[Invasive diagnostic procedures for insulinomas of the pancreas]. / Invasive Diagnostik bei Insulinomen des Pankreas.

Insulinomas are the most common cause for hypoglycemia with endogenous hyperinsulinism. Insulinomas are the most frequent endocrine tumor of the pancreas and 10% occur as multiple tumors (e.g. multiple endocrine neoplasia type I) or in rare cases as islet cell hyperplasia. A further 10-15% of insulinomas are malignant. Non-invasive imaging modalities, such as computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography (US) and somatoreceptor scintigraphy (SRN) show a lower sensitivity for detection and localization of tumors, because in many cases insulinomas are smaller than 2 cm in size. Invasive pre-operative diagnostic procedures, such as transhepatic peripancreatic venous blood sampling (TPVB) and the intra-arterial calcium stimulation test (ASVS) are much more time-intensive compared to CT, MRI and US with an examination time of 2-3 h but achieve a more exact pre-operative detection and localization with sensitivities mostly greater than 95% and are therefore the diagnostic methods of choice.

[Kyphoplasty : method for minimally invasive treatment of painful vertebral fractures]. / Kyphoplastie : Minimal-invasives Verfahren zur Versorgung schmerzhafter Wirbelkörperfrakturen.

Painful osteoporotic and malignant vertebral fractures are frequent causes of chronic back pain with negative consequences regarding immobility, quality of life, morbidity, mortality, and fracture incidence. The best currently available evidence-based treatment reduces vertebral fracture risk but does not totally prevent follow-up fractures. Kyphoplasty is a causal treatment of pain by internal stabilization that prevents the ongoing pain of constant vertebral (micro-)fracture. The indication for this minimally invasive procedure requires interdisciplinary discussion of the individual case to guarantee technical feasibility, increase the likelihood that kyphoplasty will indeed reduce pain, and embed this procedure in the individual patient's long-term therapeutic concept or treatment of painful vertebral metastases. In addition to internal stabilization of painful vertebral fractures, kyphoplasty seeks to restore lost vertebral height, which appears promising in acute and painful vertebral fractures. Available controlled prospective studies demonstrate long-term patient benefits in terms of pain reduction, mobility, and improved quality of life.

[New microcoil with coaxial administration set for superselective vascular embolization]. / Die neue "Micro"-Spirale mit koaxialem Applikationsset für den superselektiven Gefässverschluss.

Diminution of the "mini"-coil (G-A-W-coil) to a "micro"-coil makes more selective coil embolization possible in vessels down to 1.0 mm. in diameter. Application can be done by the 3.3-F-catheter for superselective embolization of a coaxial application set, consisting of a 7.6-F- and a 3.3-F-catheter. The very thin guide-wire 0.6 mm. in diameter serves as pusher as in other application sets too. In animal experiments 10 superselective embolizations are performed in the vascular system of the superior mesenteric artery in the small infestine of the dog. Vessel occlusion takes place in the same time as in the use of the "mini"- and the standard coil. No complications as coil dislocation or vessel perforation can be reported in the use of the "micro"-coil.

[The effect of selective autoperfusion through an extracorporeal circulation on the formation of arterial collaterals. Animal experimental results (author's transl)]. / Die Wirkung der selektiven Autoperfusion mittels eines extrakorporalen Kreislaufes auf die arterielle Kollateralenausbildung. Tierexperimentelle Untersuchungen.

In 11 mongrel dogs (10-15 kg) with ligated superficial femoral arteries the formation of collaterals induced by increased arterial pressure with an extracorporal circulation was studied. In general anesthesia a teflon tube was inserted into one deep femoral artery. The other end of this tube war introduced through the right carotid artery into the thoracic aorta and arterial blood was drawn by a peristaltic tube pump from the aorta to the femoral artery. Different arterial pressures created by the pump were used to perfuse this hind limb. After 40 minutes perfusion time with 200 mmHG pressure, there was marked increase of collateralization by the deep femoral artery. At the contralateral non treated side, only minimal development of collaterals was visualized. These angiograms demonstrate that collaterals are opened by increased pressure within a short time interval The experimental model might have clinical implisations and accelerate collateral formation in non-surgical treatment of arterial occlusive disease.

[Animal experimental studies on the effect of flow restriction on the thrombogenicity of the Palmaz stent using 111Indium-marked thrombocytes]. / Tierexperimentelle Untersuchungen über den Einfluss der Flussrestriktion auf die Thrombogenität des Palmaz-Stentes mittels 111Indium-markierter Thrombozyten.

