Surgical management of arteriovenous malformations in children

Natural history and clinical manifestation of Pediatric Brain Arteriovenous Malformations

Brain arteriovenous malformations (bAVMs) are aberrant arteriovenous shunts through a vascular nidus with no intervening capillary beds. They are one of the commonest causes of spontaneous intracranial haemorrhage in children and may be associated with significant morbidity and mortality in cases of rupture. Treatment strategies include microsurgical resection, endovascular embolisation, stereotactic radiosurgery, multimodality treatment with a combination thereof, and particularly in high-grade bAVMs, conservative management. Clinicians involved in treating bAVMs need to have familiarity with the natural history pertaining to bAVMs in terms of risk of rupture, risk factors elevating rupture risk as well as understanding the clinical manifestations of bAVMs. This invited review serves to provide a synthesis on natural history and clinical presentation of bAVMs with particular focus in children to inform decision-making pertaining to management.

Recurrence of brain arteriovenous malformations in pediatric patients: a long-term follow-up study

BACKGROUND

Previously thought to be congenital, AVMs have shown evidence of de-novo formation and continued growth, thus shifting thoughts on their pathophysiology. Pediatric AVM patients have been reported to be more prone to develop AVM recurrence after a seemingly complete cure. Therefore, we assessed the risk of AVM treated in childhood to recur in adulthood after a long-term follow-up in our own cohort.

METHODS

Control DS-angiography was arranged during 2021-2022 as part of a new protocol for all AVM patients who were under 21 years of age at the time of their treatment and in whom the treatment had occurred at least five years earlier. Angiography was offered only to patients under 50 years of age at the time of the new protocol. The complete eradication of AVM after the primary treatment had been originally confirmed with DSA in every patient.

RESULTS

A total of 42 patients participated in the late DSA control, and 41 of them were included in this analysis after excluding the patient diagnosed with HHT. The median age at the time of admission for AVM treatment was 14.6 (IQR 12-19, range 7-21 years) years. The median age at the time of the late follow-up DSA was 33.8 years (IQR 29.8-38.6, range 19.4-47.9 years). Two recurrent sporadic AVMs and one recurrent AVM in a patient with hereditary hemorrhagic telangiectasia (HHT) were detected. The recurrence rate was 4.9% for sporadic AVMs and 7.1% if HHT-AVM was included. All the recurrent AVMs had originally bled and been treated microsurgically. The patients with sporadic AVM recurrence had been smoking their whole adult lives.

CONCLUSIONS

Pediatric and adolescent patients are prone to develop recurrent AVMs, even after complete AVM obliteration verified by angiography. Therefore, imaging follow-up is recommended.

Recurrence of arteriovenous malformations of the brain after complete surgical resection. Kuopio University Hospital experience and systematic review of the literature

Treatment for arteriovenous malformations of the brain (bAVMs) aims to achieve complete removal or occlusion of the lesion in order to eradicate the risk of rupture and subsequent morbidity associated with these lesions. Despite initially successful treatment, bAVMs may carry a risk of recurrence especially in younger patients. We studied the rate of recurrence of surgically treated bAVMs at Kuopio University Hospital (KUH) in 1981-2021. The study population was collected retrospectively from KUH databases and presented a cohort of 135 surgically treated bAVMs with complete occlusion of the lesion. We also performed a systematic literature review on this topic. In our series, 6 out of 135 (4.4%) patients with angiographically confirmed removal of the lesion later developed a recurrent bAVM with a median time to diagnosis of recurrence of 7.46 years. In pediatric patients, the rate was 5 out of 17 (29.4%). bAVM recurrence was associated with age (p = 0.001) and initial hemorrhagic presentation (p = 0.039). Median age of the study population was 37 years (min 0, max 70), and 51/135 (37.8%) of the patients were female. Seventeen (12.6%) of the 135 bAVM patients were considered pediatric (18 years old or younger) at the time of the operation. In the literature review, 79 of 1739 (4.5%) of surgically treated patients later developed a recurrence with a mean delay of 3.1 years until diagnosis of recurrence. Young surgically treated bAVM patients with a hemorrhagic presentation at initial diagnosis are at a relatively high risk of bAVM recurrence. Follow-up imaging should be arranged for these patients in order to prevent rupture from a recurrent bAVM and subsequent morbidity.

