Local injection of low-molecular-weight heparin or recombinant hirudin can significantly ameliorate venous congestion of skin flap in rabbit ear,and improve its survival rate.     

Effects of methylprednisolone on the viability of experimental flow-through venous flaps

In this study, the effects of a corticosteroid, methylprednisolone, on the survival of flow-through venous flaps were investigated in rabbits. Flow-through venous flaps, sized 3.0 x 4.5 cm, were raised in the rabbit-ear model. Animals were randomly distributed into three groups, and 30 flaps were raised as follows: Group 1 (n=10): control flow-through venous flaps (intramuscular saline injection 2 ml/d); Group 2 (n=10): flow-through venous flaps with daily intramuscular methylprednisolone injection (30 mg/kg/d); and Group 3 (n=10): negative control composite grafts with the flow-through vein ligated at both edges of the flap. All injections were done 24 hr and 1 hr preoperatively, and for 5 days postoperatively. Observations included gross and histologic examination, and percentage of survival of the flaps on the tenth day. Venous flaps of the animals receiving daily methylprednisolone injections (Group 2) were noted to have statistically significantly improved flap survival ( p<0.05), compared to the control group (Group 1). Flaps in Groups 1 and 2 demonstrated significantly higher survival rates, compared to the composite grafts ( p<0.01). Histologic examination of methylprednisolone-treated animals showed normal stratified squamous epithelium, while complete necrosis was noted in the composite grafts. Untreated flow-through venous flaps demonstrated patchy epidermal sloughing, crusting, and partial necrosis. These results suggest that the survival of potentially ischemic flow-through venous flaps can be enhanced in rabbits by daily methylprednisolone treatment in the perioperative period. Increased tolerance to ischemia and modulation of venous flap microcirculation might be possible mechanisms for this salutary effect.     

Prefabrication of large fasciocutaneous flaps using an isolated arterialised vein as implanted vascular pedicle.

Flap prefabrication represents a new trend in microsurgical tissue transfer. Based on the concept of neovascularisation, in Chinchilla Bastard rabbits (n=40), an isolated venous pedicle dissected from the femoral and saphena magna vein was arterialised by end-to-end anastomosis to the femoral artery at the inguinal ligament. This arterialised venous loop was implanted beneath a random-pattern vascularised abdominal fasciocutaneous flap as large as 8 x 15 cm(2) to investigate the development of neovascularisation at various evaluating times of 4, 8, 12, 16 and 20 days. To prevent neoangiogenesis from occurring between the underlying vascular bed and abdominal flap, a silicone sheet with the corresponding dimension of 8 cm x 15 cm x 0.25 mm was placed and fixed on the abdominal wall. The flap viability and the neovascularisation process in the prefabricated abdominal skin flaps were evaluated by macroscopic observation, blood analysis, selective microangiography and histology. The experimental results showed that newly formed vessels originating from the implanted isolated venous pedicle were evident on the angiograms 4 days after pedicle implantation. In the 8- and 12-day groups, newly formed vessels became larger and some were connected to the originally available vasculature in the abdominal fasciocutaneous flaps. In the 20-day group, entire flaps were perfused by the blood flow supplied from the newly implanted venous pedicles through newly formed vessels and their vascular connections. This study indicated that large flap prefabrication can be created by implantation of an isolated arterialised venous pedicle into a random-pattern vascularised fasciocutaneous flap. Twenty days appears to be the minimal length of time required after arterialised venous pedicle implantation for the maturation of neovascularisation in the prefabricated flap.     

动脉化静脉皮瓣微循环方式的实验研究

目的　探讨动脉化静脉皮瓣移植早期微循环主要方式。方法　选用 2 0只新西兰大白兔 ,随机分为实验组 (动脉化静脉皮瓣 )和对照组 (动脉皮瓣 ) ,每组各 10只。应用显微电视系统直接观察兔耳透明窗的方法 ,在放大10 0 0倍下研究动脉化静脉皮瓣微循环血流。结果　动脉化静脉皮瓣动脉血逆行灌注后主要经细静脉之间的交通支汇入回流静脉。结论　血流由细静脉→交通支→细静脉。是动脉化静脉皮瓣移植早期微循环的主要方式以维持皮瓣早期成活     

