Different types of arteriovenous anastomoses between femoral artery and vein distal to the island groin flap

An experimental study was done in rats in which the animals were randomly divided into four groups. Each group included bilateral standard island groin flaps. The right side flap was used as control. On the left side, after elevation of the flap, different types of arteriovenous connections were constructed distal to the pedicle between the femoral artery and vein. The connection type was a type-C (end-to-end) anastomosis in Group 1; a type-X (side-to-side) anastomosis in Group 2; a type-T a (artery-end-to-vein-side) anastomosis in Group 3; and a type-Tv (vein-end-to-artery-side) anastomosis in Group 4. Flow values in the flaps were measured externally and repeatedly using a laser Doppler flowmeter. Extremity changes, signs of congestive heart failure, flap weights (measured at the end of the study), thrombosis at the anastomosis or distal to it, edema in the flaps, subcutaneous venous stasis, and aneurysm formation in the anastomoses were observed. Histopathologic evaluations were also done. Only the side-to-side anastomosis group showed any aneurysm formation in the distal vein, as well as extremity changes and signs of congestive heart failure in some of the animals. Only the artery-end-to-vein-side group showed distal thromboembolism in some animals. All flaps survived, but there was prominent edema in the flaps of Group 2 and Group 4 animals in decreasing order. All the study flaps demonstrated subcutaneous venous stasis and capsule formation. The authors concluded that although any arteriovenous communication located distal to the pedicle of an island skin flap that connects the arterial to the venous system, bypassing microcirculation, may have some beneficial effects, it is not devoid of some possibly hazardous developments, including edema formation and venous stasis.     

Dorsalis pedis arterialized venous flap for hand and foot reconstruction

Objective:To report the results of repair of skin defects in the extremities with arterialized venous flap harvested from the lateral aspect of the dorsum of the foot.Methods:Six cases of skin and soft...     

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.     

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.     

Comparison of different managements of large superficial veins in distally based fasciocutaneous flaps with a veno-neuro-adipofascial pedicle: an experimental study using a rabbit model

The role of large superficial veins in the survival of a distally based fasciocutaneous flap with a veno-neuro-adipofascial pedicle was studied in a rabbit model. A sural veno-neuro-fasciocutaneous flap model (6 x 2 cm) with a distally based lesser saphenous veno-neuro-adipofascial pedicle (1.5 cm) was established. Fifteen rabbits were randomly divided into three groups with 10 flaps in each group. In group I, the distal lesser saphenous vein was left open (venous inflow remained) after the flap was raised. In group II, the lesser saphenous vein was ligated in the pedicle (no venous inflow). In group III, the venous pedicle was left open in the pedicle, and the proximal end was microsurgically anastomosed to the recipient vein (outflow established). Intravenous pressure, flap survival, and histology were examined. The results showed that the values of intravenous pressure in group I were significantly higher than in group II (P < 0.001). The mean flap survival rate of group III (94.5%) was significantly higher (P < 0.001) than of groups I (22.7%) and II (55.5%). Histology showed that the lesser saphenous vein in group I was extremely dilated and filled with thrombosis. This experiment demonstrated that establishing a superficial venous outflow channel by anastomosis at the proximal end, or interrupting the inflow channel by ligation at the distal pedicle, may significantly improve the survival rate of distally based veno-neuro-fasciocutaneous flaps.     

Proinflammatory cytokines gene expression in skin flaps with arterial and venous ischemia in rats

Infiltration of inflammatory cells is the crucial element in ischemia-reperfusion injury of the microsurgical flap. Cytokines are a large functional group of polypeptide regulatory molecules that influence the activity of various cell types through autocrine and paracrine mechanisms. In this study, expression of selected proinflammatory cytokines was examined in skin flaps with arterial and venous ischemia in the rat model. Fifty-four Sprague-Dawley rats were used in the study. The ischemia of each flap was induced by clamping its vascular pedicle for 6 hr. The flap was then replaced and allowed to reperfuse. All flaps were biopsied immediately post-event, and at 3, 6 and 18 hr after reperfusion. Expression of tumor necrosis factor (TNF-alpha), interleukin (IL-1beta), and monocyte chemoattractant protein-1 (MCP-1) mRNA was determined by RT-PCR in each case. The same number of skin flaps without ischemia was used for baseline gene expression. Results showed that the TNF-alpha expression was significantly up-regulated in the flaps with arterial ischemia at 6 hr after reperfusion. In the flaps with venous ischemia, MCP-1 expression was increased with its peak expression at 3 hr after reperfusion. IL-1beta expression was increased threefold in the flaps subjected to venous ischemia and following reperfusion in 3 hr, but the peak expression in the flap with arterial ischemia was observed at 18 hr after reperfusion. This study delineated the changes in expression of these proinflammatory cytokines in flaps with arterial and venous ischemia reperfusion injury, and showed that cytokine expression was different in the arterial and venous injuries.     

