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K Roosen

Publications and source records attributed to K Roosen.

At least 37 records · Page 2Linked to original sources
PubMed2000

Retinoids inhibit human glioma cell proliferation and migration in primary cell cultures but not in established cell lines.

OBJECTIVE: Retinoids are known to exhibit a broad spectrum of biological activities, and they participate in the onset of differentiation and the inhibition of growth in a wide variety of cancer cells. Some of these vitamin A derivatives are already in clinical use. However, data on retinoid actions in glial tumors are rather sparse. Therefore, we studied the effects of the natural retinoic acid (RA) forms all-trans-RA, 9-cis-RA, and 13-cis-RA on glioma cell lines and primary cultures from patients with glioblastomas multiforme. METHODS: Six human glioma cell lines, one rat glioma cell line, and 20 primary cultures established from biopsies from patients with glioblastomas multiforme were investigated. Tumor cell proliferation was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and cell-counting assays. Random migration out of tumor spheroids was quantified using a video-morphometry system. Invasion was investigated using a confrontational coculture test system. Retinoid receptor (RA receptor [RAR]alpha, -beta, and -gamma and retinoid X receptor [RXR]alpha, -beta, and -gamma) expression status was determined using reverse transcription-polymerase chain reaction studies. RESULTS: Treatment of five human glioma cell lines with the different retinoids at concentrations up to 10(-5) mol/L produced no reduction of proliferation, using various incubation times. For one human glioma cell line (U343MG-A) and one rat glioma cell line (C6), which were previously reported to be sensitive to retinoids, we could confirm strong inhibitory effects on proliferation and clear changes in morphological features after retinoid treatment. Application of the different retinoids to low-passage primary cultures of human glioblastomas resulted in marked inhibition of proliferation (30-95%) for all tested samples. Using three-dimensional spheroid cultures, we detected retinoid-induced decreases in cell migration (24-65%). Invasion was not affected by these vitamin A derivatives. In an analysis of the expression patterns for retinoid receptors (RARs and RXRs), all primary culture samples yielded positive results for RAR gamma and RXR alpha and negative results for RAR alpha, RAR beta, and RXR gamma, whereas the results of RXR beta expression were heterogeneous among different patients. The cell lines, irrespective of their RA sensitivities, did not exhibit any major differences in receptor expression. CONCLUSION: Retinoids strongly inhibit proliferation and migration in primary cultures of human glioblastomas multiforme. Our data support a clinical trial of retinoids for the treatment of human malignant gliomas. We observed that most established cell lines were not sensitive to RA. This difference between long-term cell lines and primary cultures cannot be explained by different retinoid receptor expression patterns.

Adult↗
PubMed2000

Quantitative parameters of intraoperative electromyography predict facial nerve outcomes for vestibular schwannoma surgery.

OBJECTIVE: Facial nerve monitoring is an established method that is routinely used during cerebellopontine angle tumor surgery. The aim of this study was to determine quantitative electromyographic (EMG) parameters that were predictive of facial nerve outcomes. METHODS: In 137 patients with intra-/extrameatal vestibular schwannomas, the most proximal (the exit from the brainstem) and distal (the fundus of the internal auditory canal) parts of the facial nerve were stimulated after total tumor removal. A quantitative analysis of absolute values and ratios (proximal/distal) of evoked EMG parameters (amplitude, latency, and duration) was performed, and parameters were correlated with postoperative (1 and 6 wk and 6 mo) facial nerve function (FNF). RESULTS: Absolute values of EMG amplitudes were statistically correlated with FNF (P < 0.05). Amplitude ratios (proximal/distal) demonstrated an even greater predictive power. The risk of exhibiting facial palsy 6 months after surgery increased from 1.6% (amplitude ratio of >0.8) to 75% (ratio of <0.1). For EMG latencies, only the ratios revealed a significant correlation with FNF. The latency ratio-dependent risk of facial palsy after 6 months increased from 2.9% (ratio of <1.05) to 33% (ratio of >1.35). The durations of the muscle responses were not significantly correlated with clinical outcomes. CONCLUSION: The predictive power of the amplitudes and latencies of electrically evoked muscle responses could be improved by calculating proximal/distal ratios. The proximal/distal amplitude ratio proved to be the most powerful parameter for intraoperative assessment of postoperative FNF.

