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Biomedical subjects

F Alesch

Publications and source records attributed to F Alesch.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Intraventricular morphine administration as a treatment possibility for patients with intractable pain].

The treatment of intractable pain, especially in cancer patients, often sets problems to patient and therapist. While epidural and intrathecal spinal administration of opiates is a routine treatment in pain with a sub-diaphragmatic topography it is almost ineffective in cervicocephalic or thoracic cancer. An alternative here is the administration of morphine into the lateral or third ventricle by a catheter-reservoir system. We report on our experience in the treatment of twenty patients, mostly suffering from cancer (18 cases), from 1990 to 1993. It is shown to be an effective, non-destructive method with minimal side effects in the treatment of nociceptive pain. Analgesia takes effect within a few minutes and the necessary doses are low. Our results agree with those of other authors describing good to excellent results in 95% of patients with somatogenic pain. However, no or only minimal effect is achieved in the treatment of neurogenic pain by intracerebroventricular morphine therapy.

Brain↗
PubMed1995

The role of stereotactic biopsy in radiosurgery.

Radiosurgery offers a very powerful, minimally invasive therapeutic tool in the modern treatment of intracranial lesions. A direct contact with the lesion, as always takes place, e.g. in a stereotactic biopsy or microsurgical operation, is no longer an absolute prerequisite. Treatment planning is done using modern imaging techniques like computer assisted tomography (CT) or magnetic resonance imaging (MRI). Both provide high resolution and contrast images. The lesions can be displayed with high accuracy. The specificity of these techniques is adequate enough to provide neuropathological data which are a prerequisite for treatment? In 1991 we published a retrospective study in which the diagnosis based on CT was compared with the histological diagnosis following stereotactic biopsy on a series of 181 patients with intracranial processes. We could show clearly that CT alone does not offer a reliable basis for therapy planning. Overall CT-scan was inaccurate in 22% of the cases. Now in an additional series of 195 patients with intracranial processes, we have compared the MRI diagnosis with the neuropathological diagnosis. MRI results and the neuropathological diagnosis based on microsurgical operation were compared and evaluated according to the following criteria: 1. Absolute agreement between MRI and histological diagnosis. 2. No agreement between MRI and histological diagnosis. 3. Conditional agreement: the MRI result offered several differential diagnoses one of which was accurate.

Biopsy, Needle↗
PubMed1995

Interstitial irradiation of brain metastases.

Randomized studies have shown that survival in patients with single brain metastases is significantly higher after the combined treatment of surgical removal and whole-brain irradiation than after whole-brain radiation therapy alone. In patients with deep-seated lesions or those located in critical sites of the brain, as well as in cases in which the patient's general condition makes general anaesthesia difficult or impossible microsurgical resection usually cannot be performed or only with an increased surgical risk. Stereotactic radiosurgery, which can be done by means of convergent beam irradiation or by the implantation of highly loaded 125I seeds, provides an alternative to open procedures. In the following we report on our results using a stereotactic radiosurgical technique. A series of 20 treatments is presented, in which biopsy was performed and 125I seeds were implanted, both under stereotactic conditions in the same session. The 125I seeds were sealed in a teflon catheter, were left indwelling temporarily, and then removed after application of the prescribed radiation dose (6,000cGy at the tumour margin). There was only one recurrence in our series, complications occurred in only one patient by temporary aggravation of a pre-existing hemiparesis. Our results indicate that interstitial irradiation of brain metastases is a valuable, less stressful alternative to both open microsurgery as well as to stereotactic radiosurgical convergent beam irradiation.

Adult↗
PubMed1995

Stimulation of the ventral intermediate thalamic nucleus in tremor dominated Parkinson's disease and essential tremor.

