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Biomedical subjects

M Loew

Publications and source records attributed to M Loew.

At least 37 records · Page 2Linked to original sources

[Traumatic development of rotator cuff lesion. Scientific principles and consequences for expert assessment].

The traumatic etiology of rotator cuff lesions is a matter of controversial discussed in legal assessments. Because of the relatively high prevalence of degenerative changes with increasing age, including partial and complete rotator cuff tears, it may be difficult to demonstrate the cause of an acute traumatic rotator cuff tear. This article presents a review of the literature concerning current knowledge of the anatomy, biomechanics and pathogenesis of rotator cuff pathology. According to this, a catalogue of potentially adequate and inadequate trauma mechanisms is proposed. Another focus of this work is in the post-traumatic diagnostic steps following persistent rotator cuff-deficient shoulder function. X-ray, ultrasound, MRI and operative findings in rotator cuff tears underline the criteria for distinguishing between traumatic and degenerative lesions. From a legal point of view (e.g., private accident insurance, workers compensation claims), various minor and major arguments are defined, which could help the expert in judging the cause of post-traumatic rotator cuff deficiency.

Diagnosis, Differential↗

Shock-wave therapy is effective for chronic calcifying tendinitis of the shoulder.

We report a prospective study of the effects of extracorporeal shock-wave therapy in 195 patients with chronic calcifying tendinitis. In part A 80 patients with chronic symptoms were randomly assigned to a control and three subgroups which had different treatment by low-energy and high-energy shock waves. In part B 115 patients had either one or two high-energy sessions. We recorded subjective, functional and radiological findings at six months after treatment. The results showed energy-dependent success, with relief of pain ranging from 5% in our control group up to 58% after two high-energy sessions. The Constant scores and the radiological disintegration of calcification were also dose-dependent. Shockwave therapy should be considered for chronic pain due to calcific tendinitis which is resistant to conservative treatment.

Adult↗

[ECG changes after paroxetine. 3 case reports].

Selective serotonin reuptake inhibitors (SSRI) are known to exhibit far less cardiac side effects than tricyclic antidepressants. We report three cases in which the SSRI, paroxetine, induced clinically relevant ECG changes in patients with high risk profile. In two cases an increase in QTc time was observed, severe bradycardia was also observed twice.

Aged↗

[Biometric planning of clinical-orthopedic studies. The optimal test].

A determinant for the evidence of a clinical trial is the magnitude of the sample size. The proper sample size can be easily computed with the knowledge of alpha, power and effect size. Standard values for alpha and power in clinical trials are 5% and 90%, respectively. As a consequence, effect size is crucial for the sample size. The effect size has to be determined by the clinician according to medical considerations. Possible consequences of sample sizes that are either too small or too large are discussed with regard to the meaning of alpha, Power and effect size. Trials with improper small sample sizes have a high risk of false negative results, and may subsequently prevent the application of a possibly effective therapy. Trials with improper large sample sizes may result in statistically significant differences without any clinical relevance.

Biometry↗

Validated computation of physiologic flow in a realistic coronary artery branch.

The pulsatile flow field in an anatomically realistic model of the bifurcation of the left anterior descending coronary artery (LAD) and its first diagonal branch (D1) was simulated numerically and measured by laser Doppler anemometry. The inlet velocity profiles used in the computer simulation and in the physical experiments were physiologically realistic. The computational geometric model was developed on the basis of a digitized arterial cast. The curvature of the LAD over the cardiac surface leads to axial velocity profiles which are slightly skewed towards the epicardial wall. Downstream of the bifurcation, a strong skewing occurs towards the flow divider walls as a result of branching. Locally, the wall shear stress component caused by the complex secondary velocity can be as high as the axial component. The wall shear stress representation from a cell-based perspective exhibits low shear stress and large deviation from the time-averaged shear stress direction during systole. In diastole, the instantaneous wall shear stress direction nearly corresponds to the mean direction. The comparison of computed and measured axial velocity results shows generally good agreement. In contrast to computed flow patterns in simpler geometries constructed from cylindrical tubes, the flow field is found to be smoother, presumably reflecting the adaptation of the vascular contour to the contained flow.

Algorithms↗

Distribution, tolerability and tissue compatibility of intrathecal tizanidine in the sheep.

BACKGROUND: Tizanidine (TZD) is an alpha-2-adrenergic drug with potential spinal analgesic action and could be a substitute or additive for intrathecal (i.t.) opiates in chronic pain treatment. However, long-term tolerability and tissue compatibility are not yet established. METHODS: Three sheep were infused intrathecally with TZD up to 4000 micrograms/d over a time period of up to 440 d using implantable drug administration devices; one control animal was infused with vehicle only; standard values were collected from untreated sheep. CSF samples and blood samples were analyzed to determine pharmacokinetics and systemic redistribution. Behavioral effects were studied. The spinal cord tissue was investigated using standard laboratory histology. RESULTS: Bolus kinetics after i.t. injection of TZD are best described by a two-phase model. Elimination half-lives of TZD in CSF were 15 min and 152 min, respectively. Clearance of TZD from lumbar CSF was 0.48 ml/min. Doses higher than 500 microgram i.t. caused dose-dependent motor inactivity and sleepiness. Continuous i.t. TZD up to 4 micrograms/d was well tolerated regarding behavioral, physical activity, heart rate, muscle counts and total protein were detected both in saline and TZD-treated animals, presumably due to local irritation by the catheter and repeated sampling procedures. Histological evaluation of the spinal cord and adjacent tissues showed no abnormalities. CONCLUSION: The long-term intrathecal infusion of TZD is well tolerated and non-toxic in the sheep. The data favor clinical trials in patients with chronic pain.