Single-center experience with endovascular treatment of cerebral arteriovenous malformations with intent to cure in pediatric patients

PURPOSE

This study aimed to report the incidence of technical complications and immediate complete angiographic occlusion, identify associated factors with failure of complete occlusion and identify predictors of technical complications in a single-center experience of pediatric arteriovenous malformations (AVM) treated with endovascular treatment with intent to cure.

METHODS

Patients between 1 and 18 years of age undergoing endovascular embolization between 2011 and 2020 were included.

RESULTS

A total of 120 embolizations were performed in 69 patients. The most frequent clinical presentation was intracerebral hemorrhage (76.8%). Immediate obliteration of the malformations was achieved in 40 (58%) cases. The technical complication rate was 15%. AVM nidus size between 3 and 6 cm (OR: 3.91; 95% CI 1.1-13.85; p = 0.035) and the presence of multiple feeders (OR: 5.08; 95% CI 1.41-18.28; p = 0.074) were predictive of failure of immediate complete occlusion. The location of the temporal lobe (OR: 7.83; p = 0.048), deep venous drainage (OR: 4.67; p = 0.112), and the presence of an intranidal aneurysm (OR: 3.58; p = 0.134) were predictors of technical complications.

CONCLUSIONS

Embolization of pediatric AVMs with intent to cure shows a high rate of technical complications and acceptable immediate occlusion rates. Nidus size and the presence of multiple feeders were predictive of failure of complete occlusion, while temporal lobe location, deep venous drainage, and the presence of an intranidal aneurysm were predictors of technical complications. Further studies are needed to determine the best therapeutic approach in the pediatric population.

Chinese Cerebrovascular Neurosurgery Society and Chinese Interventional & Hybrid Operation Society, of Chinese Stroke Association Clinical Practice Guidelines for Management of Brain Arteriovenous Malformations in Eloquent Areas

Aim: The aim of this guideline is to present current and comprehensive recommendations for the management of brain arteriovenous malformations (bAVMs) located in eloquent areas. Methods: An extended literature search on MEDLINE was performed between Jan 1970 and May 2020. Eloquence-related literature was further screened and interpreted in different subcategories of this guideline. The writing group discussed narrative text and recommendations through group meetings and online video conferences. Recommendations followed the Applying Classification of Recommendations and Level of Evidence proposed by the American Heart Association/American Stroke Association. Prerelease review of the draft guideline was performed by four expert peer reviewers and by the members of Chinese Stroke Association. Results: In total, 809 out of 2,493 publications were identified to be related to eloquent structure or neurological functions of bAVMs. Three-hundred and forty-one publications were comprehensively interpreted and cited by this guideline. Evidence-based guidelines were presented for the clinical evaluation and treatment of bAVMs with eloquence involved. Topics focused on neuroanatomy of activated eloquent structure, functional neuroimaging, neurological assessment, indication, and recommendations of different therapeutic managements. Fifty-nine recommendations were summarized, including 20 in Class I, 30 in Class IIa, 9 in Class IIb, and 2 in Class III. Conclusions: The management of eloquent bAVMs remains challenging. With the evolutionary understanding of eloquent areas, the guideline highlights the assessment of eloquent bAVMs, and a strategy for decision-making in the management of eloquent bAVMs.

Multimodal Treatment of Pediatric Ruptured Brain Arteriovenous Malformations: A Single-Center Study

Bleeding from ruptured brain arteriovenous malformations (bAVMs) represents the most prevalent cause of pediatric intracranial hemorrhage, being also the most common initial bAVM manifestation. A therapeutic approach in these patients should aim at preventing rebleeding and associated significant morbidity and mortality. The purpose of this study was to determine the clinical outcomes of pediatric patients who initially presented at our institution with ruptured bAVMs and to review our experience with a multimodality approach in the management of pediatric ruptured bAVMs. We retrospectively reviewed pediatric patients’ medical records with ruptured bAVMs who underwent interventional treatment (microsurgery, embolization, or radiosurgery; solely or in combination) at our institution between 2011 and 2020. We identified 22 patients. There was no intraoperative and postoperative intervention-related mortality. Neither procedure-related complications nor rebleeding were observed after interventional treatment. Modified Rankin Scale (mRS) assessment at discharge revealed 19 patients (86.4%) with favorable outcomes (mRS 0–2) and 3 patients (13.6%) classified as disabled (mRS 3). Microsurgery ensured the complete obliteration in all patients whose postoperative digital subtraction angiography (DSA) was available. Management of high-grade bAVMs with radiosurgery or embolization can provide satisfactory outcomes without a high disability risk.

