The Utility of Superselective Rotational Angiography for Frameless Stereotactic Navigation During Craniotomy for Micro-Arteriovenous Malformation

BACKGROUND

Micro-arteriovenous malformations (AVMs) can present challenges to neurosurgeons with respect to localization during resection. We sought to describe a novel method that merges super-selective 3-dimensional angiographic images with magnetic resonance imaging (MRI) sequences to facilitate frameless stereotaxic navigation during AVM surgery.

METHODS

A retrospective analysis was performed comprising cases that employed merging of angiographic and MRI images for navigation purposes. Baseline clinical and imaging features were recorded. The technique and operative experiences were analyzed descriptively and presented alongside detailed illustrative cases.

RESULTS

During the review period, 11 cases were identified where this technique was employed. Successful image acquisition and merging was possible in all cases. Complete obliteration of the target pathology was achieved in all cases. Precise localization of the micro-AVMs minimized dissection in eloquent cortex.

CONCLUSIONS

Superselective 3-dimensional angiographic images merged to baseline MRI sequences facilitates planning and navigation during surgery for micro-AVMs.

The value of intraoperative angiography in the time of indocyanine green videoangiography in the treatment of cerebrovascular lesions: Efficacy, workflow, risk-benefit and cost analysis A prospective study

INTRODUCTION

Intraoperative digital subtraction angiography (ioDSA) allows early treatment evaluation after neurovascular procedures. However, the value and efficiency of this procedure has been discussed controversially. We have evaluated the additional value of hybrid operating room equipped with an Artis Zeego robotic c-arm regarding cost, efficiency and workflow. Furthermore, we have performed a risk-benefit analysis and compared it with indocyanine green (ICG) angiography.

METHODS

For 3 consecutive years, we examined all neurovascular patients, treated in the hybrid operating theater in a risk-benefit analysis. After using microdoppler and ICG angiography for best operative result, every patient received an additional ioDSA to look for remnants or unfavorable clip placement which might lead to a change of operating strategy or results. Furthermore, a workflow-analysis reviewing operating steps, staff positioning, costs, technical errors or complications were conducted on randomly selected cases.

RESULTS

54 patients were enrolled in the risk-benefit analysis, 22 in the workflow analysis. The average duration of a cerebrovascular operation was 4 h 58 min 2 min 35 s accounted for ICG angiography, 46 min 4 s for ioDSA. Adverse events occurred during one ioDSA. In risk-benefit analysis, ioDSA was able to detect a perfusion rest in 2 out of 43 cases (4,7%) of aneurysm surgery, which could not have been visualized by ICG angiography before. In arterio-venous-malformation (AVM) surgery, one of 11 examined patients (7,7%) showed a remnant in ioDSA and resulted in additional resection. The average cost of an ioDSA in Ulm University can be estimated with 1928,00€.

CONCLUSION

According to our results ioDSA associated complications are low. Relevant findings in ioDSA can potentially avoid additional intervention, however, due to the high costs and lower availability, the main advantage might lie in the treatment of selected patients with complexes neurovascular pathologies since ICG angiography is equally safe but associated with lower costs and better availability.

Amended Intraoperative Neuronavigation: Three-Dimensional Vascular Roadmapping with Selective Rotational Digital Subtraction Angiography

BACKGROUND

Accuracy of intraoperative cerebrovascular neuronavigation is difficult to maintain because of the ongoing need for brain shift correction. By including 3-dimensional rotational intraoperative digital subtraction angiography (3D-iDSA), the intraoperative cerebrovascular neuronavigation can be updated and upgraded throughout the microneurosurgical procedure. The aim of this technical note is to demonstrate the feasibility and advantage of updating and upgrading the accuracy of targeted cerebrovascular neuronavigation with an intraoperative 3D-DSA dataset.

METHODS

A preoperative diagnostic selective 3D-DSA was registered with the neuronavigation software, followed by the automated segmentation of the vascular object of interest (an aneurysm in this case). After acquiring additional 3D-iDSA volumes, these steps were repeated, thereby updating the cerebrovascular roadmap and neuronavigation accuracy (i.e., brain shift correction).

RESULTS

This technique was applied successfully in a patient who underwent elective microneurosurgical clipping of a right-sided middle cerebral artery (MCA) bifurcation aneurysm in a hybrid neurosurgical operating setting. After clipping of the MCA aneurysm, a selective 3D iDSA was performed that was then used to update the projection and accuracy of the initial 3D neurovascular object of interest (i.e., the aneurysm). In this revised rotational view, the projection refined the target segments of the clipped MCA aneurysm, the accuracy of clipping, and brain shift correction.

CONCLUSIONS

3D-iDSA vascular segmentations can update und upgrade the intraoperative neurovascular roadmap by thereby enhancing accuracy of cerebrovascular neuronavigation, as well as correcting brain shift. This technique is feasible within the hybrid operation room. Evaluation in larger series is required to support these findings.

