Alejandro Santillan

Embolization and radiosurgery for arteriovenous malformations

The treatment of arteriovenous malformations (AVMs) requires a multidisciplinary management including microsurgery, endovascular embolization, and stereotactic radiosurgery (SRS). This article reviews the recent advancements in the multimodality treatment of patients with AVMs using endovascular neurosurgery and SRS. We describe the natural history of AVMs and the role of endovascular and radiosurgical treatment as well as their interplay in the management of these complex vascular lesions. Also, we present some representative cases treated at our institution.

Endovascular Embolization of Iatrogenic Lumbar Artery Pseudoaneurysm Following Extreme Lateral Interbody Fusion (XLIF)

Iatrogenic lumbar artery pseudoaneurysm is a very rare complication of spinal surgery. To the best of our knowledge, this is the first report of a lumbar artery pseudoaneurysm after extreme lateral interbody fusion (XLIF). The lesion was diagnosed by catheter spinal angiography and was effectively treated with embolization.

Endovascular management of intracranial dural arteriovenous fistulas: A review

Dural arteriovenous fistulas (DAVFs) are rare pathological entities presenting with a diverse clinical course, ranging from benign to life-threatening. Digital subtraction angiography remains the gold standard in the diagnosis of clinically suspected DAVFs. This article reviews the ethiopathogenesis, natural history, classification systems, clinical and angiographic features, and the current treatment strategies for these complex lesions. The management of DAVFs may include conservative treatment, endovascular intervention, microsurgery, and stereotactic radiosurgery. A multidisciplinary approach involving a neurosurgeon, interventional neuroradiologist, and neurologist is required before considering any type of treatment modality. The indication for the best therapeutic alternative must be individualized for each patient.

Balloon-assisted coil embolization of intracranial aneurysms is not associated with increased periprocedural complications

Background The balloon-assisted coil embolization (BACE) technique represents an effective tool for the treatment of complex wide-necked intracranial aneurysms; however, its safety is a matter of debate. This study presents the authors institutional experience regarding the safety of the BACE technique. Methods 428 consecutive patients with 491 intracranial aneurysms (274 acutely ruptured and 217 unruptured) treated with conventional coil embolization (CCE) or with BACE were retrospectively reviewed. All procedure-related adverse events were reported, regardless of clinical outcome. Thromboembolic events, intraprocedural aneurysm ruptures, device-related complications, morbidity and mortality were compared between the CCE and BACE groups. Results The total rate of procedural and periprocedural adverse events was 9.6% (47/491 embolizations). Thromboembolic events, intraprocedural aneurysmal rupture and device-related complications occurred in 2.4%, 3.9% and 3.3% of procedures, respectively. The risk of thromboembolic events and device-related problems was similar between the CCE and BACE groups. A trend towards a higher risk of intraprocedural aneurysm rupture was observed in the BACE group (not statistically significant). The total cumulative morbidity and mortality for both groups was 2.6% (11/428 patients) and there was no statistically significant difference in the morbidity, mortality and cumulative morbidity and mortality rates between the two groups. Conclusion In this series of patients with acutely ruptured and unruptured aneurysms, the BACE technique allowed treatment of aneurysms with unfavorable anatomic characteristics without increasing the incidence of procedural complications.

Orthotopic glioblastoma stem-like cell xenograft model in mice to evaluate intra-arterial delivery of bevacizumab: From bedside to bench

Bevacizumab (BV), a humanized monocolonal antibody directed against vascular endothelial growth factor (VEGF), is a standard intravenous (IV) treatment for recurrent glioblastoma multiforme (GBM), that has been introduced recently as an intra-arterial (IA) treatment modality in humans. Since preclinical models have not been reported, we sought to develop a tumor stem cell (TSC) xenograft model to investigate IA BV delivery in vivo. Firefly luciferase transduced patient TSC were injected into the cortex of 35 nude mice. Tumor growth was monitored weekly using bioluminescence imaging. Mice were treated with either intraperitoneal (IP) or IA BV, with or without blood-brain barrier disruption (BBBD), or with IP saline injection (controls). Tumor tissue was analyzed using immunohistochemistry and western blot techniques. Tumor formation occurred in 31 of 35 (89%) mice with a significant signal increase over time (p=0.018). Post mortem histology revealed an infiltrative growth of TSC xenografts in a similar pattern compared to the primary human GBM. Tumor tissue analyzed at 24 hours after treatment revealed that IA BV treatment with BBBD led to a significantly higher intratumoral BV concentration compared to IA BV alone, IP BV or controls (p<0.05). Thus, we have developed a TSC-based xenograft mouse model that allows us to study IA chemotherapy. However, further studies are needed to analyze the treatment effects after IA BV to assess tumor progression and overall animal survival.

Transluminal balloon angioplasty for symptomatic distal vasospasm refractory to medical therapy in patients with aneurysmal subarachnoid hemorrhage.

BACKGROUND:Cerebral vasospasm (VSP) is a major cause of morbidity and mortality associated with subarachnoid hemorrhage. The current endovascular paradigm for VSP refractory to medical therapy is to perform angioplasty for proximal vessel VSP and vasodilator infusion for distal vessel VSP. OBJECTIVE:To report our experience with a large series of balloon angioplasty for distal VSP refractory to medical therapy in patients with aneurysmal subarachnoid hemorrhage. METHODS:This was a retrospective series of 32 patients with subarachnoid hemorrhage and symptomatic VSP refractory to medical therapy who were treated with balloon angioplasty for distal vessel VSP. Immediate angiographic results, procedure-related complications, and clinical outcomes were assessed. RESULTS:From September 2001 to January 2010, 32 patients with symptomatic VSP refractory to medical therapy underwent angioplasty for distal arterial VSP. There were 26 women (81.3%); patients were 29 to 67 years of age. A total of 175 vessels were angioplastied (95 proximal and 80 distal). The only complication was rupture of an incompletely clipped aneurysm that was treated by immediate coiling and did not result in any clinical worsening. Repeated treatment was needed for 6 arteries (6 of 80, 7.5%). There were no procedure-related symptomatic complications. Good outcomes (modified Rankin Scale score ≤ 2) were observed in 23 of 28 patients (82.1%) with follow-up. CONCLUSION:Balloon angioplasty for distal VSP is safe and effective and decreases the need for repeated intraarterial treatments seen with infusion of vasodilator.

