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[Intraoperative and postoperative insertion control of anterior cruciate ligament-plasty. A radiologic measuring method (quadrant method)].

The best proximal insertion for an ACL graft is an anatomic insertion. The anatomic landmarks of this insertion area are well known, but it is sometimes difficult to find these anatomic landmarks during the operation. Thus, it is desirable to have an objective method to control the insertion. This study was undertaken because no description is available how you can localize the projection of the anatomic ALC insertion exactly in an X-ray picture. We dissected ten human cadaveric knees with intact ACLs. The most ventral, dorsal, distal and proximal borders of the insertion area were marked with 4 K-wires. The K-wires were shortened exactly on the bone border of the intercondylar space. Then the knees were X-rayed in a strictly lateral position. Thus, the shortened ends of the K-wires determined the projection of the ACL insertion in the X-ray picture. The center of this marked area was called point K. Then we determined 4 distances in the X-ray picture: distance t: the sagittal diameter of the lateral condyle, measured along the Blumensaat line distance h: the maximal height of the notch distance a: the distance between K and the dorsal border of the condyle, measured along t distance b: the distance between t and K, measured on a perpendicular line on t Distance a is a partial distance of t and distance b is a partial distance of h. Because of varying projection factors and varying knee sizes, absolute values of these distances are not helpful. This is the reason why we expressed a and b as a proportion of t and h. Distance a was measured 24.8% of distance t. Distance b was measured 28.5% of distance h. The maximal deviation of a and b was 2.2% and 2.5%. Therefore, you can say: In a strictly lateral X-ray picture the distance of K (midpoint of proximal ACL insertion) from the dorsal border of the condyle is 24.8% of the whole diameter of the condyle, and the distance of K from the roof of the notch is 28.5% of the notch-height. This method does not depend on the size of the knee and the distance between the X-ray unit and the knee. The only condition is that the X-ray of the knee must be strictly lateral. This method is easy to handle and is reproducible. It can be used intraoperatively if the surgeon is not sure about the right insertion or if the anatomic landmarks cannot be seen exactly. It can be used postoperatively for documentation of the right position of the substitute. It can be used to find out the possible reason for rupture of a transplant (insertion too ventral) before the revision operation.

Anterior Cruciate Ligament↗

[Ethical aspects of randomized clinical trials].

Randomized clinical trials represent the final, essential link between basic medical research and human health. However, their conduction presents very complex ethical problems, since the patient is the actual target of the experiment. Proper randomization, informed consent, and preliminary disclosure of results create deep ethical conflicts between the role of caretaker and that of impartial observer, both played by the same doctor. The dilemma reproduces the conflict between two different ethics. One is based on the inalienable individual rights stemming from the concept of man as an end in himself and not a means to an end. The other, derived from utilitarian philosophies, is based on the benefit for society as a whole. If we agree that randomized clinical trials represent the best method to test the validity of a new treatment, there is no easy solution. The dilemma could be solved by separating the role of the family doctor, committed to the best treatment possible for his patient, from the role of the scientist, committed to the progress of science and humanity. The former is involved in the treatment of individual patients, the latter in clinical and scientific experiments of a therapeutic nature. The patient may trade his rights to the best possible cure for the safety and the efficiency guaranteed by the scientific institution conducting the trial. Trials on relevant issues--expected to produce important results and impeccably designed scientifically--could be endowed with the ethics of science per se and this could be considered equivalent to the individual rights waived by the patient.

Ethics, Medical↗

Abuse, spies and videotape.

Hospital video surveillance of parents has led to convictions for child abuse. But as Anne Gulland reports, concerns remain over both the reliability of the evidence collected and the ethics of nurses' involvement.

Adult↗

Pulsatility and resistance indices in intrarenal arteries of normal adults.

In order to establish the normal range of values of Pulsatility (PI) and Resistance (RI) Indices in the intrarenal vasculature, a study of 50 healthy volunteers (23 males, 27 females), divided into five groups of 10 according to age, was performed with Duplex Doppler ultrasound. Both kidneys were examined in all individuals and, in 12, indices were also compared between upper and lower poles of both kidneys. In addition, repeat examinations were performed in nine subjects on three different days, in order to assess the reproducibility of the method. No differences were found in the mean values of both indices between males and females, upper and lower poles, right and left kidneys. A statistically significant increase (p < 0.01, unpaired t-test) was demonstrated when the oldest age group (7th decade) was compared to the youngest age group (3rd decade). The method appeared remarkably reproducible for RI (4.2-7%), with wider variation in the PI (9.5-22.7%).

