Radiation-Induced Imaging Changes and Cerebral Edema following Stereotactic Radiosurgery for Brain AVMs.

BACKGROUND AND PURPOSE: T2 signal and FLAIR changes in patients undergoing stereotactic radiosurgery for brain AVMs may occur posttreatment and could result in adverse radiation effects. We aimed to evaluate outcomes in patients with these imaging changes, the frequency and degree of this response, and factors associated with it. MATERIALS AND METHODS: Through this retrospective cohort study, consecutive patients treated with stereotactic radiosurgery for brain AVMs who had at least 1 year of follow-up MR imaging were identified. Logistic regression analysis was used to evaluate predictors of outcomes. RESULTS: One-hundred-sixty AVMs were treated in 148 patients (mean, 35.6 years of age), including 42 (26.2%) pediatric AVMs. The mean MR imaging follow-up was 56.5 months. The median Spetzler-Martin grade was III. The mean maximal AVM diameter was 2.8 cm, and the mean AVM target volume was 7.4 mL. The median radiation dose was 16.5 Gy. New T2 signal and FLAIR hyperintensity were noted in 40% of AVMs. T2 FLAIR volumes at 3, 6, 12, 18, and 24 months were, respectively, 4.04, 55.47, 56.42, 48.06, and 29.38 mL Radiation-induced neurologic symptoms were encountered in 34.4%. In patients with radiation-induced imaging changes, 69.2% had new neurologic symptoms versus 9.5% of patients with no imaging changes (P = .0001). Imaging changes were significantly associated with new neurologic findings (P < .001). Larger AVM maximal diameter (P = .04) and the presence of multiple feeding arteries (P = .01) were associated with radiation-induced imaging changes. CONCLUSIONS: Radiation-induced imaging changes are common following linear particle accelerator-based stereotactic radiosurgery for brain AVMs, appear to peak at 12 months, and are significantly associated with new neurologic findings.

Spinal dural arteriovenous fistulas: clinical experience with endovascular treatment as a primary therapy at 2 academic referral centers.

BACKGROUND AND PURPOSE: Spinal dural arteriovenous fistulas are a rare entity that, if left untreated, can lead to considerable morbidity with progressive spinal cord symptoms. The aim of this study was to evaluate the clinical outcome of patients with spinal dural arteriovenous fistulas that were primarily treated with endovascular embolization. MATERIALS AND METHODS: A retrospective review was performed of all patients from 1997-2010 who underwent treatment at 2 academic referral centers for a spinal dural arteriovenous fistula. Follow-up was performed by clinical examination, and functional status was measured by use of the Aminoff-Logue Disability Scale, McCormick classification grading, and mRS scores. The nonparametric Wilcoxon signed rank test was used to compare pretreatment and posttreatment Aminoff-Logue Disability Scale gait and micturition scores, McCormick classification grading, and mRS scores. P values < .05 were considered significant. RESULTS: A total of 38 patients were included. Five patients (2 endovascular, 3 surgical) were lost to follow-up and therefore were excluded from the analysis, 29 patients were initially treated from an endovascular approach (9 Onyx, 20 cyanoacrylate), and 4 patients were treated from a standard surgical approach. Five patients in the endovascular group subsequently underwent surgery for various reasons. The clinical improvements in the Aminoff-Logue Disability Scale gait and micturition scores, McCormick classification grading, and the mRS scores were statistically significant (P < .05, Wilcoxon signed rank test). CONCLUSIONS: We conclude that endovascular treatment of spinal dural arteriovenous fistulas can result in good clinical outcomes. Surgery remains the treatment of choice when safe embolization of the proximal radicular draining vein cannot be obtained or because the shunting artery of the spinal dural arteriovenous fistula also supplies the anterior spinal, posterior spinal, or a radiculomedullary artery.

Fatal progression of posttraumatic dural arteriovenous fistulas refractory to multimodal therapy. Case report.

