A portable shield for a neutron howitzer used for instructional and research purposes.

Neutron howitzers are routinely used in universities to activate samples for instructional laboratory experiments on radioactivity. They are also a convenient source of neutrons and gammas for research purposes, but they must be used with caution. This paper describes the modeling, design, construction, and testing of a portable, economical shield for a 1.0 Curie neutron howitzer. The Monte Carlo N Particle Transport Code (MCNP5) has been used to model the (239)PuBe source and the howitzer and to design the external neutron and gamma shield.

Placement of endovascular stent-grafts for emergency repair of acute traumatic aortic rupture: a single-centre experience.

The aim of this retrospective study was to evaluate mid- and long-term results of endovascular stent-graft placement for emergency repair of acute traumatic thoracic aortic rupture. From 1996 through 2005, 22 consecutive patients (mean age: 38.7 years) underwent endovascular repair of acute traumatic thoracic aortic rupture located at the aortic isthmus in most cases. All patients were at high surgical risk due to severe associated injuries. The endografts were inserted via femoral or iliac artery access under fluoroscopic guidance. Follow-up was performed postinterventionally, at 6 and 12 months and yearly thereafter, and included clinical examination and computed tomography (CT) scans. Technical and clinical success rates were 86.3%. Mean follow-up was 31.7 months. Three patients developed early type I endoleak due to the inability of the rigid graft to adapt to the curved aortic contour. In two of them conversion to open surgery was necessary. One patient had late type I endoleak and died. No other complications were observed. The outcome was successful in most patients. The mid- and long-term results of our current study are promising. However, early type I endoleak represents a problem, especially in adolescent patients with a marked curvature of the aortic arch.

Technical and clinical success of infrarenal endovascular abdominal aortic aneurysm repair: A 10-year single-center experience.

OBJECTIVE: The aim of our retrospective study was to review our single-center experience with aortic abdominal aneurysm (AAA) repair retrospectively. MATERIAL AND METHODS: From 1995 to 2005, 70 consecutive patients affected by AAA were treated by endovascular stent-graft repair. Mean follow-up was 23.9 months. Follow-up investigations were performed at 6 and 12 months and yearly thereafter. Five different stent-graft designs were compared to each other. Primary technical success (PTS), assisted primary technical success (APTS), primary clinical success (PCS) and secondary clinical success (SCS) were evaluated. RESULTS: All over PTS was achieved in 94.3%, APTS in 97.1%, PCS in 61.4%, APCS in 64.3% and SCS in 70%. There were 3 type I endoleaks, 25 type II endoleaks, 4 type III endoleaks, 8 limb problems, 5 conversions to open surgery, 10 aneurysm sac expansions and 14 device migrations. Patients with newer generation devices showed better results than patients with first generation prosthesis. In addition results were better for grafts with suprarenal fixation (versus infrarenal fixation) and grafts with barbs and hooks (versus grafts without barbs and hooks). Patients with bad anatomic preconditions showed a higher complication rate. CONCLUSION: Contrary to first generation products, new stent-graft designs show acceptable technical and clinical results in endovascular AAA aneurysm repair. However, this therapy still should be reserved only for patients with significant comorbities and suitable anatomic conditions.

Midterm outcome of endovascular abdominal aortic aneurysm repair in octogenarians: a single institution's experience.

