Radiosurgical management of pediatric arteriovenous malformations

Paediatric Cerebral Arteriovenous Malformation: Outcomes from a Singapore Children's Hospital

OBJECTIVES

Paediatric brain arteriovenous malformation (bAVM) is a rare and distinct clinical entity. There is a growing body of literature that support the success of multimodality approaches for this difficult condition. The authors aim to firstly, describe our institutional experience with a consecutive series of patients and next, corroborate our results with current literature.

MATERIAL AND METHODS

This is a single institution, retrospective study conducted over a 20-year period. Patients less than 19 years old with bAVM were included. Variables of interest included patient demographics, clinical presentation, neuroimaging features, bAVM characteristics and treatment modality. Functional outcomes were measured with modified Rankin scale (mRS).

RESULTS

There were 58 paediatric bAVMs, presenting at a mean age of 8.7 ± 4.2 years, and followed up for a mean duration of 7.7 years. Thirty-six patients (62.1%) underwent microsurgical resection, 10 patients had stereotactic radiosurgery (17.2%) and 2 patients had endovascular treatment (3.4%). 50 patients (86.2%) had a favourable outcome at 1-year follow up. Microsurgical resection and SRS had similar obliteration rates (resection 83.3%; SRS 80.0%) and recurrence (resection 10.0%; SRS 12.5%). There were 6 cases of bAVM recurrence (12.8%). This subgroup was noted to be less than 7.5 years old at presentation (OR 15.0, 95% CI 1.56 - 144), and less likely to present with bAVM rupture (OR 0.11, 95% CI 0.01 - 0.96).

CONCLUSION

This study describes our experience in managing paediatric bAVM, whereby monomodal therapy can still be effective. Of note, we also demonstrate the role of extended surveillance to detect recurrence.

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.

The rationale and development of a CyberKnife© registry for pediatric patients with CNS lesions

BACKGROUND

CyberKnife© Radiosurgery (CKRS) is a recognized treatment concept for CNS lesions in adults due to its high precision and efficacy beside a high patient comfort. However, scientific evidence for this treatment modality in pediatric patients is scarce. A dedicated registry was designed to document CyberKnife© procedures in children, aiming to test the hypothesis that it is safe and efficient for the treatment of CNS lesions.

METHODS

The CyberKnife© registry is designed as a retrospective and prospective multicenter observational study (German Clinical Trials Register ( https://www.drks.de ), DRKS-ID 00016973). Patient recruitment will be ongoing throughout a 5-year period and includes collection of demographic, treatment, clinical, and imaging data. Follow-up results will be monitored for 10 years. All data will be registered in a centralized electronic database at the Charité-Universitätsmedizin. The primary endpoint is stable disease for benign and vascular lesions at 5 years of follow-up and local tumor control for malign lesions at 1- and 2-year follow-up. Secondary endpoints are radiation toxicity, side effects, and neurocognitive development.

CONCLUSION

The CyberKnife© registry intends to generate scientific evidence for all treatment- and outcome-related aspects in pediatric patients with treated CNS lesions. The registry may define safety and efficacy of CKRS in children and serve as a basis for future clinical trials, inter-methodological comparisons and changes of treatment algorithms.

[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.

Clinical Outcomes of Stereotactic Radiosurgery for Cerebral Arteriovenous Malformations in Pediatric Patients: Systematic Review and Meta-Analysis

BACKGROUND

Arteriovenous malformations (AVMs) in pediatric patients exhibit remarkable differences in terms of management and outcomes. Owing to a paucity of relevant data pertaining to AVMs in pediatric patients, special interest and investigation are required for an improved understanding of the available evidence by clinicians.

OBJECTIVE

To determine the clinical outcomes of single-session stereotactic radiosurgery (SRS) for AVMs in pediatric patients.

METHODS

A systematic literature review was performed to identify studies that reported the outcomes of SRS for AVMs in pediatric patients. Data pertaining to variables such as obliteration rate, post-SRS new hemorrhage rate, post-SRS new neurological deficit rate, and mortality rate were extracted and analyzed using meta-analysis techniques.

