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Biomedical subjects

P Grunert

Publications and source records attributed to P Grunert.

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

Stereotactically guided cavernous malformation surgery.

The incidence of a significant hemorrhage in the natural history of cavernomas is below 1% per year, but the risk of a second hemorrhage in patients with initial bleeding cavernomas is between 14% and 29%. In the light of these figures, all cavernomas ought to be resected if surgical-related morbidity can be minimized. Stereotactically guided neurosurgery offers the advantage of planning the least traumatic approach before craniotomy due to the knowledge of the exact localisation of the lesion. During a 2-year period 12 patients (age 16-54 years) with intracranial supratentorial cavernomas (size 0.5-1.8 cm) were treated by stereotactically guided microsurgery. The cavernomas were seated in a depth between 0.4 and 4.5 cm. 4 patients had an overt hemorrhage in their history. In six cases a seizure was the first symptom (altogether 8 patients had seizures preoperatively). Two patients were asymptomatic. Standard CRW (Cosman, Roberts, Wells) stereotactic system was used in all cases. The skin incision and the osteoplastic craniotomy (mean diameter 2.8 cm) were planned stereotactically. In 11 patients a transsulcal approach was used. The size of the corticotomy could be limited to less than 1 cm. Using the stereotactic method, all cavernomas were found with a high degree of accuracy. After lesionectomy a total of 1 to 2 mm of the surrounding yellow-stained brain tissue was sucked away because it contains hemosiderin and therefore iron, which may have an epileptogenic effect. No relevant surgical-related neurological morbidity was found in any patient a half year after surgery. Seven out of eight patients were free of seizures. One still had problems.

Adolescent↗
PubMed1996

Species specific immunoassays to measure blood platelet and coagulation activation in the rat.

The purpose of this study was to develop specific and sensitive immunoassays to detect early indices of hypercoagulability in the rat. Rat platelet factor 4 (rPF4) and rat fibrinopeptide A (rFPA) assays, tools for the detection of activation of platelets and coagulation respectively, were designed using antibodies raised against purified rPF4 and against synthetic rFPA. The relevance of these new assays and of the commercially available ELISA kit for thrombin-antithrombin III (TAT) complexes was demonstrated in a rat model of a prethrombotic state induced by intravenous infusion of varying doses of thrombo-plastin (90 to 2400 microliters/kg/h). In this model, the immunoassays allowed simultaneous detection of low levels of rFPA and rPF4 which were correlated with fibrinogen and platelet consumption and TAT generation and further proved to be of higher sensitivity than the classical methods of platelet count or measurement of fibrinogen levels. Plasma concentrations of rFPA, rPF4 and TAT were dependent on infusion time and thromboplastin dose, while hirudin (1 mg/kg) prevented their appearance. Thus the new specific immunoassays for rPF4 and rFPA and the commercial human TAT assay represent useful tools for pathophysiological studies or the screening of antithrombotic drugs in rats.

Animals↗
PubMed1995

The need for adjunctive focused radiation therapy in pituitary adenomas.

In pituitary adenomas radiation therapy regardless of the technique should be limited to surgical failures. The delayed onset of beneficial effects and the high rate of pituitary insufficiency have to be weighed against the good surgical and/or medical results in the treatment of these tumours. Unfortunately surgical outcome is almost invariably correlated with invasive growth. Invasiveness is statistically significantly correlated with tumour size, as well as with high proliferation rates, which can be measured by immunohistological methods such as mAB KI-67. Owing to the good results of medical treatment, radiation therapy is usually unnecessary in prolactinomas. Patients with persistent hypersecretion of growth hormone after unsuccessful surgery may represent the ideal candidates for radiation therapy, whereas patients with persistent Cushing's disease need cure for hypercortisolism without delay. In patients with residual tumour due to non functioning adenomas, radiation therapy should only be given if the proliferation rate is high.

Adenoma↗
PubMed1995

Target point calculation in the computerized tomography. Comparison of different stereotactic methods.

