Current Applications of VR/AR (Virtual Reality/Augmented Reality) in Pediatric Neurosurgery.

Neurosurgical procedures are some of the most complex procedures in medicine and since the advent of the field, planning, performing, and learning them has challenged the neurosurgeon. Virtual reality (VR) and augmented reality (AR) are making these challenges more manageable. VR refers to a virtual digital environment that can be experienced usually through use of stereoscopic glasses and controllers. AR, on the other hand, fuses the natural environment with virtual images, such as superimposing a preoperative MRI image on to the surgical field [1]. They initially were used primarily as neuronavigational tools but soon their potential in other areas of surgery, such as planning, education, and assessment, was noted and explored. Through this chapter, we outline the history and evolution of these two technologies over the past few decades, describe the current state of the technology and its uses, and postulate future directions for research and implementation.

Outcomes of surgical revascularization for pediatric moyamoya disease and syndrome.

PURPOSE: Moyamoya disease and syndrome represent rare entities characterized by progressive stenosis and/or occlusion of the intracranial blood vessels. We present our series of patients with moyamoya disease and syndrome stratified by underlying disease and analyze differences in presentation and outcome following surgical revascularization. METHODS: This was an Institutional Review Board (IRB) approved, retrospective review of all patients surgically revascularized by the senior author (SNM) while at Children's National Hospital in Washington, DC. Demographic data, presenting symptoms and severity, surgical details, and functional and radiographic outcomes were obtained and analyzed for differences among the underlying cohorts of moyamoya disease and syndrome as well as by unilateral or bilateral disease and index or non-index surgeries. RESULTS: Twenty-two patients were identified with the following underlying diseases: six with idiopathic moyamoya disease, six with sickle cell anemia, five with trisomy 21, and five with neurofibromatosis type 1. Thirty hemispheres were revascularized with a significantly reduced rate of stroke from 3.19 strokes/year (SD = 3.10) to 0.13 strokes/year (SD = 0.25), p = 0.03. When analyzed by underlying cause of moyamoya syndrome, patients with neurofibromatosis type 1 were found to be significantly less likely than the other subtypes of moyamoya syndrome to have had either a clinical stroke (0.0% neurofibromatosis type 1 vs. 100.0% sickle cell, 60.0% trisomy 21, or 83.3% moyamoya disease, p < 0.01) or radiographic stroke (0.0% neurofibromatosis type 1 vs. 100.0% sickle cell, 60.0% trisomy 21, or 83.3% moyamoya disease, p < 0.01) at time of presentation. Patients with moyamoya syndrome associated with sickle cell disease were more likely to present with clinical and radiographic strokes. Additionally, patients with bilateral disease demonstrated no difference in final functional outcome compared to patients with unilateral disease (mRS 0.73 (SD = 1.33) vs. 1.29 (SD = 1.60), p = 0.63). CONCLUSION: Indirect surgical revascularization decreases stroke risk for pediatric patients with different forms of moyamoya disease and moyamoya syndrome. Additionally, these data suggest that sickle cell anemia-associated moyamoya syndrome may represent a more aggressive variant, while neurofibromatosis type 1 may represent a more benign variant.

Isolated subependymal giant cell astrocytoma (SEGA) in the absence of clinical tuberous sclerosis: two case reports and literature review.

PURPOSE: Subependymal giant cell astrocytoma (SEGA) is a WHO grade I pediatric glioma arising in 5-15% of patients with tuberous sclerosis (TSC). Rare cases of isolated SEGA without TSC have been described. The etiology, genetic mechanisms, natural history, and response to treatment of these lesions are currently unknown. We describe two such cases of isolated SEGA with follow-up. METHODS: Retrospective review was performed at a single institution to describe the clinical course of pathology-confirmed SEGA in patients with germline testing negative for TSC mutations. RESULTS: Two cases of isolated SEGA were identified. Genetic analysis of the tumor specimen was available for one, which revealed an 18 base pair deletion in TSC1. Both cases were managed with surgical resection, one with preoperative embolization. In spite of a gross total resection, one patient experienced recurrence after three years. Treatment with an mTOR inhibitor led to a significant interval reduction of the mass on follow-up MRI. The patient tolerated the medication well for 6 years and is now off of treatment for 2 years with a stable lesion. CONCLUSION: Cases of SEGA outside of the context of TSC are exceedingly rare, with only 48 cases previously described. The genetic mechanisms and treatment response of these lesions are poorly understood. To date, these lesions appear to respond well to mTOR inhibitors and may behave similarly to SEGAs associated with TSC. However, given that experience is extremely limited, these cases should be followed long term to better understand their natural history and treatment response.

