[Vascular surgical training concept for military surgeons in Germany]. / Gefäßchirurgisches Ausbildungskonzept für Militärchirurgen in Deutschland.

BACKGROUND: Due to the increasing threat of terrorist attacks and assassinations even in Europe, the interest in management of severe vascular injuries, which, with an increased incidence of 10% are to be expected with such penetrating wounds, is also growing; however, with increasing subspecialization in surgery there is a threat that the know-how in vascular surgery will become lost among non-vascular surgical specialists. Therefore, the Germany military established an educational program, the so-called DUOplus concept, to ensure that future military surgeons acquire and retain the experience and skills to fulfill the demanding role of a deployed surgeon. OBJECTIVE: The DUOplus concept of the German Medical Forces is introduced with a special focus on vascular surgery training. RESULTS: All trainee German military surgeons attain a second specialization alongside general surgery. This residency includes several courses in various surgical specialties as well as a 12-month rotation in a vascular surgery department. The core elements of vascular trauma training are two practical courses on life-like models. In these courses, which were developed especially for the needs of non-vascular surgeons in hands-on training, open surgical techniques and damage control measures including resuscitative endovascular balloon occlusion of the aorta (REBOA) are taught on suitable models and intensively practiced. CONCLUSION: All surgeons potentially confronted with traumatic and iatrogenic vascular injuries should have some basic competence in the management of vascular trauma. Especially the courses in vascular surgery for non-vascular surgeons offer such a skill set for every surgeon. Next to the German military surgeons, the courses are attended more and more by civilian and military surgeons from different surgical specialties and nationalities.

[Improve your skills!: evaluation of a 2.5-day basic course in vascular surgery for surgical trainees]. / Besser und schneller! : Evaluation eines 2,5-tägigen gefäßchirurgischen Grundkurses für ChirurgInnen in Weiterbildung.

BACKGROUND: The traditional surgical training in the operating room (OR) is often complemented by participation in workshops and on simulators. The foundation Vascular International offers basic courses for vascular surgery techniques with training on pulsatile circulation, lifelike anatomical models. The aim of this study was to assess the efficacy of a 2.5-day intensive course on basic skills in vascular surgery. MATERIAL AND METHODS: A total of 24 participants (67% male with an average age of 35 years) performed a vein patch-plasty before and after the basic vascular surgery instruction course. Endpoints of the study were the time needed for suturing and the technical quality, which were evaluated by two course trainers on a scale of 0-10. Furthermore, the participants were asked to evaluate their own technical competence. The statistical analysis was carried out using MS Excel (t-test and analysis of correlation). RESULTS: A significantly shortened time for the suturing (19.5 min versus 14.1 min, p < 0.001) and improved quality of the vein patch were found after the workshop (p < 0.05) with a high correlation between the two observers (r = 0.885). The participants also evaluated their own surgical competence better at the end of the training but there was no correlation between the self-assessment and the quality of the patch (r = 0.146 before and r = 0.109 after the workshop). CONCLUSIONS: A significant improvement in the time needed for suturing and the quality of the vein patch-plasty was shown in this study. Further studies are necessary to demonstrate the long-term success and possible shortening of the learning curve in hospitals with professional training. With regard to the current curriculum of surgical trainees in Germany basic vascular surgery courses should be considered as a potential valuable part of the surgical common trunk.

[Clinical requirements of aortic imaging]. / Klinische Anforderungen an die Bildgebung der Aorta.

Modern imaging modalities, especially noninvasive cross-sectional imaging techniques, have advanced dramatically in recent years and are now the backbone of pre- and postoperative evaluation of aortic pathologies. The planning in particular, but also the aftercare following endovascular aortic reconstructions, make heavy demands on physicians. It is necessary to select the method of examination that is best suited to the pathology concerned and to apply it to the patient in an individual manner. Ultrasound is the examination of choice for screening and follow-up of infrarenal aneurysms. Transesophageal echocardiography and magnetic resonance angiography are used in diagnosis, in intraoperative navigation during the implantation of endografts and in follow-up of patients with thoracic aortic aneurysms and aortic dissections who have undergone conservative treatment, with very high sensitivity and specificity. The use of MRA is restricted by the long time needed for an examination, metal artifacts and limited availability. DSA has been largely superseded in the diagnosis of aortic pathologies by CTA, but as yet retains its role in intraoperative imaging of the anchorage regions of endoprostheses. Selective demonstration of postoperative internal leaks with subsequent therapeutic embolization is a further area of use for DSA. CTA, including so-called image postprocessing, has taken over the prime role in imaging of the aorta. Disease-specific diagnostic algorithms are useful and necessary in day-to-day clinical practice.