The authors report the case of a man who suffered from progressive, disseminated posttraumatic dural arteriovenous fistulas (DAVFs) resulting in death, despite aggressive endovascular, surgical, and radiosurgical treatment. This 31-year-old man was struck on the head while playing basketball. Two weeks later a soft, pulsatile mass developed at his vertex, and the man began to experience pulsatile tinnitus and progressive headaches. Magnetic resonance imaging and subsequent angiography revealed multiple AVFs in the scalp, calvaria, and dura, with drainage into the superior sagittal sinus. The patient was treated initially with transarterial embolization in five stages, followed by vertex craniotomy and surgical resection of the AVFs. However, multiple additional DAVFs developed over the bilateral convexities, the falx, and the tentorium. Subsequent treatment entailed 15 stages of transarterial embolization; seven stages of transvenous embolization, including complete occlusion of the sagittal sinus and partial occlusion of the straight sinus; three stages of stereotactic radiosurgery; and a second craniotomy with aggressive disconnection of the DAVFs. Unfortunately, the fistulas continued to progress, resulting in diffuse venous hypertension, multiple intracerebral hemorrhages in both hemispheres, and, ultimately, death nearly 5 years after the initial trauma. Endovascular, surgical, and radiosurgical treatments are successful in curing most patients with DAVFs. The failure of multimodal therapy and the fulminant progression and disseminated nature of this patient's disease are unique.

Cerebrovascular manifestations in 321 cases of hereditary hemorrhagic telangiectasia.

BACKGROUND AND PURPOSE: Patients with hereditary hemorrhagic telangiectasia (HHT) are at risk for developing cerebral vascular malformations and pulmonary arteriovenous fistulae. We assessed the risk of neurological dysfunction from these malformations and fistulae. METHODS: Three hundred twenty-one consecutive patients with HHT seen at a single institution over a 20-year period were studied. Any evidence of prior neurological symptoms or presence of an intracranial vascular malformation was recorded. All cases of possible cerebral arteriovenous malformation were confirmed by conventional arteriography. RESULTS: Twelve patients (3.7%) had a history of cerebral vascular malformations. Ten patients had arteriovenous malformations, 1 had a dural arteriovenous fistula, and 1 had a cavernous malformation. Seven patients (2.1%) presented with intracranial hemorrhage, 2 presented with seizures alone, and 3 were discovered incidentally. The average age at the time of symptomatic intracranial hemorrhage was 25.4 years. All patients with a history of intracranial hemorrhage were classified as Rankin grade I or II at a mean follow-up interval of 6.0 years. A history of cerebral infarction or transient ischemic attack was found in 29.6% of patients with HHT and a pulmonary arteriovenous fistula. CONCLUSIONS: The risk of intracranial hemorrhage is low among people with HHT. Furthermore, a majority of these patients have a good functional outcome after hemorrhage. The data do not suggest a compelling indication for routine screening of patients with HHT for asymptomatic cerebral vascular malformations. By comparison, pulmonary arteriovenous fistulae are a much more frequent cause of neurological symptoms in this population.

Ischemic complications of surgery for anterior choroidal artery aneurysms.

OBJECT: Anterior choroidal artery (AChA) aneurysms account for 4% of all intracranial aneurysms. The surgical approach is similar to that for other supraclinoid carotid artery lesions, but surgery may involve a higher risk of debilitating ischemic complications because of the critical territory supplied by the AChA. METHODS: Between 1968 and 1999, 51 AChA aneurysms in 50 patients were treated using craniotomy and clipping at the Mayo Clinic. There were 22 men (44%) and 28 women (56%) whose average age was 53 years (range 27-79 years). Twenty-four AChA aneurysms (47%) had hemorrhaged; nine patients (18%) had subarachnoid hemorrhage from another aneurysm. Three AChA aneurysms (6%) were associated with symptoms other than rupture. Forty-one patients (82%) achieved a Glasgow Outcome Scale (GOS) score of 4 or 5 at long-term follow up. The surgical mortality rate was 4%, and major surgical morbidity (GOS < or = 3) was 10%. Eight patients (16%) had clinically and computerized tomography-demonstrated AChA territory infarcts. Five of these strokes manifested in a delayed fashion 6 to 36 hours after the operation, and progressed from mild to complete deficit over hours. In 41 patients the aneurysm arose from the internal carotid artery adjacent to the AChA, and in nine patients the aneurysm arose directly from the origin of the AChA itself; four of these nine patients had postoperative infarction. CONCLUSIONS: Surgical treatment of AChA aneurysms involves a significant risk of debilitating ischemic complications. Most postoperative strokes occur in a delayed fashion, offering a potential therapeutic window. Patients with aneurysms arising from the AChA itself have an extremely high risk for postoperative stroke.

