Category: Vascular

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Augmented reality in the surgery of cerebral arteriovenous malformations

Augmented reality in the surgery of cerebral arteriovenous malformations

Acta Neurochir (2014) 156:1769–1774

Augmented reality technology has been used for intraoperative image guidance through the overlay of virtual images, from preoperative imaging studies, onto the realworld surgical field. Although setups based on augmented reality have been used for various neurosurgical pathologies, very few cases have been reported for the surgery of arteriovenous malformations (AVM). We present our experience with AVM surgery using a system designed for image injection of virtual images into the operating microscope’s eyepiece, and discuss why augmented reality may be less appealing in this form of surgery.

Methods N=5 patients underwent AVM resection assisted by augmented reality. Virtual three-dimensional models of patients’ heads, skulls, AVM nidi, and feeder and drainage vessels were selectively segmented and injected into the microscope’s eyepiece for intraoperative image guidance, and their usefulness was assessed in each case.

Results Although the setup helped in performing tailored craniotomies, in guiding dissection and in localizing drainage veins, it did not provide the surgeon with useful information concerning feeder arteries, due to the complexity of AVM angioarchitecture.

Conclusion The difficulty in intraoperatively conveying useful information on feeder vessels may make augmented reality a less engaging tool in this form of surgery, and might explain its underrepresentation in the literature. Integrating an AVM’s hemodynamic characteristics into the augmented rendering could make it more suited to AVM surgery.

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Microsurgery for cerebral arteriovenous malformations: postoperative outcomes and predictors of complications in 264 cases

AVM PF

Neurosurg Focus 37 (3):E10, 2014

The authors conducted a study to assess the safety and efficacy of microsurgical resection of arteriovenous malformations (AVMs) and determine predictors of complications.

Methods. A total of 264 patients with cerebral AVMs were treated with microsurgical resection between 1994 and 2010 at the Jefferson Hospital for Neuroscience. A review of patient data was performed, including initial hemorrhage, clinical presentation, Spetzler-Martin (SM) grade, treatment modalities, clinical outcomes, and obliteration rates. Univariate and multivariate analyses were used to determine predictors of operative complications.

Results. Of the 264 patients treated with microsurgery, 120 (45%) patients initially presented with hemorrhage. There were 27 SM Grade I lesions (10.2%), 101 Grade II lesions (38.3%), 96 Grade III lesions (36.4%), 31 Grade IV lesions (11.7%), and 9 Grade V lesions (3.4%). Among these patients, 102 (38.6%) had undergone prior endovascular embolization. In all patients, resection resulted in complete obliteration of the AVM. Complications occurred in 19 (7.2%) patients and resulted in permanent neurological deficits in 5 (1.9%). In multivariate analysis, predictors of complications were increasing AVM size (OR 3.2, 95% CI 1.5–6.6; p = 0.001), increasing number of embolizations (OR 1.6, 95% CI 1.1–2.2; p = 0.01), and unruptured AVMs (OR 2.7, 95% CI 1–7.2; p = 0.05).

Conclusions. Microsurgical resection of AVMs is highly efficient and can be undertaken with low rates of morbidity at high-volume neurovascular centers. Unruptured and larger AVMs were associated with higher complication rates.

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Lateral inferior cerebellar peduncle approach to dorsolateral medullary cavernous malformation

Dorsolateral medullary cavernous malformations

J Neurosurg 121:723–729, 2014

Brainstem cavernous malformations (BSCMs) present a unique therapeutic challenge to neurosurgeons. Resection of BSCMs is typically reserved for lesions that reach pial or ependymal surfaces. The current study investigates the lateral inferior cerebellar peduncle as a corridor to dorsolateral medullary BSCMs.

Methods. In this retrospective review, the authors present the cases of 4 patients (3 women and 1 man) who had a symptomatic dorsolateral cavernous malformation with radiographic and clinical evidence of hemorrhage.

Results. All patients underwent excision of the cavernous malformation via a far-lateral suboccipital craniotomy through the foramen of Luschka and with an incision in the inferior cerebellar peduncle. On intraoperative examination, 2 of the 4 patients had hemosiderin staining on the surface of the peduncle. All lesions were completely excised and all patients had a good or excellent outcome (modified Rankin Scale scores of 0 or 1).

