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Mahsa Dabagh, Priya Nair, John Gounley, David Frakes, L. Fernando Gonzalez, and Amanda Randles

The growth of cerebral aneurysms is linked to local hemodynamic conditions, but the driving mechanisms of the growth are poorly understood. The goal of this study was to examine the association between intraaneurysmal hemodynamic features and areas of aneurysm growth, to present the key hemodynamic parameters essential for an accurate prediction of the growth, and to gain a deeper understanding of the underlying mechanisms. Patient-specific images of a growing cerebral aneurysm in 3 different growth stages acquired over a period of 40 months were segmented and reconstructed. A unique aspect of this patient-specific case study was that while one side of the aneurysm stayed stable, the other side continued to grow. This unique case enabled the authors to examine their aims in the same patient with parent and daughter arteries under the same inlet flow conditions. Pulsatile flow in the aneurysm models was simulated using computational fluid dynamics and was validated with in vitro experiments using particle image velocimetry measurements. The authors’ detailed analysis of intrasaccular hemodynamics linked the growing regions of aneurysms to flow instabilities and complex vortex structures. Extremely low velocities were observed at or around the center of the unstable vortex structure, which matched well with the growing regions of the studied cerebral aneurysm. Furthermore, the authors observed that the aneurysm wall regions with a growth greater than 0.5 mm coincided with wall regions of lower (< 0.5 Pa) time-averaged wall shear stress (TAWSS), lower instantaneous (< 0.5 Pa) wall shear stress (WSS), and high (> 0.1) oscillatory shear index (OSI). To determine which set of parameters can best identify growing and nongrowing aneurysms, the authors performed statistical analysis for consecutive stages of the growing CA. The results demonstrated that the combination of TAWSS and the distance from the center of the vortical structure has the highest sensitivity and positive predictive value, and relatively high specificity and negative predictive value. These findings suggest that an unstable, recirculating flow structure within the aneurysm sac created in the region adjacent to the aneurysm wall with low TAWSS may be introduced as an accurate criterion to explain the hemodynamic conditions predisposing the aneurysm to growth. The authors’ findings are based on one patient’s data set, but the study lays out the justification for future large-scale verification. The authors’ findings can assist clinicians in differentiating stable and growing aneurysms during preinterventional planning.

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Charles J. Prestigiacomo, Matthew J. Gounis, L. Fernando Gonzalez, and Juhana Frösen

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Richard Dalyai, Robert M. Starke, Nohra Chalouhi, Thana Theofanis, Christopher Busack, Pascal Jabbour, L. Fernando Gonzalez, Robert Rosenwasser, and Stavropoula Tjoumakaris

Object

Cigarette smoking has been well established as a risk factor in vascular pathology, such as cerebral aneurysms. However, tobacco’s implications for patients with cerebral arteriovenous malformations (AVMs) are controversial. The object of this study was to identify predictors of AVM obliteration and risk factors for complications.

Methods

The authors conducted a retrospective analysis of a prospectively maintained database for all patients with AVMs treated using surgical excision, staged endovascular embolization (with N-butyl-cyanoacrylate or Onyx), stereotactic radiosurgery (Gamma Knife or Linear Accelerator), or a combination thereof between 1994 and 2010. Medical risk factors, such as smoking, abuse of alcohol or intravenous recreational drugs, hypercholesterolemia, diabetes mellitus, hypertension, and coronary artery disease, were documented. A multivariate logistic regression analysis was conducted to detect predictors of periprocedural complications, obliteration, and posttreatment hemorrhage.

Results

Of 774 patients treated at a single tertiary care cerebrovascular center, 35% initially presented with symptomatic hemorrhage and 57.6% achieved complete obliteration according to digital subtraction angiography (DSA) or MRI. In a multivariate analysis a negative smoking history (OR 1.9, p = 0.006) was a strong independent predictor of AVM obliteration. Of the patients with obliterated AVMs, 31.9% were smokers, whereas 45% were not (p = 0.05). Multivariate analysis of obliteration, after controlling for AVM size and location (eloquent vs noneloquent tissue), revealed that nonsmokers were more likely (0.082) to have obliterated AVMs through radiosurgery. Smoking was not predictive of treatment complications or posttreatment hemorrhage. Abuse of alcohol or intravenous recreational drugs, hypercholesterolemia, diabetes mellitus, and coronary artery disease had no discernible effect on AVM obliteration, periprocedural complications, or posttreatment hemorrhage.

