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1.
Pain Med ; 15(9): 1575-89, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25234478

RESUMEN

OBJECTIVE: Guidelines for complex regional pain syndrome (CRPS) 1 advocate several substance classes to reduce pain and support physical rehabilitation, but guidance about which agent should be prioritized when designing a therapeutic regimen is not provided. Using a network meta-analytic approach, we examined the efficacy of all agent classes investigated in randomized clinical trials of CRPS 1 and provide a rank order of various substances stratified by length of illness duration. DESIGN: In this study a network meta-analysis was conducted. PATIENTS: The participants of this study were patients with CRPS 1. METHOD: Searches in electronic, previous systematic reviews, conference abstracts, book chapters, and the reference lists of relevant articles were performed. Eligible studies were randomized controlled trials comparing at least one analgesic agent with placebo or with another analgesic and reporting efficacy in reducing pain. Summary efficacy stratified by symptom duration and length of follow-up was computed across all substance classes. Two authors independently extracted data. RESULTS: In total, 16 studies were included in the analysis. Bisphosphonates appear to be the treatment of choice in early stages of CRPS 1. The effects of calcitonin surpass that of bisphosphonates and other substances as a short-term medication in more chronic stages of the illness. While most medications showed some efficacy on short-term follow-up, only bisphosphonates, NMDA analogs, and vasodilators showed better long-term pain reduction than placebo. LIMITATION: For some drug classes, only a few studies were available and many studies included a small group of patients. Insufficient data were available to analyze efficacy on disability. CONCLUSION: This network meta-analysis indicates that a rational pharmacological treatment strategy of pain management should consider bisphosphonates in early CRPS 1 and a short-term course of calcitonin in later stages. While most medications showed some efficacy on short-term follow-up, only bisphosphonates, NMDA analogs and vasodilators showed better long-term pain reduction than placebo.


Asunto(s)
Analgésicos/uso terapéutico , Manejo del Dolor , Distrofia Simpática Refleja/tratamiento farmacológico , Corticoesteroides/uso terapéutico , Anciano , Aminas/uso terapéutico , Analgésicos/clasificación , Ácidos Ciclohexanocarboxílicos/uso terapéutico , Difosfonatos/uso terapéutico , Utilización de Medicamentos/estadística & datos numéricos , Estudios de Seguimiento , Gabapentina , Humanos , Ketamina/uso terapéutico , Persona de Mediana Edad , N-Metilaspartato/agonistas , Guías de Práctica Clínica como Asunto , Ensayos Clínicos Controlados Aleatorios como Asunto/estadística & datos numéricos , Resultado del Tratamiento , Vasodilatadores/uso terapéutico , Ácido gamma-Aminobutírico/uso terapéutico
2.
Pain Pract ; 13(8): 621-6, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23301539

RESUMEN

BACKGROUND: Pain is a major problem for chronic pancreatitis (CP) patients. Unfortunately, medical therapy often fails. Endoscopic and surgical treatments are invasive, and results vary. Percutaneous radiofrequency ablation of the splanchnic nerves (RFSN) is a relatively new and minimally invasive procedure for treatment of intractable pain in CP patients. MATERIALS AND METHODS: We retrospectively evaluated 18 RFSN procedures in 11 CP patients, all refractory to analgesics. Five patients underwent a second procedure; two patients underwent a third procedure. NRS pain scores were assessed. Complications, analgesics usage, and length of the pain-free period were recorded. RESULTS: Radiofrequency ablation of the splanchnic nerves was effective in 15/18 interventions. The mean NRS pain score decreased from 7.7 ± 1.0 to 2.8 ± 2.7 (P ≤ 0.001). The pain-free period lasted for a median period of 45 weeks. The effect of repeated interventions was comparable to the initial procedure. One transient side effect was reported. Four patients reported significantly reduced analgesic usage; 4 patients completely stopped their pain medication. CONCLUSION: Radiofrequency ablation of the splanchnic nerves is a minimally invasive, effective procedure for pain relief. After the effect has subsided, RFSN can be successfully repeated. RFSN might become an alternative treatment in a selected group of CP patients. A larger, randomized trial is justified to substantiate these findings.