The effect of recombinant hirudin on rabbit ear flaps with venous insufficiency

The effect of recombinant hirudin, which is the most powerful antithrombotic agent, on flaps with venous insufficiency was investigated. Oedema and congestion are frequent on flaps, causing necrosis unpredictably. Venous insufficiency and thrombosis are experimentally and clinically more frequent than arterial occlusion. Twenty-one adult New Zealand rabbits were used in this study. Skin flaps (3 × 6 cm) were elevated on a 1-cm-wide pedicle on rabbit ears. The artery, nerve, and vein were exposed and examined with the aid of a surgical microscope. Venous insufficiency was established by cutting the vein and nerve. In the control group, no additional surgical or medical procedures were performed and the ear flap was inset to its original location. Subcutaneous low molecular weight heparin (LMWH; 320 IU/kg) was administered to a second group of rabbits after the same surgery, and recombinant hirudin (2 μg) was administered via the pedicle artery 5 minutes after the vein and nerve were bound and cut in a third group of rabbits. Compared with control and LMWH groups on day 3 and 7, the hirudin-treated group had less hair loss, lower oedema scores and less haematoma formation. Furthermore, a lower size of necrotic areas and an increase in the circulating area on day 7 was found in the hirudin-treated group. In addition, angiography revealed new vessel development (neovascularisation) only in the hirudin group. On histologic sections, hirudin-treated animals had lower oedema, inflammation and congestion scores than animals in the other two groups. Thus, when administered into the ear flap through the pedicle as a pure recombinant preparation, hirudin increased flap survival by its antithrombotic effects and by accelerating neoangiogenesis. Recombinant hirudin may be used in clinical practice to treat flaps with venous problems and to increase survival rates.KEY WORDS: Flap, hirudin, venous insufficiency     

Nitric oxide in flow-through venous flaps and effects of L-arginine and nitro-L-arginine methyl ester (L-NAME) on nitric oxide and flap survival in rabbits

OBJECT: Venous flaps are relatively recent practices in plastic surgery, and their life mechanisms are not known exactly. Partial necroses frequently occur in these flaps; therefore, their survival should be enhanced. Nitric oxide (NO) is an endogenous compound which has recently been dwelt upon frequently in flap pathophysiology, and its effect on viability in conventional flaps has been demonstrated. However, its role in venous flaps is unknown. The purpose of this study is to determine possible changes in the NO level in venous flaps and to investigate the possible effects of NO synthesis precursor and inhibitor on the venous flap NO level and flap survival. MATERIAL AND METHODS: Thirty white male rabbits of New Zealand type, aged 6 months, were divided into 3 groups as control (n = 10), L-arginine (n = 10), and nitro-L-arginine methyl ester (L-NAME) (n = 10). Blood and tissue samples were taken from one ear of 10 rabbits in the control group for the determination of NO basal levels 2 weeks before flap practice. The 3-x-5-cm flow-through venous flaps, which are sitting on the anterior branch of the central vein, were elevated on each ear of 10 rabbits in all groups. After flaps were sutured to their beds, 2 mL/d saline, 1 g/kg/d L-arginine (NO synthesis precursor), and 50 mg/kg/d L-NAME (NO synthesis inhibitor) were administered intraperitoneally in control, L-arginine, and L-NAME groups, respectively, for 3 days. At the 24th postoperative hour, blood and tissue samples were taken from all animals for biochemical analyses. At day 7, flap survivals were assessed. RESULTS: Mean NO levels in the blood following the flap elevation (129 +/- 76 micromol/mg protein) increased in comparison with basal levels (59 +/- 44 micromol/mg protein) (P < 0.06); however, the tissue level remained unchanged. NO levels in the blood in the L-arginine and L-NAME groups were alike compared with the control group. The tissue NO level in L-NAME group (0.08 +/- 0.03 micromol/mg protein) decreased significantly compared to the control group (0.46 +/- 0.36 micromol/mg protein) (P < 0.001). Mean flap survival in the L-arginine group (95% +/- 6) increased according to the control group (61% +/- 14) (P < 0.001), whereas it did not change in the L-NAME group (55% +/- 13). CONCLUSION: In our model of venous flap, NO level in the blood increased, while it did not change in the tissue; L-arginine significantly enhanced flap viability without affecting NO level. Additionally, L-NAME decreased NO level, but it did not affect flap survival. In light of these findings, NO increases in venous flaps; the change in its level does not affect flap survival, though. However, L-arginine enhances venous flap survival if not by virtue of NO.     

Pre-arterialisation of an arterialised venous flap: clinical cases.

