Management of Choroid Plexus Tumors and the Benefit of Preoperative Embolization in Pediatric Patients: Report of 46 Cases from a Single Institution.

OBJECTIVE: Optimal choroid plexus tumor (CPT) treatment involves gross total resection; however, intraoperative hemorrhage risk remains significant given tumor vascularity. This study describes pediatric CPT management and identifies patients most likely to benefit from preoperative embolization. METHODS: CPTs resected from 1997 to 2021 were included. The characteristics of embolized patients were compared to nonembolized patients; nonembolized patients were further stratified based on open vascular control-pedicle feeder ligation versus no pedicle ligation prior to tumor debulking. Statistical analyses identified factors associated with estimated blood loss (EBL), transfusion, length of stay, and complications. RESULTS: Among the 46 CPT cases identified, 98% achieved gross total resection, and 15% received embolization. Embolized patients were younger, smaller, and had larger tumors compared to nonembolized patients (median: 0.8 vs. 2.1 years; 9.3 vs. 14.4 kg; 91.08 vs. 5.5 cm3). Transfused patients were similarly younger and smaller (P < 0.05) than nontransfused patients. Among nonembolized patients, open vascular control was achieved in smaller tumors (<13 cm3) with significantly lower EBL (P = 0.002). Higher EBL was observed in patients with larger tumors, hydrocephalus, transependymal edema, vomiting, lethargy, and developmental regression (all P < 0.05). Patients with lethargy had longer hospital stays and a higher likelihood of postoperative complications (P < 0.05). There were no significant differences in complication rates between the embolization and nonembolization groups. CONCLUSIONS: Despite higher surgical risk profiles, embolized patients had similar complication rates and postoperative hydrocephalus management as nonembolized patients. Embolization was particularly beneficial in patients at high risk for surgical morbidity, such as those <2 years, weighing <10 kg, and with a tumor volume >15 cm3.

Morning glory disc anomaly and its implications in moyamoya arteriopathy: a retrospective case series.

OBJECTIVE: Morning glory disc anomaly (MGDA), a congenital abnormality of the optic nerve, may be associated with moyamoya arteriopathy, a cerebrovascular abnormality. In this study, the authors aimed to define the temporal evolution of cerebrovascular arteriopathy in patients with MGDA to characterize a rational strategy for screening and management over time. METHODS: The records of pediatric neurosurgical patients at two academic institutions were retrospectively reviewed to identify cases of cerebral arteriopathy and MGDA, including radiographic and clinical records documenting patient outcomes of medical and surgical management. RESULTS: Thirteen cases of moyamoya syndrome (MMS) associated with MGDA were identified in 13 children aged 0.6-17 years. The pattern of arteriopathy resembled that of non-MGDA MMS, with predominantly anterior circulation involvement. The arteriopathy lateralized with the MGDA, although 3 patients also had contralateral involvement. The overall group was followed for a median of 3.2 years. Radiological biomarkers of cerebral ischemia were applied to guide surgical decisions, and more than half of the patients (7 of 13) had evidence of stroke or progression on serial imaging. Nine patients underwent revascularization surgery, and 4 were managed medically. CONCLUSIONS: Cerebral arteriopathy observed in association with MGDA resembles MMS seen in patients without MGDA and is dynamic, with progression observed over months to years and an associated risk of cerebral ischemia that indicates a role for surgical revascularization. Radiological biomarkers may augment clinical data to identify candidates for revascularization surgery.

External validation of the R2eD AVM scoring system to assess rupture risk in pediatric AVM patients.

