Vascular complications of stereotactic radiosurgery for arteriovenous malformations

Multiple Intracranial Aneurysms Associated With Brain Arteriovenous Malformation: A Case Report and Treatment Strategies

In the field of cerebrovascular neurosurgery, intracranial aneurysms (IAs) have been occasionally associated with brain arteriovenous malformations (BAVMs), indicating a more aggressive clinical course, and increased rates of hemorrhage and rehemorrhage. Treatment of flow-related IAs in BAVMs remains debatable, with considerations for preventive intervention versus concurrent BAVM treatment. Managing such situations might be challenging, especially in determining which of the IAs or BAVMs should be treated first, and which treatment strategy would be most appropriate for each situation. A precise identification of the rupture site is required, whether it is the AVM nidus or the IA, for choosing the best treatment plans. We present a case of a 29-year-old male patient diagnosed with several intracranial vascular conditions: a ruptured anterior communicating artery (ACoA) aneurysm and an unruptured ophthalmic artery aneurysm, associated with a frontal BAVM. Moreover, we discussed the possible scenarios regarding the association of these conditions, highlighting their manifestations and the most suitable therapeutic approach for each. Thus, our exploration of the challenges and considerations involved in treating these intricate neurovascular conditions underscores the need for a customized approach for each patient's situation.

Formation of internal carotid artery aneurysms following gamma knife radiosurgery for pituitary adenomas: a case series and literature review

Only two aneurysm formations in the internal carotid artery after gamma knife radiosurgery (GKRS) for pituitary adenomas are reported so far. Here, out of the 482 patients who underwent GKRS for pituitary adenomas at our institute, at least five developed aneurysms within the area of high single-dose irradiation. Three patients presented with epistaxis due to aneurysmal rupture and one presented with abducens paralysis due to nerve compression, while one was asymptomatic. The interval between irradiation and aneurysmal detection ranged from 14 to 21 years. Aneurysm formation in those conditions may be higher than previously thought.

Clinical outcome following cerebral AVM hemorrhage

BACKGROUND

A significant difference exists between the published results reporting the clinical outcome following brain arteriovenous malformation (AVM) ruptures. Information about the outcome following hemorrhage in an AVM population treated with radiosurgery could provide additional information to assess the risk of mortality and morbidity following an AVM hemorrhage.

METHODS

Clinical outcome was studied in 383 patients, the largest patient population yet studied, who suffered from a symptomatic hemorrhage after Gamma Knife® surgery (GKS) but before confirmed AVM obliteration. The impact of different patient, AVM, and treatment parameters on the clinical outcome was analyzed. The aim was to generate outcome predictions by comparing our data to and combining them with earlier published results.

RESULTS

No relation was found between clinical outcome and treatment parameters, indicating that the results are applicable also on untreated AVMs. Twenty-one percent of the patients died, 45% developed or experienced worsening of neurological sequelae, and 35% recovered completely after the hemorrhage. Old age was a predictor of poor outcome. Sex, AVM location, AVM volume, and history of prior hemorrhage did not influence the outcome. The mortality rate was comparable to earlier published prospective data, but higher than that found in retrospective studies.

CONCLUSIONS

The mortality rates in earlier published retrospective series as well as in studies focusing on clinical outcome following AVM hemorrhage significantly underestimate the risk for a mortal outcome following an AVM hemorrhage. Based on our findings, an AVM rupture has around 20% likelihood to result in mortality, 45% likelihood to result in a minor or major deficit, and 35% likelihood of complete recovery. The findings are probably applicable also for AVM ruptures in general. The cumulative mortality and morbidity rates 25 years after diagnosis were estimated to be around 40% in a patient with a patent AVM.

Outcome Comparison Between Surgically Treated Brain Arteriovenous Malformation Hemorrhage and Spontaneous Intracerebral Hemorrhage

BACKGROUND

Case fatality and poor outcome rates are different between brain arteriovenous malformation-associated intracerebral hemorrhage (bAVM-ICH) and spontaneous intracerebral hemorrhage (SICH). These outcome rates, however, have never been compared in patients who need neurosurgical evacuation of the intracerebral hemorrhage (ICH).

OBJECTIVE

To compare the short- and long-term functional outcome between surgically treated patients with bAVM-ICH and SICH.

