Patterns, predictors and prognostic relevance of high-grade hematotoxicity after temozolomide or temozolomide-lomustine in the CeTeG/NOA-09 trial.

PURPOSE: In the randomized phase III trial CeTeG/NOA-09, temozolomide (TMZ)/lomustine (CCNU) combination therapy was superior to TMZ in newly diagnosed MGMT methylated glioblastoma, albeit reporting more frequent hematotoxicity. Here, we analyze high grade hematotoxicity and its prognostic relevance in the trial population. METHODS: Descriptive and comparative analysis of hematotoxicity adverse events ≥ grade 3 (HAE) according to the Common Terminology of Clinical Adverse Events, version 4.0 was performed. The association of HAE with survival was assessed in a landmark analysis. Logistic regression analysis was performed to predict HAE during the concomitant phase of chemotherapy. RESULTS: HAE occurred in 36.4% and 28.6% of patients under CCNU/TMZ and TMZ treatment, respectively. The median onset of the first HAE was during concomitant chemotherapy (i.e. first CCNU/TMZ course or daily TMZ therapy), and 42.9% of patients with HAE receiving further courses experienced repeat HAE. Median HAE duration was similar between treatment arms (CCNU/TMZ 11.5; TMZ 13 days). Chemotherapy was more often discontinued due to HAE in CCNU/TMZ than in TMZ (19.7 vs. 6.3%, p = 0.036). The occurrence of HAE was not associated with survival differences (p = 0.76). Regression analysis confirmed older age (OR 1.08) and female sex (OR 2.47), but not treatment arm, as predictors of HAE. CONCLUSION: Older age and female sex are associated with higher incidence of HAE. Although occurrence of HAE was not associated with shorter survival, reliable prediction of patients at risk might be beneficial to allow optimal management of therapy and allocation of supportive measures. TRIAL REGISTRATION: NCT01149109.

The choice of the hypnotic drug (volatile or propofol) for maintenance of anesthesia does not influence surgical conditions during cranioplasty.

BACKGROUND AND AIMS: In contrast to propofol, volatile agents are often considered harmful to maintain anesthesia due to increasing brain volume and potential deleterious effects. Patients for cranioplasty, including patients with large bone defects, could be susceptible for intraoperative complications but have not properly been investigated so far. The aim of the present study was to evaluate brain swelling, intraoperative conditions, surgical course, and postoperative complication rates of propofol-based vs. volatile-based anesthesia. MATERIAL AND METHODS: In this monocentric, retrospective, and observational study, we collected demographic, clinical, and outcome data of patients undergoing cranioplasty between December 2010 and September 2014. According to the hypnotic drug used, patients were assigned to either a propofol or a volatile group. The primary outcome parameter was brain swelling. For comparison of the groups, univariate analysis was performed using Chi-square and Mann-Whitney-U test. RESULTS: One hundred and one patients were identified in the period. Twenty-three patients were excluded due to cerebrospinal fluid diversion. Baseline characteristics and preoperative conditions did not vary between the groups except a higher body mass index and positive end-expiratory pressure (PEEP) in the propofol group. The choice of anesthesia (volatile or intravenous) influence neither the intraoperative local conditions nor postoperative complication rate. No significant risk factor for impaired bone flap placement was identified. CONCLUSIONS: In a well-defined cohort, the choice of the anesthetic agent does not influence the degree of intraoperative brain swelling, bone flap fit, and postoperative course.

Economic burden of Clostridium difficile associated diarrhoea: a cost-of-illness study from a German tertiary care hospital.

