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Biomedical subjects

K Holl

Publications and source records attributed to K Holl.

At least 19 recordsLinked to original sources
PubMed2003

Recurrent cryptic vascular malformation associated with a developmental venous anomaly.

Abnormal venous drainage patterns, such as developmental venous anomalies (DVAs), are frequent findings neighbouring cryptic vascular malformations (CVMs). Although the clinical relevance of DVAs remains controversial, increasing attention has been focused on the possible importance of venous outflow disturbance and venous hypertension in DVAs for the development of CVMs. We present the case of a 32-year-old man with dysphasic seizures symptomatic for recurrence and rebleeding of a CVM of the left angulare gyrus, which drained entirely into a large DVA. A cavernoma had been surgically removed 1 year before, while the associated DVA had been left in place. In the following second surgical procedure, the new malformation, which was histologically verified as arteriovenous angioma (AVM), was removed and the DVA was occluded for the length of the angioma. Postoperative course of the patient was unremarkable, the patient is seizure free and neurologically intact. This first report of such a sequence of events raises important questions regarding the association of various vascular malformations, regarding transitional and hybrid forms, as well as the role of anomalous venous drainage in their pathophysiology and probably in their development. Our case and selected cases in literature suggest that venous hypertension in a DVA might not be just a coincidential finding, but sometimes can induce or influence the development and recurrence of associated vascular lesions. The developmental interrelationship, the potential mechanisms for this association and the implications of similar cases reported in pertinent literature are discussed.

Adult↗
PubMed2000

Advanced surgical approach for selective amygdalohippocampectomy through neuronavigation.

OBJECTIVE: Selective removal of the mesiobasal temporal structures through the transsylvian approach was introduced by Yasargil and Wieser in 1982. This alternative to standard temporal lobectomy provides excellent outcomes for seizure control. Basic actions in the transsylvian fissure exposure mainly serve to orient the surgeon, and they carry the risk of vasospasm and vessel damage. The aim of our study was to reduce landmark-guided surgery steps through neuronavigation. METHODS: During a 14-month period, 16 selective amygdalohippocampectomies were performed with the aid of the SMN (Carl Zeiss, Inc., Thornwood, NY) or StealthStation (Sofamor Danek, Memphis, TN) optically guided systems. We added safety procedures to the operation (including intraoperative rereferencing, obtaining additional bony reference points before craniotomy, performing a small craniotomy and making an accurate dural incision, and using contrast medium for vessel visualization) to develop a method that relies on navigational systems without further orientation by anatomic landmarks. RESULTS: Originally, performing an amygdalohippocampectomy required exposing the sylvian fissure from the carotid bifurcation to 2 cm beyond the middle cerebral artery bifurcation, which exposed one-third of the insula. By determining the entry point at the limen insulae and the target at the tip of the temporal horn, the mandatory extent of the opening to the sylvian fissure can be projected. Therefore, the exposure of the fissure can be limited to exactly the extent required for the transventricular approach through the uncinate fasciculus. CONCLUSION: Computer-assisted surgery is an effective tool in eliminating the exposure of anatomic landmarks in selective amygdalohippocampectomy. This modification combines the precision of targeting with minimal cortical and vessel traumatization.

Adult↗
PubMed1998

Microsurgical management of a complicated aneurysmal endovascular embolisation with GDC coil: a case report.

We present a case involving a microsurgical approach to solving the problem of a medial cerebral artery (MCA) occlusion occurring after GDC coiling of an internal cerebral artery (ICA) bifurcation aneurysm in a 40 year old woman. We describe the clinical course of the case and discuss technical possibilities and risks of clipping a coiled aneurysm. One key to success is awareness of changes in the aneurysm's properties after coiling. With loss of elasticity the aneurysm had the effect of a tumor fixed on the vessel. The apposition of the aneurysm to the wall of the vessel, as well as the aneurysm's rigidity and increase of intracranial pressure after subarachnoideal hemorrhage (SAH), may lead to occlusion of the vessel. In cases of an mandatory operation due to the occlusion of a main arterial stem after coiling, it is primarily crucial to perforate the aneurysm's fundus, remove the coils, and, finally, to clip the slack neck of the aneurysm. An attempt to precisely prepare and clip the aneurysmal neck without removing the coils could result in the rupture of the aneurysm's neck.

Adult↗
PubMed1996

A T1-weighted rapid three-dimensional gradient-echo technique (MP-RAGE) in preoperative MRI of intracranial tumours.

