Saul F. Morales-Valero

Are parenchymal AVMs congenital lesions

A long-held dogma in neurosurgery is that parenchymal arteriovenous malformations (AVMs) are congenital. However, there is no strong evidence supporting this theory. An increasing number of documented cases of de novo formation of parenchymal AVMs cast doubt on their congenital nature and suggest that indeed the majority of these lesions may form after birth. Further evidence suggesting the postnatal development of parenchymal AVMs comes from the exceedingly rare diagnosis of these lesions in utero despite the widespread availability of high-resolution imaging modalities such as ultrasound and fetal MRI. The exact mechanism of AVM formation has yet to be elucidated, but most likely involves genetic susceptibility and environmental triggering factors. In this review, the authors report 2 cases of de novo AVM formation and analyze the evidence suggesting that they represent an acquired condition.

Rescue treatment of thromboembolic complications during endovascular treatment of cerebral aneurysms: a meta-analysis.

The authors evaluated the results reported in 23 studies that included 516 patients in whom different drugs were used for rescue therapy in thromboembolic complications during endovascular treatment of intracranial aneurysms. The literature shows that rescue therapy with thrombolytic agents resulted in significantly more morbidity than rescue therapy with glycoprotein IIb/IIIa inhibitors. Tirofiban/eptifibatide resulted in significantly higher recanalization rates compared with abciximab. BACKGROUND AND PURPOSE: Intraprocedural thrombus formation during endovascular treatment of intracranial aneurysms is often treated with glycoprotein IIb/IIIa inhibitors and, in some instances, fibrinolytic therapy. We performed a meta-analysis evaluating the safety and efficacy of GP IIb/IIIa inhibitors compared with fibrinolysis. We also evaluated the safety and efficacy of abciximab, an irreversible inhibitor, compared with tirofiban and eptifibatide, reversible inhibitors of platelet function. MATERIALS AND METHODS: We performed a comprehensive literature search for studies on rescue therapy for intraprocedural thromboembolic complications with glycoprotein IIb/IIIa inhibitors or fibrinolysis during endovascular treatment of intracranial aneurysms. We studied rates of periprocedural stroke/hemorrhage, procedure-related morbidity and mortality, immediate arterial recanalization, and long-term good clinical outcome. Event rates were pooled across studies by using random-effects meta-analysis. RESULTS: Twenty-three studies with 516 patients were included. Patients receiving GP IIb/IIIa inhibitors had significantly lower perioperative morbidity from stroke/hemorrhage compared with those treated with fibrinolytics (11.0%; 95% CI, 7.0%–16.0% versus 29.0%; 95% CI, 13.0%–55.0%; P = .04) and were significantly less likely to have long-term morbidity (16.0%; 95% CI, 11.0%–21.0% versus 35.0%; 95% CI, 17.0%–58.0%; P = .04). There was a trend toward higher recanalization rates among patients treated with glycoprotein IIb/IIIa inhibitors compared with those treated with fibrinolytics (72.0%; 95% CI, 64.0%–78.0% versus 50.0%; 95% CI, 28.0%–73.0%; P = .08). Patients receiving tirofiban or eptifibatide had significantly higher recanalization rates compared with those treated with abciximab (83.0%; 95% CI, 68.0%–91.0% versus 66.0%; 95% CI, 58.0%–74.0%; P = .05). No difference in recanalization was seen in patients receiving intra-arterial (77.0%; 95% CI, 66.0%–85.0%) or intravenous GP IIb/IIIa inhibitors (70.0%; 95% CI, 57.0%–80.0%, P = .36). CONCLUSIONS: Rescue therapy with thrombolytic agents resulted in significantly more morbidity than rescue therapy with glycoprotein IIb/IIIa inhibitors. Tirofiban/eptifibatide resulted in significantly higher recanalization rates compared with abciximab.

Endoscopic endonasal approach for craniovertebral junction pathology: a review of the literature.

OBJECT The transoral approach is the gold standard for ventral decompression of the brainstem caused by craniovertebral junction (CVJ) pathology. This approach is often associated with significant morbidity, related to swallowing and respiratory complications. The endoscopic endonasal approach was introduced to reduce the rate of these complications. However, the exact role of this approach in the treatment of CVJ pathology is not well defined. METHODS A comprehensive literature search was performed to identify series of patients with pathology of the CVJ treated via the endoscopie endonasal approach. Data on patient characteristics, indications for treatment, complications, and outcome were obtained and analyzed. RESULTS Twelve studies involving 72 patients were included. The most common indications for treatment were rheumatoid pannus (38.9%) and basilar invagination (29.2%). Cerebrospinal fluid leak was found in 18% of cases intraoperatively and 4.2% of cases postoperatively. One case of meningitis complicated by sepsis and death represents the procedure-related mortality of 1.4%. Of the patients without preoperative swallowing impairment, 95% returned to oral feeding on the 3rd postoperative day. Ninety-three percent of patients experienced improvement in neurological symptoms after the procedure. CONCLUSIONS The endonasal endoscopie approach is effective for the treatment of neural compression caused by CVJ pathology. It offers advantages such as lower rates of postoperative dysphagia and respiratory complications when compared with the more traditional transoral approach. However, these 2 approaches should be seen as complementary rather than alternatives. Patient-related factors as well as the surgeons expertise must be considered when making treatment decisions.