Adult↗
PubMed2000

Vascular endothelial growth factor-driven glioma growth and vascularization in an orthotopic rat model monitored by magnetic resonance imaging.

OBJECTIVE: The goal of the present study was to develop an orthotopic in vivo model for the investigation of vascular endothelial growth factor (VEGF)-dependent glioma growth and vascularization. METHODS: C6 glioma cells were infected with viruses encoding sense or antisense VEGF. Expression of the transgene was controlled by Northern blot analysis, Western blot analysis, and immunohistochemistry. Spheroids generated from both clones as well as from wild-type and mock-transfected cells were implanted in the brains of Sprague-Dawley rats. Growth and vascularization were assessed using magnetic resonance imaging after 7 and 11 days. Histology was studied using hematoxylin and eosin staining, immunohistochemistry with anti-von Willebrand staining, anti-VEGF, anti-CD8, and assessment of vessel density. RESULTS: Cell proliferation, migration, and invasion in vitro were very similar in all cell clones. Sense gliomas demonstrated by far the fastest growth in vivo, with intense contrast enhancement meeting criteria for highly malignant tumors. Histological examination revealed masses of von Willebrand- and VEGF-positive tumor vessels with a high vessel density. Antisense gliomas depicted the radiological features of low-grade gliomas, with slow growth and poor vascularization, although they were highly infiltrative. Wild-type and mock-transfected gliomas demonstrated similar growth and vascularization patterns intermediate between sense and antisense gliomas. Any influence of the allogeneic response of the hosts on different tumor sizes could be excluded. CONCLUSION: Our model elucidates glioma growth and vascularization as strongly VEGF dependent, which is consistent with human gliomas. Thus, this model is suitable for testing antiangiogenic strategies to interfere with the VEGF/VEGF receptor system, as well as for exploring VEGF-independent mechanisms using the antisense-transfected clone.

Animals↗
PubMed2000

Acoustic neuroma surgery as an interdisciplinary approach: a neurosurgical series of 508 patients.

OBJECTIVES: To evaluate an interdisciplinary concept (neurosurgery/ear, nose, and throat (ENT)) of treating acoustic neuromas with extrameatal extension via the retromastoidal approach. To analyse whether monitoring both facial nerve EMG and BAEP improved the functional outcome in acoustic neuroma surgery. METHODS: In a series of 508 patients consecutively operated on over a period of 7 years, functional outcome of the facial nerve was evaluated according to the House/Brackmann scale and hearing preservation was classified using the Gardner/Robertson system. RESULTS: Facial monitoring (396 of 508 operations) and continuous BAEP recording (229 of 399 cases with preserved hearing preoperatively) were performed routinely. With intraoperative monitoring, the rate of excellent/good facial nerve function (House/Brackmann I-II) was 88.7%. Good functional hearing (Gardner/Robertson 1-3) was preserved in 39.8%. CONCLUSION: Acoustic neuroma surgery via a retrosigmoidal approach is a safe and effective treatment for tumours with extrameatal extension. Functional results can be substantially improved by intraoperative monitoring. The interdisciplinary concept of surgery performed by ENT and neurosurgeons was particularly convincing as each pathoanatomical phase of the operation is performed by a surgeon best acquainted with the regional specialties.

Adolescent↗
PubMed2000

Is there a benefit of preoperative meningioma embolization?