Asunto(s)
Ablación por Catéter/métodos , Dolor Intratable/etiología , Dolor Intratable/cirugía , Pancreatitis Crónica/complicaciones , Nervios Esplácnicos/cirugía , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Manejo del Dolor/métodos , Pancreatitis Crónica/cirugía , Estudios Retrospectivos
3.
Fam Pract ; 29(6): 659-70, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22516128

RESUMEN

BACKGROUND: The efficacies and adverse effects of different antibiotics for uncomplicated urinary tract infections (UTIs) have been studied by standard meta-analytic methods using pairwise direct comparisons of antimicrobial treatments: the effects of one treatment are compared to those of either another treatment or placebo. However, for clinical decisions, we need to know the effectiveness of each possible treatment in comparison with all relevant alternatives, not with just one. OBJECTIVES: To compare the efficacies and adverse effects of all relevant antibiotics for UTI treatment simultaneously by performing a network meta-analysis using direct and indirect treatment comparisons. METHODS: Using logistic regression analysis, we performed a network meta-analysis of randomized controlled trials (RCTs) published after 1999 that compared different oral antibiotic or placebo regimens for UTI treatment in general practice or outpatient settings. We looked at five binary outcomes: early clinical, early bacteriological, late clinical and late bacteriological outcomes, as well as adverse effects. Consequently, a ranking of the antibiotic regimens could be composed. RESULTS: Using a network structure, we could compare and rank nine treatments from 10 studies. Overall, ciprofloxacin and gatifloxacin appeared the most effective treatments, and amoxicillin-clavulanate appeared the least effective treatment. In terms of adverse effects, there were no significant differences. DISCUSSION: Network meta-analysis shows some clear efficacy differences between different antibiotic treatments for UTI in women. It provides a useful tool for clinical decision making in everyday practice. Moreover, the method can be used for meta-analyses of RCTs across primary care and beyond.


Asunto(s)
Antibacterianos/uso terapéutico , Investigación sobre la Eficacia Comparativa , Infecciones Urinarias/tratamiento farmacológico , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Garantía de la Calidad de Atención de Salud , Ensayos Clínicos Controlados Aleatorios como Asunto , Adulto Joven
4.
Eur J Clin Invest ; 40(4): 344-9, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20486996

RESUMEN

BACKGROUND: Vascular calcification in humans is associated with an increased cardiovascular risk. Carboxylated matrix Gla protein (cMGP) inhibits vascular calcification. Vitamin K is an essential cofactor for the activation of uncarboxylated matrix Gla protein (ucMGP). It has been suggested that patients on long-term treatment with vitamin K antagonists develop aortic valve calcifications because of lower levels of circulating MGP. We therefore hypothesized that arterial calcification and a low vitamin K status are associated with ucMGP. To that aim, we measured arterial calcium scores, the osteocalcin ratio (OCR), as a proxy for vitamin K status, and ucMGP. MATERIALS AND METHODS: In 36 hypertensive patients, we determined the Agatston score with computer tomography scans of the abdominal aorta, carotid and coronary arteries. The total calcium score was calculated as the sum of the separate Z-scores. RESULTS: The total calcium Z-score was significantly correlated to age (r = 0.683, P < 0.001), smoking (r = 0.372, P = 0.026), total cholesterol (r = 0.353, P = 0.034), LDL cholesterol (r = 0.490, P = 0.003), triglycerides (r = 0.506, P = 0.002), fasting glucose (r = 0.454, P = 0.005), systolic blood pressure (r = 0.363, P = 0.029) and pulse pressure (r = 0.685, P < 0.001). In multivariate regression analyses, OCR and total calcium score were significantly associated with ucMGP. CONCLUSIONS: We found a positive association of total arterial calcium score and a high OCR (reflecting low vitamin K status) with ucMGP serum levels. This warrants further studies to explore the pathophysiological background of this phenomenon.


Asunto(s)
Calcinosis , Proteínas de Unión al Calcio/metabolismo , Calcio/metabolismo , Proteínas de la Matriz Extracelular/metabolismo , Osteocalcina/metabolismo , Vitamina K/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Calcio/sangre , Proteínas de Unión al Calcio/sangre , Cardiomiopatías , Proteínas de la Matriz Extracelular/sangre , Femenino , Humanos , Hipertensión , Masculino , Persona de Mediana Edad , Tomografía Computarizada por Rayos X , Vitamina K/sangre , Proteína Gla de la Matriz
5.
Breast Cancer Res Treat ; 120(2): 499-506, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19418215