Many factors affecting the survival of arterialised venous flaps have been elucidated, both experimentally and clinically. The survival of large arterialised venous flaps has been reported, with varying results. Large arterialised venous flaps with preformed arteriovenous fistulae at the donor sites have been successfully performed in experimental animals. We report the results of repair of skin defects in the extremities with arterialised venous flaps in eight patients. The arteriovenous shunts were created at the donor sites at least 2 weeks before the flaps were harvested. The flap sizes ranged between 4 x 4cm and 9 x 10 cm. Flap survival was between 93% and 100% of the surface area, as shown by digitalised scanning. In addition to the known advantages of venous flaps, such as less bulk, preservation of the main arteries and ease of harvesting, pre-arterialisation makes designing the flap easier due to the noticeable superficial veins. Pre-arterialisation, when used in carefully selected cases, did not prolong the hospital course of the patients.     

Neurocutaneous island flap:: an experimental model using the rabbit ear

The rabbit ear has often been used as an experimental model; however, a neurocutaneous flap has never been described before. The authors examined the reliability of a skin cartilage flap with a pedicle composed only of a sensory nerve with its vascular network in a rabbit model: A 2 x 2-cm cutaneous cartilage flap was harvested on the dorsal side of the ear bilaterally. Vessels were tied and cut on the 4 sides of the flap, including the central auricular artery and vein. The nerve was cut at the distal side of the flap and was "skeletonized" to the extent of 1 cm on the proximal side, meticulously preserving its vascular network. Subsequently, the flap was elevated with the cartilage as a composite flap and was sutured back to its natural site. The authors elevated 28 skin cartilage flaps on the dorsal side of both the ears of 14 New Zealand White rabbits, centered on the central neurovascular axis. All 28 flaps survived. In the control group of 7 rabbits, the artery, vein, and nerve (pedicle) were severed, and the skin cartilage island was sutured back as a composite graft. None of these 14 grafts survived. In 4 additional rabbits, the authors performed a histologic examination 1 day, 3 days, 7 days, and 3 weeks postoperatively of the neurovascular axis after the same skin cartilage flap was harvested. They compared these results with the histologic examination of the nerve of the contralateral nonoperated ear, and noted a marked dilatation and multiplication of blood vessels in the operated ear beginning on day 1 postoperatively. The presence of this neurocutaneous vascularization should be considered when other kinds of flaps (venous flaps or others) are used as experimental models using the rabbit ear.     

Effects of some pharmacological agents on the survival of unipedicled venous flaps: an experimental study.

Clinical and experimental studies have been conducted to improve the survival of venous flaps. As a result of these studies, although various survival mechanisms were raised, none obtained satisfactory information. Venous stasis, and the resultant venous thrombosis, is a factor that decreases the survival of venous flaps. In this study, we evaluated the effects of two antiinflammatory agents, etodolac and etofenamate, on the survival of unipedicled venous flaps. In this study, 35 male New Zealand white rabbits (3,500-4,000 g) (70 ears) were used. Perichondrocutaneous flaps, 3 x 4.5 cm in size, were designed and raised, keeping the central veins intact in the middle of venous flap. Central arteries and nerves were ligated and transected both proximally and distally, to prepare unipedicled venous flaps. A silicone sheet was placed between the cartilage tissue and flap, to prevent blood flow and revascularization beneath. The subjects were divided into seven groups, consisting of five rabbits (10 ears). In the negative control group (group I), the single vascular pedicle of venous flaps, central veins were ligated and flaps sutured into their own place as the composite graft. In the positive control group (group II), after venous flaps were prepared, normal saline, 0.2 mL, was given subcutaneously. In the first of five experimental groups (group III), unfractionated heparin (100 U/day) was given subcutaneously. In the second experimental group (group IV), etodolac (5 mg/kg/day) was given subcutaneously. In the third experimental group (group V), etophenamate (5 mg/kg/day) was given orally through a feeding tube. In the fourth experimental group (group VI), parnaparin (5 anti-Xa U/kg/day) was given subcutaneously. In the fifth experimental group (group VII), nadroparin (5 anti-Xa U/kg/day) was given subcutaneously, about 7 days postoperatively. At the eighth postoperative day, surviving areas of venous flaps were measured, and the results were evaluated by Kruskal-Wallis ANOVA and Mann-Whitney U-test (P < 0.05). Biopsies were also taken from the flaps for histological evaluation of border of necrotic tissue. Surviving areas of unipedicled venous flaps were larger in experimental groups than those in negative and positive control group (P < 0.05). However, comparison of the experimental groups demonstrated no statistically significant difference (P > 0.05). We concluded that all pharmacological agents used in the experimental groups succeeded in increasing the survival of unipedicled venous flaps. Survival of the unipedicled venous flap was higher in venous flaps than that of composite graft, clearly showing the importance of the venous pedicle.