OBJECTIVE: To evaluate the effect of preoperative embolization of meningiomas on surgery and outcomes. METHODS: In a prospective study, 60 consecutive patients with intracranial meningiomas who were treated in two neurosurgical centers were included. In Center A, embolization was performed for none of the patients (n = 30). In Center B, 30 consecutive patients with embolized meningiomas were treated. Preoperatively, tumor size and location, neurological status, and Barthel scale score were recorded. In Center B, the extent of tumor devascularization was evaluated using angiography and postembolization magnetic resonance imaging. Intraoperatively, blood loss, the numbers of blood units transfused, and the observations of the neurosurgeon concerning hemostasis, tumor consistency, and intratumoral necrosis were recorded. Postoperatively, the neurological status and duration of hospitalization were recorded. Six months after surgery, the outcomes were assessed using the Barthel scale and neurological examinations. RESULTS: The mean tumor sizes were 22.9 cc in Center A and 29.6 cc in Center B (P > 0.1). The mean blood losses did not differ significantly (646 ml in Center A versus 636 ml in Center B; P > 0.5). However, for a subgroup of patients with subtotal devascularization (>90% of the tumor) on postembolization magnetic resonance imaging scans in Center B, blood loss was less, compared with the entire group in Center A (P < 0.05). The observations of the neurosurgeon regarding hemostasis, tumor consistency, and intratumoral necrosis did not differ significantly. There were no surgery-related deaths in either center. The rates of surgical morbidity, with permanent neurological worsening, were 20% (n = 6) in Center A and 16% (n = 5) in Center B. There was one permanent neurological deficit (3%) caused by embolization. CONCLUSION: In this preliminary study, only complete embolization had an effect on blood loss. The value of preoperative embolization for all meningiomas must be reconsidered, especially in view of the high costs and risks of embolization.

Adult↗
PubMed1999

Microglial/macrophage expression of interleukin 10 in human glioblastomas.

Interleukin 10 (IL-10) expression has been found to be correlated with the extent of malignancy in gliomas. In vitro, IL-10 increases proliferation and migratory capacity in human glioma cell lines. In this study, we localized the site of IL-10 synthesis in gliomas to cells of microglial origin. Biopsy specimens from 11 patients with malignant glioma were processed on native tissues and at early cell culture passages (0-4). IL-10 mRNA was analyzed by RT-PCR and in situ hybridization. Protein was quantitatively assessed by ELISA in cell culture supernatants, and cells expressing IL-10 were determined by a combination of immunohistochemistry for CD68 (specific for microglia/macrophage lineage) and IL-10 in situ hybridization. IL-10 mRNA decreased from passage 0 to 4 in all samples and was undetectable beyond passage 5. Such downregulation of mRNA leads to a steep decrease of IL-10 protein in culture supernatants (below detection level, 0.05 ng/ml, beyond passage 1). The combination of in situ hybridization for IL-10 and CD68 immunostaining revealed that only cells of the microglia/macrophage lineage produced IL-10 mRNA. Our results identify microglia/macrophage cells as the major source of IL-10 expression in gliomas which decreases markedly during early passages of primary cultures of human gliomas due to a progressive reduction of microglia/macrophages present.

Adult↗
PubMed1999

Effect of synthetic matrix-metalloproteinase inhibitors on invasive capacity and proliferation of human malignant gliomas in vitro.

Glioma invasion into the surrounding brain tissue is still a major obstacle for any therapeutical approach. As in other solid tumors, matrix-metalloproteases (MMPs) have been suggested as being involved. The aim of this study was to evaluate whether the use of MMP inhibitors to target the protease-mediated invasion process could be a feasible approach. Two human cell lines (U251 and GaMG) and surgical specimens of 6 patients with malignant gliomas were grown as monolayers and spheroid cultures respectively. MMP- and u-PA-mRNA expression was investigated by semi-quantitative RT-PCR. Invasion was studied in Matrigel-coated Boyden chamber transwell assays for monolayers and in confrontation cultures of tumor spheroids with fetal rat brain aggregates in the presence of the synthetic MMP inhibitors batimastat (BB-94) and marimastat (BB-2516). Cytotoxicity/cytostatic effects of high concentrations of both compounds were assessed by growth curves, MTT assays and flow cytometry in human glioma cell lines. Batimastat and marimastat revealed a cytostatic effect at high concentrations (above 1 microM) without cytotoxicity. Both MMP inhibitors effectively reduced glioma invasion in Boyden-chamber assays at low concentrations of 0.3 microM. In confrontation cultures, concentrations of 10 microM and above were necessary to reduce invasion. This effect was observable with inter-individual heterogeneity in the patient's tumor material. MMP inhibitors effectively reduce glioma invasion, although high concentrations were required in 3-dimensional culture systems. At these concentrations, both compounds revealed a cytostatic, but no cytotoxic effect. Thus, high local concentrations of MMP inhibitors could offer a new therapeutic strategy for the treatment of gliomas.

