Neurosurgical vascular malformations in children under 1 year of age

Pediatric non-galenic pial arteriovenous fistula's characteristics and outcomes: a systematic review

INTRODUCTION

Pediatric non-galenic pial arteriovenous fistulas (pAVFs) are rare vascular malformations that are characterized by a pial arterial-venous connection without an intervening capillary bed. Outcomes and treatment strategies for pAVFs are highly individualized, owing to the rarity of the disease and lack of large-scale data guiding optimal treatment approaches.

METHODS

We performed a systematic review of pediatric patients (< 18 years at diagnosis) diagnosed with a pAVF by digital subtraction angiogram (DSA). The demographics, treatment modalities, and outcomes were documented for each patient and clinical outcome data was collected. Descriptive information stratified by outcome scores were classified as follows: 1 = excellent (no deficit and full premorbid activity), 2 = good (mild deficit and full premorbid activity), 3 = fair (moderate deficit and impaired activity), 4 = poor (severe deficit and dependent on others), 5 = death.

RESULTS

A total of 87 studies involving 231 patients were identified. Median age at diagnosis was 3 years (neonates to 18 years). There was slight male preponderance (55.4%), and 150 subjects (81.1%*) experienced excellent outcomes after treatment. Of the 189 patients treated using endovascular approaches, 80.3% experienced excellent outcomes and of the 15 patients surgically treated subjects 75% had an excellent outcome. The highest rate of excellent outcomes was achieved in patients treated with Onyx (95.2%) and other forms of EvOH (100%). High output heart failure and comorbid vascular lesions tended to result in worse outcomes, with only 54.2% and 68% of subjects experiencing an excellent outcome, respectively. *Outcomes were reported in only 185 patients.

CONCLUSION

pAVFs are rare lesions, necessitating aggregation of patient data to inform natural history and optimal treatment strategies. This review summarizes the current literature on pAVF in children, where children presenting with heart failure as a result of high flow through the lesion were less likely to experience an excellent outcome. Prospective, large-scale studies would further characterize pediatric pAVFs and enable quantitative analysis of outcomes to inform best treatment practices.

Use of greyscale and Doppler ultrasound in initial evaluation and follow-up of neurovascular malformations in children

Pediatric intracranial arteriovenous shunts are rare vascular malformations that can be diagnosed prenatally or postnatally, as an incidental finding or due to complications. We propose a review of cerebral vascular malformations in newborns and infants with special emphasis on neurosonography and Doppler ultrasound as the first diagnostic method. Sonography can thus contribute in the planning of further studies that are always necessary, and in post-therapy follow-up.

Expect the unexpected: a case of spontaneous thrombosis of a pial arteriovenous fistula in a preterm newborn with review of the literature

INTRODUCTION

Pial arteriovenous fistulas (pAVF) are rare vascular malformations, especially in children and newborns. In neonates, the most common symptom is congestive heart failure.

CASE PRESENTATION

We report a case of an asymptomatic preterm newborn incidentally diagnosed with pAVF during a routine cranial ultrasound (cUS) on the third day of life. Cerebral magnetic resonance (MRI) confirmed the diagnosis. A wait-and-see approach was chosen by the multidisciplinary team. The cUS and the MRI on day 14 of life showed the spontaneous resolution of the lesion.

CONCLUSIONS

This case underlines the challenges in identifying pAVF in the first weeks of life and demonstrates a possible positive outcome for affected neonates.

Spinal cord motor disorders

Spinal cord diseases are frequently devastating due to the precipitous and often permanently debilitating nature of the deficits. Spastic or flaccid paraparesis accompanied by dermatomal and myotomal signatures complementary to the incurred deficits facilitates localization of the insult within the cord. However, laboratory studies often employing disease-specific serology, neuroradiology, neurophysiology, and cerebrospinal fluid analysis aid in the etiologic diagnosis. While many spinal cord diseases are reversible and treatable, especially when recognized early, more than ever, neuroscientists are being called to investigate endogenous mechanisms of neural plasticity. This chapter is a review of the embryology, neuroanatomy, clinical localization, evaluation, and management of adult and childhood spinal cord motor disorders.

Outcomes of endovascular embolization for Vein of Galen malformations: An individual participant data meta-analysis

Introduction

Understanding outcomes after Vein of Galen malformation (VOGM) embolization has been limited by small sample size in reported series and predominantly single center studies. To address these limitations, we perform an individual-participant meta-analysis (IPMA) to identify risk factors associated with all-cause mortality and clinical outcome after VOGM endovascular embolization.