RESUMEN

The purpose of the study was to evaluate the impact of a computer-aided detection (CAD) system on the performance of mammogram readers in interpreting digital mammograms in a clinical population. Furthermore, the ability of a CAD system to detect breast cancer in digital mammography was studied in comparison to the performance of radiologists and technologists as mammogram readers. Digital mammograms of 1,048 consecutive patients were evaluated by a radiologist and three technologists. Abnormalities were recorded and an imaging conclusion was given as a BI-RADS score before and after CAD analysis. Pathology results during 12 months follow up were used as a reference standard for breast cancer. Fifty-one malignancies were found in 50 patients. Sensitivity and specificity were computed before and after CAD analysis and provided with 95% CIs. In order to assess the detection rate of malignancies by CAD and the observers, the pathological locations of these 51 breast cancers were matched with the locations of the CAD marks and the mammographic locations that were considered to be suspicious by the observers. For all observers, the sensitivity rates did not change after application of CAD. A mean sensitivity of 92% was found for all technologists and 84% for the radiologist. For two technologists, the specificity decreased (from 84 to 83% and from 77 to 75%). For the radiologist and one technologist, the application of CAD did not have any impact on the specificity rates (95 and 83%, respectively). CAD detected 78% of all malignancies. Five malignancies were indicated by CAD without being noticed as suspicious by the observers. In conclusion, the results show that systematic application of CAD in a clinical patient population failed to improve the overall sensitivity of mammogram interpretation by the readers and was associated with an increase in false-positive results. However, CAD marked five malignancies that were missed by the different readers.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Mamografía , Interpretación de Imagen Radiográfica Asistida por Computador/métodos , Radiología/métodos , Adulto , Anciano , Anciano de 80 o más Años , Reacciones Falso Positivas , Femenino , Personal de Salud/normas , Humanos , Mamografía/métodos , Mamografía/normas , Persona de Mediana Edad , Radiología/normas , Sensibilidad y Especificidad , Programas Informáticos , Adulto Joven
6.
Int J Technol Assess Health Care ; 25(4): 505-13, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19845980

RESUMEN

OBJECTIVES: The aim of this study was to assess the costs and effects of using specialized breast technologists in prereading mammograms to reduce the increasing workload of radiologists in daily clinical practice. Mammography is the most widely used imaging modality for early detection and diagnosis of breast cancer. METHODS: A total of 1389 mammograms of consecutive patients were evaluated by two technologists trained in mammogram interpretation. The costs and effects of four different experimental strategies of prereading mammograms by technologists were analyzed by decision analytic modeling and compared with the conventional strategy of standard evaluation by the radiologist on duty. RESULTS: Overall, the employment of technologists in this patient population resulted in a potential time saving up to 73 percent (1019/1389) for the radiologist. No additional false-negative imaging results were found as compared to the conventional strategy. The total diagnostic costs in the conventional strategy were determined at euro150,602. The experimental strategies resulted in cost savings up to 17.2 percent (range, euro122,494-euro139,781). CONCLUSIONS: The employment of technologists in prereading mammograms in a clinical patient population could be effective to reduce the workload of radiologists without jeopardizing the detection of malignancies. Furthermore, diagnostic costs can be reduced considerably.


Asunto(s)
Técnicos Medios en Salud/economía , Mamografía/economía , Adulto , Anciano , Anciano de 80 o más Años , Análisis Costo-Beneficio , Femenino , Humanos , Persona de Mediana Edad , Estudios Prospectivos
7.
Int J Cancer ; 125(12): 2923-9, 2009 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-19672861

RESUMEN

Mammography is the basic imaging modality for early detection of breast cancer. The aim of this prospective study was to evaluate the impact of different mammogram reading strategies on the diagnostic yield in a consecutive patient population referred for digital mammography to a hospital. First, the effect of using computer-aided detection (CAD) software on the performance of mammogram readers was studied. Furthermore, the impact of employing technologists as either prereaders or double readers was assessed, as compared to the conventional strategy of single reading by a radiologist. Digital mammograms of 1,048 consecutive patients were evaluated by a radiologist and 3 technologists with and without the use of CAD software. ROC analysis was used to study the effects of the different strategies. In the conventional strategy, an overall area under the curve (AUC) of 0.92 was found, corresponding to a sensitivity of 84% and specificity of 94%. When applying CAD software, the AUCs were similar before and after CAD for all readers (mean of 0.95). Employing technologists in prereading and double reading of mammograms resulted in a mean AUC of 0.91 and 0.96, respectively. In the prereading strategy, the corresponding sensitivity and specificity were 81 and 96%; in the double reading strategy they were 96 and 79%, respectively. Concluding, in this clinical population, systematic application of CAD software by either radiologist or technologists failed to improve the diagnostic yield. Furthermore, employing technologists as double readers of mammograms was the most effective strategy in improving breast cancer detection in daily clinical practice.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Mamografía/instrumentación , Mamografía/métodos , Reconocimiento de Normas Patrones Automatizadas/métodos , Interpretación de Imagen Radiográfica Asistida por Computador , Diagnóstico por Computador , Femenino , Humanos , Tamizaje Masivo/métodos , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Curva ROC , Programas Informáticos
8.
J Ren Care ; 35(2): 82-9, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19432853

RESUMEN

BACKGROUND: Little is known about the relationship of cannulation practices in dialysis facilities with the frequency of failed cannulations, complications and subsequent vascular access (VA) failure. METHODS: In an observational study the incidence of mis-cannulations and related complications were observed. Patient characteristics, comorbidities and VA characteristics like type of VA were correlated with occurrence of cannulation-related complications. In addition, the cannulation technique and practice patterns like needle direction, tourniquet use and years of experience of dialysis nurses were registered. RESULTS: During the study period, 37% of patients with autogenous arteriovenous fistulae (AVF), and 19% of patients with arteriovenous grafts (AVG) had more than 10 miscannulations. Cannulation-induced haematoma resulted into single-needle (SN) and catheter dialysis in 40% of the patients. The use of central venous catheters (CVC) and SN dialysis were significant predictors of VA failure (p <0.0001). CONCLUSION: This study demonstrated a high incidence of unsuccessful cannulation procedures and cannulation-related complications necessitating catheter and SN dialysis. The type and location of the VA is significantly related to occurrence of unsuccessful and complicated cannulation.


