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Biomedical subjects

J F Vollmar

Publications and source records attributed to J F Vollmar.

At least 37 records · Page 2Linked to original sources
PubMed1989

Aortic aneurysms as late sequelae of above-knee amputation.

The infrarenal aorta was examined by ultrasound in 329 men who had lost a leg in World War II and in 702 war veterans. The groups were similar in terms of age and risk factors for arteriosclerosis. Abdominal aortic aneurysms were found in 5.8% of the amputees compared with 1.1% of the non-amputees. Unilateral flow reduction after leg amputation causes an asymmetrical flow pattern at the aortic bifurcation, and this is probably the main cause of late damage to the aorta.

Aged↗
PubMed1989

New observations on the healing process in prosthetic substitution of large veins by microporous grafts--animal experiments.

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.

Animals↗
PubMed1989

[Aneurysmic transformation of the venous system in venous angiodysplasias of the limbs].

Based on a retrospective evaluation of 107 patients with congenital venous angiodysplasia of the Type Klippel-Trenaunay (n = 76) and Type Servelle-Martorell (n = 31) the frequency and pathogenesis of aneurysm formation in the venous system has been analysed. The vascular patterns include both cylindric ectasias and fusiform aneurysms with an incidence of approximately 40%. Preferred locations are subcutaneous drainage veins, the popliteal, external iliac vein and atypic communicating veins between the superficial and the deep venous system. Complications of the aneurysm such as local thrombosis, recurrent pulmonary embolism or bleeding from rupture were not observed. From a pathogenetic point of view the aneurysm formation in venous angiodysplasias results probably from two causative factors, i.e., a congenital weakness of the venous wall (inborn error?) and an abnormal hemodynamical stress situation. The latter is caused by concomitant malformations of the deep venous system (avalvulia, hypo- and/or aplasia). The persistent intermittent venous hypertension associated with a more or less pronounced increase of the venous volume in the affected venous system of the limb results in a deep venous insufficiency respectively venous reflux disease. Surgery is indicated under two conditions: a) in the presence of aneurysm complications or b) for the elimination of a pathological short circuit flow in some drainage veins. Antireflux surgery, e.g., venous valve transfer form the brachial vein, is up to recently still in a stage of experimental-clinical investigation. The therapy of choice is predominantly conservative, i.e., external compression bandages or stockings to reduce the deleterious effects of a chronic deep venous insufficiency respectively venous reflux disease.

Adolescent↗
PubMed1989

[Value of triad operation in multilevel occlusion].

A triad procedure, i.e., aorto iliac inflow repair + profundaplasty + lumbar sympathectomy, offers a simple and effective approach for revascularisation in patients with multilevel arterial occlusive disease. Approximately 85% of the affected limbs at stage III-IV may return to a stage I or II. Only 10% require an additional distal bypass. Indications, technical aspects and late results are presented.

Aorta, Abdominal↗
PubMed1988

[Aneurysm of the abdominal aorta and leg amputation. A chance coincidence or a pathogenetic correlation?].

A retrospective analysis of 545 patients, operated on between 1970 and 1987 for a closed or ruptured infrarenal aneurysm of the abdominal aorta (AAA), revealed an incidence of 5.1% of unilateral leg amputations among them (20 above, 8 below the knee) during the Second World War. Patients in both groups (with or without amputation) had one or more arteriosclerotic risk factors, their frequency rising with increasing age. There were differences between the two groups in the frequency of certain morphological characteristics in the area of the bifurcation and the terminal aorta affecting the haemodynamics of these regions. Stenosis or occlusion of the ipsilateral iliac arteries may be a possible pathogenetic factor. A prospective study will be required to decide whether the coincidence between leg amputation and AAA is pathogenetic or accidental.

Age Factors↗
PubMed1988

[Reconstructive venous surgery. Principles and technical prerequisites].

The main prerequisites for successful reconstructive venous surgery include (1) critical selection of patients according to morphological and functional diagnostic aspects; (2) optimal surgical techniques; (3) the routine use of intraoperative lumen control in all disobliterative procedures (vascular endoscopy, phlebography); and (4) selective use of protective measures (temporary a.v. fistula, anticoagulans). Expanded PTFE-prostheses with increased microporosity and external ring support are the most suitable substitutes for big veins. Antireflux surgery, such as valvuloplasty, transposition technique and free valvular transfer, is a new approach for the repair of deep venous insufficiency.

Abdominal Neoplasms↗
PubMed1988

[Mesenterial infarct. New aspects of diagnosis and therapy].