Conclusions. This case series illustrates that intrinsic lesions of the dorsolateral medulla can be safely removed laterally through the foramen of Luschka and the inferior cerebellar peduncle.

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Twenty-Year Follow-up of Flow Reversal and Revascularization for a Giant Serpentine Basilar Artery Aneurysm

Twenty-Year Follow-up of Flow Reversal and Revascularization for a Giant Serpentine Basilar Artery Aneurysm

Operative Neurosurgery 10:E493–E497, 2014

Current microsurgical and endovascular therapies have offered little advancement for the treatment of complex vertebrobasilar aneurysms. The outcome of patients with these rare lesions has remained poor, despite sometimes heroic measures.

CLINICAL PRESENTATION: The authors report a case of a 65-year-old man who 20 years earlier had presented with symptoms suggestive of brainstem compression. Imaging at the time revealed a giant, serpentine aneurysm of the basilar artery. The patient was treated with superficial temporal artery to superior cerebellar artery bypass and decompression of the aneurysm contents. Twenty years after this treatment, the patient remains functionally intact with few sequelae from his treatment or the pathology. Follow-up imaging reveals thrombosis of the aneurysm without ischemic damage to the brainstem.

CONCLUSION: This case demonstrates that good functional outcomes are possible for select complex posterior circulation aneurysms by using flow reversal and revascularization; however, at this time, we are unable to predict for which patients this strategy will be successful.

KEY WORDS:

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Transdural indocyanine green video-angiography of vascular malformations

Transdural indocyanine green video-angiography of vascular malformations

Acta Neurochir (2014) 156:1761–1767

The role of indocyanine green videoangiography (ICG-VA) in the surgical resection of vascular malformations has been largely described; conversely, the utility of ICG-VA before dural opening (transdural ICG-VA) in this situation remains unclear. The aim of this study is to present the application of transdural ICG-VA in a consecutive series of patients in order to explore the potential provided by a transdural visualisation of vascular malformations.

Method We retrospectively analysed the application of intraoperative ICG-VA before dural opening in 15 consecutive patients who underwent surgical resection of vascular malformations. The cases included 12 cerebral arterio-venous malformations (AVMs), 2 cerebral dural arterio-venous fistulas (dAVFs) and 1 spinal arterio-venous fistula (AVF).

Results ICG-VA before dural opening allowed the visualisation of the site and extension of the malformation in 13 out of 15 cases, whilst arterial feeders and venous drainages were identified in 9 out of 15 cases. In two patients with dAVF, the point of fistula could be transdurally identified through ICGVA. In 14% of cases, the size of bone flap designed on neuronavigation data was then modified according to transdural ICG-VA findings.

Conclusions Transdural ICG-VA proved an efficient tool that allows optimising the exposure of the malformation, performing a safe dural opening and identifying dural vascular connections of the lesion.

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Increasing Flow Diversion for Cerebral Aneurysm Treatment Using a Single Flow Diverter

Increasing Flow Diversion for Cerebral Aneurysm Treatment Using a Single Flow Diverter

Neurosurgery 75:286–294, 2014

A neurovascular flow diverter (FD), aiming at inducing embolic occlusion of cerebral aneurysms through hemodynamic changes, can produce variable mesh densities owing to its flexible mesh structure.

OBJECTIVE: To explore whether the hemodynamic outcome would differ by increasing FD local compaction across the aneurysm orifice.

METHODS: We investigated deployment of a single FD using 2 clinical strategies: no compaction (the standard method) and maximum compaction across the aneurysm orifice (an emerging strategy). Using an advanced modeling technique, we simulated these strategies applied to a patient-specific wide-necked aneurysm model, resulting in a relatively uniform mesh with no compaction (C1) and maximum compaction (C2) at the aneurysm orifice. Pre- and posttreatment aneurysmal hemodynamics were analyzed using pulsatile computational fluid dynamics. Flow-stasis parameters and blood shear stress were calculated to assess the potential for aneurysm embolic occlusion.