Asunto(s)
Derivación Arteriovenosa Quirúrgica , Prótesis Vascular , Cateterismo/efectos adversos , Catéteres de Permanencia , Errores Médicos/estadística & datos numéricos , Diálisis Renal , Adulto , Anciano , Anciano de 80 o más Años , Cateterismo/instrumentación , Cateterismo/métodos , Cateterismo/enfermería , Análisis de Falla de Equipo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Países Bajos , Estudios Prospectivos , Análisis de Regresión , Diálisis Renal/enfermería , Factores de Riesgo
9.
Am J Hypertens ; 21(9): 969-75, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18583985

RESUMEN

BACKGROUND: Masked hypertension (MH) is a relatively newly detected condition of which little is known. More information about MH may help to improve overall antihypertensive health care. We aimed to investigate the prevalence, potential causes, and associated consequences of MH. METHODS: We searched published literature using MEDLINE, EMBASE, and the Cochrane database completed with references cited in reviews and original study articles. We restricted our research to articles written in the English, German, French, and Spanish language. Studies were included only when the prevalence of MH was reported, office blood pressure (BP) values were given, and methods of BP measurements were described in detail. All data were extracted independently by two readers with a standardized protocol and data-collection form. RESULTS: The prevalence of MH averaged 16.8% (95% confidence interval 13.0-20.5%). The MH prevalence was 7% for children and 19% for adults. MH prevalences did not differ significantly when determined with self or ambulatory BP measurement (21.1% vs. 16.8%; P = 0.42). Subjects with MH had significantly higher left ventricular mass index (LVMI) values than normotensives (110 vs. 98 g/m2; P < 0.01) but similar values as sustained hypertensives (109 g/m2). In addition, patients with MH were more often smokers than normotensives (mean difference 18%; P < 0.03). CONCLUSIONS: MH strikes about a quarter of the patients who were initially classified as normotensives (based on office BP measurements) and of treated hypertensives. Patients with MH seem to have a similar cardiovascular risk as sustained hypertensives but they may remain undetected. The presence of MH seems to be a matter of a coincidently low office BP value not related to certain subject characteristics although the chance of its presence may be increased by smoking and antihypertensive treatment.


Asunto(s)
Hipertensión/diagnóstico , Adulto , Niño , Humanos , Hipertensión/epidemiología , Hipertensión/etiología , Prevalencia
10.
Eur Radiol ; 18(10): 2076-84, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18431574

RESUMEN

The degree of adherence with evidence-based guidelines for the use of breast ultrasonography was determined in clinical practice of radiologists in six hospitals. Additional ultrasonography was performed in 2,272 (53%) of all 4,257 patients referred for mammography. High adherence rates (mean: 95%) were observed for guidelines recommending ultrasonography in patients referred for palpable breast masses and abnormal screening and diagnostic mammograms. Lower adherence rates (mean: 81%, Pearson correlation coefficient= -0.57; p=0.001) were found for guidelines advising against additional ultrasonography in patients referred for breast symptoms, a known benign abnormality, a family history or anxiety of breast cancer. The overuse of ultrasonography in 442 patients and underuse in 95 patients led to five additional false-positive results. It was concluded that the guidelines seem workable and feasible in clinical practice and that the current daily routine of diagnostic breast imaging corresponded to a great extent to the guidelines proposed.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/epidemiología , Adhesión a Directriz/estadística & datos numéricos , Guías de Práctica Clínica como Asunto , Pautas de la Práctica en Medicina/normas , Ultrasonografía Mamaria/estadística & datos numéricos , Ultrasonografía Mamaria/normas , Femenino , Humanos , Persona de Mediana Edad , Reproducibilidad de los Resultados , Medición de Riesgo/métodos , Medición de Riesgo/normas , Factores de Riesgo , Sensibilidad y Especificidad
11.
NMR Biomed ; 20(8): 717-25, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17295393