RESULTS

Based on pooled data from 20 studies with 1212 patients, single-session SRS resulted in complete obliteration in 65.9% (95% confidence interval [CI], 60.5%-71.1%; I2 = 66.5%) patients. Overall complication rate (including new hemorrhage, new neurodeficit, and mortality) was 8.0% (95% CI, 5.1%-11.5%; I2 = 66.4%). Post-SRS new neurological deficit rate was 3.1% (95% CI, 1.3%-5.4%; I2 = 59.7%), and post-SRS hemorrhage rate was 4.2% (95% CI, 2.5%-6.3%; I2 = 42.7%). There was no significant difference between studies disaggregated by treatment method (Gamma Knife [Elekta AB] vs other), treatment year (before year 2000 vs after year 2000), median AVM volume reported (≥3 vs <3 cm3), median dose reported (≥20 vs <20 Gy), or follow-up period (≥36 vs <36 mo).

CONCLUSION

Single-SRS is a safe treatment alternative that achieves high obliteration rates and acceptable complication rates for AVMs in pediatric patients.

Comparison of the Long-term Efficacy and Safety of Gamma Knife Radiosurgery for Arteriovenous Malformations in Pediatric and Adult Patients

It is debated whether the efficacy and long-term safety of gamma knife radiosurgery (GKRS) for arteriovenous malformations (AVMs) differs between adult and pediatric patients. We aimed to clarify the long-term outcomes of GKRS in pediatric patients and how they compare to those in adult patients. We collected data for 736 consecutive patients with AVMs treated with GKRS between 1990 and 2014 and divided the patients into pediatric (age < 20 years, n = 144) and adult (age ≥ 20 years, n = 592) cohorts. The mean follow-up period in the pediatric cohort was 130 months. Compared to the adult patients, the pediatric patients were significantly more likely to have a history of hemorrhage (P < 0.001). The actuarial rates of post-GKRS nidus obliteration in the pediatric cohort were 36%, 60%, and 87% at 2, 3, and 6 years, respectively. Nidus obliteration occurred earlier in the pediatric cohort than in the adult cohort (P = 0.015). The actuarial rates of post-GKRS hemorrhage in the pediatric cohort were 0.7%, 2.5%, and 2.5% at 1, 5, and 10 years, respectively. Post-GKRS hemorrhage was marginally less common in the pediatric cohort than in the adult cohort (P = 0.056). Cyst formation/encapsulated hematoma were detected in seven pediatric patients (4.9%) at a median post-GKRS timepoint of 111 months, which was not significantly different from the rate in the adult cohort. Compared to adult patients, pediatric patients experience earlier therapeutic effects from GKRS for AVMs, and this improves long-term outcomes.

Clinical outcomes and radiosurgical considerations for pediatric arteriovenous malformation: influence of clinical features on obliteration rate

PURPOSE

Gamma knife radiosurgery (GKRS) is an established treatment modality for brain arteriovenous malformation (AVM), but there have been few published studies examining the relationship between clinical features of AVM and successful obliteration with GKRS in pediatric patients. In the current study, we investigate the outcomes of GKRS for pediatric patients with brain AVM and analyze the variables that influence obliteration.

METHODS

We analyzed 68 pediatric patients (≤ 18 years) with a mean follow-up period of 61.9 months (range 6-215 months). The following parameters were analyzed to determine their influence on obliteration of AVM treated by GKRS: age, sex, target volume, irradiation dose, prior treatment, location of AVM, nidus structure, velocity of AVM, location of venous drainage, number of feeding arteries, and initial presenting symptoms. Also, we estimated clinical factors which should be considered during the follow-up period.

RESULTS

Of the 68 patients, complete obliteration was confirmed in 26 (38.2%) by cerebral angiography. The response rate of AVM for GKRS was 92.6%. No significant association was observed between any of the parameters investigated and the obliteration of AVM, with the exception of number of feeding arteries, which exhibited a statistically significant difference by univariate analysis (p = 0.003). However, on multivariate analysis, nidus structure (p = 0.007), velocity of the main arterial phase (p = 0.013), velocity of the feeding artery phase (p = 0.004), and the number of feeding arteries (p = 0.018) showed statistical significance.

