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Biomedical subjects

E Knosp

Publications and source records attributed to E Knosp.

At least 37 records · Page 2Linked to original sources

Meningiomas of the space of the cavernous sinus.

During the years 1985 to 1992, we encountered 59 patients with meningiomas involving the space of the cavernous sinus. In 29 of these patients, meningiomas were primarily located within the space of the cavernous sinus and were operated on without mortality and with low morbidity. A small subtemporal surgical approach was favored, which allowed initial tumor resection from the posterior aspect, where the Parkinson's triangle is wide, thus avoiding the additional morbidity of large-scale approaches. According to the relationships of the all-important cranial nerves passing within the lateral wall of the cavernous sinus, we divided the primary intracavernous meningiomas into four types, which reflected not only the preoperative cranial nerve deficit but also the feasibility of surgical resection. Cranial nerve function deteriorated after operations in 14% of oculomotor nerves, in one abducent nerve, in 58% of trochlear nerves, and in 21% of trigeminal nerves. We encountered improvement of function in 43% of oculomotor nerves, in 50% of abducent nerves, and in approximately 30% of the second and third but in only 7% of the first branches of trigeminal nerves. There was no improvement in trochlear nerve function. Improvement of oculomotor nerve function was observed only in moderately impaired nerves, which indicates that surgery should be undertaken early to preserve or improve oculomotor nerve function.

Cavernous Sinus↗

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↗

MR-appearance of the pituitary gland before and after resection of pituitary macroadenomas.

Pituitary macroadenomas can cause severe compression and displacement of the pituitary gland. This study was undertaken to determine the value of contrast administration for the detection of the pituitary gland in patients with pituitary macroadenomas, to evaluate the preoperative location and configuration of the pituitary gland and to describe its postoperative changes after tumour resection. Preoperative and postoperative MR imaging examinations of 30 patients with histologically proven pituitary macroadenomas were retrospectively evaluated. The examinations were performed on a 1.5 T unit, by obtaining T1-weighted sagittal and coronal images after administration of gadopentetate dimeglumine. On preoperative MR images, contrast administration increased the detectability of the anterior lobe from 30% to 80%. Depending on the size and extension of the adenoma, the pituitary gland was displaced to the suprasellar space (53%) and/or deformed to a club-shaped (27%) or sickle-shaped (47%) configuration. In six patients, the sickle-shaped pituitary gland was interposed between the cavernous sinus and the adenoma ('rim-sign'), which was seen only on gadopentetate dimeglumine-enhanced images. In these cases, there was no infiltration of the cavernous sinus at surgery. Postoperatively, descent of the pituitary gland was found in 63%, and reexpansion in 54%. We conclude that contrast administration improves the detectability of the pituitary gland on preoperative MR images, and that the displacement and deformation of the pituitary gland depend on the size, location and extension of the adenoma. Preoperatively, demonstration of the pituitary gland interposed between the cavernous sinus and the adenoma ('rim-sign') is a very useful sign for exclusion of cavernous sinus infiltration, best seen on contrast-enhanced coronal MR images. The normal postoperative changes of the pituitary gland after tumour resection include repositioning and re-expansion.

Adenoma↗

Pituitary adenomas with invasion of the cavernous sinus space: a magnetic resonance imaging classification compared with surgical findings.

We present 25 pituitary adenomas that were confirmed surgically to have invaded the cavernous sinus space. The surgical results are compared with the preoperative magnetic resonance imaging findings. For comparable radiological criteria, we classified parasellar growth into five grades. This proposed classification is based on coronal sections of unenhanced and gadolinium diethylene-triamine-pentaacetic acid enhanced magnetic resonance imaging scans, with the readily detectable internal carotid artery serving as the radiological landmark. The anatomical, radiological, and surgical conditions of each grade are considered. Grades 0, 1, 2, and 3 are distinguished from each other by a medial tangent, the intercarotid line--through the cross-sectional centers--and a lateral tangent on the intra- and supracavernous internal carotid arteries. Grade 0 represents the normal condition, and Grade 4 corresponds to the total encasement of the intracavernous carotid artery. According to this classification, surgically proven invasion of the cavernous sinus space was present in all Grade 4 and Grade 3 cases and in all but one of the Grade 2 cases; no invasion was present in Grade 0 and Grade 1 cases. Therefore, the critical area where invasion of the cavernous sinus space becomes very likely and can be proven surgically is located between the intercarotid line and the lateral tangent, which is represented by our Grade 2. We also measured tumor growth rates, using the monoclonal antibody KI-67, which shows a statistically higher proliferation rate (P < 0.001) in adenomas with surgically observed invasion into the cavernous sinus space, as compared with noninvasive adenomas.