Adult↗

[Quantitative volumetric analysis of the hippocampus, amygdala and entorhinal cortex: normative database for the adult Portuguese population].

INTRODUCTION: Atrophy of the hippocampus, amygdala and entorhinal cortex can be found in neurodegenerative diseases, head trauma and epilepsy and are expressed by means of volume reductions. The ability to detect these changes quantitatively depends on accurate comparisons with normative databases. AIM: To present standard magnetic resonance imaging (MRI) volumes of the mesio-temporal lobe structures and an objective statistical methodology for contrasting pathological states. SUBJECTS AND METHODS: Volumes of the right and left hippocampi, amygdalae and entorhinal cortex were measured from MRI in 34 right-handed healthy volunteers, aged 19-52 years. Data were normalized for the individual variation in total intracranial volume. Reproducibility was confirmed by intra/inter-observer tests. The statistical analyses included asymmetry comparisons, correlations between volumes and tests to assess the influence of age, gender and general morphometry (body mass index and height). For each volume, we further defined a normative interval by means of 99% confidence ellipses, accordingly to Hotteling's method. RESULTS: Right-left asymmetry in the volumes of the hippocampus and entorhinal cortex was a normal finding. Structures located in the right hemisphere were larger than the left by a small but statistically significant amount. No asymmetry was found in the amygdala. There was no correlation in-between these volumes. Gender differences were exclusively noted in the absolute amygdala volumes (male > female) but were eliminated by the normalization procedure. No effect of age or morphometry was seen in the absolute or normalized volumes (except for a milder correlation between hippocampal volumes and height). Confidence ellipses were built for every structure and provided a precise reading of the data. Particularly, it allowed for a clear distinction of pathological asymmetries and bilateral cases. CONCLUSION: These normative volumes serve as a reference for the assessment of pathologic groups within similar age-range. The use of a single graphic representation simplifies the clinical interpretation and enhances the precision of the results.

Adult↗

Uniform requirements for manuscripts submitted to biomedical journals. International Committee of Medical Journal Editors.

A small group of editors of general medical journals met informally in Vancouver, British Columbia, in 1978 to establish guidelines for the format of manuscripts submitted to their journals. The group became known as the Vancouver Group. Its requirements for manuscripts, including formats for bibliographic references developed by the US National Library of Medicine (NLM), were first published in 1979. The Vancouver Group expanded and evolved into the International Committee of Medical Journal Editors (ICMJE), which meets annually; gradually it has broadened its concerns. The Committee has produced 5 editions of the Uniform Requirements for Manuscripts Submitted to Biomedical Journals. Over the years, issues have arisen that go beyond manuscript preparation. Some of these issues are now covered in the Uniform Requirements; others are addressed in separate statements. Each statement has been published in a scientific journal. The fifth edition (1997) is an effort to reorganize and reword the fourth edition to increase clarity and address concerns about rights, privacy, descriptions of methods, and other matters. The total content of the Uniform Requirements may be reproduced for educational, not-for-profit purposes without regard for copyright; ICMJE encourages distribution of the material. Journals that agree to use the Uniform Requirements (over 500 do so) are asked to cite the 1997 document in their instructions to authors.

Animal Experimentation↗

[AT-TG (anterior tuberosity-trochlear groove): interobserver variability in CT measurements in subjects with patellar instability].

PURPOSE OF THE STUDY: Measurements between the anterior tuberosity of the tibia and the trochlear groove of the patellar surface of the femur AT-AG) are recognized parameters for exploring patellar instability. Interobserver variability should be less than 4 mm and reproducibility should be greater than 85 per cent for valid measurements. We assessed interobserver variability with CT measurements. MATERIAL AND METHOD: The radiography files (left and right knee) of thirteen patients with patellar instability were examined by six radiologists working in private practice after training in our university center. RESULTS: The results demonstrated major variability with acceptable reproducibility in only 15% of the measurements. Differences greater than 5 mm were observed for 14 groups of values (54 per cent) and greaterd than 8 mm in 5 groups (19 per cent). The spread was mainly related to determinations of the TG point in case of major dysplasia and in defining the precise contour of the tibial tuberosity. Surgical decisions made on the basis of these millimetric values should be made prudently.

