Search PubMed⌕ Search

Biomedical subjects

W Hassler

Publications and source records attributed to W Hassler.

At least 73 records · Page 4Linked to original sources
PubMed1989

Cavernous angioma of the optic nerve. Case report.

The case of a 24-year-old woman with a cavernoma of the right optic nerve is presented. She suffered recurrent headaches and showed a deficit of the right nasal visual field. A computed tomography scan, a computed tomography cisternography, and magnetic resonance imaging revealed a lesion in projection on the right suprasellar cistern, yet angiography was inconspicuous. On operation, an angiomatous tumor of the right optic nerve with a surrounding hemorrhage was found. Histological examination of the specimen confirmed the intraoperative diagnosis of a cavernoma. Postoperatively, the right nasal visual field deficit increased slightly.

Adult↗
PubMed1989

Intramedullary cavernous angiomas.

Two cases of histologically verified intramedullary cavernous angiomas at C3 and D5-6 are presented. Both patients suffered progressive myelopathy with intermittent improvement. In both cases preoperative diagnosis was possible by means of magnetic resonance imaging using spin echo techniques, fast imaging, and phase display, while spinal angiography was not helpful. Laminectomy and total removal of the tumors were performed with temporary increased neurological deficits. It is thought that magnetic resonance imaging provides a useful diagnostic tool in these tumors and is also essential for planning surgical strategy.

Adult↗
PubMed1989

Hemodynamics of spinal dural arteriovenous fistulas. An intraoperative study.

Local hemodynamics were investigated during nine operations for spinal dural arteriovenous (AV) fistulas. In eight cases, microvascular Doppler sonography was used to measure flow velocities and vasomotor reactivity to CO2 changes. Intravascular pressure recordings of the draining veins on the medullary surface were performed in nine cases. The flow velocities in dural AV fistula feeding vessels were not as high as has been shown in cerebral angioma feeders. The AV fistula feeders often showed low end-diastolic flow velocities as a sign of increased vascular resistance, even in the presence of a downstream AV fistula, thus proving disturbance of venous outflow from the spinal canal. After excision of the fistula, the circulation of the spinal cord vessels improved, with higher inflow and outflow velocities. In the veins formerly draining the fistula, no further flow could be recorded; however, they did not collapse, indicating that some pressure remained. The mean venous pressure in the dural AV fistulas was about 74% of the systemic arterial pressure. It increased concomitantly with the arterial pressure, which may explain the clinical deterioration that occurs during physical activity. Fistulas with a high shunt volume on angiography showed only moderately increased venous pressures and a more pronounced pressure drop compared to low-volume fistulas. The CO2 reactivity of vessels supplying the spinal cord could be demonstrated in all cases, and was normal before and after removal of the fistula.

Aged↗
PubMed1989

Transcranial Doppler study of intracranial circulatory arrest.

To investigate the hemodynamics of intracranial circulatory arrest, the authors correlated the findings of noninvasive transcranial Doppler ultrasonography (TCD) with those of transfemoral four-vessel angiography in 65 patients following brain death and intracranial circulatory arrest due to severe intracranial hypertension. The three TCD stages of intracranial circulatory arrest, which have been described previously, corresponded with different levels of extracerebral angiographic cessation of flow. With TCD progression from the first stage (oscillating flow) to the third stage (no flow), the level where the dye stopped descended caudad from subarachnoid to cervical levels. The study shows that, in progressing intracranial hypertension, arterial circulatory standstill within the cranial cavity develops in a distal-to-proximal direction. The basal cerebral arteries remain patent in the early stages of intracranial circulatory arrest. Experimental evidence from the literature, together with the findings of the present investigation, points to the capillary bed as the initial site of the flow obstruction in progressing intracranial hypertension.

Adolescent↗
PubMed1989

Cavernous angiomas of the anterior visual pathways.

Three patients with cavernomas of the optic nerve, chiasm, or optic tract are presented. All suffered progressive visual loss due to local hemorrhage and the space-occupying effects of the vascular malformation. Computed tomography scans revealed small lesions with mild contrast enhancement in the suprasellar and parasellar cisterns, whereas angiography was unremarkable. Magnetic resonance imaging was helpful in our cases both for diagnosis and for planning surgical approach, showing typical signs of cavernomas as confirmed by subsequent surgery and histological examination. The clinical and intraoperative findings are presented.

Adolescent↗
PubMed1989

Pterional approach for surgical treatment of olfactory groove meningiomas.

We present our experience with the surgical treatment of olfactory groove meningiomas using a pterional approach. This approach provides the advantages of previous techniques, such as preserving the frontal brain and superior sagittal sinus, early devascularization of the tumor, and late dissection of tumor borders. Moreover, it also compensates for the shortcomings of other techniques, e.g., compression of frontal bridging veins, late dissection of dorsal tumor aspects involving vessels and optic nerves as well as facultative infection and cerebrospinal fluid fistula-related complications caused by opening of frontal sinuses. To date, 11 patients were treated in this way. As we encountered no surgical complications in our series we are encouraged to present our procedure.

Adult↗
PubMed1988

Ventricle puncture for external CSF drainage and pressure measurement using a modified puncture needle.

A modified needle for external ventricular drainage is presented. Contrary to conventional spinal needles with this instrument the sharp guide can be withdrawn after penetration of the dura, thus, no sharp instrument affects the brain, nor remains within the ventricles in cases of continuous drainage. Furthermore, depth of penetration can be determined preoperatively by means of a set screw also facilitating fixation of the needle. To date, we have used this modified needle in 50 patients for short or long term CSF drainage and for CSF pressure measurements. Trephination was performed with a hand or battery-driven drill. Except for an infection in one case we found no serious complications in our patients. In our opinion, ventricle puncture for external drainage and pressure measurement with this device is a simple and safe method and can be performed on the ward under local anaesthesia.