Early endovascular management of oculomotor nerve palsy associated with posterior communicating artery aneurysms.

Palsy of the third cranial nerve (oculomotor nerve, CNIII) is a well-known clinical presentation of posterior communicating artery (P-com) aneurysm. We report a series of 11 patients with partial or complete third nerve palsy secondary to P-com aneurysm. All were treated with endovascular embolization within seven days of symptom onset. Third nerve palsy symptoms resolved in 7/11 (64%), improved in 2/11 (18%) and did not change in 2/11 (18%) patients

Bare platinum vs matrix detachable coils for the endovascular treatment of intracranial aneurysms: a multivariate logistic regression analysis and review of the literature.

BACKGROUND:Despite increasing acceptance of endovascular coiling for treating intracranial aneurysms, incomplete occlusion remains a limitation. Attempts to reduce recanalization have prompted creation of polyglycolic/polylactic acid-coated (Matrix) coils shown to improve neointima formation; however, previous publications demonstrate conflicting results regarding their efficacy. Few studies account for factors influencing recurrence, and only 4 studies include bare platinum (BP) coil control groups. OBJECTIVE:To compare initial and short- and mid-term occlusion as well as retreatment rates using Matrix compared with BP coils. METHODS:Retrospective review of patients undergoing coiling of cerebral aneurysms from 2001 to 2005 was performed. Analysis included a multivariate logistic regression model designed to detect a 35% absolute difference in initial occlusion between coil treatment groups with 80% power. RESULTS:Complete initial occlusion was achieved in 64% of BP (n = 45) and 63% of Matrix (n = 56) cases (P = 1.0). Follow-up occlusion rates in the short term and mid term were 52% and 60%, respectively, for BP cases and 42% and 67%, respectively, for Matrix cases (P = .24 and P = .38, respectively). After adjusting for size, morphology, volumetric packing density, location, rupture, and balloon remodeling, no difference in initial and subsequent occlusion or retreatment rates for BP coils versus Matrix coils was appreciated. CONCLUSION:After controlling for factors influencing recanalization, this investigation failed to show a significant difference between coil groups.

Endovascular management of spinal dural arteriovenous fistulas

Spinal dural arteriovenous fistulas (SDAVFs) represent the most frequent spinal arteriovenous malformation and have an ominous natural history if left untreated. In the present review, we describe the spinal vascular anatomy, pathophysiology and clinical manifestations of SDAVFs, and the current role of endovascular embolization in this type of lesion.

Predicting postoperative hydrocephalus in 227 patients with skull base meningioma

OBJECTnSome patients develop communicating hydrocephalus after meningioma surgery, and this can develop into a serious clinical condition. However, this has rarely been addressed in the literature. Therefore, the authors sought to determine predictive patient variables for the occurrence of postoperative hydrocephalus following skull base meningioma surgery.nnnMETHODSnFor this purpose, the authors retrospectively analyzed all patients who underwent resection of intracranial meningiomas between 1998 and 2009 at the Department of Neurosurgery, University Hospital Zurich, Switzerland. Of 594 patients with meningioma, 227 (38%) had a lesion located at the skull base, and thus were included for analysis. The following patient variables were examined: demographic data (age and sex); tumor number (solitary vs multiple); tumor side and localization within the skull base region (anterior, medial, posterior); infiltration of the cavernous sinus; compression of the optic channel/optic nerve; tumor volume; preoperative embolization (yes/no); duration of surgery; Simpson grade of resection; histopathological features (WHO grade); number of surgeries (single vs multiple); preoperative embolization; duration of hospital stay; tumor recurrence; use of an artificial dural substitute; postoperative infection rate; and clinical outcome (Glasgow Outcome Scale score at discharge and at 3 months, and vital status at last follow-up). Hierarchical clustering, factor analysis, and stepwise regression models revealed a ranking list for the top predictive variables for the occurrence of postoperative hydrocephalus.nnnRESULTSnA total of 35 patients (5.9%) of the cohort of 594 developed communicating postoperative hydrocephalus, with no patient manifesting obstructive hydrocephalus. Of these 35 patients, 18 had a meningioma located at the skull base (18 [7.9%] of 227), in contrast to 17 patients with meningiomas in other locations (17 [4.6%] of 367). The following patient variables correlated with the occurrence of hydrocephalus, as defined by factor analysis: age, duration of surgery, duration of hospital stay, tumor volume, postoperative infection, and preoperative embolization. A stepwise regression analysis of the latter variables identified 2 variables as significantly predictive: age (p = 0.0012) and duration of surgery (p = 0.0013).nnnCONCLUSIONSnIn this study, the incidence of communicating postoperative hydrocephalus was almost twice as high in patients with skull base lesions as in patients with meningiomas in other locations. Patient age, duration of surgery, duration of hospital stay, tumor volume, postoperative infection, and preoperative embolization were associated with the occurrence of hydrocephalus. In the statistical prediction model, patient age and duration of surgery were the most significant predictors of postoperative hydrocephalus after skull base meningioma surgery.