Based on a retrospective analysis of 38 patients with mesenteric ischemia treated from 1981-1987, the current diagnostic and therapeutic concepts are presented. Embolic or thrombotic occlusions of the superior mesenteric artery prevailed (34 patients); venous thrombosis (4 patients) and non-occlusive disease (2 patients) occurred less frequent. Old age (70.6 years in average) and a long time interval between onset of symptoms and therapy (25.8 h in average) are responsible for the still high operative mortality (52.9% in the reported series). Of crucial importance is the early diagnosis within the first 6-12 hours, in which the ischemic bowel may mostly retain its viability. Since the application of transfemoral selective angiography or primary laparotomy however far more patients can be cured, compared to the results in earlier days. Especially in case of primary laparotomy the operative strategy aims in the exposition and inspection of the main trunk of the superior mesenteric artery and vein. Extensive ischemia of the intestines mandates, first of all, revascularization of the bowels. By means of exclusive vascular reconstruction or in combination with limited bowel resection (15 patients) the operative mortality could be reduced to 20%. For the intraoperative determination of intestinal viability the fluorescein test is of high reliability. New concepts in the management of mesenteric ischemia such as local arterial application of thrombolytics or spasmolytics open new approaches to improve the therapeutic results. Post-operative monitoring of serum-lactate in combination with clinical findings obviates routinely performed second-look operation.

Adult↗
PubMed1987

[Traumatic ruptures of the thoracic aorta].

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.

Accidents, Traffic↗
PubMed1987

Advances in vascular endoscopy.

In reconstructive vascular surgery several intraoperative investigations are in use to check-up and secure full blood flow restoration (angiography, ultra-sound, electro-magnetic flowmeter etc.). In the last years endoscopical lumen control, introduced 1969 in clinical praxis, could be remarkably simplified and improved. For vascular endoscopy three technical prerequisites are necessary: a) temporary interruption of blood flow using clamps or balloon catheters, b) replacement of the blood by a transparent medium via pressure controlled saline perfusion, c) availability of suitable special endoscopes. The main application of vascular endoscopy includes: a) semi-closed thromboendarterectomy (aorto-iliac or femoropopliteal), b) arterial embolectomy, c) lumen control of inserted grafts including the anastomosis and the distal run-off vessels, d) venous thrombectomy. The availability of small-calibre endoscopes (external diameter: 1.7-2.7 mm) enables the extension of lumen control to small vessel areas such as the tibial and coronary arteries. Compared with angiography vascular endoscopy offers several convincing advantages such as a more reliable three dimensional lumen control, easy performance, saving time and the avoidance of any additional X-ray exposure. Technical faults or overlooked concomitant vascular lesions can be diagnosed and corrected immediately.

Angiography↗
PubMed1986

[Atypical initial manifestation of abdominal aortic aneurysm. The causes of diagnostic and therapeutic errors].

Initial manifestations of an abdominal aortic aneurysm may, depending on its site, morphology and direction of expansion, imitate numerous other intraabdominal diseases, but also lesions of peripheral vessels, vertebral column and spine. In this way they may give rise to errors of diagnosis and treatment. An abdominal aortic aneurysm should be considered especially in case of unclear gastrointestinal bleeding or abnormal intestinal passage (ischaemic colitis; mechanical displacement or compression of the duodenal-jejunal flexure and of the small-intestinal mesentery). In case of massive or recurrent gastrointestinal bleeding, especially in combination with a septicaemia, an aorto-intestinal fistula should be considered in the differential diagnosis. Radicular compression syndrome may be caused by an aortic aneurysm which is usually contained and predominantly suprarenal (to be considered especially once a herniated disk has been excluded by computed tomography). The same is true for unclear bone defects of the lumbar vertebrae (erosion by a penetrating aneurysm). Noninvasive methods, such as upper abdominal sonography, computed tomography and relatively minor invasive transvenous digital subtraction angiography now predominate in the definitive diagnosis of abdominal aortic aneurysm.

Aged↗
PubMed1986

[Carotid endarterectomy in vertebrobasilar insufficiency].

In 45 patients with uni- or bilateral stenoses of the internal carotid artery in association with symptomatic vertebro-basilar occlusive disease 61 carotid endarterectomies had been performed. 28 patients had at least one patent posterior communicating artery (PCA) visualized angiographically (group A). Of these, 26 patients (93%) became asymptomatic or improved postoperatively. Of the 17 other patients in whom the PCA did not visualize by preoperative angiography, only 8 (47%) subsequently became asymptomatic or were improved (p less than 0.05). Thus, identification of the PCA (angiographically or by transcranial Dopplersonography) is important in predicting those patients in whom carotid endarterectomy may be strongly recommended.

Carotid Artery Diseases↗