PURPOSE: Clostridium difficile associated diarrhoea (CDAD) is the most common cause of health-care-associated infectious diarrhoea. In the context of the German health-care system, direct and indirect costs of an initial episode of CDAD and of CDAD recurrence are currently unknown. METHODS: We defined CDAD as presence of diarrhoea (≥3 unformed stools/day) in association with detection of Clostridium difficile toxin in an unformed faecal sample. Patients treated with metronidazole (PO or IV) and/or vancomycin (PO) were included. Comprehensive data of patients were retrospectively documented into a database using the technology of the Cologne Cohort of Neutropenic Patients (CoCoNut). Patients with CDAD were matched to control patients in a 1:1 ratio. Analysis was split in three groups: incidence group (CDAD patients without recurrence), recurrence group (CDAD patients with ≥1 recurrence) and control group (matched non-CDAD patients). RESULTS: Between 02/2010 and 12/2011, 150 patients with CDAD (114 patients in the incidence and 36 (24 %) in the recurrence group) and 150 controls were analysed. Mean length of stay was: 32 (95 %CI: 30-37), 94 (95 %CI: 76-112) and 24 days (95 %CI: 22-27; P = <0.001), resulting in mean overall direct treatment costs per patient of €18,460 (95 %CI: €14,660-€22,270), €73,900 (95 %CI: €50,340-€97,460) and €14,530 (95 %CI: €11,730-€17,330; P = <0.001). In the incidence and recurrence group, the mean cumulative number of antibiotic CDAD treatment days was 11 (95 %CI: 10-12) and 36 (95 %CI: 27-45; P = <0.001). CONCLUSIONS: Especially CDAD recurrence was associated with excessive costs, which were mostly attributable to a significantly longer overall length of stay. Innovative treatment strategies are warranted to reduce treatment costs and prevent recurrence of CDAD.

[Brain metastases-Interdisciplinary approach towards a personalized treatment]. / Hirnmetastasen ­ interdisziplinär zu einer personalisierten Behandlung.

The incidence, treatment and prognosis of patients with brain metastases have substantially changed during the last decades. While the survival time after diagnosis of cerebral metastases was on average a maximum of 3-6 months only 10 years ago, the survival time could be significantly improved due to novel surgical, radiotherapeutic and systemic treatment modalities. Only a few years ago, the occurrence of brain metastases led to a withdrawal from systemic oncological treatment and the exclusion of drug therapy studies and to a purely palliatively oriented treatment in the sense of whole brain radiation therapy (WBRT) with or without surgery. The increasing availability of targeted and immunomodulatory drugs as well as adapted radio-oncological procedures enable increasingly more personalized treatment approaches. The aim of this review article is to demonstrate the progress and complexity of the treatment of brain metastases in the context of modern comprehensive interdisciplinary concepts.

Headache in patients with a meningioma correlates with a bone-invasive growth pattern but not with cytokine expression.

We included 58 patients with meningioma in a prospective study to analyse the prevalence of and risk factors for different types of meningioma-associated headache. Twenty-three patients (40%) had meningioma-associated headache. Of these, the pain was migraine-like in five (22%) and tension-type headache (TTH)-like in 13 (57%). Sixteen of 21 (76%) experienced relief of pain intensity of at least 50% after 18-24 months. Univariate analysis revealed bone-invasive growth pattern (P = 0.007) as a risk factor for headache and intake of antiepileptic drugs (P = 0.04) or large surrounding oedema (P = 0.04) as possible protective parameters. For migraine-like headache, risk factors were a positive history of migraine (P = 0.009) and bone-invasive growth pattern (P = 0.046) and, for TTH-like headache, only bone-invasive growth pattern (P = 0.009). Binary logistic regression analysis added to assess predictability and interaction effects could not identify a single factor predicting the occurrence of headache in the presence of a meningioma (correct prediction in 74% by a model consisting of bone-invasive growth pattern, history of head surgery, intake of antiepileptic drugs, temporal tumour location and moderate and large surrounding oedema). Analysis of 38 tumour specimens could not confirm the hypothesis that the occurrence of headache correlates with the expression magnitude of signal substances known to be present in meningiomas [stroma cell-derived factor 1, interleukin (IL)-1ß, IL-6, vascular endothelial growth factor A] or thought to be relevant to headache/pain pathophysiology [prostaglandin-endoperoxide synthase 2, calcitonin-related polypeptide alpha, nitric oxide synthase (NOS) 1, NOS2A, NOS3, transforming growth factor-alpha, tumour necrosis factor, tachykinin, vasoactive intestinal peptide]. The affection of bone integrity and the expression of molecules thought to be relevant to headache pathophysiology might be important for meningioma-associated headache in predisposed individuals.

Navigated Transtubular Extraforaminal Decompression of the L5 Nerve Root at the Lumbosacral Junction: Clinical Data, Radiographic Features, and Outcome Analysis.

