Linezolid brain penetration in neurointensive care patients

BACKGROUND

Linezolid exposure in critically ill patients is associated with high inter-individual variability, potentially resulting in subtherapeutic antibiotic exposure. Linezolid exhibits good penetration into the CSF, but its penetration into cerebral interstitial fluid (ISF) is unknown.

OBJECTIVES

To determine linezolid penetration into CSF and cerebral ISF of neurointensive care patients.

PATIENTS AND METHODS

Five neurocritical care patients received 600 mg of linezolid IV twice daily for treatment of extracerebral infections. At steady state, blood and CSF samples were collected from arterial and ventricular catheters, and microdialysate was obtained from a cerebral intraparenchymal probe.

RESULTS

The median fAUC0-24 was 57.6 (24.9-365) mg·h/L in plasma, 64.1 (43.5-306.1) mg·h/L in CSF, and 27.0 (10.7-217.6) mg·h/L in cerebral ISF. The median penetration ratio (fAUCbrain_or_CSF/fAUCplasma) was 0.5 (0.25-0.81) for cerebral ISF and 0.92 (0.79-1) for CSF. Cerebral ISF concentrations correlated well with plasma (R = 0.93, P < 0.001) and CSF levels (R = 0.93, P < 0.001).The median fAUC0-24/MIC ratio was ≥100 in plasma and CSF for MICs of ≤0.5 mg/L, and in cerebral ISF for MICs of ≤0.25 mg/L. The median fT>MIC was ≥80% of the dosing interval in CSF for MICs of ≤0.5 mg/L, and in plasma and cerebral ISF for MICs of ≤0.25 mg/L.

CONCLUSIONS

Linezolid demonstrates a high degree of cerebral penetration, and brain concentrations correlate well with plasma and CSF levels. However, substantial variability in plasma levels, and thus cerebral concentrations, may result in subtherapeutic tissue concentrations in critically ill patients with standard dosing, necessitating therapeutic drug monitoring.

Malignant transformation of vestibular schwannoma following radiosurgery-a case report and review of the literature

Malignant transformation of vestibular schwannoma (VS) post-radiosurgery is an extremely rare but life-threatening complication. We present a patient who underwent two surgeries for a benign VS and received Gamma Knife radiosurgery for residual tumour. Five and a half years post-radiosurgery, the patient was reoperated for symptomatic recurrence of the tumour. Histopathology confirmed the diagnosis of a high-grade spindle cell sarcoma. Although near-total resection was uneventful, the patient deteriorated rapidly, and comfort care was chosen. This report is the 13th documented case of histopathologically confirmed malignant transformation of a benign VS that strictly meets the modified Cahan's criteria, suggesting the direct link to radiosurgery-induced malignancy.

An evaluation of physical and augmented patient-specific intracranial aneurysm simulators on microsurgical clipping performance and skills: a randomized controlled study

OBJECTIVE

In the era of flow diversion, there is an increasing demand to train neurosurgeons outside the operating room in safely performing clipping of unruptured intracranial aneurysms. This study introduces a clip training simulation platform for residents and aspiring cerebrovascular neurosurgeons, with the aim to visualize peri-aneurysm anatomy and train virtual clipping applications on the matching physical aneurysm cases.

METHODS

Novel, cost-efficient techniques allow the fabrication of realistic aneurysm phantom models and the additional integration of holographic augmented reality (AR) simulations. Specialists preselected suitable and unsuitable clips for each of the 5 patient-specific models, which were then used in a standardized protocol involving 9 resident participants. Participants underwent four sessions of clip applications on the models, receiving no interim training (control), a video review session (video), or a video review session and holographic clip simulation training (video + AR) between sessions 2 and 3. The study evaluated objective microsurgical skills, which included clip selection, number of clip applications, active simulation time, wrist tremor analysis during simulations, and occlusion efficacy. Aneurysm occlusions of the reference sessions were assessed by indocyanine green videoangiography, as well as conventional and photon-counting CT scans.

RESULTS

A total of 180 clipping procedures were performed without technical complications. The measurements of the active simulation times showed a 39% improvement for all participants. A median of 2 clip application attempts per case was required during the final session, with significant improvement observed in experienced residents (postgraduate year 5 or 6). Wrist tremor improved by 29% overall. The objectively assessed aneurysm occlusion rate (Raymond-Roy class 1) improved from 76% to 80% overall, even reaching 93% in the extensively trained cohort (video + AR) (p = 0.046).

CONCLUSIONS

The authors introduce a newly developed simulator training platform combining physical and holographic aneurysm clipping simulators. The development of exchangeable, aneurysm-comprising housings allows objective radio-anatomical evaluation through conventional and photon-counting CT scans. Measurable performance metrics serve to objectively document improvements in microsurgical skills and surgical confidence. Moreover, the different training levels enable a training program tailored to the cerebrovascular trainees' levels of experience and needs.

Cystic recurrence of vestibular schwannoma post-radiosurgery: an institutional experience

BACKGROUND

Stereotactic radiosurgery effectively controls vestibular schwannoma (VS). However, in certain cases, microsurgical resection may be necessary for post-radiosurgery tumour progression. The characteristics and microsurgical challenges of uncommon cystic recurrences post-radiosurgery are rarely addressed.

METHOD

We retrospectively analysed 24 consecutive patients who underwent microsurgical intervention for recurrent VS post-radiosurgery by the senior author.

RESULTS

Tumour recurrence post-radiosurgery occurred as solid growth in 19 patients (79%), while 5 patients (21%) developed large brainstem-compressing cysts. The median time interval for tumour recurrence post-radiosurgery was similar between cystic and non-cystic recurrent VS (30 vs. 25 months; p=0.08). Cystic recurrences occurred in primarily cystic VS in 3 patients, and new cysts developed in 2 patients with primarily solid VS. Intra-operatively, tumours were firm in 18 cases (75%) and strongly adhered to surrounding structures in 14 cases (58%). All cystic cases underwent cyst decompression, while complete resection of solid tumour components was avoided due to neurovascular adherence. At a mean follow-up of 42±39 months, 12 patients (50%) showed contrast-enhancing tumour residuals in follow-up imaging, including all cystic recurrent cases. Tumour residuals remained stable without requiring further intervention, except for one patient revealing malignant tumour transformation. House-Brackmann grade I/II was preserved in 15 patients (62%). Three patients (13%) developed new facial palsy, and two patients (8%) improved to House-Brackmann grade II. Cystic recurrences had a significantly higher frequency of tumour residuals compared to solid recurrences (100% vs. 37%; p=0.01) but similar rates of facial palsy (60% vs. 32%; p=0.24) CONCLUSIONS: Cyst development in VS post-radiosurgery is more common in primary cystic lesions but can also occur in rare cases of primary solid VS. Symptomatic cysts require microsurgical decompression. However, complete resection of the solid tumour component is not crucial for long-term tumour control and should be avoided if it risks neurological function in this delicate area.