Our purpose was to determine the value of a T1-weighted rapid three-dimensional gradient-echo technique in preoperative MRI of brain tumours. We examined 30 patients with intracranial tumours who underwent neurosurgery, using T1-weighted magnetisation-prepared rapid gradient-echo (MP-RAGE) and axial T1-weighted spin-echo (SE) sequences, both before and after contrast medium (Gd-DTPA). Signal and contrast behaviour of anatomical and pathological structures were assessed with regions-of-interest (ROI) and visual inspection. Imaging results were compared with operative results. In 5 cases tumours and anatomical structures were segmented in MP-RAGE data sets. The MP-RAGE sequence considerably improved delineation of grey and white matter and small anatomical structures (vessels, cranial nerves), and significantly reduced flow artefacts. Contrast behaviour of tumours was similar with both techniques. Correlation of imaging with the operative results confirmed the reliability of the MP-RAGE sequence. Segmentation of MP-RAGE data sets allows three-dimensional display, which enables one to document the relevant information on a few images in selected cases.

Adolescent↗
PubMed1996

Effect of Xenon.

Explore the source record for details and available documents.

Acetazolamide↗
PubMed1996

[Stereotaxically guided versus ultrasound guided surgery--a comparative report of experiences].

Localisation and approach are the keys of surgery on brain tumours. Apart from the up and coming neuronavigational devices, stereotactical and ultrasound guidance are well established methods in locating intracranial tumours and in selecting the optimal approach for resection. Nevertheless it is not clear, which guidance tool is more practicable in the daily routine. Both methods have been used in our department since 1989. During the last six and half years we have operated on 1314 patients suffering from intracranial tumours. In 148 cases we have used either stereotactical (n = 37) or ultrasonic (n = 111) intraoperative guidance. The performing surgeon had documented ease of use, accuracy and users acceptance of the chosen guidance tool. The data were summarised together with the patients history and images in to a descriptive report. Since 1992 we noted a steady increase in guiding operations from 4% to 24%, mainly due to the more frequent use of ultrasound guidance. Saving time, easy handling, accuracy and plausible guidance with real time pictures have been the major advantages in favouring ultrasound guidance. Additionally, the freedom in choosing the appropriate approach seems to be essential. To achieve full advantage of all these benefits, experience and individual expertise are necessary. Conversely, the high accuracy of stereotactic guidance is not within the reach of the ultrasound, which is sufficient to guide the operation. According to our experiences, we recommend intraoperative ultrasound as an easy guiding tool. Except a few cases, this guiding tool seems to be superior to the stereotactic localisation of intracranial lesions.

Brain Mapping↗
PubMed1993

[Stable xenon computed tomography. Methodology and clinical application].

According to the principle of the dynamic computed tomography, stable xenon computed tomography allows measurement of the increase in density caused by xenon in the brain tissue. During a period of about 4 min a patient inhales a mixture of xenon (33%) and oxygen. By means of a special software, this method can be used to calculate flowmaps and to determine the local cerebral blood flow in a 1 cm x 1 cm areal. Stable xenon computed tomography is used mainly for cerebral blood flow measurements in patients with cerebrovascular diseases and also allows calculation of cerebral reserve capacity following stimulation of blood flow by the carboanhydrase inhibitor acetazolamide (Diamox).

Acetazolamide↗
PubMed1993

[Pneumatosis intestinalis--histology, immunocytochemistry and new theory of morphogenesis].

Based on the light microscopical and immunocytochemical findings in two cases of pneumatosis intestinalis, a new theory is advanced on the morphogenesis of the cysts that can be observed in this disease. The cavities identifiable in both cases in the submucosa of the small intestine and of the colon, respectively, were partially lined by histiocytes and foreign-body giant cells. Most of the lumina found in the subserosa of the stomach, small intestine and colon had an identical aspect. In addition, there were numerous true cysts here with a narrow, single-layered cells seam, showing the immunocytochemical characteristics of the mesothelium, but not the capillary endothelia. Thus, contrary to previous assumptions, pneumatosis interstinalis apparently does not develop from cystic dilatation of gas-filled lymph vessels that shrink and disappear in the process of an inflammatory foreign body reaction. Rather, the disease initially seems to manifest itself through gas-filled pseudocysts partially bordered by histiocytes and foreign-body giant cells, which become secondarily mesothelialized in the subserosa. Lymph vessels would thus not have significance for the morphogenesis of this disease.

Aged↗
PubMed1992

Immunocytochemistry in adrenocortical tumours: a clinicomorphological study of 72 neoplasms.

Surgical specimens of 72 adrenocortical tumours (ACTs) were investigated. Histologically, 57 tumours were classified as adenomas and 15 as carcinomas. In 9 of the latter cases, distant metastases and/or lethal outcome of disease was recorded. Immunocyto-chemistry showed only 2 ACTs to be positive for cytokeratin and 6 for vimentin. None of the 72 tumours showed argyrophilia or immunoreactivity for epithelial membrane antigen (EMA), S-100 protein, chromogranin A, Leu 7 or Leu-M1, while 31 cases exhibited positivity on immunostaining with a polyclonal antiserum against synaptophysin. All 72 ACTs were immunoreactive with the recently described antibody D11. Thus the panel of antibodies described here could not discriminate between adenomas and carcinomas or between carcinomas with aggressive and indolent behaviour. Immunostaining with D11 and for EMA and Leu-M1 may help to distinguish ACTs from phenotypically similar lesions of different histogenesis.