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     

Salvage of the lower extremity free flap using cross-leg venous repair.

This retrospective study was designed to evaluate a salvage technique for free flaps suffering venous congestion by using a cross-leg vein repair in patients with venous-impaired lower extremities. Four free flap reconstructions were performed using the latissimus dorsi muscle to reconstruct soft tissue defects in the lower extremity. The recipient artery was confined to the ipsilateral leg and the venous anastomosis was performed with a long saphenous vein from the contralateral side. The legs were immobilised together by means of an external fixator. All patients were males with a mean age of 31 years. The mean time of pedicle division was 8.8 days (7-10). The mean size of the free flap was 186.5 cm(2). All flaps survived after pedicle division without venous congestion. There were no complications such as joint stiffness or donor site morbidity except for a linear scar. The cross-leg venous repair is a refinement of a salvage procedure for compromised free flaps used in the reconstruction of severe soft tissue defects in vascularly compromised lower extremities.     

Effect of clamp versus anastomotic-induced ischemia on critical ischemic time and survival of rat epigastric fasciocutaneous flap

BACKGROUND: There are many models used to explore ischemic-related phenomena. The rat epigastric fasciocutaneous flap model is the one most commonly used. Critical ischemic time is the maximum ischemic insult that tissue can undergo and still remain viable. Experimentally, ischemia is induced either by clamping the vascular pedicle or by dividing the pedicle then performing microvascular arterial and venous anastomosis. We sought to determine what effect the different methods of inducing ischemia have on the critical primary ischemic time and, thus, flap survival. METHODS: A right 3 cm x 6 cm groin flap based on the inferior epigastric vessels was raised in each rat. Ischemic times of 4, 6, 8, or 10 hours were induced either by placing temporary occlusion clamps on each vessel of the vascular pedicle (island pedicle group) or by ligation and division of the pedicle with subsequent microvascular anastomosis (free flap group). Survival was assessed at 7 days. RESULTS: The primary ischemic time at which one half of free flaps are predicted to die was calculated to be 7.60 hours, compared with 6.09 hours for the island pedicle flaps (p<.05). CONCLUSIONS: Fasciocutaneous flaps undergoing ligation and anastomosis are more resistant to ischemia than are those undergoing clamping of the pedicle. Possible etiologic factors responsible for this experimental finding are discussed.     

Arterialized venous free flaps for soft-tissue reconstruction of digits: a 40-case series

When there is not sufficient local tissue available for reconstruction of one or multiple digital defects, distant flap reconstructions are required. Available thin flaps with defined arterial inflow and venous outflow are limited and require the sacrifice of an arterial pedicle. In addition, a functional limitation can occur at the donor site. During the last decades, experimental and clinical attempts have been made in using venous flaps, based just on the venous network for in- and outflow. A 40-case series of arterialized venous free flaps in soft-tissue reconstruction of the digits and hand is presented. Neovessel formation induced by an intact venous plexus within the flap proved clinically to be the survival mechanism. Postoperative congestion was present in all flaps and subsided within 14 days; 92 percent of all flaps eventually survived. In 57.5 percent of cases, total flap survival was observed; in 17.5 percent of flaps, a superficial epidermolysis occurred, not requiring further surgery; in 17.5 percent of flaps, a full-thickness skin necrosis developed, requiring grafting (minor complication); in 7.5 percent of reconstructions, total flap necrosis was observed. Thus, in the authors' experience, when conventional local flaps are not available, arterialized venous free flaps proved to be a successful solution for soft-tissue reconstruction in digits and hands. The authors present the main indications and advantages of arterialized venous free flaps, emphasizing the essential technical steps and the most frequent pitfalls in treatment.     

Impact of gradual blood flow increase on ischaemia-reperfusion injury in the rat cremaster microcirculation model.