METHODS

We collected data from surgically treated ICH patients at the Department of Neurosurgery, University Hospital Zurich, from January 2015 to July 2018. We performed logistic regression analysis to compare the functional outcome between groups, adjusting for demographics, admission characteristics, and stroke risk factors.

RESULTS

A total of 26 bAVM-ICH and 115 SICH patients were included in the final analysis. Patients with bAVM-ICH were younger and less likely to have hypertension without significant differences in ICH volume, hematoma location, intraventricular hemorrhage, and other stroke risk factors. A significantly better functional outcome rate was seen in bAVM-ICH patients at short- and long-term follow-up. These differences remained significant after adjusting for confounders.

CONCLUSIONS

patients with a bAVM who need surgical evacuation of an ICH have a more favorable outcome than surgically treated patients with spontaneous ICH, even after correction for confounding factors, such as younger age and less premorbid hypertension.

Refractory De Novo Multiple Cerebral Aneurysms After Radiotherapy and Multistaged "Open" Surgical Treatment for Low-Grade Glioma During Long-Term Follow-Up: A Case Report and Review of the Literature

Background

Radiation-induced aneurysms have been previously reported; however, multiple and repeated de novo aneurysm formation chronologically and anatomically during long-term follow-up have not yet been observed. The pathogenesis of persistent radiation-induced vasculopathy is not fully understood.

Case Description

A 31-year-old woman presented with intraventricular hemorrhage due to rupture of a right internal carotid artery (ICA) aneurysm that developed 17 years after surgical resection of a low-grade glioma in the right frontal lobe and postoperative radiotherapy (focal, 50 Gy/25 fractions). During glioma follow-up, salvage surgery with adjuvant gamma knife therapy and chemotherapy (ranimustine, vincristine, temozolomide) were performed for recurrence of the glioma. The aneurysm was treated with endovascular coil embolization. However, she experienced repeated intraventricular hemorrhages, and angiography revealed a de novo ICA aneurysm. The de novo aneurysms were treated with endovascular surgery using coil embolization and stenting. At 2 years after the third hemorrhage, the surgical wound became dehiscent, probably due to wound infection, thus epicranial soft tissue reconstruction using vascularized skin flap was performed. Despite multistaged endovascular surgery for the ICA aneurysm, she experienced repeated subarachnoid and intraventricular hemorrhages. Angiography revealed a de novo aneurysm of the right posterior cerebral artery and basilar trunk. She underwent coil embolization and stenting. Despite active management with endovascular surgery and close follow-up, she died after an eighth consecutive intraventricular and intracerebral hemorrhage caused by a de novo large aneurysm of the posterior cerebral artery.

Conclusions

To the best of our knowledge, the present study is the first to report on of refractory and recurring de novo aneurysms treated by multistaged endovascular surgery during a long-term follow-up after radiotherapy and multistaged craniotomy for glioma.

Internal carotid artery aneurysms diagnosed after stereotactic radiosurgery for a growth hormone-secreting pituitary adenoma: a case report and literature review

Radiation therapy is associated with the subsequent development of cerebral aneurysms; however, stereotactic radiosurgery (SRS)-associated aneurysm cases have not been well documented, with only 18 cases reported to date. We present a case of intracranial aneurysms with the rupture occurring 20 years after SRS for a growth hormone-producing pituitary adenoma. This is the first report of aneurysms diagnosed following transsphenoidal surgery and SRS for pituitary adenoma. We believe that the aneurysm reported here is a consequence of the SRS treatment, and thus this may be a very rare long-term complication following radiation treatments.

A study of pediatric cerebral arteriovenous malformations: clinical presentation, radiological features, and long-term functional and educational outcomes with predictors of sustained neurological deficits

OBJECTIVE

Large experiences with the treatment of pediatric arteriovenous malformations (AVMs) remain relatively rare, with limited data on presentation, treatment, and long-term functional outcomes. Because of the expected long lifespan of children, caregivers are especially interested in outcome measures that assess quality of life. The authors' intention was to describe the long-term functional outcomes of pediatric patients who undergo AVM surgery and to identify predictors of sustained neurological deficits.