RESULTS: Flow streamlines, isovelocity, and wall shear stress distributions demonstrated enhanced aneurysmal flow reduction with C2. The average intra-aneurysmal flow velocity was 29% of pretreatment with C2 compared with 67% with C1. Aneurysmal flow turnover time was 237% and 134% of pretreatment for C2 and C1, respectively. Vortex core lines and oscillatory shear index distributions indicated that C2 decreased the aneurysmal flow complexity more than C1. Ultrahigh blood shear stress was observed near FD struts in inflow region for both C1 and C2.

CONCLUSION: The emerging strategy of maximum FD compaction can double aneurysmal flow reduction, thereby accelerating aneurysm occlusion. Moreover, ultrahigh blood shear stress was observed through FD pores, which could potentially activate platelets as an additional aneurysmal thrombosis mechanism.

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Aneurysms of the anterior and posterior cerebral circulation: comparison of the morphometric features

Aneurysms of the anterior and posterior cerebral circulation- comparison of the morphometric features

Acta Neurochir (2014) 156:1647–1654

Intracranial aneurysms (IAs) located in the posterior circulation are considered to have higher annual bleed rates than those in the anterior circulation. The aim of the study was to compare the morphometric factors differentiating between IAs located in the anterior and posterior cerebral circulation.

Methods A total number of 254 IAs diagnosed between 2009 and 2012 were retrospectively analyzed. All patients qualified for diagnostic, three-dimensional rotational angiography. IAs were assigned to either the anterior or posterior cerebral circulation subsets for the analysis. Means were compared with a t-test. The univariate and stepwise logistic regression analyses were used to determine the predictors of morphometric differences between the groups. For the defined predictors, ROC (receiver-operating characteristic) curves and interactive dot diagrams were calculated with the cutoff values of the morphometric factors.

Results The number of anterior cerebral circulation IAs was 179 (70.5 %); 141 (55.5 %) aneurysms were ruptured. Significant differences between anterior and posterior circulation IAs were found for: the parent artery size (5.08±1.8 mm vs. 3.95±1.5mm; p<0.05), size ratio (2.22±0.9 vs. 3.19±1.8; p< 0.045) and aspect ratio (AR) (1.91±0.8 vs. 2.75±1.8; p= 0.02). Predicting factors differentiating anterior and posterior circulation IAs were: theAR (OR=2.20; 95%CI 1.80–270; Is 270 correct or should it be 2.70 and parent artery size (OR= 0.44; 95 % CI 0.38–0.54). The cutoff point in the ROC curve was 2.185 for the AR and 4.89 mm for parent artery size.

Conclusions Aspect ratio and parent artery size were found to be predictive morphometric factors in differentiating between anterior and posterior cerebral IAs.

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Are Aneurysms Treated With Balloon-Assisted Coiling and Stent-Assisted Coiling Different?

Are Aneurysms Treated With Balloon-Assisted Coiling and Stent-Assisted Coiling Different?

Neurosurgery 75:145–151, 2014

In the endovascular treatment of wide-necked unruptured aneurysms, there is controversy over which adjunctive device (stent vs balloon) is appropriate. At the payer level it has been posited that stents and balloons treat the same aneurysms, and, as such, the more expensive stents should not be reimbursed.

OBJECTIVE: We challenge this assertion, and instead hypothesize that aneurysms treated with stent assistance are morphologically different than those selected for balloon assistance.

METHODS: Retrospective review of unruptured aneurysms treated with an adjunctive device between 2008 and 2010. Morphological analysis was performed on the pretreatment 2-D catheter angiogram. The immediate posttreatment Raymond score was compared with that seen on the 12-month follow-up angiogram.

RESULTS: One hundred six unruptured aneurysms were treated with an adjunctive device and followed for a mean of 24.5 months. Morphological analysis revealed a lower dome-to-neck ratio (1.5 vs 1.2) and aspect ratio (1.44 vs 1.16) in the aneurysms treated with stent assistance vs balloon assistance. Of the 15.3% that were worse on follow-up angiography, there was no statistical difference between those treated with a stent vs a balloon (17.1% vs 14.2%). The overall re-treatment rate was 10.2% and was not statistically different between the 2 groups (12.7% vs 5.7%).

CONCLUSION: We found that unruptured aneurysms selected for treatment with stent-assisted coiling are morphologically different from those selected for treatment with balloon assistance. Despite the more challenging morphology, Raymond scores and re-treatment rates at 1 year were not statistically different between the 2 groups, suggesting an important role for stents in the treatment of unruptured aneurysms.

