Underutilization of advanced presurgical studies and high rates of vagus nerve stimulation for drug-resistant epilepsy: a single-center experience and recommendations.

INTRODUCTION: Epilepsy surgery continues to be profoundly underutilized despite its safety and effectiveness. We sought to investigate factors that may contribute to this phenomenon, with a particular focus on the antecedent underutilization of appropriate preoperative studies. METHODS: We reviewed patient data from a pediatric epilepsy clinic over an 18-month period. Patients with drug-resistant epilepsy (DRE) were categorized according to brain magnetic resonance imaging (MRI) findings (lesional, MRI-negative, or multifocal abnormalities) and type of epilepsy diagnosis based on semiology and electroencephalography (EEG) (focal or generalized). We then analyzed the rates of diagnostic test utilization, surgical referral, and subsequent epilepsy surgery as well as vagus nerve stimulation (VNS). RESULTS: Of the 249 patients with a diagnosis of epilepsy, 138 (55.4%) were found to have DRE. Excluding the 10 patients with DRE who did not undergo MRI, 76 patients (59.4%) were found to be MRI-negative (non-lesional epilepsy), 37 patients (28.9%) were found to have multifocal abnormalities, and 15 patients (11.7%) were found to have a single epileptogenic lesion on MRI (lesional epilepsy). Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) were each completed in nine patients (7.0%) and magnetoencephalography (MEG) in four patients (3.1%). Despite the low utilization rate of adjunctive studies, over half (56.3%) ultimately underwent VNS alone, and 8.6% ultimately underwent definitive intracranial resection or disconnection surgery. CONCLUSIONS: The underutilization of appropriate non-invasive, presurgical testing in patients with focal DRE may in part explain the continued underutilization of definitive, resective/disconnective surgery. For patients without access to a high-volume, multidisciplinary surgical epilepsy center, adjunctive presurgical studies [e.g., PET, SPECT, MEG, electrical source imaging (ESI), EEG-functional magnetic resonance imaging (fMRI)], even when available, are rarely ordered, and this may contribute to excessive rates of VNS in lieu of definitive intracranial surgery.

A journey into the unknown: An ethnographic examination of drug-resistant epilepsy treatment and management in the United States.

Patients often recognize unmet needs that can improve patient-provider experiences in disease treatment management. These needs are rarely captured and may be hard to quantify in difficult-to-treat disease states such as drug-resistant epilepsy (DRE). To further understand challenges living with and managing DRE, a team of medical anthropologists conducted ethnographic field assessments with patients to qualitatively understand their experience with DRE across the United States. In addition, healthcare provider assessments were conducted in community clinics and Comprehensive Epilepsy Centers to further uncover patient-provider treatment gaps. We identified four distinct stages of the treatment and management journey defined by patients' perceived control over their epilepsy: Gripped in the Panic Zone, Diligently Tracking to Plan, Riding a Rollercoaster in the Dark, and Reframing Priorities to Redefine Treatment Success. We found that patients sought resources to streamline communication with their care team, enhanced education on treatment options beyond medications, and long-term resources to protect against a decline in control over managing their epilepsy once drug-resistant. Likewise, treatment management optimization strategies are provided to improve current DRE standard of care with respect to identified patient-provider gaps. These include the use of digital disease management tools, standardizing neuropsychiatrists into patients' initial care team, and introducing surgical and non-pharmacological treatment options upon epilepsy and DRE diagnoses, respectively. This ethnographic study uncovers numerous patient-provider gaps, thereby presenting a conceptual framework to advance DRE treatment. Further Incentivization from professional societies and healthcare systems to support standardization of the treatment optimization strategies provided herein into clinical practice is needed.

The utilization of sodium fluorescein in pediatric brain stem gliomas: a case report and review of the literature.