The role of focused ultrasound for pediatric brain tumors: current insights and future implications on treatment strategies.

INTRODUCTION: Focused ultrasound (FUS) is an innovative and emerging technology for the treatment of adult and pediatric brain tumors and illustrates the intersection of various specialized fields, including neurosurgery, neuro-oncology, radiation oncology, and biomedical engineering. OBJECTIVE: The authors provide a comprehensive overview of the application and implications of FUS in treating pediatric brain tumors, with a special focus on pediatric low-grade gliomas (pLGGs) and the evolving landscape of this technology and its clinical utility. METHODS: The fundamental principles of FUS include its ability to induce thermal ablation or enhance drug delivery through transient blood-brain barrier (BBB) disruption, emphasizing the adaptability of high-intensity focused ultrasound (HIFU) and low-intensity focused ultrasound (LIFU) applications. RESULTS: Several ongoing clinical trials explore the potential of FUS in offering alternative therapeutic strategies for pathologies where conventional treatments fall short, specifically centrally-located benign CNS tumors and diffuse intrinsic pontine glioma (DIPG). A case illustration involving the use of HIFU for pilocytic astrocytoma is presented. CONCLUSION: Discussions regarding future applications of FUS for the treatment of gliomas include improved drug delivery, immunomodulation, radiosensitization, and other technological advancements.

Evolution of Surgical Management of Pineal Region Tumors in the Pediatric Population: A 17-Year Experience at a Single Institution.

INTRODUCTION: Pineal region tumors have historically been challenging to treat. Advances in surgical techniques have led to significant changes in care and outcomes for these patients, and this is well demonstrated by our single institution's experience over a 17-year-period in which the evolution of diagnosis, treatment, and outcomes of pineal tumors in pediatric patients will be outlined. METHODS: We retrospectively collected data on all pediatric patients with pineal region lesions treated with surgery at Children's National Hospital (CNH) from 2005 to 2021. Variables analyzed included presenting symptoms, presence of hydrocephalus, diagnostic and surgical approach, pathology, and adverse events, among others. IRB approval was obtained (IRB: STUDY00000009), and consent was waived due to minimal risk to patients included. RESULTS: A total of 43 pediatric patients with pineal region tumors were treated during a 17-year period. Most tumors in our series were germinomas (n = 13, 29.5%) followed by pineoblastomas (n = 10, 22.7%). Twenty seven of the 43 patients (62.8%) in our series received a biopsy to establish diagnosis, and 44.4% went on to have surgery for resection. The most common open approach was posterior interhemispheric (PIH, transcallosal) - used for 59.3% of the patients. Gross total resection was achieved in 50%; recurrence occurred in 20.9% and mortality in 11% over a median follow-up of 47 months. Endoscopic third ventriculostomy (ETV) was employed to treat hydrocephalus in 26 of the 38 patients (68.4%) and was significantly more likely to be performed from 2011 to 2021. Most (73%) of the patients who received an ETV also underwent a concurrent endoscopic biopsy. No difference was found in recurrence rate or mortality in patients who underwent resection compared to those who did not, but complications were more frequent with resection. There was disagreement between frozen and final pathology in 18.4% of biopsies. CONCLUSION: This series describes the evolution of surgical approaches and outcomes over a 17-year-period at a single institution. Complication rates were higher with open resection, reinforcing the safety of pursuing endoscopic biopsy as an initial approach. The most significant changes occurred in the preferential use of ETVs over ventriculoperitoneal shunts. Though there has been a significant evolution in our understanding of and treatment for these tumors, in our series, the outcomes for these patients have not significantly changed over that time.

Deep brain stimulation and intrathecal/intraventricular baclofen for glutaric aciduria type 1: A scoping review, individual patient data analysis, and clinical trials review.