The purpose of this experimental study in dogs is to evaluate the influence of restricted flow on the thrombogenicity of balloon-expandable intravascular stents (Palmaz type). We implanted 24 Palmaz stents in the femoral artery of mongrel dogs. 12 dogs experienced a 75% flow restriction by means of an artificial stenosis distal to the start in the outflow tract. We used 111In labelled thrombocytes as a marker for thrombus detection within the stent. The results presented demonstrate that there is no considerable risk of thrombus formation if the stent is implanted into vessels with good outflow tracts and therefore high blood flow velocities within the stent. Under conditions of highly impaired flow, a 68% rate of stent occlusion occur if no anticoagulation therapy is performed. After i.v. administration of 100 IU/kg body weight of heparin the occlusion rate drops to zero. It can be concluded that even under low-flow conditions as a result of a restricted outflow tract situation the Palmaz stent can be implanted without any risk of stent occlusion as long as a sufficient anticoagulation protocol is maintained.

[TIPSS: 10 years of clinical experience]. / TIPSS: 10 Jahre klinische Erfahrung.

UNLABELLED: To demonstrate and document 10 years of clinical experience gathered by us with TIPSS and to discuss achievements, problems and outlook. MATERIAL AND METHODS: The analysis is based on the following parameters: portosystemic gradient; morphological delineation of the portal circulation; determination of the portal perfusion fraction (PPF) and the total liver perfusion (GLP); arterial flow changes; hepatic encephalopathy; incidence of restenotic shunt occlusion and recurrent variceal bleeding. RESULTS: Variceal filling was widely reduced by TIPSS, and significantly reduced portal liver perfusion as assessed morphologically and rheologically. However, there was an immediate onset of compensated liver perfusion by increased arterial inflow. Total liver perfusion did not change significantly. In TIPSS portal decompression was readily achieved, the portosystemic gradient dropping from an average of 24 mm Hg to 10.5 mm Hg. In our series we could not demonstrate an increased incidence of hepatic encephalopathy during the 30-day post-TIPSS period. Early mortality was 4% and early rebleeding rate 3%. The 12-month re-intervention rate based on an invasive portography follow-up protocol was 76%, and the 24-month re-intervention rate was 90%. The definite occlusion rate was below 5%. Beyond a follow-up time span of 24-months the necessity for re-intervention dropped significantly: less than one-third of our patients required some sort of re-intervention. CONCLUSION: The concept of TIPSS represents an individually calibrated H-shunt. The significant reduction of post-TIPSS portal perfusion appears to be compensated by increased arterial inflow. This is reflected by an invasive flow measurement results and by the clinical results. Lethality of TIPSS is low mostly as a result of a refined technique, careful patient selection, follow-up care and meticulous shunt surveillance.

Pulmonary arteriovenous malformations. Case reports and literature review.

Pulmonary arteriovenous malformations (PAVM) represent an uncommon disease with only 500 reported cases. To emphasize the resectional surgical standard, 2 patients with PAVM and pulmonary right-to-left shunt are presented and the optional treatments discussed. One patient had suffered from a cerebrovascular accident. The other patient's diagnosis resulted from a coincidental finding in connection with an unrelated illness. Because of the risk of acutely developing complications, especially disabling or fatal cerebral ischemia, therapy is generally recommended even in asymptomatic patients. The 2 patients presented here were treated by resection. Surgical treatment with a very low risk and parenchyma-sparing technique remains the golden standard for large isolated malformations. In addition to the established and reliable operative therapy, since 1978 catheter embolization is becoming the method of choice with an increasing range of indications in those centers experienced with this technique.

[Treatment of acute iliac artery occlusion by catheter lysis, catheter dilatation and implantation of a new kind of metallic vascular endoprosthesis]. / Die Behandlung eines akuten Beckenarterienverschlusses durch Katheterlyse, Katheterdilatation und Implantation einer neuartigen metallischen Gefässendoprothese.

Methods of interventional radiology have achieved a significant importance for the treatment of acute iliac artery occlusion if either local or general clinical controindications preexclude routine surgical means of vessel repair. The newly developed balloon-expandable metal mesh vascular endoprosthesis is shown to accomplish percutaneously a definitive reconstruction of heavily diseased iliac artery vessel segments which very well compares with the hemodynamic and morphologic aspect of surgical treatment such as thrombectomy combined with TEA or bypass surgery. Both, short and long-term results one year after the implantation of two balloon-expandable metallic vascular stents reflect a much higher efficacy in functional treatment of iliac artery related claudication than a routine percutaneous transluminal angioplasty alone. In addition, it is shown that local lysis based on a standard protocol of selective intrathrombus instillation of urokinase helps to clear totally clogged iliac arteries.