INTRODUCTION: A major challenge in the surgical resection of brainstem tumors is distinguishing tumor from normal tissue. One approach for addressing this problem is the use of fluorescent tracers such as sodium fluorescein (NaFl). NaFl disseminates through a disruption in the blood-brain barrier (BBB) and accumulates in the extracellular space of brain tumors. Intraoperative fluorescence microscopy can be performed to identify tumor tissue and avoid damage to adjacent, normal tissue. Here, we present the case of a 16-year-old male who underwent a left retrosigmoid craniotomy with splitting of the tentorium to remove a large exophytic brainstem tumor involving the cerebellar peduncle and with superior extension into the midbrain and thalamus. OBJECTIVES: The primary objective of this study was to investigate the effectiveness of sodium fluorescein as an intraoperative technique and evaluate its potential benefit for resection of tumors in eloquent regions in the pediatric population. To do so, we focused on a case study approach; however, we also performed a literature review and evaluated different intraoperative fluorescent techniques and their benefits for tumor resection. METHODS: We performed a literature search using PubMed and Google Scholar by the key words "sodium fluorescein," "brain stem tumor," and "central nervous system neoplasms." Twenty-nine articles including both pediatric and adult populations were selected for analysis and qualitative review. RESULTS: In this case study, sodium fluorescein helped the surgeons to identify and obtain a gross total resection of a large brainstem tumor. The marker was especially helpful for discerning the inferior pole of the tumor buried inconspicuously in cerebellar tissue. We evaluate different fluorescent tracers, 5-ALA and ICG, and discuss their application and benefits in tumor resection surgery. We present different cases that found sodium fluorescein to be helpful in achieving a gross total resection. CONCLUSION: The application of sodium fluorescein proved to be a safe and effective technique for the resection of brain stem tumors as shown in this case study. It helped to expose concealed areas and illuminate the tumor capsule. Further studies should test the clinical use of sodium fluorescein on brain stem tumor resection.

Deciphering the surgical treatment gap for drug-resistant epilepsy (DRE): A literature review.

Patients with drug-resistant epilepsy (DRE) rarely achieve seizure freedom with medical therapy alone. Despite being safe and effective for select patients with DRE, epilepsy surgery remains heavily underutilized. Multiple studies have indicated that the overall rates of surgery in patients with DRE have stagnated in recent years and may be decreasing, even when hospitalizations for epilepsy-related problems are on the rise. Ultimately, many patients with DRE who might otherwise benefit from surgery continue to have intractable seizures, lacking access to the full spectrum of available treatment options. In this article, we review the various factors accounting for the persistent underutilization of epilepsy surgery and uncover several key themes, including the persistent knowledge gap among physicians in identifying potential surgical candidates, lack of coordinated patient care, patient misconceptions of surgery, and socioeconomic disparities impeding access to care. Moreover, factors such as the cost and complexity of the preoperative evaluation, a lack of federal resource allocation for the research of surgical therapies for epilepsy, and difficulties recruiting patients to clinical trials all contribute to this multifaceted dilemma.

Treatment options and long-term outcomes in pediatric spinal cord vascular malformations: a case report and review of the literature.

A 16-month-old female was admitted for prolonged fever, gait ataxia, and neurogenic bowel and bladder. Neurological exam was significant for decreased sensory and motor functions in bilateral lower extremities. Initial MRI showed a thoracic spine hematoma and diagnostic angiogram revealed a large AVM and aneurysm. The patient underwent surgical resection of the hematoma and AVM, as well as clipping and later endovascular coiling of the aneurysm. Due to significant hemorrhage perioperatively, she developed spastic paraplegia improved by baclofen and onabotulinumtoxin A injections. The aims of this paper were to conduct a systematic review of the literature on pediatric spinal cord vascular malformations and analyze trends in treatment options and long-term neurological outcomes. PubMed searches were conducted using keywords "pediatric spinal vascular malformation" and "pediatric spinal AVM", yielding 34 results after abstract screening and cross-reference. Endovascular embolization was determined to have better long-term outcomes, with 10/19 (52.6%) patients with postoperative complications associated with open vascular surgeries. Open versus endovascular surgical decisions can be difficult with unique spinal AVM pathologies in pediatric patients. Important considerations such as size, location, neurological deficits, and risk of rupture are important factors to consider in treating these patients. We recommend endovascular treatment as a first-line approach due to lower risk of hemorrhage and postoperative deficits.

