静脉皮瓣与桡动脉掌浅支皮瓣修复伴动脉缺损手指创面的疗效对比

目的比较分析静脉皮瓣和桡动脉掌浅支(SPBRA)皮瓣修复伴有指掌侧固有动脉缺损的手指创面的临床疗效。方法回顾自2014年7月至2018年3月伴有指掌侧固有动脉缺损的手指创面40例40指,其中采用静脉皮瓣(A组)修复18例、SPBRA皮瓣(B组)修复22例,均进行门诊随访收集相关资料。采用SPSS 17.0统计软件对其手术时间、皮瓣2-PD、患者满意度、皮瓣外观、供区并发症、皮瓣成活率及患指关节活动度进行分析比较,P<0.05为差异有统计学意义。结果40例皮瓣术后均全部成活,伤口均Ⅰ期愈合。A组手术时间为(78.89±7.36)min,较B组[(97.27±9.26)min]短,差异有统计学意义(P<0.05)。A组和B组分别平均随访11.6、12.1个月,末次随访皮瓣2-PD测量值分别为(7.94±1.55)mm、(6.59±1.65)mm,差异有统计学意义(P<0.05)。手功能活动度:A组,优13例,良5例;B组,优17例,良5例,优良率均为100%。患者满意度:A组,非常满意4例,满意13例,一般1例;B组,非常满意17例,满意5例;皮瓣外观:A组,良16例,差2例;B组,良21例,差1例。两组差异均无统计学意义(P>0.05)。结论伴有动脉缺损的手指创面,静脉皮瓣和SPBRA皮瓣桥接修复均可获得较高的成活率和满意的临床疗效。依据感觉恢复首选SPBRA皮瓣;依据操作难易程度,静脉皮瓣操作相对容易。     

Venous drainage in retrograde pedicle flaps: experimental study in rats

This study was performed to investigate the venous drainage in reverse island groin flaps in a rat model. Two groups of 10 rats were studied. All rats of group A had a groin reverse flap with a complete pedicle (artery and venae comitantes). In rats of group B, an arterial groin reverse flap (artery without venae comitantes) was performed. For the two groups, the perivascular tissue was excised. Nine flaps in the group A and seven flaps in the group B, survived without partial or complete necrosis. Microscopic examination showed venous dilatation in the two groups. There was no significant difference between the two groups. These results confirm that venous drainage of the arterial reverse flow flap without venae comitantes is performed by venae arteriosa. However, venae comitantes probably ensure venous drainage when they are respected.     

Protective effects of monoclonal antibody to intercellular adhesion molecule-1 in venous ischemia-reperfusion injury: experimental study in rats

Flaps with venous occlusion have a decreased survival rate compared with arterial occlusion. It seems that several factors are involved in the etiology of total venous occlusion, including free radicals, edema, thrombosis, and reperfusion injury. In the present study, the authors evaluated the blockage of polymorphonuclear leukocyte endothelial adhesion by using a monoclonal antibody to the intercellular adhesion molecule 1 (ICAM-1) ligand to prevent venous ischemia-reperfusion injury in rat epigastric island flaps. A skin flap (3 x 4 cm) supplied by the superficial epigastric artery and vein was harvested unilaterally in 40 male Wistar rats. Total venous occlusion of the skin flap was achieved. Arterial inflow was left intact. Rats were randomly divided into four groups (n = 10). In Group 1; rats were intravenously pretreated with 0.5 ml of 0.9 percent normal saline 15 min before applying a venous clamp, and the flaps were subjected to 6 hr of venous ischemia. In Group 2; rats were intravenously pretreated with 0.05 mg of monoclonal antibody to the intercellular adhesion molecule 1 (0.20 mg/kg) in 0.5 ml of 0.9 percent normal saline 15 min before applying the venous clamp, and the flaps were subjected to venous ischemia as in Group 1. In Group 3; rats were pretreated as in Group 1, and the flaps were subjected to 8 hr of venous ischemia. In Group 4; rats were pretreated as in Group 2, and the flaps were subjected to 8 hr of venous ischemia. The flaps were assessed histologically and by measuring viable and non-viable areas on postoperative day 7. Flap measurements revealed that blocking the action of ICAM-1 IN VIVO by administering monoclonal antibody significantly attenuated ischemic injury after 6 or 8 hr of venous occlusion.     

Further investigation of secondary venous obstruction.