Remote cerebellar hemorrhage after supratentorial surgery.

OBJECTIVE: Remote cerebellar hemorrhage (RCH) is an infrequent and poorly understood complication of supratentorial neurosurgical procedures. We retrospectively compared 42 patients who experienced RCH with a case-matched control cohort, to delineate risk factors associated with the occurrence of this complication. METHODS: Between 1988 and 2000, 42 patients experienced RCH after supratentorial neurosurgical procedures at our institution. Diagnoses were made on the basis of postoperative computed tomographic or magnetic resonance imaging findings in all cases. The medical records for these patients were reviewed and compared with those for a control cohort of 43 patients, matched for age, sex, surgical lesion, and type of craniotomy, who were treated during the same period. RESULTS: RCH most commonly occurred after frontotemporal craniotomies for unruptured aneurysm repair or temporal lobectomy and was frequently an incidental finding on postoperative computed tomographic scans. However, some cases of RCH were associated with significant morbidity, and two patients died. Preoperative aspirin use and elevated intraoperative systolic blood pressure were significantly associated with RCH (P = 0.026 and P = 0.036, respectively). Pathological findings for two cases demonstrated hemorrhagic infarctions in both. CONCLUSION: RCH most commonly follows supratentorial neurosurgical procedures, performed with the patient in the supine position, that involve opening of cerebrospinal fluid cisterns or the ventricular system (such as unruptured aneurysm repair or temporal lobectomy). Preoperative aspirin use and moderately elevated intraoperative systolic blood pressure are potentially modifiable risk factors associated with the development of RCH. Although RCH can cause death or major morbidity, most cases are asymptomatic or exhibit a benign course. Cerebellar "sag" as a result of cerebrospinal fluid hypovolemia, causing transient occlusion of superior bridging veins within the posterior fossa and consequent hemorrhagic venous infarction, is the most likely pathophysiological cause of RCH.

Refractory idiopathic intracranial hypertension treated with stereotactically planned ventriculoperitoneal shunt placement.

OBJECT: Ventriculoperitoneal (VP) shunts have not been widely used for idiopathic intracranial hypertension (IIH) because of the difficulty of placing a shunt into normal or small-sized ventricles. The authors report their experience with stereotactic placement of VP shunts for IIH. METHODS: The authors reviewed the clinical records of all patients in whom stereotaxis was used to guide the placement of a VP shunt for IIH at their institution. All shunts were placed using stereotactic guidance to target the frontal horn of the lateral ventricle. Patients were contacted at a mean postoperative interval of 15.1 months. No patients were lost to follow up. The authors identified 13 patients who underwent placement of a stereotactically guided VP shunt for IIH over a 6-year period. A trial of either acetazolamide or steroid therapy had failed in all patients. Prior surgical treatments included optic nerve sheath fenestrations in seven patients and cerebrospinal fluid diversionary procedures, other than stereotactic VP shunt procedures, in nine patients. Twelve patients reported excellent or good durable symptomatic relief at the time of follow up. No patient suffered progression of visual deficits. Four patients experienced persistent headaches following the procedure. Three patients required a revision of the VP shunt for technical failure. CONCLUSIONS: Stereotactically guided VP shunt placement is an effective and durable treatment option in many cases of IIH that are refractory to more traditional medical and surgical approaches.

Radiation induced vascular injury after stereotactic radiosurgery for trigeminal neuralgia: case report.