CONCLUSION

GKRS yielded good long-term clinical outcomes in most pediatric patients. Multiple arterial feeding vessels, diffuse nidus structure, and fast flow of AVM were specific factors associated with a low rate of obliteration in pediatric AVMs.

Linear Accelerator Stereotactic Radiosurgery of Central Nervous System Arteriovenous Malformations: A 15-Year Analysis of Outcome-Related Factors in a Single Tertiary Center

BACKGROUND

Linear accelerator stereotactic radiosurgery is one of the modalities available for the treatment of central nervous system arteriovenous malformations (AVMs). The aim of this study was to describe our 15-year experience with this technique in a single tertiary center and the analysis of outcome-related factors.

METHODS

From 1998 to 2013, 195 patients were treated with linear accelerator-based radiosurgery; we conducted a retrospective study collecting patient- and AVM-related variables. Treatment outcomes were obliteration, posttreatment hemorrhage, symptomatic radiation-induced changes, and 3-year neurologic status. We also analyzed prognostic factors of each outcome and predictability analysis of 5 scales: Spetzler-Martin grade, Lawton-Young supplementary and Lawton combined scores, radiosurgery-based AVM score, Virginia Radiosurgery AVM Scale, and Heidelberg score.

RESULTS

Overall obliteration rate was 81%. Nidus diameter and venous drainage were predictive of obliteration (P < 0.05), ruptured status and previous embolization were not related to rate of obliteration, and low-grade AVMs had higher obliteration rates. Posttreatment hemorrhage incidence was 8.72%; nidus diameter was the only predictor (P = 0.05). Symptomatic radiation-induced changes occurred in 11.79% of patients and were significantly associated with unruptured status (P < 0.05). Treatment success as a composite measure was obtained in 70.77% of patients. Receiver operating characteristic curves were presented for each scoring system and outcome measure; best area under the curve was 0.687 for Lawton combined score in the obliteration outcome.

CONCLUSIONS

In the long-term, linear accelerator-based radiosurgery is a useful, valid, effective, and safe modality for treatment of brain AVMs.

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.

Leksell Gamma Knife for pediatric and adolescent cerebral arteriovenous malformations: results of 100 cases followed up for at least 36 months

OBJECT

The goal of this study was to evaluate advantages, risks, and failures of Gamma Knife radiosurgery (GKRS) in a large series of pediatric and adolescent patients with cerebral arteriovenous malformations (cAVMs) who were followed up for at least 36 months.

METHODS

Since February 1993, 100 pediatric and adolescent patients (≤ 18 years of age) with cAVMs have undergone GKRS at the authors' institution and were followed up for at least 36 months. Forty-six patients were boys and 54 were girls; the mean age was 12.8 years (range 3-18 years). Hemorrhage, either alone or combined with seizure, was the clinical onset in 70% of cases. The mean pre-GK cAVM volume was 2.8 ml; 92% of cAVMs were Spetzler-Martin (S-M) Grades I-III. Most lesions (94%) were in eloquent or deep-seated brain regions, according to S-M classification. The parameters for mean and range in treatment planning were prescription isodose 53.8% (40%-90%); prescription dose (PD) 20.2 Gy (9.0-26.4 Gy); maximal dose (MD) 37.8 Gy (18-50 Gy); and number of shots 4.7 (1-17). On the day of GKRS, stereotactic CT or stereotactic MRI and digital subtraction angiography were used.

RESULTS

Obliteration rate (OR) was angiographically documented in 75 of 84 cases (89.3%) after single-session GKRS, with actuarial ORs at 3 and 5 years of 68.0% and 88.1%, respectively. A repeat treatment was performed in 7 patients (6 with obliteration), and 16 patients with cAVMs underwent staged treatment (9 of them were angiographically cured). Thus, the overall OR was 90%, with actuarial ORs at 3, 5, and 8 years of 59.0%, 76.0%, and 85.0%, respectively. Permanent symptomatic GK-related complications were observed in 11% of cases, with surgical removal of enlarged mass seen on post-RS imaging needed in 5 cases. Hemorrhage during the latency period occurred in 9% of patients, but surgical evacuation of the hematoma was required in only 1 patient. One patient died due to rebleeding of a brainstem cAVM. Radiosurgery outcomes varied according to cAVM sizes and doses: volumes ≤ 10 ml and PDs > 16 Gy were significantly associated with higher ORs and lower rates of permanent complication and bleeding during the latency period.

