Microsurgical Creation of Giant Bifurcation Aneurysms in Rabbits for the Evaluation of Endovascular Devices

Giant aneurysms are dangerous lesions requiring endovascular treatment, with high rates of aneurysm recanalization and re-rupture. Reliable in vivo models are rare but are required for testing new endovascular devices. We demonstrate the technical aspects of the creation of giant bifurcation aneurysms in New Zealand white rabbits (2.5-5.5 kg). A 25-30 mm long venous pouch is taken from the external jugular vein, and a bifurcation between both carotid arteries is created microsurgically. The pouch is sutured in the bifurcation to mimic a giant aneurysm. This protocol summarizes our previously published standard technique for venous pouch true arterial bifurcation aneurysms and highlights its essential modification steps for giant aneurysms. Using this modified technique, we were able to create an animal model for giant aneurysms with high comparability to humans regarding the hemodynamics and coagulation systems. Furthermore, low morbidity and high aneurysm patency rates were achieved. The proposed giant aneurysm model offers an excellent possibility for testing new endovascular devices.

Network topology in brain tumor patients with and without structural epilepsy: a prospective MEG study

Background

It was proposed that network topology is altered in brain tumor patients. However, there is no consensus on the pattern of these changes and evidence on potential drivers is lacking.

Objectives

We aimed to characterize neurooncological patients' network topology by analyzing glial brain tumors (GBTs) and brain metastases (BMs) with respect to the presence of structural epilepsy.

Methods

Network topology derived from resting state magnetoencephalography was compared between (1) patients and controls, (2) GBTs and BMs, and (3) patients with (PSEs) and without structural epilepsy (PNSEs). Eligible patients were investigated from February 2019 to March 2021. We calculated whole brain (WB) connectivity in six frequency bands, network topological parameters (node degree, average shortest path length, local clustering coefficient) and performed a stratification, where differences in power were identified. For data analysis, we used Fieldtrip, Brain Connectivity MATLAB toolboxes, and in-house built scripts.

Results

We included 41 patients (21 men), with a mean age of 60.1 years (range 23-82), of those were: GBTs (n = 23), BMs (n = 14), and other histologies (n = 4). Statistical analysis revealed a significantly decreased WB node degree in patients versus controls in every frequency range at the corrected level (p1-30Hz = 0.002, pγ = 0.002, pβ = 0.002, pα = 0.002, pθ = 0.024, and pδ = 0.002). At the descriptive level, we found a significant augmentation for WB local clustering coefficient (p1-30Hz = 0.031, pδ = 0.013) in patients compared to controls, which did not persist the false discovery rate correction. No differences regarding networks of GBTs compared to BMs were identified. However, we found a significant increase in WB local clustering coefficient (pθ = 0.048) and decrease in WB node degree (pα = 0.039) in PSEs versus PNSEs at the uncorrected level.

Conclusion

Our data suggest that network topology is altered in brain tumor patients. Histology per se might not, however, tumor-related epilepsy seems to influence the brain's functional network. Longitudinal studies and analysis of possible confounders are required to substantiate these findings.

European survey on neurosurgical management of primary central nervous system lymphomas and preoperative corticosteroid therapy

Introduction

Preoperative corticosteroid therapy (CST) is common in primary central nervous system lymphoma (PCNSL) and may complicate histopathological diagnosis. There is an ongoing debate on the best management after preoperative CST.

Research question

We aimed to survey how different European neurosurgical units treat PCNSL patients after preoperative CST.

Methods

An English-language survey consisting of 21 questions addressing the management of patients with suspected PCNSL and preoperative CST was sent to European hospitals. The survey also included three clinical cases to assess the decision-making process in a clinical setting.

Results

The survey was completed by 74 European hospitals. There was no clear consensus on how to treat a patient with PCNSL after CST. Accordingly, 24.3% responded that they would generally defer surgery regardless of a possible radiological response, 47.3% would defer surgery only if there is regression in preoperative MRI and the remaining 28.4% would defer surgery only if the tumor had completely vanished. Furthermore, there were distinct discrepancies in responses of neurosurgical units regarding their general management approach and their case-based decision in the three example cases. The results of our survey also showed regional differences and differences in treatment decisions between high-, intermediate- and low-volume centers.

Discussion and conclusion

There was no clear consensus on how to treat patients with suspected PCNSL and preoperative CST. Furthermore, most centers also showed inconsistencies in their responses regarding their general approach as well as individual patient treatment. More high-quality evidence-based recommendations are needed to improve consensus and thus patient care.

The importance of additional intracranial injuries in epidural hematomas: detailed clinical analysis, long-term outcome, and literature review in surgically managed epidural hematomas

Objective

Epidural hematomas (EDH) occur in up to 8.2% of all traumatic brain injury patients, with more than half needing surgical treatment. In most patients suffering from this perilous disease, good recovery with an excellent clinical course is possible. However, the clinical course is mainly dependent on the presence of additional intracerebral injuries. Few studies comparing isolated and combined EDH in detail exist.

Methods

We performed a retrospective single-center study from April 2002 to December 2014. The mean follow-up time was more than 6 years. In addition to analyzing diverse clinicoradiological data, we performed a systematic literature review dealing with a detailed comparison of patients with (combined) and without (isolated) additional intracerebral injuries.

Results

We included 72 patients in the study. With increasing age, combined EDH had a higher incidence than isolated EDH. The mortality rate of the patients in the cohort was 10%, of which 0% had isolated EDH and 10% had combined EDH. Good recovery was achieved in 69% of patients, of which 91% had isolated EDH and 50% had combined EDH. A subgroup analysis of the different additional intracerebral injuries in combined EDH demonstrated no significant difference in outcome. A systematic literature review only identified six studies. Patients with isolated EDH had a statistically significantly lower mortality risk [relative risk (RR): 0.22; 95% CI: 0.12-0.39] and a statistically significantly lower risk of unfavorable Glasgow outcome scale score (RR: 0.21; 95% CI: 0.14-0.31) than patients with combined EDH.

Conclusions

An excellent outcome in patients with surgically treated isolated EDH is possible. Furthermore, patients with combined EDH or isolated EDH with a low Glasgow coma scale (GCS) score may have favorable outcomes in 50% of the cases. Therefore, every possible effort for treatment should be made for this potentially lethal injury.

Radiomic features define risk and are linked to DNA methylation attributes in primary CNS lymphoma

Background

The prognostic roles of clinical and laboratory markers have been exploited to model risk in patients with primary CNS lymphoma, but these approaches do not fully explain the observed variation in outcome. To date, neuroimaging or molecular information is not used. The aim of this study was to determine the utility of radiomic features to capture clinically relevant phenotypes, and to link those to molecular profiles for enhanced risk stratification.

Methods

In this retrospective study, we investigated 133 patients across 9 sites in Austria (2005-2018) and an external validation site in South Korea (44 patients, 2013-2016). We used T1-weighted contrast-enhanced MRI and an L1-norm regularized Cox proportional hazard model to derive a radiomic risk score. We integrated radiomic features with DNA methylation profiles using machine learning-based prediction, and validated the most relevant biological associations in tissues and cell lines.

Results

The radiomic risk score, consisting of 20 mostly textural features, was a strong and independent predictor of survival (multivariate hazard ratio = 6.56 [3.64-11.81]) that remained valid in the external validation cohort. Radiomic features captured gene regulatory differences such as in BCL6 binding activity, which was put forth as testable treatment target for a subset of patients.

Conclusions

The radiomic risk score was a robust and complementary predictor of survival and reflected characteristics in underlying DNA methylation patterns. Leveraging imaging phenotypes to assess risk and inform epigenetic treatment targets provides a concept on which to advance prognostic modeling and precision therapy for this aggressive cancer.

P01.08.A Perioperative Levetiracetam for seizure prophylaxis in seizure naive brain tumor patients with focus on neurocognitive functioning

Background

In seizure-naive brain tumor patients, the efficacy of perioperative prophylactic antiepileptic drugtreatment remains controversial. In case of administration, the common preferred drug is levetiracetam (LEV) because of its favorable pharmacological profile. Research to date has not sufficiently determined how LEV affects cognition in the short term as it does in the perioperative period. The objective of this prospective study was to examine the neurocognitive functioning of seizure-naive brain tumor patients after receiving LEV perioperatively.