RESUMEN

To assess the use of MRI for evaluating changes in muscle blood flow and number of collateral arteries, serial dynamic contrast-enhanced MRI (DCE-MRI) was combined with high-spatial-resolution contrast-enhanced MR angiography (MRA) in a peripheral ischemia model. The combined MRI (DCE-MRI and MRA) protocol was performed serially in 15 male rabbits at 2 h (day 0(+)), 7 days, and 21 days after femoral artery ligation. In the anterior tibial and soleus muscle, changes in resting muscle blood flow determined as the endothelial transfer coefficient (K(trans)) and arterial inflow delay from DCE-MRI and changes in the number of sub-millimeter sized collateral arteries as scored with MRA were measured. Directly after ligation, K(trans) in the anterior tibial muscle was reduced to 23% of that in the control limb, then recovered to 81% on day 7, and to 85 % on day 21. K(trans) in the soleus muscle recovered from a reduction to 63% on day 0(+), to 85% on day 7, and to 90% on day 21. The number of collaterals around the ligated femoral artery increased from 1.1 on day 0(+) to 4.2 on day 7, and 6.0 on day 21 in the ligated limb only. Combined DCE-MRI and MRA allows non-invasive serial monitoring of changes in muscle blood flow and growth of sub-millimeter sized collateral arteries in a rabbit femoral artery ligation model.


Asunto(s)
Circulación Colateral/fisiología , Arteria Femoral/anatomía & histología , Angiografía por Resonancia Magnética/métodos , Animales , Miembro Posterior/inervación , Cinética , Imagen por Resonancia Magnética/métodos , Modelos Animales , Conejos
12.
J Vasc Surg ; 45(1): 71-7; discussion 77-8, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17210385

RESUMEN

OBJECTIVE: Preoperative knowledge of the blood-supplying trajectory to the spinal cord is of interest, because spinal cord ischemia may occur during thoracic aortic aneurysm (TAA) and thoracoabdominal aortic aneurysm (TAAA) repair and possibly leads to paraplegia. The Adamkiewicz artery (AKA) is considered to be the most important blood supplier of the thoracolumbar spinal cord and has therefore been the focus in preoperative diagnostic imaging. However, in TAA(A) patients, the blood supply to the spinal cord may strongly depend on (intersegmental) collateral circulation, because many segmental arteries are occluded as a result of atherosclerosis. Therefore, the importance of preserving the segmental artery supplying the AKA (SA-AKA) is debated. Here it was investigated whether (1) the AKA and its segmental supplier can be imaged by using magnetic resonance (MR) angiography and (2) aortic cross-clamping of the SA-AKA influences intraoperative spinal cord function, monitored by motor evoked potentials (MEPs). METHODS: Preoperative MR angiography was performed to localize the SA-AKA and the AKA in 60 patients (19 TAA, 7 TAAA I, 18 TAAA II, 9 TAAA III, and 7 TAAA IV). Spinal cord function was monitored during surgery by using MEPs. When MEPs indicated critical ischemia, the SA-AKA was selectively reattached. To test whether aortic cross-clamping of the SA-AKA was associated with MEP decline, the Fisher statistical exactness test was applied. RESULTS: The AKA and SA-AKA could be localized in all 60 (100%) patients between vertebral levels T8 and L2 (72% left sided). In 44 (73%) patients, the SA-AKA was cross-clamped, which led in 32% (14/44) of cases to MEP decline. Reattachment of the preoperatively localized SA-AKA re-established MEPs and, thus, spinal cord function in 12 of 14 cases. When the SA-AKA was outside the area cross-clamped, the MEPs always remained stable. A significant association (P < .01) was found between the location of the SA-AKA relative to the aortic cross-clamps and the MEPs. CONCLUSIONS: The AKA can be localized before surgery in 100% of TAA(A) patients by using MR angiography. Location of the SA-AKA outside the cross-clamped aortic area is attended with stable MEPs. Interestingly, it was found that in most patients in whom the SA-AKA was cross-clamped, MEPs were not affected, thus indicating sufficient collateral blood supply to maintain spinal cord integrity. Nevertheless, preoperative knowledge of SA-AKA location is of importance, because in 32% of patients, spinal cord function was dependent on this supplier. Revascularization of the SA-AKA can thereby reverse spinal cord dysfunction.


Asunto(s)
Aneurisma de la Aorta Abdominal/diagnóstico , Aneurisma de la Aorta Torácica/diagnóstico , Potenciales Evocados Motores/fisiología , Angiografía por Resonancia Magnética , Médula Espinal/irrigación sanguínea , Anciano , Aneurisma de la Aorta Abdominal/fisiopatología , Aneurisma de la Aorta Abdominal/cirugía , Aneurisma de la Aorta Torácica/fisiopatología , Aneurisma de la Aorta Torácica/cirugía , Femenino , Estudios de Seguimiento , Humanos , Masculino , Monitoreo Fisiológico/métodos , Cuidados Preoperatorios/métodos , Pronóstico , Estudios Retrospectivos , Procedimientos Quirúrgicos Vasculares
13.
J Biomech ; 38(12): 2423-30, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16214490

