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Biomedical subjects

W Birg

Publications and source records attributed to W Birg.

At least 19 recordsLinked to original sources
PubMed1991

Long-term outcome of 89 low-grade brain-stem gliomas after interstitial radiation therapy.

Between 1974 and 1985, 89 patients suffering from histologically confirmed, nonresectable low-grade astrocytomas located in the brain stem were entered into a retrospective study. Iodine-125 (125I) was implanted in 29 patients and iridium-192 (192Ir) in 26 patients. Computerized tomography revealed that 78% of the tumors in these patients were located chiefly in the mesencephalic region, 70% were circumscribed, and 78% were contrast-enhanced. Thirty-four patients underwent biopsy without prior aggressive tumor-specific therapy such as chemotherapy or external beam irradiation. Among these, 70% of the tumors were located predominantly in the pons, 74% were diffuse, and 59% were hypodense or isodense after contrast enhancement. Long-term follow-up investigations indicated that life expectancy after interstitial radiation therapy with 125I implanted directly by catheter either permanently or temporarily showed a more favorable trend than that after treatment with 192Ir. Interstitial radiation therapy with 125I appears to be an effective treatment for slowly proliferating, differentiated, well-delineated, nonresectable brain-stem gliomas. This technique makes it possible to achieve radiosurgical tumor control and, when carefully applied, represents the least traumatic treatment. Reduction of the tumor mass brings about improvement of the clinical symptoms. Further investigations on the biological behavior of brain-stem gliomas and prospective randomized long-term follow-up studies are necessary to evaluate the different kinds of treatment available for these patients.

Adolescent↗
PubMed1989

Stereotactic interstitial irradiation of diencephalic tumors with iridium 192 and iodine 125: 10 years follow-up and comparison with other treatments.

The only possible treatment of non-removable tumors of the diencephalon or recurring tumors invading the diencephalon after partial resection or percutaneous radiotherapy is interstitial irradiation (Curie therapy). With the CT/MRI stereotactic method, biopsy for histological tumor classification can be performed and 125I or 192Ir implanted, provided the neuroimaging methods show the delimitation of the tumor, its diameter does not exceed 3 cm and, given the patient's condition, focal irradiation seems advisable. As of 31 August 1987, a total of 1883 cases had been stereotactically biopsied and interstitially irradiated. The indications and results are reported in 204 patients under 18 years of age with diencephalic and deep-seated astrocytomas, after a follow-up period of up to 10 years; the data were compared for tumor resection, percutaneous irradiation, and for interstitial irradiation. The latter proved to be the most effective treatment.

Adolescent↗
PubMed1988

Neuropsychological assessment of the transcallosal approach.

The long-term consequences of partial callosal lesions were examined in 7 neurosurgically treated patients. Detailed clinical and neuropsychological assessment of the interhemispheric transfer (multimodal sensory and motor tasks) as well as memory and attention tests were used. The results revealed some disconnection symptoms with minor clinical significance, which could not be attributed to particular sites of the corpus callosum, except the splenium. It is questionable whether the reported memory and attention impairments are caused by the callosal lesion or by extracallosal pathology. The results indicate that the transcallosal approach is a safe and feasible alternative in the management of pathological midline processes in the brain.

Adolescent↗
PubMed1985

Long-term effects of partial callosal lesions. Preliminary report.

Ten patients with partial callosal lesions were investigated with a broad scale neuropsychological assessment. Nine patients with a variety of lesions affecting midline structures have been operated using a direct transcallosal approach, one patient with a callosal lipoma remained unoperated. Sophisticated studies of the interhemispheric transfer of somaesthetic and perceptual motor tasks, as well as psychometric testing related to parameters of memory and attention performance were applied. The results indicate that there is no clear correlation between the site of callosal lesion and clinical symptoms. Although special disconnecting symptoms due to callosal dissection could be found, they didn't reach clinical significance. The most severe symptoms of impairment were caused by the extracallosal pathology. The results indicate that the transcallosal approach is a safe and feasible alternative in the management of pathological lesions in the midline region.

Adolescent↗
PubMed1985

Piracetam improves visuomotor and cognitive deficits in early Parkinsonism--a pilot study.