Asymptomatic carotid artery stenosis: time to rethink our therapeutic options?

Asymptomatic carotid artery stenosis is a well-recognized risk factor for ischemic stroke, and its prevalence increases with age. In the late 1980s and in the 1990s, well-designed randomized trials established a definite advantage for carotid endarterectomy in reducing the risk of ipsilateral stroke when compared with medical therapy alone. However, medical treatment of cardiovascular disease has improved significantly over the past 2 decades, and this has, in turn, resulted in a decline of the stroke risk in patients with asymptomatic carotid artery stenosis treated medically. This improvement in medical therapy casts doubts on the effectiveness of large-scale invasive treatment in patients with asymptomatic carotid artery stenosis. Several studies have been conducted to identify possible subgroups of patients with asymptomatic stenosis who are at higher risk of stroke in order to maximize the potential benefits of invasive treatment. Ongoing large-scale trials comparing best current medical therapy to available invasive treatments, such as carotid endarterectomy and carotid artery stenting, are likely to shed some light on this debated topic in the near future. In this review, the authors summarize the current controversy surrounding the ideal management of asymptomatic carotid artery stenosis.

Craniotomy for anterior cranial fossa meningiomas: Historical overview

The surgical treatment of meningiomas located at the base of the anterior cranial fossa is often challenging, and the evolution of the surgical strategy to resect these tumors parallels the development of craniotomy, and neurosurgery in general, over the past century. Early successful operations to treat these tumors were pioneered by prominent figures such as Sir William Macewen and Francesco Durante. Following these early reports, Harvey Cushing made significant contributions, allowing a better understanding and treatment of meningiomas in general, but particularly those involving the anterior cranial base. Initially, large-sized unilateral or bilateral craniotomies were necessary to approach these deep-seated lesions. Technical advances such as the introduction of electrosurgery, the operating microscope, and refined microsurgical instruments allowed neurosurgeons to perform less invasive surgical procedures with better results. Today, a wide variety of surgical strategies, including endoscopic surgery and radiosurgery, are used to treat these tumors. In this review, the authors trace the evolution of craniotomy for anterior cranial fossa meningiomas.

Low frequency of delayed ischemic events on MRI after flow diversion for intracranial aneurysms.

BACKGROUND The rate of silent ischemia detected on Magnetic Resonance Imaging (MRI) in the long-term follow-up period following endovascular treatment of intracranial aneurysms with the Pipeline Embolization Device (PED) is not well established. The purpose of this study was to evaluate the occurrence rate of silent ischemia detected on MRI in patients undergoing treatment of intracranial aneurysms with PED receiving at least 6 months of MRI follow-up. METHODS We evaluated our institutions database of patients receiving PED treatment of intracranial aneurysms. Imaging records were searched to identify which patients received an MRI at least six-months postoperatively. MR images were reviewed for evidence of new infarction and medical records were reviewed to determine the clinical outcome. RESULTS Of the 68 patients with MR imaging following aneurysm treatment with PED, 40 patients had an MRI at least six months following treatment with the PED. Of patients with MRI at ≥6 months following PED treatment, 2/40 (5.0%) had a new infarct. Of these, one had a lacunar infarct which was likely non-embolic and one patient had a punctate infarction in the contralateral centrum semiovale. None of these infarcts were symptomatic. CONCLUSIONS In this study, a small number of silent ischemic events (5.0%) was found on routine long-term follow-up MRI of patients undergoing flow diversion. These events did not lead to any neurologic deficits. Our findings add to the available evidence on the long-term safety of flow diversion for the treatment of intracranial aneurysms.

Resection of spinal hemangioblastoma

Spinal cord hemangioblastomas occur as sporadic lesions or in the setting of Von Hippel-Lindau disease. In this intraoperative video we present a case of sporadic cervical cord hemangioblastoma and illustrate the main surgical steps to achieve safe and complete resection which include: identification and division of the feeding arteries; careful circumferential dissection of the tumor from the surrounding gliotic cord; identification, isolation and division of the main venous drainage and single piece removal of the tumor. The video can be found here: http://youtu.be/I7DxqRrfTxc.

Resection of cervical ependymoma.

Intramedullary ependymomas are surgically curable tumors. However, their surgical resection poses several challenges. In this intraoperative video we illustrate the main steps for the surgical resection of a cervical intramedullary ependymoma. These critical steps include: adequate exposure of the entire length of the tumor; use of the intraoperative ultrasound; identification of the posterior median sulcus and separation of the posterior columns; Identification of the plane between the spinal cord and the tumor; mobilization and debulking of the tumor and disconnection of the vascular supply (usually from small anterior spinal artery branches). Following these basic steps a complete resection can be safely achieved in many cases. The video can be found here: http://youtu.be/QMYXC_F4O4U.

Aberrant direct origin of the cerebellar arteries from the internal carotid artery

The persistence of carotid-basilar anastomoses is a well known but rare condition, with the trigeminal artery being the most common. Cerebellar arteries originating directly from the internal carotid artery are considered variants of the persistent trigeminal artery and are less known. The authors present 3 cases of anomalous origin of the cerebellar arteries from the internal carotid artery and a review of the literature to elucidate their etiology and clinical implications. Although these anatomic variants are often an incidental finding, their recognition is important to explain atypical clinical presentations and for preoperative planning of surgical and endovascular procedures.