RESUMEN

The damping mechanisms that are operational in the heel pad during the impact phase of locomotion have the important function to protect the musculo-skeletal system from injuries. How this is achieved is still not fully understood, as is for instance illustrated by the 'heel pad paradox', the observation that in vivo and in vitro experiments yielded widely different results. This paradox could so far only partially be explained. In the light of this paradox, and a previous study by our group, we conjectured that the venous plexus might contribute as a hydraulic shock absorber to the damping properties of the heel pad. To investigate this hypothesis in vivo, heel pads of 11 volunteers were subjected to pendulum impact tests, using velocities of 0.2, 0.4, and 0.6 m/s, and three physiologically different, consecutive conditions: (i) a relatively empty venous plexus, (ii) a congested venous plexus, and (iii) a decongested venous plexus. At congestion, the maximum impact force decreased slightly but significantly by 2.6% at 0.2 m/s and 1.8% at 0.4 m/s. This effect was no longer found at 0.6 m/s. Although these effects are rather small, they confirm the fundamental hypothesis that the venous plexus contributes to the damping properties of the heel pad during walking. It is likely that some underestimation of the effect has occurred.


Asunto(s)
Aceleración , Talón/irrigación sanguínea , Talón/fisiología , Venas/fisiología , Adulto , Elasticidad , Transferencia de Energía/fisiología , Pie/irrigación sanguínea , Pie/fisiología , Humanos , Masculino , Persona de Mediana Edad , Estimulación Física/métodos , Estrés Mecánico , Viscosidad , Caminata
14.
J Am Podiatr Med Assoc ; 95(4): 370-5, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16037553

RESUMEN

We systematically investigated the effect of tube angulation on angular distortion of the anteroposterior radiograph of the foot. Three-dimensional data from the metatarsals originating from computed tomographic scans of ten healthy volunteers were projected onto the supporting surface at various tube angulations to simulate radiography. The distortion of the intermetatarsal angles decreased from 1.2 degrees to 3.5 degrees at 20 degrees tube angulation to 0.4 degrees to 2.7 degrees at 0 degrees tube angulation. The relatively small improvement in angular measurement using 0 degrees instead of 15 degrees tube angulation would not outweigh the adverse effects of changing the standard radiographic technique. Physician awareness of this source of error when planning surgical therapy seems more important.


Asunto(s)
Antepié Humano/diagnóstico por imagen , Huesos Metatarsianos/diagnóstico por imagen , Adulto , Errores Diagnósticos , Femenino , Humanos , Masculino , Huesos Metatarsianos/anatomía & histología , Persona de Mediana Edad , Radiografía/métodos , Radiografía/normas
15.
Foot Ankle Int ; 26(5): 387-93, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-15913524

RESUMEN

BACKGROUND: The measurements on radiographs of the foot are believed to give an objective impression of foot deformities. In patient management, the outcome of these measurements is one of the factors that the physician takes into consideration. In fact, the radiograph is a projection of three-dimensional structures and is as such liable to a certain amount of distortion. To our knowledge this distortion has not been quantified, although it seems important for the interpretation of the measurements. METHODS: First, mathematical models based on the geometry of standard anteroposterior and lateral radiographs were constructed and analyzed. Then, we simulated radiography with these models on three-dimensional data of metatarsals originating from CT scans of 10 normal volunteers. RESULTS: The distortion of the declination angles of the metatarsals was practically negligible. The intermetatarsal angles were distorted up to 5.4 degrees. The measured angles underestimated the three-dimensional angles. CONCLUSIONS: In interpreting the measurements of the metatarsal declination angles, distortion was not a factor. For intermetatarsal angles variability of distortion was only about one third of the reported interobserver variability, but it may have cumulative effects on the error of measured intermetatarsal angles. Moreover, the theoretical models predicted larger distortions in patients with deformities. In interpretation of angular measurements the physician should be aware of these pitfalls.


Asunto(s)
Antepié Humano/diagnóstico por imagen , Huesos Metatarsianos/diagnóstico por imagen , Adulto , Simulación por Computador , Errores Diagnósticos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Radiografía
16.
Radiology ; 235(2): 699-708, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-15858107

