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Preoperative, Intraoperative, and Postoperative Imaging

Pearls Wada testing was originally developed to anticipate postoperative surgical deficit. Test characteristics vary based on agent used, anatomic location of the AVM, and clinical situation. The advent of microcatheter techniques has encouraged the use of superselective Wada testing. It may be less successful in predicting complication profiles with embolization than with surgery. Intraoperative and postoperative digital subtraction angiography remain the mainstay gold standard for the…

Obstetric Considerations in AVM Management

Pearls Epidemiological data regarding iAVM rupture risk in pregnancy is equivocal and underpowered in the literature, and reports of peripartum iAVM rupture are rare. Physiological considerations in iAVM management include cardiac output, blood coagulability, systemic vascular resistance, and fetal gestational age. Diagnostic studies should limit fetal exposure to contrast agents and radiation. MRI should be preferentially used and CT or angiography reserved for critical diagnostic detail…

Intracranial AVMs and the Neurointensivist

Acknowledgment The authors would like to thank Ms. Kelsey Lansdale for her assistance with the illustrations. Pearls Intracranial hemorrhage and subsequent seizures, headaches, and focal neurological deficits are common presentations in patients with symptomatic iAVMs. Multidisciplinary care of patients with iAVMs in the neurointensive care unit is warranted, particularly for those with hemorrhage and for patients undergoing surgical and/or endovascular interventions. The preoperative management in cases…

Management of Perioperative Complications During AVM Treatment

Pearls Sudden and sustained blood loss remains an important perioperative concern in iAVM procedures and requires anticipatory management. Malignant cerebral edema and intracranial hypertension may be refractory to medical management following iAVM treatment. Clinical and subclinical seizures require vigilance in both diagnosis and management. The perioperative period requires tight hemodynamic management control, close surveillance of the neurologic exam, and timely use of imaging to treat potential…

Anesthetic Management of Intracranial AVMs

Pearls Hemodynamic stability is paramount during iAVM intervention and predicated upon euvolemia and adequate anesthesia depth. Brain relaxation and surgical field optimization facilitates resection (see Table 25.1 ). No anesthetic agent or hypothermia has been shown to be superior in neuroprotection during surgery. Tight hemodynamic control and smooth emergence are anesthetic goals intended to reduce the risk for acute postoperative complications. Use of intraoperative neurophysiologic monitoring…

Medical Comorbidities in Elective Surgery

Pearls Comorbidities have not been found to be predictive in iAVM treatment outcomes. Any patient with a medical comorbidity should be evaluated by the appropriate specialist. Patients who have seizures related to their iAVM benefit from resection. Liver disease is associated with worse neurosurgical outcomes in general. Treatment should be maximized prior to any invasive interventions. Management of headache associated with iAVMs should be guided by…

Emergency Management of Ruptured Intracranial AVMs

Pearls Acute management of ruptured iAVMs is driven by supportive care required for the intraparenchymal hemorrhage. Medical management focuses on seizure prophylaxis, blood pressure control, and intracranial pressure control. Structural imaging (CTA/MRA) and cerebral angiography can identify high-risk features and define the angioarchitecture of the iAVM. Delayed treatment with surgery 4–6 weeks after the hemorrhage event may bring technical advantages to surgery. The interval acute rerupture…

Risks of Radiosurgery

Pearls The risk for iAVM hemorrhage is uncertain during the latency period of SRS (i.e., time to obliteration ~ 2 years). Acute radiation effects are rare; headaches and seizures are easily treated. Early delayed effects of SRS (radiation-induced imaging changes) are usually transient and medically managed. Late delayed effects from SRS include radiation necrosis, cyst formation, and encapsulated hematomas. The risk of radiation-induced neoplasms from SRS…

Risks of Combined Therapies

Pearls Each individual technique for treating AVMs has its own risk profile, and while often overlapping, there are some differences. Surgery carries a risk of infection relating to the craniotomy, retraction injury, cerebral contusion, hemorrhage, seizure, and so on. Radiosurgery also carries a risk of hemorrhage, which can necessitate a craniotomy; while effective, it carries a unique risk of radiation necrosis, injury, and vasculopathy. Embolization has…

Risks of Endovascular Treatment of AVMs

Acknowledgments We thank the staff of Neuroscience Publications at Barrow Neurological Institute for assistance with manuscript preparation. Pearls Intracranial AVMs can be embolized for five different strategies: curative intent, preoperative, preradiosurgical, targeted, or palliative. The most common indication is preoperative embolization, and the relative goals of each aspect of this treatment combination should be balanced to reduce the risk to the patient at each stage. Risks…