Purpose. Extraforaminal decompression of the L5 nerve root remains a challenge due to anatomic constraints, severe level-degeneration, and variable anatomy. The purpose of this study is to introduce the use of navigation for transmuscular transtubular decompression at the L5/S1 level and report on radiological features and clinical outcome. Methods. Ten patients who underwent a navigation-assisted extraforaminal decompression of the L5 nerve root were retrospectively analyzed. Results. Six patients had an extraforaminal herniated disc and four had a foraminal stenosis. The distance between the L5 transverse process and the para-articular notch of the sacrum was 12.1 mm in patients with a herniated disc and 8.1 mm in those with a foraminal stenosis. One patient had an early recurrence and another developed dysesthesia that resolved after 3 months. There was a significant improvement from preoperative to postoperative NRS with the results being sustainable at follow-up. ODI was also significantly improved after surgery. According to the Macnab grading scale, excellent or good outcomes were obtained in 8 patients and fair ones in 2. Conclusions. The navigated transmuscular transtubular approach to the lumbosacral junction allows for optimal placement of the retractor and excellent orientation particularly for foraminal stenosis or in cases of complex anatomy.

Multimodal Imaging in Malignant Brain Tumors: Enhancing the Preoperative Risk Evaluation for Motor Deficits with a Combined Hybrid MRI-PET and Navigated Transcranial Magnetic Stimulation Approach.

BACKGROUND AND PURPOSE: Motor deficits in patients with brain tumors are caused mainly by irreversible infiltration of the motor network or by indirect mass effects; these deficits are potentially reversible on tumor removal. Here we used a novel multimodal imaging approach consisting of structural, functional, and metabolic neuroimaging to better distinguish these underlying causes in a preoperative setting and determine the predictive value of this approach. MATERIALS AND METHODS: Thirty patients with malignant brain tumors involving the central region underwent a hybrid O-(2-[(18)F]fluoroethyl)-L-tyrosine-PET-MR imaging and motor mapping by neuronavigated transcranial magnetic stimulation. The functional maps served as localizers for DTI tractography of the corticospinal tract. The spatial relationship between functional tissue (motor cortex and corticospinal tract) and lesion volumes as depicted by structural and metabolic imaging was analyzed. RESULTS: Motor impairment was found in nearly all patients in whom the contrast-enhanced T1WI or PET lesion overlapped functional tissue. All patients who functionally deteriorated after the operation showed such overlap on presurgical maps, while the absence of overlap predicted a favorable motor outcome. PET was superior to contrast-enhanced T1WI for revealing a motor deficit before the operation. However, the best correlation with clinical impairment was found for T2WI lesion overlap with functional tissue maps, but the prognostic value for motor recovery was not significant. CONCLUSIONS: Overlapping contrast-enhanced T1WI or PET-positive signals with motor functional tissue were highly indicative of motor impairment and predictive for surgery-associated functional outcome. Such a multimodal diagnostic approach may contribute to the risk evaluation of operation-associated motor deficits in patients with brain tumors.

ECM-mediated glioma cell invasion.

Cell adhesion receptors of the integrin superfamily, CD44, and adhesion receptors of the immunoglobulin superfamily are expressed by high-grade astrocytic tumors of the central nervous system. These receptors are critical for the invasion of these tumors in the nervous system. Glioma cells utilize these receptors to adhere to and migrate along the components of the extracellular matrix, which is uniquely distributed and regulated within the brain and the spinal cord. For this reason, glioma cell invasion into the adjacent brain tissue is dependent on the interaction of glioma cells with the extracellular matrix. The receptor-ECM component interaction is discussed, focusing on the role of cell adhesion molecules of the integrin family and CD44 in glioma cell adhesion and invasion.

Heterogeneous regional expression patterns of matrix metalloproteinases in human malignant gliomas.

The aim of the study was to assess the differential intra- and intertumoral heterogeneity and patterns of matrix metalloproteinase expression in human glioblastomas in vivo. 12 glioblastoma samples were analyzed for MMP expression by semi-quantitative RT-PCR. A total of 56 samples (8 adjoining regions of 6 glioblastoma tumors) were immunohistochemically examined for the expression and regional distribution of gelatinase-A (MMP-2), gelatinase-B (MMP-9), matrilysin (MMP-7) and stromelysin-1 (MMP-3). Gelatinase-A mRNA was detected in all samples, gelatinase-B was found in numerous samples. Correspondingly, strong expression levels of both gelatinase protein was seen in immunohistochemistry. Gelatinase-A was expressed by both tumor cells and endothelium while gelatinase-B was found to be restricted to endothelial cells. Stromelysin-1 protein was not detected in any of the samples. Matrilysin was found around tumor cells of three samples from one patient only. The strong immunoreactivity seen for gelatinase-A around tumor cells and blood vessels suggests a role in both tissue degradation and tumor neoangiogenesis which is in accordance with previously published in vitro data. The marked localization of gelatinase-B to the endothelium and its presence in non-infiltrative benign lesions, however, makes a direct proteolytic role of gelatinase-B on ECM components during glioma invasion appear unlikely. Its close association with vascular structures, however, might indicate a link to neoangiogenesis. The significance of matrilysin which was only seen in tumor cells in three samples remains unclear. Stromelysin-1, though strongly expressed in cell lines, does not appear to play a role in glioblastoma tumors in vivo.