RESUMEN

PURPOSE: To prospectively compare the diagnostic accuracies of color duplex ultrasonography (US) and contrast material-enhanced magnetic resonance (MR) angiography and to assess interobserver agreement regarding contrast-enhanced MR angiographic findings in patients suspected of having peripheral arterial disease (PAD). MATERIALS AND METHODS: The institutional review board approved the study, and all patients provided signed informed consent. Two hundred ninety-five patients referred for diagnostic and preinterventional work-up of PAD with duplex US also underwent gadolinium-enhanced MR angiography. Data sets were reviewed for presence or absence of 50% or greater luminal reduction, which indicated hemodynamically significant stenosis, and to determine interobserver agreement. At duplex US, a peak systolic velocity ratio of 2.5 or greater indicated significant stenosis. Primary outcome measures were differences between duplex US and contrast-enhanced MR angiography in sensitivity and specificity for detection of significant stenosis, as assessed with the McNemar test, and interobserver agreement between the two contrast-enhanced MR angiogram readings, expressed as quadratic weighted kappa values. Intraarterial digital subtraction angiography (DSA) was the reference standard. RESULTS: Two hundred forty-nine patients had at least one hemodynamically significant stenotic lesion at contrast-enhanced MR angiography, duplex US, or both examinations. One hundred fifty-two patients underwent intraarterial DSA. The quadratic weighted kappa for agreement regarding the presence of 50% or greater stenosis at contrast-enhanced MR angiography was 0.89 (95% confidence interval [CI]: 0.87, 0.91). Sensitivity of duplex US was 76% (95% CI: 69%, 82%); specificity, 93% (95% CI: 91%, 95%); and accuracy, 89%. Sensitivity and specificity of contrast-enhanced MR angiography were 84% (95% CI: 78%, 89%) and 97% (95% CI: 95%, 98%), respectively; accuracy was 94%. Sensitivity (P = .002) and specificity (P = .03) of contrast-enhanced MR angiography were significantly higher. CONCLUSION: Results of this prospective comparison between contrast-enhanced MR angiography and duplex US provide evidence that contrast-enhanced MR angiography is more sensitive and specific for diagnosis and preinterventional work-up of PAD.


Asunto(s)
Arteriopatías Oclusivas/diagnóstico , Procesamiento de Imagen Asistido por Computador , Claudicación Intermitente/diagnóstico , Angiografía por Resonancia Magnética , Ultrasonografía Doppler en Color , Adulto , Anciano , Anciano de 80 o más Años , Angiografía de Substracción Digital , Medios de Contraste/administración & dosificación , Humanos , Persona de Mediana Edad , Estudios Prospectivos , Valores de Referencia , Sensibilidad y Especificidad
17.
Foot Ankle Int ; 26(12): 1049-54, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16390638

RESUMEN

BACKGROUND: Based on earlier observations that the forefoot bears the highest plantar pressure at its center, the existence of a functional distal transverse arch in normal feet was denied, and plantar pressure was defined as merely the outcome of loading, surface area, and soft tissue. Although plantar pressure drives the changes in the foot, neither the position nor the behavior of the metatarsals during loading can be derived from plantar pressure alone. In light of this, our goal was to describe the changes in thickness in the sole and the corresponding plantar pressure during loading of the foot. METHODS: We used CT to image the foot of 10 subjects in four postures that were chosen to imitate four phases in the walking cycle. Before imaging we also recorded the plantar pressure with a pressure measuring insole on which the subjects were standing. From the data, the minimal thickness of the sole and the corresponding plantar pressure were derived. RESULTS: With the exception of the sesamoids, the thickness of the sole under the bones of the forefoot increased from lateral to medial. This persisted in all postures. Our pressure readings matched previously reported distributions. CONCLUSIONS: Depending on the point of view concerning the sesamoids, the bony prominences were placed in a geometrical arch; but they did not form a functional arch. The soft tissue underneath the heads kept the metatarsals in place; the soft-tissue thickness reflected the principle of adequate cushioning.


Asunto(s)
Antepié Humano/fisiología , Presión , Caminata/fisiología , Adulto , Femenino , Antepié Humano/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Postura/fisiología , Estrés Mecánico , Tomografía Computarizada Espiral
18.
Invest Radiol ; 39(7): 435-44, 2004 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15194915

RESUMEN

RATIONALE AND OBJECTIVES: To compare the ability of intra-arterial digital subtraction angiography (IA-DSA) and total runoff contrast-enhanced magnetic resonance angiography (CE-MRA) to demonstrate peripheral arterial anatomy, specifically in patients with chronic critical ischemia and tissue loss. MATERIALS AND METHODS: Twenty-three consecutive patients with chronic critical ischemia and tissue loss underwent CE-MRA and IA-DSA within 2 days. Two teams, consisting of an interventional radiologist and vascular surgeon who were blinded to each other's results, determined the number of named arteries (21 segments) and the presence of >/=50% stenosis or occlusion. RESULTS: Compared with IA-DSA, both teams detected significantly more arterial segments with CE-MRA, both above and below the knee (team 1: above knee 7.0 versus 5.2, P = 0.002, and below knee 8.5 versus 5.4, P < 0.001; team 2: above knee 7.1 versus 5.4, P = 0.004, and below knee 8.3 versus 5.9, P < 0.001). Interobserver agreement between the 2 teams with regard to presence of arteries and the presence of stenoses and/or occlusions yielded kappa values of 0.76 (95% confidence interval 0.71-0.81) for IA-DSA and 0.73 (95% confidence interval 0.66-0.80) for CE-MRA. Treatment was changed based on the CE-MRA findings in 8/23 (35%) patients. CONCLUSIONS: In the present study CE-MRA detected more patent arteries than IA-DSA in patients with chronic critical ischemia and tissue loss. CE-MRA can modify the choice of therapeutic strategy in these patients.


