The interrupted suture technique is most commonly used for microsurgical venous anastomosis. Needle-stitch trauma and intraluminal suture, however, potentially cause vascular wall damage, thrombosis, intimal hyperplasia or even stenosis. Therefore, the present study aimed to show the feasibility and reliability of a modified cuff technique (bipolar anastomosis technique (BAT)) for venous end-to-end anastomosis in a new chicken throat vascular model. In ex vivo experiments, freshly resected chicken jugular veins (N = 96) were used to find ideal BAT time to current settings for venous end-to-end anastomosis. Thereafter, the left jugular vein of chickens (N = 40) was dissected in vivo and subsequently anastomosed using BAT. The quality of anastomosis was evaluated by Doppler sonography immediately, at two hours and at two, six, 12, 16, and 29 weeks after surgery. Additional histological examination took place at two hours (N = 8) and at two (N = 6), six (N = 6), 12 (N = 6), 16 (N = 6) and 29 (N = 6) weeks after surgery. Immediately after surgery (N = 40) and at two hours (N = 38) venous anastomoses were found to be patent in Doppler sonography. Anastomotic rupture caused death in two animals within one hour after surgery. Thrombotic occlusion was found in one animal at six weeks after surgery. In the remaining animals (N = 37) only minimal stenosis which decreased to almost normal levels was sonographically found. The average time needed for anastomosis using BAT was less than two minutes. BAT allows fast venous end-to-end anastomosis in a chicken throat vascular model.

Reconstructive surgery of thoracic defects presents a challenge for the surgeon. With defects of different aetiology and the need for precise localisation of the area to be treated, a broad range of experience is required. We present our interdisciplinary experience in dealing with full thickness thoracic wall defects and intrathoracic cavities. The latissimus dorsi muscle as well as the pectoralis major muscle and their covering skin are the most commonly used flaps in covering an intrathoracic or extrathoracic defect. They have the advantage of being easily and safely dissected. Other flaps such as the greater omentum, serratus anterior, the transverse rectus abodominal muscle (TRAM), and the filet of the arm are less frequently used. Indications and applications of these flaps are reviewed. Our interdisciplinary surgical treatment of thoracic wall defects allows optimal operative excision and reconstruction as well as giving best functional and aesthetic results for the patients.

Six years ago, we published our findings on the effects of low-dose aspirin on thrombus formation at arterial and venous microanastomoses and on tissue microcirculation.1 In that article, we described our research in an animal model; after aspirin administration, we directly observed and measured thrombus formation at microsurgical anastomoses and determined the consequences in the downstream microcirculation. We designed those studies on the basis of our clinical observations that free flap/ replant failure could occur with patent microsurgical anastomoses, which led us to hypothesize that failure could be attributable to occlusion of blood flow in the downstream microcirculation.2,3 Our previous report focused on whether low-dose (1 to 5 mg/kg) aspirin could preserve blood flow at microsurgical anastomoses and in the downstream microcirculation. We hypothesized that the mechanisms of action of aspirin would make it effective in both risk zones. At the microsurgical anastomoses, the effects of aspirin in deactivating cyclooxygenase and inhibiting thromboxane A2 formation would decrease thrombus formation.4 Thromboxane A2 is a potent platelet agonist that causes platelet activation, aggregation, and thrombosis. In the downstream microcirculation, thromboxane A2 has been demonstrated to act on vascular smooth muscle cells, causing vasoconstriction.5 Therefore, the effect of aspirin in inhibiting thromboxane A2 would lead to improved blood flow in the downstream microcirculation. Prostaglandin I2 is a platelet antagonist that inhibits platelet activation and induces vasodilation.6 Low-dose aspirin would not affect endothelial cell and smooth muscle cell cyclooxygenase, leaving prostaglandin I2 production unchanged.7 Our results described in the earlier report demonstrated that low-dose aspirin had beneficial effects on blood flow both at the microsurgical anastomoses and in the downstream microcirculation. Aspirin significantly reduced thrombus formation at the arterial and venous microanastomoses and prevented the decreased microcirculatory blood flow observed in control animals.8