Glutaric aciduria type 1 (GA1) is an autosomal recessive disease frequently leading to dystonia. Deep brain stimulation (DBS), intrathecal baclofen (ITB), and intraventricular baclofen (IVB) are the current interventional treatment options for refractory dystonia. We performed a scoping review, individual patient data (IPD) analysis, and clinical trials review to summarize the existing literature on these interventions in this population, characterize outcomes, and suggest directions for future investigation. PubMed, Embase, and Scopus were searched following PRISMA guidelines. IPD were extracted from studies providing IPD for GA1 patients. ClinicalTrials.gov was reviewed. Of 139 articles, 7 studies with 10 patients were included. In study-level data, 2/4 (50.0%) DBS studies found no improvement in dystonia and 3/3 (100%) on baclofen found decreased dystonia and enteral medication regimen. In the IPD analysis, four studies with 5 patients (2 IVB, 2 DBS, 1 ITB) were included. The average percent reduction in dystonia was 29.9% ± 32.5% (median:18%, IQR:18%-29.2%). Function improved in 4 (80.0%) patients. All patients with reported changes in enteral dystonia-related medication regimen (3/3, 100%) reported reduction in medication usage. No patients (0%) had perioperative complications. Mean follow-up length was 14.8 ± 12.2 months. No interventional clinical trials were found. ITB, IVB, and DBS represent present neuromodulatory approaches for the treatment of GA1. ITB and IVB reduce dystonia, while DBS has a heterogeneous effect. ITB and IVB improved function and reduced enteral medication regimens. These findings must be viewed with caution considering limited data and a serious risk of bias. Further large-scale studies are necessary to determine indications for ITB, IVB, and DBS and elucidate treatment algorithms.

Medulloblastomas, CNS embryonal tumors, and cerebellar mutism syndrome: advances in care and future directions.

Central nervous system (CNS) embryonal tumors, commonly found in pediatric patients, represent a heterogeneous mix of lesions with an overall poor (though improving) prognosis. Medulloblastomas are by far the most frequently encountered and most widely studied subtype, though others include atypical teratoid/rhabdoid tumors (AT/RTs), embryonal tumor with multilayered rosettes (ETMRs), and CNS neuroblastomas, FOX-R2 activated. The classification, diagnosis, and treatment of these lesions have evolved drastically over the years as their molecular underpinnings have been elucidated. We describe the most recent 2021 WHO Classification system, discuss current understanding of the genetic basis, and demonstrate current thinking in treatment for these highly complex tumors. Since surgical resection continues to remain a mainstay of treatment, preventing and managing surgical complications, especially cerebellar mutism syndrome (CMS), is paramount. We describe the current theories for the etiology of CMS and two centers' experience in mitigating its risks. As our surgical toolbox continues to evolve along with our understanding of these tumors, we hope future patients can benefit from both improved overall survival and quality of life.

Prediction of shunt failure facilitated by rapid and accurate volumetric analysis: a single institution's preliminary experience.

BACKGROUND: Shunt malfunction is a common complication and often presents with hydrocephalus. While the diagnosis is often supported by radiographic studies, subtle changes in CSF volume may not be detectable on routine evaluation. The purpose of this study was to develop a novel automated volumetric software for evaluation of shunt failure in pediatric patients, especially in patients who may not manifest a significant change in their ventricular size. METHODS: A single-institution retrospective review of shunted patients was conducted. Ventricular volume measurements were performed using manual and automated methods by three independent analysts. Manual measurements were produced using OsiriX software, whereas automated measurements were produced using the proprietary software. A p value < 0.05 was considered statistically significant. RESULTS: Twenty-two patients met the inclusion criteria (13 males, 9 females). Mean age of the cohort was 4.9 years (range 0.1-18 years). Average measured CSF volume was similar between the manual and automated methods (169.8 mL vs 172.5 mL, p = 0.56). However, the average time to generate results was significantly shorter with the automated algorithm compared to the manual method (2244 s vs 38.3 s, p < 0.01). In 3/5 symptomatic patients whose neuroimaging was interpreted as stable, the novel algorithm detected the otherwise radiographically undetectable CSF volume changes. CONCLUSION: The automated software accurately measures the ventricular volumes in pediatric patients with hydrocephalus. The application of this technology is valuable in patients who present clinically without obvious radiographic changes. Future studies with larger cohorts are needed to validate our preliminary findings and further assess the utility of this technology.

Virtual reality-based 3-dimensional localization of stereotactic EEG (SEEG) depth electrodes and related brain anatomy in pediatric epilepsy surgery.