OBJECTIVES: We analyzed midterm durability of endovascular abdominal aortic aneurysm repair (EVAR) in octogenarians compared with younger patients. METHODS: Data for 182 consecutive patients who underwent elective EVAR between 1999 and 2003 were retrospectively reviewed. Forty-nine patients (27%) were 80 years or older (study group [SG]; mean age, 84 years; range, 80-89 years), and 133 patients (73%) were younger (control group [CG]; mean age, 72 years; range, 53-79 years). Chi2 analysis, Fisher exact test, Student t test, and Mann-Whitney U test were used as appropriate to test for intergroup differences. Kaplan-Meier curves, log-rank tests, and multivariate Cox models were used for time-to-event analysis, with P < or =.05 considered significant. RESULTS: Mean follow-up was 16 months (range, 1-43 months). Body weight was higher (P <.001), and elevated plasma lipid levels (59% vs 43%; P =.042) and use of nicotine (47% vs 29%; P =.015) more frequent in the octogenarians. Baseline aneurysm size, procedure-related data, and hospital stay were comparable between groups. Aneurysm-related mortality was 0% in the study group and 0.7% in the control group (P =.740). Systemic complications occurred in 22% (SG) versus 11% (CG) (P =.035), owing to a rise in serum creatinine concentration greater than 30% of baseline in 14% in the octogenarian group (vs 5% in the CG; P =.048). Groin lymphoceles developed in 12% (SG) versus 2% (CG; P =.013). Technical success was 96% (SG) versus 98% (CG; P =.408), and clinical success was 86% versus 90% (P =.269). No aneurysm rupture occurred during follow-up, and aneurysm-related adverse events were comparable between groups. The estimated risk for any type of endoleak (2.2; 95% confidence interval [CI], 1.1-4.2; P =.023) or type II endoleak (2.1; 95% CI, 1.0-4.3; P = 0.51) was higher in the study group versus the control group; however, this did not affect secondary procedure rates (SG 16% vs CG 12%; estimated risk, SG vs CG,: 1.5; 95% CI, 0.6-3.6; P = 0.420) or aneurysm remodeling (97.2% combined aneurysm sac stabilization or decrease in both groups; P =.592). Aneurysm enlargement occurred in 2.8% (SG 1 vs CG 4; P =.592). CONCLUSION: Elective EVAR in octogenarians appears safe and effective over midterm follow-up, with a temporary decrease in renal function (14%) and postoperative lymphoceles (12%) being the most common postoperative adverse events. Advanced chronologic age is not associated with diminished procedural outcome, clinical success, or postoperative survival, compared with younger age. Because of low perioperative mortality and high procedural success, EVAR may be the preferred approach to abdominal aortic aneurysm treatment in selected elderly patients.

Mid-term results after endovascular repair of the atherosclerotic descending thoracic aortic aneurysm.

INTRODUCTION: Thoracic aortic aneurysms (TAA) are the most common condition of the thoracic aorta requiring surgical treatment. Despite significant improvement in anesthetic, surgical techniques and postoperative care, the mortality and morbidity rate in TAA-repair remains high. The aim of this study was to assess the morbidity and mortality rate after endovascular stent-graft treatment of atherosclerotic (non-dissecting) TAAs. METHODS: Thirty-one patients, ASA-classification III-IV, with symptomatic or expanding atherosclerotic TAAs underwent endovascular stent-graft repair between May 1997 and August 2003. Procedures were performed on an emergency basis in 13 patients and elective in 18 patients. Patients were assessed postoperatively by routine CT-scan within 48 h. Further follow up investigations were performed after 3, 6, 12 months and annually thereafter. RESULTS: Stent-graft placement was successful in all but one patient in whom the stent-graft procedure had to be postponed due severe hemodynamic instability. Perioperative mortality rate was 19% including three haemorrhages, two cardiac events and one respiratory failure (6/31). Technical success rate was 55% (17/31). Completion CT scans performed in 30 patients within 2 days of stent-graft procedure showed type I leaks in seven patients (23%), type II leaks in four patients (13%) and type III leaks in two patients (6%). Further complications included one stroke, one paralysis, one spinalis anterior syndrome and five relevant access related complications. New onset endoleaks, all type I, were observed in seven patients (23%) occurring after 3, 4, 7, 8, 17, 25 and 26 months. Mean follow-up was 15 months (range 2-69 months). CONCLUSION: Thoracic aortic atherosclerotic aneurysm stent-grafting is feasible but not without significant morbidity and mortality.

Neuropathic pain after femoropopliteal bypass surgery.