Intermittent claudication secondary to a traumatic arteriovenous fistula.

Arteriovenous fistula (AVF) formation is a recognized complication of arterial trauma. A 63-year-old man with no known risk factors for atheroma and a history of a 20-year delay in the diagnosis and treatment of a traumatic AVF presented with right calf claudication (maximal walking distance = 150 m). A duplex ultrasound scan and a magnetic resonance angiography showed an aneurysmatic dilatation and partial thrombosis of the infrarenal aorta and the right leg feeding arteries. Selective angiography revealed a complete occlusion of the right popliteal artery in the segment 2 and the infrapopliteal arteries with good collateral formation in the lower leg. At this time, there is no indication for infragenual arterial revascularisation in this patient. Instead, therapy consists of exercise training and antiplatelet therapy. We concluded, that peripheral microembolism from the aneurysmatic aorta, iliac or femoral arteries is most probably the reason for the popliteal occlusion in this patient, representing a rare, nonatherosclerotic cause of claudication.

Local versus global interactions in nonequilibrium transitions: A model of social dynamics.

A nonequilibrium system of locally interacting elements in a lattice with an absorbing order-disorder phase transition is studied under the effect of additional interacting fields. These fields are shown to produce interesting effects in the collective behavior of this system. Both for autonomous and external fields, disorder grows in the system when the probability of the elements to interact with the field is increased. There exists a threshold value of this probability beyond which the system is always disordered. The domain of parameters of the ordered regime is larger for nonuniform local fields than for spatially uniform fields. However, the zero field limit is discontinous. In the limit of vanishingly small probability of interaction with the field, autonomous or external fields are able to order a system that would fall in a disordered phase under local interactions of the elements alone. We consider different types of fields which are interpreted as forms of mass media acting on a social system in the context of Axelrod's model for cultural dissemination.

[Early transfer from intensive care does not influence clinical results of carotid endarterectomy]. / Limitierte Uberwachung nach Karotisthrombendarteriektomie. Frühverlegung aus der Uberwachungseinheit beeinflusst nicht das klinische Ergebnis.

The purpose of this prospective observational study was to examine the necessity of intensive care after carotid endarterectomy (CEA). In consideration of the neurological stage and comorbidities, morbidity and mortality after early transfer from the intensive care unit (ICU) were examined. The CEA patients were assigned preoperatively to short or long monitoring. Those with symptomatic stenosis ranking > or =2 (stroke within 6 weeks before surgery) and ischemic areas in cCT were observed overnight (long) in the ICU. Within 5.5 months, 100 consecutive patients had received 107 CEAs. Preoperatively, seven of these (6.54%) were assigned to ICU overnight monitoring. 14 patients (13%) needed postoperative over night ICU. We observed no perioperative stroke or mortality in the 107 consecutive CEAs. We could not detect any risk factor in preoperatively determining the length of postoperative ICU monitoring. This prospective, single center study showed that, after CEA, it is safe to monitor patients for only a short period (4-8 h) in the ICU. Morbidity and mortality after early transfer to the regular ward did not increase.

XX male: a rare cause of short stature, infertility, gynaecomastia and carcinoma of the breast.

We present a case of an XX male with carcinoma of the breast and primary infertility. He was admitted to hospital with recurrent chest pains, but a history of surgery for breast carcinoma, gynaecomastia and the finding of bilaterally atrophied testes, coupled with the fact that he had never fathered children, necessitated further investigations. Chromosomal analysis showed a 46, XX male genotype with a normal X chromosome and an abnormal X chromosome formed by translocation between the short arm of one X chromosome and the Y chromosome. By using fluorescence in situ hybridisation, the patient proved to be SRY positive, the sex-determining region of the Y chromosome. In this rare genetic abnormality, males retain normal phenotype but they are generally of short stature, have gynaecomastia, and may have genital anomalies. They are infertile and at increased risk of developing carcinoma of the breast. This seems to be the first documented case of carcinoma of the breast in an SRY positive XX male. This particular case illustrates the need for all cases of male breast cancer to undergo full endocrinological assessment, especially in the presence of genital anomaly or infertility.