Based on Benabid's experimental and clinical findings that low-frequency (50 Hz) electrical stimulation of the ventral intermediate thalamic nucleus may increase tremor, while higher frequencies (> 100 Hz) lead to suppression of the tremor, we implanted a stimulation electrode in 33 thalami among 27 patients. Six patients were implanted bilaterally. 23 suffered from Parkinson's disease, 4 from essential tremor. All patients had a drug-resistant tremor. The Vim target was calculated based on stereotactic ventriculography. An intra-operative neurophysiological target control was performed on all patients. After a monopolar (12 thalami) or quadripolar (21 thalami) lead was implanted we then connected it to a percutaneous extension lead. In the days following the surgery a test stimulation was performed. In all but one patient stimulation resulted in a suppression of the tremor. In a second procedure, a pulse generator (ITREL II; MEDTRONIC) was implanted and connected subcutaneously to the thalamic lead. After implantation of the pulse generator all patients stimulate chronically while some turn off the stimulator at night. In 21 thalami total suppression of tremor was observed, 6 showed major improvement, 4 only minor improvement. There was no significant effect on any other existing symptom of Parkinson's disease. Due to the proximity of Vim to the sensory thalamus the majority of the patients (27 thalami) report slight temporary paraesthesias when the pulse generator is turned on. Two report permanent paraesthesias when stimulation is on. In 4 cases a slight dysarthria occurs under stimulation. In 2 the dysarthria is marked. In one case dysequilibrium occurs under stimulation. All these side effects are reversible when stimulation is turned off. In 3 patients, the lead was displaced due to an insufficient lead fixation, thus making a second procedure necessary to correct the electrode position. We had one complication due to bleeding at the burr hole side. Follow-up ranges from 3 to 48 months. So far in no cases has the effect of stimulation worn off. In conclusion we regard Vim neurostimulation as an effective and safe alternative to conventional thalamotomy and recommend that it should be considered in cases in which drug therapy has failed to affect Parkinsonian or essential tremor. Moreover, we believe that this procedure is a less invasive and equally efficient alternative to classic thalamotomy and thus should be given preference.

Adult↗
PubMed1995

Diagnostic value of stereotactic biopsy of cerebral lesions in patients with AIDS.

A neurological complication occurs in 40-60% of HIV infected patients during the course of the disease. In 10-20% the neurological complication is the first manifestation of the HIV infection. A reliable neuropathological diagnosis is a prerequisite for a specifically selected treatment. While modern computer-assisted imaging techniques, such as computed tomography or magnetic resonance imaging, do possess a high sensitivity, they do not as a rule permit an unambiguous diagnosis. Between October 1989 and July 1994 we biopsied 38 HIV infected patients stereotactically. The indication for the biopsy was determined by having radiologically detectable lesions with no regression tendency in patients under antitoxoplasmosis therapy. In 89% an unambiguous diagnosis was made based on the biopsy; 11% of the biopsies were not diagnostic. For the most part, toxoplasmosis (31%) and progressive multifocal leucoencephalopathy (29%) were involved. 18% of the patients suffered from a non-Hodgkin lymphoma. The foci were primarily frontal (47%), parietal (21%) or localised in the basal ganglia area (11%). The result of the biopsy led to a change in treatment for 52% of the patients. Morbidity and mortality of the operation were 0%. The results or our research series are similar to other groups. It was shown that stereotactic brain biopsy is a safe and effective method for establishing a sound basis for treating the frequently life-threatening cerebral complications of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Computer-assisted multidimensional atlas for functional stereotaxy.

Functional stereotactic operations are currently performed primarily for medically uncontrollable Parkinson's disease and pain. In contrast to the targets in neuro-oncology, those in functional stereotaxy cannot be represented directly by modern imaging methods. The target co-ordinates must therefore be calculated with the aid of special stereotactic atlases. These are publications in which a model brain has been constructed from autopsy examinations on a number of brains, or the data obtained have been compiled in the form of tables and histograms on which the calculation is then based. The target can then be determined based on the classic stereotactic landmarks and reference lines, such as the anterior commissure (AC), the foramen of Monro (FM), the posterior commissure (PC) or the base line FM-PC or AC-PC and the height of thalamus, taking into account the interindividually different anatomical proportions. Since the computational procedures involve repetitious algorithms, it was obvious that such procedures should be run by a computer program. For the most common stereotactic targets, we have developed a computer program for data storage on the one hand and computation and graphic output on the other. The output can be displayed on the monitor and can also be plotted out on paper or overhead transparency. Calibrating between the program and printer renders a 1:1 reproduction, i.e. the graph can be superimposed directly onto original x-rays or images from computed tomography or nuclear magnetic imaging. The graph can be plotted in the three dimensions of the Cartesian co-ordinate system. An additional dimension can be attained by simultaneously including and plotting the data from different atlases and thus from different authors, including one's own data. In addition to the information capacity which this system offers, it also makes possible a considerable reduction in the time for computing the target while at the same time increasing the reliability.