Traumatic Occipitocervical Distraction Injuries in Children: A Systematic Review.

BACKGROUND: Occipitocervical distraction injuries (OCDI) in children occur on a wide spectrum of severity, and decisions about treatment suffer from a lack of rigorous guidelines and significant inter-institutional variability. While clear cases of frank atlanto-occipital dislocation (AOD) are treated with surgical stabilization, the approach for less severe cases of OCDI is not standardized. These patients require a careful assessment of both radiographic and clinical criteria, as part of a complex risk-benefit analysis, to establish whether occipitocervical fusion (OCF) is indicated. Here, we performed a systematic review of the literature that describes traumatic OCDI in children < 18 years of age. SUMMARY: We performed a systematic review, according to PRISMA guidelines, of children < 18 years of age presenting with traumatic etiologies of OCDI. We searched PubMed to identify papers congruent with these criteria. Exclusion criteria included (1) reports on atraumatic causes of OCDI and (2) studies with insufficient clinical and radiographic details on individual patients. We identified 16 reports describing a total of 144 patients treated for pediatric traumatic OCDI. Based on the synthesis of these findings and the collective experience of the authors, we present the demographic, clinical, and radiographic factors that underlie OC instability, which we hope will serve as components of a grading system in the future. We considered various clinical and radiographic findings including: (1) the mechanism of injury, (2) the patient's age, (3) CT/CT angiography of head and neck findings and parameters, (4) MRI findings, and (5) neurological exam, for the purpose of determining the severity of the OCDI and offering treatment guidelines based on the summative risk of underlying OC instability. Key Messages: OCDI is a potentially devastating injury, especially in children. Although missing the diagnosis can have potentially catastrophic consequences, reverting to surgical fixation in less severe cases can subject children to unnecessary operative risk and permanently reduce their range of motion. After reviewing all the available reports of pediatric traumatic OCDI in the neurosurgical literature, we propose an outline of clinical and radiographic factors influencing underlying OC instability that could be incorporated into a grading scale to guide treatment. We hope this study stimulates discussion on the standardization of treatment for pediatric OCDI.

Delayed Intraparenchymal and Intraventricular Hemorrhage Requiring Surgical Evacuation after MRI-Guided Laser Interstitial Thermal Therapy for Lesional Epilepsy.

BACKGROUND: Symptomatic intracranial hemorrhage is a rare complication of laser interstitial thermal therapy (LITT). OBJECTIVES: To present a unique case of delayed symptomatic intracranial hemorrhage occurring after a LITT procedure for epilepsy in a high-volume center (68 LITT procedures for pediatric epilepsy have been performed). METHODS: An 18-year-old male with epilepsy underwent LITT to an area of heterotopia near the right lateral ventricle. He did well initially and was discharged home on postoperative day 1 but returned on postoperative day 9 with headache and left hemiparesis. He was found to have intraparenchymal and intraventricular hemorrhage in the region of the LITT catheter tract. RESULTS: CT angiography on admission revealed a small vascular abnormality near the focus of hemorrhage suspicious for pseudoaneurysm, although conventional angiography was negative. The patient declined neurologically and underwent craniotomy and hemorrhage evacuation. He eventually convalesced and was discharged to inpatient rehabilitation with persistent left hemiparesis. He has been seizure free since the intervention but remains on antiepileptic drugs. CONCLUSIONS: Evidence from the literature suggests that the pathophysiology of symptomatic hemorrhage after LITT may be related to vascular injury and pseudoaneurysm formation from LITT catheter placement and/or thermal injury from the ablation itself.

Instrumented fusion in a 12-month-old with atlanto-occipital dislocation: case report and literature review of infant occipitocervical fusion.