Improvement of carotid blood flow after carotid endarterectomy--evaluation using intraoperative ultrasound flow measurement.

OBJECTIVES: to examine the relationship between the degree of extracranial internal carotid artery (ICA) stenosis and changes in the ipsilateral ICA blood flow after carotid endarterectomy (CEA). MATERIALS AND METHODS: in a prospective study we studied 51 patients with unilateral 60-99% ICA stenosis (median degree 84%, asymptomatic stenosis n = 13, symptomatic stenosis n = 38). The degree of ICA diameter stenosis was determined by ex-vivo plastination of the surgically removed atherosclerotic specimen and video-assessed planimetry. Intraoperative transit time ultrasound flow measurements of the carotid arteries were performed before and after CEA. Blood flow changes were assessed by mathematical approximations. Statistics were done by use of the Wilcoxon signed Rank test. RESULTS: common carotid artery (CCA) and ICA median blood flow increased after CEA from 370 and 130 ml/min to 450 and 282 ml/min, respectively (p <.001). The relative increase of ICA blood flow was 5% and 18% for 60-69% and 70-79% ICA stenosis (n.s.) but 70% and 247% for 80-89% and 90-99% stenosis (p <.001 each). Mathematical evaluation (fourth-polynomal function) determined a significant increase of carotid blood flow after CEA in ICA stenosis of > or =82.3%. CONCLUSIONS: in the absence of severe contralateral ICA occlusive disease a significant increase of ipsilateral ICA blood flow by CEA can be expected in patients with an ICA stenosis of > or =82.3% (linear degree of stenosis, ECST criteria).

The Carotid Surgery for Ischemic Stroke trial: a prospective observational study on carotid endarterectomy in the early period after ischemic stroke.

OBJECTIVE: The purpose of this study was to examine the safety of carotid endarterectomy (CEA) within 6 weeks after a nondisabling carotid-related ischemic stroke. Endpoints were the perioperative stroke or mortality rate and the incidence rate of cerebral bleedings. METHODS: This prospective observational multicenter trial was performed in community and university centers. One hundred sixty-four hospitalized patients with nondisabling carotid-related ischemic stroke were included. The patients were identified clinically with the modified Rankin scale (initial neurologic deficit grade >/= 2, n = 160). Four patients with evidence of ischemic territorial infarction on cerebral computed tomographic (CT) scan but no persisting functional deficit were also included. CEA was performed within 6 weeks after stroke. Neurologic examinations were performed initially, before surgery, 3 days after surgery, and 6 weeks after CEA. Worsening of more than 1 grade on the Rankin scale was considered as a new stroke or stroke extension. Unenhanced CT scans of the brain were performed before and after surgery. CT scans were evaluated blind to clinical patient data. Statistical analysis included univariate and multivariate analysis. RESULTS: The combined stroke or mortality rate within 30 days after CEA was 6.7%. Ten patients had a new ipsilateral stroke or stroke extension, and one patient died after surgery of a myocardial infarction. One patient (0.6%) had parenchymatous cerebral bleeding, and in 10 patients, hemorrhagic transformation within the preexisting ischemic infarction was detected but no infarct extension was observed. In the multivariate analysis, American Society of Anesthesiology (ASA) grades III and IV and decreasing age were significant predictors for an increased perioperative risk. Patients with a higher risk profile (ASA classification grades III and IV) had a high perioperative risk when CEA was performed within the first 3 weeks (14.6% versus 4.8% beyond 3 weeks). Patients without severe concomitant diseases (ASA grades I/II) had a low perioperative risk of 3.4% if CEA was performed within the first 3 weeks. CONCLUSION: Early CEA within 6 weeks after a carotid-related ischemic stroke can be performed with a perioperative stroke or mortality rate comparable with the results reported in the European Carotid Surgery Trial and the North American Symptomatic Carotid Endarterectomy Trial. The risk of parenchymatous bleeding is low. ASA grades III and IV and decreasing age were predictive of an increased perioperative risk, especially if CEA was performed within the first 3 weeks. Patients at low risk can undergo operation safely within the first 3 weeks. Individual patient selection in an interdisciplinary approach between neurologists, anesthesiologists, and vascular surgeons remains mandatory in these patients.