Adenoma↗

The termination of the vein of "Labbé" and its microsurgical significance.

Information about the termination of the inferior anastomotic vein of Labbé is of crucial importance in the subtemporal neurosurgical approach and its modifications. An intradural course has been observed in all cases. The vein of Labbé reaches in 3/4th the anterior third of the transverse sinus, in 73% of all cases tracing a so-called tentorial sinus. By dissecting the vein of Labbé out of its dural bed and shifting its fixation point, microsurgical access is facilitated considerably.

Cerebral Veins↗

Pituitary adenomas: findings of postoperative MR imaging.

Preoperative and postoperative magnetic resonance (MR) images obtained in 25 patients with pituitary macroadenomas (1.1-5.2 cm in diameter) were evaluated to determine normal (physiologic) and abnormal findings after transsphenoidal or subfrontal surgery. With a 1.5-T unit, T1-weighted sagittal and coronal images were obtained before and after administration of gadopentetate dimeglumine. The physiologic changes after surgery included resorption of packing material and sphenoid sinus opacifications, reexpansion of the pituitary gland, and lowering of the optic chiasm. Implanted gelatin foam appeared as an endosellar, circularly enhancing mass that was seen on follow-up studies to have decreased in size. Muscle-and-fat implants appeared as areas of high signal intensity. In 14 patients, residual tumors were found in the suprasellar (n = 4), retrosellar (n = 3), parasellar (n = 8), and/or endosellar (n = 3) space. Residual tumors were differentiated from implant materials by means of location, characteristic signal intensity, and enhancing pattern, which were identical to those of the corresponding preoperative adenoma in 13 cases (93%). Preoperative studies and clinical information are helpful in the evaluation of postoperative MR imaging examinations.

Adenoma↗

[Treatment of prolactinoma with a new dopamine agonist].

Eleven patients (6 men, 5 women, mean age 42 [25-65] years) with prolactinomas were treated for 4-16 months with a new dopamine agonist (CV 205-502), at a daily dose of between 0.075 and 0.45 mg. All patients had previously undergone surgery and/or been treated with bromocriptine or lisuride, but had not tolerated this therapy well, and/or had not shown sufficient suppression of serum prolactin levels. Baseline prolactin levels were between 149 and 4120 ng/ml. During treatment, levels fell significantly in all patients, to between 2.0 and 683 ng/ml, and to within the reference range in five patients. In seven patients, the adenoma size decreased by 10 to greater than 50%. Adverse reactions were less frequent and less marked than with the prior therapy. The new dopamine agonist is an alternative treatment for prolactinomas where other therapies have been unsuccessful.

Adult↗

Proliferation in pituitary adenomas: measurement by MAb KI 67.

The monoclonal antibody MAb KI 67 reacts with a nuclear antigen throughout the entire cell cycle and allows easy evaluation of proliferating tumour cells on routinely prepared smear and frozen sections. 120 pituitary adenomas were investigated by use of the monoclonal antibody KI 67 in a two-step avidin-biotin-peroxidase complex (ABC) technique. The KI 67 labelling index (LI) ranged in all adenomas from 0.2 to 4.6%. In 90 cases of transphenoidally operated adenomas the dura of the sella floor was investigated histologically. Adenomas with histologically proven dural infiltration showed a statistically significant higher KI 67 LI (p less than 0.001) compared to non-invasive adenomas.

Adenoma↗

Pituitary adenomas with parasellar invasion.