BACKGROUND: The treatment of atlantoaxial dislocation in very young children is challenging and lacks a consensus management strategy. DISCUSSION: We review the literature on infantile occipitocervical (OC) fusion is appraised and technical considerations are organized for ease of reference. Surgical decisions such as graft type and instrumentation details are summarized, along with the use of bone morphogenic protein and post-operative orthoses. ILLUSTRATIVE CASE: We present the case of a 12-month-old who underwent instrumented occipitocervical (OC) fusion in the setting of traumatic atlanto-occipital dislocation (AOD). CONCLUSION: Occipitocervical (OC) arthrodesis is obtainable in very young infants and children. Surgical approaches are variable and use a combination of autologous grafting and creative screw and/or wire constructs. The heterogeneity of pathologic etiology leading to OC fusion makes it difficult to make definitive recommendations for surgical management.

Non-convulsive status epilepticus and non-convulsive seizures in neurological ICU patients.

BACKGROUND: Non-convulsive seizures (NCS) or non-convulsive status epilepticus (NCSE) has been reported in 8-20 % of critically ill patient populations, and delayed diagnosis and treatment of NCSE may lead to increased mortality. This study seeks to better understand the risk factors, characteristics, and outcome of NCS/NCSE in the neurological ICU. METHODS: This is a prospective observational study, recruiting consecutive patients admitted to the adult neurological ICU with altered mental status. Patients with anoxic brain injury were excluded from the study. Data were collected and analyzed for prevalence of NCSE/NCS, EEG patterns, associated risk factors, treatment response, and final outcome. RESULTS: NCSE/NCS was detected in 21 % of 170 subjects. Clinical seizures preceded EEG diagnosis of NCSE/NCS in 25 % of cases. Significant risk factors for NCSE/NCS were a past medical history of intracranial tumor, epilepsy, or meningitis/encephalitis, or MRI evidence of encephalomalacia. Subtle clinical findings such as twitching of oral or ocular muscles and eye deviations were found on exam in 50 % of the NCSE/NCS group. Mortality was increased in NCSE cases as 31 % of NCSE/NCS patients died compared to 14 % in non-NCSE/NCS group. CONCLUSIONS: Specific clinical features along with history and imaging findings may be used to identify patients at high risk of NCSE/NCS in the neurological ICU.

Minimally invasive transpsoas L2 corpectomy and percutaneous pedicle screw fixation for osteoporotic burst fracture in the elderly: a technical report.

BACKGROUND AND IMPORTANCE: Osteoporotic vertebral burst fractures are an increasingly common cause of pain and severe functional disability in the elderly. Although anterior-posterior surgical stabilization offers an efficacious and durable treatment, the associated high blood loss, long durations of surgery, and prolonged hospitalization are often not tolerable for elderly patients, who are most often medically frail with multiple comorbidities. CLINICAL PRESENTATION: We report a case of an L2 osteoporotic burst fracture in an elderly patient with significant comorbidities treated with a minimally invasive tubular direct lateral transpsoas approach for L2 vertebrectomy and anterior cage placement. The construct was supplemented by a percutaneous pedicle screw construct and adjacent level vertebroplasty. Duration of surgery was 3.5 hours with a total of 35 mL blood loss. The patient was discharged ambulating 36 hours after surgery and reported marked improvement in pain, disability, and quality of life measures at 6 weeks postoperatively. CONCLUSIONS: L2 vertebrectomy by direct lateral transpsoas tube systems supplemented by percutaneous pedicle screws can be performed safely and may allow for anterior column decompression and reconstruction in elderly or comorbid patients not otherwise able to tolerate traditional stabilization procedures.

Cervical Diastematomyelia: A Case Presentation and Systematic Review.