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High-Resolution Angioscopic Imaging During Endovascular Neurosurgery

High-Resolution Angioscopic Imaging During Endovascular Neurosurgery

Neurosurgery 75:171–180, 2014

Endoluminal optical imaging, or angioscopy, has not seen widespread application during neurointerventional procedures, largely as a result of the poor imaging resolution of existing angioscopes. Scanning fiber endoscopes (SFEs) are a novel endoscopic platform that allows high-resolution video imaging in an ultraminiature form factor that is compatible with currently used distal access endoluminal catheters.

OBJECTIVE: To test the feasibility and potential utility of high-resolution angioscopy with an SFE during common endovascular neurosurgical procedures.

METHODS: A 3.7-French SFE was used in a porcine model system to image endothelial disruption, ischemic stroke and mechanical thrombectomy, aneurysm coiling, and flowdiverting stent placement.

RESULTS: High-resolution, video-rate imaging was shown to be possible during all of the common procedures tested and provided information that was complementary to standard fluoroscopic imaging. SFE angioscopy was able to assess novel factors such as aneurysm base coverage fraction and side branch patency, which have previously not been possible to determine with conventional angiography.

CONCLUSION: Endovascular imaging with an SFE provides important information on factors that cannot be assessed fluoroscopically and is a novel platform on which future neurointerventional techniques may be based because it allows for periprocedural inspection of the integrity of the vascular system and the deployed devices. In addition, it may be of diagnostic use for inspecting the vascular wall and postprocedure device evaluation.

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Posterior Cerebral Artery Aneurysms: An Angiographic Analysis of 93 Aneurysms in 81 Patients

Characteristics_of_Posterior_Cerebral_ArteryNeurosurgery 75:134–144, 2014

Posterior cerebral artery (PCA) aneurysms are rare lesions. Because of their low incidence, the individual or institutional experience is usually limited.

OBJECTIVE: To identify specific anatomic features related to PCA aneurysms based on the analyses of pretreatment angiograms.

METHODS: We performed a detailed angiographic study of 81 patients with a diagnosis of 93 PCA aneurysms. Fifty-three patients underwent computed tomography angiography, 49 underwent digital subtraction angiography, and 6 underwent magnetic resonance angiography. Between 1980 and 2012, a total of 120 patients with 136 PCA aneurysms and 11 352 patients with 16 444 intracranial aneurysms were treated at our institutions.

RESULTS: There were 29 ruptured and 64 unruptured PCA aneurysms. The distribution of the aneurysms along the PCA segments was P1 (n = 39; 9 ruptured), P1/P2 junction (n = 25; 9 ruptured), P2 (n = 21; 5 ruptured), and P3 (n = 8; 6 ruptured). The median aneurysm size was 7 mm for the ruptured and 4 mm for the unruptured aneurysms. Saccular aneurysms (n = 69, 74%) had a typical projection for each location: P1 segment, upward (67%); P1/P2 junction, anterior/upward (80%); P2 segment, lateral (67%); and P3 segment, posterior (50%). Multiple aneurysms were seen in 43 patients. PCA aneurysms related to arteriovenous malformations were observed in 10 patients.

CONCLUSION: PCA aneurysms are infrequent lesions, often associated with multiple aneurysms and arteriovenous malformations and are fusiform in shape. Most ruptured PCA aneurysms are smaller than 10 mm and usually distally located. At each PCA segment, saccular PCA aneurysms have a typical dome orientation.

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Hemorrhage risks and functional outcomes of untreated brainstem cavernous malformations

brainstem cavernous malformations

J Neurosurg 121:32–41, 2014

Cerebral cavernous malformations have been studied widely, but the natural history of brainstem cavernous malformations (CMs) is not well defined, and hemorrhages caused by brainstem CMs are devastating. The goal of this study was to quantify the hemorrhage risks and functional outcomes of patients with brainstem CMs.

Methods. This prospective, longitudinal, cohort study included patients with brainstem CMs diagnosed between 1985 and 2012. The clinical courses of all patients were recorded. Predictors of hemorrhage and the overall untreated outcomes were evaluated.

