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Alexandra D. Beier and Peter B. Dirks

Traumatic brain injuries afflict a large number of pediatric patients. The most severe injuries lead to increased intracranial pressure and herniation, with resultant changes in the brainstem. Traumatic brainstem hemorrhages have previously been associated with poor neurological outcome and fatality. However, this report discusses 2 pediatric patients who sustained severe head trauma with subsequent brainstem hemorrhages, and yet experienced good neurological outcome; the possible mechanism is described.

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Richard J. Edwards and Peter B. Dirks

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Michael J. Ellis, Derek Armstrong, and Peter B. Dirks

The management of large and giant arteriovenous malformations (AVMs) in patients presenting with nonhemorrhagic neurological deficits secondary to vascular steal phenomenon is challenging and controversial. In many cases, large AVMs cannot be completely excised or cured, leaving patients with residual or partially treated AVMs, the natural history of which is unknown. Additionally, large, diffuse vascular malformations with multiple, small feeders, slow flow, or so-called cerebral proliferative angiopathy represent a related but distinct clinical and angiographic entity that may require a different therapeutic approach than traditional brain AVMs. The current management of children with other conditions of chronic cerebral hypoperfusion, such as moyamoya disease, involves consideration of surgical revascularization to enhance blood flow to the compromised hemisphere. Here, the authors present the case of a young child with a large thalamic vascular malformation who presented with clinical and radiological features of vascular steal and ischemia. In an effort to augment flow to the hypoperfused brain and protect against future ischemia, the authors treated the child with unilateral pial synangiosis. At 12 months, postoperative angiography demonstrated robust neovascularization, and the child has not sustained any further ischemic events. The authors discuss concept of vascular malformation–related hypoperfusion and the utility of indirect revascularization for inoperable vascular malformations presenting with ischemic symptoms.

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Guillaume Saliou, Peter Dirks, Lee-Anne Slater, and Timo Krings

OBJECTIVE

The etiology of jugular bulb stenosis (JBS) or occlusion in the context of vein of Galen aneurysmal malformations (VGAMs) is unknown. It can lead to decompensation of a lesion that was previously clinically stable. The aim of this study was to describe the natural history of JBS or occlusion in VGAM and to determine whether there is an association with bony remodeling of the jugular foramina.

METHODS

The authors identified all cases of JBS greater than 70% bilaterally involving patients seen at The Hospital for Sick Children between January 2007 and June 2014. The foramen diameters were measured on sagittal CT imaging, on a slice passing at the level of the jugular vein. The jugular foramen diameters were also compared to measurements obtained in a matched population of the same age group who had no VGAM and had undergone cerebral CT for a reason other than vascular disease.

RESULTS

Eight patients (6 male and 2 female) with bilateral JBS were included in this series. The median duration of clinical follow-up was 2.5 years (IQR 1.7–4.2 years). JBS was associated with bony narrowing the jugular foramina in 7 of the 8 patients over time. Between 1 and 2 years of age, patients with a VGAM demonstrated jugular foramen narrowing in comparison with a matched population (p = 0.015).

CONCLUSIONS

Jugular bulb stenosis or occlusion in VGAM may be associated with narrowing of the jugular foramina. These conditions seem to have a male predominance. If treatment is required, bony narrowing of the jugular foramina should be taken into account when deciding whether angioplasty and stent placement or surgical bypass might be appropriate therapeutic options.

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Pieter Wesseling, Jeroen A. W. M. van der Laak, Henk de Leeuw, Dirk J. Ruiter, and Peter C. Burger

✓ Because histologically prominent microvascular proliferation is frequently present in glioblastoma multiforme, it has been hypothesized that this neoplasm is particularly dependent on neovascularization for its continued growth and that antiangiogenic therapy might be especially useful. To quantify the histological aspects of microvascular proliferation in glioma, a feasible and reproducible method was developed for computer-assisted image analysis of the visualized microvasculature in glial tissue. This method was used to compare several vascular parameters in histological whole-tumor sections of untreated human glioblastoma multiforme with those in histologically normal cerebral cortex and white matter. There was a significant increase in mean number, area, and perimeter of blood vessels per microscopic field in glioblastoma multiforme compared to normal cerebral white matter. In a substantial number of tumor fields, however, the vascular density was in the same range as that of normal cerebral white matter. The striking heterogeneity of the microvasculature within glioblastoma multiforme was illustrated by the significantly higher standard deviation for the vascular parameters in tumor tissue. The results of this study suggest that many regions of glioblastomas multiforme are not overtly angiogenesis dependent and may be difficult to treat by antiangiogenic therapy alone.

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Ratan D. Bhardwaj, Kurtis I. Auguste, Abhaya V. Kulkarni, Peter B. Dirks, James M. Drake, and James T. Rutka

Object

Because of their location and biological behavior, brainstem cavernous malformations (CMs) pose a formidable clinical challenge to the neurosurgeon. The optimal management of these lesions requires considerable neurosurgical judgment. Accordingly, the authors reviewed their experience with the management of pediatric brainstem CMs at the Hospital for Sick Children.