Frameless Stereotactic Navigation during Insular Glioma Resection using Fusion of Three-Dimensional Rotational Angiography and Magnetic Resonance Imaging

BACKGROUND

Perioperative cerebral infarction is a potential complication of glioma resection, of which insular tumors are at higher risk because of the proximity of middle cerebral artery branches, including the lateral lenticulostriates and long insular arteries. In this study, 3 patients received three-dimensional rotational angiography, which was fused with magnetic resonance imaging (MRI) for frameless stereotactic navigation during dominant-hemisphere insular glioma resection.

METHODS

All patients obtained a preoperative catheter angiogram with a three-dimensional rotational acquisition of the ipsilateral internal carotid artery. The pixel-based axial three-dimensional angiography data, thin-cut structural MRI, tractography from diffusion tensor imaging, and expressive language activation from functional MRI were uploaded into the iPlan software (Brainlab, Heimstetten, Germany) and fused. The target tumor, regional blood vessels, adjacent functional areas, and their associated fiber tracts were segmented and overlaid on the appropriate MRI sequence. This image fusion was used preoperatively to visualize the relationship of the mass with the adjacent vasculature and intraoperatively for frameless stereotactic navigation to optimize preservation of arterial structures.

RESULTS

Three patients aged 27-60 years with excellent baseline functional status presented with seizures and were found to have a large dominant-hemisphere T2 hyperintense nonenhancing insular mass. Surgical resection was performed using multimodality neuronavigation. None sustained a postoperative arterial infarction or a perioperative neurologic deficit.

CONCLUSIONS

Neuronavigation using a fusion of three-dimensional rotational angiography with MRI is a technique that can be used for preoperative planning and during resection of insular gliomas to optimize preservation of adjacent arteries.

Frameless neuronavigation based only on 3D digital subtraction angiography using surface-based facial registration

OBJECT

Cerebrovascular lesions can have complicated abnormal anatomy that is not completely characterized by CT or MR angiography. Although 3D rotational angiography provides superior spatial and temporal resolution, catheter angiograms are not easily registered to the patient, limiting the use of these images as a source for neuronavigation. However, 3D digital subtraction angiography (DSA) contains not only vascular anatomy but also facial surface anatomy data. The authors report a novel technique to register 3D DSA images by using only the surface anatomy contained within the data set without having to fuse the DSA image set to other imaging modalities or use fiducial markers.

METHODS

A cadaver model was first created to assess the accuracy of neuronavigation based on 3D DSA images registered by facial surface anatomy. A 3D DSA scan was obtained of a formalin-fixed cadaver head, with acquisitions of mask and contrast runs. The right common carotid artery was injected prior to the contrast run with a 45% contrast solution diluted with water-soluble red liquid latex. One week later, the head was registered to a neuronavigation system loaded with the 3D DSA images acquired earlier using facial surface anatomy. A right pterional craniotomy was performed and 10 different vascular landmarks were identified and measured for accuracy using the neuronavigation system. Neuronavigation based only on 3D DSA was then used to guide an open clipping procedure for a patient who presented with a ruptured distal lenticulostriate aneurysm.

RESULTS

The accuracy of the measurements for the cadaver model was 0.71 ± 0.25 mm (mean ± SE), which is superior to the 1.8-5 mm reported for neuronavigation. The 3D DSA-based navigation-assisted surgery for the distal lenticulostriate aneurysm aided in localization, resulting in a small craniotomy and minimal brain dissection.

CONCLUSIONS

This is the first example of frameless neuronavigation based on 3D catheter angiography registered by only the surface anatomy data contained within the 3D DSA image set. This is an easily applied technique that is beneficial for accurately locating vascular pathological entities and reducing the dissection burden of vascular lesions.

A mathematical model of utility for single screening of asymptomatic unruptured intracranial aneurysms at the age of 50 years

BACKGROUND

Although rupture of intracranial aneurysms carries high mortality and morbidity rates, the clinical and financial benefit of screening certain high-risk groups is uncertain. We designed a mathematical model to interrogate the clinical benefit and cost-effectiveness of screening.

METHODS

A decision tree analysis model was used to calculate the outcome and cost of two scenarios applied to the same population: one-off screening for intracranial aneurysms versus not screening. Each scenario had an associated gain or loss of Quality Adjusted Life Years (QALY) and cost; the difference between the two scenarios was calculated. The variable inputs were the aneurysm prevalence and risk of rupture after 5 years. Sensitivity analyses were performed to determine the effects of altering various factors on outcomes.

RESULTS

Screening of the asymptomatic general population results in a QALY loss, equating to a negative clinical impact. The threshold 5-year risk of rupture at which screening resulted in a gain in QALYs was 13 %. This held true for any prevalence between 1 and 25 %. Risk of rupture had a greater impact on outcome than prevalence. Halving the risk of intervention (either surgery or coiling) reduced the threshold 5-year risk of rupture at which screening results in gain of QALYs to 6 %. The age of screening also had important effects on outcome.

CONCLUSIONS

The QALY benefit and cost-effectiveness of screening are most sensitive to the 5-year risk of rupture. Screening is beneficial only in populations with a high risk of rupture; this should be the focus of future research.