Effects of hematoma on the short-term fate of experimental microvenous autografts

A compliant and biomimetic three-layered vascular graft for small blood vessels

Engineering a small diameter vascular graft with mechanical and biological properties comparable to living tissues remains challenging. Often, current devices lead to thrombosis and unsatisfactory long-term patency as a result of poor blood compatibility and a mismatch between the mechanical properties of the living tissue and the implanted biomaterial. Addressing all these requirements is essential to produce scaffolds able to survive throughout the life of the patient. For this purpose, we fabricated a novel three-layered vascular graft by combining electrospinning and braiding. Mirroring the structure of human blood vessels, the proposed device is composed of three layers: the intima, the media, and the adventitia. The intima and media layers were obtained by sequentially electrospinning silk fibroin (SF) and poly(L-lactide-co-ε-caprolactone), with ratios selected to match the mechanical properties of the native tissue. For the outer layer, the adventitia, SF yarns were braided on top of the electrospun tubes to create a structure able to withstand high pressures. Compliance, Young's modulus and deformability of the obtained scaffold were similar to that of human blood vessels. Additionally, cytocompatibility of the two layers, media and intima, was assessed in vitro by analysing cell metabolic activity and proliferation of endothelial cells and smooth muscle cells, respectively. Furthermore, heparin functionalization of the scaffolds led to improved anticoagulant properties upon incubation in whole blood. The obtained results indicate a potential application of the herewith designed three-layered construct as a vascular graft for small diameter blood vessel engineering.

Technical tips for safe perforator vessel dissection applicable to all perforator flaps

The introduction of perforator flaps by Koshima and Soeda in 1989 was met with much animosity in the surgical community. The flaps challenged conventional teaching and were often branded as being unsafe. Surgeries using perforator flaps are now routinely practiced all over the world, with increasing emphasis on minimizing donor site morbidity, and perforator flaps are becoming the current gold standard. The simple principles and techniques of perforator dissection can be applied to all perforator flaps, provided the surgeon has an intimate knowledge of the regional anatomy. Thus, virtually any piece of skin can be harvested as long as it incorporates a feeding vessel. This article highlights the essential techniques in planning and raising perforator flaps and the common pitfalls to be avoided.

Forearm arterial vein grafting: problems and alternative solutions

We aimed to evaluate patency rates following forearm arterial reconstruction and suggest improvements. Thirty-two vein grafted reconstructions (using saphenous and dorsal hand veins) were evaluated for patency and development of symptoms using clinical examination, Colour-Doppler Sonography and angiography. Overall patency was 59%, with no significant difference between saphenous and dorsal hand veins. Stasis, turbulence, decrease in blood velocity, change in flow pattern, stenosis in the anastomotic area or increase in compliance was detected in 10 patent grafts, but was not associated with symptoms. Six out of 13 non-patent grafted patients had severe or troublesome symptoms associated with accompanying nerve regeneration. To improve patency, careful microsurgical techniques, 'fit vein' and valveless grafts should be used. Dorsal hand veins are most appropriate for short defects. Patency should be evaluated soon after reconstruction.

Reliability of primary vein grafts in lower extremity free tissue transfers

Free flaps transferred to the lower extremity have a higher risk of failure, which may be expected to increase further with the use of vein grafts. The results of 103 consecutive free flaps to the lower extremities of 98 patients who were operated from March 1994 to December 1999 were evaluated to assess the reliability of vein grafts in lower extremity reconstruction. Five flaps were lost and the overall success rate was 95.1%. Eighty-four free tissue transfers in 79 patients were performed for the reconstruction of traumatic cases, and 81 of these flaps were performed in a delayed manner, between 1 week and 4 months after the injury. Interpositional vein grafts were used primarily in 22 flaps--all in traumatic cases--and 21 of them survived completely (95.4%). Primary vein grafts were used both for arteries and veins in 15 flaps and for arteries only in 7 flaps. The most common cause of tissue loss in these patients was a crush injury in earthquake survivors, followed by electrical injuries, gunshot injuries, motor vehicle accidents, and chronic infections. Free muscle flaps in 13 patients, skin flaps in 4 patients, osseous flaps in 2 patients, and temporal fascial flaps in 2 patients were the flaps of choice in vein graft reconstructions. Although a higher incidence of flap loss has been reported with the use of interpositional vein grafts than with regular transfers, and the technical and pathophysiological problems in flap transfers are also high in the lower extremity, the success rate in vein-grafted free flaps did not differ from that of the simple free flap transfers in the current series. This appears to be the result of meticulous preoperative planning and proper selection of recipient vessels during optimal operative conditions.