Peter, Frank W. M.D.; Steinau, Hans U. M.D., Ph.D.; Homann, Heinz H. M.D.; Barker, John H. M.D., Ph.D. Author Information

Aspirin causes a coagulation disorder. Desmopressin has haemostatic effects by increasing the plasma levels of coagulation factor VIII and von Willebrand factor. The precise effects of desmopressin on thrombogenesis are not known. In an in vivo model, we investigated the effect of the drug on thrombus formation and platelet function after aspirin use. Male Lewis rats weighing 250-300 g were used. Four groups with 10 animals each were formed: control, aspirin, desmopressin and aspirin + desmopressin. In each animal, the femoral artery was dissected. A thrombogenic vessel injury was created by inverting a full thickness portion of the proximal edge of the incised artery into the lumen. The following parameters were measured: maximum thrombus size, time period until maximum thrombus size was reached and overall platelet function. In addition, the thrombi generated were investigated histologically. Thrombus formation time was significantly shorter with desmopressin compared with the animals treated with aspirin (P < 0.0001) and controls (P = 0.008). Maximum thrombus size was larger in the desmopressin and desmopressin + aspirin groups when compared with the group treated with aspirin only. Overall platelet function was significantly enhanced with desmopressin compared with controls (P = 0.025) and with aspirin (P < 0.0001). The differences were confirmed histologically. In conclusion, desmopressin significantly accelerates thrombus formation in aspirin-treated animals. It can also re-establish thrombus size after the use of aspirin. Overall platelet function is significantly increased by desmopressin.

Adjunct diagnostic techniques might help surgeons to accurately analyse the depth of a burn. However, despite all technical innovations an ideal device for such an application has not been established for routine use as yet. OPS imaging implemented into the CYTOSCAN A/R is a new, recently introduced technique which allows to obtain high contrast images of the microcirculation without the necessity for fluorescent dyes. The aim of the study was to validate OPS imaging as a tool to study microcirculation in skin after burn injury. OPS imaging was applied by no-touch technique and capillary blood flow was videotaped. Subsequent measurements of the microcirculation were performed at the identical site of the burn. Quantitative analysis of the microcirculation was performed off-line using CapImage. OPS imaging produces high quality images of the microcirculation in a burn wound. Data is given as the number of perfused capillaries per observation area (functional capillary density; FCD) [n/cm2]. OPS imaging allows for direct in vivo visualization and quantification of the microcirculation in burned skin. Our preliminary results of the use of OPS imaging in assessing the microcirculation in burns appear promising, and we hope that this novel technique will allow to improve the knowledge of the dynamics of the microcirculation in the pathophysiology of thermal injury.

An intact microcirculation is essential for normal healing to occur. Wound repair may be impaired by various endogenous and exogenous factors, such as reduced microvascular perfusion, infection and debris. In the nonhealing wound, radical surgical debridement is critical. To supplement healing, various ointments are used in clinical practice. Little is known about their effects on tissue perfusion. We have therefore selected two substances widely used, the antiseptic Betadine and the enzyme combination Elase and investigated their impact on the microcirculation and on leucocyte activity, using the cremaster muscle as a model. We found that functional capillary density and arteriolar diameters were significantly reduced by Betadine, whereas leucocyte activity was not affected. In the Elase group, capillary flow and arteriolar diameters were significantly increased, and again leucocyte activity was not changed. The mechanism by which Betadine reduces microvascular flow is believed to be the same as in reperfusion injury. The positive effect of Elase on the microcirculation might be attributed to plasmin, which has been shown to dilate blood vessels.

OPS imaging ermöglicht die Mikrozirkulation in Verbrennungswunden direkt aufzuzeichnen und quantitativ auszuwerten. An 20 Patienten haben wir die Mikrozirkulation in Verbrennungswunden quantitativ erfasst und mit der Operationsindikation korreliert. 74 zweitgradig verbrannte Areale wurden untersucht. Von 31 operierten Arealen waren 27 durch eine gestörte Mikrozirkulation charakterisiert. Die quantitative Analyse der Mikrozirkulation in Verbrennungswunden könnte als additives Diagnostikum in der Verbrennungsmedizin verwendet werden.

