Andrew Conger

Diagnosis and evaluation of intracranial arteriovenous malformations

Background: Ideal management of intracranial arteriovenous malformations (AVMs) remains poorly defined. Decisions regarding management of AVMs are based on the expected natural history of the lesion and risk prediction for peritreatment morbidity. Microsurgical resection, stereotactic radiosurgery, and endovascular embolization alone or in combination are all viable treatment options, each with different risks. The authors attempt to clarify the existing literatures understanding of the natural history of intracranial AVMs, and risk-assessment grading scales for each of the three treatment modalities. Methods: The authors conducted a literature review of the existing AVM natural history studies and studies that clarify the utility of existing grading scales available for the assessment of peritreatment risk for all three treatment modalities. Results: The authors systematically outline the diagnosis and evaluation of patients with intracranial AVMs and clarify estimation of the expected natural history and predicted risk of treatment for intracranial AVMs. Conclusion: AVMs are a heterogenous pathology with three different options for treatment. Accurate assessment of risk of observation and risk of treatment is essential for achieving the best outcome for each patient.

Endovascular and microsurgical treatment of cerebral arteriovenous malformations: Current recommendations

Background: Cerebral arteriovenous malformations (AVMs) can be a heterogeneous pathological entity whose management requires a complex decision-making process due to the risks associated with their treatment and natural history. Despite the recently published conclusions of the aborted Randomized Trial of Brain Unruptured AVMs (ARUBA) trial, the authors of this article believe multimodality intervention in general and microsurgical resection in particular continue to play a major role in the management of carefully selected ruptured or unruptured AVMs. Methods: The authors provide an overview of their methodology for endovascular intervention and microsurgical resection and share their technical nuances for successful embolization and microsurgical resection of AVMs with special emphasis on complication avoidance. Results: The authors have achieved successful outcomes in embolization and resection of cerebral AVMs when using their methodology. Conclusions: These lesions are among the most technically difficult pathological entities handled by the cerebrovascular specialist, and an overview of technical concepts to help systematize this challenging and variable endeavor can improve the safety of their treatment.

Resection of Dominant Insular Low-Grade Gliomas: Microsurgical Techniques and Mapping Strategies: Operative 3-Dimensional Video

Resection of dominant-side insular gliomas poses challenges due to the involvement or close proximity of eloquent cortex, the basal ganglia, and middle cerebral artery branches and perforators. The degree of surgical resection of low-grade gliomas is positively correlated with outcome. Therefore, the goal of surgery is maximal tumor resection along with preservation of the patient’s neurological function. Intraoperative stimulation mapping of the associated eloquent cortices during an awake craniotomy, along with neuronavigation and microsurgical techniques, safely facilitates maximal tumor resection. The authors, using the accompanying 3-dimensional video, demonstrate their preferred techniques for intraoperative stimulation mapping and microsurgical resection of a dominant insular low-grade glioma. The patient is a 32-year-old woman who underwent resection of a recurrent left frontotemporal and insular WHO grade II oligoastrocytoma. Surveillance magnetic resonance imaging demonstrated recurrent tumor approximately 4 years after her initial resection. Motor function of her face and tongue as well as expressive and receptive language function were mapped at 6 mA under awake conditions using electrocorticography to assess for afterdischarges. An anterotemporal lobectomy was then performed, including the superior temporal gyrus, because no language function was localized there. This expanded the operative corridor to the insula, and the remainder of the tumor was removed underneath frontal operculae using microsurgical techniques and subcortical mapping at 8 mA. A nearly gross total resection was achieved, and the patient recovered from surgery without any complications. The 3-D video can be viewed at http://bit. ly/1kjXcWJ or to view the video on a mobile device, scan this QR Code to link to an anaglyph (red/green) version of this 3-D video.