[Changes of visual evoked potentials in experimental occlusion of superior sagittal sinus in the cat]. / Zmiany wzrokowych potencjalów wywolanych w eksperymentalnym zamknieciu zatoki strzalkowej górnej u kota.

In the model of experimental occlusion of superior sagittal sinus (SSS) in 6 cats, the authors examined cerebral cortex activity by means of visual evoked potentials (VEP). They found shortening of latency of P2 wave potential in relation to the control by 5.5-13.3 msec, appearing after 4-6 hours following occlusion. Simultaneous cerebrospinal fluid pressure measurement indicated an increase in pressure following SSS occlusion from the control medium value 6.8 mmHg to 12-13 mmHg. Visual cortex in cat (area 17) is situated along the posterior portion of SSS. The occlusion of this vessel results in local haemostasis, which is likely to affect the physico-chemical properties of visual cortex cells, especially in the slow conducting system X (X cells can be found exclusively in area 17). The partial disappearance of this system activity results in reducing the signal and noticeable shortening of latency to peak P2 wave of VEP.

[Relation between resorption resistance of cerebrospinal fluid and the degree of intracranial pressure]. / Zaleznosc oporu resorpcji plynu mózgowo-rdzeniowego od wysokosci cisnienia wewnatrzczaszkowego.

Changes in the CSF resorption resistance in relation to the value of the intracranial pressure have been assessed in 44 cats. Changes in the intracranial pressure have been produced with fluid infusions. Between 1 to 5 infusion tests with the rate 0.012-1.8 ml/min have been performed in each animal. A relationship between CSF resorption resistance and intracranial pressure has been found. With an increase in the intracranial pressure CSF resorption resistance increased to maximum value of 34 kPa/ml per minute (255.6 mm Hg/ml per minute) at pressure 2.96 +/- 0.69 kPa (22.2 +/- 5.2 mm Hg). At the intracranial pressure about 6.7 kPa (50 mm Hg) CSF resorption resistance rapidly decreased to the value of 13.9 kPa/ml per minute (104 mm Hg/ml per minute). Later, changes have been rather slight. It is possible, that the breaking point at 6.7 kPa corresponds to the mobilisation of all ways of CSF evacuation.

ICP dependent changes of CSF outflow resistance.

CSF outflow resistance was studied in cats using the lumbar infusion tests. Different infusion rates were applied from 0.012 to 1.8 ml/min. ICP level obtained during infusions varied from 8.9 +/- 3.0 to 144.0 +/- 25.7 mmHg. The calculated resistance (R) values were within 75.2 +/- 14.4 to 255.6 +/- 71.2. mm Hg/ml/min. The relation between ICP and R are characterized by a curve which can be divided into three parts. First R rises until an ICP level of about 20 mmHg is reached, then R decreases fast until the ICP value is about 50 mmHg, a further drop is much slower and the ICP/R curve becomes almost parallel to the ICP axis. The possible reasons for the ICP dependent changes of R as well as the clinical importance of the results obtained are discussed.

[Colloid cysts of the III ventricle. Report on our 8 cases operated on by the interhemispheric approach]. / Torbiel koloidowa komory III na podstawie 8 przypadków wlasnych operowanych z dojscia miedzypólkulowego.

Between 1984 and 1990, 12 patients with colloid cysts of the third ventricle were operated on. 8 of them underwent surgery by an anterior transcallosal approach with very good result. The authors discuss the different methods of surgical treatment using the microsurgical technique and present the advantages of the midline approach.

Intracranial volume reserve determination using CT images, numerical analysis and lumbar infusion tests. An experimental study.

The epidural balloon compression model in the cat was used in intracranial volume reserve studies. The evaluation of the intracranial volume-pressure relations was based on the lumbar infusion test data: intracranial pressure, CSF outflow resistance, volume-pressure response and on CT images numerical analysis (CTINA) values. Two methods were applied and compared in the study: lumbar infusion test and CT images numerical analysis. The determinations were performed at the balloon volumes of 0.5 ml, 1.0 ml, and 1.5 ml. First statistically significant changes were found at the balloon volume of 0.5 ml i.e. the increase of CSF outflow resistance and volume-pressure response (data obtained in lumbar infusion test) and the decrease in CTINA values. The rise of intracranial pressure was less informative as it was observed at the balloon volume of 1.5 ml. Therefore CTINA seems to be a very useful noninvasive screening method in clinical studies of intracranial volume reserve.

[Occlusion of the superior sagittal sinus caused by meningioma, intracranial volume-pressure relations and brain edema]. / Niedroznosc zatoki strzalkowej górnej spowodowana oponiakiem a wewnatrzczaszkowe stosunki objetosciowo-cisnieniowe i obrzek mózgu.

Fifty-one cases of parasagittal meningiomas were analysed. In 37 cases the tumour was situated in the middle and posterior part of the falx. In 17 cases occlusion of the superior sagittal sinus was diagnosed and confirmed by angiography. No correlation was found between the extent of brain oedema and sinus occlusion and tumour size. However, extensive oedema was present in tumours of high malignancy. Occlusion of the sagittal sinus caused no increase of intracranial pressure or venous stasis. This suggests that sinus occlusion caused by meningioma is completely compensated and has no effect on the preoperative and postoperative course.

Early pathomorphological changes and intracranial volume-pressure: relations following the experimental sagittal sinus occlusion.

Saggital sinus occlusion was produced in cats. The intracranial volume-pressure relations were studied using the lumbar infusion tests. Right after occlusion ICP rised from 7.1 +/- 1.8 to 12.4 +/- 4.1 mmHg. The values of outflow resistance and volume-pressure response increased also and remained significantly unchanged with only slight decrease of the volume-pressure response. The morphometric study of the surface veins showed the dilatation of the veins draining to the occluded saggital sinus for about 10-20%. No signs of the blood-brain barrier disruption were observed.