Animals↗
PubMed1999

Vascularization of human glioma spheroids implanted into rat cortex is conferred by two distinct mechanisms.

Aim of this study was to develop and characterize an applicable in vivo model to investigate angiogenesis of human gliomas. An established glioblastoma spheroid model was used to investigate the neovascularization of a standardized avascular solid tumor mass. Spheroids of two human glioma cell lines were labeled with an in vivo fluorescent dye. Single spheroids were implanted into the cortex of athymic rats. After 1, 3, 7, 14, and 21 days, brain sections containing the spheroid were immunostained for endothelial cells or vascular endothelial growth factor (VEGF). The dye-stained glioma spheroid and the endothelial cells were visualized by confocal microscopy. Two distinct mechanisms of tumor vascularization could be observed. (1) "Classical" angiogenesis with new vessels sprouting from existing host vessels into the spheroid was seen. (2) Individual endothelial cells were found to migrate towards and into the center of the spheroid where they coalesced to form new vessels. This process occurred as early as 24 hr after spheroid implantation. Spheroid vascularization was accompanied by an increase of VEGF expression, which peaked 7 days after implantation and returned to normal patterns by 14-21 days. Besides the "classical" angiogenesis by angiogenic blood vessels, the recruitment of individual endothelial cells seems to be an additional mechanism in early glioma vascularization. Our model proves to be a reliable, reproducible system to study in vivo angiogenesis of human gliomas.

Animals↗
PubMed1999

[Cerebral aneurysms in the posterior circulation. Treatment results in 44 consecutive cases].

PURPOSE: Evaluation of clinical and morphological results in 44 consecutive patients with 45 aneurysms of the posterior circulation. METHODS: Retrospective analysis of patient charts and angiograms of all vertebrobasilar aneurysms diagnosed in our department between 10/95 and 08/99. All aneurysms were treated. RESULTS: 36/44 pts had a hemorrhage. Hunt/Hess (HH) gradings were as follows: HH1 in 10, HH2 in 6, HH3 in 9, HH4 in 10 cases, and HH5 in 1 case. 38 pts with 39 aneurysms were treated exclusively in the endovascular way, 3 pts with 3 aneurysms were operated on. 3 patients had to be operated upon following insufficient endovascular treatment. Endovascular treatment resulted in 63% total and 27% subtotal occlusions, results being stable in 85%. For our pts as a whole, the grading according to the Glasgow Outcome Scale (GOS) was GOS1 in 4, GOS3 in 8, GOS4 in 7, and GOS5 in 25 cases. CONCLUSION: Despite a less favourable clinical status of pts pre-treatment, the results of our interdisciplinary concept compare favourably with those of other surgical or interventional groups.

Adult↗
PubMed1999

"De novo" formation of intracranial aneurysms: who is at risk?

Although aneurysms are widely considered to be of congenital origin there is still debate as to whether some at least might be formed de novo during life. A review of all 49 reported cases plus one previously unpublished case reveals common clinical features and might aid in the management of this group of patients. Statistical analysis of all 50 cases of de novo aneurysms discloses a more frequent history of smoking (P = 0.0007) and arterial hypertension (P = 0.0026) than in a control cohort. Patients with de novo aneurysms are younger (P < 0.0001); the proportion with multiple aneurysms was 28 %. Of de novo aneurysms 44 % became symptomatic 3-6 years after the first subarachnoid haemorrhage (SAH), and the interval was significantly shorter in hypertensive patients. We suggest that young patients with a history of SAH and arterial hypertension and nicotine abuse should therefore be considered for conventional angiography after a 5-year interval. MRA might not be useful due to clip artefacts from even nonferromagnetic clips. Close control of blood pressure is essential in these patients.