Material and methods

Patients with supratentorial brain tumor undergoing surgery received LEV three days before until seven days after surgery as seizure prophylaxis. Cognitive functioning (NeuroCogFX), LEV plasma-levels, hematotoxicity, side-effects, as well as health-related quality of life (HRQoL, Qolie31), were recorded preoperatively before (Baseline) and after onset of LEV (Pre-Op), 4-6 days postoperatively (Post-Op) and 21 days postoperatively (Follow-Up).

Results

No significant changes in cognitive functioning and HRQoL were seen after onset of preoperative LEV. There was a significant improvement of NeuroCogFX total-score at Follow-Up (p=0.004) compared to Baseline. The overall-score Qolie31 showed simultaneous improvement patterns as cognitive functioning (p< 0.001). The most frequent side effect related to study drug was somnolence (in 24% of patients).

Conclusion

Following LEV therapy, a significant improvement of cognitive functioning, as well as an improvement in HRQoL, were detected postoperatively. This is presumably due to the debulking effect of the surgery. Nevertheless, LEV has no detrimental effect on cognitivefunctioning in the perioperative phase in seizure-naive brain tumor patients.

Current trends and outcomes of non-elective neurosurgical care in Central Europe during the second year of the COVID-19 pandemic

Reflecting the first wave COVID-19 pandemic in Central Europe (i.e. March 16th–April 15th, 2020) the neurosurgical community witnessed a general diminution in the incidence of emergency neurosurgical cases, which was impelled by a reduced number of traumatic brain injuries (TBI), spine conditions, and chronic subdural hematomas (CSDH). This appeared to be associated with restrictions imposed on mobility within countries but also to possible delayed patient introduction and interdisciplinary medical counseling. In response to one year of COVID-19 experience, also mapping the third wave of COVID-19 in 2021 (i.e. March 16 to April 15, 2021), we aimed to reevaluate the current prevalence and outcomes for emergency non-elective neurosurgical cases in COVID-19-negative patients across Austria and the Czech Republic. The primary analysis was focused on incidence and 30-day mortality in emergency neurosurgical cases compared to four preceding years (2017–2020). A total of 5077 neurosurgical emergency cases were reviewed. The year 2021 compared to the years 2017–2019 was not significantly related to any increased odds of 30 day mortality in Austria or in the Czech Republic. Recently, there was a significant propensity toward increased incidence rates of emergency non-elective neurosurgical cases during the third COVID-19 pandemic wave in Austria, driven by their lower incidence during the first COVID-19 wave in 2020. Selected neurosurgical conditions commonly associated with traumatic etiologies including TBI, and CSDH roughly reverted to similar incidence rates from the previous non-COVID-19 years. Further resisting the major deleterious effects of the continuing COVID-19 pandemic, it is edifying to notice that the neurosurgical community´s demeanor to the recent third pandemic culmination keeps the very high standards of non-elective neurosurgical care alongside with low periprocedural morbidity. This also reflects the current state of health care quality in the Czech Republic and Austria.

Perioperative levetiracetam for seizure prophylaxis in seizure-naive brain tumor patients with focus on neurocognitive functioning

Introduction

In seizure-naive brain tumor patients, the efficacy of perioperative prophylactic antiepileptic drug treatment remains controversial. In case of administration, the common preferred drug is levetiracetam (LEV) because of its favorable pharmacological profile. Research to date has not sufficiently determined how LEV affects cognition in the short term, as is the case in the perioperative period. The objective of this prospective study was to examine the neurocognitive functioning of seizure-naive brain tumor patients after receiving LEV perioperatively.

Methods

Fortythree patients with supratentorial brain tumor scheduled for surgery received LEV three days before until six days after surgery as seizure prophylaxis. Cognitive functioning (NeuroCogFX), LEV plasma-levels, hematotoxicity, side-effects, as well as health-related quality of life (HRQoL, Qolie31), were recorded preoperatively before (Baseline) and after onset of LEV (Pre-Op), 4–6 days postoperatively (Post-Op) and 21 days postoperatively (Follow-Up).

Results

No significant changes in cognitive functioning and HRQoL were seen after onset of preoperative LEV. There was a significant improvement of NeuroCogFX total-score at Follow-Up (p = 0.004) compared to Baseline. The overall-score Qolie31 showed simultaneous improvement patterns as cognitive functioning (p < 0.001). The most frequent side effect related to study drug was somnolence (in 28.6% of patients).

Conclusions

A significant improvement of cognitive functioning, as well as an improvement in HRQoL, were detected postoperatively. This is presumably due to the debulking effect of the surgery. Nevertheless, LEV has no detrimental effect on cognitive functioning in the perioperative phase in seizure-naive brain tumor patients.

Trial registration

This study was registered prospectively (Date: 25/11/2015; EudraCT: 2015–003,916-19).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02762-7.

An Update on Neurosurgical Management of Primary CNS Lymphoma in Immunocompetent Patients

Primary central nervous system lymphomas (PCNSL) are rare CNS tumors that harbor a conspicuously longer diagnostic delay compared to other malignant brain tumors. The gold standard for diagnosis is stereotactic biopsy to acquire tissue for histopathological analysis and therefore neurosurgery plays a central role when reducing the diagnostic period is mandated. However, histopathological diagnosis could be complicated if the patient was preoperatively exposed to corticosteroids. Besides the histopathological result, diagnosis of a PCNSL also requires full diagnostic workup to exclude cerebral metastatic disease of a systemic lymphoma. Most reviews of PCNSL discuss recent advancements in systemic treatment options from an (neuro-)oncologic viewpoint, whereas our intention was to discuss the optimization of the diagnostic period and therefore describe current standards of imaging, summarizing the diagnostic workup, discussing the surgical workup and future diagnostic prospects as well as the influence of preoperative corticosteroid therapy to reduce the diagnostic delay of PCNSL patients.

The meningioma surface factor: a novel approach to quantify shape irregularity on preoperative imaging and its correlation with WHO grade

OBJECTIVE

Atypical and anaplastic meningiomas account for 20% of all meningiomas. An irregular tumor shape on preoperative MRI has been associated with WHO grade II-III histology. However, this subjective allocation does not allow quantification or comparison. An objective parameter of irregularity could substantially influence resection strategy toward a more aggressive approach. Therefore, the aim of this study was to objectively quantify the level of irregularity on preoperative MRI and predict histology based on WHO grade using this novel approach.

METHODS

A retrospective study on meningiomas resected between January 2010 and December 2018 was conducted at two neurosurgical centers. This novel approach relies on the theory that a regularly shaped tumor has a smaller surface area than an irregularly shaped tumor with the same volume. A factor was generated using the surface area of a corresponding sphere as a reference, because for a given volume a sphere represents the shape with the smallest surface area possible. Consequently, the surface factor (SF) was calculated by dividing the surface area of a sphere with the same volume as the tumor with the surface area of the tumor. The resulting value of the SF ranges from > 0 to 1. Finally, the SF of each meningioma was then correlated with the corresponding histopathological grading.

RESULTS

A total of 126 patients were included in this study; 60.3% had a WHO grade I, 34.9% a WHO grade II, and 4.8% a WHO grade III meningioma. Calculation of the SF demonstrated a significant difference in SFs between WHO grade I (SF 0.851) and WHO grade II-III meningiomas (SF 0.788) (p < 0.001). Multivariate analysis identified SF as an independent prognostic factor for WHO grade (OR 0.000009, 95% CI 0.000-0.159; p = 0.020).

CONCLUSIONS

The SF is a proposed mathematical model for a quantitative and objective measurement of meningioma shape, instead of the present subjective assessment. This study revealed significant differences between the SFs of WHO grade I and WHO grade II-III meningiomas and demonstrated that SF is an independent prognostic factor for WHO grade.

Nerve root herniation with entrapment in the facet joint gap after lumbar decompression surgery: a case presentation

Background

An incidental dural tear is a well-known complication during spine surgery. A rare consequence is a postoperative nerve root herniation. The purpose of this report is to describe a case of such a herniation with entrapment in the facet gap joint and to present the first MR images of this rare surgical complication.

Case presentation

We report a case of a patient who underwent lumbar decompression surgery and afterwards suffered a sudden intractable sciatica. Postoperative MRI showed a new facet joint gap effusion. During revision surgery an entrapped nerve root was found in the facet joint gap. In retrospective, the herniated nerve root is visible on postoperative MRI.