Grading of internal carotid artery stenosis: validation of Doppler/duplex ultrasound criteria and angiography against endarterectomy specimen.

OBJECTIVES: duplex ultrasound has replaced angiography prior to carotid endarterectomy (CEA) in many institutions. However, the indications for CEA are based on angiographically controlled studies and widely accepted ultrasound criteria do not exist. Consequently, the reliability of Doppler and/or duplex ultrasound to predict a high-grade ICA stenosis has to be proven. DESIGN: prospective validation study. MATERIALS: one hundred and fifty carotid bifurcations assessed by ultrasound and selective angiography and 68 acrylat outcasts of carotid specimen after eversion CEA. METHODS: ICA stenosis was measured angiographically according to the ECST criteria. Combined Doppler acoustic standard criteria (CDASC), peak systolic frequency (PSF), peak systolic velocity (PSV) and end-diastolic velocity (EDV) served as criteria for the ultrasound assessment. These criteria and the results of angiography were compared to the degree of ICA stenosis determined by specimen measurements. RESULTS: the median degree of ICA stenosis as assessed by angiography (82%, range 56-97%) and CDASC (83%, range 50-99%) corresponded well to the specimen measurements (80%, range 50-95%). The sensitivity of angiography and CDASC to predict a 70-90% ICA stenosis (ECST criteria) compared to the specimen measurements was 88% and 95%, respectively. The positive predictive value (PPV) reached 92% and 96%, respectively. CDASC were equivalent to angiography and were superior to the best single frequency or velocity parameters. If CDASC do not indicate a >/=70% ICA stenosis in spite of a PSV >/=180 cm/s and/or an EDV >/=50 cm/s, angiography may detect patients with a >70% ICA stenosis. CONCLUSIONS: CDASC are valid in the quantification of high-grade ICA stenosis. They are more reliable than single velocity and/or frequency measurements. However, if velocity criteria and CDASC do not agree, angiography should be performed.

The use of antibiotic-containing bead chains in the treatment of chronic bone infections.

The implantation of gentamicin polymethylmethacrylate (PMMA) chains or minichains into infected osteomyelitic cavities is a well-established local antibiotic therapy supplementary to radical debridement. The gentamicin concentrations achieved at the site of infection are far above the MICs for most common pathogens in chronic osteomyelitis. Serum and urine concentrations are low, and nephrotoxic and ototoxic side-effects of this form of gentamicin application are not to be feared. Under local antibiotic therapy with gentamicin PMMA chains, primary wound healing as in aseptic surgery can be expected. Prolonged systemic antibiotic therapy is unnecessary. In a series of 405 cases, a success rate of 90.4% was obtained.

Beyond Hebb: exclusive-OR and biological learning.

A learning algorithm for multilayer neural networks based on biologically plausible mechanisms is studied. Motivated by findings in experimental neurobiology, we consider synaptic averaging in the induction of plasticity changes, which happen on a slower time scale than firing dynamics. This mechanism is shown to enable learning of the exclusive-OR (XOR) problem without the aid of error backpropagation, as well as to increase robustness of learning in the presence of noise.

Pigmented thymic carcinoids: a clinicopathological and immunohistochemical study of two cases.

