1) Traumatic rupture of the thoracic aorta is most frequently caused by a traffic accident with deceleration. Approximately 80% of these patients die immediately. In 29 patients (1973-1986) reaching surgical treatment, all aortic lesions were located at the aortic isthmus (28 covered and 1 free rupture). 25 (86%) of them had serious associated injuries of the head, other thoracic or intraabdominal organs and/or the extremities. A seat belt could not prevent the deceleration injury of the aorta but reduced associated injuries of the head and the intraabdominal organs. 2) The widely accepted surgical rule that every diagnosed traumatic aortic rupture should have an immediate surgical repair is no longer acceptable. In all patients with a clinically and angiographically stable covered rupture of the aorta with serious associated injuries and symptoms of shock the surgical treatment of the aortic lesion should be undertaken with delayed emergency after some hours or several days. This changed surgical concept is based both on the rarity of secondary free rupture of the aortic lesion and on the chance to stabilize the circulatory condition by a primary shock treatment including the surgical elimination of other sources of blood loss. The group with such a delayed aortic vascular repair (n = 12) showed a remarkably improved outcome with reduced operative mortality and reduced risk of paraplegia (47% vs. 25% respectively 35% vs. ca. 10%). None of these patients with a delay up to 17 days for vascular repair developed a secondary free aortic rupture. Up to recently this risk has been obviously overestimated on the basis of earlier studies in the sixties. 3) The immediate repair of the aortic rupture with its high operative mortality and high rate of ischemic paraplegia can be restricted to a few exceptional cases with a secondary free rupture in the hospital. The transvenous DSA is the best approach for an early diagnosis and for the surgical decision to perform vascular repair immediately or with delay.

Based on the experimental experiences in more than 180 implantations of different materials as venous substitutes segments of the inferior vena cava have been replaced in 34 dogs by Polyurethane (low microporosity) and modified e-PTFE prostheses (increased microporosity of 60 microns and 90 microns fibril length). The 12 months patency rate didn't differ between both tested optimized materials and ranged from 43 to 50%. After a follow-up of 12 months the grafts were taken out and analysed by light, immunofluorescence microscopy, scanning and transmission electron microscopy. In addition a new technique of microcorrosion casts was used for SEM-analyses. As a result a transmural microvessel system in the microporous meshwork of the prostheses with multiple orifices at the inner surface of the grafts could be demonstrated. Complete endothelialization was only observed in e-PTFE prostheses of high microporosity (greater than 60 microns fiber length). There is strong evidence that a full tissue incorporation of microporous artificial grafts mainly depends on a sufficient primary intramural deposit of blood components (fibrin, platelets, leucocytes), which initiates cell invasion from the surrounding tissue, accompanied by a highly developed microvessel network. A multifocal endothelialization takes place from the numerous microvascular orifices on the inner surface of the prostheses. Other sources such as pannus invasion or adhesion of multipotent cells from the blood stream play probably a very limited role.

Beside traditional techniques (light, immunofluorescence, transmission electron (TEM)- and scanning electron microscopy (SEM), a new more sensitive method for producing microcorrosion casts using a polyester-based resin has been developed. The SEM analyses of the microcorrosion casts of alloplastic vascular grafts was realized in an absolutely stable stage of polymerization. For the first time, a transprosthetic vascularization could be shown in great three-dimensional detail. The importance of a complete and rapid endothelialization of artificial vascular grafts is discussed.

For major limb amputation in patients with occlusive arterial disease, the peripheral amputation level (at the knee or below the knee) is the most important factor in obtaining an optimal functional result and reducing the relatively high operative mortality of above knee amputation. In the study presented, measurement of transcutaneous oxygen tension has proved to be a helpful tool in realizing this therapeutical principle. Comparison with another group of amputees without pO2 measurement indicated that the ratio of above-knee to below-knee amputation could be changed from 2:1 to 1:2. The reduced number of above-knee amputations also resulted in a decrease in operative mortality (7.1% vs 11.4%). The optimal value of pO2 in the lower leg is in the range of 40-45 mm Hg. With this prerequisite, primary stump healing may be expected below the knee. For amputation at the knee and above the knee, the primarily used borderline value of 30-35 mm Hg has proved sufficient. The pO2 values were in good correlation with the arteriographic finding of a patent deep femoral artery, but there was no clear correlation with the ankle pressures found preoperatively by Doppler ultrasound. The sensitivity of the transcutaneous pO2 method is still limited because it mainly reflects the perfusion quality of the skin and the subcutaneous tissue, but no the quality of the blood supply in the subfascial tissue layers. Tissue histography with micro-Pt electrodes offers a new, but invasive approach to measurement of the actual pO2 level in the underlying muscle as well [3].