OBJECTIVE: The assessment of hemorrhagic risk is of central importance in the management of pediatric brain arteriovenous malformations (AVMs). A recently published scoring system, the R2eD AVM (race, exclusive deep location or not, AVM size < 3 or ≥ 3, venous drainage exclusively deep or not, and monoarterial feeding or >1 arterial feeders) considers patient race and AVM location, size, venous drainage, and arterial supply and was successfully externally validated for use in adults to predict the risk of AVM hemorrhagic presentation. In this study the authors sought to externally validate the R2eD AVM score for prediction of hemorrhagic risk in the pediatric AVM population. METHODS: A pediatric database at Boston Children's Hospital was retrospectively reviewed for all patients with a diagnosis of intracranial AVM. Exclusion criteria included age > 21 years, multiple AVMs, and incomplete clinical/radiographic data. Demographic data and R2eD AVM score calculations were collected for all patients. Univariate binary logistic regression and multivariate stepwise backward elimination models were used to determine factors associated with hemorrhagic presentation. RESULTS: A total of 212 AVMs were identified in 212 patients with vascular anomalies from 1995 to 2021, and 144 patients met the inclusion criteria (74 [51.4%] male, 111 [77.1%] White), of whom 87 (60.4%) patients presented with rupture and 122 (84.7%) underwent resection. The mean age at surgery was 12 years (range 3 months to 20 years). The R2eD AVM scoring system was applied to each patient. The score components of size < 3 cm and exclusive deep venous drainage were significantly associated with rupture risk (p < 0.05). The complete model for the R2eD AVM score had an area under the curve of 0.671 (95% CI 0.586-0.757). CONCLUSIONS: This study demonstrated poor external validity of the R2eD AVM score in predicting pediatric AVM rupture risk. The results suggest that future studies are warranted to determine a better scoring method to capture pediatric rupture risk, given the significant differences in clinical presentation in pediatric compared with adult AVM patients.

Optic nerve compression in craniopharyngioma by taut anterior cerebral arteries visualized in frontal and transsphenoidal exposures: illustrative cases.

BACKGROUND: During initial exposure and removal of craniopharyngioma in pediatric patients with severe visual field deficits, the authors have encountered severe deformation of the optic apparatus by taut anterior cerebral arteries as seen during both frontal craniotomy and transsphenoidal exposures. OBSERVATIONS: The authors report two pediatric patients with craniopharyngioma whose severe preoperative visual deficits were associated not only with large suprasellar masses but also with severe optic nerve and chiasm compression by taut anterior cerebral arteries. In each patient, the optic nerves were partially cleft by these vessels' indenting them. LESSONS: The role of a taut anterior cerebral artery complex in compression of the optic apparatus in patients with suprasellar tumors has been reported previously, but the intraoperative images in these two cases dramatically reveal this phenomenon.

Resolution of Primary or Recalcitrant Chiari-Associated Syringomyelia Requires Adequate Cerebrospinal Fluid Egress from the Fourth Ventricle.

Syringomyelia is often resistant to various treatment modalities.1 Chiari I malformations are associated with syringomyelia in approximately 69% of operative cases.2 Failure to resolve syringomyelia after Chiari decompression is common.3 The pathophysiology of Chiari-associated syringomyelia has been well studied, with Oldfield emphasizing the water-hammer mechanism, with treatment limited to bony decompression and duraplasty.4 On the other hand, capacious fourth ventricular drainage is thought to be essential for syrinx resolution. Persistence or progression of the syrinx after decompression is an indication for reoperation. Direct shunting of the syrinx is associated with high failure rates.1,5-7 The technique of shunting the fourth ventricle has been applied successfully in the pediatric population.3,8-10 We emphasize the need to ensure outflow from the fourth ventricle in Chiari decompressions associated with syringomyelia. In revisions to treat progressive syringomyelia after failed decompression, we undertake the following steps: 1) adequate lateral bony decompression,11-13 2) lysis of scar/adhesions around the cisterna magna, 3) opening the fourth ventricle outlet by releasing any web/adhesions, 4) insertion of a shunt from the fourth ventricle to the cervical subarachnoid space, and 5) bipolar coagulation of the lateral tonsillar pia to maintain patency of cerebrospinal fluid pathways.8 We favor autologous fascia or pericranium for expansile duraplasty, as the use of nonautologous materials may cause excessive scarring.14-16 In this video, we demonstrate these tenets in 3 cases of Chiari-associated syringomyelia, 2 revisions and 1 primary case, with excellent resolution of the syrinx (Video 1). The patients consented to surgery and publication of images.

Predictors of progression in radiation-induced versus nonradiation-induced pediatric meningiomas: a large single-institution surgical experience.