Grading Systems and Surgical Risks

Pearls Surgical risk at experienced centers can be accurately determined. Preoperative use of functional MRI, diffusion tensor imaging, and Wada testing along with routine MRI, CT angiography, and digital subtraction angiography greatly facilitates interventional risk assessment. Location, size, venous drainage, perforating vessels, and diffuseness are key to surgical risk assessment in association with age, medical comorbidities, and acuteness in surgical episode. Multimodality therapy is often employed,…

Conservative Management (“Observation”) of Intracranial AVMs

Pearls The annual bleeding risk from unruptured/asymptomatic iAVMs is 2%–3%. Intervention, usually surgery, is recommended for small iAVMs in noneloquent areas. Observation is often recommended for large iAVMs in eloquent areas. Age, projected duration of risk, and associated aneurysms are important in treatment choice. Careful evaluation of natural history vs treatment risk is essential when considering observation. Introduction Current management of intracranial arteriovenous malformations (iAVMs) includes…

Palliation Versus Observation: Nonresectable AVMs

Pearls Palliation is reserved for symptomatic iAVMs deemed untreatable with surgery. Palliation includes partial embolization or staged stereotactic radiosurgery. The goal of palliation is to alleviate ischemic symptoms, headache, or seizures in patients with noncurable iAVMs. New innovative transvenous embolization techniques may increase the number of iAVMs that are potentially curable. Observation is a very reasonable option for high-risk iAVMs. Defining Nonresectable iAVMs Defining nonresectable intracranial…

Multimodal/Combined Therapy: Goals and Outcomes

Pearls The risk of hemorrhage dictates neurosurgical intervention for iAVMs. Stereotactic radiosurgery (SRS) is utilized when microsurgical resection of an iAVM is not possible due to location, size, feeding vessels, or medical comorbidities that preclude resective surgery. Embolization is often used as an adjuvant therapy to radiosurgery and microsurgical resection, although in selected cases it can be used as a primary method of iAVM nidus obliteration.…

Principles of Neuroendovascular Management of AVMs: Goals, Timing, Techniques, and Outcomes

Acknowledgments We thank Paul H. Dressel BFA for research assistance on the illustrations and Debra J. Zimmer for editorial assistance. Pearls Endovascular techniques are practiced in four different settings in the treatment of iAVMs, each with an associated goal: adjunctive (preoperative embolization to facilitate microsurgical resection or radiosurgery), curative (embolization attempted for cure), targeted therapy (to treat the source of bleeding), and palliative (embolization to reduce…

Radiosurgery Principles for AVM Management: Techniques, Goals, and Outcomes

Disclosure Dr. Lunsford is a stockholder of AB Elekta and DSMB chair for Insightec, Inc. Pearls Stereotactic radiosurgery has become the most frequently used option for the treatment of iAVMs. The goal is AVM obliteration, which is related to AVM volume and radiation dose delivered. The best outcomes (obliteration with high-quality neurological outcome) are achieved in 55%–85% of patients over intervals of 1–3 years. Embolization before…

Surgical Principles: Techniques, Goals, and Outcomes

Pearls Definitive treatment is only achieved with complete obliteration or excision of the iAVM. In cases of ruptured iAVMs, surgery is usually delayed several weeks if the patient is neurologically stable. The surgical goal must be complete iAVM resection, taking all risk factors into consideration preoperatively. All feeding vessels to the iAVM mass (nidus) are taken “before” the draining vein. Surgery is best performed in high-volume…

Decision Analysis for AVM-Associated Aneurysms

Pearls Aneurysms associated with iAVMs constitute a heterogeneous group with different risk profiles that must be taken into account when considering management options. In cases of hemorrhagic presentation, determining the source of hemorrhage (i.e., aneurysm vs iAVM) is crucial. Distal flow-related aneurysms and intranidal aneurysms increase the risk of hemorrhagic presentation. Curability of the iAVM and accessibility and proximity of the aneurysm to the iAVM are…

Decision Analysis for Symptomatic Lesions

Pearls Patients with iAVMs typically present after hemorrhage, seizure, or the appearance of focal neurologic deficits. Comprehensive evaluation includes CT, MRI, MR angiography, CT angiography, and digital subtraction angiography, with additional studies as required and based on location. If possible, surgery after rupture is usually delayed to allow for resolution of edema and swelling and for accurate nidus identification. Treatment of symptomatic lesions often involves multiple…

Decision Analysis for Asymptomatic Lesions

Pearls Asymptomatic iAVMs carry an ~ 2.2% annual risk for hemorrhage. If followed, asymptomatic AVMs that rupture carry a minimum 40% morbidity Genetic and environmental factors play a role in iAVM development. Risk factors for hemorrhage include intranidal or venous aneurysms, deep location, deep venous drainage, and infratentorial location. Multimodal therapy, including observation, radiosurgery, embolization, and microsurgery, must be balanced with hemorrhage risk, age, iAVM location,…