[Arteriovenous malformations of the brain in children: treatment results for 376 patients]

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Cerebral arteriovenous malformations (AVM) are increasingly detected in children.

Objective

To estimate the risk of hemorrhage in children with AVM before and after treatment and evaluate the outcomes of various methods of AVM management in children.

Material and methods

This study included 376 patients with various cerebral AVM under the age of 18 years. There were 273 patients with intracranial hemorrhage (72.6%).

Results

Recurrent hemorrhages within the first month were registered in 1.1% of patients with angiomatous AVM prior to treatment and in 15.4% of patients with fistulous AVM. Microsurgical resection of AVM was performed in 135 (35.9%) patients. Total resection was achieved in 97.8% of cases. There were no mortality after microsurgical procedures. Endovascular treatment was applied in 79 (21%) patients. Total embolization was achieved in 29.1% of patients. One patient (1.3%) died after endovascular procedure. Radiosurgery was performed in 140 (37.2%) patients with total obliteration after a single fraction in 64.4% of patients. Favorable long-term outcomes (GOS grades V-IV) were achieved in 89.6% of patients with available follow-up data (n=182). Recurrent hemorrhages were registered in 6% of patients (3.3% after radiosurgery, 2.7% after endovascular treatment). One patient with recurrent hemorrhage died after radiosurgery.

Conclusion

Early relapses of hemorrhage are not characteristic for children with cerebral AVM. Therefore, there are no indications for urgent surgery except for cases of intracerebral hematoma. In children, microsurgical treatment is preferred for angiomatous AVM, endovascular treatment - for fistulous AVM. Radiosurgery also ensures favorable outcomes. However, it is unreasonable to postpone AVM radiosurgical treatment in children with increased risk of recurrent hemorrhage considering relatively long period of post-radiation obliteration of AVM.

Ectopic Recurrence of Arteriovenous Malformation After Radiosurgery: Case Report and Insight Regarding Pathogenesis

BACKGROUND

While prior studies reporting de novo arteriovenous malformations after birth are not uncommon, reports of ectopic recurrence of arteriovenous malformation after radiotherapy are scarce.

CASE DESCRIPTION

An 8-year-old girl with a ruptured cerebellar arteriovenous malformation was treated with stereotactic radiosurgery. The nidus was completely obliterated 17 months after stereotactic radiosurgery; however, 20 years later she had a rupture of a recurrent nidus that occurred adjacent to the original nidus, accompanied by a radiation-induced cyst. Surgical resection was performed, and subsequent pathologic examination revealed 2 different compartments: a typical nidus and a postirradiated degenerated nidus with an encapsulated hematoma. Immunohistochemical stains showed increased expression of Ki-67 and decreased expression of endoglin in endothelial cells in the recurrent nidus.

CONCLUSIONS

Depletion in endoglin may lead to the formation of vessel malformations in the presence of angiogenic stimuli. This case serves as a strong reminder of the importance of long-term follow-up after stereotactic radiosurgery, especially for pediatric cases.

Case Report of an Obstructive Hydrocephalus Caused by an Unruptured Mesencephalic Arteriovenous Malformation in a Boy and a Review of Literature

Objective

Arteriovenous malformation (AVM) is the most common form of intracranial vascular malformations in adults. Intracranial pediatric AVMs are rare. AVM located in the vicinity of the brain stem in children are even more rare.

Case report

This study reports a rare case of acute obstructive hydrocephalus following aqueductal stenosis caused by an unruptured grade IV perimesencephalic arteriovenous malformation. An 11-year-old boy admitted to the hospital with progressive headache, nausea and vomiting throughout a month. A Computerized Tomography (CT) showed an obstructive hydrocephaly. A Magnetic Resonance (MR) imaging revealed a mesencephalic AVM compressing the aqueduct. The patient deteriorated in hours and an emergency ventriculoperitoneal shunting was performed. He did well in the early postoperative period. AVM examined with Digital Subtraction Angiography (DSA) in detail for maintaining the definitive treatment by means of endovascular embolization, microsurgery and stereotactic radiosurgery; but the patient was lost to follow up.