OBJECTIVE: The goal in this study was to outline unique differences between radiation-induced and nonradiation-induced pediatric meningiomas and to identify independent risk factors of tumor recurrence/progression. METHODS: This is a retrospective cohort study of all pediatric meningiomas diagnosed and surgically treated at the authors' institution between 1993 and 2017. Multivariable Cox regression was applied to identify independent risk factors for tumor recurrence/progression. RESULTS: Thirty-five patients were identified. The primary etiology was nonradiation-induced (n = 24: n = 3 with neurofibromatosis type 2) or radiation-induced (n = 11: acute lymphoblastic leukemia [n = 5], medulloblastoma [n = 4], germ cell tumor [n = 1], and primitive neuroectodermal tumor [n = 1]) meningioma. The mean age at time of diagnosis was 10.7 ± 5.7 years for nonradiation-induced and 17.3 ± 3.5 years for radiation-induced meningiomas. Overall, 8/24 patients with nonradiation-induced meningioma experienced either recurrence or progression of the tumor. Of the 8 patients with tumor recurrence or progression, the pathological diagnosis was clear cell meningioma (n = 3: 2 recurrent and 1 progressive); grade I (n = 2 progressive); grade I with atypical features (n = 2: 1 recurrent and 1 progressive); or atypical meningioma (n = 1 recurrent). None of the patients with radiation-induced meningioma experienced recurrence or progression. Predictors of tumor recurrence/progression by univariate analysis included age at time of diagnosis ≤ 10 years (p = 0.002), histological subtype clear cell meningioma (p = 0.003), and primary etiology nonradiation-induced meningioma (p = 0.04), and there was a notable trend with elevated MIB-1 staining index (SI) (p = 0.09). There was no significant difference between nonradiation-induced and radiation-induced meningiomas (p = 0.258), although there was a trend between recurrent and nonrecurrent meningiomas (p = 0.09). Multivariate Cox regression, adjusted for length of follow-up, identified younger age at diagnosis (p = 0.004) and a higher MIB-1 SI (p = 0.044) as independent risk factors for recurrence. Elevated MIB-1 SI statistically correlated with atypia (p < 0.001). However, there was no significant statistical correlation between tumor recurrence/progression and atypia (p = 0.2). CONCLUSIONS: Younger patient age and higher MIB-1 SI are independent risk factors for recurrence. Atypia was not a predictor of recurrence.

Late morbidity and mortality following revascularization surgery for moyamoya disease in the pediatric population.

OBJECTIVE: There are limited reports on long-term morbidity in pediatric patients who have undergone surgical revascularization for moyamoya disease (MMD). Here, the authors report long-term morbidity and mortality in a population of pediatric patients who underwent pial synangiosis for MMD from 1988 through 2016. METHODS: A single-center retrospective review of the hospital and personal operative databases of the senior authors was carried out to identify all patients who were treated for MMD at Boston Children's Hospital between 1988 and 2016, and who experienced any episode of late morbidity or mortality, which the authors defined as an event resulting in significant neurological deficit or death occurring more than 1 year after revascularization surgery. Hospital records were reviewed to determine pertinent demographic data, the initial mode of patient presentation, and associated comorbidities. Radiographic studies, when available, were reviewed for documentation of the diagnosis and for confirmation of the late complication, and the literature on this topic was reviewed. RESULTS: In total, 460 patients with MMD underwent surgery between 1988 and 2016 using the pial synangiosis surgical technique; 15 (3.3%) of these patients (9 females and 6 males) experienced documented late death (n = 14) or severe morbidity (n = 1). The median age at revascularization surgery was 8.0 years (range 1-21 years). The causes of these late complications were grouped into three etiologies: intraventricular or intracerebral hemorrhage (n = 8), systemic complications related to associated comorbidities or preoperative disabilities (n = 5), and the development of malignant brain tumors (n = 2). Four patients whose MMD was associated with a history of cranial radiation therapy died. These events occurred from as early as 2 years to as late as 27 years postoperatively. CONCLUSIONS: The risk of late morbidities and mortality following pial synangiosis for MMD in the pediatric patient appeared to be low. Nevertheless, the occurrence of catastrophic cerebrovascular events, particularly intracerebral and intraventricular hemorrhage in the otherwise neurologically stable revascularized patient, was concerning. Although there is value in long-term surveillance of patients who have undergone surgery for MMD, from both a neurological and a general medical standpoint, particularly in patients with the risk factor of prior cranial radiation therapy, it is not clear from the data how the late deaths in this population could have been prevented.