CONCLUSIONS

The data from this study reinforce the conclusion that GKRS is a safe and effective treatment for pediatric and adolescent cAVMs, yielding a high OR with minimal permanent severe morbidity and no mortality. The very low frequency of severe hemorrhages during the latency period further encourages a widespread application of RS in such patients. Univariate analysis found that modified RS-based cAVM score, nidus volume, PD, integral dose, S-M grade, and preplanned treatment (the last 2 parameters were also confirmed on multivariate analysis) significantly influenced OR. Lower S-M grades and single-session planned treatments correlated with shorter treatment obliteration interval on univariate analysis. This statistical analysis suggests that a staged radiosurgical treatment should be planned when nidus volume > 10 ml and/or when the recommended PD is ≤ 16 Gy.

Transvenous Embolization in Pediatric Plexiform Arteriovenous Malformations

BACKGROUND:

Transvenous embolization is a developing concept for curative therapy of cerebral arteriovenous malformations (AVMs). The feasibility of this endovascular method has not been reported in children.

OBJECTIVE:

To report our experience treating pediatric AVMs with the transvenous approach (TVA).

METHODS:

A cohort of 7 pediatric patients (younger than 18 years of age) who underwent the TVA for cerebral AVMs between January 2012 and January 2014. The TVA was used alone or in conjunction with other arterial approaches in definitive embolization sessions. Patient demographics, AVM characteristics, clinical outcomes, and angiographic results were independently assessed. Pial arteriovenous fistulae and vein of Galen malformations were excluded. Control angiograms were obtained at 6 months, and curative treatment was determined by the anatomic obliteration of the nidus.

RESULTS:

All patients had anatomic exclusion of the AVM. The mean size was 2 ± 0.6 cm, and hemorrhage was the most common presentation (100%, n = 7). Most AVMs were deeply placed (71%, n = 5), and a proximal approach to the nidus was achieved in all cases. Transvenous embolization alone was performed in 3 patients (43%), whereas combined arterial and venous embolization was required in 4 patients (57%). The mean follow-up period was 20.2 ± 10.5 months. There were no hemorrhagic or thromboembolic events, and venous infarction was not documented. No recurrence was documented.

CONCLUSION:

This is the first report that demonstrates the feasibility of transvenous Onyx embolization of AVMs in the pediatric population. Such a technique may be considered in certain AVMs that meet anatomic criteria in which microsurgery and radiosurgery might not be indicated.

Safety and efficacy using a detachable tip microcatheter in the embolization of pediatric arteriovenous malformations

PURPOSE

The treatment of deep-seeded pediatric brain arteriovenous malformations (AVMs) remains a challenging task. We describe our experience using a new detachable tip microcatheter in the embolization of brain arteriovenous malformations, pial arteriovenous fistulas, and vein of Galen malformations. We describe the safety and efficacy using a new detachable tip microcatheter in the treatment of pediatric deep brain arteriovenous malformations, pial malformations, and vein of Galen malformations.

METHODS

During a period of 9 months from March 2013 through January 2014, 11 pediatric patients in 14 procedures with 27 total injections were selected for treatment with a detachable tip under Food and Drug Administration (FDA) compassionate use exemption and were admitted to our department for treatment of their brain AVM using a liquid embolic agent and a detachable tip microcatheter. The ages of the patients ranged from 3 months to 18 years old.

RESULTS

Of the 27 total injections done, the tip detached in seven cases. For the 16 n-BCA injections, the tip detached six times (37.5 %), and for the 11 Onyx injections, the tip detached one time (9 %). There were no cases of premature microcatheter detachment during normal vessel navigation.