OBJECTIVE: This retrospective study was performed to investigate prolonged postoperative pain in the area of the proximal or distal scar or the bypass tunnel after femoropopliteal bypass surgery to treat symptomatic peripheral arterial disease. PATIENTS AND METHODS: Ninety-three patients with peripheral arterial disease who underwent femoropopliteal bypass surgery between January 2000 and December 2002 were included in the study. The short-form McGill Pain Questionnaire was used to score pain. Ultrasound examination of the soft tissue around the graft was performed to exclude other pathologic conditions responsible for pain, such as inflammatory processes, perigraft reactions, swollen lymph nodes, and hematomas. RESULTS: Pain in at least one scar existed in 22 patients on average 13.9 +/- 9.8 months after surgery. In 10 patients pain existed simultaneously along the inguinal scar and the above-knee or below-knee scar. Pain along the bypass tunnel was experienced by seven patients. Most patients had mild to moderate pain. The mean numeric ranking score of pain severity in patients with pain was 4.2 +/- 2.3. The occurrence of prolonged postoperative pain was not associated with age, gender, diabetes, indication for surgery, material or type of bypass, number of preceding operations, or postoperative wound complications. Only follow-up time after femoropopliteal bypass surgery tended to be lower in patients with pain compared with those without pain. CONCLUSION: Prolonged postoperative neuropathic pain along the distal and proximal incision or the bypass tunnel exists in one fourth of patients after femoropopliteal bypass surgery. Patients should be informed of this kind of complication before surgery. The results of our study justify further investigations of the origin and treatment of this pain, to find effective methods to reduce the incidence of prolonged postoperative pain after femoropopliteal bypass surgery.

Stent-graft repair for acute traumatic thoracic aortic rupture.

Traumatic rupture of the thoracic aorta is potentially life-threatening and leads to death in 75 to 90 per cent of cases at the time of injury. In high-risk patients, as traumatic injuries of the aorta combine with multiple associated injuries, endoluminal repair is now reported as a promising therapeutic strategy with encouraging results. This study determined the outcome of patients with traumatic thoracic aortic injury treated endovascularly during the past 7 years at our institution. Thirteen patients, 11 males and 2 females (mean age, 39 years; range, 19-82), with traumatic rupture of the otherwise unremarkable descending aorta (10 acute, 3 chronic), out of a series of 64 endovascular thoracic stent-graft procedures, were treated by implantation of Talent (n = 8), Vanguard (n = 5), and Excluder (n = 2) self-expanding devices between January 1996 and August 2003. The immediate technical success rate was 92 per cent (12/13). One patient showed a proximal endoleak type I, which was treated successfully by an additional stent-graft procedure. Secondary success rate was 100 per cent. The mortality rate was 0 per cent. Two additional stent-graft procedures were performed due to type I endoleaks after 18 and 28 months. There was no other intervention-related morbidity or mortality during the mean follow-up time of 26.4 months' (range, 6-86). Endovascular stent-graft repair of traumatic thoracic aortic injuries is a safe, effective, and low-morbidity alternative to open thoracic surgery and has promising midterm results.

Far field potentials from the brain stem after transcutaneous vagus nerve stimulation.

Recently, the vagus nerve has gained particular interest in neuropsychiatry, as neurodegenerative diseases like Alzheimer's and Parkinson's disease are supposed to affect the brainstem nuclei of the vagus nerve early in their course. In addition, electric stimulation of the vagus nerve has therapeutic effects in otherwise therapy-refractory epilepsies and depressions. So far, no method is available to assess vagus nerve function in this context. On this background and based on the established techniques of early acoustic evoked potentials we investigated if a transcutaneous electric stimulation of the sensory auricular branch of the vagus nerve innervating parts of the outer ear is feasible in healthy subjects using this hypothesis-generated approach. We were able to record a clear, reproducible Vagus Sensory Evoked Potential (VSEP) measured as far field potential probably originating in vagus nuclei in the brainstem. Further studies are needed to test the interindividual stability and test-retest reliability of this new method before potential diagnostic and therapeutic applications might be evaluated.