Management strategies for recurrent pediatric craniopharyngioma: new recommendations.

OBJECTIVE: The goal of this study was to identify the independent risk factors for recurrence or progression of pediatric craniopharyngioma and to establish predictors of the appropriate timing of intervention and best management strategy in the setting of recurrence/progression, with the aim of optimizing tumor control. METHODS: This is a retrospective cohort study of all pediatric patients with craniopharyngioma who were diagnosed and treated at Boston Children's Hospital between 1990 and 2017. This study was approved by the institutional review board at Boston Children's Hospital. All statistical analyses were performed using Stata software. RESULTS: Eighty patients (43 males and 37 females) fulfilled the inclusion criteria. The mean age at the time of diagnosis was 8.6 ± 4.4 years (range 1.2-19.7 years). The mean follow-up was 10.9 ± 6.5 years (range 1.3-24.6 years). Overall, 30/80 (37.5%) patients developed recurrence/progression. The median latency to recurrence/progression was 12.75 months (range 3-108 months). Subtotal resection with no adjuvant radiotherapy (p < 0.001) and fine calcifications (p = 0.008) are independent risk factors for recurrence/progression. An increase (%) in the maximum dimension of the tumor at the time of recurrence/progression was considered a statistically significant predictor of the appropriate timing of intervention. CONCLUSIONS: Based on the identified independent risk factors for tumor recurrence/progression and the predictors of appropriate timing of intervention in the setting of recurrence/progression, the authors propose an algorithm for optimal management of recurrent pediatric craniopharyngioma to increase the likelihood of tumor control.

Novel predictive scoring system for morbid hypothalamic obesity in patients with pediatric craniopharyngioma.

PURPOSE: To identify the independent risk factors for developing morbid hypothalamic obesity, to propose a predictive scoring system for morbid hypothalamic obesity, and to propose an algorithm for management in order to minimize the risk of developing morbid hypothalamic obesity in patients with pediatric craniopharyngioma. METHODS: A retrospective analysis of all pediatric craniopharyngioma patients diagnosed and treated at Boston Children's Hospital (BCH) between 1985 and 2017. Analysis of the data was conducted using IBM SPSS Statistics. RESULTS: We identified 105 patients, 90 (47 males and 43 females) fulfilled the inclusion criteria. The median age of patients at time of diagnosis was 8.4 years. The median follow-up was 10.6 years. Morbid hypothalamic obesity was evident in 28 (31.1%) patients at the last follow-up visit. Age of patients at time of diagnosis > 10 years (P = 0.023), preoperative body mass index (BMI) > 95th percentile (P = 0.006), and preoperative papilledema (P < 0.001) were the independent risk factors for developing morbid hypothalamic obesity. CONCLUSION: We developed a unique predictive scoring system in order to differentiate between patients with and without high risk for developing morbid hypothalamic obesity.

Postoperative MR imaging surveillance of pediatric craniopharyngioma: new institutional guidelines.

PURPOSE: To develop postoperative surveillance protocols that yield efficient detection rates of tumor recurrence or progression using fewer imaging studies and less cost. METHOD: This is a retrospective cohort study of all pediatric craniopharyngioma patients who have been diagnosed and treated at Boston Children's Hospital (BCH) between 1990 and 2017. All statistical analyses were performed using Stata. RESULTS: Eighty patients (43 males and 37 females) fulfilled the inclusion criteria. The mean age at time of diagnosis was 8.6 ± 4.4 years. The mean follow-up period was 10.9 ± 6.5 years. Overall 30/80 (37.5%) patients experienced tumor recurrence/progression. The median latency to recurrence/progression was 12.75 months (range 3 to 108 months), with 76.6% of the recurrences/progressions taking place within the first 2 years postoperatively. Given the lack of any clinical symptoms/signs associated with the vast majority of the recurrent/progressed cases, we propose postoperative MR imaging surveillance protocols that are substantially less intensive than the current practice. Therefore, we recommend the following postoperative MR imaging surveillance protocols, stratified by management strategies; 0, 9, 15, 36, 48, and 60 months for patients who underwent GTR, 0, 3, 6,12, 18, and 24 months for patients who underwent STR alone and 0, 3, 12, 72, 96, and 120 months for patients who underwent STR followed by subsequent XRT. CONCLUSION: The proposed postoperative MR imaging surveillance protocols would provide a potential 50% decrement of healthcare costs. It may also minify the psychological burden of frequent MR scanning for these patients and their families.