INTRODUCTION: The increasing use of stereoelectroencephalography (SEEG) in the USA and the need for three-dimensional (3D) appreciation of complex spatial relationships between implanted stereotactic EEG depth electrodes and surrounding brain and cerebral vasculature are a challenge to clinicians who are used to two-dimensional (2D) appreciation of cortical anatomy having been traditionally trained on 2D radiologic imaging. Virtual reality and its 3D renderings have grown increasingly common in the multifaceted practice of neurosurgery. However, there exists a paucity in the literature regarding this emerging technology in its utilization of epilepsy surgery. METHODS: An IRB-approved, single-center retrospective study identifying all SEEG pediatric patients in which virtual reality was applied was observed. RESULTS: Of the 46 patients identified who underwent an SEEG procedure, 43.5% (20/46) had a 3D rendering (3DR) of their SEEG depth electrodes. All 3DRs were used during patient-family education and discussion among the Epilepsy multidisciplinary team meetings, while 35% (7/20) were used during neuronavigation in surgery. Three successful representative cases of its application were presented. DISCUSSION: Our institution's experience regarding virtual reality in the 3D representation of SEEG depth electrodes and the application to pre-surgical planning, patient-family education, multidisciplinary communication, and intraoperative neuronavigation demonstrate its applicability in comprehensive epilepsy patient care.

Epilepsy surgery in infants up to 3 months of age: Safety, feasibility, and outcomes: A multicenter, multinational study.

OBJECTIVE: Drug-resistant epilepsy (DRE) during the first few months of life is challenging and necessitates aggressive treatment, including surgery. Because the most common causes of DRE in infancy are related to extensive developmental anomalies, surgery often entails extensive tissue resections or disconnection. The literature on "ultra-early" epilepsy surgery is sparse, with limited data concerning efficacy controlling the seizures, and safety. The current study's goal is to review the safety and efficacy of ultra-early epilepsy surgery performed before the age of 3 months. METHODS: To achieve a large sample size and external validity, a multinational, multicenter retrospective study was performed, focusing on epilepsy surgery for infants younger than 3 months of age. Collected data included epilepsy characteristics, surgical details, epilepsy outcome, and complications. RESULTS: Sixty-four patients underwent 69 surgeries before the age of 3 months. The most common pathologies were cortical dysplasia (28), hemimegalencephaly (17), and tubers (5). The most common procedures were hemispheric surgeries (48 procedures). Two cases were intentionally staged, and one was unexpectedly aborted. Nearly all patients received blood products. There were no perioperative deaths and no major unexpected permanent morbidities. Twenty-five percent of patients undergoing hemispheric surgeries developed hydrocephalus. Excellent epilepsy outcome (International League Against Epilepsy [ILAE] grade I) was achieved in 66% of cases over a median follow-up of 41 months (19-104 interquartile range [IQR]). The number of antiseizure medications was significantly reduced (median 2 drugs, 1-3 IQR, p < .0001). Outcome was not significantly associated with the type of surgery (hemispheric or more limited resections). SIGNIFICANCE: Epilepsy surgery during the first few months of life is associated with excellent seizure control, and when performed by highly experienced teams, is not associated with more permanent morbidity than surgery in older infants. Thus surgical treatment should not be postponed to treat DRE in very young infants based on their age.

Quantitative outcomes of endoscopic strip craniectomy for metopic craniosynostosis in children with severe trigonocephaly.

PURPOSE: To assess intermediate-term (> 3 years) outcomes of endoscopic strip craniectomy with postoperative helmet therapy (ESC + HT) for the treatment of infants with severe trigonocephaly. METHODS: This retrospective study examined cranial morphology of consecutive patients with severe trigonocephaly treated with minimally invasive ESC + HT. Preoperative and follow-up clinical parameters were collected from patient charts. Interfrontal divergence angle (IFDA), a validated and accurate measure of forehead narrowing, was measured on preoperative CT scans and on preoperative and postoperative 2D photographs. RESULTS: Seven patients (4 male, 3 female) were included with a mean age at surgery of 2.76 months (range 1.8 to 4.1 months) and mean clinical follow-up of 3.71 years (photographic follow-up 2.73 years). The mean operative time was 91.4 min, with a mean estimated blood loss (EBL) of 57.1 ml and mean hospital length of stay of 1.14 days. IFDA improved from 118.8° to 135.9° (p < 0.01), with the mean final measurement falling within normal limits. The head circumference percentile was not significantly changed in follow-up. There was a statistically significant improvement in the inner-to-outer canthal distance ratio (p = 0.01) in follow-up, showing an improvement in hypotelorism. There were no dural tears, CSF leaks, infections, or other significant surgical morbidities, and there were no serious complications related to the use of helmet therapy. All patients achieved excellent aesthetic results judged by photographic comparison. CONCLUSION: This study demonstrated that patients treated with ESC + HT for metopic craniosynostosis showed measurable and significant improvement in forehead shape. This technique is a safe and effective alternative to more invasive surgical interventions.