The Effect of Oral Nimodipine on Cerebral Metabolism and Hemodynamic Parameters in Patients Suffering Aneurysmal Subarachnoid Hemorrhage

INTRODUCTION

Nimodipine is routinely administered to aneurysmal subarachnoid hemorrhage patients to improve functional outcomes. Nimodipine can induce marked systemic hypotension, which might impair cerebral perfusion and brain metabolism.

METHODS

Twenty-seven aneurysmal subarachnoid hemorrhage patients having multimodality neuromonitoring and oral nimodipine treatment as standard of care were included in this retrospective study. Alterations in mean arterial blood pressure (MAP), cerebral perfusion pressure (CPP), brain tissue oxygen tension (pbtO2), and brain metabolism (cerebral microdialysis), were investigated up to 120 minutes after oral administration of nimodipine (60 mg or 30 mg), using mixed linear models.

RESULTS

Three thousand four hundred twenty-five oral nimodipine administrations were investigated (126±59 administrations/patient). After 60 mg of oral nimodipine, there was an immediate statistically significant (but clinically irrelevant) drop in MAP (relative change, 0.97; P<0.001) and CPP (relative change: 0.97; P<0.001) compared with baseline, which lasted for the whole 120 minutes observation period (P<0.001). Subsequently, pbtO2 significantly decreased 50 minutes after administration (P=0.04) for the rest of the observation period; the maximum decrease was -0.6 mmHg after 100 minutes (P<0.001). None of the investigated cerebral metabolites (glucose, lactate, pyruvate, lactate/pyruvate ratio, glutamate, glycerol) changed after 60 mg nimodipine. Compared with 60 mg nimodipine, 30 mg induced a lower reduction in MAP (relative change, 1.01; P=0.02) and CPP (relative change, 1.01; P=0.03) but had similar effects on pbtO2 and cerebral metabolism (P>0.05).

CONCLUSIONS

Oral nimodipine reduced MAP, which translated into a reduction in cerebral perfusion and oxygenation. However, these changes are unlikely to be clinically relevant, as the absolute changes were minimal and did not impact cerebral metabolism.

Oxoglutarate dehydrogenase complex controls glutamate-mediated neuronal death

Brain injury is accompanied by neuroinflammation, accumulation of extracellular glutamate and mitochondrial dysfunction, all of which cause neuronal death. The aim of this study was to investigate the impact of these mechanisms on neuronal death. Patients from the neurosurgical intensive care unit suffering aneurysmal subarachnoid hemorrhage (SAH) were recruited retrospectively from a respective database. In vitro experiments were performed in rat cortex homogenate, primary dissociated neuronal cultures, B35 and NG108-15 cell lines. We employed methods including high resolution respirometry, electron spin resonance, fluorescent microscopy, kinetic determination of enzymatic activities and immunocytochemistry. We found that elevated levels of extracellular glutamate and nitric oxide (NO) metabolites correlated with poor clinical outcome in patients with SAH. In experiments using neuronal cultures we showed that the 2-oxoglutarate dehydrogenase complex (OGDHC), a key enzyme of the glutamate-dependent segment of the tricarboxylic acid (TCA) cycle, is more susceptible to the inhibition by NO than mitochondrial respiration. Inhibition of OGDHC by NO or by succinyl phosphonate (SP), a highly specific OGDHC inhibitor, caused accumulation of extracellular glutamate and neuronal death. Extracellular nitrite did not substantially contribute to this NO action. Reactivation of OGDHC by its cofactor thiamine (TH) reduced extracellular glutamate levels, Ca2+ influx into neurons and cell death rate. Salutary effect of TH against glutamate toxicity was confirmed in three different cell lines. Our data suggest that the loss of control over extracellular glutamate, as described here, rather than commonly assumed impaired energy metabolism, is the critical pathological manifestation of insufficient OGDHC activity, leading to neuronal death.

Endovascular thrombectomy with or without intravenous thrombolysis in large-vessel ischemic stroke: A non-inferiority meta-analysis of 6 randomised controlled trials

BACKGROUND

It is unclear whether thrombectomy alone is non-inferior to thrombectomy with intravenous thrombolysis in patients with acute ischemic stroke due to large-vessel occlusion.

PURPOSE

To perform a comprehensive, trial-level data, non-inferiority meta-analysis of randomised controlled trials comparing endovascular thrombectomy with and without intravenous thrombolysis in patients with ischemic stroke due to large-vessel occlusion of anterior circulation.

METHODS

The prespecified primary efficacy outcome was functional independence, defined as a modified Rankin scale (mRS)score of 0 to 2 at 90 days. The two prespecified non-inferiority margins were risk differences of -10% and - 5%. The study was registered in PROSPERO (CRD42022361110) and conducted according to PRISMA guidelines.

RESULTS

Six trials were included in this analysis (DIRECT-MT, DEVT, SKIP, MR CLEAN-NO IV, DIRECT-SAFE and SWIFT DIRECT) comprising a total of 2334 patients. Functional independence at 90 days was achieved by 570 (49·0%) of 1164 patients in the thrombectomy alone group and 595 (50·9%) of 1170 patients in the thrombectomy with thrombolysis group (pooled risk difference - 0·02, [95% CI -0·06-0·02]). Combined thrombectomy and thrombolysis were associated with significantly higher rates of successful reperfusion (pooled risk ratio 0·96 [95% CI, 0·93-0·99], p = 0·006) but at the expense of a significantly increased risk of overall - but not symptomatic - intracranial haemorrhage (pooled risk ratio 0·87 [95% CI, 0·77-0·98], p = 0·02).

CONCLUSIONS

Compared with a combined treatment approach, thrombectomy alone was non-inferior at -10% non-inferiority margin, but not at a - 5% inferiority margin for functional independence. Current evidence cannot exclude clinically important differences between the two treatment approaches.

CD34 microvascularity in low-grade glioma: correlation with 5-aminolevulinic acid fluorescence and patient prognosis in a multicenter study at three specialized centers

OBJECTIVE

Early markers are urgently needed in low-grade glioma (LGG) evaluation to rapidly estimate the individual patient's prognosis and to determine the optimal postoperative management. Generally, visible 5-aminolevulinic acid (5-ALA) fluorescence is present in only a few LGGs. Recently, the authors identified visible 5-ALA fluorescence as a powerful intraoperative marker for unfavorable outcome in LGG treatment. However, its precise histopathological correlate is unclear. Neoangiogenesis represents a crucial event in tumor evolution, and CD34 is an established marker for vascular endothelial progenitors potentially indicating tumor progression. The aim of this study was thus to correlate 5-ALA fluorescence and CD34 microvascularity as well as to investigate the prognostic value of CD34 in a large series of LGGs.