Pituitary adenomas with extension into the parasellar space, the so called "cavernous sinus" can be demonstrated best using MRI. To improve the delineation from the venous compartments the use of unenhanced and enhanced MRI scans is essential. In 25 pituitary adenomas with surgically proven infiltration into the space of the cavernous sinus we correlated the MRI findings with our surgical observations. When the adenoma encases the intracavernous internal carotid artery or reaches as far as to the lateral aspect of the artery, invasion was present in all cases. The critical area where invasion could not be predicted from MRI is the distance between the medial and the lateral aspect of the intracavernous internal carotid artery. By measurement with the monoclonal antibody KI-67 it could be shown, that pituitary adenomas infiltrating the parasellar space have a statistically significant higher growth rate (p less than 0.001), compared to non-invasive adenomas. This is of special interest, because surgical cure becomes unlikely, when invasion into the space of the cavernous sinus is present.

Adenoma↗

Modifications of temporal approaches: anatomical aspects of a microneurosurgical approach.

All subtemporal approaches have in common the risk of temporal lobe damage. To reduce the retraction of the temporal lobe we combine two synergistic modifications of temporal approaches to reach the prepontine space. The first is the temporary resection of the zygomatic arch which allows to bring the temporalis muscle more caudally and subsequently allows an anterior subtemporal approach with only minimal temporal lobe retraction. The second modification is the resection of the apex of the petrous bone after incision of the tentorium. This provides an excellent view into the posterior fossa between the trigeminal nerve medially, the internal carotid artery caudally and the internal auditory canal laterally. The anatomical aspects of a microneurosurgical approach regarding these modifications are reported and discussed.

Brain Neoplasms↗

[Rhinocerebral mycoses caused by Mucoraceae species (mucormycosis). Case report and literature review].

According to the literature and on the basis of the case reported in this paper of rhinocerebral mucoraceae mycosis we summarize the characteristic features as follows: mucoraceae--mycoses--common, but wrong term: "mucormycoses"--are a group of infections caused by members of the family mucoraceae (Mucor, Rhizomucor, Rhizopus, Absidia species)--most frequently by Rhizopus species. Primarily the fungi enter the pharynx or nose, local infections or trauma being a prerequisite. The most important predisposing factor is diabetes mellitus. Invading the tissue and causing vascular thrombosis the infection frequently takes an acute, often fulminating and fatal course. Acute sinusitis accompanied by swelling of the cheek and protrusion of the eye in a diabetic, particularly with acidosis, are pathognomonic. Diagnosis is confirmed by microscopic examination of infected tissue (unstained smear or histologically). Since systemically administered antifungals have not proved very effective in these myoses, mainly because an adequate tissue level can hardly be achieved, the most effective and curative treatment is surgical removal of infected tissue, simultaneous control of diabetes being mandatory.

Antifungal Agents↗

[Gd-DTPA in the MR diagnosis of pituitary adenomas].

25 patients with surgically (n = 14) and/or biochemically (n = 20) confirmed pituitary adenomas were examined on a 1.5 T superconducting MR system by means of multislice spin-echo technique, 3 mm thick sections and a 256 x 256 matrix. T1-weighted sagittal and coronal sections were obtained before and after administration of Gd-DTPA (0.1 mmol./kg. BW). 13 microadenomas and 12 macroadenomas were found. In unenhanced T1-weighted images 48% of the adenomas were isointense, 48% were hypointense and 4% were hyperintense. 58% of the adenomas enhanced to a lesser degree, 15% enhanced to a higher degree than the normal pituitary gland. 12% showed equal enhancement and 15% showed hypointense and hyperintense areas simultaneously. In 3 patients (12%) there was evidence of adenoma only in the enhanced images. The delineation of the adenoma from the cavernous sinus was possible in 95% of the enhanced, but only in 25% of the native scans.

Adenoma↗

Gd-DTPA enhanced high resolution MR imaging of pituitary adenomas.

Thirty-eight patients with surgically or biochemically confirmed pituitary adenomas were examined on a 1.5 T MRI system by means of spin echo technique with 3 mm slice thickness. T1 weighted sagittal and coronal sections were obtained before and after the administration of Gd-DTPA. Compared with the normal pituitary anterior lobe, 8% of the adenomas were hyperintense, 45% were isointense, 42% were hypointense and 5% were inhomogeneously intense. After Gd-DTPA administration, 13% enhanced to a greater degree, 10% to the same, and 57% to a lesser degree than the normal pituitary tissue. Twenty percent showed inhomogeneous enhancement. In 10%, there was evidence of adenoma only in the enhanced images. The delineation of the adenoma from the cavernous sinus was improved from 47% in unenhanced scans to 91% after Gd-DTPA administration.