Methods

We performed a systematic review and IPMA of VOGM endovascular outcomes according to PRISMA guidelines. Individual patient characteristics including demographic, intra/post-operative adverse events, treatment efficacy (partial or complete occlusion), and clinical outcome were collected. Mixed-effects logistic regression with random effects modeling and Bonferroni correction was used (p ≤ 0.003 threshold for statistical significance). The primary and secondary outcomes were all-cause mortality and poor clinical outcome (moderate/severe developmental delay or permanent disabling injury), respectively. Data are expressed as (mean ± standard deviation (SD)) or (odds ratio (OR), 95% confidence interval (CI), I 2, p-value).

Results

Thirty-five studies totaling 307 participants quantifying outcomes after endovascular embolization for VOGM were included. Follow up time was 42 (±57) months. Our analysis contained 42% neonates (<1 month) at first embolization, 45% infants (1 month ≤2 years), and 13% children (>2 years). Complete occlusion was reported in 48% of participants. Overall all-cause mortality was 16%. Overall, good clinical outcome was achieved in 68% of participants. First embolization as a neonate [OR = 6.93; 95% CI (1.99-24.08); I 2 < 0.01; p < 0.001] and incomplete embolization [OR = 10.87; 95% CI (1.86-63.55); I 2 < 0.01; p < 0.001] were associated with mortality. First embolization as a neonate [OR = 3.24; 95% CI (1.47-7.15); I 2 < 0.01; p < 0.001], incomplete embolization [OR = 5.26; 95% CI (2.06-13.43); I 2 < 0.01; p < 0.001], and heart failure at presentation [OR = 3.10; 95% CI (1.03-9.33); I 2 < 0.01; p = 0.002] were associated with poor clinical outcomes. Sex, angioarchitecture of lesion, embolization approach (transvenous vs. transarterial), and single or multistage embolization were not associated with mortality or clinical outcome.

Conclusions

We identify incomplete VOGM embolization independently associated with mortality and poor clinical outcome. While this study provides the highest level of evidence for VOGM embolization to date, prospective multicenter studies are needed to understand the optimal treatment strategies, outcomes, and natural history after VOGM embolization.

Giant dural arteriovenous fistula in a pediatric patient: positive outcome following surgical treatment

PURPOSE

Our purpose is to present an atypical case of a 4-month-old patient with a giant dural arteriovenous fistula (DAVF).

METHODS

Presentation of a case report and review of the literature.

RESULTS

The DAVF arterial supply was through the middle meningeal artery bilaterally and the anterior and middle cerebral arteries on the right hemisphere. The venous drainage was through the posterior two-thirds of the superior sagittal sinus. The endovascular team performed an embolization to reduce the flow of the lesion, and finally, the surgical team completed the excision of the residual venous sac, without causing any significant neurological deficit. We used a double surgical approach done with two surgical teams in order to optimize the hemostasis control and reduce morbidity and mortality.

CONCLUSION

Midline DAVF usually has devastating consequences in children. Endovascular treatment is the first choice since it has lower mortality. Nevertheless, it requires multiple interventions, and the cure of the disease may not be achieved. We believe that joint endovascular and surgical treatment, supported by a reliable multidisciplinary medical team, is a good option for this type of lesions.

Galenic Pial Arteriovenous Fistulas in Adults

BACKGROUND

Vein of Galen aneurysmal malformations (VOGMs) are pial arteriovenous fistulas possessing Galenic venous drainage most commonly presenting during the neonatal period and infancy, with initial discovery during adulthood quite rare.

OBJECTIVES AND METHODS

We conducted a literature survey of the PubMed database in order to identify Galenic pial arteriovenous fistulas (GPAVFs) with major manifestation or initial presentation during adulthood. Inclusionary criteria included pial AVFs with Galenic drainage with major manifestation or initial presentation at, or older than, 18 years. Exclusionary criteria included exclusive pediatric onset of symptomatology attributable to GPAVFs without a new onset major presentation during adulthood, exclusive or major dural arterial supply, arteriovenous malformations with Galenic drainage, developmental venous anomalies with Galenic drainage, isolated varices or anomalies of the vein of Galen, and any lesions with uncertainty regarding true GPAVF nature.