Diastematomyelia is a rare congenital disorder characterized by the separation of the spinal cord by an osseocartilaginous or fibrous septum. While diastematomyelia has been reported to be more common in the thoracic and lumbar regions, the true incidence of cervical diastematomyelia is currently unknown. In this study, we conducted the most comprehensive systematic review to date of all other case reports of diastematomyelia to better characterize the incidence of cervical diastematomyelia and provide comprehensive statistics on the clinical characteristics of diastematomyelia generally. Ninety-one articles were included in our study, which comprised 252 males (27.9%) and 651 females (72.0%) (and one patient with unspecified gender). In 507 cases, the vertebral level of the diastematomyelia was described, and we recorded those levels as either cervical ( n = 8, 1.6%), thoracic ( n = 220, 43.4%), lumbar ( n = 277, 54.6%), or sacral ( n = 2, 0.4%). In 719 cases, the type of diastematomyelia was specified as either Type I ( n = 482, 67.0%) or Type II ( n = 237, 33.0%). Our study found that diastematomyelia has been reported in the cervical region in only 1.6% of cases, and we provide comprehensive data that this disorder occurs in female-to-male ratio of approximately 2.6:1 and Type I versus Type II diastematomyelia in an estimated ratio of 2:1.

Time to First Shunt Failure in Pediatric Patients over 1 Year Old: A 10-Year Retrospective Study.

Studies comparing alternatives to ventriculoperitoneal (VP) shunting for treatment of hydrocephalus have often relied upon data from an earlier era that may not be representative of contemporary shunt survival outcomes. We sought to determine the shunt survival rate of our cohort and compare our results to previously published shunt survival and endoscopic third ventriculostomy (ETV) success rates. We identified 95 patients between 1 and 18 years of age, who underwent initial VP shunt placement between January 2001 and December 2010. Our study shows a shunt survival rate of 85% at 6 months and 79% at 2 years, for initial shunts in pediatric patients over 1 year of age in this cohort. The overall infection rate was 3%. This compares favorably with published success rates of ETV at similar time points as well as with the rate of infection. This suggests that ventricular shunting remains a viable alternative to ETV in the older child.

Gross Total Resection of a Ruptured Micro-arteriovenous Malformation within the Cerebellar Peduncle: A Case Report and Qualitative Review of the Literature.

Deep-seated micro-arteriovenous malformations (micro-AVMs) may pose a challenge for complete yet safe resection. We propose the strategic placement of two to three microaneurysm clips throughout the hemorrhage cavity to successfully localize the micro-AVM nidus via digital subtraction angiography (DSA). We successfully demonstrate this novel method in a 15-year-old adolescent boy with cerebellar intraparenchymal hemorrhage who underwent hematoma evacuation and expansile duraplasty. He was found to have a 1-cm nidus of a micro-AVM with early venous drainage located in the right middle cerebellar peduncle. Five days later, we proceeded to resect the micro-AVM; however, a clear nidus or bleeding source was unable to be localized intraoperatively despite the use of stereotactic neuronavigation. In turn, we placed two mini-aneurysm clips superiorly and inferiorly within the hematoma cavity, which led to successful localization via DSA and complete resection. No surgical complications occurred. The patient completely recovered from right-sided weakness and dysarthria 6 to 12 months postoperatively. Our technique allows for the rapid localization and complete resection of micro-AVM nidi when stereotactic neuronavigation is inadequate.

Predictors of outcomes after surgery for medically intractable insular epilepsy: A systematic review and individual participant data meta-analysis.