Adrenergic alpha-Agonists↗

Training environment for inferior vena caval filter placement.

This paper describes a Virtual Environment system designed to aid in training interventional radiologists in inferior vena cava filter placement. It is being developed as part of a VE simulator for a number of surgical and interventional radiology procedures at the Laboratory for Advanced Computer Applications in Medicine at the George Washington University. In this procedure a filter is placed in the inferior vena cava to prevent blood clots from the lower portion of the body from reaching the lungs and causing a pulmonary embolus. The simulation is designed to provide both tutorial and testing modes for the filter placement procedure.

Algorithms↗

[Results of treatment after traumatic shoulder dislocation. Thoracic abduction plaster case or Desault dressing].

In 80 patients with primary traumatic shoulder dislocation treated at the Heidelberg Orthopaedic University Hospital we had a follow-up examination. We wanted to know about age and sex of the patients, the number of redislocations in correlation to time and way of fixation. We had 70% male and 30% female patients with 97.5% of anterior dislocation. The minimum age was 16 and the maximum 87 years with an average of 44 years. 48 patients had a Desault bandage for 2 weeks and 32 had a shoulder-arm plaster cast for 3 weeks. There was no difference between both ways of fixation. We also could not see any better results after more than a 3 weeks' fixation. The most important fact for redislocation is the age and activity of the patients. A young man has a very high risk of redislocation within the first year.

Adolescent↗

[Effect of extracorporeal shockwave therapy on tendinosis calcarea of the shoulder. A preliminary report].

UNLABELLED: The aim of a prospective study was to examine the effects of high energetic shock wave treatment on the course of calcareous tendinitis of the shoulder. 20 patients were entered into the study. Shock waves were applied to the calcifications with a Lithotripter MFL 5000 in two sessions of 2000 impulses each. The shock wave producing energy was 18 kV-22 kV. 6 and 12 weeks after treatment subjective and functional condition was checked by means of a 100-points functional score; all patients underwent x-ray control and MRI imaging. RESULTS: After 12 weeks 14 patients showed a marked improvement of symptoms, the average improvement on score measuring 25 points. The x-rays of 7 patients showed a complete resorption of the calcifications, in 5 cases partial disintegration of the calcium deposits was seen. The overall morbidity was low with 14 patients developing transient hematomas; MRI imaging showed no severe damages of bone and soft tissue.

Adult↗

[Criteria for legal assessment of rotator cuff rupture].

The judgement of the correlation between an accident and a rotator cuff tear has an important role in legal and private accident insurance. Owing to the high morbidity of degenerative alterations and ruptures of the rotator cuff tendons, the causality of an acute traumatic rupture can be difficult to demonstrate, which means assessments are often controversial. In a retrospective study we evaluated 25 orthopaedic assessments and tried to find rules for an objective estimation. The judgement of correlation between trauma and rotator cuff tear should be based on four pillars: history, trauma mechanism, initial findings and course of the functional deficit. Possible mechanisms of traumatic rupture are discussed from various angles. Important clinical findings, e.g. a functional supraspinatus deficit, should be fully documented. X-Rays of both shoulders can lead to indirect demonstration of preexistent changes in the rotator cuff. Sonographic evaluation can show up the rotator cuff tear and demonstrate signs of acute injury. After persistent pain and functional deficit, in a few cases operative and microscopic findings will lead to a correct estimate of causality. Because of the diagnostic uncertainty a 20-point score is introduced for retrospective assessment of the history (2 points), trauma mechanism (3 points), initial clinical, radiological and sonographic findings (10 points) and course of functional deficit (5 points) to evaluate the role of trauma in rotator cuff tears. Using this score trauma can be classified as the main or partial cause or as irrelevant to the pathogenesis of rotator cuff tears.

Adult↗

[New diagnostic criteria for surgical indications in carpal tunnel syndrome].

The difficulties encountered in objectively diagnosing carpal tunnel syndrome are described. A new method for quantitative analysis of skin sensitivity is presented and its value in determining whether surgery is indicated or not illustrated in 134 cases. Postoperative results were evaluated by electroneurography and quantitative analysis of skin sensitivity. It was shown that even in cases with severe thenar atrophy, measurable improvement of the function of the median nerve can be achieved.

Carpal Tunnel Syndrome↗

[Management of unstable pertrochanteric femoral fracture by alloarthroplastic joint replacement].