RESULTS

Our search generated 1589 articles. Excluding duplicates, 26 cases met criteria for evaluation. Mean age was 34.1 +/- 2.53 years. Clinical presentations of GPAVFs among adults included headache, intracranial hemorrhage, seizures, and focal neurologic deficits. Management strategies included observation (n = 5), emergent ventriculostomy or Torkildsen shunt (n = 3), cerebrospinal fluid diversion via ventriculoperitoneal shunting (n = 4), microsurgical obliteration or thrombectomy (n = 4), transarterial and/or transvenous embolotherapeutic obliteration (n = 7), and concurrent embolotherapy and radiosurgical irradiation (n = 1).

CONCLUSIONS

GPAVFs in adults often present with symptomatology of mild severity and may be effectively managed conservatively, though occasionally present catastrophically or may be treated via cerebrospinal fluid diversion, microsurgical obliteration, or endovascular embolization. Severity sufficient to require emergent intervention portended a poor outcome.

Endovascular Treatment of Vein of Galen Malformations: A Systematic Review and Meta-Analysis

BACKGROUND

Outcomes after endovascular embolization of vein of Galen malformations remain relatively poorly described.

PURPOSE

We performed a systematic review of the literature to determine outcomes and predictors of good outcomes following endovascular treatment of vein of Galen malformations.

DATA SOURCES

We used Ovid MEDLINE, Ovid Embase, and the Web of Science.

STUDY SELECTION

Our study consisted of all case series with ≥4 patients receiving endovascular treatment of vein of Galen malformations published through January 2017.

DATA ANALYSIS

We studied the following outcomes: complete/near-complete occlusion rates, technical complications, perioperative stroke, perioperative hemorrhage, technical mortality, all-cause mortality, poor neurologic outcomes, and good neurologic outcomes. Outcomes were stratified by age-group (neonate, infant, child). A random-effects meta-analysis was performed.

DATA SYNTHESIS

A total of 27 series with 578 patients were included; 41.9% of patients were neonates, 45.0% of patients were infants, and 13.1% of patients were children. All-cause mortality was 14.0% (95% CI, 8.0%-22.0%). Overall good neurologic outcome rates were 62.0% (95% CI, 57.0%-67.0%). Overall poor neurologic outcome rates were 21.0% (95% CI, 17.0%-26.0%). Neonates were significantly less likely to have good neurologic outcomes than infants (48.0%; 95% CI, 35.0%-62.0% versus 77.0%; 95% CI, 70.0%-84.0%; P < .01). Treatment indications following the Bicêtre neonatal evaluation score resulted in significantly higher rates of good neurologic outcome (P = .04). Patients with congestive heart failure had significantly lower rates of good neurologic outcome (OR, 0.50; 95% CI, 0.28-0.88; P = .01).

LIMITATIONS

Limitations were selection and publication biases.

CONCLUSIONS

Patients receiving endovascular embolization of vein of Galen malformations experienced good long-term clinical outcomes in >60% of cases. Appropriate patient selection is key as treatment guided by the Bicêtre neonatal evaluation score was associated with improved neurologic outcomes.

Cerebral Arteriovenous Malformation Detected by Newborn Congenital Heart Disease Screen with Echocardiography

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CCHD screening may produce “false-positive” results due to extracardiac causes.

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Cerebral arteriovenous malformations can cause increased cerebral venous return.

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The anterior fontanelle provides a unique ultrasound window in newborns.

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Echocardiography detected a cerebral AVM in a newborn with a failed CCHD screen.

Prenatal Diagnosis and Multimodal Neonatal Treatment of a Rare Pial Arteriovenous Fistula: Case Report and Review of the Literature

BACKGROUND

Intracranial pial arteriovenous fistulas (PAVFs) are direct communications between the arterial and venous system of the brain, with the characteristic absence of a plexiform nidus, as seen in the classic cerebral arteriovenous malformations. These vascular malformations, usually occurring in the pediatric population, very rarely are diagnosed in utero, because of a lack of understanding of the condition and because they may be hard to visualize.

CASE DESCRIPTION

We report a rare case of a mass-effect PAVF diagnosed with fetal magnetic resonance imaging, involving the right cerebral hemisphere, fed by a pericallosal artery and associated with a giant venous dilatation. The PAVF initially was managed by the endovascular embolization. The recruitment of a middle cerebral artery feeder and the rapidly enlarging size of the venous pouch with mass effect required subsequent surgery.