METHODS

The authors analyzed a 21-year retrospective cohort of pediatric patients with intracranial AVMs treated with microsurgery at two institutions. The primary outcome was a persistent neurological deficit at last follow-up. Secondary outcome measures included modified Rankin Scale (mRS) score and independent living.

RESULTS

Overall, 97 patients (mean age 11.1 ± 4.5 years; 56% female) were treated surgically for intracranial AVMs (mean follow-up 77.5 months). Sixty-four patients (66%) presented with hemorrhage, and 45 patients (46%) had neurological deficits at presentation. Radiologically, 39% of lesions were Spetzler-Martin grade II. Thirty-seven patients (38%) with persistent neurological deficits at last follow-up were compared with those without deficits; there were no differences in patient age, presenting Glasgow Coma Scale score, AVM size, surgical blood loss, or duration of follow-up. Multivariate analysis demonstrated that a focal neurological deficit on presentation, AVM size > 3 cm, and lesions in eloquent cortex were independent predictors of persistent neurological deficits at long-term follow-up. Overall, 92% of the children had an mRS score ≤ 2 on long-term follow-up.

CONCLUSIONS

Pediatric patients with AVMs treated with microsurgical resection have good functional and radiological outcomes. There is a high rate (38%) of persistent neurological deficits, which were independently predicted by preoperative deficits, AVMs > 3 cm, and lesions located in eloquent cortex. This information can be useful in counseling families on the likelihood of long-term neurological deficits after cerebral AVM surgery.

Subarachnoid Hemorrhage Due to Flow-Related Dissection of the Posterior-Inferior Cerebellar Artery Associated with a Distal Arteriovenous Malformation

BACKGROUND

Cerebral arteriovenous malformations (CAVMs) are characterized by altered hemodynamics and associated with angioanatomic changes, such as aneurysms. We encountered a patient with a CAVM-associated dissection of the medial trunk of the posterior inferior cerebellar artery (PICA) instead of an aneurysm.

CASE DESCRIPTION

We report the case of a 56-year-old male patient with spontaneous subarachnoid hemorrhage within the cisterna magna and fourth ventricle. Digital subtraction angiography revealed a cerebellar arteriovenous malformation located within the inferior semilunar lobule that did not anatomically match the bleeding pattern. The left PICA, serving as a primary feeding artery, showed a dissection of the proximal portion of the medial trunk with a precise anatomic association with the blood in the telovelotonsillar space. CAVM-induced hyperdynamic flow through the feeding vessel is the most plausible pathophysiologic explanation for the dissection. Complete microsurgical resection of the CAVM was performed, and 3-month follow-up digital subtraction angiography showed complete regression of the dissection, disappearance of irregularities, and significant caliber reduction of the medial PICA trunk.

CONCLUSIONS

This is the first report of a hyperdynamic flow-related dissection of a CAVM-associated feeding vessel. Microsurgical resection of the CAVM allowed for spontaneous resolution of the dissected area by restoration of normal rheodynamics.

Long-term follow up data on difficult to treat intracranial arteriovenous malformations treated with the CyberKnife

INTRODUCTION

The CyberKnife, a frameless, robotic, stereotactic device, has been developed to radiosurgically treat arteriovenous malformations (AVMs). While most AVMs are obliterated within two-to-three years, a subset remain recalcitrant; long-term data on these difficult to treat AVMs are limited in the neurosurgical literature.

MATERIALS AND METHODS

A retrospective analysis of all patients who underwent CyberKnife treatment for intracranial AVMs at a single U.S. institution between 2002 and 2012, whose AVMs had failed to obliterate within 48 months or longer from the treatment start date, were eligible for inclusion.

RESULTS

Eleven patients (9 AVMs; 7 males, 2 females) were followed for an average of 85.2 months (range 56.2-119.4). The median lesion size was 3.5 cm (range: 2.8-8.0 cm) and median Spetzler-Martin grade was 3 (range: 2-5). All AVMs were treated with one radiation dose (median prescribed dose was 18.0 Gy; median D_max: 23.7 Gy). Six (66.7%) were obliterated in a median time of 84 months (range: 52-94 months), while 3 (33.3%) remained active after a median of 90.8 months (range 69.7-119.4). Transient, post-radiosurgery adverse radiation effects occurred in 5 (55.6%) cases. One (11.1%) patient had an acute hemorrhage from the AVM after radiosurgery. Four (44.4%) patients underwent repeat radiosurgery and/or embolization. Three of these lesions eventually obliterated, while 1 did not.