METHODS

In this retrospective study including 3 specialized centers, patients with histopathologically confirmed isocitrate dehydrogenase-mutated LGGs (WHO grade II) receiving 5-ALA prior to resection were included. During surgery, the presence of visible fluorescence was analyzed and one representative tumor sample from the area with the maximum fluorescence effect (tumor with focal fluorescence or nonfluorescing tumor) was selected for each LGG. All fluorescing or nonfluorescing tumor samples were stained for CD34 and semiquantitatively analyzed for microvascular proliferation patterns (physiological vessels, branching capillaries, or microvessel clusters) as well as automatically quantified for CD34 microvessel density (MVD) by standardized histomorphometry software. These semiquantitative/quantitative CD34 data were correlated to the fluorescence status and patient outcome including progression-free survival (PFS), malignant transformation-free survival (MTFS), and overall survival (OS).

RESULTS

In a total of 86 LGGs, visible fluorescence was found during surgery in 13 (15%) cases. First, the semiquantitative CD34 score significantly correlated with intraoperative fluorescence (p = 0.049). Accordingly, the quantitative CD34 MVD was significantly higher in tumors showing fluorescence (p = 0.03). Altogether, the semiquantitative CD34 score showed a strong correlation with quantitative CD34 MVD (p < 0.001). At a mean follow-up of 5.4 ± 2.6 years, microvessel clusters in semiquantitative analysis were a prognostic marker for poor PFS (p = 0.01) and MTFS (p = 0.006), but not OS (p = 0.28). Finally, quantitative CD34 MVD > 10 vessels/mm2 was a prognostic marker for poor PFS (p = 0.01), MTFS (p = 0.008), and OS (p = 0.049).

CONCLUSIONS

The data indicate that CD34 microvascularity is associated with intraoperative 5-ALA fluorescence and outcomes in patients with LGG. Thus, visible fluorescence in LGGs might indicate increased CD34 microvascularity, serving as an early prognostic marker for unfavorable patient outcome that is already available during surgery.

Reply to Stummer, W.; Thomas, C. Comment on "Hosmann et al. 5-ALA Fluorescence Is a Powerful Prognostic Marker during Surgery of Low-Grade Gliomas (WHO Grade II)-Experience at Two Specialized Centers. Cancers 2021, 13, 2540"

We greatly appreciate Dr. Stummer's and Dr. Thomas's interest in our study and their important comments [...].

Meropenem concentrations in brain tissue of neurointensive care patients exceed CSF levels

BACKGROUND

Inadequate antibiotic exposure in cerebral infections might have detrimental effects on clinical outcome. Commonly, antibiotic concentrations within the CSF were used to estimate cerebral target levels. However, the actual pharmacological active unbound drug concentration beyond the blood-brain barrier is unknown.

OBJECTIVES

To compare meropenem concentrations in blood, CSF and cerebral microdialysate of neurointensive care patients.

PATIENTS AND METHODS

In 12 patients suffering subarachnoid haemorrhage, 2000 mg of meropenem was administered every 8 h due to an extracerebral infection. Meropenem concentrations were determined in blood, CSF and cerebral microdialysate at steady state (n = 11) and following single-dose administration (n = 5).

RESULTS

At steady state, the free AUC0-8 was 233.2 ± 42.7 mg·h/L in plasma, 7.8 ± 1.9 mg·h/L in CSF and 26.6 ± 14.0 mg·h/L in brain tissue. The brain tissue penetration ratio (AUCbrain/AUCplasma) was 0.11 ± 0.06, which was more than 3 times higher than in CSF (0.03 ± 0.01), resulting in an AUCCSF/AUCbrain ratio of 0.41 ± 0.16 at steady state. After single-dose administration similar proportions were achieved (AUCbrain/AUCplasma = 0.09 ± 0.08; AUCCSF/AUCplasma = 0.02 ± 0.00). Brain tissue concentrations correlated well with CSF concentrations (R = 0.74, P < 0.001), but only moderately with plasma concentrations (R = 0.51, P < 0.001). Bactericidal thresholds were achieved in both plasma and brain tissue for MIC values ≤16 mg/L. In CSF, bactericidal effects were only reached for MIC values ≤1 mg/L.

CONCLUSIONS

Meropenem achieves sufficient bactericidal concentrations for the most common bacterial strains of cerebral infections in both plasma and brain tissue, even in non-inflamed brain tissue. CSF concentrations would highly underestimate the target site activity of meropenem beyond the blood-brain barrier.

Combined standard bypass and parent artery occlusion for management of giant and complex internal carotid artery aneurysms

BACKGROUND

Complex aneurysms do not have a standard protocol for treatment. In this study, we investigate the safety and efficacy of microsurgical revascularization combined with parent artery occlusion (PAO) in giant and complex internal carotid artery (ICA) aneurysms.

METHODS

Between 1998 and 2017, 41 patients with 47 giant and complex ICA aneurysms were treated by an a priori planned combined treatment strategy. Clinical and radiological outcomes were stratified according to mRS and Raymond classification. Bypass patency was assessed. Median follow-up time was 3.9 years.

RESULTS

After successful STA-MCA bypass, staged endovascular (n=37) or surgical (n=1) PAO was executed in 38 patients following a negative balloon occlusion test. Intolerance to PAO led to stent/coil treatments in two patients. Perioperative bypass patency was confirmed in 100% of completed STA-MCA bypass procedures. Long-term overall bypass patency rate was 99%. Raymond 1 occlusion and good outcome were achieved in 95% and 97% (mRS 0-2) of cases, respectively. No procedure-related mortality was encountered. Eighty-four percent of patients with preoperative cranial nerve compression syndromes improved during follow-up.

CONCLUSIONS

The combined approach of STA-MCA bypass surgery followed by parent artery occlusion achieves high aneurysm occlusion and low morbidity rates in the management of giant and complex ICA aneurysms. This combined indirect approach represents a viable alternative to flow diversion in patients with cranial nerve compression syndromes or matricidal aneurysms, and may serve as a backup strategy in cases of peri-interventional complications or lack of suitable endovascular access.

Quantitative analysis of human brain microdialysate for target site pharmacokinetics of major anesthetics ketamine, midazolam and propofol

Brain microdialysis samples of intensive care patients treated with the essential anesthetics ketamine, midazolam and propofol were investigated. Importantly, despite decades of clinical use, comprehensive human cerebral pharmacokinetic data of these drugs is still missing. To encounter this apparent lack of knowledge, we combined cerebral microdialysis with leading-edge analytical instrumentation to monitor the neurochemistry of living human patients. For the quantitative analysis, high performing analytical approaches were developed that can handle minute sample volumes and possible ultralow target analyte levels. The developed methods provided detection limits below 100 ng L^-1 for all target analytes and high precision (below 4% RSD intraday). Methods were linear between LODs and 100 μg L^-1 for ketamine, 75 μg L^-1 for midazolam and 10 μg L^-1 for propofol respectively, with coefficients of determination R²≥ 0.999. Further, being aware of the error-prone and demanding translation of microdialysis levels to interstitial concentrations, in vitro approaches for recovery testing of microdialysis probes as well as internal normalization approaches were conducted. Thus, we herein report the first cerebral pharmacokinetic data of ketamine, midazolam and propofol determined in microdialysis samples of 15 neurointensive care patients. We could prove blood-brain barrier penetration of all of the investigated anesthetics and could correlate applied dosages and actual brain exposition of ketamine. However, we emphasize the need of an expanded prospective study including individual microdialysis recovery testing as well as matched serum and/or cerebrospinal fluid collection for a more comprehensive cerebral pharmacokinetic understanding.