Two cases of pigmented thymic carcinoids are presented. The patients were two men, 32 and 47 years of age. The two patients were asymptomatic and the tumor was discovered on routine chest radiographic evaluation. The tumors were treated by surgical excision in both patients. Grossly, they presented as tan-white tumors without evidence of necrosis or hemorrhage or any visible pigmentation. Histologically, the tumors were characterized by a monotonous proliferation of tumor cells arranged in a trabecular or nesting pattern. The tumor cells showed moderate amounts of pale eosinophilic cytoplasm, round to oval nuclei, and inconspicuous nucleoli. Mitotic activity varied from three to eight per 10 high-power fields. In addition, both tumors showed prominent areas of intra- and extracellular dark pigment deposition. The pigment reacted positively with the Fontana-Masson stain and was negative for iron stain. Immunohistochemical studies performed in one case showed immunoreactivity of the tumor cells for chromogranin, Leu 7, and keratin. Synaptophysin and P53 immunostains were negative. Clinical follow-up was obtained in one patient who was alive and well 10 years after surgical resection. The presence of abundant melanin pigment in thymic carcinoids highlights an important pitfall for diagnosis in these tumors that should be taken into consideration in the evaluation of anterior mediastinal lesions.

Emergency carotid endarterectomy.

OBJECTIVE: Evaluation of the therapeutical efficacy of emergency carotid endarterectomy (CEA) in neurologically unstable patients. PATIENTS AND METHODS: Three groups of a consecutive series of 71 emergency CEAs performed from 1980 to July 1998 were classified: (1) acute onset of severe stroke (n = 16), (2) progressive stroke/stroke in evolution (n = 34), and (3) crescendo transient ischemic attacks (n = 21). Cerebral coma, cerebral haemorrhage, and major ischemic stroke established in cranial computed tomography scans were contraindications for surgery. The neurological outcome was assessed by the modified Rankin scale. Long-term survival and long-term stroke recurrences were analyzed. RESULTS: The recovery/minor stroke rates (Rankin 0-3) in acute stroke, progressive stroke, and crescendo transient ischemic attacks were 56.3, 76.4 and 80.9%, respectively; the combined major stroke/mortality rates (Rankin 4-6) were 43.7, 23.6 and 19.1%, respectively. Intraoperative angiography in 39 patients detected early carotid reocclusions in 2 and intracranial embolism in 7 patients. Local application of thrombolytic agents (n = 5) may contribute to a better neurological outcome in emergency CEA. Life table probabilities of major strokefree survival were 74.5, 71.6, and 53.7% after 1, 2, and 5 years, respectively (including perioperative strokes). Life table probabilities to suffer no stroke recurrence during follow-up were 96.7, 96.7 and 85.3%, respectively (perioperative strokes excluded). CONCLUSIONS: Emergency CEA may be worthwhile in selected patients. Completion angiography is mandatory. Emergency CEA should be included in therapeutic strategies for ischemic stroke.

Primary neuroendocrine carcinomas of the thymus.

Primary neuroendocrine carcinomas of the thymus are rare and comprise a wide spectrum of lesions ranging from well-differentiated to poorly-differentiated neoplasms. The classification of such tumors in the thymus is still controversial. By convention, the better-differentiated examples have been traditionally designated as thymic carcinoids and thought to represent the mediastinal counterpart of carcinoid tumors in other foregut locations. However, recent studies have shown that such neoplasms, when arising in the thymus, exhibit a much more aggressive behavior than those originating at other locations. We therefore consider these lesions to represent fully malignant neoplasms that fall within the spectrum of neuroendocrine carcinomas. The designation of well-, moderately-, or poorly-differentiated thymic neuroendocrine carcinoma is therefore favored for these tumors in the present review. Because such tumors may often adopt unusual morphological appearances, it is important to distinguish them from other more common conditions presenting at this location that may exhibit similar histological features. The clinicopathologic, immunohistochemical, and differential diagnostic features of these tumors in the mediastinum are discussed.

Adult posttraumatic osteomyelitis of the tibial diaphysis of the tibial shaft.

Osteomyelitis of the diaphysis of the tibia in adults is an uncommon but disabling condition. It occurs principally in patients with complex fractures of the tibial shaft in which devitalized bone becomes infected either with a single strain of a virulent organism or with multiple organisms. The outcome of treatment depends on the assessment and management of three interrelated factors, which are the vitality and stability of the bone, the virulence and antibiotic susceptibility of the infecting organism, and the condition of the soft tissues. The impact of the infection on the patient's vitality is of great importance. Successful management depends on control of inflammation, excision of dead bone, and stabilization of the skeleton. Interlocking nailing and local antibiotic treatment are particularly successful strategies. In the future, modification of the inflammatory response with local tissue mediators may become an important adjunctive therapy.