Conclusion

This case report highlights a rare complication during spine surgery. This finding is important as signs suggestive for nerve root herniation can easily be overlooked on MRI. Furthermore, this represents the first MRI documentation of this complication.

Microsurgical and endovascular treatment of un-ruptured cerebral aneurysms by European hybrid neurosurgeons to balance surgical skills and medical staff management

Background

In Europe, aneurysm treatment performed by dually trained neurosurgeons is extremely scarce. We provide outcome data for un-ruptured aneurysm patients treated at a European hybrid center to prove that hybrid neurosurgeons achieve clinical and angiographical results allowing to integrate hybrid neurosurgery into routine aneurysm treatment. This will not only help to maintain neurovascular microsurgical skills but will influence staff costs in related hospitals.

Methods

We retrospectively analyzed all consecutively treated un-ruptured aneurysm patients between 2000 and 2016. The decision-making took into account the pros and cons of both modalities and considered patient and aneurysm characteristics. Clinical outcome was assessed by the modified Rankin scale (mRS). Occlusion rates were stratified into grade I for 100%, grade II for 99–90%, and grade III for <90% occlusion. To account for the introduction of stents, two treatment periods (p1, 2000 to 2008; p2, 2009 to 2016) were defined.

Results

The study population consisted of 274 patients (median age 55 years) harboring 338 un-ruptured aneurysms. Microsurgery (MS) was performed in 51.8% and endovascular therapy (EVT) in 43.1%; 5.1% required combined treatment. Overall, 93% showed a favorable clinical outcome (mRS 0–2), 94.3% after MS and 91.5% after EVT. Grade I aneurysm occlusion was achieved in 82.6% patients, 91.9% after MS and 72.9% after EVT. Procedure-related complications occurred after MS in 5.6% and after EVT in 4.4% patients. Mortality was recorded for five (1.8%) patients, one patient after MS and four after EVT. For the EVT cohort, significant improvement from p1 to p2 was seen with clinical outcomes (P=0.030, RR = 0.905, CI: 0.8351–0.9802) and occlusion rates (P=0.039, RR = 0.6790, CI: 0.499–0.923).

Conclusion

Hybrid neurosurgeons achieve qualified clinical and angiographic results. Dual training will allow to maintain neurovascular caseloads and preserve future aneurysm treatment within neurosurgery. Furthermore economic benefits could be observed in hospital management.

Sex-Specific Differences in Primary CNS Lymphoma

Sex-specific differences have been increasingly recognized in many human diseases including brain cancer, namely glioblastoma. Primary CNS lymphoma (PCNSL) is an exceedingly rare type of brain cancer that tends to have a higher incidence and worse outcomes in male patients. Yet, relatively little is known about the reasons that contribute to these observed sex-specific differences. Using a population-representative cohort of patients with PCNSL with dense magnetic resonance (MR) imaging and digital pathology annotation (n = 74), we performed sex-specific cluster and survival analyses to explore possible associations. We found three prognostically relevant clusters for females and two for males, characterized by differences in (i) patient demographics, (ii) tumor-associated immune response, and (iii) MR imaging phenotypes. Upon a multivariable analysis, an enhanced FoxP3+ lymphocyte-driven immune response was associated with a shorter overall survival particularly in female patients (HR 1.65, p = 0.035), while an increased extent of contrast enhancement emerged as an adverse predictor of outcomes in male patients (HR 1.05, p < 0.01). In conclusion, we found divergent prognostic constellations between female and male patients with PCNSL that suggest differential roles of tumor-associated immune response and MR imaging phenotypes. Our results further underline the importance of continued sex-specific analyses in the field of brain cancer.

Subarachnoid hemorrhage in rats - Visualizing blood distribution in vivo using gadolinium-enhanced magnetic resonance imaging: Technical note

BACKGROUND

The aims of this study were to assess the feasibility of magnetic resonance imaging (MRI) to track the in vivo distribution of autologous, injected blood in a subarachnoid hemorrhage model (SAH), and to evaluate whether this technique results in observable morphological detriment.

NEW METHOD

We used an SAH model of stereotactic injection of autologous blood into the prechiasmatic cistern in Sprague Dawley rats. To visualize its in vivo distribution, a gadolinium-containing contrast agent was added to the autologous blood prior to injection. MRI was performed on a 9.4 T Bruker Biospec scanner preoperatively, as well as at variable time points between 30 min to 23 days after SAH. T1-weighted and diffusion-weighted images were acquired. The morphological examination was completed by a histopathological work-up.

RESULTS

Upon injection of contrast agent-enriched autologous blood, enhancement was observed in the entire subarachnoid space within 30 min of injection. Total clearance was noted at the first postoperative day. SAH induction did not result in changes in clinical scores or on histopathological or radiological images.

COMPARISON WITH EXISTING METHODS

We modified an established method to allow in vivo MRI monitoring of subarachnoid blood distribution in an SAH model.

CONCLUSION

This technique could be used to evaluate the distribution of blood components during the development of novel SAH models. Since no additional morphological detriment was observed, this technique could be used as a validation tool to verify correct application and induction in preclinical SAH models.

Economic Comparison Between Endovascular Coiling vs Neurosurgical Clipping for Ruptured and Unruptured Intracranial Aneurysms in Austria

INTRODUCTION

Subarachnoid hemorrhage from a ruptured intracranial aneurysm poses a significant health hazard due to its high rates of mortality and disability. The 2 most commonly used treatment modalities of intracranial aneurysms are neurosurgical clipping and endovascular coiling. Through the decision on which treatment option should be chosen in every case is made based on medical indication, nevertheless, due to high socioeconomic burden of subarachnoid hemorrhage, it is also important to compare the healthcare expenditures, caused by clipping and coiling.

METHODS

A comparison of treatment costs of clipping, coiling and stent-assisted coiling (SAC) of ruptured and unruptured aneurysms in Austria was performed. We considered costs of surgery, diagnostic imaging, postoperative in-hospital care, treatment of the complications and initial rehabilitation. Cost-related data was provided by Vienna General Hospital. The length of hospital stay, complications and mortality rates were obtained from previous studies. Based on this information, a decision tree was built.

RESULTS

Surgery costs of coiling were significantly higher compared to clipping (13.303 98 Euro for Coiling and 24.847 63 Euro for SAC vs 6.835 23 Euro for Clipping). The main cost-driving factors were implants costs. However, clipping caused higher costs of in-hospital stay and initial rehabilitation. Altogether, when considering all in-hospital costs and the cost of rehabilitation treatment, the difference in costs of aneurysm clipping vs coiling was less pronounced.

CONCLUSION

This study is the first attempt to calculate the costs of aneurysm treatment in Austria. However, the economic comparison is partially based on estimations.

New mechanical thrombectomy model in the rabbit: A feasibility study

BACKGROUND AND PURPOSE

Thrombolytic therapy represented the gold standard for the treatment of ischemic stroke. Its drawbacks include increased bleeding risk and low recanalization rates. Mechanical thrombectomy is a new promising therapy option. Devices used for this procedure were substantially improved during recent years. New devices require extensive preclinical invivo testing. We therefore sought to translate the commonly used pig model to a simplified and cheaper rabbit model.

MATERIALS AND METHODS

We performed thromboembolisation in eight intubated and sedated adult female New Zealand white rabbits. The thrombus was created by careful rotation of autologous blood in a silicone tube and addition of barium sulfate for radiopacity. We injected the artificial thrombus via a catheter through the cannulated femoral artery. After thromboembolisation, 2D-DSA was performed to evaluate location and thrombus dimensions.

COMPARISON WITH EXISITING METHOD(S)

None.

RESULTS

No complications or mortality were observed in our series. In seven cases (87.5%) the location of the thromboembolism was the maxillary artery and in one case (12.5%) the thrombus reached the occipital artery. The radiopaque thrombus had a length of 7.0±4.55mm invivo. Vessel diameters in angiographic evaluation were 2.44±0.21mm for the common carotid artery and 2.1±0.16mm for the maxillary artery.

CONCLUSIONS

The novel small animal model for mechanical thrombectomy in rabbit is technically feasible and cheap. It offers comparable vessel diameters to cranial arteries and closely mimics human coagulation system.

Very large and giant microsurgical bifurcation aneurysms in rabbits: Proof of feasibility and comparability using computational fluid dynamics and biomechanical testing

BACKGROUND

Giant aneurysms are challenging lesions with unacceptable high rates of aneurysm recanalization and rerupture following embolization. Reliable in vivo models are urgently needed to test the performance of new more efficient endovascular devices.