CONCLUSIONS

The 2-stage multimodal treatment resulted in complete disappearance of the PAVF without complications.

Hydrocephalus in a patient with an unruptured pial arteriovenous fistula: hydrodynamic considerations, endovascular treatment, and clinical course

Intracranial pial arteriovenous fistulas, also known as nongalenic fistulas, are rare vascular malformations affecting predominantly the pediatric population. Hydrocephalus is an unusual presentation in which the exact pathophysiology is not fully understood. The aim of treatment in these cases is occlusion of the fistula prior to considering ventricular shunting. Here, the authors describe the hydrodynamic considerations of the paravascular pathway and the resolution of hydrocephalus with endovascular treatment of the fistula.

The natural progression of VGAMs and the need for urgent medical attention: a systematic review and meta-analysis

Background

Vein of Galen aneurysmal malformations (VGAMs) are congenital disorders that may require emergency treatment and some may cause sudden death before medical attention is provided. Some patients also have a spontaneous thrombosis.

Objective

To understand the natural progression of VGAMs through a systematic literature review.

Methods

We examined PubMed to identify studies published between July 1973 and March 2015. We determined the proportion of patients with VGAM who died before receiving medical attention, who received emergency treatment, or had a spontaneous thrombosis. We pooled estimates of proportions with corresponding 95% CIs calculated using the raw (ie, untransformed) proportions.

Results

The 31 studies obtained described the outcome of 754 patients with VGAM. The probability of sudden death risk was 4% (95% CI 1% to 7%; I2=51.6%); of an emergency operation was 46% (95% CI 34% to 58%; I2=93.2%); and of spontaneous thromboses 1% (95% CI 0% to 2%; I2=0%) of cases. Differences between age and clinical outcomes of patients with spontaneous thromboses were significant according to the rank test (Mann–Whitney U test, Z=−2.398, p=0.016), both having a linear correlation (χ2 test, p=0.022).

Conclusions

Over time, the rate of preoperative sudden death in patients with VGAM gradually declined and the rate of emergency operations gradually increased. The outcome of patients with early spontaneous thromboses was good. Our study provides a definitive description of the natural progression of VGAMs and the need for urgent medical attention.

Outcome and complications of endovascular embolization for vein of Galen malformations: a systematic review and meta-analysis

OBJECT

There have been many multidisciplinary approaches to the treatment of vein of Galen malformations. Endovascular embolization is the first option for treatment. However, the effects of the treatment remain controversial. The aim of this study is to assess the efficacy and safety of endovascular embolization to treat patients with vein of Galen malformations.

METHODS

This paper includes a retrospective analysis of a sample of 667 patients who underwent endovascular embolization to treat vein of Galen malformations. The data were obtained through a literature search of PubMed databases. The authors also evaluate the efficacy and safety of the treatment. Mortality within the follow-up period is analyzed. Pooled estimates of proportions with corresponding 95% CIs were calculated using raw (i.e., untransformed) proportions (PRAW).

RESULTS

In the 34 studies evaluated, neonates accounted for 44% of the sample (95% CI 31%-57%; I(2) = 92.5%), infants accounted for 41% (95% CI 30%-51%; I(2) = 83.3%), and children and adults accounted for 12% (95% CI 7%-16%; I(2) = 52.9%). The meta-analysis revealed that complete occlusion was performed in 57% (95% CI 48%-65%; I(2) = 68.2%) of cases, with partial occlusion in 43% (95% CI 34%-51%; I(2) = 70.7%). The pooled proportion of patients showing a good outcome was 68% (95% CI 61%-76%; I(2) = 77.8%), while 31% showed a poor outcome (95% CI 24%-38%; I(2) = 75.6%). The proportional meta-analysis showed that postembolization mortality and complications were reported in 10% (95% CI 8%-12%; I(2) = 42.8%) and 37% (95% CI 29%-45%; I(2) = 79.1%), respectively. Complications included cerebral hemorrhage, cerebral ischemia, hydrocephalus, leg ischemia, and vessel perforation.

CONCLUSIONS

The successful treatment of vein of Galen malformations remains a complex therapeutic challenge. The authors' analysis of clinical history and research literature suggests that vein of Galen malformations treated with endovascular embolization can result in an acceptable mortality rate, complications, and good clinical outcome. Future large-scale, multicenter, randomized trials are necessary to confirm these findings.