Adolescent↗
PubMed1999

Localization and characterization of intracerebral cavernous angiomas by intra-operative high-resolution colour-duplex-sonography.

The aim of this prospective study was to evaluate the reliability of high-resolution Colour-Duplex-Sonography (= CDS) in intra-operative localization, guiding and characterization of intracerebral cavernous angiomas (= CA). During a time period from 5/93 to 12/96 a total of 26 patients with 21 supratentorial and 5 infratentorial CA (15 of them deep-seated) were examined intra-operatively by CDS. The study focussed on 1. sonographic characterization, 2. localization in relationship to anatomical landmarks, 3. navigation, 4. correlation of sonographic to magnetic resonance imaging (= MRI), intra-arterial angiography (= DSA) and histological results and 5. control of complete resection. All CA appeared sonographically as hyperechoic lesions without flow-signals in Colour-mode. Imaging of anatomical landmarks as cerebral sulci, brain stem, insular cistern, falx, ventricles and vessels could be used for precise localization and successful guiding to 15 deep-seated lesions. The correlation of the size between MRI and CDS was excellent (1.4 mm mean difference, range from 0 to 5 mm). All 4 associated venous anomalies, as verified by pre-operative DSA, could be visualized and identified by CDS. The completeness of exstirpation was controlled sonographically in 14 cases and confirmed by MRI (= 10) and CT (= 4). This study provides the first comprehensive intra-operative characterization of CAs by CDS and correlation to MRI and DSA. Furthermore it demonstrates the reliability of CDS for intra-operative localization and guiding as well as its potential to control the complete exstirpation.

Adolescent↗
PubMed1999

Expression of different extracellular matrix components in human brain tumor and melanoma cells in respect to variant culture conditions.

Local tumor invasion into the surrounding brain tissue is a major characteristic of malignant gliomas. These processes critically depend on the interaction of tumor cells with various extracellular matrix (ECM) components. Because only little quantitative information about expression of ECM gene products in general and expression in response to alterations of the surrounding environment is available, the present study was designed. Four human glioblastoma cell lines (U373MG, U138MG, U251MG, GaMG) as well as four human melanoma cell lines (MV3, BLM, 530, IF6) were tested with semiquantitative RT-PCR for their ability to express mRNA of different human ECM components (fibronectin, decorin, tenascin, collagen I, collagen IV, versican). In addition, two human medulloblastoma (MHH-Med 1, MHH-Med 4) and two fibrosarcoma (HT1080, U2OS) cell lines were analyzed. Cells which were grown in DMEM medium containing 10% FCS expressed most of the analyzed protein components. When the same medium, but depleted of ECM proteins by filtrating through a membrane with cut-off at > 100 kD was used, basal mRNA expression of the ECM proteins was changed in most of the examined cell lines. Using serum free conditions, most of the cell lines again showed a variation in the expression pattern of mRNA encoding for the different ECM proteins compared to the other medium conditions. Comparing different cell lines from one tumor entity or different tumor groups, ECM expression was heterogeneous with regard to the different tumor entities as well as within the entities themselves. Migration assays revealed heterogeneous responses between the different cell lines, ECM components and culture conditions, making it difficult to correlate ECM expression patterns and migratory behavior. Our results revealed that all examined cell lines are able to produce ECM proteins in vitro. This suggests that tumor cells can modulate their microenvironment in vitro which has to be taken into consideration for studies related to migration and invasion.

Brain Neoplasms↗
PubMed1999

Technical developments in intra-operative monitoring for the preservation of cranial motor nerves and hearing in skull base surgery.