Results. A total of 331 patients (46.5% female) were included, with a mean follow-up duration of 6.5 years. The annual hemorrhage rates in patients initially presenting with hemorrhage with (n = 215) or without (n = 34) focal neurological deficits were 15.9% and 12.4%, respectively. However, the annual hemorrhage rate was 8.7% in patients initially presenting without hemorrhage (n = 82). The risk factors for hemorrhage were female sex (hazard ratio [HR] 1.445, p = 0.041), prior hemorrhage (HR 1.277, p = 0.029), and perilesional edema (HR 1.830, p = 0.002). Overall, neurological function at the most recent assessment was improved compared with neurological function at diagnosis. Additionally, 307 patients (92.7%) improved or stabilized, 268 (81.0%) lived independently, and 95 (28.7%) completely recovered. Predictors favoring complete recovery were no prospective hemorrhage (HR 1.958, p = 0.001), younger age (HR 1.268, p = 0.001), and small lesion size (HR 1.578, p = 0.004).

Conclusions. Patients’ initial presentation predicts their prospective annual hemorrhage rate. This study suggests that several strong risk factors for hemorrhage and predictors of brainstem CM outcomes may enable clinicians to evaluate the potential hemorrhage risks of their patients and design personalized treatments.

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Suboptimal interventional conditions for the occlusion of ruptured intracranial aneurysms do not increase periprocedural complications and poor clinical outcomes


 aneurysms of the middle cerebral artery

Acta Neurochir (2014) 156:1267–1272

Occluding a ruptured intracranial aneurysm as early as possible may entail certain periprocedural conditions that compromise the outcome. The aim of the present study was to evaluate the effectiveness, safety, and clinical outcome of endovascular coiling procedures performed on an emergency basis under potentially suboptimal conditions, and to compare results with those from scheduled procedures under potentially optimal conditions.

Methods Interventions performed on 66 SAH patients were retrospectively analysed by classifying them into two groups: under emergency (within three hours fromdiagnosis or during non–standard working hours) or scheduled conditions. A binary logistic regression analysis was also performed to identify characteristics associated with poor outcomes.

Results No differences in effectiveness, periprocedural complications, or clinical outcomes were found between the two groups. Rebleeding was detected in 4.8 % of the emergency interventions and 2.2 % of the scheduled interventions. Multivariate analysis identified age and Hunt and Hess grade, but no conditions of treatment, as the factors associated to poor outcome.

Conclusion Suboptimal interventional conditions for occluding ruptured intracranial aneurysms, such as performing procedures outside of standard working hours or within three hours of diagnosis, do not result in increased periprocedural complications and poor clinical outcomes compared with scheduled procedures under potentially optimal conditions. These results suggest the need for treatment to be provided as soon as possible.

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Comparison of clinical and radiologic outcomes among stent-assisted, double-catheter, and balloon-assisted coil embolization of wide neck aneurysms

Comparison aneu

Acta Neurochir (2014) 156:1289–1295

Endovascular treatment of intracranial aneurysms can be technically challenging in cases of wide necks or unfavorable dome-to-neck ratio. Coils deployed without supporting devices may herniate from the aneurysm sac into the parent artery, causing thromboembolic complications or vessel occlusion. Therefore, alternative strategies for managing wide-necked aneurysms have been introduced such as stent-assisted coil embolization (SAC), balloon-assisted coil embolization (BAC), and double-catheter coil embolization (DCC).

Methods SAC, BAC, or DCC were used to treat 201 patients with 207 wide-neck aneurysms between 2008 and 2013. Initial occlusion rates, recanalization rates, and periprocedural complications were retrospectively evaluated. The mean follow-up periods for SAC,BAC, andDCCwere 16.2months, 11.6 months, and 14.3 months, respectively.

Results Clinical and anatomical analyses were conducted in 201 patients with 207 anuerysms. Complete occlusion rates of SAC, DCC, and BAC were 63.8 %, 46.7 %, and 63.2 %, respectively, and incomplete occlusion rates were 13.4 %, 15.5 %, 10.5 %, respectively (p value=0.798). No rebleeding or hemorrhage occurred after coil embolization. Recanalization rates did not differ among the SAC, DCC, and BAC groups (7.1 % vs. 11.1 % vs. 7.9 %, p value=0.696). Statistically insignificant results were observed in the rate of periprocedural complications among SAC, DCC, and BAC (11.0 % vs. 13.3 % vs. 15.8 %, p value=0.578).