CONCLUSION

The median time to obliteration was 84 months. Two-thirds of AVMs which persisted for over 4 years following initial radiosurgery treatment eventually obliterated. Transient post-radiosurgery adverse effects were common; delayed hemorrhages were rare in our case series.

Endovascular glue embolization of a radiation-induced lenticulostriate artery pseudoaneurysm in a pediatric patient with optic pathway glioma: Case report and review of literature

Radiation-associated vascular changes most commonly present in the form of stenosis, thrombosis and occlusion. However, development of intracranial aneurysms secondary to radiation is far less common and often manifests with rupture. These aneurysms are difficult to treat and associated with high morbidity and mortality when ruptured compared with saccular aneurysms unrelated to radiation treatment. Both surgical and endovascular options are available for treatment of these aneurysms. We present a young patient with a radiation-induced intracranial pseudoaneurysm arising from the lenticulostriate branch of the left middle cerebral artery (MCA); this developed 1 year 4 months after 59.4 Gy of focused radiation to the suprasellar pilomyxoid astrocytoma. The patient successfully underwent endovascular glue embolization of the aneurysm and occlusion of the lenticulostriate artery after unsuccessful trapping of the aneurysm and occlusion of the parent artery using coils. She developed transient hemiparesis of the right side following the procedure, which was managed conservatively. We performed a complete review of the literature dealing with the radiation-induced intracranial aneurysms, their presentation, treatment and outcome.

Surgical Management of Adverse Radiation Effects After Gamma Knife Radiosurgery for Cerebral Arteriovenous Malformations: A Population-Based Cohort Study

OBJECTIVE

The goal of this study is to report our experience in the surgical treatment of cerebral arteriovenous malformations (cAVMs) related permanent symptomatic adverse radiation effects (PSAREs), to clarify an appropriate surgical management and to identify the risk factors related to their development.

METHODS

We evaluated 549 patients treated with Gamma Knife radiosurgery (GKRS) for cAVMs with a follow-up of at least 8 years. Univariate and multivariate analyses were used to test different risk factors related to the development of PSARE. We retrospectively reviewed the records of these patients to analyze the clinical outcome.

RESULTS

Fourteen patients (2.5%) developed PSARE and were submitted to surgery. Higher average treated volume represents a significant risk factors for the development of PSARE (P < 0.05); on the other hand, older age and higher average dose reduce the risk of PSARE (P < 0.05). A favorable clinical outcome was achieved in 13 patients (93%) after surgery; in 1 patient, the unfavorable outcome was due to hemorrhage that occurred months after GKRS. Serial MRI scans following either surgical removal of the nodule or Ommaya reservoir positioning showed progressive reduction of brain edema in all cases.

CONCLUSIONS

The management of PSARE is controversial, especially for cAVMs treated with SRS. Surgical removal is rarely needed, but-if unavoidable-it can be a valuable option in experienced hands. A careful preoperative planning is always necessary to detect pathologic blood flow through the PSARE.

Pseudoaneurysm formation and rupture after stereotactic radiotherapy for cerebral arteriovenous malformation: a case report and review of literature

We report a rare delayed complication of de novo pseudoaneurysm formation and rupture after stereotactic radiotherapy for cerebral arteriovenous malformation. The patient presented with intracerebral haemorrhage due to rupture of a pseudoaneurysm in the previously irradiated field, which was excised for histological examination. The literature was reviewed for similar cases.

Angiographic "Blush" After Stereotactic Radiosurgery Ablation of Residual Arteriovenous Malformation in Pediatric Patient: Case Report and Review of Literature

INTRODUCTION

While surgical resection remains a primary treatment for accessible arteriovenous malformations (AVMs), stereotactic radiosurgery (SRS) has become thoroughly integrated into the AVM armamentarium; however, delayed sequelae of this treatment have become evident with increased long-term follow-up. To our knowledge, this is the second case of an aberrant local arterial angiographic blush without early venous drainage or an associated lesion following AVM SRS.

