Biomedical subjects

V Metz

Publications and source records attributed to V Metz.

At least 19 recordsLinked to original sources

PubMed2003

Shortening of the patellar tendon length does not influence the patellofemoral alignment in a cadaveric model.

INTRODUCTION: Anterior cruciate ligament (ACL) reconstruction with the use of autograft tissue represents the standard treatment. The use of a bone-patellar tendon-bone transplant for symptomatic ACL deficiency achieves good long-term results. The purpose of the study was to investigate in a cadaveric model whether reproducible patellar tendon shortening changes the patellofemoral alignment. MATERIALS AND METHODS: Using five cadaveric knees, an MRI investigation was performed with the patellar tendon left unchanged, shortened 5 mm and shortened 10 mm, respectively, in both 20 and 45 degrees of knee flexion. The lateral patellofemoral and the congruence angles were measured and compared using a one-way analysis of variance for repeated measurements. RESULTS: Shortening the patella tendon by approximately 20% did not significantly influence the patellofemoral alignment. CONCLUSION: Although anterior cruciate ligament-reconstruction using the patellar tendon has become a standard procedure, postoperative problems such as anterior knee pain, and patellofemoral osteoarthritis occur quite often. In this cadaver study we did not find a significant difference for the patellofemoral alignment, irrespective of the patellar tendon length.

Adult↗

PubMed2003

Geochemical evaluation of different groundwater-host rock systems for radioactive waste disposal.

The geochemical suitability of a deep bedrock repository for radioactive waste disposal is determined by the composition of geomatrix and groundwater. Both influence radionuclide solubility, chemical buffer capacity and radionuclide retention. They also determine the chemical compatibility of waste forms, containers and backfill materials. Evaluation of different groundwater-host rock systems is performed by modeling the geochemical environments and the resulting radionuclide concentrations. In order to demonstrate the evaluation method, model calculations are applied to data sets available for various geological formations such as granite, clay and rocksalt. The saturation state of the groundwater-geomatrix system is found to be fundamental for the evaluation process. Hence, calculations are performed to determine if groundwater is in equilibrium with mineral phases of the geological formation. In addition, corrosion of waste forms in different groundwater is examined by means of reaction path modeling. The corrosion reactions change the solution compositions and pH, resulting in significant changes of radionuclide solubilities. The results demonstrate that geochemical modeling of saturation state and compatibility of the host formation environment with the radioactive waste proves to be a feasible tool for evaluation of various sites considered as deep underground repositories.

Corrosion↗

PubMed2002

Galactography: method of choice in pathologic nipple discharge?

Our objective was to assess the role of galactography in the diagnostic work-up of patients with pathological nipple discharge together with exfoliative cytology, and investigation of secretion colour. All galactographies performed in this center between 1993 and 1998 were evaluated retrospectively. In 134 cases, outcomes, defined as either a postoperative histology or a negative follow-up over 2 years after galactography, were available. In 96 of these cases, exfoliative cytology was performed, and in 65 cases the colour of the secretion was determined. Galactograms, cytological findings and colour of the secretions were compared with the outcomes. At galactography, the radiographic findings had the following individual sensitivities/specificities in detecting carcinomas: filling defect 55.6%/62.1%; ductectasia 22.2%/94%; and filling stop 5.6%/77.6%. Normal galactograms (n=33, 25%) had a sensitivity of 78% and a specificity of 93% in predicting absence of disease. Technically inadequate investigations occurred in 16 (12%) cases. Cytology showed 69.2%/66.8% for papillomatous borderline or malignant cells; 53.8%/75.3% for borderline or malignant cells; and 7.7%/100% for one case of malignant cells. For the assessment of pathological secretions, galactography is a sensitive but unspecific method for the detection of papillomas or carcinomas. Filling defects, ductectasia and ductal distortion carry the highest levels of suspicion for carcinoma. A normal galactogram is a specific yet moderately sensitive indicator of absence of localized disease. Exfoliative cytology shows low sensitivity but better specificity for carcinomas when borderline or malignant cells are found. In the present series, the colour of the secretions does not add significant information about underlying pathology.