Humans↗

Reproducibility of extracranial carotid atherosclerotic lesions assessed by B-mode ultrasound: the Atherosclerosis Risk in Communities Study.

The reproducibility in the identification of carotid artery lesions using B-mode ultrasound was studied in a large random sample selected from the Atherosclerosis Risk in Communities (ARIC) Study. Carotid lesions were defined as plaque with or without acoustic shadowing (indicative of mineralization). A weighted kappa (kappa w) statistic was used as a chance-adjusted measure of repeatability. In the ARIC baseline survey, the kappa w values for the assessment of lesions on repeat reading were 0.47, 0.60 and 0.69 in the left common carotid artery, the carotid bifurcation and the internal carotid artery, respectively. In a repeat scanning, the kappa w values ranged from 0.59 to 0.79 in the left carotid segments. The results were similar in the left and right carotid arteries. Covariates (age, race, gender, body mass index, study center) did not influence the reproducibility. Similar results were also found in both the baseline survey and the first follow-up examination. In conclusion, reproducibility in the assessment of carotid lesions by B-mode ultrasound can be achieved in multicenter studies at fair to good levels of agreement.

Aged↗

Neural mechanisms potentially contributing to the intersegmental phase lag in lamprey.II. Hemisegmental oscillations produced by mutually coupled excitatory neurons.

Most previous models of the spinal central pattern generator (CPG) underlying locomotion in the lamprey have relied on reciprocal inhibition between the left and right side for oscillations to be produced. Here, we have explored the consequences of using self-oscillatory hemisegments. Within a single hemisegment, the oscillations are produced by a network of recurrently coupled excitatory neurons (E neurons) that by themselves are not oscillatory but when coupled together through N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionicacid (AMPA)/kainate transmission can produce oscillations. The bursting mechanism relies on intracellular accumulation of calcium that activates Ca(2+)-dependent K(+). The intracellular calcium is modeled by two different intracellular calcium pools, one of which represents the calcium entry following the action potential, Ca(AP) pool, and the other represents the calcium inflow through the NMDA channels, Ca(NMDA) pool. The Ca(2+)-dependent K(+) activated by these two calcium pools are referred to as K(CaAP) and K(CaNMDA), respectively, and their relative conductances are modulated and increase with the background activation of the network. When changing the background stimulation, the bursting activity in this network can be made to cover a frequency range of 0.5-5.5 Hz with reasonable burst proportions if the adaptation is modulated with the activity. When a chain of such hemisegments are coupled together, a phase lag along the chain can be produced. The local oscillations as well as the phase lag is dependent on the axonal conduction delay as well as the types of excitatory coupling that are assumed, i.e. AMPA/kainate and/or NMDA. When the caudal excitatory projections are extended further than the rostral ones, and assumed to be of approximately equal strength, this kind of network is capable of reproducing several experimental observations such as those occurring during strychnine blockade of the left-right reciprocal inhibition. Addition of reciprocally coupled inhibitory neurons in such a network gives rise to antiphasic activity between the left and right side, but not necessarily to any change of the frequency if the burst proportion of the hemisegmental bursts is well below 50%. Prolongation of the C neuron projection in the rostrocaudal direction restricts the phase lag produced by only the excitatory hemisegmental network by locking together the interburst intervals at different levels of the spinal cord.

Animals↗

[Method of isotopic determination of aortic valve regurgitation].

The index of valvular regurgitation was measured by two techniques after technetium 99 m gamma-cineangiography: the classical technique of comparing left and right ventricular stroke volumes, and the same technique after subtracting the radioactivity arising from the right atrium from the zone of right atrioventricular superposition. The index of valvular regurgitation was calculated in 41 patients with chronic coronary artery disease without valvular regurgitation and also undergoing coronary angiography with 30 degrees right anterior oblique ventriculography, in 8 healthy volunteer subjects, at rest and on exercise; and in 15 patients with chronic aortic regurgitation also undergoing cardiac catheterization and 30 degrees right anterior oblique left ventriculography and aortography. The regurgitant index by the classical technique was 1,25 +/- 0,18; when the index was calculated again after subtracting right atrial radioactivity, a value of 1,05 +/- 0,12 (p less than 0,01) was obtained. The regurgitant index is not affected by left ventricular contractility or by the degree of left ventricular dilatation. On the other hand, this index is affected by the degree of right ventricular dilatation. The valvular regurgitant index did not vary significantly on exercise (1,01 +/- 0,11 to 1,17 +/- 0,16 NS). The isotopic regurgitant fraction deduced from the valvular regurgitant index correlated well with the angiographic regurgitant fraction (R = 0,74; p less than 0,001). The index of valvular regurgitation gives an exact, reliable and reproducible quantification of left sided regurgitant lesions. It is only valid when there is no intracardiac shunt or regurgitant right heart lesion.