The desired shape and position of the nipple-areola complex may be difficult to achieve in vertical scar reduction mammaplasty when using the standard technique of preoperative marking of the so-called mosque-shaped areolar pattern of excision. We describe our modified approach of intraoperative final positioning of the nipple-areola complex by hiding the nipple-areola complex behind the closed vertical incision. Individual positioning at the final part of the operation allows for more predictable results and also for a calculated lower positioning, which enables balance of the potential bottoming-out of the breast, particularly in previously large ptotic breasts. We believe that this modification helps to further improve the results of vertical scar reduction mammaplasty by adding more possibilities for shaping and "last-minute" modifications intraoperatively.

Vogt, Peter M. M.D., Ph.D.; Peter, Frank W. M.D., Ph.D.; Homann, Heinz-Herbert M.D.; Muehlberger, Thomas M.D.; Steinau, Hans-Ulrich M.D., Ph.D. Author Information

Eine Brandwunde besteht aus den Zonen der Nekrose, der Stase und der Hyperämie. Wir haben in einer tierexperimentellen Studie ihre Mikrozirkulation, das Verhalten der Leukozyten sowie den Einfluss von GCSF untersucht. Ergebnisse: 1. Die Nekrose- und die Stasezone nahmen über 24 h signifikant zu. GCSF hatte keinen negativen Einfluss. 2. Leukozytenrollen und -anhaften nahmen über 24 h signifikant zu. GCSF hatte keinen negativen Einfluss. Schlüsse: 1. Der Nachbrenneffekt mit Zunahme der Nekrose- und Stasezone findet auch auf mikrozirkulatorischer Ebene statt. 2. GCSF verschlechtert nicht die Mikrozirkulation der Brandwunde und könnte zusammen mit den bekannten günstigen systemischen Effekten die Gesamtprognose verbessern. 3. Die Hauptdeterminante für die Leukozytenaktivität ist das Verbrennungstrauma, nicht GCSF.

BACKGROUND:Injury of venous vessels during elevated intraperitoneal pressure is thought to cause possible fatal gas embolism, and helium may be dangerous because of its low solubility.METHODS:Twenty pigs underwent laparoscopy with either CO2 (n=10) or helium (n=10) with a pressure of 15 mm Hg and standardized laceration (1 cm) of the vena cava inferior. After 30 s, the vena cava was clamped, closed endoscopically by a running suture and unclamped again. During the procedure changes of cardiac output (CO), heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary artery wedge pressure (PAWP), end tidal CO2 pressure (PETCO2), and arterial blood gas analyses (pH, pO2 and pCO2) were investigated.RESULTS:No animal died during the experimental course (mean blood loss during laceration: CO2, 157+/-50 ml; helium, 173+/-83 ml). MAP and CO values showed a decrease after laceration of the vena cava in both groups that had already been completely compensated for before suturing. PETCO2 increased significantly after CO2 insufflation (P<0.01), while helium showed no effect. Laceration of the vena cava caused no significant changes in PETCO2 values in either group. Significant acidosis and an increase of pCO2 were only found in the CO2 group.CONCLUSIONS:The incidence of gas embolism during laparoscopy and accidental vessel injury seems to be very low. With the exception of acidosis and an increase of PETCO2 in the CO2 group, there were no differences in cardiopulmonary function between insufflation of CO2 and helium.