Infiltrative gliomas of the thalamus in children: the role of surgery in the era of H3 K27M mutant midline gliomas

Background

The role of surgery in the management of pediatric non-pilocytic infiltrative thalamic gliomas needs to be revisited specifically with regard to molecularly defined subtypes.

Methods

A retrospective review of a consecutive series of children operated on a thalamic tumor between 1992 and May 2018 was performed. Neuroimaging data were reviewed for localization and extent of resection; pathology was re-reviewed according to the current WHO classification, including assessment of histone H3 K27 mutational status.

Results

Forty-nine patients with a thalamic tumor aged < 18 years at diagnosis were identified. Twenty-five patients (51%) had a non-pilocytic infiltrative glioma, of which the H3 K27M status was available in 22. Fourteen patients were diagnosed as diffuse midline glioma (DMG) H3 K27M mutant. There was no statistically significant difference in survival between patients harboring the H3 K27M mutation and wildtype. Resection (“any resection > 50%” vs “biopsy”) and histological tumor grade (“°II” vs “°III+°IV”) were statistically significant predictors of survival (univariate: p = 0.044 and p = 0.013, respectively). These results remained significant on multivariate analysis (HR 0.371/p = 0.048, HR 9.433/p = 0.035).

Conclusion

We advocate to still consider an attempt at maximal safe resection in the multidisciplinary treatment of unilateral thalamic non-pilocytic gliomas irrespective of their H3 K27-mutational status.

5-ALA Fluorescence Is a Powerful Prognostic Marker during Surgery of Low-Grade Gliomas (WHO Grade II)-Experience at Two Specialized Centers

The prediction of the individual prognosis of low-grade glioma (LGG) patients is limited in routine clinical practice. Nowadays, 5-aminolevulinic acid (5-ALA) fluorescence is primarily applied for improved intraoperative visualization of high-grade gliomas. However, visible fluorescence is also observed in rare cases despite LGG histopathology and might be an indicator for aggressive tumor behavior. The aim of this study was thus to investigate the value of intraoperative 5-ALA fluorescence for prognosis in LGG patients. We performed a retrospective analysis of patients with newly diagnosed histopathologically confirmed LGG and preoperative 5-ALA administration at two independent specialized centers. In this cohort, we correlated the visible intraoperative fluorescence status with progression-free survival (PFS), malignant transformation-free survival (MTFS) and overall survival (OS). Altogether, visible fluorescence was detected in 7 (12%) of 59 included patients in focal intratumoral areas. At a mean follow-up time of 5.3 ± 2.9 years, patients with fluorescing LGG had significantly shorter PFS (2.3 ± 0.7 vs. 5.0 ± 0.4 years; p = 0.01), MTFS (3.9 ± 0.7 vs. 8.0 ± 0.6 years; p = 0.03), and OS (5.4 ± 1.0 vs. 10.3 ± 0.5 years; p = 0.01) than non-fluorescing tumors. Our data indicate that visible 5-ALA fluorescence during surgery of pure LGG might be an already intraoperatively available marker of unfavorable patient outcome and thus close imaging follow-up might be considered.

How to predict the consistency and vascularity of meningiomas by MRI: an institutional experience

OBJECTIVE

In surgery for meningiomas tumor location and extension is currently the only MRI characteristic used to predict the feasibility and difficulty of the resection. Key surgical tumor characteristics such as consistency and vascularity remain obscured until the tumor is exposed. We therefore aimed to identify MRI sequences able to predict these crucial meningioma features.

METHODS

We retrospectively reviewed our imaging database on cranial meningiomas and correlated MRI T2W, T1W, and FLAIR images with the consistency and vascularity reported by the surgeon in the operative notes. The reported consistency was classified into three grades [°I (soft) to °III (hard)]. Vascularity was grouped into little (°I) versus strong (°II). MRI signal intensity (SI) ratios were calculated with ROIs in the meningioma, the buccinator muscle and the frontal white matter.

RESULTS

Of the 172 reviewed patients, 44 met the strict inclusion criteria with respect to the quality of the OR notes. The included meningiomas were located at the convexity (11/44), falcine (3/44), skull base (14/44), and posterior fossa (16/44). Twenty-four meningiomas (54.5%) were classified as consistency grade (°)I, seven (15.9%) °II, and thirteen (29.5%) °III. The grade of vascularization was little in 12 and strong in 14. The higher the ratio on T2W images the softer (p = 0.020) and the more vascularized (p = 0.001) the tumor presented.

DISCUSSION

T2W MR images may be helpful to characterize meningiomas with regard to the expected consistency and grade of vascularization.

Detrimental effects of intrahospital transport on cerebral metabolism in patients suffering severe aneurysmal subarachnoid hemorrhage

OBJECTIVE

Intrahospital transport for CT scans is routinely performed for neurosurgical patients. Particularly in the sedated and mechanically ventilated patient, intracranial hypertension and blood pressure fluctuations that might impair cerebral perfusion are frequently observed during these interventions. This study quantifies the impact of intrahospital patient transport on multimodality monitoring measurements, with a particular focus on cerebral metabolism.

METHODS

Forty intrahospital transports in 20 consecutive patients suffering severe aneurysmal subarachnoid hemorrhage (SAH) under continuous intracranial pressure (ICP), brain tissue oxygen tension (pbtO2), and cerebral microdialysis monitoring were prospectively included. Changes in multimodality neuromonitoring data during intrahospital transport to the CT scanner and the subsequent 10 hours were evaluated using linear mixed models. Furthermore, the impact of risk factors at transportation, such as cerebral vasospasm, cerebral hypoxia (pbtO2 < 15 mm Hg), metabolic crisis (lactate-pyruvate ratio [LPR] > 40), and transport duration on cerebral metabolism, was analyzed.