The influence of Piracetam on Parkinsonism was studied in 18 patients and 18 matched controls. Clinical, visuomotor and psychometric variables were measured. Piracetam improved visuomotor reaction time (RT) and accuracy in 6 mildly affected and tracing time in 6 moderately affected patients, the clinical condition and the organic brain syndrome in all patients investigated. The improvement of the prolonged RT seems to be correlated with bradyphrenia. No drug influence could be observed in the prolonged interhemispheric transfer time. As the mildly affected patients displayed the clearest effect of Piracetam, its administration in early and mild stage of parkinsonism is recommended.

Aged↗
PubMed1985

X-ray and magnetic resonance stereotaxy for functional and nonfunctional neurosurgery.

By means of new plastic stereotactic ring and head fixers, stereotactic procedures can be combined with MRI, with stereotactic coordinates obtained from the MRI images. The method was rechecked against CT stereotaxy and shows a good correspondence of the target coordinates. With MRI stereotaxy, structures near bony regions will be more accessible than with CT stereotaxy. Moreover, the MRI procedure seems to have advantages for functional therapy without the necessity of contrast ventriculography.

Brain Neoplasms↗
PubMed1979

[Objectivation of tremor and motion disorders via computerisation (author's transl)].

The quantitative analysis of motion disorders of the upper extremities can be performed by means of a joystick connected with a minicomputer. Therefore a random squarewave curve is drawn on a computer display and the patient must follow it with the joystick. The deviation of the two curves are recorded, analysed and documented numerically and graphically.

Diagnosis, Computer-Assisted↗
PubMed1978

Treatment of small cerebral gliomas with CT-aided stereotaxic curietherapy.

In cases of stereotaxic irradiation of small tumors, CT makes possible a precise determination of tumor volume and dosage and permits exact positioning of the therapy probe. Iridium 192 wires are interstitially implanted in the tumor (mostly gliomas Grades I-III) after biopsy. The results with 98 CT-controlled patients (from a series of 213 implantations in midline tumors) have provided new information about the method of treating small cerebral gliomas.

Brain Neoplasms↗
PubMed1978

Computer-assisted stereotactic brain operations by means including computerized axial tomography.

With a computerized program system for stereotactic brain operations it becomes possible for the first time to react even before running a possible risk, e.g., in case of punctures in the midbrain, the brain stem, or in the hypothalamus, by simulating the operative procedure even before starting the operation itself. This is effected by the ability to change the penetration angle of the electrode or by choosing a different point of trepanation. The inclusion of computerized axial tomography, especially through the presentation of the CT scan, made to measure with the help of the linear transformation, and of the input of the cranial and ventricular coordinates through a digitizer, together with the coordinates resulting from the X-ray picture, brings the definition of the target point to a still greater optimum. Thus the safety and the precision of the stereotactic operation have been improved even further.

Brain↗
PubMed1977

A computer programme system for stereotactic neurosurgery.

A computer programme system is reported which allows a simulation of a stereotactic operation. It incorporates the determination of intracerebral structures and the electrode tract by means of boney reference points as well as the calculation of the parameters for the stereotactic apparatus. It contains further a library of brain sections, by which the electrode tract within the target structures can be shown on a computer display.

Computers↗
PubMed1976

The entity of non occlusive mesenteric ischemia: strophanthin effect on mesenteric blood flow in experimental animals.

Digitalis glycosides have the well known positive inotropic effect on the heart. Their effect on extracardiac vascular smooth muscle receives increasing attention. In experimental animals a significant decrease in mesenteric blood flow and an increase in mesenteric vascular resistance could be shown. Angiography of main mesenteric arteries, smaller arteries, and arterioles reveal typical vasoconstriction. Angiomorphometric measurements show good correlation between the decrease in vascular diameter and the increase in vascular resistance.

Animals↗
PubMed1975

Determination of intracerebral structures using osseous reference points for computer-aided stereotactic operations.

Computer-aided sterotactic neurosurgery can be improved and simplified by using craniocerebral parameters for the calculation of subcortical target points and avoiding an air-filling of the ventricles. This was achieved by selecting 403 pneumo-encephalographic studies at random, measuring the craniocerebral parameters according to age and sex. There is a correlation between the bony cranium and the brain axis. We established a formula and a table to determine in the plain X-ray the entrance of the foramen of Monroi with a standard deviation of +/- 1.5 mm and the inclination of the intracerebral basic line we used (foramen Monroi-commissura posterior). With this information various subcortical targets can be determined by means of computer programs.

Aged↗