Glioma cell migration is associated with glioma-induced angiogenesis in vivo.

To simultaneously assess glioma cell invasion and glioma angiogenesis in vivo by non-invasive and quantitative means, DiI-labeled C6 glioma spheroids were implanted into the dorsal skinfold chamber preparation of nude mice (n = 6). Heat-inactivated spheroids served as controls to distinguish between active and passive cell spread. Using multi-fluorescent intravital videomicroscopy, glioma cell migration was analyzed on days 1-4, 6, and 10 and spheroid vascularization was analyzed on days 3, 6, and 10 after implantation. Additionally, C6 glioma spheroids were implanted into the chronic cranial window of nude mice as an orthotopic implantation site (n = 4). In the dorsal skinfold chamber, spheroids were vascularized within 10 days and revealed a tumor-specific microvasculature. In parallel, individual glioma cells detached from the spheroid edge and migrated centrifugally demonstrating an affinity to tumor and host vessels. Glioma cells demonstrated a heterogeneous pattern of their regional migratory activity (0.2-9.6 microm/h) which correlated well with regional glioma angiogenesis (r = 0.733). Using the cranial window, glioma cells spread similarly demonstrating an affinity to the perivascular space of pial/subpial vessels with preference to the arteriolar segments. Intravital fluorescence microscopy represents a versatile technique to assess the complex relationship between glioma-driven angiogenesis and glioma cell invasion.

Different vascular patterns of medulloblastoma and supratentorial primitive neuroectodermal tumors.

Astrocytoma vasculature patterns differ according to histological grade of malignancy with glioblastoma multiforme (WHO grade IV) showing most extensive endothelial proliferation. Here, we determined whether the vascular patterns of medulloblastoma and supratentorial primitive neuroectodermal tumors (PNETs), which can be hardly distinguished histopathologically, differ. We evaluated the spatial organization of vessels in medulloblastomas and PNETs using antibodies to von Willebrand factor (vWF) and CD34. Medulloblastoma capillaries showed slight endothelial cell hyperplasia. Microvessels sprouted from the capillaries and formed glomeruloid clusters. There were areas with chains of unopposed endothelial cells (3-10 cells). Supratentorial PNETs had highly branched capillaries with extensive endothelial cell hyperplasia. Glomeruloid arrays of microvessels extended from the capillaries. Small fragments of endothelial tubes were scattered throughout the tumor. Therefore, medulloblastomas and supratentorial PNETs showed different spatial organization of tumor vessels which can be used for differentiation of each tumor entity. These vascular patterns may reflect different tumor derived angiogenic stimuli.

Clinical outcome of sural nerve biopsy: a retrospective study.

Sural nerve biopsy is a valuable tool in establishing the diagnosis and investigating the underlying causes of peripheral neuropathies. Few investigations have been carried out in which the sequelae of this procedure have been described systematically. We studied the short-term adverse reactions in 110 patients and the long-term outcome of sural nerve biopsy in a subgroup of 54 patients after 5-32 months. Long-lasting sensory deficits were reported in 93%, dysaesthesia in 19% and mild persistent pain in 33% of the 54 patients. No significant differences were found between patients followed for 1-2 years and those followed for more than 2 years in the frequency and distribution of hypaesthesia and anaesthesia. However, dysaesthesia was less frequent after more than 2 years (6/32 vs 1/16), and persistent pain completely subsided within our observation period. We conclude that disabling sequelae regress and finally subside over time. If we assume that returning for follow-up visits may cause bias towards more severely affected patients, the overall prognosis may be even better.

Fast blue, a fluorescent tracer in glioma cell culture, affects cell proliferation and motility.