Aged↗

PubMed2002

[Intravenous administration of iodinated, non-ionic, low or isoosmolar contrast media: safety aspects].

It is the purpose of this review to provide information about the safe use of intravenously administered, iodinated, non-ionic, low or isoosmolar contrast media for radiological examinations, how to avoid adverse events, and how to react professionally in case of an anaphylactic reaction. Methods of prophylaxis and therapy for anaphylactic and chemotoxic effects of contrast media administration as well as absolute and relative contraindications are discussed. Medico-legal considerations of contrast agent administration, informed consent of patients, and methods of risk management for undesired contrast media reactions are considered in this article. Establishment of adminstration standards for contrast media is of tremendous importance to standardize radiological procedures. This basic radiological documentation is part of the institutional and individual legal safety management.

Anaphylaxis↗

PubMed2000

Tracheal agenesis: evaluation by helical computed tomography.

We present a newborn infant with type II tracheal agenesis. Helical CT was performed and confirmed the diagnosis. Retrospective coronal and sagittal multiplanar reconstructions clearly demonstrated the complex anatomy of the malformation. The absence of a significant portion of healthy trachea did not present any possibility for surgical correction.

Fatal Outcome↗

PubMed1998

[Prevalence of abdominal aortic aneurysms: a sonographic screening study].

PURPOSE: To determine the prevalence of abdominal aortic aneurysms (AAA) in males above 60 years of age. METHODS: 1043 males of 60 years of age or older underwent sonographic examinations of the abdominal aorta. All of the candidates had volunteered for the examination, and special care was taken to avoid preselection of the candidates. Wherever possible, information was obtained on the following risk factors: cholesterol level, nicotine, diabetes, insulin and other medication, hypertonia and cardiac risk. RESULTS: An AAA was diagnosed in 2.59% of the cases, while ectasia of the abdominal aorta was detected in 11.89%. The mean diameter of the aneurysms was 39.1 mm. Significant correlations between the various risk factors and abnormalities of the abdominal aorta could be established in patients suffering from angina pectoris (p = 0.004) and from congestive heart failure (p = 0.014). CONCLUSIONS: AAA in males above 60 occurs in 2,590 out of 100,000 cases. The most noteworthy risk factors in the development of AAA are cardiovascular disorders.

Age Factors↗

PubMed1998

Sliding door technique for the repair of midline incisional hernias.

We describe a technique that enables the autologous repair of large midline incisional hernias by restoring the functional musculoaponeurotic support of the abdominal wall. Unlike other methods of hernia repair, the essential step of the sliding door technique is the complete release of the rectus abdominis muscles from the anterior and posterior layers of their sheaths. The released muscles are thus overlapped and sutured together without tension. Another step of the technique is the release of both rectus sheaths by incising the aponeuroses of the external oblique muscles. We report on the use of this technique in 10 patients with midline incisional hernias (mean size of the abdominal musculofascial defect 14 x 11 cm). The patients were examined 14 months to 5.5 years after hernia repair. Two postoperative complications occurred: one marginal skin necrosis and one subcutaneous seroma. Recurrences were not observed. Ultrasound examination showed that the rectus muscles maintained their overlapped position postoperatively. Clinical muscle testing indicated that the strength of the released rectus muscles provides functional support to the reconstructed anterior abdominal wall.

Abdominal Muscles↗

PubMed1998

Patellar alignment evaluated by MRI.