Adenoma↗

Proliferation activity in pituitary adenomas: measurement by monoclonal antibody Ki-67.

The monoclonal antibody (MAb) Ki-67 detects a nuclear antigen expressed by proliferating cells during the entire cell cycle. In contrast to conventional histological techniques, the use of MAb Ki-67 on frozen sections or cytological smear preparations allows direct determination of the growth rate of tumors routinely. Sixty-two pituitary adenomas were investigated by use of the MAb Ki-67 in a two-step avidin-biotin-peroxidase complex technique. The proliferation activity ranged from 0.1 to 2.8%. There was no significant difference between the proliferation and hormonal state of the adenomas. Adenomas for which there was histological evidence of dural infiltration, however, showed a statistically significant higher proliferation activity (P less than 0.05) compared to noninvasive adenomas.

Adenoma↗

[Immunologic hormone detection in hypophyseal adenomas: correlation of serum hormone findings with immunocytochemical hormone levels in tumor tissue].

Forty-four out of 82 patients with neurosurgically removed pituitary adenomas showed preoperatively elevated plasma hormone levels of prolactin (PRL; 22 patients), of human growth hormone (hGH; 15 patients), and of adrenocorticotropic hormone (ACTH; 7 patients). Immunocytochemical detection of the hypersecreted hormone in paraffin sections of tumour tissue, was possible in all 7 patients (100%) with Cushing's disease, in 20 patients (90%) with hyperprolactinaemia, and in 10 patients (66%) with acromegaly. In a further 3 cases beta-TSH, in one case beta-LH, and in 8 cases alpha-HCG were demonstrated in sections of tumour tissue. No clinical evidence of endocrine disturbance was found in any of these latter cases. More than one anterior pituitary hormone was detected in sections of tumour tissue in 7 cases. An overall qualitative correlation of 85% was found between the elevated plasma hormone level and immunocytochemical hormone detection in tumour tissue sections. Since there is no correlation between conventional histological staining modalities (acidophilic, basophilic, chromophobic) on the one hand, and the level of plasma hormones or immunological hormone detection in tumour tissue on the other hand, modern histological diagnosis of a pituitary adenoma should include assessment of the functional state as found by immunocytochemical hormone determination.

Adenoma↗

Cavernous sinus surgery. Approach through the lateral wall.

The cavernous sinus is divided from the surgical point of view into three parts. The middle part consists of the lateral sinus wall, the cranial nerves III, IV, V, VI and the posterior siphonknee of the internal carotid artery. Lesions of this region, vascular as well as tumorous, can be exposed by approaching the lateral sinus wall. The surgical dissection through the sinus wall is based on some important anatomical details, which are described here. As a consequence a modified transcavernous approach will be introduced and demonstrated by 35 clinical cases.

Aged↗

The paraclinoid carotid artery: anatomical aspects of a microneurosurgical approach.

The paraclinoid area is investigated anatomically for possible microneurosurgical approaches to the C3 segment of the internal carotid artery and to structures in the vicinity of the anterior siphon knee. Removal of the anterior clinoid process reveals a tight connective tissue ring that fixes the internal carotid artery to the surrounding osseous structures at the point of its transdural passage. Transection of this fibrous ring opens a microsurgical pathway to the carotid C3 segment. The artery is surrounded by a loose connective tissue layer that allows blunt preparation along the C3 segment, without compromising the cranial nerves and without damaging venous compartments of the cavernous sinus. This approach provides neurosurgical access to paraclinoidal aneurysms, to partly intracavernous aneurysms, and to carotid-ophthalmic aneurysms, allowing control of the proximal aneurysm neck and of the parent artery itself. In cases of tumors involving the medial sphenoid ridge, the apex of the orbit, or the cavernous sinus, the pericarotid connective tissue can serve as a guide layer for access along the internal carotid artery.

Adult↗