The adaptation of computerized tomography for stereotactic operations requires the transformation of the coordinates of the target point from the CT image space into the stereotactic frame space. Two basic solutions for this transformation are realized in the most of the contemporary stereotactical systems. The indirect geometric method adjusts the frame coordinate system mechanically and identifies its origin in the CT image. There are 6 degrees of freedom: 3 of rotation and 3 of translation which have to be taken into consideration. The second method is a based on direct algebraic coordinate transformation and is independent of the explicite knowledge of the relationship between the image and the frame space. A localization frame serves to determine a transformation matrix which, applied to any point in the image, transforms the coordinates directly into the frame coordinate system. Only the algebraic method is independent of the position of the patient in the gantry. All other methods require high mechanical precision of the alignment and stability for the CT table.

Brain Diseases↗
PubMed1994

Results of 200 intracranial stereotactic biopsies.

200 stereotactic biopsies were evaluated. The validity of the intraoperative histopathological results were compared with the final diagnosis using conventional embedding and staining techniques. Further comparison between the histology of the biopsy and the post mortem or open operative findings were possible in 41 cases. Discrepancy was found in one case regarding the tumor detection, and in three cases regarding the tumor grading. The mortality in our patients was 1% and the morbidity 3%. Stereotactical biopsy had a low risk even in deep brain regions such as basal ganglia, mesencephalon, and pons. At the same time the high histologic validity makes the CT-guided stereotactical biopsy recommendable in all lesions not operated by an open resection before any conservative or palliative therapy is started.

Adolescent↗
PubMed1994

Endoscopic procedures through the foramen interventriculare of Monro under stereotactical conditions.

The foramen interventriculare of Monro is an anatomical narrowness for the endoscopic access to the third ventricle. The effective mechanical angle to pass the foramen interventriculare from a frontal bore hole depends on the diameter in the plane of entrance, the depth of the foramen, and the diameter of the endoscope. Under the pathological conditions of a hydrocephalus internus the foramen interventriculare is enlarged. By means of stereotactical guidance, it is possible to reach the third ventricle accurately without damaging anatomical structures around the foramen interventriculare. The endoscopic technique under stereotactical guidance using a rigid endoscope is sufficient and safe to perform ventriculostomies in cases of hydrocephalus occlusus. Best clinical results were obtained in patients with benign aqueduct stenosis or with a tumor in this region compressing the aqueduct. In all patients no further shunt operation was necessary. The path through the foramen interventriculare should be considered also for biopsies in the third ventricle. Calculation of the foramen interventriculare trajectory prevents perforation of the roof of the third ventricle containing the main deep veins. Lesions in the foramen interventriculare like colloid cysts can also be approached very accurately by means of stereotactical calculation. However the endoscopic technique with the at present obtainable instruments does not allow removal of the whole lesion. Even so a free passage to the third ventricle can be achieved by reducing the size of the cyst by means of coagulation and sucking off the colloid material.

Adolescent↗
PubMed1992

CT-guided stereotactic biopsy aided by Doppler ultrasonic vascular monitoring.

The use of a 20 MHz pulsed Doppler technique during stereotactic brain tumour biopsies is described. By means of a miniaturized ultrasonic probe the tissue planned for biopsy was investigated for vessel signals. Out of 41 patients, with this technique a flow-pulse curve in front of the biopsy cannula was registered in 14 cases. In 9 cases one pulse curve was determined and in 5 cases two or more flow curves were found, indicating the presence of arterial vessels. The depth of the vessels signal could be localized and this area avoided for biopsy sampling. In a series of 41 stereotactic biopsies carried out in this way there was no intra-operative haemorrhage or postoperative haematoma.

Adolescent↗
PubMed1991

A new device for interstitial 125Iodine seed implantation.

A new device for interstitial implantation of I125 seeds is presented. The technical details and function of the system are described and compared with well-known commercial systems. Its unique design allows for simple, fast, and safe treatment of most tumor sites including stereotactic implantation of brain. Radiation measurements indicate low exposure to both patients and personnel during implantation.

Brachytherapy↗
PubMed1990

Surgical treatment of epilepsy.