INTRODUCTION: We aimed to evaluate the impact of gradual blood reperfusion on ischaemia-reperfusion injury and to explain the pathophysiology of reperfusion injury in a rat cremaster muscle microcirculation model. MATERIALS AND METHODS: Twenty-four Sprague-Dawley rats weighing 150-200 g were evaluated in three groups. Cremaster muscles were prepared for microcirculatory observations. Group I (n=8, control): no ischemia was induced. Group II (n=8, acute reperfusion): microclamps were applied to the right external iliac vessels for 150 min, then venous and arterial clamps were released at once. Group III (n=8, gradual reperfusion): microclamps were applied to the right external iliac vessels for 150 min, and then the first venous clamp was released; the arterial clamp was opened gradually by a specially designed microclamp holder (Sheey ossicle holding clamp). In all groups, following a wait of 150 min blood flow velocity was measured for 15 min and then the animals were reperfused freely for 1h. Next, red blood cell velocity, vessel diameters, functional capillary perfusion and endothelial oedema index were analysed, and rolling, migrating and adhesing leukocytes and lymphocytes were counted. All observations were videotaped for slow-motion replay. Muscle damage was evaluated histologically. RESULTS: In the acute clamp release group, blood velocities increased up to 600% of their pre-ischaemic values during the post-ischaemia-reperfusion period. The numbers of rolling, adhering and transmigrating leukocytes were significantly higher and histological evaluation revealed more tissue damage in the acute reperfusion group. CONCLUSION: Depending on histological and microcirculatory findings, gradual reperfusion was confirmed to reduce the intensity of reperfusion injury.     

Venous augmentation of the free TRAM flap.

Venous congestion in a free TRAM or DIEP flap when the main pedicle is still patent (both the artery and the vein) is an occasional dire situation. Here, we describe ways of salvaging the free TRAM or DIEP flap from imminent loss. In the last 4 years, we have had three patients who developed venous congestion after the use of the TRAM or DIEP flap for breast reconstruction. This was detected as late as the third postoperative day in our first patient. On exploration, patent arterial and venous anastomoses were found. Fortunately, the opposite pedicle had been dissected and preserved with the flap. The patent congested vein in this pedicle was anastomosed to the cephalic vein using an interpositional vein graft, relieving the congestion. In the other two patients congestion was detected earlier and relieved using the superficial inferior epigastric vein. It has been our policy to dissect a length of the opposite pedicle and/or preserve a length of the superficial inferior epigastric vein or the superficial circumflex iliac vein. These can then be used to augment venous drainage if inadequacy is noted at the end of the operation or during the postoperative period.     

Augmentation of venous drainage by a venous anastomosis for pedicled flaps

Recently several studies have addressed the venous problem and confirmed that venous ischemia is more injurious to tissue viability than arterial ischemia of equivalent duration. There are different methods of managing venous-compromised pedicled flaps. Between June 1996 and November 2003, our center treated two submental, five Becker, nine posterior interosseous, three distally based sural, and three colon pedicled flaps (22 flaps in total), which had venous congestion either at the time of flap elevation or immediately after inset of the flap. These cases of venous congestion were managed with an immediate additional venous anastamosis. After vein anastomosis, venous congestion reduced gradually, then improved, and finally disappeared completely in the postoperative follow-up days with all flaps surviving in their entirety. Reexploration was not required for the microsurgical venous anastomosis. In conclusion, flap necrosis resulting from venous congestion causes prolonged hospitalization, multiple debridements, and additional procedures to cover the exposed structures. Additional vein anastomosis, which is a simple, rapid, and reliable auxiliary procedure, may increase complete flap survival and lead to successful end results, both functional and cosmetic.     

Arterial flap (II): an experimental study in rabbits

Skin flaps are normally characterized by arterial inflow and venous outflow. However, there are several reports about experimental and clinical applications of venous and arterialized venous flaps. On the other hand, some studies evaluated the importance of different pedicle types in prefabricated flaps. It was discovered by chance that a prefabricated free flap, having arterial-only inflow, could be used successfully in eyelid reconstruction. An experimental study on arterial flaps in rabbits showed that an arterial-only inflow was adequate for flap viability until the establishment of venous neovascularization.Presented at the 14th Congress of Turkish Plastic and Reconstructive Surgery, Ankara, Turkey, October 1992     

The Pruitt-Inahara carotid shunt as an assisting tool to anastomose the arterial free flap pedicle to the internal carotid artery in the vessel-depleted neck