We analyzed the congruence of the articular cartilage surfaces and the corresponding subchondral bone in the patellar joint. 20 volunteers underwent MRI investigations of the right patellar joint in 20 degree and 45 degree flexion in the axial plane. The sulcus, congruence, and lateral patellofemoral angles, measured on MRI slices centered through the midtransverse patella, were recorded. In 20 degree and 45 degree knee flexion, the bony sulcus and lateral patellofemoral angles were significantly different from the respective cartilagineous angle. We conclude that 1) measurement of the bony sulcus and lateral patellofemoral angles does not allow conclusions about the articular cartilage surface and its thickness, 2) the bony congruence angle corresponds well to the articular cartilage surface as an indicator of patellar centralization.

Anthropometry↗

PubMed1993

[Ultrasound-guided needle biopsies of thoracic space-occupying lesions].

This study is concerned with the results and experience gained from performing ultrasound-guided needle biopsies of thoracic masses in 56 patients. The accuracy of the biopsy results were related to the certainty of the method, the visibility of the biopsy needle on real time images, the effect of biopsy needle thickness and tumour size. Correct diagnosis was achieved in 84.6%. Inability to see the biopsy needle resulted in only 5.4% of cases and only when using a low frequency transducer (3 MHz). The thickness of the biopsy needle affected the accuracy of the biopsy, since all false negative or inconclusive biopsies resulted from the use of fine calibre needles. There was no significant correlation between tumour size and the accuracy of the biopsy results.

Adult↗

PubMed1993

[Stenoses and occlusions of the abdominal aorta in patients less than 40-years old].

Stenosis or occlusion of the abdominal aorta in patients under 40 years of age is either due to a congenital malformation (abdominal aortic coarctation) or due to idiopathic aortitis (Takayasu's arteritis). Some authors, however, consider abdominal aortic coarctation as a subtype of Takayasu's arteritis. We evaluated 9 of our cases and 108 well-documented cases from the literature to help decide the question whether abdominal aortic coarctation is an entity of its own or a subtype of Takayasu's arteritis. In coarctation there is a slight male predominance, patients are usually younger than 20 years of age, and the short aortic stenosis is suprarenal with involvement of the renal arteries. In Takayasu's arteritis females are predominantly affected, patients are usually over 20 years of age, and the long aortic stenosis or occlusion is infrarenal without involvement of the renal arteries. Abdominal aortic coarctation must therefore be considered as a separate disease. Aortography is important, because the morphology of aortic alterations often allows a radiological diagnosis.

Adult↗

PubMed1993

[Valve saving correction of aneurysms of the ascending aorta with aortic insufficiency or annular dilatation].

The current technique to correct aneurysms of the ascending aorta with incompetence of the aortic valve or dilatation of the aortic root is the implantation of a valved conduit. In many cases however structurally normal aortic leaflets are resected by this technique and patients are at the risk of complications due to mechanical heart valve prostheses and the necessary anticoagulation respectively. By resuspension of the aortic valve into the aortic prostheses similar to the technique used at implantation of homograft valves, competence of the valve can be restored and the dilatation of the aortic annulus can be prevented or even reduced. Our article describes the successful, valve sparing correction of an acute aortic dissection type A with dilatation of the aortic annulus in a 43 year old patient and in another patient with ascending aortic aneurysm with aortic insufficiency.

Adult↗

PubMed1992

Color Doppler imaging of inferior vena cava: identification of tumor thrombus.

Color-coded Doppler sonography (CCDS) was used for the examination of tumor thrombus (n = 7) and benign thrombosis (n = 6) of the inferior vena cava. Tumor thrombus was due to hepatocellular carcinoma in two cases and to renal cell carcinoma in five cases. Whereas no specific information about the nature of thrombus formation could be gained by gray scale sonography, a typical patchy vascularization pattern was noted within tumor thrombi in six of seven cases using CCDS. This ws due to marked neovascularization within the tumor thrombi, confirmed by histologic examination in all cases. In one patient no vascularization within the tumor thrombus could be observed by CCDS because the thrombus was relatively small. In patients with bland thrombosis, either no vascularization of the thrombus was seen (n = 5) or linear recanalization of the thrombus occurred (n = 1). Therefore, it might be possible to differentiate tumor from nontumor thrombus in the inferior vena cava by using CCDS. Further studies are needed to confirm this preliminary hypothesis.