Asunto(s)
Angiografía de Substracción Digital/métodos , Isquemia/diagnóstico , Angiografía por Resonancia Magnética/métodos , Anciano , Anciano de 80 o más Años , Enfermedad Crónica , Medios de Contraste , Femenino , Humanos , Aumento de la Imagen , Masculino , Persona de Mediana Edad
19.
J Vasc Surg ; 37(6): 1255-62, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12764273

RESUMEN

OBJECTIVE: This study was undertaken to investigate the effects of substituting multi-station total outflow contrast medium-enhanced magnetic resonance angiography (CE-MRA) for color duplex ultrasound (US) scanning on treatment planning in the diagnostic workup of patients with suspected or known peripheral arterial occlusive disease. Patients and methods One hundred consecutive patients referred because of suspected or proved peripheral arterial occlusive disease to a University Hospital underwent both aortoiliac duplex US scanning and multi-station total outflow CE-MRA. For 73 of these patients (57% men; mean age, 62 years) treatment or treatment plans could be retraced. Eighteen patients also underwent femoro-popliteal duplex US scanning. Three experienced vascular surgeons retrospectively formulated two sets of treatment plans based on standardized clinical parameters and either duplex US scanning or CE-MRA. The main outcome measure was proportion of patients for whom the treatment plan matched actual treatment without additional use of intra-arterial digital subtraction angiography. Actual treatment, based on all available information, including results of duplex US scanning, CE-MRA, and any other diagnostic tests, served as the standard of reference. RESULTS: Duplex US scanning provided enough information for treatment planning in 46, 45, and 53 patients versus 67, 68, and 66 patients when CE-MRA was used (surgeons 1, 2, and 3, respectively; surgeons 1 and 2, P <.001; surgeon 3, P =.007). Treatment plans based on duplex US scanning exactly matched actual treatment in 37 of 73 patients (51%; surgeon 1), 36 of 73 patients (49%; surgeon 2), and 46 of 73 patients (63%; surgeon 3). Treatment plans based on CE-MRA exactly matched actual treatment in 56 of 73 patients (77%; surgeon 1), 55 of 73 patients (75%; surgeon 2), and 51 of 73 patients (70%; surgeon 3). Positive predictive value and negative predictive value of duplex US scanning as measures of ability to discriminate between surgical and nonsurgical treatment were 0 of 0 (undefined) and 43 of 46 (93%), 1 of 2 (50%) and 40 of 43 (93%), and 5 of 5 (100%) and 44 of 48 (92%) for surgeons 1, 2, and 3, respectively. For CE-MRA, positive and negative predictive values were 11 of 13 (85%) and 50 of 54 (93%), 10 of 12 (83%) and 51 of 56 (91%), and 8 of 13 (62%) and 48 of 53 (91%), respectively, for surgeons 1, 2, and 3. CONCLUSION: Compared with aorto-iliac and femoro-popliteal duplex US scanning, multi-station total outflow CE-MRA is more effective for treatment planning in most patients with known or suspected peripheral arterial occlusive disease.


Asunto(s)
Arteriopatías Oclusivas/diagnóstico por imagen , Protocolos Clínicos , Angiografía por Resonancia Magnética , Enfermedades Vasculares Periféricas/diagnóstico por imagen , Ultrasonografía Doppler en Color , Adulto , Anciano , Anciano de 80 o más Años , Arteriopatías Oclusivas/terapia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Vasculares Periféricas/terapia , Valor Predictivo de las Pruebas , Radiografía , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
20.
Foot Ankle Int ; 24(4): 349-53, 2003 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-12735379

RESUMEN

We test the premise that peak plantar pressure is located directly under the bony prominences in the forefoot region. The right foot of standing volunteers was examined in three different postures by a CT-scanner. The plantar pressure distribution was simultaneously recorded. The position of the metatarsal heads and the sesamoids could be related to the corresponding local peak plantar pressures. The metatarsal heads 1, 4, and 5 had a significantly different position than the local peak plantar pressures. The average difference in distance between the position of the metatarsal heads and the peak plantar pressure showed a significant correlation: on the medial side the head was located more distally to the local peak plantar pressure, on the lateral side more proximally. The findings suggest that normal plantar soft tissue is able to deflect a load. The observations might improve insight into the function of the normal forefoot and might direct further research on the pathological forefoot and on the design of footwear.


Asunto(s)
Antepié Humano/fisiología , Huesos Metatarsianos/fisiología , Adulto , Fenómenos Biomecánicos , Femenino , Antepié Humano/diagnóstico por imagen , Humanos , Masculino , Huesos Metatarsianos/diagnóstico por imagen , Persona de Mediana Edad , Presión , Huesos Sesamoideos/fisiología , Tomografía Computarizada Espiral
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