Insular epilepsy (IE) is an increasingly recognized cause of drug-resistant epilepsy amenable to surgery. However, concerns of suboptimal seizure control and permanent neurological morbidity hamper widespread adoption of surgery for IE. We performed a systematic review and individual participant data meta-analysis to determine the efficacy and safety profile of surgery for IE and identify predictors of outcomes. Of 2483 unique citations, 24 retrospective studies reporting on 312 participants were eligible for inclusion. The median follow-up duration was 2.58 years (range, 0-17 years), and 206 (66.7%) patients were seizure-free at last follow-up. Younger age at surgery (≤18 years; HR = 1.70, 95% CI = 1.09-2.66, P = .022) and invasive EEG monitoring (HR = 1.97, 95% CI = 1.04-3.74, P = .039) were significantly associated with shorter time to seizure recurrence. Performing MR-guided laser ablation or radiofrequency ablation instead of open resection (OR = 2.05, 95% CI = 1.08-3.89, P = .028) was independently associated with suboptimal or poor seizure outcome (Engel II-IV) at last follow-up. Postoperative neurological complications occurred in 42.5% of patients, most commonly motor deficits (29.9%). Permanent neurological complications occurred in 7.8% of surgeries, including 5% and 1.4% rate of permanent motor deficits and dysphasia, respectively. Resection of the frontal operculum was independently associated with greater odds of motor deficits (OR = 2.75, 95% CI = 1.46-5.15, P = .002). Dominant-hemisphere resections were independently associated with dysphasia (OR = 13.09, 95% CI = 2.22-77.14, P = .005) albeit none of the observed language deficits were permanent. Surgery for IE is associated with a good efficacy/safety profile. Most patients experience seizure freedom, and neurological deficits are predominantly transient. Pediatric patients and those requiring invasive monitoring or undergoing stereotactic ablation procedures experience lower rates of seizure freedom. Transgression of the frontal operculum should be avoided if it is not deemed part of the epileptogenic zone. Well-selected candidates undergoing dominant-hemisphere resection are more likely to exhibit transient language deficits; however, the risk of permanent deficit is very low.

Open surgical disconnection for congenital, multi-hole, pial arteriovenous fistulae in non-eloquent cortex.

Intracranial pial arteriovenous fistulae (pAVFs), a direct shunt between a feeding artery and a venous channel with the absence of a true nidus characteristic of other types of arteriovenous malformations, are rare. We report a seven-year-old girl with an incidental intracranial pAVF. Following partial embolization with a combination of platinum coils and liquid embolic material, this lesion was surgically disconnected and a definitive cure was achieved. Based on the particular characteristics of this lesion-multiple, small arterial feeders, superficial location, and proximity to the non-eloquent cortex-we feel this vascular lesion represents a subset of pAVFs that may be most reasonably and safely treated by open surgery. While staged embolization has recently gained popularity as a treatment option, the additive risk of multiple embolizations as well as repeated exposure to ionizing radiation should not be understated, especially in the pediatric population. Furthermore, given the paucity of data on the long-term effectiveness of embolization, surgery remains an elegant and durable treatment option for pAVFs in carefully selected patients.

MRI based composite parameter of multiple tissue types for improved patient-level hemispheric and regional level lateralization in pediatric epilepsy.

Although voxel-based morphometry (VBM) of gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) changes aid in epileptic seizure lateralization, type of T1 pulse sequence, preprocessing steps and tissue segmentation methods lead to variation in tissue classification. Here, we test the prediction accuracy of individual MRI based tissue types and a novel composite ratio parameter [(GM + WM)/CSF], sensitive to parenchymal changes and independent of tissue classification variations. Pediatric patients with partial seizures (both simple and complex), but normal and lesion-free MRI were considered (33 patients; unilateral EEG; 17 female / 16 male; age mean ± SD = 11.5 ± 5 years). MRI based seizure lateralization was performed for each patient and verified with EEG findings alone or in combination with seizure semiology. T1 weighted MRI from patients and normal control subjects was spatially transformed to the Talairach atlas and automatically segmented into GM, WM and CSF tissue types. 41 age matched normal controls (11 female / 30 male; age mean ± SD = 14.6 ± 3 years) served as the null distribution to test tissue type deviations across each epilepsy patient. When verified with the patient EEG prediction, WM, GM and CSF had a hemispheric match of 76%, 70% and 55% respectively, while the composite ratio [(GM + WM)/CSF)] showed the highest accuracy of 85%. When EEG findings and seizure semiology were combined, MRI predictions using the composite ratio improved further to 88%. To further localize the epileptic focus, regional level (frontal, temporal, parietal and occipital) MRI predictions were obtained. The composite ratio performed at 88-91% accuracy, revealing regional MRI changes, not predictable with EEG. The results show inconsistent changes in GM and WM in majority of the pediatric epilepsy patients and demonstrate the applicability of the composite ratio [(GM + WM)/CSF)] as a superior predictor, independent of tissue classification variations. Clinical EEG findings combined with seizure semiology, can overcome scalp EEG's limitations and lean towards the MRI lateralization in specific cases.