Conclusions There were no significant differences in the recurrence rate and periprocedural complication rate, and no rebleeding or aneurysmal rupture after treatment. Sufficient occlusion rates were achieved with SAC, DCC, and BAC. Notably, DCC does not require the use of antiplatelet agents and achieves coil stability without compromising the parent artery or major branch. Thus, we believe that the doublecatheter technique was found to be a feasible and safe treatment modality for branching wide-neck aneurysms.

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Computational Fractal-Based Analysis of Brain Arteriovenous Malformation Angioarchitecture

Computational Fractal-Based Analysis of Brain Arteriovenous Malformation Angioarchitecture

Neurosurgery 75:72–79, 2014

Neuroimaging is the gold standard for diagnosis and follow-up of brain arteriovenous malformations (bAVMs), but no objective parameter has been validated for the assessment of the nidus angioarchitecture and for prognostication following treatment. The fractal dimension (FD), which is a mathematical parameter able to quantify the space-filling properties and roughness of natural objects, may be useful in quantifying the geometrical complexity of bAVMs nidus.

OBJECTIVE: To propose FD as a neuroimaging biomarker of the nidus angioarchitecture, which might be related to radiosurgical outcome.

METHODS: We retrospectively analyzed 54 patients who had undergone stereotactic radiosurgery for the treatment of bAVMs. The quantification of the geometric complexity of the vessels forming the nidus, imaged in magnetic resonance imaging, was assessed by means of the box-counting method to obtain the fractal dimension.

RESULTS: FD was found to be significantly associated with the size (P = .03) and volume (P , .001) of the nidus, in addition to several angioarchitectural parameters. A nonsignificant association between clinical outcome and FD was observed (area under the curve, 0.637 [95% confidence interval, 0.49-0.79]), indicative of a potential inverse relationship between FD and bAVM obliteration.

CONCLUSION: In our exploratory methodological research, we showed that the FD is an objective computer-aided parameter for quantifying the geometrical complexity and roughness of the bAVM nidus. The results suggest that more complex bAVM angioarchitecture, having higher FD values, might be related to decreased response to radiosurgery and that the FD of the bAVM nidus could be used as a morphometric neuroimaging biomarker.

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Internal Maxillary Artery-Middle Cerebral Artery Bypass: Infratemporal Approach for Subcranial-Intracranial (SC-IC) Bypass

Internal_Maxillary_Artery_Middle_Cerebral_Artery

Neurosurgery 75:87–95, 2014

Internal maxillary artery (IMax)–middle cerebral artery (MCA) bypass has been recently described as an alternative to cervical extracranial-intracranial bypass. This technique uses a “keyhole” craniectomy in the temporal fossa that requires a technically challenging end-to-side anastomosis.

OBJECTIVE: To describe a lateral subtemporal craniectomy of the middle cranial fossa floor to facilitate wide exposure of the IMax to facilitate bypass.

METHODS: Orbitozygomatic osteotomy is used followed by frontotemporal craniotomy and subsequently laterotemporal fossa craniectomy, reaching its medial border at a virtual line connecting the foramen rotundum and foramen ovale. The IMax was identified by using established anatomic landmarks, neuronavigation, and micro Doppler probe (Mizuho Inc. Tokyo, Japan). Additionally, we studied the approach in a cadaveric specimen in preparation for microsurgical bypass.

RESULTS: There were 4 cases in which the technique was used. One bypass was performed for flow augmentation in a hypoperfused hemisphere. The other 3 were performed as part of treatment paradigms for giant middle cerebral artery aneurysms. Vein grafts were used in all patients. The proximal anastomosis was performed in an end-toside fashion in 1 patient and end-to-end in 3 patients. Intraoperative graft flow measured with the Transonic flow probe ranged from 20 to 60 mL/min. Postoperative angiography demonstrated good filling of the graft with robust distal flow in all cases. All patients tolerated the procedure well.

CONCLUSION: IMax to middle cerebral artery subcranial-intracranial bypass is safe and efficacious. The laterotemporal fossa craniectomy technique resulted in reliable identification and wide exposure of the IMax, facilitating the proximal anastomosis.