MATERIALS AND METHODS

Aneurysms were created in 11 New Zealand white rabbits (4.5-5.5kg): A long venous pouch (length 25-30mm) mimicking the aneurysm sac was derived from the external jugular vein and sutured into a microsurgically created bifurcation between both common carotid arteries. After 4 weeks the rabbits underwent 3T Magnetic resonance angiography (3T-MRA). Exemplary computational fluid dynamics (CFD) simulations were performed to compare the flow conditions of giant rabbit and human aneurysms. We used species-related boundary conditions, in particular, we measured blood viscosity values. Biaxial mechanical tests were performed for the mechanical characterization and comparison.

COMPARISON WITH EXISITING METHOD(S)

None.

RESULTS

No peri- or postoperative mortality was observed. 3T-MRA showed aneurysm patency in 10 out of 11 aneurysms (90.9%). Aneurysm lengths ranged from 21.5-25.6mm and aneurysm necks from 7.3-9.8mm. CFD showed complex flow profiles with multiple vortices in both, rabbit and human aneurysms. Lower blood viscosity values of the rabbit (3.92mPas vs. human 5.34mPas) resulted in considerable lower wall shear stress rates (rabbit 0.38Pa vs. human 1.66Pa). Mechanical tests showed lower stiffness of rabbit aneurysms compared to unruptured human aneurysms.

CONCLUSIONS

The proposed model showed favorable aneurysm patency rates, low morbidity and good hemodynamic comparability with complex flow patterns. Biomechanical testing suggests that experimental aneurysms might be even more fragile compared to human aneurysms.

Computerized Angiographic Occlusion Rating for Ruptured Clipped Aneurysms is Superior to Subjective Occlusion Rating

BACKGROUND AND PURPOSE

The computerized occlusion rating to estimate angiographic occlusion of embolized aneurysms is superior to the subjective occlusion rating. In this study, we compared the 2 methods in the analysis of aneurysms clipped after subarachnoid hemorrhage.

MATERIALS AND METHODS

The pre- and postoperative angiographic images (DSA) of 95 selected patients were analyzed and stratified in 4 grades (grade 0 for 100%, grade I for <99%-90%, grade II for <89%-70%, grade III for <70% occlusion) by using the subjective (angiographic) occlusion rating and the computerized (angiographic) occlusion rating. For the subjective occlusion rating, the occlusion rate was estimated; for the computerized occlusion rating, the "occluded" and "nonoccluded" aneurysm areas were automatically calculated in square millimeters after outlining the ideal occlusion line.

RESULTS

With the subjective occlusion rating, 75 (78.9%), 12 (12.6%), 7 (7.4%), and 1 (1.1%) and with the computerized occlusion rating 45 (47.4%), 24 (25.3%), 20 (21.0%), and 6 (6.3%) patients had aneurysms stratified to grades 0, I, II and III, respectively. The interobserver variation was significant with the subjective occlusion rating but not with the computerized occlusion rating. The subjective occlusion rating overestimated aneurysm occlusion in 30 (31.6%) patients. Mean values were the following: subjective occlusion rating of 97.5 ± 6.3% and computerized occlusion rating of 93.5 ± 9.7%; P = < .001. No patient rebled, and 4 patients underwent retreatment during 36 ± 38.9 months; the predictive value (log-rank, Kaplan-Meier) of the subjective and computerized occlusion ratings with respect to retreatment was highly significant for both methods (subjective occlusion rating: χ(2), 29.65; P < .001; computerized occlusion rating: χ(2), 35.57, P < .001).

CONCLUSIONS

The 2 methods showed remarkable differences in the estimation of the angiographic occlusion rates of clipped aneurysms. The clearly lower interobserver variation of the computerized versus subjective occlusion rating may indicate a superiority of the computerized occlusion rating.

The secretome of apoptotic human peripheral blood mononuclear cells attenuates secondary damage following spinal cord injury in rats

After spinal cord injury (SCI), secondary damage caused by oxidative stress, inflammation, and ischemia leads to neurological deterioration. In recent years, therapeutic approaches to trauma have focused on modulating this secondary cascade. There is increasing evidence that the success of cell-based SCI therapy is due mainly to secreted factors rather than to cell implantation per se. This study investigated peripheral blood mononuclear cells as a source of factors for secretome- (MNC-secretome-) based therapy. Specifically, we investigated whether MNC-secretome had therapeutic effects in a rat SCI contusion model and its possible underlying mechanisms. Rats treated with MNC-secretome showed substantially improved functional recovery, attenuated cavity formation, and reduced acute axonal injury compared to control animals. Histological evaluation revealed higher vascular density in the spinal cords of treated animals. Immunohistochemistry showed that MNC-secretome treatment increased the recruitment of CD68(+) cells with concomitant reduction of oxidative stress as reflected by lower expression of inducible nitric oxide synthase. Notably, MNC-secretome showed angiogenic properties ex vivo in aortic rings and spinal cord tissue, and experiments showed that the angiogenic potential of MNC-secretome may be regulated by CXCL-1 upregulation in vivo. Moreover, systemic application of MNC-secretome activated the ERK1/2 pathway in the spinal cord. Taken together, these results indicate that factors in MNC-secretome can mitigate the pathophysiological processes of secondary damage after SCI and improve functional outcomes in rats.

Repeated combined endovascular therapy with milrinone and nimodipine for the treatment of severe vasospasm: preliminary results

BACKGROUND

Delayed vasospasm (VSP) following aneurysmal subarachnoid hemorrhage (aSAH) remains a major source of morbidity. Milrinone was recently suggested as an invasive VSP treatment option. It is a phosphodiesterase III inhibitor with vasodilating and additional positive inotrope and anti-inflammatory effects.

METHODS

In this preliminary series, we included patients with severe VSP and unsuccessful maximum conservative therapy. Inclusion criteria were (1) transcranial Doppler (TCD) mean >180 cm/s; (2) increase of >50 % of TCD mean values within 6 h to values >150 cm/s; and/or (3) neurological deterioration (after exclusion of hemorrhage, hydrocephalus, and other systemic reasons). Patients received endovascular therapy with nimodipine 2 mg followed by milrinone 4-8 mg. Reinterventions were indicated aggressively in cases of persistent neurological deficits or persistent high mean TCD >180 cm/s.

RESULTS

Of 121 consecutive aSAH patients, 16 (13.2 %) received endovascular VSP therapy. Of these, 11 patients (68.5 %) received ≥ 3 interventions (median 4; maximum 9); 14 (87.5 %) showed postinterventional angiographic improvement of vessel diameters; and 11 (68.5 %) showed improvement of their neurological deficits after a mean follow-up time of 4.5 months. No cardiovascular adverse events attributed to milrinone were observed.

CONCLUSIONS

Milrinone may be a useful supplementary substance for endovascular VSP therapy. Aggressive reintervention indications did not cause additional adverse events.

Evaluation of cerebral aneurysm wall thickness in experimental aneurysms: comparison of 3T-MR imaging with direct microscopic measurements

BACKGROUND

Thin aneurysm wall thickness (AWT) is thought to portend an elevated risk of intracranial aneurysm rupture. Magnetic resonance imaging (MRI) is biased by AWT overestimations. Previously, this suspected bias has been qualitatively described but never quantified. We aimed to quantify the overestimation of AWT by MRI when compared to the gold standard of AWT as measured by light microscopy of fresh aneurysm specimens (without any embedding procedure). This analysis should help to define the clinical potential of MRI estimates of AWT.

METHODS

3-Tesla (3T) MRI (contrast-enhanced T1 Flash sequences; resolution: 0.4 x 0.4 x 1.5 mm(3)) was performed in 13 experimental aneurysms. After MR acquisition, the aneurysms were retrieved, longitudinally sectioned and calibrated micrographs were obtained immediately. AWT at the dome, AWT at the neck and parent vessel wall thickness (PVT) were measured on precisely correlated MR-images and histologic micrographs by blinded independent investigators. Parameters were statistically compared (Wilcoxon test, Spearman's correlation).