The role of percutaneous embolization techniques in the management of dural sinus malformations with atypical angioarchitecture in neonates: report of 2 cases

Dural sinus malformations (DSMs) are rare congenital malformations that can be midline or lateral in location. Midline DSMs have been reported to have a worse prognosis than lateral DSMs and have traditionally been more difficult to manage. The authors report 2 unusual manifestations of midline DSMs and their management with percutaneous transfontanelle embolization. The first patient (Case 1) presented at 21 days of life with a large midline DSM and multiple highflow dural and pial arteriovenous shunts. The child developed congestive cardiac failure and venous congestion with intracranial hemorrhage and seizures within a few weeks. The second patient (Case 2) presented with a large midline DSM found on prenatal imaging that was determined to be a purely venous malformation on postnatal evaluation. This large malformation resulted in consumptive coagulopathy and apneic episodes from brainstem compression. The patient in Case 1 was treated initially with endovascular embolization and eventually with curative percutaneous-transfontanelle embolization. The patient in Case 2 was treated with percutaneous transfontanelle embolization in combination with posterior fossa decompression and cranial expansion surgery.

An institutional series and literature review of pial arteriovenous fistulas in the pediatric population: clinical article

OBJECT

Pial arteriovenous fistulas (PAVFs) are a rare form of cerebrovascular disease that tend to be overrepresented in the pediatric population. There have been limited studies of the clinical features and outcomes in this group of patients. Here, the authors attempt to better delineate this clinical entity with institutional cases and a review of the literature.

METHODS

A retrospective review of cases at our institution was performed to identify all pediatric patients treated for a PAVF between 2000 and 2012.

RESULTS

Five patients treated for a PAVF were identified. Patients had a mean age of 1.9 years at diagnosis, and the most common presenting symptoms were seizure and macrocephaly. Patients were treated primarily with embolization, and 3 patients required both N-butyl cyanoacrylate (NBCA) glue and coiling. Four of the patients had complete obliteration of the PAVF and had a pediatric overall performance category score of either 1 (n = 3) or 2 (n = 1) at follow-up. There was 1 death due to heart failure. Analysis of the literature review suggested that a younger age or presence of intracerebral hemorrhage (ICH) or congestive heart failure (CHF) at presentation likely predicts a worse prognosis. Older patients presented more often with ICH, whereas younger patients presented significantly more often in CHF. The majority of pediatric patients reported on in the literature were treated with endovascular embolization, most commonly with NBCA glue alone. Most patients (65.4%) in the literature had an excellent outcome without neurological deficit.

CONCLUSIONS

Pial AVFs represent a serious yet rare form of cerebrovascular disease. Pediatric patients with ICH or CHF at presentation or those who are very young are likely to have a worse prognosis. Endovascular management of these patients has greatly changed the natural history of this disease, but the complication and mortality rates suggest the need for continued insights and advances in treatment.

Spinal Pial (Type IV) Arteriovenous Fistulae

BACKGROUND:

Demographics, hemorrhage risk, and results of surgical and endovascular treatment of spinal pial (type IV) arteriovenous fistulae (AVFs) across a large patient group have not been previously reported.

OBJECTIVE:

To report demographics, hemorrhage rates, and treatment results for these AVFs.

METHODS:

We performed a pooled analysis via the PubMed and Embase databases through November 2012. Individualized patient data were extracted and analyzed using Cox proportional hazards regression to obtain hazard ratios for hemorrhage risk factors and pooled for baseline demographics and treatment results.

RESULTS:

We extracted information on 213 patients from 28 studies. Only 1% of lesions were incidental; 93% of patients presented with neurologic deficits and 36% with hemorrhage. Patients with type IVa lesions were significantly older (mean age, 46.9 years) and demonstrated a male sex predilection (68% male). Patients with type IVc lesions were significantly younger (mean age, 18.7 years), had no sex predilection, and had the highest prevalence of syndromic conditions (29% of cases). The annual hemorrhage rate was 2.5% (95% confidence interval [CI]: 1.4%-4.7%), increasing to 5.6% for hemorrhagic fistulae (95% CI: 3.0%-10.7%; hazard ratio: 6.31; 95% CI: 0.69-57.4; P = .10). Patient sex, fistula location, and fistula subclass were not significant risk factors for hemorrhage. The surgical obliteration rate was 88%; 68% of patients improved, 26% were the same, and 6% were worse. The endovascular obliteration rate was 74%; 75% of patients improved, 14% were the same, and 11% were worse.