[Spontaneous kidney ruptures--a complication of panarteritis nodosa]. / Spontane Nierenrupturen--eine Komplikation der Panarteriitis nodosa.

Besides renal cell carcinomas and angiomyolipomas panarteritis nodosa (PAN) is a common underlying disorder for spontaneous perirenal hematomas (SPH). Herein we report on 3 cases with PAN associated kidney ruptures where diagnosis of PAN was not known before in 2 instances. The hematoma was identified by computerized tomography (CT) in all patients, nevertheless CT failed to reveal the underlying disorder in any case. In this situation angiography was extremely valuable visualizing multiple renal microaneurysms that are typical for PAN. Operative exploration and drainage of the hematoma was necessary in two patients because of hemodynamic instability. In one patient bleeding could be controlled after an immediate immunosuppressive therapy with prednisone and cyclophosphamide. Due to the high incidence of PAN associated spontaneous perirenal hematomas angiography should be performed in all cases with unclear SPH after CT evaluation. In our opinion an immediate surgical intervention is only indicated in cases with hemodynamic instability. Otherwise a conservative approach including immediate immunosuppression seems justified. Nephrectomy should be avoided whenever possible.

Prediction of immediate and long-term benefit after kyphoplasty of painful osteoporotic vertebral fractures by preoperative MRI.

BACKGROUND: It is unclear if an MR-detectable bone marrow edema is a prerequisite for pain reduction and morphological correction by kyphoplasty. This comparative trial evaluates clinical and radiomorphological outcomes after kyphoplasty of painful osteoporotic vertebral fractures with and without preoperative MR-detectable bone marrow edema for 1 year of follow-up. METHODS: Preoperative MR-images of 45 patients who received kyphoplasty for treatment of painful osteoporotic vertebral fractures were evaluated with regard to presence (n = 27) or absence (n = 18) of vertebral bone marrow edema. Pain scores (VAS 0-100) and radiomorphological measures (midline vertebral height, kyphosis angle) were analysed at baseline, postoperatively and after 12 months. RESULTS: In the "bone edema" group, pain scores improved from 72.7 to 46.8 (postoperative) and 48.0 (12 months, P < 0.001, both). In the group without preoperative bone edema, pain score improved from 70.7 to 60.3 (postoperative, P = 0.013) and to 50.1 (12 months, P = 0.001). Pain scores of both groups were significantly different directly postoperative (P = 0.026), but not after 12 months (P = 0.714). Vertebral height restoration was slightly greater in the "bone edema" group (10.2% vs. 7.8%, P = 0.289). Correction of the kyphosis angle was greater in the "bone edema" group (P = 0.014) compared to the "no bone edema" group (P = 0.838). CONCLUSION: A preoperative MR-detectable vertebral bone marrow edema predicts a better short-term outcome after kyphoplasty, but is not a prerequisite for long-term pain reduction in patients with old, chronically painful osteoporotic vertebral fractures.

Vertebroplasty and kyphoplasty - inefficient treatments for degenerative spine disease.

Osteoporotic vertebral fractures and pathological vertebral lesions are frequent clinical situations causing severe back pain. The pharmacological treatment of the underlying disease and the analgetic treatment of the associated back pain usually do not rid the patient's back pain completely and are insufficient to prevent the fracture-weakened vertebral body from further fracturing with long term consequences for the biomechanical competence of the entire spine. In the last 10 years the minimal invasive treatment options vertebroplasty (VP) and balloon kyphoplasty (BK) have spread quickly because these procedures appeared to be promising treatments to stop the fracture and vertebral lesion associated back pain and to internally stabilize a fractured vertebral body. Numerous published reports on VP and BK appeared to support the notion of an immediate and lasting pain reduction after VP and BK in additon to a prevention of further fracturing of the treated vertebrae. The first three randomized controlled and partly blinded trials have been published this year. Two of these trials demonstrate that VP does not result in a better pain control than a sham operation whereas BK was shown to reduce back pain due to verterbal fractures for at least 12 months. Considering that more than 1.5 million people world-wide have been treated with VP and BK until now this work discusses the recent trials and suggests clinical and academic consequences on the basis of the most recent evidence.