The treatment of trochanteric fractures of the femur should aim at the reconstruction of the joint function and should allow early weight bearing. In the case of unstable fractures and advanced osteoarthritis of the hip joint the advantages and risks of a total hip replacement have to be compared with different methods of osteosynthesis. We report on 35 patients with trochanteric fractures primarily treated with a total hip replacement. Their perioperative mortality was 9%, the most common complication was a luxation of the replaced hip joint in 3 cases. 1 patient had to be reoperated because of a soft tissue infection. Comparing the literature the primary total hip replacement shows a lower morbidity and mortality rate than complicated methods of osteosynthesis.

Activities of Daily Living↗

[Multiple sclerosis: atrophy of the corpus callosum and psychosyndrome].

Examination with magnetic resonance imaging of 176 patients with multiple sclerosis showed that corpus callosum (CC) atrophy is common. The thinning of the CC depends on the extension of the coalescent periventricular white matter changes. A highly significant association was found between CC-atrophy and, the severity of organic mental disorder.

Atrophy↗

[Sudeck's dystrophy following arthroscopy of the knee joint--a case report].

Many studies and publications have been devoted to Sudeck's syndrome. A much more rare occurrence is described here, namely, after a lesion affecting the lower extremity and knee joint. The case report concerns the typical course of a reflex dystrophy of the knee joint after a mild interior lesion of the knee followed by arthroscopy.

Adult↗

Treatment of calcifying tendinitis of rotator cuff by extracorporeal shock waves: a preliminary report.

This study examined the effects of high-energy shock wave treatment on the course of calcifying tendinitis of the shoulder. Twenty patients were included in the protocol. Shock waves were applied to the calcifications with a lithotripter in two sessions of 2000 pulses each. The energy that produced the shock wave was 18 to 22 kV. Six and 12 weeks after treatment the subjective and functional state was assessed with the Constant score. All patients underwent radiographs and magnetic resonance imaging. At the 12-week follow-up evaluation 15 patients had a marked reduction of symptoms with an average of 30% improvement in the Constant score. Radiographs showed a complete elimination of the calcifications in seven patients, and in five cases a partial disintegration was seen. The overall morbidity was low; 14 patients had a transient subcutaneous hematoma. Magnetic resonance imaging did not show any lasting damage to bone or soft tissue.

Adult↗

Relationship between calcifying tendinitis and subacromial impingement: a prospective radiography and magnetic resonance imaging study.

In a prospective study radiographs and magnetic resonance images of 75 patients with calcifying tendinitis of the rotator cuff were analyzed. The aim was to evaluate any relation between calcifying tendinitis and subacromial impingement. A total of 83% of the calcifications were located in the supraspinatus or the adjoining part of the subscapularis tendon. On T1-weighted images they could be demonstrated with high accuracy as areas of decreased signal intensity. A magnetic resonance imaging categorization of the calcium deposits was carried out by means of a differentiation of form, outline, and density. A partial rotator cuff tear was found in one shoulder; in 11% variable aspects of degenerative alteration of the affected tendon were seen. By analysis of the radiographic outlet view 16% of the cases had a type III acromion. In conclusion, little correlation exists between calcifying tendinitis and additional findings associated with subacromial impingement.

Acromion↗

[Effect of extracorporeal shockwave administration on biological behavior of bone cells in vitro].

AIM: Osteo-destructive effects as well as stimulation of bone growth are often described after extracorporeal shock-wave application (ESWA). A correlation between the applicated energy and outcome is assumed. The purpose of this study was to analyze, whether ESWA has an influence on growth and proliferation of bone cells in vitro. METHODS: Human cancellous bone was cultivated until a confluent cell layer had grown. 5 x 10(5) bone cells were transferred into U-formed tubes, centrifuged and covered with cultivation medium. Thereafter ESWA was applicated in a standardized manner. Number and intensity of ESWA were systematically combined (500, 1000, 2000 and 0.15, 0.26, 0.51 mJ/mm2 energy flux density--EFD, respectively). Ten samples per combination were analyzed. In addition, we examined an untreated control group. Survival, metabolism (alkaline phosphatase activity), type I collagene-synthesis as well as proliferation were determined. RESULTS: There is a decrease of survival after ESWA depending on the number of impulses and intensity (dose-dependent survival). Cell survival was significantly reduced to 40% after 2000 impulses with high energy rates. Metabolism of surviving cells is not altered by ESWA in comparison with controls. Depending on the number but not on the energy of impulses the type I collagene-synthesis of surviving cells decreased. Between the 3rd and the 8th day after ESWA proliferation increased significantly in cell cultures treated with 2000 impulses of medium or high energy rates. CONCLUSIONS: There is a direct relation between dose and effect for ESWA: A minimum number of impulses and EFD is needed to cause effects on bone-cells. This mainly depends on the numbers of impulses. Destruction of cells is a short-time effect of high shock-wave-doses, a medium-term effect is a cell-stimulation.

Alkaline Phosphatase↗