CONCLUSION:

We demonstrate the utility of the Anson-Spetzler a-c subclassification and underscore the efficacy of surgical and endovascular spinal AVF treatment.

Addressing challenges in 4 F and 5 F arterial access for neurointerventional procedures in infants and young children

BACKGROUND

Among the technical challenges involved in safely performing neuroendovascular procedures in infants are limitations on the size of femoral arterial access catheters. Restricting groin access to 4 F and 5 F systems constrains the range of procedures that can potentially be performed.

METHODS AND RESULTS

We present here a consecutive series of transfemoral angiographic procedures in children with no permanent and one transient case of groin morbidity related to femoral access. We illustrate two strategies for using 4 F and 5 F systems for interventions in a manner that enables such techniques as balloon assisted coil embolization and the deployment of triaxial catheter systems to be used.

CONCLUSIONS

Extremely low groin morbidity is achievable using rigorous parameters around femoral catheterization in children. With creative approaches to working within the limitations of the access vessel size, complex endovascular neurointerventions are possible, even in the youngest infants.

Endovascular management of sigmoid sinus dural arteriovenous fistula associated with sinus stenosis in an infant

A 4-month-old female presented with a dural arteriovenous fistula (DAVF), which was successfully managed using endovascular techniques. There are very few case series reporting DAVF in infants younger than 12 months and, to our knowledge, only 60 pediatric patients with DAVF have been reported to date. Although most DAVF have a benign course, they can result in life-threatening hemorrhage. Endovascular therapies are usually indicated in the management of these neurosurgical vascular malformations. Endovascular therapy of DAVF in neonatal patients presents some major issues. Gaining arterial access may be problematic in femoral arteries too small for the introduction of a sizeable guiding catheter. The volumes of contrast and infused fluids must be carefully monitored to prevent fluid overload. Radiation exposure should be restricted as far as possible. This report contributes to the limited body of evidence on neonatal DAVF and its endovascular management.

The "Shaken Baby" syndrome: pathology and mechanisms

The "Shaken Baby" syndrome (SBS) is the subject of intense controversy; the diagnosis has in the past depended on the triad of subdural haemorrhage (SDH), retinal haemorrhage and encephalopathy. While there is no doubt that infants do suffer abusive injury at the hands of their carers and that impact can cause catastrophic intracranial damage, research has repeatedly undermined the hypothesis that shaking per se can cause this triad. The term non-accidental head injury has therefore been widely adopted. This review will focus on the pathology and mechanisms of the three physiologically associated findings which constitute the "triad" and are seen in infants suffering from a wide range of non-traumatic as well as traumatic conditions. "Sub" dural bleeding in fact originates within the deep layers of the dura. The potential sources of SDH include: the bridging veins, small vessels within the dura itself, a granulating haemorrhagic membrane and ruptured intracranial aneurysm. Most neuropathologists do not routinely examine eyes, but the significance of this second arm of the triad in the diagnosis of Shaken Baby syndrome is such that it merits consideration in the context of this review. While retinal haemorrhage can be seen clinically, dural and subarachnoid optic nerve sheath haemorrhage is usually seen exclusively by the pathologist and only rarely described by the neuroradiologist. The term encephalopathy is used loosely in the context of SBS. It may encompass anything from vomiting, irritability, feeding difficulties or floppiness to seizures, apnoea and fulminant brain swelling. The spectrum of brain pathology associated with retinal and subdural bleeding from a variety of causes is described. The most important cerebral pathology is swelling and hypoxic-ischaemic injury. Mechanical shearing injury is rare and contusions, the hallmark of adult traumatic brain damage, are vanishingly rare in infants under 1 year of age. Clefts and haemorrhages in the immediate subcortical white matter have been assumed to be due to trauma but factors specific to this age group offer other explanations. Finally, examples of the most common causes of the triad encountered in clinical diagnostic and forensic practice are briefly annotated.

Case series of atypical high flow arterio-venous malformations in children

Arteriovenous malformations (AVM) constitute a clinically significant form of vascular malformations in children. We present three cases of paediatric AVMs that demonstrated unusual features of high flow and significant shunting of blood without a clearly demonstrable nidus. Venous malformations were associated with the lesions. A discussion of the concepts underlying AVM physiology and how these case reports contradict these is included.