Although EMG recordings from mimic muscles have become the standard for intra-operative facial nerve monitoring, few data are available concerning other motor cranial nerves (MCN). Auditory brainstem responses (ABR) are a proven tool for intra-operative hearing preservation, but have their limitations, suggesting the application of supplementary methods. This paper describes new developments of MCN and cochlear nerve monitoring in skull base surgery. Up to 2 x 8 EMG channels were recorded after bipolar stimulation of MCN using concentric coaxial probes. A special software enabled event-dependent registrations of all signals exceeding a definable threshold level. Selective recordings from masticatory muscles (N.V) were obtained using rectangular Teflon-insulated needle electrodes. For oculomotor (Nn.III/ VI) nerve recordings bipolar needle electrodes were precisely placed by orbital ultrasound guidance. Lower cranial nerves were monitored inserting needle electrodes into the soft palate (N.IX), tongue (N.XII) and vocal muscles (N.X) during laryngoscopy using a special applicator. For ABR recordings, click stimuli (95 dB HL) were applied monaurally through insert earphones. Electrocochleography was simultaneously recorded as a near-field potential without averaging after promontory (transtympanic) electrode placement using otomicroscopy. Regarding the ABR biosignal, a characteristic response pattern was detected following bipolar electrical stimulation of the auditory nerve possibly useful for its intra-operative identification.

Cochlear Nerve↗
PubMed1999

Interrelations of laser doppler flowmetry and brain tissue oxygen pressure during ischemia and reperfusion induced by an experimental mass lesion.

The objective of this study was to assess interrelations between bilateral changes of cortical laser doppler flowmetry and intraparenchymal, subcortical partial tissue oxygen tension in the course of an experimental trauma. Ten animals served as a sham group, 8 Sprague-Dawley rats received an unilateral, focal parietal mass lesion. The bilateral course of cortical blood flow measured by laser doppler flowmetry (LDF) was correlated with subcortical, intraparenchymal partial tissue oxygen tension [p(ti)O2]. In the sham-operated group, laser doppler mean flow values drifted between 9.0% and 9.5% and showed no significant changes over time neither between the hemispheres nor within each hemisphere. Absolute mean p(ti)O2 in sham-operated animals was 32.4 mm Hg in the left and 30.5 mm Hg in the right hemisphere. In the trauma group, mean laser doppler flow values during maximum brain compression decreased ipsilateral to 20.3% and contralateral to 34.4% of the baseline values. P(ti)O2 decreased ipsilateral from 25.9 to 6.6 mm Hg (25.4%) and contralateral from 22.6 to 9.8 mm Hg (43.6%). After balloon deflation, cortical LDF was restored much faster compared to p(ti)O2, but did not reach baseline values [ipsilateral 61.6% (p < 0.05); contralateral 75.8% of baseline values]. The p(ti)O2 values reached 25.2 mm Hg (97%) ipsilateral and 23.7 mm Hg (105%) contralateral. A temporary phase of reactive hyperemia occurred sporadically shortly after decompression. Both parameters showed a significant but rather weak correlation (r = 0.56; p < 0.001). Based upon these findings, we conclude that intraparenchymal, subcortical p(ti)O2 measurements supplemented on-line cortical CBF monitoring and score out discontinuous alternative measurement techniques in detecting hemodynamically relevant events. The small spatial resolution of LDF and p(ti)O2 probes, however, which in the small animal model may be of negligible influence, does raise the question whether the values obtained represent the microcirculatory situation of the human brain.

Animals↗
PubMed1998

DNA ploidy and cell-cycle analysis in intracranial meningiomas and hemangiopericytomas: a study with high-resolution DNA flow cytometry.