Leukocyte-endothelium interaction in postcapillary venules plays an important role in reperfusion injury, inflammation, shock, and sepsis. This phenomenon is poorly described in precapillary arterioles. In fact, many researchers have reported no evidence of leukocyte adherence in arterioles whatsoever. Most research has focused on venules of larger rodents, in which observation of the microcirculation, especially arterioles, is limited. We have developed a model which provides a clearer view of these microvessels using the mouse cremaster muscle. This muscle has an approximate thickness of 100 microm allowing images produced by transillumination to be very clear. After vascular isolation, the right cremaster muscle was subjected to 4 h of ischemia, followed by 2 h of reperfusion. The left muscle was not rendered ischemic, thereby allowing it to serve as the animal's own internal control. We observed leukocyte rolling in arterioles in both the ischemic and the nonischemic muscles. Leukocyte sticking was seen in arterioles and venules on both sides, except in control arterioles. The number of rolling and sticking leukocytes on the ischemic side was significantly higher than in controls (P < 0.05) for both arterioles and venules. During the reperfusion period, this number did not change significantly. Transmigration of leukocytes was observed only in venules, but not in arterioles. The number of perfused capillaries was reduced on the ischemic side compared to controls and did not change significantly during the 2 h of reperfusion. Our results demonstrate that leukocyte-endothelium interaction occurs in muscle arterioles of mice. This phenomenon is more pronounced after ischemia and reperfusion, i.e., depends on the extent of tissue insult.

In spite of the extensive experimental work on vascular washout in free flap surgery, an optimal temperature for the washout solution has not been established. This study was designed to determine the effect of the washout solution temperature on the degree to which the microcirculation is cleared of blood. The cremaster muscle flap in the rat was used, in which the microcirculation can be directly viewed and the presence of blood and perfusion parameters within various vessels can be measured during and after washout. Washout was started with a single, high-pressure infusion and continued at 130 mmHg for 15 minutes. The temperature of the washout solution was either 2–3, 20–22, or 35°C. In all three groups, washout cleared the microcirculation almost completely within the first minute. However, we observed that a cold or room temperature washout cleared the microcirculation more completely than a warm washout did. The temperature of the washout solution did not effect post washout capillary perfusion and/or arterial diameters. © 1999 Wiley-Liss, Inc. MICROSURGERY 19:214–222 1999

Severe injury causes immunosuppression, The main contributors are impaired leukocyte function and a cytokine dysbalance. GCSF increases PMN count, function and modulates the inflammatory response. However GCSF may overactivate leukocytes. The purpose of this study is to investigate whether GCSF is able to restore immune competence after severe injury. Lewis rats were divided into three groups: 30% TBSA burn + vehicle; 30% TBSA burn + GCSF (150 mu g rhGCSF); Control. Blood samples were taken for total white cell count, PMNs, TNF alpha and IFN gamma. Leukocyte rolling and sticking were measured in the cremaster muscle microcirculation. Leukocyte diapedesis was investigated by lavage of the abdominal cavity and the lungs. Total white cell and PMN counts in the burn + GCSF group were significantly higher (P < 0.001) than in burn + vehicle animals. Leukocyte adherence and diapedesis were not elevated in the burn + GCSF group as compared to the burn + vehicle group. TNF alpha (P < 0.05) and IFN gamma (P < 0.001) levels were significantly increased in the burn + vehicle animals compared to the burn + GCSF animals. GCSF modifies the immune system, as shown by an increase in white cell and PMN counts and by balancing the overall immune response from proinflammatory to normal, as shown by decreased TNFa and IFN gamma levels. GCSF does not overactivate PMNs (C) 1999 Elsevier Science Ltd and ISBI. All rights reserved.