Long-term stability of fusiform dilatation of the internal carotid artery following surgery adjacent to the circle of Willis: report of 2 cases.

Fusiform dilatation of the internal carotid artery (FDCA) is a known postoperative imaging finding after craniopharyngioma resection. FDCA has also been reported following surgery for other lesions in the suprasellar region in pediatric patients and is thought to be due to trauma to the internal carotid artery (ICA) wall during tumor dissection. Here, the authors report 2 cases of pediatric patients with FDCA. Case 1 is a patient in whom FDCA was visualized on follow-up scans after total resection of a craniopharyngioma; this patient's subsequent scans and neurological status remained stable throughout a 20-year follow-up period. In case 2, FDCA appeared after resection and fenestration of a giant arachnoid cyst in a 3-year-old child, with 6 years of stable subsequent follow-up, an imaging finding that to the authors' knowledge has not previously been reported following surgery for arachnoid cyst fenestration. These cases demonstrate that surgery involving dissection adjacent to the carotid artery wall in pediatric patients may lead to the development of FDCA. On very long-term follow-up, this imaging finding rarely changes and virtually all patients remain asymptomatic. Neurointerventional treatment of FDCA in the absence of symptoms or significant late enlargement of the arterial ectasia does not appear to be indicated.

Central retinal artery occlusion occurring 30 years after successful revascularization surgery for moyamoya disease: case report.

We report a case of central retinal artery occlusion (CRAO) leading to unilateral blindness occurring in a moyamoya patient 30 years after successful pial synangiosis when she was 6 years old. Imaging studies at the time of the CRAO revealed total occlusion of the ipsilateral cervical and intracranial internal carotid artery, a vessel shown to be patent on MRI/MRA studies for decades previously. This case demonstrates that long-term follow-up of operated moyamoya patients may reveal late secondary complications, of which physicians, patients, and families need to be aware.

Surgical volume of simple tethered spinal cord releases: review of a large pediatric neurosurgical service experience.

OBJECTIVE: The aim of this study was to retrospectively review, from a single busy pediatric neurosurgical service, a consecutive series of patients who had undergone surgery for a simple tethered spinal cord, which was defined by a thickened or fatty filum terminale with a normal conus. The hope was to contribute to benchmark data regarding the expected frequency of surgery for this condition. METHODS: The authors reviewed the electronic medical records of every patient with diagnosed simple tethered spinal cord, defined on spinal MRI as a thickened (> 2 mm in diameter) or fatty filum terminale, and who had undergone primary filum section at Boston Children's Hospital between 2005 and 2011. RESULTS: A total of 208 patients met the study inclusion criteria. At the time of surgery, patients ranged in age from 0.4 to 19.8 years. One hundred forty-four (69%) patients were symptomatic with one or more of the following: bowel/bladder dysfunction, 94 (45%); neurological dysfunction, 49 (24%); scoliosis, 44 (21%); or back pain, 44 (21%). Sixty-four (31%) patients were asymptomatic and were operated on prophylactically when filum pathology was discovered during the course of a workup for clinical syndromes such as anorectal anomalies and/or suspicious cutaneous lesions. No patients in this series were operated on if they had normal MRI studies, defined as a conus tip no lower than L3 and no distal tethering lesion visualized. Over the study period, approximately 1000 major surgical cases were performed in the department every year, only 30 of which were simple detethering procedures, representing well under 5% of the service's operative volume and approximately 5 cases per surgeon per year. Clinical follow-up, available at a postoperative interval of 6.6 ± 3.8 years, demonstrated that approximately 80% of patients symptomatic with bowel or bladder involvement or neurological dysfunction had improvement or relief of their symptoms and that none of the patients treated prophylactically experienced new-onset symptoms that could be related to spinal tethering. CONCLUSIONS: Simple detethering procedures were relatively uncommon in an active, well-established pediatric neurosurgical service and represented less than 5% of the service's total case volume per year with an average of 5 cases per surgeon per year. No patients with normal MRI studies were operated on during the study period.