Although various DNA flow-cytometric studies have been performed on meningiomas, the role of DNA ploidy and the S-phase fraction (SPF) in predicting biological tumor behavior remains unresolved. Discrepant results in earlier studies might be due to different preparing, staining and measuring techniques; different quality standards; and lack of sophisticated computer software. In this study, high-resolution DNA flow cytometry using the DNA-specific dye DAPI (4', 6'-diamidino-2-phenylindol) was performed on stored frozen tissue from 128 microsurgically resected meningiomas and 7 hemangiopericytomas, including 17 recurrent meningiomas and 4 recurrent hemangiopericytomas. The computer software Multicycle 2.5 was used to determine the ploidy level and to perform cell-cycle analysis. DNA aneuploidy and SPF were significantly higher in atypical, anaplastic and recurrent meningiomas and correlated well with histopathological features such as focal necrosis, infiltration of dura mater and mitotic activity. Among 128 meningiomas, 42 had additional DNA aneuploid stem lines. No association between hypo- and hyperploidy and either histological subtype or clinical outcome was found. In 7 hemangiopericytomas, SPF was significantly higher compared to the benign meningioma group, while only 1 tumor was aneuploid. In all 42 DNA aneuploid tumors, cell-cycle analysis was performed separately for the euploid and aneuploid stem lines. The proliferation parameters (SPF, G2/M phase) were significantly higher in the DNA aneuploid stem lines. DNA ploidy and SPF are thus useful indicators of different biological behavior within identical histological subgroups in meningiomas.

Aneuploidy↗
PubMed1998

Bilateral monitoring of CBF and tissue oxygen pressure in the penumbra of a focal mass lesion in rats.

The continuous monitoring of cerebral microcirculation is aimed at preventing secondary ischemic brain damage subsequent to severe head injury. Interrelations between bilateral changes of cortical Laser Doppler Flowmetry (LDF) and intraparenchymal, subcortical p(ti)O2 values were continuously monitored in the forebrain of rodents. A trauma group of 8 animals received an unilateral, focal parietal mass lesion by an expanding epidural balloon. 10 animals served as a sham group. In the sham-operated group the drift of median LDF values was 10.8% in the left and 9.6% in the right hemisphere. The absolute median p(ti)O2 showed values of 31.2 mm Hg (27.9-34.9) in the left and 30.1 mm Hg (27.5-31.7) in the right hemisphere. During maximum brain compression median LDF values decreased ipsilateral to 18.6% (13.3-24.4%) and contralateral to 23.4% (17.1-56.6%) of the baseline values. P(ti)O2 decreased ipsilateral to absolute values of 4.6 mm Hg (3.2-6.7 mm Hg) and contralateral to values of 7.1 mm Hg (6.1-8.5 mm Hg). After balloon deflation cortical LDF was restored much faster but did not reach baseline values [ipsilateral 55.2% (42.6-67.8%); contralateral 67% (53.4-82%) of baseline values]. The p(ti)O2 values reached ipsilateral 77.4% (72.0-93.3%) and contralateral 88.8% (86.0-97.4%) of baseline values. Both parameters showed a significant correlation (r = 0.57; p < 0.02). P(ti)O2 measurements supplement on-line cortical CBF monitoring and by far outscore discontinuous alternative measurement techniques in detecting hemodynamically relevant events. The small spatial resolution of the p(ti)O2 probes, however, which in the small animal model may be of negligible influence, does raise the question whether the values gained offer a general overview of the microcirculatory situation.

Animals↗
PubMed1998

Decompressive craniectomy in patients with uncontrollable intracranial hypertension.

There has been controversial discussion about the benefits of decompressive craniectomy in patients with critically raised intracranial pressure (ICP) after severe head injury. The aim of this retrospective study was to analyze the results of secondary decompressive craniectomy in patients with uncontrollable raised ICP after maximum aggressive medical treatment. The data of 28 patients (mean age 22 years, range 8-44 years) with severe head injury and posttraumatic cerebral edema were analyzed retrospectively. Surgery was not indicated in patients with vast primary lesions, hypoxia, ischemic infarction, brainstem injuries and central herniation. The outcome was classified according to the Glascow Outcome Scale (GOS) after one year. The decompressive crainectomy was performed an average of 68 hours after trauma, and ICP (< 25 mm Hg) decreased always while cerebral perfusion pressure (CPP > 75 mm Hg) improved as well as cerebral blood flow and microcirculation to normal values. 15 patients (56%) had a good outcome after one year (GOS 4 + 5). 5 patients (18%) were severely disabled, 4 patients (14%) remained in vegetative state and 3 patients (11%) died. Decompressive craniectomy should be kept in mind as the last therapeutic step, especially in young patients with head injury and raised ICP, which is not controllable with conservative methods.

Adolescent↗