RESULTS

AWT was assessed and reliably measured using MRI. Interobserver variability was not significant for either method. MR overestimation was only significant below the image resolution threshold: AWT at the dome (0.24 ± 0.06 mm vs. MR 0.30 ± 0.08 mm; p = 0.0078; R = 0.6125), AWT at the neck (0.25 ± 0.07 mm vs. MR 0.29 ± 0.07 mm; p = 0.0469; R = 0.7451), PVT (0.46 ± 0.06 mm vs. MR 0.48 ± 0.06 mm; p = 0.5; R = 0.8568).

CONCLUSION

In this experimental setting, MR overestimations were minimal (mean 0.02 mm) above the image resolution threshold. When AWT is classified in ranges defined by the MR resolution threshold, clinical usage may be beneficial. Further quantitative and comparative experimental and human studies are warranted to confirm these findings.

Computerized occlusion rating of embolized ruptured intracranial aneurysms: relation to intra- and postinterventional aneurysm rehemorrhage

Endovascular coil occlusion of ruptured cerebral aneurysms has a higher rate of rebleeding compared to surgical clipping. Initial aneurysm coil occlusion rate (OR) is the strongest available predictor of aneurysm rebleeding. Standard clinical subjective occlusion rating (SOR) is limited by subjective bias. Therefore, computerized occlusion rating (COR) was introduced. Its superiority was established for experimental and human aneurysms. In the present clinical study, we aimed to evaluate COR as a risk factor for postprocedural reruptures (PPRs) and intraprocedural reruptures (IPRs). In our series of 249 consecutive patients treated in our institution, we observed 7 (2.8%) cases with IPR and 7 (2.8%) cases with PPR. These patients were analyzed in the present study. Mean COR value was 85% (range 71-96%). In 12 (85.7%) cases, COR was lower than SOR. In aneurysms with a COR of 95% or higher, no PPR occurred. All patients with IPR harbored multiple aneurysms. In -conclusion, our data showed a distinct tendency of potentially dangerous overestimations when using SOR compared to the objectively measured COR values. IPR was always associated with multiple aneurysms.

Three-dimensional susceptibility-weighted imaging at 7 T using fractal-based quantitative analysis to grade gliomas

INTRODUCTION

Susceptibility-weighted imaging (SWI) with high- and ultra-high-field magnetic resonance is a very helpful tool for evaluating brain gliomas and intratumoral structures, including microvasculature. Here, we test whether objective quantification of intratumoral SWI patterns by applying fractal analysis can offer reliable indexes capable of differentiating glial tumor grades.

METHODS

Thirty-six patients affected by brain gliomas (grades II-IV, according to the WHO classification system) underwent MRI at 7 T using a SWI protocol. All images were collected and analyzed by applying a computer-aided fractal image analysis, which applies the fractal dimension as a measure of geometrical complexity of intratumoral SWI patterns. The results were subsequently statistically correlated to the histopathological tumor grade.

RESULTS

The mean value of the fractal dimension of the intratumoral SWI patterns was 2.086 ± 0.413. We found a trend of higher fractal dimension values in groups of higher histologic grade. The values ranged from a mean value of 1.682 ± 0.278 for grade II gliomas to 2.247 ± 0.358 for grade IV gliomas (p = 0.013); there was an overall statistically significant difference between histopathological groups.

CONCLUSION

The present study confirms that SWI at 7 T is a useful method for detecting intratumoral vascular architecture of brain gliomas and that SWI pattern quantification by means of fractal dimension offers a potential objective morphometric image biomarker of tumor grade.

Long-term patency of complex bilobular, bisaccular, and broad-neck aneurysms in the rabbit microsurgical venous pouch bifurcation model

OBJECTIVES

In experimental aneurysm models, long-term patency without spontaneous thrombosis is the most important precondition for analyses of embolization devices. We recently reported the feasibility of creating complex venous pouch bifurcation aneurysms in the rabbit with low morbidity, low mortality, and high short-term aneurysm patency. In order to further evaluate our model, we examined the long-term patency rate.

METHODS

Various sizes of complex bilobular, bisaccular, and broad-neck venous pouch aneurysms were surgically formed at an artificially created bifurcation of both common carotid arteries in 17 rabbits. Early aggressive anticoagulation was continued for 1 month. The rabbits were followed up using contrast-enhanced three-dimensional 1.5-T magnetic resonance angiography (CE-3D-MRA) at 1 month and up to 1 year after creation of the bifurcation.

RESULTS

At 1-month follow-up, all but one of the created aneurysms and all parent vessels proved to be patent. Three animals (18%) were lost during follow-up for reasons unrelated to aneurysm surgery. At 1-year follow-up, one animal showed partial and one complete spontaneous aneurysm thrombosis (aneurysm patency rate: 86%). Six out of 42 parent vessels were occluded at that time (vessel patency rate: 86%).

CONCLUSIONS

Complex bilobular, bisaccular, and broad-neck microsurgical aneurysm formation in the rabbit bifurcation model demonstrates a high long-term patency rate but is complicated by high rates of unrelated procedural mortality and morbidity. There is no need for prolonged (>4 weeks) anticoagulation to achieve good long-term patency in complex venous pouch bifurcation aneurysms.

Computerized occlusion rating: a superior predictor of aneurysm rebleeding for ruptured embolized aneurysms

BACKGROUND AND PURPOSE

The initial angiographic occlusion rate is the strongest predictor of later rebleeding in previously ruptured coil-embolized cerebral aneurysms. Angiographic estimations of aneurysmal occlusion rates are, however, subjective in nature and confounded by methodologic problems. COR has been developed, and its superiority has been experimentally established to overcome subjective bias. The purpose of this study was to assess the clinical value of COR as a more objective predictor of aneurysm rebleeding when compared with SOR as described in the Raymond Classification.

MATERIALS AND METHODS

We applied COR in a consecutive series of 249 patients. Two DSA projections were selected independently by 2 blinded investigators. In cases of disagreement on the selected projections, a consensus decision was obtained. SOR were determined by 2 independent observers according to the Raymond classification. COR was measured by 2 blinded investigators. Interobserver variations were determined for SOR and COR. COR results were compared with SOR results and stratified as 100%, 99.9%-90%, 89.9%-70%, and <70% occlusion. SOR and COR were evaluated as predictors for aneurysm rebleeding.

RESULTS

Seven aneurysms rebled (2.8%; follow-up, 59 ± 35 months). In 20.9% of all cases, DSA selection was performed by consensus evaluations. Interobserver variations were statistically significant for SOR (P = .0030) but not for COR (P = .3517). Compared with COR, SOR overestimated the degree of aneurysmal occlusion in 81.9% of all cases. Only COR predicted rebleeding (P = .0162).

CONCLUSIONS

Unacceptable interobserver variations were shown for the standard SOR estimations. COR substantially reduced the impact of subjective bias. COR may, therefore, serve as an easily applicable more objective predictor of aneurysm rerupture. The remaining bias of COR, caused by 2D image analysis, may be overcome by use of direct 3D measurements.

3D computerized occlusion rating of embolized experimental aneurysms using noninvasive 1.5T MR imaging

BACKGROUND AND PURPOSE

For embolized cerebral aneurysms, the initial occlusion rate is the most powerful parameter to predict aneurysm rerupture and recanalization. However, the occlusion rate is only estimated subjectively in clinical routine. To minimize subjective bias, computer occlusion-rating (COR) was successfully validated for 2D images. To minimize the remaining inaccuracy of 2D-COR, COR was applied to 1.5T 3D MR imaging.

MATERIALS AND METHODS

Twelve experimental rabbit aneurysms were subjected to stent-assisted coil embolization followed by 2D DSA and 3D MR imaging. Subjective occlusion-rate (SOR) was estimated. Linear parameters (aneurysm length, neck width, parent vessel diameter) were measured on 2D DSA and 3D MR imaging. The occlusion rate was measured by contrast medium-based identification of the nonoccluded 2D area/3D volume in relation to the total aneurysm 2D area/3D volume. 2D and 3D parameters were statistically compared.

RESULTS

There were no limiting metallic artifacts by using 3D MR imaging. Linear parameters (millimeters) were nearly identical on 2D DSA and 3D MR imaging (aneurysm length: 7.5 ± 2.6 versus 7.4 ± 2.5, P = .2334; neck width: 3.8 ± 1.0 versus 3.7 ± 1.1, P = .6377; parent vessel diameter: 2.7 ± 0.6 versus 2.7 ± 0.5, P = .8438), proving the high accuracy of 3D MR imaging. COR measured on 3D MR imaging was considerably lower (61.8% ± 26.6%) compared with the following: 1) 2D-COR (65.6% ± 27.1%, P = .0537) and 2) 2D-SOR estimations (69.2% ± 27.4%, P = .002). These findings demonstrate unacceptable bias in the current clinical standard SOR estimations.