Conclusion

A Pubmed search revealed 34 cases of hydrocephalus caused by an unruptured AVM in the literature, and only four cases were less than 18 years old with unruptured AVM locating in brain stem or posterior fossa. Although focal neurologic deficit, seizure and headache are the most common symptoms, acute neurologic deterioration due to hydrocephalus may be the presenting symptom in these cases. The decrease in intracranial pressure by changing the flow of cerebrospinal fluid (CSF) via an emergency ventriculoperitoneal (VP) shunting or Endoscopic Third Ventriculostomy (ETV) can be a lifesaving procedure that gives a chance for further treatment modalities.

Arteriovenous Malformations in the Pediatric Population: Review of the Existing Literature

Arteriovenous malformations (AVMs) in the pediatric population are relatively rare but reportedly carry a higher rate of rupture than in adults. This could be due to the fact that most pediatric AVMs are only detected after rupture. We aimed to review the current literature regarding the natural history and the clinical outcome after multimodality AVM treatment in the pediatric population, as optimal management for pediatric AVMs remains controversial. A multidisciplinary approach using multimodality therapy if needed has been proved to be beneficial in approaching these lesions in all age groups. Microsurgical resection remains the gold standard for the treatment of all accessible pediatric AVMs. Embolization and radiosurgery should be considered as an adjunctive therapy. Embolization provides a useful adjunct therapy to microsurgery by preventing significant blood loss and to radiosurgery by decreasing the volume of the AVM. Radiosurgery has been described to provide an alternative treatment approach in certain circumstances either as a primary or adjuvant therapy.

Hemorrhage Risk in Pediatric Patients with Multiple Intracranial Arteriovenous Malformations

BACKGROUND/AIMS

This study aims to characterize the clinical features, treatment strategies, and annual hemorrhage incidence rate of pediatric patients with multiple arteriovenous malformations (MAVM).

METHODS

The PubMed and EMBASE databases and the arteriovenous malformations (AVM) database at the Johns Hopkins Hospital were searched for reports of pediatric patients (under 21 years of age) with MAVM. Data related to demographics, clinical features, management, and treatment outcomes were analyzed using descriptive statistics. Twenty-four pediatric patients met the inclusion criteria.

RESULTS

The annual hemorrhage incidence rate was 2.1%. The most common presenting features were neurological deficit (38%) and hemorrhage (21%). Treatment with embolization has become the most frequently used modality. In patients undergoing staged treatment of MAVM, hemorrhage of an untreated nidus (n = 1), visualization of a new nidus (n = 2), or disappearance of a draining vein (n = 1) occurred.

CONCLUSION

The annual hemorrhage incidence rate for pediatric patients with MAVM approaches the upper range of previously reported hemorrhage rates for solitary AVM. A staged approach to treating MAVM requires close follow-up as changes to the remaining nidi may occur during the latency period. Limitations of this study include its small sample size and reporting bias.

Outcomes of Multimodality Therapy in Pediatric Patients With Ruptured and Unruptured Brain Arteriovenous Malformations

BACKGROUND:

Brain arteriovenous malformations (BAVMs) are a frequent cause of pediatric hemorrhagic stroke, which frequently results in significant morbidity and mortality.

OBJECTIVE:

To analyze the results of multimodality treatment for a consecutive series of pediatric patients with ruptured and unruptured BAVMs at a single institution.

METHODS:

Forty patients <18 years of age were retrospectively reviewed. Results were divided by hemorrhage status, ie, ruptured or unruptured, and the intended curative treatment modality, ie, surgical resection or stereotactic radiosurgery.