The azo-dye, Fast Blue (FB), initially employed for retrograde neuronal tracing is increasingly used in cell invasion and migration studies to detect living cells in monolayer and glioma tumor cell spheroid models. As yet, it is assumed that a cell stained with a tracker dye retains the characteristics of the original cell. The following experiments compared the adhesion, migration and proliferation properties of the cell lines U373 and GaMG with and without FB staining. FB staining reduced cell adhesion (P < 0.01) and proliferative activity (P < 0.01) and also had a significant inhibitory effect on cell migration (P < 0.001). From the results presented it follows that FB staining markedly influences basic cell characteristics.

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.

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.

Transfection and dye premarking of human and rat glioma cell lines affects adhesion, migration and proliferation.

It is assumed that a cell that is transfected for any gene addition or replacement or was premarked with a cell tracker dye retains the characteristics of the original cell. The following experiments compare the original C6 rat glioma cell line with C6 cells transfected with the retroviral plasmid LacZ, and the human glioma cell lines GaMG, U373, U251, and D54 with cells stained with tracker dyes (Dil and DiO). We tested adhesion, migration and proliferation. C6 cell transfection did not affect adhesion but decreased (p < 0.05) migration. Dil staining resulted in a significant decrease (p < 0.01) in adhesion in all cell lines but U251. After DiO staining human cell lines U373 and D54 displayed a decrease in adhesion (p < 0.01) whereas U251 and GaMG cells had enhanced adhesion (p < 0.01). Dye marking of C6, GaMG and U373 cells did not alter migratory capacity. In contrast, Dil and DiO reduced migration of U251 and D54 cells (p < 0.05). There was a decrease (p < 0.01) in proliferation of the human cell lines after Dil staining. Transfection or membrane dyes can alter basic cell characteristics. The assumption that a transfected or dye marked cell is the same as the original cell but with an additional gene or the presence of a dye in the membrane is untenable.

ECM dependent and integrin mediated tumor cell migration of human glioma and melanoma cell lines under serum-free conditions.

Collagen IV, laminin and fibronectin are constituents of the cerebral extracellular matrix (ECM), which is critical in glioma cell invasion. The aim of the present study was to evaluate the integrin dependent cell-matrix interactions of two tumors with different invasive properties under matrixfree conditions. Two human glioma (GaMG, U373) and melanoma (MV3, BLM) cell lines were grown in serum free medium. Immunofluorescence microscopy of collagen IV, laminin, and fibronectin was performed. The adhesion of monolayer cells and their migration out of multicellular spheroids was quantified for these ECM components. Integrin chains known to act as laminin receptors were blocked by specific antibodies in additional migration assays. All cell lines expressed all the ECM components under serum free conditions. Tumor cell adhesion and migration in both glioma and melanoma cell lines was increased by all the ECM components, laminin being the strongest promotor of migration. However, migration was dose dependent in gliomas, whereas melanomas revealed a dose optimum of 10 micrograms/ml laminin. Antibodies against alpha 3 integrins significantly reduced migration on laminin in all cell lines, anti-beta 1 in all cell lines except U373. Anti-alpha 2 in BLM showed a strong effect, anti-alpha 6 was a stronger inhibitor in glioma than in melanoma cells. Integrins are functionally involved in tumor cell locomotion on laminin. The blocking of laminin related integrin chains markedly reduces cell motility in a varying manner between the cell lines. Moreover, different cell lines utilize different integrins as the laminin receptor.

Guanidinobenzoatase and UPA in high-grade human astrocytomas and after xenografting cell suspensions into the rat cerebral cortex: proteases for metastasis and disease progression.

BACKGROUND: Invasion and metastasis is aided by the secretion of guanidinobenzoatase, that cleaves the link peptide to fibronectin, and urokinase plasminogen activator (uPA), which initiates a molecular cascade to activate plasmin and collagenases. This process permits malignant cell migration through the extracellular matrix. MATERIALS: Original human astrocytomas were examined for guanidinobenzoatase and uPA. Suspensions of high-grade human astrocytomas were xenografted into pockets in host cerebral cortex for 1-7 days. RESULTS: A class of guanidinobenzoatase positive cells was observed in the original human astrocytomas and in tumor masses formed in the implantation pocket and around blood vessels. Secondary foci containing guanidinobenzoatase positive cells formed around blood vessels and individual positive astrocytoma cells migrated on the glia limitans along parallel and intersecting nerve fiber fascicles and the corpus callosum. uPA and GFAP were colocalized with guanidinobenzoatase. CONCLUSION: The high-grade astrocytomas reestablish themselves and maintain their characteristics as a tissue although grafted as individual cells.

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.