BACKGROUND: Stereotactic radiosurgery is increasingly used for the treatment of medically unresponsive trigeminal neuralgia. CASE DESCRIPTION: We present the case of a 69-year-old man with trigeminal neuralgia who underwent stereotactic radiosurgery after a failed balloon compression procedure. The radiosurgery also failed to provide the patient with any significant pain relief, and microvascular decompression of the trigeminal nerve was performed 10 months later. At operation, two adjacent veins and the superior cerebellar artery were noted to have focal changes consistent with atheromatous disease. CONCLUSION: We postulate that the recent radiation exposure resulted in the observed vascular injury. As a result, patients having trigeminal neuralgia radiosurgery need to be followed carefully for possible delayed ischemic events secondary to radiation-induced vascular injury.

Early vasculopathy following radiation in a child with medulloblastoma.

A child with severe radiation vasculopathy 15 months following radiation therapy for medulloblastoma is reported. The patient underwent surgical resection of a posterior fossa medulloblastoma, followed by chemotherapy and radiation therapy. He was treated with 55 Gy to the craniospinal axis. Fifteen months later, the patient presented with a subacute neurologic deterioration from multiple ischemic events that resulted from severe radiation vascular injury. We compare and contrast this case to similar case reports in the literature.

Surgical treatment of nonatherosclerotic lesions of the extracranial carotid artery.

Nonatherosclerotic disorders of the extracranial carotid artery, such as dissections, aneurysms, and carotid body tumors, are diverse in their causes, presentations, and modes of treatment. The surgical treatment of these lesions often will require a higher exposure of the extracranial carotid than is typical for a carotid endarterectomy. The prevention of perioperative ischemic injury assumes a major role in determining the surgical strategy for treating these lesions. This article offers a brief description of several of these disorders, a review of the general surgical approach to the high cervical artery, and a brief description of lesion-specific surgical techniques.

Surgical treatment of spontaneous spinal cerebrospinal fluid leaks.

Spontaneous spinal cerebrospinal fluid (CSF) leaks are an increasingly recognized cause of intracranial hypotension. In this report the authors review the indications for surgery, surgical techniques, and surgery-related outcomes for these lesions. The major presenting symptoms include postural headaches, nausea, vomiting, and diplopia. Often, there is no history of traumatic injury. The most common cranial magnetic resonance (MR) imaging features include pachymeningeal gadolinium enhancement and sagging of the brain. On spinal MR images, diverticula are frequently noted. In cases in which symptoms are severe and refractory to less invasive measures, surgical intervention is indicated. Tears in the dura or leaking diverticula that are identified as the sources of the CSF leak often can be ligated or repaired. When a source of CSF egress is not found intraoperatively, packing the epidural space with blood-soaked Gelfoam or muscle at the appropriate level can lead to relief of symptoms. Occasionally the dural defect is large, irregular, or has attenuated borders that may not be possible to repair with sutures. These may be repaired by packing the defect with muscle or blood-soaked Gelfoam. Indications for and outcomes of surgery in patients with this condition will become more defined as surgeons gain experience with these procedures.

Lateral exit-zone stenosis and lumbar radiculopathy.

OBJECT: Hypertrophy of the superior facet of the inferior vertebra, resulting in a compression of the nerve root at the lateral foraminal exit, is a recognized cause of radicular symptoms, particularly in patients in whom previous lumbar spine surgery has failed. The lesion-specific presenting symptoms, imaging findings, and surgical treatment of this lesion, however, have received little attention. The authors prospectively studied a series of eight consecutive patients, in whom a diagnosis of lumbar stenosis at the lateral foraminal exit had been made, to elucidate the common presenting signs and symptoms of this disorder, as well as to evaluate the success of the operative treatment. METHODS: The eight patients were selected from a group of 250 consecutive patients who presented to a tertiary-care hospital and in whom a diagnosis of long-standing lumbar radiculopathy had been made. In all cases the diagnosis was confirmed by imaging studies and by intraoperative findings. The authors performed decompressive procedures on the nerve root via a medial facet-sparing approach. CONCLUSIONS: The authors conclude that this lesion presents with characteristic physical findings and on imaging studies that distinguish it from other causes of radiculopathy, and they propose a lesion-specific, facet-sparing surgical technique that has yielded excellent results.