CONCLUSIONS

The introduction of these detachable tip microcatheters allows for a safe and relaxed injection that permits a true circumferential occlusion, and may further permit filling a larger amount of angioarchitecture without the risk of distal migration, or vessel damage during the usual rapid removal of non detachable micocatheters.

Angiographic features help predict outcome after stereotactic radiosurgery for the treatment of pediatric arteriovenous malformations

PURPOSE

Arteriovenous malformations (AVMs) are a frequent cause of hemorrhagic stroke in children. Stereotactic radiosurgery (SRS) is an established treatment for these lesions, particularly those that are surgically inaccessible. Because only complete AVM obliteration is believed to protect against the future risk of hemorrhage, identifying lesion characteristics that predict response to therapy is an important objective. The goal of this study is to evaluate the influence of angiographic features of AVMs on the rate of obliteration following treatment with SRS.

METHODS

This is a retrospective cohort study of pediatric patients (age ≤18 years) treated with Gamma Knife SRS for cerebral AVMs between 2000 and 2012. Detailed angiographic data at the time of initial angiographic evaluation were prospectively recorded by experienced neurointerventional radiologists. The primary outcome was the rate of obliteration on a 3-year follow-up angiogram.

RESULTS

We identified 42 pediatric patients treated with SRS for cerebral AVMs. Twenty-seven patients completed 3-year angiographic follow-ups. Complete obliteration was seen in 30%, partial response in 67%, and no response in 4%. Higher SRS dose was associated with complete obliteration. Larger AVM diameter, presence of multiple draining veins, and presence of multiple draining veins reaching a sinus were associated with partial response. In this small cohort, diffuse AVM borders, presence of aneurysm, and pre-SRS embolization were not associated with obliteration.

CONCLUSIONS

Our study identifies AVMs in the pediatric population with a nidus diameter of <2.5 cm and a solitary draining vein as the most likely to undergo complete obliteration after SRS treatment.

Stereotactic linac radiosurgery and hypofractionated stereotactic radiotherapy for pediatric arteriovenous malformations of the brain: experiences of a single institution

PURPOSE

The aim of our study was to evaluate treatment results and toxicity of stereotactic irradiation for arteriovenous malformations (AVMs) in children.

METHODS

A group of ten consecutive children (four boys and six girls) irradiated between 2002 and 2010 at our institution was included into the study. The mean age at the time of treatment was 15.4 and ranged between 8 and 18 years. There were two Spetzler-Martin grade IV, four grade III, and four grade II lesions. Mean AVM volume was 13.2 cm(3) and varied from 0.6 to 36.8 cm(3). In five patients, the planned dose of 16-20 Gy was delivered in single fraction, in five the total dose of 16-24 Gy was delivered in two to three fractions. One patient was reirradiated with a dose of 15 Gy, 7 years after the initial treatment.

RESULTS

The median follow-up was 38.5 months. The treatment resulted in total obliteration in eight patients and partial in one. The median time to obliteration was 22 months; actuarial total obliteration rates were 20, 54, 54, and 83 % after 1, 2, 3, and 4 years of follow-up, respectively. No patient bled after the treatment. In one patient, new epileptic seizures developed after the treatment; in magnetic resonance imaging, focal necrosis was revealed. In five patients, asymptomatic imaging abnormalities were seen during follow-up.

CONCLUSIONS

Stereotactic radiotherapy appears to be an effective method of treatment for pediatric AVMs, the patients however require meticulous follow-up because of relative high incidence of radiation-induced imaging abnormalities.

Gamma knife surgery for pediatric arteriovenous malformations: a 25-year retrospective study

OBJECT

The authors present their 25-year experience in treating pediatric arteriovenous malformations (AVMs) to allow comparisons with other historic studies and data in adults.

METHODS

Data were collected from a prospectively maintained departmental database selected for age and supplemented by case note review and telephone interviews as appropriate.