Pediatric neurosurgery training during residency in the United States: a program director survey.

OBJECTIVE: Pediatric neurosurgery is a core component of neurosurgical residency training. Pediatric case minimums are established by the Neurosurgery Residency Review Committee of the Accreditation Council for Graduate Medical Education (ACGME). Case minimums, by themselves, allow for great variability in training between programs. There are no prior data on how the residency programs meet these requirements. The authors' objective was to gather information on pediatric neurosurgical education among the ACGME-accredited neurosurgery training programs in order to shape further pediatric neurosurgical educational efforts. METHODS: A 25-question survey about pediatric neurosurgical education was created by the Education Committee of the Section on Pediatric Neurological Surgery of the American Association of Neurological Surgeons/Congress of Neurological Surgeons and distributed to program directors of all 111 ACGME-accredited neurosurgery training programs. RESULTS: The response rate was 77% (86/111). In 55% of programs the residents are rotated to a responder-designated "freestanding" children's hospital, and 39% of programs rotate residents to a children's hospital within a larger adult hospital or a general hospital. There are 4 or fewer pediatric neurosurgical faculty in 91% of programs. In 12% of programs less than 100 cases are performed per year, and in 45% more than 500 are performed. In 31% of responding neurosurgery residency programs there is also a pediatric neurosurgery fellowship program supported by the same sponsoring institution. Seventy-seven percent of programs have at least one specific pediatric neurosurgery rotation, with 71% of those rotations occurring during postgraduate year 3 and 50% occurring during postgraduate year 4. The duration of pediatric rotation varies from no specific rotation to more than 1 year, with 48% of residents spending 4-6 months on a pediatric rotation and 12% spending 7-11 months. Last, 17% of programs send their residents to external sites sponsoring other residency programs for their pediatric rotation. CONCLUSIONS: There is great variety between neurosurgery training programs with regard to resident education in pediatric neurosurgery. This study's data will serve as a baseline for future studies, and the authors hope the findings will guide further efforts in pediatric neurosurgical education in residency training programs.

Sixty years single institutional experience with pediatric craniopharyngioma: between the past and the future.

PURPOSE: To demonstrate the paradigm shift in management strategies of pediatric craniopharyngioma at our institution over the past six decades. METHODS: Retrospective analysis of all pediatric patients with craniopharyngioma treated at Boston Children's Hospital between 1960 and 2017. RESULTS: One hundred seventy-eight patients with craniopharyngioma were treated between 1960 and 2017; 135 (70 males and 65 females) fulfilled the inclusion criteria. Forty-five patients were treated in the old era (1960-1984) and 90 patients were treated in the new era (1985-2017). Gross total resection (GTR) was achieved in 4% and 43% of patients in old and new eras respectively. Sub-total resection (STR) and radiotherapy (XRT) were performed in 27% and 28% of patients in old and new eras respectively. STR without XRT was performed in 20% and 29% of patients in old and new era respectively. Cyst drainage and adjuvant radiotherapy were performed in 49% of patients in the old era while no patients in the new era underwent such conservative management. Aggressive surgical resection was associated with a higher risk of worsening visual outcomes (20% vs 16%), panhypopituitarism and diabetes insipidus (86% vs 53%), psycho-social impairment (42% vs 26%), and new-onset obesity (33% vs 22%). The mortality rate was higher in the old era in comparison with that of the new one (9% vs 2%). CONCLUSION: There was a paradigm shift in management strategies of pediatric craniopharyngioma over the past six decades which in turn affected the long-term outcomes and quality of life of patients.

The utility of intraoperative MRI during pediatric brain tumor surgery: a single-surgeon case series.