Adolescent↗
PubMed1988

Closed biopsy of the spine using a stereotactic biopsy forceps. Technical note.

A new technique for closed biopsy of the spine is presented. Using a stereotactic biopsy forceps, which is advanced to the lesion through a protective puncture cannula, sufficient samples from different sites of the lesion can be obtained. Biopsy was performed in seven patients harbouring osteolytic and osteoplastic lesions of the cervical (3 cases), thoracic (3 cases) and lumbar spine (1 case). Histological diagnosis was possible in five patients. In all of them, metastatic disease was found. In our opinion, using this device closed biopsy of the spine is a simple and efficient method for obtaining sufficient material at different levels of the spine and at different sites within a lesion. We recommend its use when the therapeutic consequences--surgical tumour removal with stabilization, stabilization alone or radiation therapy--is contingent on the histopathological diagnosis.

Aged↗
PubMed1988

The critical first minutes after subarachnoid hemorrhage.

Six patients were observed during recurrent subarachnoid hemorrhage (SAH). Three each had an open skull and intact dura mater and demonstrated an extreme increase in intracranial pressure (ICP) that developed within 1 minute and then declined over several minutes. Three other patients were investigated with transcranial Doppler sonography before, during, and after recurrent bleeding, and their hemodynamics were studied. There is conclusive evidence that acute spontaneous SAH is often followed by an intracranial circulatory arrest lasting for several minutes and caused by a peak of ICP in the range of mean arterial levels. The mechanisms involved are discussed. There are strong indications that this temporary intracranial circulatory arrest promotes hemostasis, but may constitute a severe ischemic event.

Female↗
PubMed1988

Transcranial Doppler ultrasonography in raised intracranial pressure and in intracranial circulatory arrest.

Transcranial Doppler ultrasonography was used to monitor 71 patients suffering from intracranial hypertension with subsequent brain death. Among these, 29 patients were also assessed for systemic arterial pressure and epidural intracranial pressure, so that a correlation between cerebral perfusion pressure and the Doppler ultrasonography waveforms could be established. Four-vessel angiography was also performed in 33 patients after clinical brain death. With increasing intracranial pressure, the transcranial Doppler ultrasonography waveforms exhibited different characteristic high-resistance profiles with first low, then zero, and then reversed diastolic flow velocities, depending on the relationship between intracranial pressure and blood pressure (that is, cerebral perfusion pressure). This study shows that transcranial Doppler ultrasonography may be used to assess the degree of intracranial hypertension. This technique further provides a practicable, noninvasive bedside monitor of therapeutic measures.

Adolescent↗
PubMed1987

Cerebral hemodynamics in angioma patients: an intraoperative study.

Local hemodynamics were investigated during 33 operations for cerebral arteriovenous malformation (AVM). In all cases, microvascular Doppler sonography was used to measure flow velocities and vasomotor reactivity to CO2 changes. Intravascular pressure recordings were performed in six patients. The AVM feeders had low intravascular pressure, high flow velocity, low peripheral stream resistance, and very poor vasomotor reactivity. Remote brain arteries showed no abnormalities. Doppler findings in arterial branches of AVM feeders that supplied normal brain indicated arteriolar dilation in their peripheral distribution. On removal of the angiomas, the arteries that formerly supplied them showed a return to normal intravascular pressure, whereas flow velocities dropped far below normal in these vessels. Remote arteries and branches of the former AVM feeders supplying the brain did not show any signs of impaired vasomotor reactivity following angioma removal. The results are in contrast to the normal perfusion pressure breakthrough theory.

Blood Flow Velocity↗
PubMed1986

[Neuroradiologic diagnosis and clinical aspects of giant intracranial aneurysms].

The CT and angiographic findings of 33 patients with intracranial giant aneurysms are reported. In the non-thrombosed giant aneurysms, CT showed a homogeneous, primarily hyperdense space-occupying lesion with strong enhancement. The partially thrombosed giant aneurysms appeared hyperdense with hypodense or isodense portions in the plain CT scan. The completely thrombosed giant aneurysms were isodense to hyperdense. In none of the 33 patients could perifocal edema be proved. A CT diagnosis was possible in every case of partially or non-thrombosed aneurysms. Pre-operative angiography in these cases was necessary only for purposes of vessel topography. Five completely thrombosed giant aneurysms could not be identified in either CT or the angiogram so that the diagnosis was not made until surgery. The clinical findings of these five cases of subarachnoid hemorrhage and 28 patients with signs of intracranial space-occupying lesions were diagnostically misleading, as they suggested an intracranial tumor.

Adult↗
PubMed1985

Possibilities and limits of the midline interhemispheric approach.

Based on experience in 17 children operated upon between 1978 and 1984, the possibilities and limitations of the interhemispheric parafalx approach to lesions of the anterior and posterior lateral ventricles and the third ventricle are described. The interhemispheric approach seems more advantageous than transcortical approaches since additional cortical and white matter lesions can be avoided. The limitations of visibility are the same as in transcortical approaches.

Adolescent↗
PubMed1985

Extradural and intradural microsurgical approaches to lesions of the optic canal and the superior orbital fissure.

Within 3 years, 34 patients with lesions of the posterior part of the orbit, the optic canal, and the superior orbital fissure were operated using different surgical approaches. The results on the functional and cosmetic outcomes were compiled. The pterional approach was shown to be the most useful one. It can be used in intradural as well as in extradural and combined operations. It allows an excellent view of basal cerebral structures as well as the frontal base of the skull. The operative results are dependent on the type and the location of the lesion, and, especially in meningiomas, on their relationship to the cavernous sinus.

Adult↗