Regional intestinal blood flow and nitric oxide synthase inhibition during sepsis in the rat.

OBJECTIVE: Regional circulatory changes in intestinal mucosa were evaluated after the onset of septic shock and the effect of nitric oxide (NO) inhibition on mucosal blood flow was investigated at different locations along the intestine. SUMMARY BACKGROUND DATA: The response of intestinal blood flow to different physiologic and pharmacologic stimuli is known to vary along the intestine, but limited data are available on regional alterations in intestinal blood flow during septic shock. These regional variations in intestinal blood flow could become important because NO inhibition might restore the circulation of one segment of the gut or exacerbate ischemia that may be occurring concomitantly in another segment of the intestine. METHODS: Mucosal blood flow was studied with fluorescent microspheres in conscious unrestrained rats before and 2, 4, and 6 hours after lipopolysaccharide (LPS, 20 mg/kg intraperitoneally) induced sepsis in the presence and absence of the nitric oxide synthase inhibitor N(G)-nitro-L-argininemethylester (L-NAME, 5 mg/kg subcutaneously). RESULTS: Control mucosal blood flow was significantly higher in the ileum than in the duodenum, jejunum, or colon. During LPS-induced sepsis, mucosal blood flow to the ileum decreased and perfusion to the remaining gut was preserved. This was accompanied by hypotension throughout the experiment. L-NAME administration during sepsis prevented hypotension and decreased mucosal blood flow to all segments of small intestine at 2 hours. In this group, mucosal blood flow to the proximal small intestine but not to the ileum returned to baseline levels at 4 and 6 hours. L-NAME alone decreased mucosal blood flow to the small intestine throughout the experiment. CONCLUSIONS: This study indicates that mucosal blood flow alterations during septic shock vary along the intestine, with a significant change only in the ileum, suggesting that perfusion in the small intestine is dependent on physiologic NO production.

[Computer-based training exemplified by the carotid artery]. / Computer-based Training am Beispiel der A. carotis.

The purpose of computer-based training (CBT) is interactive use of multimedia components, such as text, graphics, animation, sound, digital slide shows, and videos. This CD-ROM illuminates different aspects of carotid surgery: cerebrovascular insufficiency, sonographic and neuroradiological diagnostics, indications and results of carotid surgery in the literature, perioperative complications and new developments such as interventional procedures. Digital imaging (60 minutes of video sequences and 250 graphics) especially focus on operative standard procedures (conventional and eversion technique) and alternative methods. CBT is an evolving supplement to improve education programs in vascular surgery.

Hypotension during septic shock does not correlate with plasma levels of nitric oxide metabolites in the conscious rat.

Hypotension following administration of lipopolysaccharide may be due to excessive production of the potent vasodilator nitric oxide brought about by induction of nitric oxide synthase. The purpose of this study was to determine in conscious, fasted rats what role nitric oxide played in lipopolysaccharide-induced hypotension. When examined by Western immunoblot analysis, inducible nitric oxide synthase immunoreactivity was detected in the aorta at 3 hours and increased over time following administration of intraperitoneal lipopolysaccharide (20 mg/kg). When compared with saline-treated control rats, significant hypotension was observed at 2, 4, and 6 hours following lipopolysaccharide treatment. Blood pressure at 2 hours did not differ significantly from that at 6 hours. Using the Griess reaction to quantify plasma levels of nitrates and nitrites as an index of systemic nitric oxide production, an augmentation in the formation of these nitric oxide metabolites was demonstrated at 4 and 6 hours but not at 2 hours. Subcutaneous administration of the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (5 mg/kg) prevented lipopolysaccharide-induced hypotension, an effect reversed by subcutaneous L-arginine but not D-arginine (350 mg/kg). However, nitric oxide synthase inhibition did not attenuate the ability of lipopolysaccharide to increase plasma nitrate/nitrite levels. These data indicate that lipopolysaccharide-induced production of nitric oxide metabolites does not correlate with lipopolysaccharide-induced hypotension.