Adult↗

PubMed1992

["Pseudo-dissection" in an abdominal aortic aneurysm].

Sonography of 52 patients with aneurysms of the abdominal aorta revealed in 7 cases hypoechoic crescent-like zone between parietal thrombus and the aortic wall which simulated aortic dissection. Duplex-sonography was performed in all cases and no flow could be detected in this area. In two patients intraoperatively several milliliters of a serous fluid could be aspirated from this zone which confirmed the suggestion of seroma within the parietal thrombus. This observation may be found rather frequently and should not be a reason for immediate surgery.

Aortic Dissection↗

PubMed1992

[Aneurysms of the portal vein: an evaluation of 21 cases].

Reviewing 17 cases from the literature and 4 own cases we tried to throw light on the clinical and radiological appearance of the aneurysms of portal vein. The evaluation was performed in respect of sex, age, size, localisation and eventual combination with a portal hypertension. It appears that these aneurysms can be found at any age and that there is no sexual preference. In most cases these aneurysms are asymptomatic. In rare cases they may cause portal hypertension. This seems to be possible only with extrahepatic but not with intrahepatic location of the aneurysms.

Adult↗

PubMed1991

[The value of different clinical and imaging procedures for the postoperative follow-up of extra-anatomical bypasses].

In order to judge the patency of extra-anatomical by-passes in the lower extremities, 24 patients with 29 by-passes were examined clinically (palpation of the by-pass pulse, Fontaine staging, Doppler index) and by imaging methods (i-v DSA, Duplex sonography, colour-coded Doppler sonography). The value of these methods was compared. Sonography was found to be the ideal method for follow-up. Palpation was unreliable, particularly for femoro-femoral by-passes. The Doppler index and the Fontaine method provided no information about the actual state of the bypass. Angiography is indicated only if further vascular reconstruction is planned.

Aged↗

PubMed1991

[The value of mammography in patients up to the age of 35].

The use of mammography in young women is under debate. In this prospective study of 220 women aged up to 35 years, the indications for mammography were compared with the final diagnosis. In this way, an attempt was made to define the signs and symptoms that justify mammography in this age group. The results show that mammography is indicated only in the presence of palpable lumps. All other signs or symptoms should not be investigated by means of ionising radiation in this particular age bracket.

Adolescent↗

PubMed1991

[Value of supine thoracic radiography in the diagnosis and quantification of pleural effusions: comparison with sonography].

The purpose of this prospective study was to verify the value of the supine chest radiograph with regard to the recognition and quantification of pleural effusions. The findings of supine chest radiographs were compared to those of chest sonography in a total of 320 pleural cavities. The correct identification and quantification of a pleural effusion was possible by supine chest radiograph alone in only 55% of cases (176/320). In 20% (64/320) supine chest x-ray was falsely negative and in 15% (48/320) falsely positive. In 10% an existing effusion was in fact recognised on supine chest x-ray; however the amount of effusion was wrongly estimated.

Adolescent↗

PubMed1991

[Percutaneous transluminal implantation of the Günther cava filter: experience based on 22 patients].

During the last three years, Günther cava filters were implanted in 20/22 patients. The indications for the procedure were single pulmonary emboli in 4, recurrent pulmonary emboli in 6 and pelvic vein thromboses with free thrombus but without pulmonary emboli in 12. In 2 patients implantation of the cava filter could not be carried out because of low position of the renal veins. 15 patients were re-examined 2 weeks to 20 months after the introduction of the filter. In no cases was there clinical evidence of recurrent pulmonary emboli. Occlusion of the inferior vena cava was demonstrated in 1 patient and downward displacement of the cava filter in 6 patients. Perforation of at least one prong of the filter through the wall of the inferior vena cava could be recognized in 4 patients. In 1 patient there was fracture of one leg of the filter but this was clinically not apparent.

Adult↗