The first ischemic insult a tissue suffers is primary (1 degree). A second ischemic episode, such as thrombosis after free tissue transfer may be regarded as secondary (2 degrees) ischemia. The current study investigated 2 degrees ischemia in rodent epigastric flaps. Flaps were elevated in 50 Sprague-Dawley rats: group 1 had 5 hours 1 degree venous ischemia induced by placement of microvascular clamps; group 2 was like group 1, except venous continuity was re-established by venous anastomosis after resection of the venous segment previously microclamped; group 3 had 15 minutes of 1 degree ischemia, 24 hr later 5 hr of 2 degrees venous ischemia was induced by placement of microvascular clamps; group 4 was like group 3, except the venous segment was excised. Necrosis was evaluated on postoperative day 7. Both secondary ischemic groups had significantly less flap survival than the corresponding primary ischemic groups (P less than 0.001 for both). Resection of a portion of the vein and subsequent microanastomosis did not reduce flap survival (NS). Secondary venous ischemia of 5-hr duration is poorly tolerated by rodent skin flaps. There was no difference in flap survival in those flaps whose veins were clamped for 5 hr compared to those flaps whose clamped venous segments were resected and re-anastomosed.     

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.     

The use of long synthetic microvascular grafts to vascularise free flaps in rabbits

A 5 cm length of 2 mm internal diameter (i.d.) synthetic, expanded polytetrafluoroethylene (PTFE, or Gore-Tex) vascular graft was used to connect 25 rabbit inferior epigastric flaps to the contralateral femoral vessels. In 15 animals an expanded PTFE graft connected the opposite femoral artery to the flap while the ipsilateral venous drainage remained intact. In the remaining 10 animals an expanded PTFE graft was used to replace the venous drainage of the flap and connected to the opposite femoral vein while the ipsilateral femoral artery supplied the flap. Flap survival and graft patency were evaluated over 3 weeks. Ten of 15 flaps with intra-arterial grafts survived at 3 weeks (67%). Only 27% (4/15) of their supplying grafts remained patent for 3 weeks, although 67% (10/15) were patent at 10 days. All 10 flaps, where expanded PTFE grafts replaced venous outflow, failed within 36 hours. At exploration these grafts were thrombosed or collapsed. In conclusion, currently available 2 mm (i.d.) expanded PTFE vascular graft cannot maintain patency in a low blood flow circulation supplying an isolated free flap.     

Internal jugular vein versus external jugular vein anastamosis: implications for successful free tissue transfer

BACKGROUND: Microvascular free flaps are becoming the reconstructive option of choice for many head and neck defects. Many previous studies have examined factors predicting free flap survival. No study has compared differences in free flap survival when anastomosed to the internal or external jugular systems. METHODS: Retrospective review of all free flaps performed at an academic medical center by a single head and neck microvascular surgeon during the period July 1995 to December 1999. Flaps were closely monitored postoperatively and taken back to the operating room urgently for arterial insufficiency or venous congestion. RESULTS: On hundred fifty-six free flaps were performed during this time period. Sixty-five free flaps were anastomosed to the external jugular (EJ) vein and 86 to the IJ system (62 to the proximal common facial vein, 17 end-side on the IJ, and 7 to other branches). Five had either two venous anastomoses or were anastomosed to other veins and were excluded from statistical analysis. Six (4%) vascular thromboses occurred; 5 were venous and 1 arterial. Success by group was 99% for IJ anastomosis (1 arterial thrombosis) and 92% for EJ anastomosis (5 venous thromboses, p =.03). Urgent anastomotic revision and reperfusion salvaged 5 of the 6 flaps (overall success 99%). CONCLUSIONS: Although the overall success rate (96% success with 99% success with salvage) is comparable to other large series, microvascular free flaps anastomosed to the external jugular vein failed at a significantly higher rate than those anastomosed to the IJ system. This suggests that the IJ system should be used as a recipient vessel when feasible.     