CONCLUSIONS

3D-COR of embolized aneurysms is easily feasible. Its accuracy is superior to that of the clinical standard 2D-SOR. The difference between 3D-COR and 2D-COR approached statistical significance. 3D-COR may add objectivity to the ability to stratify the risk of rerupture in embolized cerebral aneurysms.

Microsurgical venous pouch arterial-bifurcation aneurysms in the rabbit model: technical aspects

For ruptured human cerebral aneurysms endovascular embolization has become an equivalent alternative to aneurysm clipping.(1) However, large clinical trials have shown disappointing long-term results with unacceptable high rates of aneurysm recanalization and delayed aneurysm rupture.(2) To overcome these problems, animal experimental studies are crucial for the development of better endovascular devices.(3-5) Several animal models in rats, rabbits, canines and swine are available.(6-8) Comparisons of the different animal models showed the superiority of the rabbit model with regard to hemodynamics and comparability of the coagulation system and cost-effectiveness.(9-11) The venous pouch arterial bifurcation model in rabbits is formed by a venous pouch sutured into an artificially created true bifurcation of both common carotid arteries (CCA). The main advantage of this model are true bifurcational hemodynamics.(12) The major drawbacks are the sofar high microsurgical technical demands and high morbidity and mortality rates of up to 50%.(13) These limitations have resulted in less frequent use of this aneurysm model in the recent years. These shortcomings could be overcome with improved surgical procedures and modified peri- and postoperative analgetic management and anticoagulation.(14-16) Our techniques reported in this paper demonstrate this optimized technique for microsurgical creation of arterial bifurcation aneurysms.

Complex bilobular, bisaccular, and broad-neck microsurgical aneurysm formation in the rabbit bifurcation model for the study of upcoming endovascular techniques

BACKGROUND AND PURPOSE

Despite rapid advances in the development of materials and techniques for endovascular intracranial aneurysm treatment, occlusion of large broad-neck aneurysms remains a challenge. Animal models featuring complex aneurysm architecture are needed to test endovascular innovations and train interventionalists.

MATERIALS AND METHODS

Eleven adult female New Zealand rabbits were assigned to 3 experimental groups. Complex bilobular, bisaccular, and broad-neck venous pouch aneurysms were surgically formed at an artificially created bifurcation of both CCAs. Three and 5 weeks postoperatively, the rabbits underwent 2D-DSA and CE-3D-MRA, respectively.

RESULTS

Mortality was 0%. We observed no neurologic, respiratory, or gastrointestinal complications. The aneurysm patency rate was 91% (1 aneurysm thrombosis). There was 1 postoperative aneurysm hemorrhage (9% morbidity). The mean aneurysm volumes were 176.9 ± 63.6 mm(3), 298.6 ± 75.2 mm(3), and 183.4 ± 72.4 mm(3) in bilobular, bisaccular, and broad-neck aneurysms, respectively. The mean operation time was 245 minutes (range, 175-290 minutes). An average of 27 ± 4 interrupted sutures (range, 21-32) were needed to create the aneurysms.

CONCLUSIONS

This study demonstrates the feasibility of creating complex venous pouch bifurcation aneurysms in the rabbit with low morbidity, mortality, and high short-term aneurysm patency. The necks, domes, and volumes of the bilobular, bisaccular, and broad-neck aneurysms created are larger than those previously described. These new complex aneurysm formations are a promising tool for in vivo animal testing of new endovascular devices.

Berengario da Carpi: a pioneer in neurotraumatology

Berengario da Carpi was one of the most famous physicians of the 16th century, a recognized master of anatomy and surgery, an emblematic "Renaissance man" who combined his medical experience and engineering knowledge to design new surgical instruments, and effectively used the arts of writing and drawing to describe state-of-the-art medicine and provide illustrations of anatomical structures. His greatest contribution to medicine was to write the most important work on craniocerebral surgery of the 16th century, the Tractatus de Fractura Calvae sive Cranei (Treatise on Fractures of the Calvaria or Cranium), in which he described an entire set of surgical instruments to be used for cranial operations to treat head traumas that became a reference for later generations of physicians. This was a systematic treatise covering the mechanisms, classification, and medical and surgical treatment of head traumas, and can be considered a milestone in the history of neurotraumatology.

Improved microsurgical creation of venous pouch arterial bifurcation aneurysms in rabbits

BACKGROUND AND PURPOSE

The choice of the experimental aneurysm model is essential for valid embolization-device evaluations. So far, the use of the rabbit venous pouch arterial bifurcation aneurysm model has been limited by demanding microsurgery, low aneurysm patency rates, and high mortality. This study aimed to facilitate microsurgery and to reduce mortality by optimized peri-/postoperative management.

MATERIALS AND METHODS

Aneurysms were created in 16 New Zealand white rabbits under general intravenous anesthesia. Using modified microsurgical techniques, we sutured a jugular vein pouch into a bifurcation created between both CCAs. Aggressive anticoagulation (intraoperative intravenous: 1000-IU heparin, 10-mg acetylsalicylic acid/kg; postoperative subcutaneous: 14 days, 250-IU/kg /day heparin) and prolonged postoperative anesthesia (fentanyl patches: 12.5 μg/h for 72 hours) were applied. Angiographic characteristics of created experimental aneurysms were assessed.

RESULTS

The reduced number of interrupted sutures and aggressive anticoagulation caused no intra-/postoperative bleeding, resulting in 0% mortality. Four weeks postoperation, angiography showed patency in 14 of 16 aneurysms (87.5%) and Ohshima type B bifurcation geometry. Mean values of parent-artery diameters (2.3 mm), aneurysm lengths (7.9 mm), and neck widths (4.1 mm) resulted in a mean 1.9 aspect ratio.

CONCLUSIONS

Compared with historical controls, the use of modified microsurgical techniques, aggressive anticoagulation, and anesthesia resulted in higher aneurysm patency rates and lower mortality rates in the venous pouch arterial bifurcation aneurysm model. Gross morphologic features of these aneurysms were similar to those of most human intracranial aneurysms.

Ruptured carotid artery aneurysms of the ophthalmic (C6) segment: clinical and angiographic long term follow-up of a multidisciplinary management strategy

BACKGROUND

The management of ruptured C6 aneurysms remains controversial. Detailed long-term outcome data are still lacking. Thus the present study provided a detailed long term follow-up for a multidisciplinary approach combining microsurgical clipping, endovascular embolisation and parent artery occlusion with/without bypass protection.

METHODS

In our single centre analysis of 64 consecutive patients, indications for microsurgery were: superior aneurysm projection, giant/large or wide necked aneurysms and aneurysms at branching sites. Indications for embolisation were: narrow necks, neck calcification, close aneurysm relation to the clinoid process or adhesion to the distal dural ring, and aneurysm location in the concavity of the carotid siphon curve.

RESULTS

23 patients (35.9%) underwent microsurgery, 38 patients (59.4%) embolisation and three patients (4.7%) parent artery occlusion under bypass protection. Retreatment was required in 20.9% (surgery 8.7%, endovascular 31.6%). Procedure related transient complications occurred in 10.9% (surgery 13.0%, endovascular 10.5%). Procedure related permanent morbidities occurred in 6.3% (surgery 8.7%, endovascular 5.3%), including visual deficits in 4.7% (surgery 4.4%, endovascular 5.3%). One endovascular patient died. Angiographic follow-up (29.2 (SD 31.9) months) revealed total aneurysm occlusion in 94.4% of the surgical and 82.9% of the endovascular patients. Clinical follow-up (58.7 (SD 47.6) months) showed 73.4% of the population reaching Glasgow Outcome Scale 4-5, these data being equivalent to the International Subarachnoid Aneurysm Trial (ISAT) outcomes.

CONCLUSIONS

Based on favourable neuroradiological and ophthalmological outcomes, microsurgery is recommended for superiorly projecting aneurysms, especially aneurysms involving the ophthalmic artery, and for giant/large or wide necked aneurysms. Based on stable aneurysm occlusion and excellent clinical outcomes, embolisation can be recommended for inferiorly/medially projecting small, narrow necked aneurysms.