Strahlenfolgen am Thorax umfassen oftmals Bezirke tiefreichender Gewebsschäden, die an die plastisch-rekonstruktive Chirurgie erhebliche Anforderungen stellen. Eine chirurgische Therapie beinhaltet ein radikales Debridement, möglichst bis in gesundes unbestrahltes Gewebe und anschließend die Defektdeckung mit gut vaskularisierten Lappenplastiken, wobei sich in den letzten Jahren gestielte muskulokutane Lappenplastiken (M. pectoralis major, M. latissimus dorsi, Rektus-abdominis-Myokutan Lappen) durchgesetzt haben. Bei der präoperativen Planung ist sorgfältiges Augenmerk auf das Vorliegen von Lokalrezidiven oder Zweitmalignomen zu legen. Das Debridement muß kompromißlos durchgeführt werden, um rekurrenten Infekten und Fisteln vorzubeugen. Die Wahl des plastischen Deckungsverfahrens hat die Lokalisation sowie Ausdehnung des Defektes insbesondere nach Debridement zu berücksichtigen. Mit diesen Prinzipien lassen sich nicht nur ausgedehnte radiogene Defekte sicher verschließen, sondern in ausgewählten Fällen auch simultane Mammarakonstruktionen durchführen.

Free-flap reconstruction following tumor resection and chemotherapy is used increasingly in sarcoma patients. Granulocyte colony-stimulating factor (GCSF) is used to stimulate polymorphnuclear leukocytes (PMNs). In this study we used a free-flap model to investigate PMN behavior after chemotherapy and GCSF stimulation. Eighteen Lewis rats were divided into three groups: (1) chemotherapy + vehicle; (2) chemotherapy + GCSF; and (3) control. Group 1 received vinblastine; group 2 received vinblastine plus 300 μg rhGCSF. Blood was drawn for total white cell and PMN counts for 9 days. Free-flap surgery was simulated by isolating the cremaster muscle on its pedicle and anastomosing the artery. Leukocyte-endothelium interaction was assessed by observation of leukocytes rolling and sticking. Leukocyte sequestration was measured by counting leukocytes in the lungs and the abdomen. We found that leukocyte rolling and sticking were significantly increased, while sequestration was decreased in the chemotherapy + GCSF group. We conclude that leukocytes-endothelium interaction after chemotherapy and GCSF administration is increased in the microcirculation. This augments the risk of microvascular compromise and subsequent flap failure, as capillary flow. © 1998 Wiley-Liss, Inc. MICROSURGERY 18:290–297, 1998

Introduction: Impaired capillary perfusion may result in flap failure. Platelet emboli, vasospasm and/or polymorphonuclear leukocytes (PMNs) have been identified as possible causes. This study investigates the role of PMNs in causing impaired capillary perfusion in a free-flap model. Methods: Sprague-Dawley rats were injected with either anti-neutrophil serum or saline. Their cremaster muscle was isolated on its pedicle. After arterial repair and reperfusion, capillary perfusion was counted each hour for 6 h. Results: The number of PMNs was significantly reduced in the animals treated with anti-neutrophil serum. However, capillary perfusion did not improve in this group. Conclusions. These results demonstrate that depleting circulating PMNs does not counterbalance the reduction of perfused capillaries, i.e., does not increase their number. It is suggested that reduced capillary perfusion downstream from an anastomotic repair is not mediated by the presence of PMNs in the microcirculation.

Chest-wall reconstruction following irradiation requires a surgical approach that addresses the specific healing disorders associated with irradiation: (1) biopsy of any open wound to rule out recurrence or persistence of tumor; (2) aggressive debridement of all necrotic or infected tissue, especially osteonecrosis of the chest wall; (3) reconstruction with well-vascularized muscle or musculocutaneous flaps. Coverage with muscle flaps provides a very reliable and effective single-stage reconstruction. Most types of flaps employed involve the latissimus, rectus abdominis and pectoralis muscle or musculocutaneous flaps. Rarely, stabilization of the thoracic wall is required, mostly facilitated by nonresorbable mesh. Respecting these principles, the irradiated chest wall can be reconstructed safely and with low morbidity. Plastic reconstructive techniques may also be employed safely to reconstruct the breast simultaneously in irradiated tissue by use of latissimus or rectus abdominis flaps.

Summary Posttraumatic lesions of joints and extremities create a major challenge for an anatomic plastic reconstruction. The experimental and clinical progress in the field of tissue engineering, immunosuppression of allografts and xenografting including methods of genetic engineering provides a potential basis for the reconstruction of whole limbs or anatomical segments with living tissue.