Seventy patients with intractable epilepsy were surgically treated. Thirty-three patients underwent a stereotactic procedure and in all as a first-stage operation fornicotomy was performed. Because of inadequate results in 14 patients, an additional stereotactic intervention was necessary; the targets were amygdala, thalamus, and Forel's H-field, and the final outcome of these patients was 9 (27%) seizure-free, 19 (58%) improved, and 5 (15%) unchanged. In 3 patients a selective amygdalo-hippocampectomy was performed with 2 seizure-free patients and one with improvement. Topectomy in focal epilepsy in 5 patients resulted in freedom from seizures in all cases. In 23 patients a lobectomy was performed; 10 (43%) were seizures-free, 8 (35%) were improved, and 5 (22%) were unchanged. In 6 patients only a pathological lesion was resected. Our results speak in favour of ablative surgery. However, stereotactic operations are indicated in cases with secondary generalization and dissipated foci on the dominant hemisphere.

Adult↗
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↗
PubMed1989

[Stereotaxic biopsy of intracranial processes: validity of histologic diagnosis].

The diagnostic validity of stereotactic intracranial biopsies was investigated in 70 patients retrospectively. In 56 cases (80%) the presence of a neoplastic lesion as well as its grade of malignancy was proved by cytological, histological and immunohistochemical techniques. An inflammatory or vascular lesion was found in 8 patients (11.4%). In 6 patients (8.6%) the nature of the lesion remained unclear because of nonspecific histological findings. In 27 cases a correlation was found between the biopsy specimens and corresponding material obtained during open surgery or autopsy. 24 concordant results were found (88.9%). In one case a malignant tumour was classified only according to the findings obtained at operation. In two cases subsequently diagnosed as glioblastoma biopsy reported a higher differentiated astrocytoma and a non-neoplastic lesion, respectively. These results confirm stereotactic biopsy of intracranial lesions as a method with low complication rate and high diagnostic validity.

Astrocytoma↗
PubMed1989

[Therapy refractory pain of malignant origin].

In 50 patients with intractable pain due to malignancy an intrathecal application of morphine was performed. The follow-up extended in 28 patients till their death. Overall 46% of the patients had a profit of the therapy for the whole remaining life, 25% at least half of it. The main indication to intrathecal infusion of morphine is in multiloculare and midline pain especially in advanced cancer stage.

Adult↗
PubMed1988

[Results of electrocoagulation of Gasser's ganglion in 250 patients with idiopathic trigeminal neuralgia].

In 250 patients with tic doulourex an percutaneous radiofrequency coagulation of the gasserian ganglion has been performed. In 92.2% of the cases the patients were post-operatively painfree. The follow-up extended in 122 cases over 7 years. In these patients a pain recurrency was noted in 27%. On behalf of low invasivity of the procedure the radio-frequency coagulation of the gasserian ganglion is a recommendable operation with low risk and high efficiency especially in old patients.

Adult↗
PubMed1987

[Stereotaxic biopsy of brain tumors].

The management of patients with a brain tumour is essentially dependent on the knowledge of the histology. Because of its high accuracy and low complication rate stereotactic tumour biopsy has proven to be an important diagnostic procedure, especially in deep-seated lesions. Stereotactic tumour biopsy was carried out in 18 patients with target calculation either from computerized tomography (CT) or magnetic resonance imaging (MR).

Adult↗
PubMed1986

[Partial vertical nucleotomy as a modification of tractotomy of the trigeminal nerve].

The authors report on partial vertical nucleotomy, a modification of tractotomy of the quintothalamic tract. In 1979 eight patients underwent this procedure. Three of them showed a recurrence of pain from genuine trigeminal neuralgia. Three patients had symptomatic trigeminal neuralgia, one patient atypical neuralgia of the face without organic cause, whereas in one case the neuralgia occurred subsequent to a herpes zoster. At the time of examination all patients were free from pain.

Facial Pain↗
PubMed1986

[Cerebral seizure following lumbar myelography with iopamidol].

This is a report of a case of a serious side effect following lumbar radiculography with the water soluble contrast medium Iopamidol. The complication consisted of a generalized seizure after an episode of myoclonic jerking of the legs. This was the first complication in a series of 1070 lumbar and cervical myelograms with this medium.

Adult↗