Effect of vein grafting on the survival of microvascularly transplanted muscle flaps

Since vein grafting is often required during transplantation of free muscle flaps but is associated with a higher failure rate than those flaps transplanted with primary anastomoses, we sought to compare primary repair with the use of vein grafting in an experimental setting. We transplanted the gracilis muscle to the contralateral side in 98 rats using four different methods of vessel repair. In the Control group (n = 28), both femoral vessels were anastomosed primarily. In Experimental Group 1 (n = 25), the femoral artery was anastomosed with an epigastric vein graft and the femoral vein was anastomosed primarily. In Experimental Group 2 (n = 25), the femoral vein was anastomosed with a femoral vein graft and the femoral artery was anastomosed primarily. In Experimental Group 3 (n = 20), both femoral vessels were anastomosed with vein grafts. The Control and Experimental Groups 1–3 survival rates were 89.3, 76.0, 84.0, and 70.0%, respectively; none of the experimental group survival rates was significantly different from that of the control (P < 0.5). This study demonstrates that the use of size-matched, interpositional vein grafts in the arterial or venous pedicle of the rat gracilis muscle flap during transplantation did not significantly decrease flap survival as compared to primary arterial or venous anastomoses. If the observed failure rate persisted with expansion of the study groups to 60–100 animals each, the failure rate of flaps with vein grafts would be significantly lower and comparable to failure rates reported in some clinical series. The large numbers necessary to significantly show this decrease make this model impractical for further studies © 1997 Wiley-Liss, Inc. MICROSURGERY 17:512–516 1996     

Comparison of normal and venous flaps. An experimental study]

The abdominal skin of 135 rats was fashioned to be normal on venous flap for investigating the difference in quality of the two. For normal flap, the right superficial epigastric artery was used to serve as the nourishing vessel and the left superficial epigastric vein the draining one. For venous flap, the right superficial epigastric vein was made to be the nourishing vessel and the left superficial epigastric vein the draining one. The flap in group I was fed with blood from the distal end of the femoral vein; the flap in group II was supplied with blood from the distal end of the femoral artery; and the flap in group III was nourished with blood from the femoral artery. It demonstrated that the venous flaps in group I were better in quality than the normal flaps in terms of survival rate, elasticity and size of ulcer. However, the results in group II and group III were quite different. As for clinical use, it would be all right to cover small wound with venous flap; while repairing large defect, particularly in exposed part or area near a joint, normal flap should be of the choice.     

A microcirculation observation of the venous flaps]

This article presented the observation results of microcirculation of 84 island venous flaps performed on the ears of 42 rabbits. The survival rates of 5 groups divided by differently handling the vessel pedical of the flaps were: 1. maintaining artery and venous 90.36%. 2. maintaining distal and proximal venous 86.29%. 3. only maintaining proximal venous 75.71%. 4. only maintaining distal venous 28.75%. 5. ligating all vessels O(P < 0.01). The results of blood flow examined by laser Doppler and the number of micrangium counted by microcirculation microscope were decreasing upon the sequence of the above groups (P < 0.05). We found that there were exact microcirculation in the venous flaps of group 2, 3, 4, but the blood flow in these groups, especially the group 4, were slower than the group 1.     

结扎伴行静脉对逆行岛状皮瓣存活的影响

目的 以新西兰大白兔隐动静脉逆行岛状皮瓣为实验模型,探讨结扎血管蒂伴行静脉干对逆行岛状皮瓣存活的影响.方法 将10只新西兰大白兔两侧后肢左右随机分为2组,每组10个皮瓣,进行同体对照.建立隐动静脉逆行岛状皮瓣实验模型(面积3 cm×3 cm,血管蒂长4 cm,血管蒂周围保留1 cm宽筋膜).对照组:血管蒂部不做任何处理;实验组:在放大10倍手术显微镜视下于血管蒂的两端分别结扎伴行静脉干,使2根伴行静脉干完全闭塞.术后每天观察皮瓣颜色、肿胀情况.术后1周测皮瓣成活率,并切取血管蒂进行组织学观察.结果 术后两组皮瓣均有较明显的肿胀,实验组皮瓣肿胀更为明显.两组皮瓣平均成活率比较,对照组为(92.7±12.1)%,实验组为(46.8±38.3)%,差异有统计学意义(t=3.61,P＜0.01).两组皮瓣蒂部均可见扩张的微血管,高度肿胀导致坏死的皮瓣,在其蒂部扩张的微血管内可见血栓形成.结论 血管蒂的伴行静脉结扎使皮瓣更易发生静脉危象,导致皮瓣坏死.微血管内血栓形成可能是导致皮瓣静脉回流障碍的又一重要因素.