Algorithms↗
PubMed1995

[Neurosurgical methods in Parkinson disease].

Advances in modern drug therapy of Parkinson's disease (PD) have displaced the surgical treatment of illness to second place. Beyond question, the modern medicinal treatment is the therapy of first choice for PD. However, at the same time it should not be forgotten that the stereotactic methods have a high therapeutic potential and should always be used for treating PD whenever medicinal therapy is unsuccessful or is not tolerated. For tremor this is sometimes the case. Neurostimulation, currently the most important neurosurgical treatment, involves a reversible, nonlesional procedure through which tremor can be successfully brought under control in 88% of the cases. Moreover, even the remaining PD symptoms can be targeted and successfully treated by neurostimulation.

Brain Mapping↗
PubMed1994

Prognostic factors in the treatment of cerebellar haemorrhage.

A prospective study for the treatment of cerebellar haemorrhage was conducted in a non-selected group of 33 patients. All patients with cerebellar haemorrhage arriving at the Department of Neurosurgery at Homburg/Saar have been included in this study, also those in bad condition, with high risk factors, and the aged. All of them required intensive care respectively intensive supervision. The following management protocol has been established. I. Cases with small haemorrhage, in good clinical condition, without hydrocephalus and/or occlusion of the basal cisterns: intensive supervision, operative intervention only if they deteriorate into one of the following groups. II. Cases with hydrocephalus-even if not yet pronounced-but without occluded basal cisterns and without major tonsillar herniation: pressure monitored ventricular drainage, which opens at 15 mm Hg and thus prevents higher CSF pressure developing. III. a): Cases with large haematoma, occluded basal cisterns and/or tonsillar herniation, but without severe general risk factors, as a first step: pressure monitored ventricular drainage; as a second step, if they do not improve soon after the normalization of the ventricular pressure: open surgical evacuation of the haematoma, which also decompresses the posterior fossa. If present and possible, causative vascular malformations may be dealt with at the same session. III. b): Same intracranial situation, but patients with severe general risk factors: pressure monitored ventricular drainage only. IV. Cases with causative aneurysm or angioma, who initially had been treated conservatively or by ventricular drainage: secondary operation of the vascular malformation after stabilization of the general conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

A simple technique for making a stereotactic localiser both CT and MRI compatible. Technical note.

Stereotactic neurosurgery requires the utmost precision. This can be achieved with modern imaging methods, provided special localisers are used which produce reference points for the calculation of stereotactic coordinates. Since not every substance can be visualised in every imaging modality, various localisers are normally used. These contain, for example, thin steel wires for CT or copper sulphate for MRI. By using a mixture of jopamidol and copper sulphate at a ratio of 1:1, it is possible to make the reference points of a localiser visible in both CT as well as in MRI. In this way, the entire stereotactic planning can be carried out using only one single localiser. This not only simplifies the procedure, it also reduces costs.

Copper↗
PubMed1992

Marking of the stereotactic target point by a radiopaque silicone sphere. Technical note.

We present a simple but efficient technique for marking the site of a stereotactic biopsy. This is done by a radiopaque Barium impregnated silicone sphere, which is introduced through the stereotactic cannula and placed at the target point. This allows a postoperative check of the target point by computer tomography or Magnetic Resonance Imaging and offers a landmark for further stereotactic intervention as well as for planning of high precision radiotherapy. Moreover it gives information about the growing direction of a tumour. The silicone spheres are well tolerated; no complications have occurred so far.

Biopsy↗
PubMed1992

[Stereotaxic biopsy of cerebral lesions. Results based on a series of 250 cases].