RESULTS

Three hundred sixty-three patients, ages 1-16 years (mean ± SD, 12 ± 3.2 years), underwent 410 treatments; 4 had planned 2-stage treatments and 43 were retreated subsequent to an initial partial response. Fifty-eight percent received general anesthesia for the procedure. Sixteen percent had previously undergone embolization. The most common presenting symptoms were as follows: hemorrhage (80.2%), epilepsy (8.3%; overall seizure prevalence 19.9%), and migrainous headaches (6.3%). Only 0.28% of the AVMs were incidental findings. The mean lesion volume was 3.75 ± 5.3 cm3 (range 0.01-32.8 cm3), with a median Spetzler-Martin grade of III (range I-V). The mean peripheral (therapeutic) dose was 22.7 ± 2.3 Gy (range 15-25 Gy), corresponding to a mean maximum dose of 43.6 ± 6 Gy (range 25-51.4 Gy). The obliteration rate was 71.3% in patients who received one treatment and 62.5% for retreated patients, with a mean obliteration time of 32.4 and 79.6 months, respectively. The overall obliteration rate was 82.7%. No follow-up data are as yet available for the 4 patients who underwent the staged treatments. Only 4 patients received peripheral doses below 20 Gy, and the AVM was obliterated in 3 of these patients. The other patients received 20, 22.5, or 25 Gy and had obliteration rates of 82.6%, 77.7%, and 86.3%, respectively. The bleeding rate postradiosurgery was 2.2%, and the cumulative complication rate was 3.6%, with radionecrosis being the most common complication (1.1%).

CONCLUSIONS

Surprisingly, there was no correlation (p = 0.43) between outcome and radiosurgical dose when that dose was between 20 and 25 Gy, thus suggesting that the lower of these 2 doses may be effective. Radiosurgery for pediatric AVM is safe and effective.

Paediatric Stroke: Review of the Literature and Possible Treatment Options, including Endovascular Approach

Stroke is among the top 10 causes of death in childhood. More than half of the surviving children have long-term neurological sequelae. Ischemic stroke (IS) includes arterial ischemic stroke and cerebral venous thrombosis with venous infarction. Haemorrhagic stroke (HS) includes intracerebral haematoma or subarachnoid haemorrhage. Risk factors for stroke are different in children and in adults. 10–30% of IS have no identified risk factors. However, multiple risk factors are recognizable in the majority of stroke in children; thus, a comprehensive diagnostic evaluation is crucial. Vascular abnormalities, such as arteriovenous malformations, aneurysms, vessel dissection, stenosis, and moyamoya disease, are frequently associated with both IS and HS and lead to high recurrence rates. Endovascular and surgical treatment options are sometimes indicated, performed on the basis of expert opinion, and extrapolated from the adult procedures. In the present paper, we review the recent literature and we discuss the treatment in five cases managed at our institutions.

Clinico-radiological outcomes following gamma knife radiosurgery for pediatric arteriovenous malformations

PURPOSE

The aim of this study was to evaluate clinico-radiological outcomes following gamma knife radiosurgery (GKS) for pediatric arteriovenous malformations (AVMs).

METHODS

The present series included 39 children (3-17 years of age) who underwent GKS for cerebral AVMs between January 2002 and February 2008. Twenty-five patients presented with hemorrhages. The median AVM volume was 1.5 cm³, and the median marginal dose was 20 Gy. All patients continued to have follow-up for more than 24 months with serial magnetic resonance images (MRIs)/angiograms. Current school performance has been evaluated using a telephone survey answered by the patients' parents.

RESULTS

Follow-up angiograms, available in 34 patients, confirmed complete obliteration in 16 patients. Serial MRIs indicated obliteration of the nidus in one of five patients without angiography. The diffuse nidus structure and low marginal dose were significantly associated with incomplete obliteration. Twelve patients underwent a second GKS, and subsequent angiographies, available in six patients, demonstrated complete obliteration in two of them. Complications included new-onset seizures (n = 1), apraxia (n = 1), and temporal horn entrapment requiring a shunt operation (n = 1). School performance declined in 14 out of 32 patients. Both the AVM volume and modified AVM score were found to be reliable predictors of school performance.

CONCLUSIONS

The results of the present study substantiate the diffuse and other atypical features of pediatric AVMs as major determinants of treatment failure following GKS. Considering the apparent declination of school performance, future prospective studies would be required to investigate the possible late-effects of GKS on neuropsychological function.