Corpus Callosotomy in the Modern Era: Origins, Efficacy, Technical Variations, Complications, and Indications.

Corpus callosotomy is among the oldest surgeries performed for drug-resistant epilepsy. Since it was first performed in 1940, numerous studies have assessed its outcomes in various patient populations in addition to describing different extents of sectioning and emerging technologies (i.e., endoscopic, laser interstitial thermal therapy, and radiosurgery). To capture the current state and offer a reappraisal, we comprehensively review the origins of corpus callosotomy, efficacy for various seizure types, technical variations, complications, and indications and compare the procedure with vagus nerve stimulation therapy, which has similar indications. We consider corpus callosotomy to be a safe and efficacious procedure, which should be considered by clinicians when appropriate. Furthermore, it can play an important role in treating patients with drug-resistant epilepsy when appropriate in low-to-middle-income countries where resources are limited.

Findings on preoperative brain MRI predict histopathology in children with cerebellar neoplasms.

BACKGROUND/AIMS: The majority of pediatric patients with cerebellar neoplasms harbor pilocytic astrocytomas (PAs), medulloblastomas, or ependymomas. Knowledge of a preoperative likelihood of histopathology in this group of patients has the potential to influence many aspects of care. Previous studies have demonstrated hyperintensity on diffusion-weighted imaging to correlate with medulloblastomas. Recently, measurement of T(2)-weighted signal intensity (T2SI) was shown to be useful in identification of low-grade cerebellar neoplasms. The goal of this study was to assess whether objective findings on these MRI sequences reliably correlated with the underlying histopathology. METHODS: We reviewed the radiologic findings of 50 pediatric patients who underwent resection of a cerebellar neoplasm since 2003 at our institution. Region of interest placement was used to calculate the relative diffusion-weighted signal intensity (rDWSI) and relative T2SI (rT2SI) of each neoplasm. RESULTS: Tukey's multiple comparison test demonstrated medulloblastomas to have significantly higher rDWSIs than PAs/ependymomas, and PAs to have significantly higher rT2SIs than medulloblastomas/ependymomas. A simple method consisting of sequential measurement of rDWSI and rT2SI to predict histopathology was then constructed. Using this method, 39 of 50 (78%) tumors were accurately predicted. CONCLUSION: Measurement of rDWSI and rT2SI using standard MRI of the brain can be used to predict histopathology with favorable accuracy in pediatric patients with cerebellar tumors.

Sodium Fluorescein-Guided Gross Total Resection of Pediatric Exophytic Brainstem Glioma: 2-Dimensional Operative Video.

Brainstem gliomas comprise 10% to 20% of pediatric intracranial tumors.1 Gross total resection is associated with the greatest long-term survival.1 However, due to the eloquence of surrounding brain tissue, an aggressive resection is not always achievable and can be associated with significant risk.2 Sodium fluorescein can be used to help differentiate between tumor and normal tissue.3,4 In this operative video, we demonstrate the step-by-step technique to utilize fluorescence in surgically resecting an exophytic glioma arising from the midbrain in a 16-yr-old male. Technical nuances are highlighted in this operative video, including the use of the YELLOW 560 (Zeiss) filter to differentiate fluorescent tumor from normal tissue as well as strategic splitting of the tentorium to expose the supratentorial component of the tumor. A decrease in motor potentials of the right leg during the case did not translate into neurological worsening postoperatively; at 3-mo follow-up, the patient attests to better strength and coordination on his affected side. In summary, sodium fluorescein can be used as a critical adjunctive tool for successful surgery in the case of a brainstem tumor. Alternatives to this procedure included gross total resection with 5-aminolevulinic acid, subtotal resection with chemotherapy, and active monitoring, but were not chosen due to their limitations in this clinical case.5-7 Appropriate patient consent was obtained to perform this procedure and present this clinical case and surgical video for academic purposes.