CASE DESCRIPTION

An 8-year-old female presented with a ruptured 4-cm right medial frontal periventricular Spetzler-Martin grade 3 AVM with isolated intraventricular hemorrhage. She underwent subtotal resection followed by SRS. Six years later, diagnostic cerebral angiography demonstrated a prominent arterial-phase filling microvasculature without early venous drainage in the region of the irradiated residual AVM nidus.

CONCLUSION

Although there is a paucity of information on angiographic blush following AVM SRS, consensus in the literature suggests that without early venous drainage, these lesions appear to pose an insignificant threat to the patient. These angiographic findings may be on a spectrum of delayed cerebrovascular radiation changes, and thus indefinite follow-up may be considered, especially in pediatric patients.

Radiotherapy-related intracranial aneurysm: case presentation of a 17-year male and a meta-analysis based on individual patient data

PURPOSE

The aim of this study was to investigate the incidence, clinical profiles, latency, and outcomes of radiotherapy (RT)-related intracranial aneurysms, rare but often fatal complications of cranial irradiation.

METHODS

We reviewed all published individual patient data regardless of language, using survival analysis to make statistical inferences.

RESULTS

We examined a total of 58 patients with RT-related intracranial aneurysms, including one unpublished case presented here, of whom 74.1 % presented with rupture. In the study, 29.3 % were younger than 18 years. The mean age at which patients received the first course of RT was 34.8 ± 22.8 years old. The mean latency between initiating RT and presenting with aneurysm was 10.4 ± 8.5 years. Rapid death ensured in 24 % shortly after presentation. The only significant predictor of death was rupture. In those with a single aneurysm, 43.1 % were located at the internal carotid artery, while 15.5 % of patients had multiple aneurysms. A male-to-female ratio of 1.87, 0.5, and 1.32 was found in patients younger than age 52, 52 years of age or older, and all 58 patients, respectively. Older age when receiving RT and presentation with ruptured aneurysm were significantly associated with shorter latency.

CONCLUSIONS

RT-related intracranial aneurysms presented differently from classical ones based on age, sex, site, multiplicity, and type. Sex ratios differed with age. The younger age group showed a longer latency of occurrence of an aneurysm. Older patients and those who develop ruptured aneurysms presented earlier. Since rupture may affect outcome, early detection of aneurysms before rupture may save lives.

Aneurysms Associated with Brain Arteriovenous Malformations

Brain arteriovenous malformations are frequently associated with the presence of intracranial aneurysms at a higher-than-expected incidence based on the frequency of each lesion individually. The identification of intracranial aneurysms in association with AVMs has increased due to improvement in diagnostic techniques, particularly 3D and superselective conventional angiography. Intracranial aneurysms may confer a higher risk of hemorrhage at presentation and of rehemorrhage in patients with AVMs and therefore may be associated with a more unfavorable natural history. The association of AVMs and intracranial aneurysms poses important therapeutic challenges for practicing neurosurgeons, neurologists, and neurointerventional radiologists. In this report, we review the classification and radiology of AVM-associated intracranial aneurysms and discuss their clinical significance and implications for treatment.

Transvenous Approach to Intracranial Arteriovenous Malformations

A compartmental conceptualization of intracranial arteriovenous malformations (AVMs) allows recognition of feeding arteries, an intervening plexiform nidus, and draining veins. AVM therapy involves eliminating the nidus, which is the source of hemorrhage, without compromising normal arterial and venous drainage of the brain. Traditional methods of AVM therapy through microsurgery and endovascular embolization involve arterial devascularization, with preservation of AVM venous drainage, until the nidus is excluded. The transvenous approach in treating vascular malformations was popularized by successful treatment models for dural arteriovenous fistulas. More recently, high-flow intracranial AVMs are being managed with transvenous endovascular approaches, although this novel technique has its challenges and perils. We review the current literature on transvenous AVM therapy and highlight its role for AVM therapy in the present day.