Conclusions

Cerebral AVM patients with a history of smoking are significantly less likely than those without a smoking history to have complete AVM obliteration on follow-up DSA or MRI. Therefore, patients with AVMs should be strongly advised to quit smoking.

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Vijay Agarwal, Ali Zomorodi, Pascal Jabbour, Nohra Chalouhi, Stavropoula Tjoumakaris, Ranjith Babu, Adam Back, and L. Fernando Gonzalez

We present a case of a patient with rapid loss of motor strength in his lower extremities. He became bedridden with bowel and bladder incontinence, and developed saddle anesthesia. MRI of the lumbar spine showed edema in the conus medullaris and multiple flow voids within the spinal canal. A spinal angiogram showed a dorsal Type I spinal AVF. This was treated successfully with Onyx 18 (eV3, Irvine, CA). The patient showed rapid post-procedure improvement, and at discharge from the hospital to a rehabilitation center he was fully ambulatory. At 3-year follow-up, the patient was found to ambulate without difficulty. He also had improved saddle anesthesia, and he was voiding spontaneously. There was no evidence of flow voids on repeat MRI of the lumbar spine.

The video can be found here: http://youtu.be/SDYNIGNQIW8.

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Vijay Agarwal, Ali Zomorodi, Cameron Mcdougal, Ranjith Babu, Adam Back, and L. Fernando Gonzalez

We present the case of a balloon-assisted, stent-supported coil embolization of a basilar tip aneurysm. Initially, a balloon extending from the basilar artery into the right PCA was placed. However, even with a more proximal purchase, coils were found to impinge on the left PCA. Subsequently, a transcirculation approach was performed, where the left posterior communicating artery was utilized as a conduit for balloon support and the coils were embolized from the ipsilateral vertebral artery. However, after this transcirculation approach was completed, there was a coil tail extruding from the aneurysm. The balloon was then removed over an exchange wire and a horizontal stent advanced, spanning the entire neck of the aneurysm, eliminating the extruded coil.

The video can be found here: http://youtu.be/bMbtZoPnYvo.

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Nohra Chalouhi, Stavropoula Tjoumakaris, Robert M. Starke, David Hasan, Nimrita Sidhu, Saurabh Singhal, Shannon Hann, L. Fernando Gonzalez, Robert Rosenwasser, and Pascal Jabbour

Object

Endovascular therapy has become a widely used method for achieving arterial recanalization in patients who are ineligible for intravenous thrombolysis or those in whom it is unsuccessful. Young stroke patients with large vessel occlusions may particularly benefit from endovascular intervention. This study aims to assess the authors' experience with the use of modern endovascular techniques to treat young patients (≤ 55 years old) with acute ischemic stroke and large vessel occlusions.

Methods

Young patients (≤ 55 years old) undergoing endovascular intervention for acute ischemic stroke at the authors' institution were identified from a prospectively maintained database. Only those patients with a confirmed large vessel occlusion were included. Modified Rankin Scale (mRS) scores were determined at 90 days during a follow-up visit. A multivariate analysis was performed to determine predictors of outcome (mRS score 0–2).

Results

A total of 45 patients met the inclusion criteria. The mean age of the patients in this series was 45 ± 9.6 years. The mean admission NIH Stroke Scale score was 14.1 ± 5 (median 13.5). Mechanical thrombectomy was performed using the Solitaire FR device in 13 (29%) patients and the Merci/Penumbra systems in 32 (71%) patients. The rate of successful recanalization (Thrombolysis In Myocardial Infarction [TIMI] scale Grade II–III) was 93% (42/45). Only 1 patient (2.2%) had a symptomatic intracranial hemorrhage following intervention. One patient (2.2%) sustained a vessel perforation intraoperatively. The rate of 90-day favorable outcome (mRS score 0–2) was 77.5% and the rate of 90-day satisfactory outcome (mRS score 0–3) was 90%. The 90-day mortality rate was 7.5%. In multivariate analysis, postprocedure TIMI grade was the only statistically significant independent predictor of 90-day outcome (OR 3.3, 95% CI 1.01–1.19; p = 0.05).