OBJECTIVE: The authors sought to evaluate the utility of intraoperative MRI (ioMRI) during brain tumor excision in pediatric patients and to suggest guidelines for its future use. METHODS: All patients who underwent brain tumor surgery by the senior author at Boston Children's Hospital using ioMRI between 2005 and 2009 were included in this retrospective review of hospital records and the neurosurgeon's operative database. Prior to the review, the authors defined the utility of ioMRI into useful and not useful categories based on how the technology affected operative management. They determined that ioMRI was useful if it 1) effectively guided the extent of resection; 2) provided a baseline postoperative scan during the same anesthesia session; or 3) demonstrated or helped to prevent an intraoperative complication. The authors determined that ioMRI was not useful if 1) the anatomical location of the tumor had precluded a tumor's total resection, even though the surgeon had employed ioMRI for that purpose; 2) the tumor's imaging characteristics prevented an accurate assessment of resection during intraoperative imaging; 3) the surgeon deemed the technology not required for tumor resection; or 4) the intraoperative MR images were uninterpretable for technical reasons. Follow-up data provided another gauge of the long-term benefit of ioMRI to the patient. RESULTS: A total of 53 brain tumor patients were operated on using ioMRI, 6 of whom had a second ioMRI procedure during the study period. Twenty-six patients were female, and 27 were male. The mean follow-up was 4.8 ± 3.85 years (range 0-12 years). By the criteria outlined above, ioMRI technology was useful in 38 (64.4%) of the 59 cases, most frequently for its help in assessing extent of resection. CONCLUSIONS: Intraoperative MRI technology was useful in the majority of brain tumor resections in this series, especially in those tumors that were contrast enhancing and located largely within accessible areas of the brain. The percentage of patients for whom ioMRI is useful could be increased by preoperatively evaluating the tumor's imaging characteristics to determine if ioMRI would accurately assess the extent of tumor resection, and by the surgeon's preoperative understanding that use of the ioMRI will not lead to resection of an anatomically unresectable tumor. The ioMRI can prove useful in unresectable tumors if specific operative goals are defined preoperatively.

A national analysis of 9655 pediatric cerebrovascular malformations: effect of hospital volume on outcomes.

OBJECTIVE: Comprehensive multicenter data on the surgical treatment of pediatric cerebrovascular malformations (CVMs) in the US are lacking. The goal of this study was to identify national trends in patient demographics and assess the effect of hospital case volume on outcomes. METHODS: Admissions for CVMs (1997-2012) were identified from the nationwide Kids' Inpatient Database. Admissions with and without craniotomy were reviewed separately. Patients were categorized by whether they were treated at low-, medium-, or high-volume centers (< 10, 10-40, > 40 cases/year, respectively). A generalized linear model was used to evaluate the association of hospital pediatric CVM case volume and clinical variables assessing outcomes. RESULTS: Among the 9655 patients, 1828 underwent craniotomy and 7827 did not. Patient age and race differed in the two groups, as did the rate of private medical payers. High-volume hospitals had fewer nonroutine discharges (11.2% [high] vs 16.4% [medium] vs 22.3% [low], p = 0.0001). For admissions requiring craniotomy, total charges ($106,282 [high] vs $126,215 [medium] vs $134,978 [low], p < 0.001) and complication rates (0.09% [high] vs 0.11% [medium] vs 0.16% [low], p = 0.001) were lower in high-volume centers. CONCLUSIONS: This study revealed that further investigation may be needed regarding barriers to surgical treatment of pediatric CVMs. The authors found that surgical treatment of pediatric CVM at high-volume centers is associated with significantly fewer complications, better dispositions, and lower costs, but for noncraniotomy patients, low-volume centers had lower rates of complications and death and lower costs. These findings may support the consideration of appropriate referral of CVM patients requiring surgery or with intracranial hemorrhage toward high-volume, specialized centers.