Aortic Valve Insufficiency↗

Evaluation of an ultrasonic echo-tracking method for measurements of arterial wall movements in two dimensions.

The longitudinal movement of blood vessel walls has so far gained little or no attention, as it has been presumed that these movements are of a negligible magnitude. However, modern high-resolution ultrasound scanners can demonstrate that the inner layers of the arterial wall exhibit considerable movements in the longitudinal direction. This paper evaluates a new, noninvasive, echo-tracking technique, which simultaneously can track both the radial and the longitudinal movements of the arterial wall with high resolution in vivo. Initially, the method is evaluated in vitro using a specially designed ultrasound phantom, which is attached to and moved by an X-Y system, the movement of which was compared with two high-resolution triangulation lasers. The results show an inaccuracy of 2.5% full scale deflection (fsd), reproducibility of 12 microm and a resolution of 5 microm, which should be more than sufficient for in vivo studies. The ability of the method is also demonstrated in a limited in vivo study in which a preselected part of the inner vessel wall of the right common carotid artery of a healthy volunteer is tracked in two dimensions over many cardiac cycles. The results show well reproducible x-y movement loops in which the recorded radial and longitudinal movements both are of the magnitude millimetre.

Algorithms↗

Contrast echocardiography and transcranial Doppler sonography for detection of a patent foramen ovale.

We report the case of a patient, in whom a patent foramen ovale was detected. For the detection of a patent foramen ovale simulation of Valsalva's manoeuvre with a positive airway pressure of 20 cm H2O was applied. Change of ventilation manoeuvre by ventilation with positive airway pressure of 35/30/15 cm H2O at a tidal volume of 1200 ml make a distinct increase in passage of contrast medium from the right to the left atrium. These findings were detected by contrast transesophageal echocardiography and indirectly by transcranial Doppler sonography and were reproducible. This may stress the importance of preoperative screening of patent foramen ovale in patients to be operated on in the sitting position. Contrast echocardiography and the ventilatory manoeuvre with high airway pressure and PEEP might increase the detection rate of patent foramen ovale with a right to left shunt during general anaesthesia.

Echocardiography↗

Getting it right the second time.

Once a business performs a complex activity well, the parent organization often wants to replicate that success. But doing that is surprisingly difficult, and businesses nearly always fail when they try to reproduce a best practice. The reason? People approaching best-practice replication are overly optimistic and overconfident. They try to perfect an operation that's running nearly flawlessly, or they try to piece together different practices to create the perfect hybrid. Getting it right the second time (and all the times after that) involves adjusting for overconfidence in your own abilities and imposing strict discipline on the process and the organization. The authors studied numerous business settings to find out how organizational routines were successfully reproduced, and they identified five steps for successful replication. First, make sure you've got something that can be copied and that's worth copying. Some processes don't lend themselves to duplication; others can be copied but maybe shouldn't be. Second, work from a single template. It provides proof success, performance measurements, a tactical approach, and a reference for when problems arise. Third, copy the example exactly, and fourth, make changes only after you achieve acceptable results. The people who developed the template have probably already encountered many of the problems you want to "fix," so it's best to create a working system before you introduce changes. Fifth, don't throw away the template. If your copy doesn't work, you can use the template to identify and solve problems. Best-practice replication, while less glamorous than pure innovation, contributes enormously to the bottom line of most companies. The article's examples--Banc One, Rank Xerox, Intel, Starbucks, and Re/Max Israel--prove that exact copying is a non-trivial, challenging accomplishment.

Benchmarking↗

Can natural strain and strain rate quantify regional myocardial deformation? A study in healthy subjects.