Abstract：

Objective To evaluate the effect of ligating venae commutantes in the pedicle on the survival of reverse-flow island flaps. Methods Ten New Zealand rabbits were used. Reverse flow island flap based on the saphenous artery and vein was created on both hind limbs,with a total of 20 flaps. The size of the flap was 3 cm×3 cm with a 4 cm long vascular pedicle containing 1 cm strip of connective tissue. These flaps were randomly divided into 2 groups of 10 flaps each. In group Ⅰ,the vascular pedicle (1 saphenous artery and 2 venae commutantes) was raised and its sheath was not disturbed,maintaining communicating and collateral branches intact. In group Ⅱ,the 2 venae commutantes were ligated with 8-0 suture at both ends of the pedicle under 10X microscope and the connective tissue was maintained intact. The color and congestion of flaps were observed daily. Flap survival rate was measured after one week. The vascular pedicle was harvested and observed histologically. Results The flaps began to appear obviously swelling after blood oozing stopped. The extent of swelling was more severe in group Ⅱ than in group Ⅰ. Flap survival rate of group Ⅰ (92.7±12.1)% was significantly higher than that of group Ⅱ (46.8±38.3)% (t=3.61,P<0.01). Histological examination revealed lots of dilated venules in the vascular pedicle. The amount of dilated venules in group Ⅱ was more than that in group Ⅰ. Lots of thrombi could be seen in the dilated venules in the pedicle of completely or partially necrotic flaps. Conclusion Venous crisis takes place more easily in flaps without venae commutantes,resulting in flap necrosis. The venous thrombosis may be the other important influencing factor for necrosis of reverse-flow flaps.     

Prior elevation of vascular island skin flaps: intolerance to ischemia caused by venous obstruction

Previous experiments in our laboratory have shown that prior elevated flaps, those elevated 24 hr prior to complete ischemia, are more tolerant of the ischemic insult than acutely ischemic flaps that have had no prior elevation. In the current study, the effect of prior elevation was observed on tolerance to ischemia caused by venous occlusion alone. Under these conditions, limited blood flow may be possible via the unclamped artery, so a state of partial ischemia exists. After seven hours of venous obstruction, acutely elevated flaps had a 50 percent survival rate at postoperative day 7. This was significantly better (p less than 0.005, chi 2 test) than the 0 percent survival rate for prior elevated flaps for the same period of venous obstruction. It is speculated that the more rapid generation of cytotoxic free radicals during the period of partial ischemia is more detrimental to the prior elevated flaps that have greater blood flow, than to the controls.     

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     

Experimental studies of skin flaps with subcutaneous veins

The authors have previously reported that skin flaps with subcutaneous veins nourished by arterial or venous inflow survived, despite being sited on recipient beds with poor circulation. In these previous studies, experimental models were based on axial pattern flaps of rabbit ears. However, for clinical application, there are problems in the use of axial pattern flaps with central vessels. This report classifies skin flaps with subcutaneous veins and produces experimental models that are suitable for clinical application and investigation of survival rates. Thirty-seven rabbits (74 ears) were used in this study. A 3.0-cm x 4.5-cm skin flap with only a "passing" vein (one that traveled through the tissue without major branches to that tissue) was raised at the level of the perichondrium on the dorsum of the auricular cartilage. The flaps were divided into three groups: Group A--composite flaps (n = 10); Group B--totally venous perfused flaps (n = 30); and Group C--afferent arterialized venous perfused flaps (n = 34). More than 80 percent of the flaps became necrotic in Group A. In Group B, 18 of 20 survived with partial superficial necrosis and two became more necrotic. In Group C, 18 of 21 flaps survived with superficial necrosis and three became more necrotic. Microangiographically, as concerns the "passing" veins in Groups B and C flaps, all of the flaps survived with only superficial necrosis. The skin flaps with subcutaneous veins survived as total venous perfusion flaps (TVPF) and as arterialized afferent venous perfusion flaps (AAVPF) even though the artery was not included in the flap. The experimental model is suitable for the investigation of the clinically unconventional flap.     

Biochemical analysis of the venous flap in the dog.