Radiotherapy and death from cerebrovascular disease in patients with primary brain tumors

Radiotherapy is often used in the management of primary brain tumors, but late cerebrovascular risks remain incompletely characterized. We examined the relationship between radiotherapy and the risk of death from cerebrovascular disease (CVD) in this population. We used the Surveillance, Epidemiology, and End Results Program to identify 19,565 patients of any age diagnosed with a primary brain tumor between 1983-2002. Multivariable competing risks analysis and an interaction model were used to determine whether receipt of radiotherapy was associated with an increased risk of CVD-specific death, adjusting for tumor proximity to central arterial circulations of the brain. The median follow up in surviving patients was 12.75 years. Baseline characteristics were similar in patients who did and did not receive radiotherapy. Ten-year CVD-specific mortality in patients with tumors near central arterial circulations who did and did not receive radiotherapy were 0.64 % (95 % CI 0.42-0.93 %) versus 0.16 % (95 % CI 0.055-0.40 %), p = 0.01. After adjustment for demographic, tumor-related, and treatment-related covariates, patients with tumors near central arterial circulations were significantly more likely to experience CVD-specific mortality after radiotherapy (HR 2.81; 95 % CI 1.25-6.31; p = 0.01); no association was observed among patients with more distant tumors (HR 0.77; 95 % CI 0.50-1.16; p = 0.21). The interaction model showed that tumor location was a key predictor of the risk of radiotherapy-associated, CVD-specific mortality (p-interaction = 0.004). Patients receiving radiotherapy for tumors near but not distant from the central vasculature of the brain are at increased risk for death secondary to CVD, which should be considered when counseling patients.

Delayed Perilesional Ischemic Stroke after Gamma-knife Radiosurgery for Unruptured Deep Arteriovenous Malformation: Two Case Reports of Radiation-induced Small Artery Injury as Possible Cause

Radiation-induced vasculopathy is a rare occurrence, however, it is one of the most serious complications that can occur after gamma-knife radiosurgery (GKRS). The authors present two cases of incidentally found deep cerebral arteriovenous malformation (AVM), which were treated by GKRS, where subsequently there occurred delayed-onset cerebral infarction (11 and 17 months after GKRS) at an area adjacent to the AVM. In both cases, perforators of the M1 segment of the middle cerebral artery were included in the radiation field and delayed injury to these is suggested to be the mechanism of the ischemic event.

Review of cranial radiotherapy-induced vasculopathy

Cranial radiation can impact the cerebral vasculature in many ways, with a wide range of clinical manifestations. The incidence of these late effects including cerebrovascular accidents (CVAs), lacunar lesions, vascular occlusive disease including moyamoya syndrome, vascular malformations, and hemorrhage is not well known. This article reviews the preclinical findings regarding the pathophysiology of late radiation-induced vascular damage, and discusses the clinical incidence and risk factors for each type of vasculopathy. The pathophysiology is complex and dependent on the targeted blood vessels, and upregulation of pro-inflammatory and hypoxia-related genes. The risk factors for adult CVAs are similar to those for patients not exposed to cranial radiotherapy. For children, risks for late vascular complications include young age at radiotherapy, radiotherapy dose, NF1, tumor location, chemotherapy, and endocrine abnormalities. The incidence of late vascular complications of radiotherapy may be impacted by improved technology, therapeutic interventions, and appropriate follow up.

Microsurgical treatment of arteriovenous malformations in pediatric patients: the Boston Children's Hospital experience

OBJECT

Outcomes of microsurgical treatment of arteriovenous malformations (AVMs) in children are infrequently reported across large cohorts.

METHODS

The authors undertook a retrospective review of departmental and hospital databases to obtain the medical data of all patients up to 18 years of age who were diagnosed with cerebral AVMs. Demographic and AVM angioarchitectural characteristics were analyzed, and for the patients who underwent surgery, the authors also analyzed the estimated intraoperative blood loss, postoperative angiographically confirmed obliteration rates, and neurological complications and outcomes classified according to the modified Rankin Scale (mRS).

RESULTS

Of 117 children with cerebral AVMs, 94 underwent microsurgical resection (80%). Twenty (21%) of these 94 patients underwent adjunctive preoperative embolization. The overall postoperative angiographically confirmed obliteration rate was 94%. As part of a new protocol, the last 50 patients in this series underwent immediate perioperative angiography, improving the subsequent obliteration rate from 86% to 100% (p = 0.01). No other factors, such as a hemorrhagic AVM, size of the AVM, location, drainage, or Spetzler-Martin grade, had a statistically significant impact on the obliteration rate. Perioperative neurological deficits occurred in 17% of the patients, but the vast majority of these (77%) were predictable visual field cuts. Arteriovenous malformations that were hemorrhagic or located in noneloquent regions were each associated with lower rates of postoperative neurological complications (p = 0.05 and 0.002, respectively). In total, 94% of the children had good functional outcomes (mRS Scores 0-2), and these outcomes were significantly influenced by the mRS score on presentation before surgery (p = 0.01). A review of 1- and 5-year follow-up data indicated an overall annual hemorrhage rate of 0.3% and a recurrence rate of 0.9%.