Kissing stents for treatment of complex aortoiliac disease.

OBJECTIVES: to determine medium term technical and clinical success of kissing stents for aortoiliac occlusive disease. DESIGN: retrospective study. SUBJECTS: twenty-five patients presenting with intermittent claudication (IC) or critical limb ischaemia (CLI) due to aortoiliac disease (41 complex stenoses, 8 occlusions). METHODS: balloon- or self-expanding kissing stents, with or without predilatation depending upon the nature of the disease, were inserted via bilateral retrograde femoral artery punctures. Clinical examination, ABPI, exercise testing and duplex ultrasound were performed at 1, 3, 6, and 12 months, and then annually. RESULTS: technical success was achieved in 86% segments. All patients with CLI improved and 6 of 7 ulcerated limbs showed complete healing. During follow-up, 7 patients died and two patients required major amputation at 7 and 8 months. The primary assisted patency rate was 94, 91 and 65% at 6, 12, and 24 months, respectively. CONCLUSIONS: despite acceptable short-term technical and clinical success, as the medium term patency rates are clearly inferior to those of bypass surgery, the kissing stent technique should be reserved for high risk patients with a limited life expectancy.

[Treatment strategies for gastroesophageal reflux disease]. / Strategien zur Behandlung der gastroösophagealen Refluxkrankheit.

Gastroesophageal reflux disease (GERD) is a very common disorder. Therapeutic options include lifestyle modifications, medical therapy, laparoscopic antireflux surgery, and three more recent options-injection therapy to the lower esophageal sphincter, endoscopic sewing procedures, and radio frequency ablation therapy. Medical therapy is effective in most patients but not always successful with advanced disease. Up to 70% of subjects do not have adequate nocturnal control of gastric acid secretion with 20 mg of omeprazole given twice per day. Patients who do not tolerate medical therapy, who respond inadequately, or who want to avoid life-long drug therapy are candidates for alternate treatments. Studies on endoscopic procedures such as polymethylmethacrylate (PMMA) injection, the Stretta procedure,and endoscopic suturing techniques all suffer from having small study groups for each procedure,unknown durability, short follow-up, and the absence of randomized, controlled procedures. Limitations on endoscopic techniques are esophageal motility disorders, severe esophagitis, and larger hiatal hernias. Laparoscopic antireflux surgery remains a well-established, durable alternative to long-term medical therapy. It has the benefits of convenience, safety, minimal complications, improved quality of life, and low cost. Alternative methods will have to earn their place against this gold standard.

Traumatic pseudoaneurysm of the brachiocephalic artery following medianoscopy: initial endovascular repair followed by open surgery--a case report.

Endovascular stent graft repair of traumatic vessel injuries is gaining worldwide acceptance as a minimally invasive alternative to open surgical repair. However, effective endovascular repair fails if the aneurysm is not completely excluded. Conversion to open surgery may be unavoidable in such cases. Herein we describe the case of a 45-year-old man who was referred to our hospital with a pseudoaneurysm of the proximal brachiocephalic artery caused by biopsy during diagnostic medianoscopy. The pseudoaneurysm was primarily treated by stent-graft implantation into the proximal brachiocephalic artery. As a result of the unfavorable location of the lesion exclusion of the aneurysm failed and the initial therapy had to be extended to open reconstruction of the brachiocephalic artery. A bypass procedure from the aortic arch to the right common carotid artery was performed with reinsertion of the right subclavian artery to exclude the pseudoaneurysm.

Clinical and objective data on spinal cord stimulation for the treatment of severe Raynaud's phenomenon.