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

OBJECTIVE: Large experiences with the treatment of pediatric arteriovenous malformations (AVMs) remain relatively rare, with limited data on presentation, treatment, and long-term functional outcomes. Because of the expected long lifespan of children, caregivers are especially interested in outcome measures that assess quality of life. The authors' intention was to describe the long-term functional outcomes of pediatric patients who undergo AVM surgery and to identify predictors of sustained neurological deficits. METHODS: The authors analyzed a 21-year retrospective cohort of pediatric patients with intracranial AVMs treated with microsurgery at two institutions. The primary outcome was a persistent neurological deficit at last follow-up. Secondary outcome measures included modified Rankin Scale (mRS) score and independent living. RESULTS: Overall, 97 patients (mean age 11.1 ± 4.5 years; 56% female) were treated surgically for intracranial AVMs (mean follow-up 77.5 months). Sixty-four patients (66%) presented with hemorrhage, and 45 patients (46%) had neurological deficits at presentation. Radiologically, 39% of lesions were Spetzler-Martin grade II. Thirty-seven patients (38%) with persistent neurological deficits at last follow-up were compared with those without deficits; there were no differences in patient age, presenting Glasgow Coma Scale score, AVM size, surgical blood loss, or duration of follow-up. Multivariate analysis demonstrated that a focal neurological deficit on presentation, AVM size > 3 cm, and lesions in eloquent cortex were independent predictors of persistent neurological deficits at long-term follow-up. Overall, 92% of the children had an mRS score ≤ 2 on long-term follow-up. CONCLUSIONS: Pediatric patients with AVMs treated with microsurgical resection have good functional and radiological outcomes. There is a high rate (38%) of persistent neurological deficits, which were independently predicted by preoperative deficits, AVMs > 3 cm, and lesions located in eloquent cortex. This information can be useful in counseling families on the likelihood of long-term neurological deficits after cerebral AVM surgery.

Results of more than 20 years of follow-up in pediatric patients with moyamoya disease undergoing pial synangiosis.

OBJECTIVEThere are limited data on the long-term outcomes for children undergoing surgical revascularization for moyamoya disease (MMD) in North America. The authors present a series of pediatric MMD patients who underwent a standard revascularization procedure, pial synangiosis, more than 20 years previously at a single institution by a single surgical team.METHODSThis study is a retrospective review of all patients aged 21 years or younger treated for MMD at Boston Children's Hospital who were operated on more than 20 years previously by the senior author (R.M.S.). Radiographic and operative reports, outpatient clinical records, and communications with patients and families were reviewed to document current clinical status, ability to perform daily activities, and concurrent or new medical conditions.RESULTSA total of 59 patients (38 female [64.4%], 21 male [35.6%]; median age at surgery 6.2 years [IQR 0.5-21 years]) were identified who were diagnosed with MMD and underwent surgical revascularization procedures more than 20 years previously. Clinically, all but 2 patients (96.6%) presented with the following symptoms alone or in combination: 43 (73%) presented with stroke, 22 (37%) with transient ischemic attack, 12 (20%) with seizures, 7 (12%) with headache, 3 (5%) with choreiform movements, and 2 (3%) with hemorrhage; MMD was incidentally detected in 2 patients (3%). Five patients had unilateral MMD at presentation, but 3 of these ultimately progressed to develop bilateral MMD after an average of 16 months; therefore, pial synangiosis was ultimately performed in a total of 116 hemispheres during the study period. Clinical follow-up was available at a median interval of 20.6 years (IQR 16.1-23.2 years). Modified Rankin Scale scores were stable or improved in 43 of 50 patients with evaluable data; 45 of 55 are currently independent. There were 6 patient deaths (10.2%; 3 due to intracranial hemorrhage, 2 due to tumor-related complications, and 1 due to pulmonary artery stenosis), 4 of whom had a history of previous cranial radiation. One patient (1.7%) experienced a late stroke. Synangiosis vessels remained patent on all available late MRI and MRA studies. Four patients reported uneventful pregnancies and vaginal deliveries years following their revascularization procedures.CONCLUSIONSRevascularization for MMD by pial synangiosis appears to confer protection from stroke for pediatric patients over long-term follow-up. A history of cranial radiation was present in 4 of the 5 patients who died and in the lone patient with late stroke. Most patients can expect productive, independent lives following revascularization surgery in the absence of significant preoperative neurological deficits and comorbidities.