RESULTS

During the transport, the mean ICP significantly increased from 7.1 ± 3.9 mm Hg to 13.5 ± 6.0 mm Hg (p < 0.001). The ICP exceeded 20 mm Hg in 92.5% of patients; pbtO2 showed a parallel rise from 23.1 ± 13.3 mm Hg to 28.5 ± 23.6 mm Hg (p = 0.02) due to an increase in the fraction of inspired oxygen during the transport. Both ICP and pbtO2 returned to baseline values thereafter. Cerebral glycerol significantly increased from 71.0 ± 54.9 µmol/L to 75.3 ± 56.0 µmol/L during the transport (p = 0.01) and remained elevated for the following 9 hours. In contrast, cerebral pyruvate and lactate levels were stable during the transport but showed a significant secondary increase 1-8 hours and 2-9 hours, respectively, thereafter (p < 0.05). However, the LPR remained stable over the entire observation period. Patients with extended transport duration (more than 25 minutes) were found to have significantly higher levels of cerebral pyruvate and lactate as well as lower glutamate concentrations in the posttransport period.

CONCLUSIONS

Intrahospital transport and horizontal positioning during CT scans induce immediate intracranial hypertension and an increase in cerebral glycerol, suggesting neuronal injury. Afterward, sustained impairment of neuronal metabolism for several hours could be observed, which might increase the risk of secondary ischemic events. Therefore, intrahospital transport for neuroradiological imaging should be strongly reconsidered and only indicated if the expected benefit of imaging results outweighs the risks of transportation.

The Impact of Intra-Arterial Papaverine-Hydrochloride on Cerebral Metabolism and Oxygenation for Treatment of Delayed-Onset Post-Subarachnoid Hemorrhage Vasospasm

BACKGROUND

Delayed posthemorrhagic vasospasm remains among the major complications after aneurysmal subarachnoid hemorrhage (SAH) and can result in devastating ischemic strokes. As rescue therapy, neurointerventional procedures are used for selective vasodilatation.

OBJECTIVE

To investigate the effects of intra-arterial papaverine-hydrochloride on cerebral metabolism and oxygenation.

METHODS

A total of 10 consecutive patients, suffering from severe aneurysmal SAH were prospectively included. Patients were under continuous multimodality neuromonitoring and required intra-arterial papaverine-hydrochloride for vasospasm unresponsive to hypertensive therapy. Cerebral metabolism (microdialysis), brain tissue oxygen tension (ptiO2), intracranial pressure (ICP), and cerebral perfusion pressure (CPP) were analyzed for a period of 12 h following intervention.

RESULTS

A median dose of 125 mg papaverine-hydrochloride was administered ipsilateral to the multimodality probe. Angiographic improvement of cerebral vasospasm was observed in 80% of patients. During intervention, a significant elevation of ICP (13.7 ± 5.2 mmHg) and the lactate-pyruvate ratio (LPR) (54.2 ± 15.5) was observed, whereas a decrease in cerebral glucose (0.9 ± 0.5 mmol/L) occurred. Within an hour, an increase of cerebral lactate (5.0 ± 2.0 mmol/L) and glycerol (104.4 ± 89.8 μmol/L) as well as a decrease of glucose (0.9 ± 0.4 mmol/L) were measured. In 2 to 5 h after treatment, the LPR significantly decreased (pretreatment: 39.3 ± 15.3, to lowest 30.5 ± 6.7). Cerebral pyruvate levels increased in 1 to 10 h (pretreatment: 100.1 ± 33.1 μmol/L, to highest 141.4 ± 33.7 μmol/L) after intervention. No significant changes in ptiO2 or CPP occurred.

CONCLUSION

The initial detrimental effects of the endovascular procedure itself were outweighed by an improved cerebral metabolism within 10 h thereafter. As the effect was very limited, repeated interventions or continuous application should be considered.

Cerebral nitric oxide and mitochondrial function in patients suffering aneurysmal subarachnoid hemorrhage-a translational approach

Background

Cerebral ischemia and neuroinflammation following aneurysmal subarachnoid hemorrhage (SAH) are major contributors to poor neurological outcome. Our study set out to investigate in an exploratory approach the interaction between NO and energy metabolism following SAH as both hypoxia and inflammation are known to affect nitric oxide (NO) metabolism and NO in turn affects mitochondria.

Methods

In seven patients under continuous multimodality neuromonitoring suffering poor-grade aneurysmal SAH, cerebral metabolism and NO levels (determined as a sum of nitrite plus nitrate) were determined in cerebral microdialysate for 14 days following SAH. In additional ex vivo experiments, rat cortex homogenate was subjected to the NO concentrations determined in SAH patients to test whether these NO concentrations impair mitochondrial function (determined by means of high-resolution respirometry).

Results

NO levels showed biphasic kinetics with drastically increased levels during the first 7 days (74.5 ± 29.9 μM) and significantly lower levels thereafter (47.5 ± 18.7 μM; p = 0.02). Only during the first 7 days, NO levels showed a strong negative correlation with brain tissue oxygen tension (r = − 0.78; p < 0.001) and a positive correlation with cerebral lactate (r = 0.79; p < 0.001), pyruvate (r = 0.68; p < 0.001), glutamate (r = 0.65; p < 0.001), as well as the lactate-pyruvate ratio (r = 0.48; p = 0.01), suggesting mitochondrial dysfunction. Ex vivo experiments confirmed that the increase in NO levels determined in patients during the acute phase is sufficient to impair mitochondrial function (p < 0.001). Mitochondrial respiration was inhibited irrespectively of whether glutamate (substrate of complex I) or succinate (substrate of complex II) was used as mitochondrial substrate suggesting the inhibition of mitochondrial complex IV. The latter was confirmed by direct determination of complex IV activity.

Conclusions

Exploratory analysis of our data suggests that during the acute phase of SAH, NO plays a key role in the neuronal damage impairing mitochondrial function and facilitating accumulation of mitochondrial substrate; further studies are required to understand mechanisms underlying this observation.

Towards ultrahigh resolution OCT based endoscopical pituitary gland and adenoma screening: a performance parameter evaluation

Ultrahigh resolution optical coherence tomography (UHR-OCT) for differentiating pituitary gland versus adenoma tissue has been investigated for the first time, indicating more than 80% accuracy. For biomarker identification, OCT images of paraffin embedded tissue are correlated to histopathological slices. The identified biomarkers are verified on fresh biopsies. Additionally, an approach, based on resolution modified UHR-OCT ex vivo data, investigating optical performance parameters for the realization in an in vivo endoscope is presented and evaluated. The identified morphological features-cell groups with reticulin framework-detectable with UHR-OCT showcase a promising differentiation ability, encouraging endoscopic OCT probe development for in vivo application.

Optimizing MR imaging for intraoperative image guidance in sellar pathologies

PURPOSE

With the advancement of extended endonasal approaches, the ability to surgically reach parasellar tumor extensions increase. The aim of the study was to propose an optimized imaging protocol for surgical guidance in the cavernous sinus (CS) for proper visualization structures at risk.

METHODS

Prospective case control analysis of 20 consecutive pituitary adenoma patients scheduled for endoscopic transnasal surgery. Assessment of the capability of three different MRI sequences (MPRAGE, VIBE, CISS) by 4 investigators to correctly visualize sellar and parasellar structures. Invasiveness and position of the normal pituitary gland were compared with the intraoperative findings.