RESULTS:

Twenty-seven patients (68%) presented with hemorrhage, and 13 patients (32%) presented without hemorrhage. Among ruptured patients, 19 (70%) underwent surgery and 8 (30%) underwent stereotactic radiosurgery. In surviving patients who presented with hemorrhage, 23 of 26 (88%) had a modified Rankin Scale (mRS) score of 0 to 2 at the last follow-up, and 24 of 26 (92%) obtained radiographic cure. For unruptured BAVMs, all 6 patients with grade I to III BAVM obtained radiographic cure and had an mRS score of 0 to 1 at the last follow-up, whereas 1 of 5 patients (20%) with grade IV and V BAVM had BAVM obliteration and a mean mRS score of 1.8 at the last follow-up. In a total of 93.6 years of follow-up from date of presentation to last clinical follow-up, there was 1 hemorrhage (1.1%/y). Of 30 patients with radiographic obliteration, 2 patients had radiographic recurrence (7% incidence).

CONCLUSION:

The majority of ruptured patients had an mRS score of 0 to 2 at the last follow-up and obtained radiographic cure. Unruptured patients with grade I to III BAVMs had superior outcomes compared with those with grade IV and V AVMs. Treatment of grade I to III BAVMs appears safe, and additional study is needed to determine optimal strategies for the management of unruptured grade IV and V BAVMs.

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.

Follow-up imaging to detect recurrence of surgically treated pediatric arteriovenous malformations

OBJECT

The true postoperative incidence of arteriovenous malformation (AVM) recurrence in the pediatric population remains largely unreported. Some literature suggests that delayed imaging studies should be obtained at 6 months to 1 year after negative findings on a postoperative angiogram. The aim of this study was to describe the timing of AVM recurrences after resection and the neuroimaging modalities on which the recurrences were detected.

METHODS

This study was performed in a retrospective cohort of all pediatric patients treated surgically for AVM resection by a single neurosurgeon between 2005 and 2010. Patients were followed after resection with MR angiography (MRA) or conventional angiography, when possible, at various time points. A visual scale for compactness of the initial AVM nidus was used, and the score was correlated with probability of recurrence after surgery.

RESULTS

A total of 28 patients (13 female, 15 male) underwent an AVM resection. In 18 patients (64.3%) an intraoperative angiogram was obtained. In 4 cases the intraoperative angiogram revealed residual AVM, and repeat resections were performed immediately. Recurrent AVMs were found in 4 children (14.3%) at 50, 51, 56, and 60 weeks after the initial resection. Recurrence risk was 0.08 per person-year. No patient with normal results on an angiogram obtained at 1 year developed a recurrence on either a 5-year angiogram or one obtained at 18 years of age. All patients with recurrence had a compactness score of 1 (diffuse AVM); a lower compactness score was associated with recurrence (p = 0.0003).

CONCLUSIONS

All recurrences in this cohort occurred less than 15 months from the initial resection. The authors recommend intraoperative angiography to help ensure complete resection at the time of the surgery. Follow-up vascular imaging is crucial for detecting recurrent AVMs, and conventional angiography is preferred because MRA can miss smaller AVMs. One-year follow-up imaging detected these recurrences, and no one who had negative results on an angiogram obtained at 1 year had a late recurrence. However, not all of the patients have been followed for 5 years or until 18 years of age, so longer follow-up is required for these patients. A lower compactness score predicted recurrent AVM in this cohort.

The effect of age on arteriovenous malformations in children and young adults undergoing magnetic resonance imaging

OBJECTIVE

Arteriovenous malformations (AVMs) are the most frequently encountered structural cause of spontaneous intracerebral hemorrhage in childhood, excluding hemorrhages of prematurity. The goal of our study was to examine the relationship between age and AVM prevalence on imaging in children, which to date has not been well described.

METHODS

We queried the electronic and radiographic records of 14,936 consecutive patients aged 25 years or less who had undergone brain magnetic resonance imaging (MRI) at a single institution over an 11-year period to identify those with a cerebral AVM. We collected age, gender, and other demographic characteristics for all patients. For all patients with a cerebral AVM, we recorded the location, size, drainage pattern, Spetzler-Martin grade, medical history, and presence of neurological symptoms.