Methods

The authors performed a retrospective chart review of pediatric patients who had received diagnoses of a brainstem CM at the Hospital for Sick Children over the past 20 years.

Results

Twenty patients were diagnosed with brainstem CMs. The mean age at diagnosis was 10.1 ± 5.4 years, and the patients included 13 boys and 7 girls. The mean maximal diameter of the CM was 14.3 ± 11.2 mm. The lesions were evenly distributed on the right and left sides of the brainstem with 4 midbrain, 13 pontine, and 3 medullary lesions. Seven patients underwent surgery for the management of their CMs, with a mean age at presentation of 5.2 years, and a mean CM size of 21.0 mm. Of note from the surgical group, 2 patients had a family history of CMs, 2 lesions were medullary, the CM reached a pial surface in 6 of 7 patients, and 6 of 7 lesions were located on the right side. The mean age at presentation among the 13 patients in the nonsurgical group was 12.7 years, and the mean CM size was 10.6 mm. Seven of these patients had a prior history of radiation for tumor, and only 3 had lesions that reached a pial surface.

Conclusions

The management of brainstem CMs in children is influenced by multiple factors. The majority of patients received conservative management and tended to be asymptomatic with smaller lesions. Patients with larger lesions and direct pial contact, in whom symptoms arose at a younger age were more likely to undergo surgical management. A history of familial CM was also a predictor for receiving surgical treatment. No patients with a prior history of radiation therapy underwent surgery for CMs. The presence of multiple lesions seemed to have no impact on the type of management chosen. Patients who underwent surgery did suffer morbidity related to the procedure, and tended to improve clinically over time. Conservative management was associated with new deficits arising in children, some of which improved with time. Consideration of many clinical and radiological parameters is thus prudent when managing the care of children with brainstem CMs.

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Ibrahim Ahmed, Kurtis I. Auguste, Shobhan Vachhrajani, Peter B. Dirks, James M. Drake, and James T. Rutka

Object

Epidermoid tumors are benign lesions representing 1% of all intracranial tumors. There have been few pediatric series of intracranial epidermoid tumors reported previously. The authors present their experience in the management of these lesions.

Methods

The neurosurgical database at the Hospital for Sick Children was searched for children with surgically managed intracranial epidermoid tumors. The patients' charts were reviewed for demographic data, details of clinical presentation, surgical therapy, and follow-up. Ethics board approval was obtained for this study.

Results

Seven children, all girls, were identified who met the inclusion criteria between 1980 and 2007. The average age at surgery was 11.2 years (range 8–15 years), and the mean maximal tumor diameter was 2.1 cm. Headache was the most common presenting symptom, and 1 tumor was found incidentally. Most patients had normal neurological examinations, but meningism was found in 2 cases. There were 3 cerebellopontine angle lesions, 1 pontomedullary lesion, and 3 supratentorial tumors. Hydrocephalus developed in 1 patient after aseptic meningitis, and she underwent shunt placement. There were no operative deaths. Complete resection could be performed in 2 patients. One patient experienced a small recurrence that did not require a repeated operation, while 1 subtotally resected lesion recurred and the patient underwent a second operation.

Conclusions

Intracranial epidermoid tumors are rare in the pediatric population. Total resection is desirable to minimize the risk of postoperative aseptic meningitis, hydrocephalus, and tumor recurrence. Aggressive neurosurgical resection may be associated with cranial nerve or ischemic deficits, however. In these cases, neurosurgical judgment at the time of surgery is warranted to ensure maximum resection while minimizing postoperative neurological deficits.

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Ibrahim H. Al-Ahmed, Mohamed Boughamoura, Peter Dirks, Abhaya V. Kulkarni, James T. Rutka, and James M. Drake

Object

Neurenteric cysts (NCs) are endothelium-lined structures of presumed endodermal origin. There have been few pediatric series of intracranial NCs reported previously. The authors present their experience in the management of these lesions.

Methods

A retrospective chart review of all cases of NCs identified between 1977 and 2007 was carried out. Demographics, details of clinical presentation, surgical therapy, and outcome data were extracted.

Results

Eleven cases were identified, involving 6 girls and 5 boys. The patients' average age was 4.6 years (range 1 day–14 years). Limb weakness was the most common presenting symptom. The location of the cysts was cervical in 2 cases, cervicothoracic in 4 cases, and thoracic in 3 cases. One cyst was anterior to the pons with extension to the left cerebellopontine angle and 1 cyst was at the craniocervical junction. Five patients had an apparently complete initial excision, with 1 recurrence. Four patients were initially treated with incomplete excision and/or cyst drainage, usually into an Ommaya reservoir. A neonate with a large cervicothoracic cyst died of multiple congenital anomalies without any intervention. All other patients were alive at last follow-up. One patient with a radiologically identified presumed cyst, which remained stable, was simply followed up. Several patients required multiple procedures and 1 patient developed hydrocephalus after aseptic meningitis and was treated with CSF shunting.