RESULTS

The consensus between the 4 examiners to achieve the same results for all modalities was 40% for MPRAGE, 70% for VIBE and 60% for CISS sequences (p = 0.155). A consensus of Knosp Grade per patient was 80% for MPRAGE, 100% for VIBE and 90% for CISS (overall kappa 0.60). A higher Knosp Grade was found in MPRAGE sequences compared to the other sequences. Intraoperative status of invasiveness was correctly identified in 12/20 (60%) with MPRAGE, 19/20 (95%) with VIBE and 11/20 (55%) with CISS sequences. The position of the normal pituitary gland was most frequent evaluable in 15/20 (75%) and correctly identified in 12/15 (80%) cases.

CONCLUSION

Our data showed that VIBE sequences obtain the highest degree of consensus with intraoperative findings of invasiveness and position of the normal pituitary gland. VIBE sequences, due to their high spatial resolution and at the same time fast image acquisition could provide improved imaging for neuronavigation.

The impact of implant material and patient age on the long-term outcome of secondary cranioplasty following decompressive craniectomy for severe traumatic brain injury

Background

Secondary cranioplasty (CP) is considered to support the neurological recovery of patients after decompressive craniectomy (DC), but the treatment success might be limited by complications associated to confounders, which are not yet fully characterized. The aim of this study was to identify the most relevant factors based on the necessity to perform revision surgeries.

Methods

Data from 156 patients who received secondary CP following DC for severe traumatic brain injury (TBI) between 1984 and 2015 have been retrospectively analyzed and arranged into cohorts according to the occurrence of complications requiring surgical intervention.

Results

Cox regression analysis revealed a lower revision rate in patients with polymethylmethacrylate (PMMA) implants than in patients with autologous calvarial bone (ACB) implants (HR 0.2, 95% CI 0.1 to 1.0, p = 0.04). A similar effect could be observed in the population of patients aged between 18 and 65 years, who had a lower risk to suffer complications requiring surgical treatment than individuals aged under 18 or over 65 years (HR 0.4, 95% CI 0.2 to 0.9, p = 0.02). Revision rates were not influenced by the gender (p = 0.88), timing of the CP (p = 0.53), the severity of the TBI (p = 0.86), or the size of the cranial defect (p = 0.16).

Conclusions

In this study, the implant material and patient age were identified as the most relevant parameters independently predicting the long-term outcome of secondary CP. The use of PMMA was associated with lower revision rates than ACB and might provide a therapeutic benefit for selected patients with traumatic cranial defects.

Electronic supplementary material

The online version of this article (10.1007/s00701-020-04243-7) contains supplementary material, which is available to authorized users.

High Interobserver Agreement in the Subjective Classification of 5-Aminolevulinic Acid Fluorescence Levels in Newly Diagnosed Glioblastomas

BACKGROUND AND OBJECTIVES

Fluorescence-guided resection of glioblastomas (GBM) using 5-aminolevulinic acid (5-ALA) improves intraoperative tumor visualization and is thus widely used nowadays. During resection, different fluorescence levels can usually be distinguished within the same tumor. Recently, we demonstrated that strong, vague, and no fluorescence correspond to distinct histopathological characteristics in newly diagnosed GBM. However, the qualitative fluorescence classification by the neurosurgeon is subjective and currently no comprehensive data on interobserver variability is available. The aim of this study was thus to investigate the interobserver variability in the classification of 5-ALA fluorescence levels in newly diagnosed GBM.

STUDY DESIGN/MATERIALS AND METHODS

A questionnaire investigating the interobserver variability in 5-ALA fluorescence quantification was performed at a nation-wide neurosurgical oncology meeting. The participants involved in the neurosurgical/neurooncological field were asked to categorize 30 cases of 5-ALA fluorescence images derived from GBM resection on a lecture hall screen according to the widely used three-tier fluorescence classification scheme (negative, vague, or strong fluorescence). Additionally, participants were asked for information on their medical background such as specialty, level of training, and experience with 5-ALA fluorescence-guided procedures. Interobserver agreement was defined as the calculated mean κ values for each observer.

RESULTS

A total of 36 questionnaires were included in the final analysis. The mean average κ value in fluorescence classification within the entire cohort was 0.71 ± 0.12 and 29 (81%) participants had a substantial or almost perfect interobserver agreement (κ values 0.6-1.0). Interobserver agreement was significantly higher in neurosurgeons (mean κ: 0.83) as compared with non-neurosurgeons involved in the neurooncological field (mean κ: 0.52; P < 0.001). Furthermore, interobserver agreement was significantly higher in participants who had experience with at least 25 5-ALA fluorescence-guided surgeries (mean κ: 0.87) compared with less experienced colleagues (mean κ: 0.82; P = 0.039).

CONCLUSION

Our study found a high interobserver agreement in the qualitative classification of different 5-ALA fluorescence levels in newly diagnosed GBM. Interobserver agreement increases significantly in more experienced participants and therefore a high level of experience is crucial for reliable intraoperative fluorescence classification. Lasers Surg. Med. © 2020 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals, Inc.

Endogenous arterial blood pressure increase after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Spontaneous blood pressure rise is a frequently observed phenomenon following aneurysmal subarachnoid hemorrhage (SAH). Facing the risk of aneurysmal rebleeding and the occurrence of delayed cerebral ischemia it is unclear how to react to these endogenous-driven blood pressure changes, as their predictive value for clinical course and functional outcome is still unknown.

PATIENTS AND METHODS

Endogenous blood pressure characteristics within 21 days after SAH were retrospectively analyzed in 93 patients. Any use of vasopressors for active induction of hypertension marked the end of data collection. Mean arterial blood pressure (MAP) was related to the onset of cerebral vasospasm and patient characteristics (Hunt&Hess, age, pre-existing hypertension, antihypertensive therapy, sedation). Predictors for cerebral infarction and functional outcome were calculated using a logistic regression model.

RESULTS

A significant MAP increase was observed in all patients from day 3 to day 7. Patients developing cerebral vasospasm had an overall steeper increase of MAP during this period (11.1 ± 11.4 mmHg vs. 6.5 ± 8.9 mmHg, p = 0.04). MAP rise started already 3 days before detection of vasospasm. Lower MAP values were recorded in patients with poor Hunt&Hess grade, under sedation and thus in patients with poor outcome. MAP had no impact on the development of cerebral infarction. In univariate analysis MAP on day 5 (OR 0.95, 95 %-CI: 0.89-0.99), MAP on day 6 (OR 0.95, 95 %-CI: 0.91-1.00), Hunt&Hess grade (OR 1.72, 95 %-CI: 1.14-2.60), sedation (OR 17.04, 95 %-CI: 2.08-139.51) and stroke (OR 5.82, 95 %-CI: 1.63-20.82) were predictors for poor outcome. In multivariable analysis, only sedation (OR 13.72, 95 %-CI: 1.62-115.94) and ischemic stroke (OR 4.48, 95 %-CI: 1.16-17.31) remained significant.