Ischemic vascular disease of the upper extremity represents a difficult therapeutic problem wherein medical treatment often fails. Epidural spinal cord stimulation has been shown to be an effective alternative in severe peripheral arterial disease. Although this method has been used for nearly two decades only limited experience exists in Raynaud's phenomenon of the upper limbs. In addition objective parameters to prove therapeutic success are not well defined. Herein we describe a patient with severe primary Raynaud's phenomenon over several years who had significant pain relief and complete healing of ischemic digital ulcerations after spinal cord stimulation. Pain level was evaluated using a visual rating scale before and after surgery. Microcirculatory parameters were assessed before and after spinal cord stimulation by capillary microscopy and laser Doppler anemometry. Significant improvement of red blood cell velocity, capillary density, and capillary permeability was demonstrated. At follow-up 18 months after surgery the patient had no complaints and all ulcerations of her fingertips had healed. Spinal cord stimulation appears to be an effective treatment in severe cases of Raynaud's phenomenon and we recommend its use in the case of failed medical therapy. Pain rating and capillary microscopy enable one to assess and visualize the effects of spinal cord stimulation.

[Effectiveness of locoregional rt-PA lysis in acute leg and arm vein thrombosis]. / Wirksamkeit der loko-regionalen rt-PA-Lyse bei Bein- bzw. Armvenenthrombose.

39 patients suffering from a thrombosis of the peripheral venous system were treated with a loco-regional lysis, using rt-PA. Two cycles of 40 mg rt-PA a day were applicated by means of a special drainage-management, using perforans veins. During lytic therapy, 20,000 to 30,000 IE of unfractionized heparin were additionally administered. Laboratory work including aPTT and fibrinogen measurement was performed every 8 hours. Additionally a phlebography was performed after 24 hours. Patients received an anticoagulative therapy using sintrom or marcumar the following 3 months. We obtained a successful thrombolysis without any major complications in 90%. Minor complications included 3 peripheral pulmonary embolisms. Duplex sonographic and plethysmographic follow up was performed in 25 patients one year after operation. In two patients with ankle edema insufficient valves at the popliteal vein were found with both diagnostic modalities. 23 patients showed no signs of insufficient valves neither clinically nor at duplex sonography and plethysmography. The locoregional lysis appears to be an effective method for the treatment of acute peripheral vein thrombosis.

Ruptured false abdominal aortic aneurysm during pregnancy: Caesarean delivery followed by aortic reconstruction.

We describe a case of a successfully treated ruptured abdominal aortic aneurysm during pregnancy. The importance of close clinical follow-up after any aortic reconstructions is highlighted.

Test-retest reliability of electrophysiological parameters related to cognitive motor control.

Previously, the continuous performance test was demonstrated to elicit distinct electrophysiological correlates of cognitive response during execution (Go) and inhibition (NoGo) of an anticipated motor response. A robust method for topographical quantification of these brain electrical microstates has been established recently. Test reliability is crucial to allow application in the assessment of neuropsychiatric disorders. The present study evaluates the reliability of the Go and NoGo centroid locations as well as the NoGo anteriorisation (NGA) in 23 healthy individuals. Our results show supreme test-alternate retest reliabilities of Pearson's product moment correlations and intraclass correlation coefficients of r> or =0.63 (P< or =0.001) for these parameters which assert a quality well within the range reported for those of other electrophysiological standard paradigms. Go and NoGo centroid locations as well as the NGA are, therefore, reliable correlates of prefrontal motor control and may contribute to the understanding of disorders with allied impairments.

Nipple complication caused by a mesenteric GORE-TEX sling reinforcement in a Kock ileal reservoir: report of a case.

INTRODUCTION: The surgical trend after proctocolectomy at present is to perform a pelvic pouch reservoir with an ileoanal anastomosis. Before that a continent ileal Kock pouch was the procedure of choice, which enabled the patient to collect the intestinal discharge for several hours and avoid involuntary escape of reservoir contents, thus making the wearing of plastic bags unnecessary. Although in the majority of patients an increased life quality can be observed, different complications with a Kock pouch may occur. METHODS: We present a case of a young female with signs of outlet obstruction several years after a Kock reservoir was performed because of complicated ulcerative colitis. The obstruction was caused by a fecal-coated GORE-TEX sling that had penetrated through the nipple-valve base into the pouch. The mesenteric sling was introduced as a modification of the original Kock procedure to reinforce the efferent ileal segment, thus preventing nipple prolapse. The perforation site was closed with interrupted sutures and an ileostomy was performed. RESULTS: Three months thereafter, the ileostomy was closed and at a follow-up visit one year later the patient had no complaints and a well-functioning reservoir. CONCLUSION: If continence is desired after definitive ileostomy or if failure of the ileoanal reservoir occurs, a Kock pouch procedure still has a place in the surgical armamentarium of colorectal surgery. Many experts today do not use sling reinforcement maneuvers, and most of these procedures seem to work well without it.