Computerized assessment of angiographic occlusion rate and coil density in embolized human cerebral aneurysms

BACKGROUND AND PURPOSE

Computerized methods have been introduced for more objective quantification of angiographic occlusion rate and coil density as parameters of successful embolization. This study aimed 1) to evaluate this new computerized method for angiographic occlusion rating and coil density calculations by comparison with corresponding histometric parameters from retrieved human aneurysms, and 2) to compare the new computerized method with the present standard of subjective angiographic occlusion rating.

MATERIALS AND METHODS

From 14 postmortem-retrieved human aneurysms, angiographic occlusion rate was determined by contrast medium attenuation-gradient distinction on digital subtraction angiographs after Guglielmi detachable coil (GDC) embolization. Angiographic coil density was calculated, approximating aneurysms as ellipsoid and coils as cylindric volumes. On surface-stained histologic ground sections of the respective aneurysms, the occluded aneurysm area and coil area were measured. Then, we calculated and compared the histometric occlusion rates and coil densities with the corresponding angiographic parameters by using the Wilcoxon paired signed-rank test and the Spearman rank correlation.

RESULTS

Computerized angiographic occlusion rates (75%-100%) showed good correlation (r = 0.799; P < .01) with histometric occlusion-rates (61%-100%), resulting in no statistically significant differences (P = .2163). With 5.1% (+/-3.8), the mean difference between computerized angiographic occlusion rates and histometry was substantially lower compared with 10.7% (+/-8.7) mean difference between subjective angiographic estimations and histometry. Calculated angiographic coil density (13%-32%) significantly differed from histometric coil density (8%-35%; P < .05).

CONCLUSIONS

For recanalized aneurysms, computerized angiographic occlusion rating showed better correspondence with histometry compared with subjective angiographic occlusion rating. Clinical application of this new tool may lead to more objective cutoff values for re-embolization indications. The value of coil density calculations seems limited by the approximation of the aneurysms as ellipsoid volumes.

Long-term outcome of a multidisciplinary concept of spinal dural arteriovenous fistulae treatment

INTRODUCTION

The optimal treatment of spinal dural arteriovenous fistulae (SDAVF) remains controversial and long-term follow-up data, especially data from multidisciplinary treatment, are rarely available. Thus, long-term outcomes following a multidisciplinary approach to the treatment of SDAVF were investigated.

METHODS

The investigation included 26 patients with SDAVF treated at the authors' department over a 15-year period including a follow-up of more than 2 years. The treatment strategy when occlusion of the draining vein could be achieved was to embolize the fistula with Histoacryl, with surgery reserved for those patients unsuitable for embolization. Posttreatment angiography followed by MRI was performed in all patients. Clinical follow-up was performed using the gait and micturition Aminoff-Logue scale scores and the modified Rankin scale score.

RESULTS

Embolization was performed in 19 patients (73.1%), and direct surgery in 7 patients (26.9%). Follow-up angiography (at a mean of 21.7 months) showed occlusion of the SDAVF in 24 patients (92.3%). Of the 19 embolized patients, 2 (10.5%) developed recurrence secondary to insufficient occlusion of the SDAVF draining vein, and one of these two patients underwent re-embolization and one re-operation. No negative effects of SDAVF recurrence on the final clinical outcome were identified in either patient. MRI after angiography (at a mean of 91.5 months) demonstrated occlusion of all SDAVFs. After a mean clinical follow-up of 103.4 months there was a statistically significant improvement in both the modified Rankin scale score and the Aminoff-Logue gait scale score (P < 0.05).

CONCLUSION

The present multidisciplinary study showed for the first time that embolization leads to stable neuroradiological results and favourable clinical outcomes even for very long follow-up times of more than 100 months. Microsurgery remains the treatment of choice when safe embolization of the draining vein cannot be achieved.

Computer-assisted quantification of occlusion and coil densities on angiographic and histological images of experimental aneurysms

OBJECTIVE

Occlusion rates (OR) and coil densities were quantified by computer-assisted morphometry on angiograms and histological ground sections of coil-embolized experimental aneurysms. The aims of this study were 1) to develop computer-assisted evaluations of angiographic OR and histometrical OR, 2) to compare these results to subjectively estimated angiographic OR from clinical practice, and 3) to test the correlation between histometrical data of coil density and occlusion.

METHODS

Eight rabbit carotid-bifurcation aneurysms had been followed by digital subtraction angiography (DSA) before and after Guglielmi detachable coil embolization and at sacrifice (1 h to 24 wk postembolization). Angiographic OR was subjectively estimated, then determined by computer-assisted density-gradient distinction on digitized DSAs. Histometrically, maximum length, neck width, total area, recanalized area, and coil-occupied area were measured on digitized and calibrated color micrographs from surface-stained histological ground sections of the aneurysms. Histometrical OR and coil density were calculated as indirect parameters.

RESULTS

Subjective versus computer-assisted angiographic OR yielded for one aneurysm, 100% versus 100%, and for three aneurysms less than 90% versus 65 to 60% occlusion. For four aneurysms, OR was estimated greater than 90%, whereas computer-assisted OR ranged between 45 to 80%, the latter being more precise because of better definition of the aneurysm's total area on digitized DSA. Histometrical OR ranged between 32.8 and 87.6%, but did not correlate significantly with computer-assisted angiographic OR (r = 0.467, P > 0.1) because of differences in two aneurysms. Coil densities between 5.5 and 22.1% were slightly lower than reported in literature but significantly correlated to histometrical OR (r = 0.646, P < 0.05).

CONCLUSION

Computer-assisted DSA evaluation, delivering more precise values than subjectively estimated occlusion, may be a useful tool for follow-up studies. Comparing computer-assisted angiographic with histometrical occlusion demonstrates limits of DSA in displaying the real morphology of coil-embolized aneurysms. The clinically postulated correlation of OR and coil densities was statistically corroborated.

Comparison of mouth-to-mouth resuscitation and Combitube ventilation in a bench model

CONTEXT

In addition to heart massage, the primary goal of cardiopulmonary resuscitation is efficient oxygenation and ventilation.

OBJECTIVE

To compare the ease of learning and handling of standard mouth-to-mouth resuscitation with the Combitube (Tyco Healthcare Nellcor, Pleasanton, CA) ventilation.

METHODS

After a 30 minute theoretical introduction and demonstration of mouth-to-mouth resuscitation and use of the Combitube in mannequins, following American Heart Association guidelines, 26 adolescent school children (15 of them 14 years old, 11 of them 10 years old) undertook two ventilation trials, each consisting of five single ventilations, with each technique. Only the second trial with each technique was evaluated. Qualitative implementation (grades: very good, good, failed) was evaluated, several procedure-related time points were recorded, and tidal volumes (ml) were measured.

RESULTS

With mouth-to-mouth resuscitation, the time interval until start of first ventilation was 36.5 seconds shorter than with the Combitube (P < 0.001). With the Combitube, the time needed for five single ventilations was 6.4 seconds less than with mouth-to-mouth resuscitation (P < 0.001) and mean tidal volumes were higher (mouth-to-mouth resuscitation, 450 +/- 384 ml, versus Combitube, 735 +/- 358 ml; P < 0.05).

CONCLUSION

Most of the school children performed both techniques to a high qualitative level. The study shows that mouth-to-mouth resuscitation and use of the Combitube have equal ease of learning, a precondition for proficient retention of skills. Tidal volumes were significantly higher with the Combitube and, not surprisingly, the time interval until the start of first ventilation was significantly shorter with mouth-to-mouth resuscitation. Regardless of the ventilation technique or device, we believe that subsequent retraining of ventilation skills is very important.

Gender Differences in Outcome of Conservatively Treated Patients With Asymptomatic High Grade Carotid Stenosis

Background and Purpose— Gender differences are currently becoming increasingly recognized as an important prognostic factor in patients with atherosclerotic disease. We investigated gender-related differences in vascular outcome and mortality of asymptomatic patients with high-grade internal carotid artery (ICA) stenosis.

Methods— We enrolled 525 consecutive patients (325 males with a median age of 72 years and 200 females with a median age of 75 years) from a single center registry who were initially treated conservatively with respect to a neurologically asymptomatic ≥70% ICA stenosis. Patients were followed-up for a median of 38 months (interquartile range, 18 to 65) for major adverse cardiovascular, cerebral, and peripheral vascular events (MACE: combined end point including myocardial infarction, stroke, [partial] limb amputation, and death), vascular mortality, and all-cause mortality.