Conclusions

Neurenteric cysts are rare in the pediatric population. Total resection, if possible, provides the best long-term outcome. Incomplete excision may lead to multiple procedures, including cyst drainage, but can lead to long-term stability.

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Daniel-Alexandre Bisson, Peter Dirks, Afsaneh Amirabadi, Manohar M. Shroff, Timo Krings, Vitor Mendes Pereira, and Prakash Muthusami

OBJECTIVE

There are little data in the literature on the characteristics and natural history of unruptured intracranial aneurysms in children. The authors analyzed their experience with unruptured intracranial aneurysms in the pediatric population at their tertiary care pediatric institution over the last 18 years. The first objective was to assess the imaging characteristics and natural history of these aneurysms in order to help guide management strategies in the future. A second objective was to evaluate the frequency of an underlying condition when an incidental intracranial aneurysm was detected in a child.

METHODS

The authors conducted a Research Ethics Board–approved retrospective review of incidental intracranial aneurysms in patients younger than 18 years of age who had been treated at their institution in the period from 1998 to 2016. Clinical (age, sex, syndrome) and radiological (aneurysm location, type, size, thrombus, mass effect) data were recorded. Follow-up imaging was assessed for temporal changes.

RESULTS

Sixty intracranial aneurysms occurred in 51 patients (36 males, 15 females) with a mean age of 10.5 ± 0.5 years (range 9 months–17 years). Forty-five patients (88.2%) had a single aneurysm, while 2 and 3 aneurysms were found in 3 patients each (5.8%). Syndromic association was found in 22 patients (43.1%), most frequently sickle cell disease (10/22 [45.5%]). Aneurysms were saccular in 43 cases (71.7%; mean size 5.0 ± 5.7 mm) and fusiform in the remaining 17 (28.3%; mean size 6.5 ± 2.7 mm). Thirty-one aneurysms (51.7%) arose from the internal carotid artery (right/left 1.4), most commonly in the cavernous segment (10/31 [32.3%]). Mean size change over the entire follow-up of 109 patient-years was a decrease of 0.6 ± 4.2 mm (range −30.0 to +4.0 mm, rate −0.12 ± 9.9 mm/yr). Interval growth (2.0 ± 1.0 mm) was seen in 8 aneurysms (13.3%; 4 saccular, 4 fusiform). An interval decrease in size (8.3 ± 10.7 mm) was seen in 6 aneurysms (10%). There was an inverse relationship between aneurysm size and growth rate (r = −0.82, p < 0.00001). One aneurysm was treated endovascularly with internal carotid artery sacrifice.

CONCLUSIONS

Unruptured pediatric intracranial aneurysms are most frequently single but can occur in multiples in a syndromic setting. None of the cases from the study period showed clinical or imaging signs of rupture. Growth over time, although unusual and slow, can occur in a proportion of these patients, who should be identified for short-term imaging surveillance.

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James T. Rutka, Masaji Murakami, Peter B. Dirks, Sherri Lynn Hubbard, Laurence E. Becker, Kozo Fukuyama, Shin Jung, and Kazuhito Matsuzawa

In the adult human brain, normal astrocytes constitute nearly 40% of the total central nervous system (CNS) cell population and may assume a star-shaped configuration resembling epithelial cells insofar as the astrocytes remain intimately associated, through their cytoplasmic extensions, with the basement membrane of the capillary endothelial cells and the basal lamina of the glial limitans externa. Although their exact function remains unknown, in the past, astrocytes were thought to subserve an important supportive role for neurons, providing a favorable ionic environment, modulating extracellular levels of neurotransmitters, and serving as spacers that organize neurons. In immunohistochemical preparations, normal, reactive, and neoplastic astrocytes may be positively identified and distinguished from other CNS cell types by the expression of the astrocyte-specific intermediate filament glial fibrillary acidic protein (GFAP). This GFAP is a 50-kD intracytoplasmic filamentous protein that constitutes a portion of, and is specific for, the cytoskeleton of the astrocyte. This protein has proved to be the most specific marker for cells of astrocytic origin under normal and pathological conditions. Interestingly, with increasing astrocytic malignancy, there is progressive loss of GFAP production. As the human gene for GFAP has now been cloned and sequenced, this review begins with a summary of the molecular biology of GFAP including the proven utility of the GFAP promoter in targeting genes of interest to the CNS in transgenic animals. Based on the data provided the authors argue cogently for an expanded role of GFAP in complex cellular events such as cytoskeletal reorganization, maintenance of myelination, cell adhesion, and signaling pathways. As such, GFAP may not represent a mere mechanical integrator of cellular space, as has been previously thought. Rather, GFAP may provide docking sites for important kinases that recognize key cellular substrates that enable GFAP to form a dynamic continuum with microfilaments, integrin receptors, and the extracellular matrix.