Conclusions

The results of this study demonstrate that endovascular therapy provides remarkably high rates of arterial recanalization and favorable outcomes in young patients with acute ischemic stroke and large vessel occlusions. These findings support aggressive interventional strategies in these patients. Randomized, controlled trials reflecting modern acute ischemic stroke treatment will be needed to confirm the findings of this study.

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Nohra Chalouhi, Aaron S. Dumont, Stavropoula Tjoumakaris, L. Fernando Gonzalez, Jurij R. Bilyk, Ciro Randazzo, David Hasan, Richard T. Dalyai, Robert Rosenwasser, and Pascal Jabbour

Object

Endovascular therapy is the primary treatment option for carotid-cavernous fistulas (CCFs). Operative cannulation of the superior ophthalmic vein (SOV) provides a reasonable alternative route to the cavernous sinus when all transvenous and transarterial approaches have been unsuccessful. The role of the liquid embolic agent Onyx in the management of CCFs has not been well documented, especially when using an SOV approach. The purpose of this study is to assess the safety and efficacy of Onyx embolization of CCFs through a surgical cannulation of the SOV.

Methods

The authors retrospectively reviewed all patients with CCFs who were treated with Onyx through an SOV approach between April 2009 and April 2011. Traditional endovascular approaches had failed in all patients.

Results

A total of 10 patients were identified, 1 with a Type A CCF, 5 with a Type B CCF, and 4 with a Type D CCF. All fistulas were embolized in 1 session. Onyx was the sole embolic agent used in 7 cases and was combined with coils in 3 other cases. Complete obliteration was achieved in 8 patients and a significant reduction in fistulous flow was achieved in 2 patients, which later progressed to near-complete occlusion on angiographic follow-up. All patients experienced a complete clinical recovery with excellent cosmetic results and were free from recurrence at their latest clinical follow-up evaluations.

Conclusions

Onyx embolization is an excellent therapy for CCFs in general, and through an SOV approach in particular. Direct operative cannulation of the SOV followed by Onyx embolization may be the best treatment option in patients with CCFs when all other endovascular approaches have been exhausted.

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L. Fernando Gonzalez, Nohra Chalouhi, Stavropoula Tjoumakaris, Pascal Jabbour, Aaron S. Dumont, and Robert H. Rosenwasser

Object

Multiple approaches have been used to treat carotid-cavernous fistulas (CCFs). The transvenous approach has become a popular and effective route. Onyx is a valuable tool in today's endovascular armamentarium. The authors describe the use of a balloon-assisted technique in the treatment of CCFs with Onyx and assess its feasibility, utility, and safety.

Methods

The authors searched their prospectively maintained database for CCFs embolized using Onyx with the assistance of a compliant balloon placed in the internal carotid artery (ICA).

Results

Five patients were treated between July 2009 and July 2011 at the authors' institution. A balloon helped to identify the fistulous point, served as a buttress for coils, protected from inadvertent arterial embolizations, and prevented Onyx and coils from obscuring the ICA during the course of embolization. No balloon-related complications were noted in any of the 5 cases. All 5 fistulas were completely obliterated at the end of the procedure. Four patients had available clinical follow-ups, and all 4 showed reversal of nerve palsies.

Conclusions

Balloon-assisted Onyx embolization of CCFs offers a powerful combination that prevents inadvertent migration of the embolic material into the arterial system, facilitates visualization of the ICA, and serves as a buttress for coils deployed in the cavernous sinus through the fistulous point. Despite adding another layer of technical complexity, an intraarterial balloon can provide valuable assistance in the treatment of CCFs.

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Nohra Chalouhi, Rohan Chitale, Pascal Jabbour, Stavropoula Tjoumakaris, Aaron S. Dumont, Robert Rosenwasser, and L. Fernando Gonzalez

Given that relatives of patients with intracranial aneurysms (IAs) or subarachnoid hemorrhage have a greater risk of harboring an aneurysm, family screening has become a common practice in neurosurgery. Unclear data exist regarding who should be screened and at what age and interval screening should occur. Multiple factors including the natural history of IAs, the risk of treatment, the cost of screening, and the psychosocial impact of finding an aneurysm should be taken into account when family screening is considered. In this paper, the authors review the current literature regarding risk factors and natural history of sporadic and familial aneurysms. Based on these data the authors assess current recommendations for screening and propose their own recommendations.