There has been great interest stimulated by reports on factors influencing the survival of skin flaps which possess only venous inflow and outflow, i.e., venous flaps. The present study serially (Days 1, 2, and 4 postoperatively) observed several biochemical factors which might affect flap survival. ATP levels were measured to assess endogenous energy stores, malonyldialdehyde (MDA) and xanthine oxidase (XO) to estimate free radical production, superoxide dismutase (SOD) to quantify antioxidant defenses, and edema to measure inflammatory changes. Eighteen thighs on nine dogs were assigned randomly to one of three groups: full-thickness skin grafts, flaps based solely on the saphenous artery and vein (AV flaps), or flaps based solely on the saphenous vein (venous flaps). These were regarded as being mostly ischemic, totally perfused, and partially ischemic, respectively. Control skin biopsies were obtained adjacent to surgical sites. AV flaps and control skin were similar in all respects. Venous flaps compared with skin grafts were significantly less edematous (P less than 0.01) had less MDA and XO (P less than 0.05), but no significant differences in SOD and ATP levels. However venous flaps had significantly less ATP than AV flaps (P less than 0.01). Thus venous flaps survive despite depletion of ATP levels. These results suggest that decreased free radical production and lessened edema may be important factors in promoting ultimate survival of venous flaps.     

Role of perivenous areolar tissue in the viability of venous flaps: an experimental study on the inferior epigastric venous flap of the rat.

This study was performed to investigate how the perivenous areolar tissue affects survival of the rat inferior epigastric venous flap model designed by Yuen and Leung (1991). Five groups of flaps were studied; group A--flap based on an inferior epigastric vein and areolar tissue; group B--flap with a skeletonised vein; group C--control, nonvascularised flap; group D--flap based on perivascular areolar tissue alone; group E--flap with a skeletonised artery and vein. Each group included 40 flaps; 20 of them had a silicone sheet placed under the flap, the other 20 did not. All flaps of group E survived. The success rate of group A with and without a silicone sheet was 60% and 90% respectively. All flaps of the other groups (B, C, D) necrosed. Histological examination of the pedicle showed that many minute vascular channels (single-cell-layered capillaries) were present apart from the inferior epigastric vein. This result confirms the importance of the perivenous areolar tissue in perfusion of the skin island, at least, in the inferior epigastric venous flap in the rat.     

The effect of trimetazidine on the survival of rat island skin flaps subjected to ischemia-reperfusion injury

The effect of trimetazidine (TMZ) on flap ischemia-reperfusion injury was investigated in rat inferior epigastric artery flaps. Twenty-six rats, divided into four experimental groups-nonischemic group (group 1, N = 5), ischemic control group (group 2, N = 7), preischemic TMZ-treated group (group 3, N = 7), and postischemic TMZ-treated group (group 4, N = 7)-were used. Rat inferior epigastric artery flaps were rendered ischemic by occluding the feeding femoral artery, and they were reperfused by releasing the clamps after 11 hours in groups 2 through 4. Group 3 rats were given TMZ (3 mg per kilogram, intravenously) diluted in saline before application of the clamp, and group 4 rats were given TMZ before clamp removal. Flap survival was scored on postoperative day 8. All flaps in the nonischemic control group (group 1) survived completely. The ischemic control group (group 2) demonstrated a 6.3 +/- 4.3% survival area. In the preischemic TMZ group (group 3) the mean survival area was 76.9 +/- 6.1%, and in the postischemic TMZ group (group 4) it was 76.8 +/- 5.6%. TMZ-treated flaps showed a significant increase in survival area regardless of the time of administration (p = 0.001, group 3 vs. group 2; p = 0.001, group 4 vs. group 2). This finding suggests that TMZ has a beneficial effect on the prevention or treatment of arterial ischemic flaps.     