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Contralateral Interhemispheric Approach to Deep-Seated Cavernous Malformations

Contralateral Interhemispheric Approach to Deep-Seated Cavernous Malformations (1)

Neurosurgery 75:80–86, 2014

Deep-seated periventricular cavernous malformations of the basal ganglia or thalamus can be approached via an interhemispheric craniotomy. OBJECTIVE: To determine surgical efficacy and clinical outcomes of the contralateral interhemispheric approach.

METHODS: Retrospective chart review was performed on patients undergoing an interhemispheric approach for the resection of deep-seated cavernous malformation by the senior author (R.F.S.) between 2005 and 2013. Demographic data and clinical outcomes were reviewed. Pre- and postoperative imaging were analyzed for lesion location, size, associated venous anomaly, proximity to ventricle, and presence of residual.

RESULTS: Twenty-one patients underwent a contralateral interhemispheric-transventricular approach, 7 patients had a contralateral interhemispheric-transcingulate approach and 3 patients had a contralateral interhemispheric-transchoroidal approach. Mean age was 40.1 years, and the majority were female (58.1%). Mean maximum cavernoma diameter was 1.97 cm, and 43.8% reached the surface of the ventricle. Average follow-up was 8.9 months, with complete resection achieved in 96.8% of patients. At last follow-up, 61.3% of patients remained stable and 29.0% had improved. Of the patients, 6.5% experienced transient weakness that resolved at last follow-up, and 1 patient (3.2%) had short-term memory problems. There were no surgical mortalities.

CONCLUSION: The contralateral interhemispheric approach is a safe, clinically well tolerated, and surgically efficacious approach to deep-seated cavernomas.

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Brainstem cavernoma surgery with the support of pre and postoperative diffusion tensor imaging

Brainstem cavernoma surgery

Neurosurg Rev (2014) 37:481–492

The spatial complexity of highly vulnerable structures makes surgical resection of brainstem cavernomas (BSC) a challenging procedure. Diffusion tensor imaging (DTI) allows for the visualization of white matter tracts and enables a better understanding of the anatomical location of corticospinal and sensory tracts before and after surgery.

We investigated the feasibility and clinical usefulness of DTI-based fiber tractography in patients with BSC.Pre- and postoperative DTI visualization of corticospinal and sensory tracts were retrospectively analyzed in 23 individuals with BSC. Preoperative and postoperative DTIfiber accuracy were associated to the neurological findings.

Preoperatively, the corticospinal tracts were visualized in 90%of the cases and the sensory tracts were visualized in 74 % of the cases. Postoperatively, the corticospinal tracts were visualized in 97 % of the cases and the sensory tracts could be visualized in 80 % of the cases. In all cases, the BSC had caused displacement, thinning, or interruption of the fiber tracts to various degrees. Tract visualization was associated with pre- and postoperative neurological findings. Postoperative damage of the corticospinal tracts was observed in two patients. On follow-up, the Patzold Rating (PR) improved in 19 out of 23 patients (83 %, p= 0.0002).

This study confirms that DTI tractography allows accurate and detailed white matter tract visualization in the brainstem, even when an intraaxial lesion affects this structure. Furthermore, visualizing the tracts adjacent to the lesion adds to our understanding of the distorted intrinsic brainstem anatomy and it may assists in planning the surgical approach in specific cases.

 

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The “Squeezing Maneuver” in Microsurgical Clipping of Intracranial Aneurysms Assisted by Indocyanine Green Videoangiography

The “Squeezing Maneuver” in Microsurgical Clipping of Intracranial Aneurysms Assisted by Indocyanine Green Videoangiography

Operative Neurosurgery 10:208–213, 2014

Indocyanine green videoangiography (ICGV) is becoming routine in intracranial aneurysm surgery to assess intraoperatively both sac obliteration and vessel patency after clipping. However, ICGV-derived data have been reported to be misleading at times. We recently noted that a simple intraoperative maneuver, the “squeezing maneuver,” allows the detection of deceptive ICGV data on aneurysm exclusion and allows potential clip repositioning. The squeezing maneuver is based on a gentle pinch of the dome of a clipped aneurysm when ICGV documents its apparent exclusion.

OBJECTIVE: To present the surgical findings and the clinical outcome of this squeezing maneuver.