Microvascular free tissue transfer in head and neck reconstruction requires suitable recipient vessels which are frequently compromised by prior surgery or radiotherapy to the neck. This article details a new technique of arterial free flap pedicle anastomosis to the internal carotid artery in a vessel-depleted neck. A 63-year-old female was referred because of recurrence of squamous cell carcinoma of the tongue, which involved the left-sided tongue base and pharynx with circumferential involvement of the homolateral external carotid artery. This artery and its branches were excluded as potential recipients. To close the defect after tumor excision, a free vertical rectus abdominis muscle arterial flap pedicle was anastomosed to the homolateral internal carotid artery with the help of a Pruitt-Inahara outlying carotid shunt. The venous anastomosis was performed to the internal jugular vein. The VRAM flap survived without complications. This procedure is to be considered an alternative rescue technique for salvage reconstruction in vessel depleted necks.     

游离胸背动脉穿支皮瓣桥式移植修复小腿软组织缺损

目的总结游离胸背动脉穿支皮瓣或肌瓣桥式移植修复小腿软组织缺损的临床应用效果。方法自2006年9月至2009年1月,应用游离胸背动脉穿支皮瓣或肌瓣桥式移植修复小腿软组织缺损11例,缺损范围4cm×8cm至8cm×22cm。皮瓣切取连带肩胛下与旋肩胛血管,血管蒂呈T形,与健侧小腿胫后动脉行端端吻合,血管蒂用中厚网状游离植皮覆盖。结果除1例术后皮瓣远端发生小的表浅感染,经换药后愈合外,本组皮瓣全部成活。术后随访9个月至3.6年(平均2.9年),没有发现明显的供区功能障碍,供区与受区外形较好,健侧小腿经临床观察与Doppler检查,胫后动脉通畅。结论本方法适用于修复四肢软组织缺损后,患者仅存1条主要动脉者;行桥式游离胸背动脉穿支皮瓣或肌瓣移植不损伤健侧小腿胫后动脉,降低了对供区的损伤。     

How to Fashion a Tram Flap in the Presence of a Lower Midline Laparotomy Scar an experimental study in rats

The transverse rectus abdominis musculocutaneous (TRAM) flap cannot be used successfully in a patient with a pre-existing midline abdominal scar because the area distal to the scar undergoes circulatory failure leading to necrosis. To investigate the usefulness of various procedures to improve the circulation in such a flap, we studied the percentage area survival of experimental abdominal island flaps in five groups of rats with pre-existing midline scar treated by different procedures which depended on the source of blood used to supply the flap (control, arterial, venous, arteriovenous shunt, and delayed, n = 5 in each group). All flaps in the arterial group survived completely. The mean (SEM) percentages of the flaps that survived in the control (17(2)%) and venous (17(1)%) groups were significantly lower than those in the delayed (31(2)%) and arteriovenous shunt (67(6)%) groups (all, p<0.01). These results indicate that preservation of arterial inflow by arterial anastomosis or arteriovenous shunt on the opposite side is important if the flap is to survive across the midline scar. Preservation of the vein in the opposite flap is not essential, because venous outflow is supposed to drain through the midline scar into the epigastric vein of the pedicle without any signs of congestion.     

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.     

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.     

The venous flap - a safe alternative to the simple vein graft in a special situation.

The use of free tissue transfer has evolved to become the mainstay of treatment of tissue defects. The reconstructive surgeon can choose from a wide variety of flaps. Flaps are chosen based on the tissue defect and also on the characteristics of the pedicle in terms of calibre and vessel length. Occasionally situations arise necessitating the use of vein grafts. Vein grafts can be used primarily as part of a planned procedure to increase pedicle length or as a salvage technique following anastomotic complication. We report the use of venous flap instead of a conventional vein graft, for restoring continuity of the arterial flow in the pedicle of a free flap, following resection of a thrombosed segment. A venous flap harvested from the left leg with a cutaneous vein was used in a flow-through fashion to restore the continuity of the arterial inflow to the flap. The venous flap is an ideal option in selected cases instead of a vein graft. This is specifically indicated where there is a shortage of soft tissue to cover the anastomosis. The pedicle can then be covered in a tension-free manner. Thus in addition to extremity wounds, the venous flap can be used safely in salvage of difficult situations in the head and neck area.