扩张预制对跨区供血轴型皮瓣的桥联效应

目的 探讨扩张预制对跨区血管构筑以及跨区供血轴型皮瓣成活率的影响,为提高跨区供血轴型皮瓣的成活率,以及开发新的跨区供血轴型皮瓣供区提供研究思路.方法 取12只成年健康五指山猪,体重20～30kg.实验分为A、B两部分,每部分6只,均采用双侧自身对照设计.实验A:每只动物随机取一侧为对照组,另一侧为扩张组,两侧以腹中线为界;对照组为侧腹壁形成的方形皮瓣,扩张组为扩张预制皮瓣.实验B:每只动物随机取一侧为扩张组,另一侧为延迟组;扩张组为扩张预制皮瓣,延迟组为单纯扩张器植入不扩张的延迟皮瓣.皮瓣制备后及时行皮瓣动脉造影,术后2周行皮瓣成活率测定.结果 实验A扩张组皮瓣动脉造影显示,扩张皮瓣旋髂深动脉和腹壁上动脉之间吻合支数量多,管径粗,旋髂深动脉和腹壁上动脉系统能清楚显影;对照组造影剂通过3～4条较细的吻合支到达腹壁上动脉终末支及终末穿支,腹壁上动脉系统大部分不能显影.实验B扩张组旋髂深动脉和腹壁上动脉间完全沟通,吻合支丰富,动脉口径较粗;延迟组造影剂通过少量不规则吻合支由旋髂深动脉达腹壁上动脉,但充盈不顺畅,充盈灌注范围较扩张组小,且动脉口径也小于扩张组.实验A扩张组及对照组皮瓣成活率分别为90.16%±3.61%及72.67%±5.35%;实验B扩张组及延迟组皮瓣成活率分别为92.08%±3.30%及80.79%±4.52%,组间差异均有统计学意义(P<0.01).结论 扩张预制能有效提高跨区供血轴型皮瓣的成活率,桥联效应为其主要作用机制.     

The influence of sildenafil on random skin flap survival in rats: an experimental study.

Sildenafil (Viagra), a selective and specific inhibitor of cyclic guanosine monophosphate (cGMP) phosphodiesterases (PDEs), is currently marketed for the treatment of erectile dysfunction. Sildenafil is a potent and highly selective PDE-V inhibitor and enhances smooth muscle relaxation in human. Systemic arterial and venous smooth muscle cells contain PDE-V and nitric oxide (NO) which is a major mediator of relaxation of the smooth muscle cell. The aim of the present study is to investigate, in a rat model, the potential effect of sildenafil on survival of random pattern skin flaps. For this purpose, 32 Sprague-Dawley rats were used and a McFarlane-type caudally based skin flap was designed on the dorsum of the rat (2.5 x 8 cm). Rats were divided into four groups: One control (Group D), and three treatment groups (Groups A, B, C). Sildenafil was administered orally to the experiment groups; Group A: 3 mg/kg/single dose a day, Group B: 10 mg/kg/single dose a day and Group C: 10 mg/kg/twice dose a day. The areas of flap necrosis were measured in each group. The extent of viable flap areas were expressed as a percentage of total flap area, and differences were studied by Completely Randomised Experimental design. The areas of necrosis of skin flaps decreased depending on sildenafil dose, but viability of the flaps treated with 3 mg/kg/day was not different than the control group. The flaps receiving 2 x 10 mg/kg/day sildenafil gave the highest (P < 0.01) survival rate. As a conclusion, sildenafil may have a dose dependent effect to increase flap survival in random skin flaps.     

Microcirculatory hemodynamics of the rat cremaster muscle flap in reduced blood flow states

Recent studies revealed that muscle and musculocutaneous flaps have the lowest peripheral resistance and best flap survival. The critical values of flow rates responsible for this survival have not been established. The authors evaluated the effect of prolonged arterial flow reduction on flow hemodynamics and muscle flap survival, independent of neovascularization using the rat cremaster muscle island flap model for microcirculatory studies. Muscle flaps were implanted into a transparent Plexiglas chamber to allow prolonged observation of the microcirculation. Twenty-six male Sprague-Dawley rats were studied in three experimental groups. In group I (control; no occlusion), after flap isolation, the cremaster muscle was implanted into the tissue chamber and microcirculatory measurements were performed from day 0 to day 3. In group II, after flap isolation, flow in the main feeding artery (the iliac) was reduced with a silk suture loop between 47% and 62%. In group III, arterial flow was reduced between 63% and 80%. Vessel diameters, red blood cell velocities, number of perfused capillaries, and number of rolling, sticking, and transmigrating leukocytes were reduced daily for each rat. Immediately after flow reduction, mean arteriolar (A1) diameters were significantly smaller in group II (25%) and group III (29%) compared with the controls (p<0.05). This reduction was confirmed by a drop in red blood cell velocities of 37% and 58% in groups II and III respectively (p<0.05). At day 1, more than 60% of group III flaps had no arterial flow, whereas normal flow was observed in control flaps for as long as 3 days. In addition, the number of perfused capillaries dropped significantly (by 42%) in group II flaps after 3 days (p<0.05). The authors conclude that continuous arterial blood flow reduction exceeding 60% of the normal volume, independent of angiogenesis, is incompatible with flap viability in the rat cremaster muscle model.