CONCLUSION

Spontaneous MAP increase occured in all patients following SAH. It was highly influenced by clinical parameters, thereby limiting its prognostic value for functional outcome. However, a steep increase of MAP might be an early clinical marker to identify patients at risk for developing cerebral vasospasm.

Cerebrospinal fluid disturbances after transcallosal surgery: incidence and predictive factors

OBJECTIVE

CSF dynamics after transcallosal resection of intraventricular lesions can be altered, and the need for shunt implantation complicates the management of these patients. Because the pathophysiological mechanism and contributing factors are poorly understood and the incidence has largely not been described, the authors conducted a study to elucidate these factors.

METHODS

The authors retrospectively reviewed data from patients who had been operated on at their institution via a transcallosal approach between March 2002 and December 2016. They evaluated the need for a shunt implantation up to 3 months after surgery by assessing clinical variables. These variables were age at surgery, the need for perioperative external CSF drainage, histology of the lesion, and the following radiological parameters: pre- and postoperative Evans index, maximal postoperative extension of subdural effusions (SDEs) measured on axial images, and maximal interhemispheric fissure (IHF) width measured on coronal images assessed at 4 different points in time (preoperatively, day 1, days 2-4, and days 4-8 after surgery). To identify potential risk factors, univariate and multivariate regression models were constructed. Receiver operating characteristic (ROC) curves for significant predictors, as well as the area under the curve (AUC), were calculated.

RESULTS

Seventy-four patients (40 female and 34 male) were identified; their median age at surgery was 17.6 years (range 4 months to 76 years). Shunt implantation was necessary in 13 patients (ventriculoperitoneal [VP] shunt, n = 7; subdural peritoneal [SDP] shunt, n = 6) after a median interval of 24 days (range 10 days to 3 months). Univariate logistic regression models revealed a significant effect of IHF width on days 4-8 (OR 1.31, 95% CI 1.03-1.66; p = 0.027), extension of SDE on days 2-4 (OR 1.33, 95% CI 1.11-1 0.60; p = 0.003), and age (OR 0.932, 95% CI 0.88-0.99; p = 0.02). In the multiple regression model, the effect of the independent variable extension of the SDE remained significant. ROC curves for the predictors IHF width on days 4-8 and extension of SDE on days 2-4 revealed an AUC equal to 0.732 and 0.752, respectively. Before shunt implantation, the ventricles were smaller compared to the preoperative size in 9 of the 13 patients (SDP shunt, n = 5; VP shunt, n = 4).

CONCLUSIONS

The rate of shunt-dependent hydrocephalus 3 months after surgery in this heterogeneous group of patients was 17.6% (95% CI 9.7%-28.2%). The authors identified as predictive factors the variables extension of the convexity space, IHF 1 week after surgery, and younger age.

An advanced protocol for intraoperative visualization of sinunasal structures: experiences from pituitary surgery

OBJECTIVE

The transsphenoidal route to pituitary adenomas challenges surgeons because of the highly variable sinunasal anatomy. Orientation may be improved if the appropriate information is provided intraoperatively by image guidance. The authors developed an advanced image guidance protocol dedicated to sinunasal surgery that extracts information from multiple modalities and forms it into a single image that includes fine sinunasal structures and arteries.The aim of this study was to compare the advantages of this novel image guidance protocol with the authors' previous series, with emphasis on anatomical structures visualized and complication rate.

METHODS

This retrospective analysis comprised 200 patients who underwent surgery for pituitary adenoma via a transnasal transsphenoidal endoscopic approach. The authors' standard image guidance protocol consisting of CT for solid bone, T1CEMRI for soft tissues, and MRA for the carotid artery was applied in 100 consecutive cases. The advanced image guidance protocol added a first-hit ray casting of the CT scan for visualization of fine sinunasal structures, and adjustments to the MRA to visualize the sphenopalatine artery (SPA) were applied in a subsequent 100 consecutive cases.

RESULTS

A patent sphenoid ostium-i.e., an ostium not covered by a mucosal layer-was visualized significantly more often by the advanced protocol than the standard protocol (89% vs 40%, p < 0.001) in primary surgeries. The SPA and its branches were only visualized by the advanced protocol (87% and 91% of cases in primary surgeries and reoperations, respectively) and not once by the standard protocol. The number of visualized complete and incomplete sphenoid septations matched significantly more commonly with the surgical view when using the advanced protocol than the standard protocol at primary operation (mean 1.9 vs 1.6, p < 0.001). However, in 25% of all cases a complex and not a simple sinus anatomy was present. In comparison with the intraoperative results, a complex sphenoid sinus anatomy was always detected by the advanced but not by the standard protocol (25% vs 8.5%, p = 0.001).Furthermore, application of the advanced protocol reduced the cumulative rate of complications (25% vs 18% [standard vs advanced group]). Although an overall significant difference could not be determined (p = 0.228), a subgroup analysis of reoperations (35/200) revealed a significantly lower rate of complications in the advanced group (5% vs 30%, p = 0.028).

CONCLUSIONS

The data show that the advanced image guidance protocol could intraoperatively visualize the fine sinunasal sinus structures and small arteries with a high degree of detail. By improving intraoperative orientation, this may help to reduce the rate of complications in endoscopic transsphenoidal surgery, especially in reoperations.

Management of choroid plexus tumors-an institutional experience

Background

Choroid plexus tumors are rare entities. Resection is the mainstay of treatment in grade I and grade II tumors and adjuvant treatment is usually reserved for the less frequent choroid plexus carcinoma (CPC). Outcome is not only related to their histological grade but also dependent on their size, location, and presence of often multifactorial disturbances of cerebrospinal fluid (CSF) circulation.

Methods

Retrospective analysis of 36 consecutive patients operated on a choroid plexus tumor at our institution in a mixed pediatric and adult population between 1991 and 2016.

Results

Twenty-one CPP, 11 atypical choroid plexus papillomas (aCPP), and four CPC were encountered in 17 children and 19 adults. Regardless of histological grading, gross-total resection (GTR) could be achieved in 91.7% of patients. Tumor recurrence (25.0%) was significantly associated with histological grading (p = 0.004), subtotal resection (p = 0.002), and intraoperatively evident zones of tumor infiltration (p = 0.001). Adjuvant therapy was performed in 19.4% of patients, mainly diagnosed with CPC. The 5-year overall survival rate was 95.2% for CPP and 100.0% for both aCPP and CPC. Survival was related to the extent of resection (p = 0.001), tumor progression (p = 0.04), and the presence of leptomeningeal metastases (p = 0.002). Even after resection, either ventricular or subdural shunting was required in 25.0% of patients.