Results— Cumulative MACE-free survival rates in males and females at 1, 3, and 5 years were 83%, 65%, 48% versus 85%, 73%, and 67% ( P =0.004), respectively. Adjusted hazard ratios for MACE, vascular mortality, and all-cause mortality for males were 1.96 ( P =0.016), 2.48 ( P <0.001), and 1.70 ( P =0.007) as compared with females, irrespective of age, vascular risk factors, comorbidities, and the individual risk status estimated by the American Society of Anesthesiologists (ASA) score.

Conclusion— Male patients with high-grade carotid artery stenosis are at a considerably higher risk for poor outcome than their female counterparts. In particular, the risk for fatal vascular events is substantially increased in males.

Neurological Outcome of Conservative Versus Endovascular Treatment of Patients With Asymptomatic High-Grade Carotid Artery Stenosis:A Propensity Score–Adjusted Analysis

PURPOSE

To report a propensity score-adjusted analysis of the long-term risks for stroke after carotid artery stenting (CAS) compared to medical therapy in patients with asymptomatic high-grade carotid artery stenosis.

METHODS

A total of 946 consecutive patients (605 men; median age 73 years) with asymptomatic high-grade carotid artery stenoses (> or =70%) identified in a single center registry were treated either medically (n=525) or with CAS (n=421). A propensity score-adjusted analysis was performed to test the hypothesis that long-term neurological outcome might be better after CAS than after medical treatment, depending on the baseline degree of carotid stenosis and the patient's medical status. Baseline degree of stenosis was classified as 70% to 79% (n=307), 80% to 89% (n=366), and 90% to 99% (n=272) by duplex ultrasound. Surgical risk was estimated by the American Society of Anesthesiologists (ASA) score (I to IV).

RESULTS

Stroke-free survival rates at 1, 3, and 5 years were 97%, 93%, and 89% after conservative treatment versus 94%, 93%, and 91% after CAS (p=0.56), respectively. Compared to conservatively treated patients with 70% to 79% stenoses, the adjusted hazard ratios for stroke were 2.36 (p=0.044) for conservatively treated patients with 80% to 89% and 3.17 (p=0.026) for those with 90% to 99% stenoses. For CAS patients with 70% to 79%, 80% to 89%, and 90% to 99% stenoses, the adjusted hazard ratios for stroke were 1.32 (p=0.63), 0.91 (p=0.84), and 0.98 (p=0.98) irrespective of the ASA score, the propensity to undergo CAS, and other potential confounders. Thus, the risk of stroke increased in parallel with the degree of stenosis in conservatively treated patients, but remained unchanged in patients undergoing CAS.

CONCLUSIONS

Patients with asymptomatic severe carotid narrowing (> or =80%) might benefit from CAS with respect to stroke-free survival. Randomized controlled trials are needed to confirm these findings.

Effectiveness of mouth-to-mouth resuscitation performed by young adolescents on a mannequin

Bystanders are reluctant to perform basic life support (BLS) because of fear of failure and of infection, especially with mouth-to-mouth resuscitation (MTM). A possibility to enhance willingness could be the giving of MTM or BLS instructions at a very early age to the potential rescuers. The study aimed to investigate the effectiveness of MTM with respect to ventilation and the time needed for performing 5 ventilations. In this study, MTM was performed on a mannequin by 57 children and adolescents aged 10 and 14 years. This study showed that 14-year-olds effectively perform MTM, reaching the recommended tidal volumes. Ten-year-old children have already developed sufficient motor skills for MTM with no significant time differences compared with the 14-year-olds. However, physical demands may be rather high at this age. Further long-term studies are needed to investigate clinical benefits of early teaching of MTM or BLS that may lead to international guidelines with low age limits.

Closed suctioning system reduces cross-contamination between bronchial system and gastric juices

In this prospective, randomized study, we evaluated whether a closed suctioning (CS) system (TrachCare) influences crossover contamination between bronchial system and gastric juices when compared with an open suctioning system (OS). The secondary aims were an analysis of the frequency of ventilator-associated pneumonia (VAP) and an analysis of alteration in gas exchange. Antibiograms were performed from tracheal secretions and gastric juice aspirates on Days 1 and 3 of intubation in 24 patients in a medical intensive care unit. Five cross-contaminations were observed in the OS group on Day 3 versus Day 1; the 5 strains shared common genotypes as determined by random amplification of polymorphic DNA. No cross-contaminations were seen in the CS group (P = 0.037). VAP occurred in 5 patients of the OS group but in none of the CS group patients (P = 0.037). Spao(2) decreased significantly in the OS group compared with presuctioning values--the opposite of the CS group. Whereas presuctioning values were comparable between groups, postsuctioning Spao(2) was significantly higher in the CS group. CS significantly reduced cross-contamination between bronchial system and gastric juices and reduced the incidence of VAP when compared with OS. Hypoxic phases can be reduced by the help of CS.

Inhibition of Platelet Function by Hydroxyethyl Starch Solutions in Chronic Pain Patients Undergoing Peridural Anesthesia

The use of hydroxyethyl starch (HES) solutions as a fluid replacement before peridural blockade may compromise blood coagulation, thus increasing the risk of neuraxial bleeding. In this prospective, double-blind, placebo-controlled, crossover study, we compared the influence of HES 130 (molecular weight in kilodalton), HES 200, and lactated Ringer's solution on platelet function and hemodynamics in chronic low back pain patients scheduled for peridural blockades. Patients received 3 test infusions of 10 mL/kg each administered IV for 30 min. Collagen/epinephrine and collagen/adenosine diphosphate were used as agonists for assessment of platelet function analyzer-closure times. Arterial blood pressure, heart rate, platelet counts, and hemoglobin levels were documented. Platelet function analyzer-closure times remained stable after lactated Ringer's solution but were significantly prolonged after HES. The platelet-inhibiting effect of HES 200 was more than that of HES 130. Hemodynamic stability was sufficiently maintained by all test infusions. In contrast to previous observations, a relevant antiplatelet effect of both low and medium molecular weight HES solutions was found in this study in chronic pain patients undergoing peridural anesthesia. Because hemostasiological competence is a prerequisite for safe neuraxial blockade, the decision of HES for intravascular fluid administration before blockade should be critically made.

Primary Patency of Femoropopliteal Arteries Treated with Nitinol versus Stainless Steel Self-expanding Stents: Propensity Score–adjusted Analysis

PURPOSE

To evaluate, in a propensity score-adjusted analysis, the intermediate-term primary patency rates associated with nitinol versus stainless steel self-expanding stent placement for treatment of atherosclerotic lesions in femoropopliteal arteries.

MATERIALS AND METHODS

The authors analyzed the clinical and imaging data of 175 consecutive patients with peripheral artery disease and either intermittent claudication (n = 150) or critical limb ischemia (n = 25) who underwent femoropopliteal artery implantation of nitinol (n = 104) or stainless steel (n = 123) stents in a nonrandomized setting. The stents were placed owing to either significant residual stenosis (ie, >30% lumen diameter reduction) or flow-limiting dissection after initial balloon angioplasty of the femoropopliteal artery. Patients were followed up for a median period of 9 months (mean, 13 months; range, 6-66 months) for the detection of a first in-stent restenosis, defined as a greater than 50% lumen diameter reduction that was seen at color-coded duplex ultrasonography and confirmed at angiography.

RESULTS

Cumulative patency rates at 6, 12, and 24 months were 85%, 75%, and 69%, respectively, after nitinol stent placement versus 78%, 54%, and 34%, respectively, after stainless steel stent placement (P =.008, log-rank test). There were no statistically significant differences in associated patency among the three different nitinol stents used (P =.72, log-rank test). Multivariate Cox proportional hazard analysis, in which the effect of propensity to receive a nitinol stent was considered, revealed a significantly reduced risk of restenosis with the nitinol stents compared with the risk of restenosis with the stainless steel stents (adjusted hazard ratio, 0.44; 95% confidence interval: 0.22, 0.85; P =.014).

CONCLUSION

Nitinol stents are associated with significantly improved primary patency rates in femoropopliteal arteries compared with stainless steel stents. Randomized controlled trials are needed to confirm these results.