With the help of modern computer-assisted imaging techniques, direct evidence of intracerebral lesions can be provided earlier and in more detail, often before the patient begins to exhibit symptoms. In asymptomatic cases, however, it is often difficult to establish an indication for a certain therapy. The choice of treatment chiefly depends on the histological nature of the lesion. Even in the age of computer-assisted imaging techniques, the specific diagnosis can only be made under the microscope. CT-guided stereotactic biopsy is a valuable and safe diagnostic tool for classifying intracranial lesions. It provides the basis for selecting the appropriate therapy, whether it be surgery, radiotherapy, or conservative treatment. We present a series of 250 stereotactic biopsies. The indications, technique, complications and limits of the method are discussed, as well as the diagnostic yield which achieved 97.6% in our series.

Biopsy, Needle↗
PubMed1991

Diagnostic potential of stereotactic biopsy of midline lesions.

The technique of CT-guided stereotactic biopsy is described and its reliability is discussed based on the experiences with a series of 1747 procedures. We could show that stereotactic biopsy has an overall diagnostic accuracy of 95% and therefore is a safe and reliable tool for planning the therapeutic strategy.

Biopsy↗
PubMed1991

[The use of personal computers for the collection, storage and analysis of data from neurosurgical intensive care monitoring].

For data acquisition intensive care neurosurgery increasingly has recourse to modern electronics, which have become an integral part of many aspects of present-day neurosurgery. Despite their high technical standard, the devices in common use often lack flexibility. Their range of possible applications is defined by the manufacturer, and the user has little or no influence on them. Moreover, there are often no adequate interfaces to peripherals, and the storage capacity is limited. We would like to present a data acquisition system on a PC/AT basis, which operates up to 64 channels allowing parallel registration, storage, analysis, and of decisive importance, also various computations, i.e. correlation. Computation is rarely feasible on commercial devices, but it is essential for specific demands, such as implementation of PA/PM diagrams to determine intracranial compliance. In addition, the pertinent software permits implementation of Fourier analyses, offers separate statistical functions, and transfers data to other programs. The program is capable of automatic batch-processing, which greatly facilitates its use.

Computer Systems↗
PubMed1990

[The technique of stereotactic I125 brachytherapy (permanent implants) of brain tumors in Vienna].

Methods of stereotactic target localisation are used in brachytherapy of brain tumors for many years. Since 1987 eight patients with inoperable astrocytomas grade I to III were treated at the Neurosurgical Clinic and Clinic for Radiotherapy of the University Vienna by permanent stereotactic I125-seed implantation. For that purpose a newly developed applicator was used. Preliminary results confine the low risk of operation, but the follow-up time is too short for evaluation of the treatment success. Principal problems of brain brachytherapy are discussed in the light of international data. In general, I125 brachytherapy is a useful and well tolerated way of treatment of low grade astrocytomas, the risk is low, which is especially important for children and old patients.

Astrocytoma↗
PubMed1987

[Epidural intracranial measurement of pressure using conventional pressure transducers. Introduction of a new method].

Today there are no doubts about the great significance of continuous measurement of intracranial pressure in neuromonitoring. Numerous systems of measurement have been evolved and are available. However, they are rather costly because of their minute size that makes them not only expensive to buy but also to maintain on account of their susceptibility to disturbances and their vulnerability. Hence, the author presents as an alternative to the conventional measurement systems a simple measurement method with a low susceptibility to faults and, above all, at a reasonable price. This method works satisfactorily with the conventional pressure sensors that are usually employed in intraarterial blood pressure measurement. In contrast to the normal procedure, however, the sensors are not implanted; the intracranial pressure is transmitted to extracranial via a liquid column and is then led to the measuring element. This method is accurate and permits reliable recording of the cerebral pulse curve or of the mean value for trend analysis.

Brain Neoplasms↗
PubMed1985

Polyacryl prosthesis for cranioplasty--their production in silicon rubber casts.

The frequently observed osteolysis after reimplantation of deep-frozen skullcap bone have led us to use polyacryl as the material of choice if a secondary covering of a skull bone defect becomes necessary. Polyacryl has an excellent biological compatibility but often yields unsatisfactory cosmetic results when the modelling is done at the site of the intervention, especially in the case of defects in the forehead region. A method is described that allows the preparation of a prosthesis before the actual operation identical with the original bone in every detail. The surgery is then confined to the anchoring of the prosthesis to the bone edges.

Acrylic Resins↗