Conclusions

We could confirm that GTR is crucial for treatment of choroid plexus tumors. Parenchymal tumor infiltration as detected intraoperatively was associated with the extent of resection and not limited to CPC. CSF disturbances mandating treatment may persist after resection.

Multiple Pituitary Apoplexy-Cavernous Sinus Invasion as Major Risk Factor for Recurrent Hemorrhage

OBJECTIVE

Pituitary apoplexy is a rare but potentially life-threatening disorder that occurs in up to 10% of adenomas. Whereas risk factors for the initial hemorrhagic event are well described, there is minor knowledge on clinical symptomatic recurrent pituitary apoplexies.

METHODS

At the Medical University of Vienna, 76 patients were surgically treated for clinical symptomatic pituitary apoplexy between 1990 and 2017. Four patients (5.3%) suffered multiple pituitary apoplexies after initial surgery. In this retrospective study, neuroradiologic images, clinical data, and intraoperative findings were reviewed for potential risk factors of multiple apoplexies in pituitary adenomas.

RESULTS

Patients with multiple apoplexies had significantly higher Knosp grading on preoperative imaging (median grade 4), and more frequently observed cavernous sinus invasion intraoperatively (P = 0.01). Consequently, all cases with multiple pituitary apoplexies remained with residual adenoma postoperatively. In cases of residual tumor within the cavernous sinus, recurrent apoplexy occurred in 23.5% of patients. A tumor recurrence/residual was resected significantly earlier in patients with single apoplexy (median 2.2 years) than in patients with multiple apoplexies (median 5.4 years; P = 0.05). Multiple pituitary apoplexies caused significantly greater rates of ophthalmoplegia (75% vs. 14.1%; P = 0.01) and long-term hormone-replacement therapy was necessary in all cases.

CONCLUSIONS

Cavernous sinus invasion and subtotal resection are high risk factors for multiple apoplexies in pituitary adenomas. Early treatment is recommended for residual tumor in the cavernous sinus to minimize the risk of recurrent apoplexy with subsequent worse clinical outcome.

Intra-Arterial Papaverine-Hydrochloride and Transluminal Balloon Angioplasty for Neurointerventional Management of Delayed-Onset Post-Aneurysmal Subarachnoid Hemorrhage Vasospasm

OBJECTIVE

After subarachnoid hemorrhage, delayed onset vasospasm can result in devastating ischemic stroke. The phenomenon of delayed cerebral ischemia (DCI) is not yet fully understood, and the correlation of angiographic vasospasm and cerebral infarction is still unclear. Therefore, we investigated the effect of endovascular treatment on the angiographic response and occurrence of DCI.

METHODS

Eighty patients with subarachnoid hemorrhage and serious cerebral vasospasm underwent endovascular treatment using intra-arterial papaverine-hydrochloride (IAP) or transluminal balloon angioplasty (TBA). The angiographic response and infarction rate were classified using the pre- and postinterventional angiographic images and computed tomography scans.

RESULTS

In 90% of patients, vasospasm could be improved. In most cases (78.8%), IAP was used. Retreatment after IAP was necessary in 32.9% of patients but never after TBA. A total of 233 vascular territories were treated in 128 procedures. Angiographic improvement was observed in 66.5% of territories, which was significantly associated with early intervention (P = 0.02), the use of TBA (P = 0.01), and the dose of papaverine-hydrochloride (P = 0.01). DCI occurred in 47.5% of the patients. Territorial infarction was associated with a poor Hunt and Hess grade (P = 0.03), day of aneurysm treatment (P = 0.01), severe vasospasm before (P = 0.02) and after (P = 0.03) treatment, and number of interventions (P = 0.01). However, the infarction rate was independent of the angiographic response.

CONCLUSION

The discrepancy of excellent angiographic results and the high incidence of DCI might stem from an inaccurate or a delayed diagnosis of impending ischemia. In view of the limited time window, optimized peri-interventional management and continuous cerebral multimodality neuromonitoring might be crucial for the ideal timing of endovascular procedures to prevent cerebral infarctions.

Multimodality Management of Vein of Galen Malformations-An Institutional Experience

BACKGROUND

The vein of Galen aneurysmal malformation (VGM) is a rare intracranial arteriovenous fistula with a dramatic manifestation during infancy and 100% mortality without treatment. Therapeutic strategies for VGMs have changed over time as a result of advances in endovascular techniques. We present our experience and multimodality approach within the last 4 decades.

METHODS

A retrospective analysis and angiographic review were performed of patients with VGM between 1975 and 2016 at our institution.

RESULTS

Eighteen consecutive patients were identified, including 10 with choroidal and 8 with mural VGMs. In 37 endovascular interventions, a transarterial approach was mostly performed (82.8%). One patient was initially treated surgically and received 2 Gamma Knife treatments after multiple embolizations. The preferred embolization agent was histoacryl for choroidal VGMs and a combination of coils and histoacryl for mural VGMs. Total occlusion was achieved in 87.5% of mural VGMs and 11.1% of choroidal VGMs. Cerebral hemorrhages and infarction occurred only in patients younger than 1 month. At a median follow-up interval of 4.6 years, good outcome was achieved in 53.8% and poor outcome in 46.2%, with an overall mortality of 16.7%. Poor outcome was significantly associated with choroidal-type VGMs, age <1 month at first embolization, and incomplete occlusion.

CONCLUSIONS

Endovascular embolization using a transarterial approach is the therapy of choice. Gamma Knife radiosurgery can be considered as second-line therapy in a multimodal approach. Whereas treatment within the first month of life is associated with the highest mortality and complications, we did not detect any severe adverse events thereafter.

Applicability of NeuroTrend as a bedside monitor in the neuro ICU

OBJECTIVE

To assess whether ICU caregivers can correctly read and interpret continuous EEG (cEEG) data displayed with the computer algorithm NeuroTrend (NT) with the main attention on seizure detection and determination of sedation depth.

METHODS

120 screenshots of NT (480h of cEEG) were rated by 18 briefly trained nurses and biomedical analysts. Multirater agreements (MRA) as well as interrater agreements (IRA) compared to an expert opinion (EXO) were calculated for items such as pattern type, pattern location, interruption of recording, seizure suspicion, consistency of frequency, seizure tendency and level of sedation.

RESULTS

MRA as well as IRA were almost perfect (80-100%) for interruption of recording, spike-and-waves, rhythmic delta activity and burst suppression. A substantial agreement (60-80%) was found for electrographic seizure patterns, periodic discharges and seizure suspicion. Except for pattern localization (70.83-92.26%), items requiring a precondition and especially those who needed interpretation like consistency of frequency (47.47-79.15%) or level of sedation (41.10%) showed lower agreements.

CONCLUSIONS

The present study demonstrates that NT might be a useful bedside monitor in cases of subclinical seizures. Determination of correct sedation depth by ICU caregivers requires a more detailed training.

SIGNIFICANCE

Computer algorithms may reduce the workload of cEEG analysis in ICU patients.