Strain rate (SR) and strain (epsilon) have been proposed as new ultrasound (US) indices for quantifying regional wall deformation, and can be measured from color Doppler myocardial data by determining the local spatial velocity gradient. The aim of this study was to define normal regional SR/epsilon values for both radial and longitudinal myocardial deformation. SR/epsilon profiles were obtained from 40 healthy volunteers. For radial deformation, posterior left ventricular (LV) wall SR/epsilon were calculated. For longitudinal, they were determined for basal, mid- and apical segments of the 1. septum; 2. lateral, 3. posterior and 4. anterior LV walls and for the 5. right ventricular (RV) lateral wall. SR/epsilon values describing radial deformation were higher than the corresponding SR/epsilon values obtained for longitudinal deformation. Longitudinal SR/epsilon were homogeneous throughout the septum and all LV walls. This was in contrast to the normal base-apex velocity gradient. The RV segmental SR/epsilon values were higher than those obtained from the corresponding LV wall and inhomogeneous (higher in the apical segments). SR/epsilon imaging appears to be a robust technique for quantifying regional myocardial deformation.

Adult↗

Radiographic values of the adult foot in a standardized population.

Radiographic angular measurements are commonly used in decision making in adult foot and ankle surgery. Unfortunately, there are few controlled studies available to substantiate comprehensive radiographic values in the adult foot. The purpose of this study was to determine the values of a variety of radiographic measurements of the adult foot in a standardized population. A total of 100 participants, 50 men and 50 women (200 feet), were evaluated. Individuals with a history of foot/ankle pain, previous foot/ankle operation or fracture, or a history of systemic disease were excluded from the study. Bilateral weight-bearing digital anterior-posterior and lateral radiographs were taken using a standardized method. In all, 21 measurements were made in the anterior-posterior view and 9 in the lateral view for a total of 6000 measurements. Some traditional measurement techniques of selected angles were found to be not consistently reproducible and alternative consistently reproducible techniques are described. Results are given in table form for maximum, minimum, average, median, and SD. Left and right foot maximum, minimum, and average differences were determined. Differences were also briefly explored for age and sex.

Adult↗

Rate-dependent failure of ventricular capture in patients treated with oral propafenone.

The effects of propafenone on ventricular excitability were studied in 18 patients after 9 +/- 6 days on oral propafenone (900 mg/day). Late diastolic double threshold right ventricular stimulation was performed at variable rates. In five patients (28%, group I) an intermittent, rate-dependent failure of ventricular capture was reproducibly observed during stimulation at rates above the sinus rhythm but not exceeding 150 beats min-1. In four patients loss of capture was preceded by gradual prolongation of the interval between the stimulus artifact and the local right ventricular bipolar electrogram. Such findings were not observed in the remaining 13 patients (group II) on propafenone nor in 28 studies in the same patients on different antiarrhythmic agents. Group I vs group II patients were older (72 +/- 4 vs 53 +/- 18 years, P = 0.002), had longer right ventricular effective refractory periods on the baseline (P = 0.004) and on propafenone (P = 0.0003), and had longer QRS duration on propafenone. The increase produced by propafenone in sinus rhythm QRS duration, paced QRS duration and ventricular effective refractory period was greater in group I than in group II: 42 +/- 36 vs 14 +/- 12 ms, P = 0.01, 94 +/- 43 vs 34 +/- 26 ms, P = 0.0002, 88 +/- 64 vs 22 +/- 37 ms, P = 0.025, respectively. Thus propafenone can produce rate-dependent failure of ventricular capture which is associated with marked prolongation of refractoriness and QRS duration suggesting a marked use-dependent drug effect in selected patients.

Administration, Oral↗

Right heart volumetric monitoring: measuring preload in the critically injured patient.

Accurate assessment of preload status is a major concern in the resuscitation of the critically injured patient. Of the three physiologic determinants of stroke volume, preload is the variable that is most frequently influenced by an insult or intervention or both in the trauma patient. In the critically injured patient, clinicians focus on the preload status to restore and maintain intravascular volume in attempts to optimize cardiac output and oxygen delivery. Until recently, efforts to measure and optimize ventricular preload have focused on intracardiac filling pressures (central venous pressure and pulmonary artery occlusion pressure). The purpose of this review is to discuss the application of volumetric measurements that provide a more accurate means of determining recruitable ventricular preload in the critically injured patient.

Acute Disease↗