METHODS: Data from 23 consecutive patients affected by intracranial aneurysms who underwent the squeezing maneuver were analyzed retrospectively. The clip was repositioned in all cases when the dyeing of the sac was visualized after the maneuver.

RESULTS: In 22% of patients, after an initial ICGV showing the aneurysm exclusion after clipping, the squeezing maneuver caused the prompt dyeing of the sac; in all cases, the clip was consequently repositioned. A calcification/atheroma of the wall/neck was predictive of a positive maneuver (P = .001). The aneurysm exclusion rate at postoperative radiological findings was 100%.

CONCLUSION: With the limits of our small series, the squeezing maneuver appears helpful in the intraoperative detection of misleading ICGV data, mostly when dealing with aneurysms with atheromatic and calcified walls.

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Indocyanine Green Angiography in the Surgical Management of Cerebral Arteriovenous Malformations

Indocyanine Green Angiography in the Surgical Management of Cerebral Arteriovenous Malformations

Operative Neurosurgery 10:246–251, 2014

Indocyanine green (ICG) angiography is commonly used to map the vascular configuration of cerebral arteriovenous malformations (AVMs) during resection.

OBJECTIVE: To determine whether ICG improves rates of resection and clinical outcomes.

METHODS: A retrospective chart review was done for all patients undergoing resection of an AVM by the senior author (R.F.S.) between 2007 and 2011. Operative reports, hospital records, and radiographic imaging were used to determine the use of ICG, the incidence of residual disease, and clinical outcomes.

RESULTS: A total of 130 cases (56 ICG, 74 non-ICG) were identified. Average AVM grade (2.2 vs 2.4) and size (2.7 vs 2.7 cm) were similar between the ICG and non-ICG groups, respectively. ICG was more often used when the AVM nidus was close to the cortical surface (71.4% vs 17.6%; P = .001) or lobar (82.1% vs 54.1%; P = .008). Eighteen patients (13.8%) were noted to have residual disease. Reoperation rates and change in modified Rankin Scale score were not different between the 2 groups (12.5% vs 14.9%, P = .8; 0.6 vs 0.4, P = .17). There were no ICG-attributable complications.

CONCLUSION: ICG videoangiography is a quick and safe method of intraoperatively mapping the angioarchitecture of superficial AVMs, but it is less helpful for deep-seated lesions. This modality alone does not improve the identification of residual disease or clinical outcomes. Surgeon experience with extensive study of preoperative vascular imaging is paramount to achieving acceptable clinical outcomes. Formal angiography remains the gold standard for the evaluation of AVM obliteration.

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Acute subdural hematoma from bridging vein rupture: a potential mechanism for growth

Acute subdural hematoma from bridging vein rupture- a potential mechanism for growth

J Neurosurg 120:1378–1384, 2014

Most acute subdural hematomas (ASDHs) develop after rupture of a bridging vein or veins. The anatomy of the bridging vein predisposes to its tearing within the border cell layer of the dura mater. Thus, the subdural hematoma actually forms within the dura. The hematoma grows by continued bleeding into the border cell layer. However, the venous pressure would not be expected to cause a large hematoma. Therefore, some type of mechanism must account for the hematoma’s expansion. Cerebral venous pressure (CVP) has been demonstrated in animal models to be slightly higher than intracranial pressure (ICP), and CVP tracks the ICP as pressure variations occur. The elevation of CVP as the ICP increases is thought to result from an increase in outflow resistance of the terminal portion of the bridging veins. This probably results from a Starling resistor model or, less likely, from a muscular sphincter.

A hypothesis is derived to explain the mechanism of ASDH enlargement. Tearing of one or more bridging veins causes these vessels to bleed into the dural border cell layer. Subsequent ICP elevation from the ASDH, cerebral swelling, or other cause results in elevation of the CVP by increased outflow resistance in the intact bridging veins. The increased ICP causes further bleeding into the hematoma cavity via the torn bridging veins. Thus, the ASDH enlarges via a positive feedback mechanism. Enlargement of an ASDH would cease as blood within the hematoma cavity coagulates. This would stop the dissection of the dural border cell layer, and pressure within the hematoma cavity would equalize with that in the torn bridging vein or veins.

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