CONCLUSIONS

Microsurgical resection of AVMs in children is associated with high rates of angiographically confirmed obliteration and low rates of significant neurological complications. Implementation of a protocol using perioperative angiography in this series led to complete radiographically confirmed obliteration of all AVMs, with low annual repeat hemorrhage and recurrence rates.

Radiation-induced cerebral aneurysm treated with endovascular coil embolization. A case report

Radiation-induced cerebral aneurysms are rare. We describe a case of radiation-induced cerebral aneurysm successfully treated with endovascular coil embolization. A 39-year-old man received 60 Gy of radiation to a pineal germinoma at eight years old. The left internal carotid artery (ICA) aneurysm which developed within the irradiated field and stenotic change in the left ICA due to radiation-induced vasculopathy were detected incidentally. Because these aneurysms show a high risk of rupture and mortality, and even small aneurysms are prone to rupture, any such suspected aneurysm should be treated with surgical or endovascular procedures. Endovascular treatment is probably useful if the aneurysm is inaccessible to direct surgery. Special attention must be paid to treatment because of stenotic changes in cerebral vessels within the irradiated field.

Late onset aneurysm development following radiosurgical obliteration of a cerebellopontine angle meningioma

The development of de novo intracranial aneurysms following stereotactic radiosurgery for intracranial pathology is a rare complication secondary to vascular injury. Typically, these aneurysms develop within the first few years after radiation surgery. We present the first case of an aneurysm developing 10 years after radiosurgery for a cerebellopontine angle meningioma. This case highlights the importance of careful long-term follow-up of patients who undergo radiosurgery for lesions abutting major vessels and/or who suffer post-radiation complications.

Late onset aneurysm development following radiosurgical obliteration of a cerebellopontine angle meningioma

The development of de novo intracranial aneurysms following stereotactic radiosurgery for intracranial pathology is a rare complication secondary to vascular injury. Typically, these aneurysms develop within the first few years after radiation surgery. We present the first case of an aneurysm developing 10 years after radiosurgery for a cerebellopontine angle meningioma. This case highlights the importance of careful long-term follow-up of patients who undergo radiosurgery for lesions abutting major vessels and/or who suffer post-radiation complications.

Formation and Rupture of the Internal Carotid Artery Aneurysm after Multiple Courses of Intensity-Modulated Radiation Therapy for Management of the Skull Base Ewing Sarcoma/PNET: Case Report

Background Aneurysm formation after stereotactic irradiation of skull base tumors is rare. The formation and rupture of an internal carotid artery (ICA) aneurysm in a patient with skull base Ewing sarcoma/primitive neuroectodermal tumor (PNET), who underwent surgery followed by multiple courses of intensity-modulated radiation therapy (IMRT) and chemotherapy, is described.

Case Description A 25-year-old man presented with a sinonasal tumor with intraorbital and intracranial growth. At that time cerebral angiography did not reveal any vascular abnormalities. The lesion was resected subtotally. Histopathologic diagnosis was Ewing sarcoma/PNET. The patient underwent multiple courses of chemotherapy and three courses of IMRT at 3, 28, and 42 months after initial surgery. The total biologically effective dose delivered to the right ICA was 220.2 Gy. Seven months after the third IMRT, the patient experienced profound nasal bleeding that resulted in hypovolemic shock. Angiography revealed a ruptured right C4–C5 aneurysm and irregular stenotic changes of the ICA. Lifesaving endovascular trapping of the right ICA was done. The patient recovered well after surgery but died due to tumor recurrence 6 months later.

Conclusion Excessive irradiation of the ICA may occasionally result in aneurysm formation, which should be borne in mind during stereotactic irradiation of malignant skull base tumors.