RESULTS

Cerebral AVMs were identified in 55 patients (0.37%). The prevalence of AVMs detected on MRI significantly increased with age (p = 0.001). AVMs were found in 0.34% of boys (25 of 7,447) and 0.40% of girls (30 of 7,489). AVMs were most commonly identified in the frontal lobes (36%), followed by parietal (20%) and temporal lobes (13%). Sixty percent (n = 33) of AVMs were less than 3 cm in size, 35% (n = 19) were 3-6 cm in size, and 5.5% (n = 3) were greater than 6 cm in size. As for Spetzler-Martin grade of the AVMs, 25.5% were grade I, 18.2% were grade II, 36.4% were grade III, 16.4% were grade IV, and 3.6% were grade V.

CONCLUSIONS

AVMs are seen more frequently on MRI with advancing age in children and young adults.

Surgical management of pediatric cerebral arteriovenous malformations

BACKGROUND

Arteriovenous malformations (AVMs) are the most common cause of intracerebral hemorrhage in children. Different options exist for their successful management consisting of surgery, endovascular embolization, stereotactic radiosurgery, or a combination of these treatments.

DISCUSSION

In this paper, we discuss the different treatment modalities in the treatment of pediatric cerebral AVMs emphasizing the role of surgery and endovascular embolization as a preoperative strategy.

Linear vein-based arteriovenous malformations in children

OBJECT

The authors reviewed the experience of a single surgeon in the surgical treatment of arteriovenous malformations (AVMs) in children, with specific attention to the angioarchitectural appearance of these lesions. Methods The authors performed a retrospective review of pediatric cases of AVM treated at a single institution over a 15-year period. Inclusion criteria consisted of pediatric age at time of treatment and resection of a pial AVM. The AVMs were considered linear-based if they had a single, centrally located, dominant vein with a linear configuration rather than the typical central nidus.

RESULTS

Sixty-seven patients, ranging in age from 6 months to 17 years, underwent surgical treatment of an AVM between January 1, 1990, and December 30, 2005. In these patients, 31 AVMs (46%) had a distinct linear configuration that was centered on a dominant draining vein ("vein-based"). These AVMs presented with hemorrhage (61%), incidental findings on imaging (16%), or seizures (13%). In 4 cases, AVM recurrence was noted on angiographic follow-up after postoperative angiography showed no residual lesion. Recurrence was seen at 1 year in 2 cases, and at 3 and 11 years in 1 case each.

CONCLUSIONS

A linear vein-based morphological pattern is common in pediatric AVMs and may recapitulate the embryological origins of the cerebral circulation. Surgical treatment in these cases can also be vein-based, through a narrow surgical corridor, which leads to minimal cortical disruption.

Radiosurgery of brain arteriovenous malformations in children

OBJECTIVE

The authors describe their experience in treating 22 children with a single brain arteriovenous malformation (bAVM) using a dedicated LINAC stereotactic radiosurgery unit.

METHODS

The findings of 22 consecutive patients < or = 18 years of age who underwent radiosurgery for a single bAVM and with at least 24 months of follow-up, or earlier proven obliteration,were reviewed. The median age at radiosurgery was 13.8 years,with a hemorrhagic presentation in 86%. Median bAVM-volume was 1.8 ml, with a median prescribed marginal dose of 19.0 Gy.

RESULTS

The crude complete obliteration-rate was 68% (n = 15) after a median follow-up of 24 months. The actuarial obliteration- rate was 45 % after two years and 64 % after three years. Patients with a radiosurgery-based AVM score < or = 1 more frequently had an excellent outcome than patients with a bAVM score > 1 (71% vs. 20%, P = 0.12), as well as an increased obliteration rate (P = 0.03) One patient died from a bAVM-related hemorrhage 27 months after radiosurgery, representing a postradiosurgery hemorrhage rate of 1.3%/year for the complete followup interval. Overall outcome was good to excellent in 68% (n = 15). Radiation-induced changes on MR imaging were seen in 36% (n = 8) after a median interval of 12.5 months, resulting in deterioration of pre-existing neurological symptoms in one patient.

CONCLUSIONS

Radiosurgery is a relatively effective, minimally invasive treatment for small bAVMs in children. The rebleeding rate is low, provided that known predilection places for bleeding had been endovascularly eliminated.Our overall results compare unfavourably to recent pediatric microsurgical series, although comparison between series remains imprecise. Nevertheless, when treatment is indicated in a child with a bAVM that is amenable to both microsurgery or radiosurgery, microsurgery should carefully be advocated over radiosurgery, because of its immediate risk reduction.