Adrenal Cortex Neoplasms↗
PubMed1992

Pathology of multiple endocrine neoplasias 2A and 2B: a review.

This review describes recent findings on the morphology, function and prognosis of lesions associated with the MEN 2 syndromes. Special emphasis is placed on the analogies and discrepancies between the hereditary and nonhereditary manifestations of the endocrine proliferations involved.

Adrenal Gland Neoplasms↗
PubMed1991

DNA cytophotometry in adrenocortical tumours: a clinicomorphological study of 66 cases.

Surgical specimens of 66 adrenocortical tumours were investigated by conventional microscopy and DNA cytophotometry. Histologically, 50 neoplasms were classified as adenomas and 16 as carcinomas. In only 8 of the latter cases were distant metastases and/or a lethal outcome recorded. On single cell scanning cytophotometry either non-euploid or aneuploid DNA histograms were identified in 24 of 50 adenomas (48%) and in 14 of 16 carcinomas (88%). The two carcinomas exhibiting euploid DNA distributions fell into the group of 7 malignancies which are recurrence-free so far. From these findings it is concluded that DNA measurements have no diagnostic and only limited prognostic value in neoplasms of the adrenal cortex.

Adenoma↗
PubMed1991

Effects of 33% stable xenon/O2 mixture on somatosensory evoked potentials.

The influences of 30% stable xenon/O2 mixture on somatosensory evoked potentials were investigated in 8 patients with and without Diamox application. Changes of the amplitude of the primary cortical response occurred frequently and correlated well with the psychotropical effect of xenon. They usually normalized within 2 to 3 minutes after ending xenon inhalation. There were no significant changes of the latency of the N20.

Drug Stability↗
PubMed1991

Immunocytochemistry of paragangliomas--value of staining for S-100 protein and glial fibrillary acid protein in diagnosis and prognosis.

Surgical specimens of 65 adrenal and 27 extra-adrenal paragangliomas, the latter comprising 11 carotid body, five jugulotympanic, one aorticopulmonary, eight aorticosympathetic and two visceral autonomic tumours, were examined immunocytochemically for the presence of glial fibrillary acid protein (GFAP) and S-100 protein. Six adrenal and four extra-adrenal (one parasympathetic and three sympathetic) neoplasms pursued a malignant clinical course. S-100 staining of sustentacular (type 2) cells was seen in both adrenal (48/65) and extra-adrenal (23/27) lesions, the 10 malignant tumours being entirely devoid of S-100 protein positive cells. GFAP positivity of type 2 cells was seen in only 16 of the extra-adrenal tumours, all of these lesions belonging to the group of benign parasympathetic paragangliomas. The presence of S-100 positive type 2 cells may thus help to exclude malignancy in individual paraganglioma cases, while GFAP positivity of such cells renders possible the correct typing of benign parasympathetic paragangliomas.

Adrenal Gland Neoplasms↗
PubMed1990

[The effect of acetazolamide-induced, endogenous volume stress of the cerebrospinal system on intracranial pressure. Diamox--effect on intracranial pressure].

In 16 patients with possible disturbed CSF circulation longterm recording of intracranial pressure (ICP) was performed. In 9 of the 16 patients the disorder became evident after the application of an exogenous volume-pressure testing procedure. This procedure enabled a classification into a group I--disturbed CSF circulation (8 patients)--and another group II--normal CSF circulation (8 patients). During a routine Xenon-CT-CBF study all patients of both groups were given to 1 g acetazolamide (DIAMOX) intravenously. Before, during and after the administration of DIAMOX the epidural ICP was continuously measured. An increase in ICP was monitored in all patients. In group I the average initial ICP was 13.6 +/- 7.6 mmHg. The maximum ICP was reached within a time interval of 13.1 +/- 4.5 min after DIAMOX administration. At this time the mean ICP was 36.4 +/- 19.2 mmHg (p less than 0.01). The average initial ICP in group II was 6.3 +/- 4.2 mmHg. The maximum ICP was reached within a time interval of 13.6 +/- 1.1 min. At this time the mean ICP was 11.9 +/- 4.8 mmHg (p less than 0.01). In respect to the maximum ICP both groups were significantly different (p less than 0.01). Despite a considerably rising ICP up to values of about 50 to 70 mmHg in several patients of group I only 1 patient complained of being sick. Presumingly, an ICP elevation caused by vasodilatation would be better tolerated than ICP elevations due to other causes.

Acetazolamide↗