Laparoscopic reoperation after failed antireflux surgery.

INTRODUCTION: Laparoscopic surgery for the treatment of gastroesophageal reflux disease has been established as being safe, effective, and the best alternative to continuous life-long medical therapy. Antireflux surgery is not, however, devoid of complications and failures. Treatment of these patients represents a major challenge, especially when reoperation is indicated. PATIENTS: One-hundred consecutive patients had a reoperation in our clinic. Previous antireflux procedures were laparoscopic (52 patients), laparotomy (39 patients), and thoracotomy (9 patients). RESULTS: Peri- or postoperative complications occurred in 30 patients (30%). Operative complications were stomach perforation (14), significant bleeding (6), esophageal mucosal perforation (4), gastrocutaneous fistula (2), small bowel enterotomy followed by fistula (1), and tension pneumothorax (1). Reoperation was required in only 2 patients because of a missed stomach perforation or persistent chest leak. The conversion rate (from laparoscopic to open procedure) was 17% overall. CONCLUSION: Laparoscopic reoperation after a failed antireflux procedure is a major surgical challenge, and it is not devoid of morbidity. The surgeon must have extensive experience in laparoscopic surgery and should be able to perform reoperative open surgery through the abdomen and chest. Laparoscopic redo surgery is feasible with good results. Many patients in whom previous open surgery has failed enjoy the advantages of a laparoscopic redo procedure.

Exclusion limits on the WIMP-nucleon cross section from the cryogenic dark matter search.

The Cryogenic Dark Matter Search (CDMS) employs Ge and Si detectors to search for weakly interacting massive particles (WIMPs) via their elastic-scattering interactions with nuclei while discriminating against interactions of background particles. CDMS data, accounting for the neutron background, give limits on the spin-independent WIMP-nucleon elastic-scattering cross section that exclude unexplored parameter space above 10 GeV/c2 WIMP mass and, at >75% C.L., the entire 3sigma allowed region for the WIMP signal reported by the DAMA experiment.

Stability of late event-related potentials: topographical descriptors of motor control compared with the P300 amplitude.

The P300-amplitude evoked with an acoustic oddball-paradigm is considered the most stable late event-related potential (ERP). This amplitude-index has become a standard parameter in electrophysiology. Recently, a robust ERP-parameter (NoGo-anteriorization, NGA) has been introduced, which reflects spatial brain electrical changes in relation to execution and inhibition of a motor response elicited with a Continuous Performance Test (CPT). The current study refers to the stability of this new topographical ERP-parameter compared to the stability of the classical P300-amplitude. For that purpose, 12 healthy subjects were investigated with both paradigms during recording of a 21-channel EEG. Analysis of the resulting ERPs revealed a very high stability for both, topographical and amplitude index: In every single subject, the brain electrical fields were characterized by a more anterior location in the NoGo- compared to the Go-condition (=NGA) and by higher amplitudes after target compared to distractor condition. T-tests, analyses of the effect size and of the power revealed equivalent differences between the two contrasting conditions for the topographical compared to the amplitude index. These results indicate that the stability of the topographical ERP-parameters elicited with the CPT is sufficient for an electrophysiological standard-index. The possibility to elicit a robust and specific spatial brain activation with the CPT is an ideal completion to the classical P300 amplitude effect and, therefore, hopefully will be a useful expansion of the standard paradigms in electrophysiological laboratories.