Long-term outcomes for children with an incidentally discovered Chiari malformation type 1: what is the clinical significance?

OBJECTIVES: Chiari malformation type 1 (CM1) is an increasingly common incidental finding on magnetic resonance imaging (MRI). The proportion of children with an incidentally discovered CM1 who upon further evaluation require operative intervention for previously unrecognized signs and symptoms of neurological compromise or significant radiographic findings (syringomyelia) is unclear. An extensive long-term single-institution patient series was evaluated to better clarify the likelihood of surgery in patients who present with an incidentally discovered CM1. METHODS: This study was conducted using prospective data for patients up to 18 years old that were evaluated for a CM1 at a large tertiary pediatric neurosurgery clinic between February 2009 and June 2019. Patients were excluded if they did not have an incidentally discovered CM1 and at least 12 months of clinical follow-up. RESULTS: A total of 218 consecutive patients were included in this study. The mean age at the initial neurosurgical evaluation was 6.5 years (range 5 months to 18.4 years), and the mean duration of clinical follow-up was 40.6 months (range 12 to 114 months). Initial MR imaging was most commonly obtained for the evaluation of seizures (15.1%), nonspecific headaches (not occipital or tussive) (14.7%), trauma (9.6%), and developmental delay (7.8%). Of the patients studied that eventually required surgery, we identified two groups: those operated before 6 months since presentation and those operated after 6 months. A total of 36 patients (16.5%) underwent a decompression with 22 patients (61.1%) receiving surgery within 6 months and the remaining 14 patients (38.9%) beyond 6 months. Patients undergoing early surgery (10.1%) initially presented with a significant syrinx or were noted to have an occult neurological dysfunction, whereas a smaller subset of patients (6.4%) eventually required surgery over time due to the development of new symptoms or a de novo syrinx. Only the presence of syringomyelia was statistically significant for the need of a surgical intervention, while age, sex and degree of tonsillar herniation were not. CONCLUSION: Evaluation of a large group of patients with an incidentally discovered Chiari malformation demonstrated that most patients may be managed conservatively, especially in the absence of syringomyelia. However, there is a subset of patients who will go on to develop a de novo syrinx or neurological symptoms that are new or progressive during follow-up, which should be evaluated by imaging of the brain and spinal cord. The presence of syringomyelia was associated with need for early surgical intervention. However, for patients without syringomyelia, surgical intervention is uncommon but may be delayed up to several years after presentation; therefore, long-term clinical follow-up is recommended.

Long-term outcomes of posterior fossa decompression for Chiari malformation type 1: which patients are most prone to failure?

PURPOSE: The role of an osseous-only posterior fossa decompression (PFD) for Chiari malformation type 1 (CM1) remains controversial. We reviewed long-term outcomes for patients with CM1 undergoing a PFD to evaluate if there was any difference for failure when compared to patients undergoing a PFD with duraplasty (PFDD). METHODS: Consecutive patients surgically treated at a single tertiary pediatric neurosurgery clinic over a 25-year period with at least 5 years of follow-up were evaluated. PFD patients were compared to those that initially received a PFDD. Demographics, surgical indications, surgical approach, outcomes, and complications were reviewed. RESULTS: A total of 60 patients were included in this study of which 25 (41.67%) underwent PFD and 35 (58.33%) underwent PFDD. Mean age at surgery was 7.41 years (range 0.4 to 18 years) with a mean follow-up of 8.23 years (range 5 to 21 years). Those that received a PFD had a lower rate of radiographic syrinx improvement (p = 0.03), especially in the setting of holocord syringes. Failure rate was significantly higher in the PFD group (20% vs 2.90%, p = 0.03). However, complications were significantly higher in the PFDD group (17.14% vs 4.0%, p = 0.04). CONCLUSIONS: PFD provides a safe treatment option with similar clinical improvements and lower post-operative complication rate compared to PFDD, albeit at the cost of greater chance of reoperation, especially in the setting of a holocord syrinx. Patients with a holocord syrinx should be considered for a PFDD as their initial procedure.

Three-dimensional printing and craniosynostosis surgery.

OVERVIEW: The goal of this study was to review the current application and status of three-dimensional printing for craniosynostosis surgery. METHODS: A literature review was performed using the PubMed/MEDLINE databases for studies published between 2010 and 2020. All studies demonstrating the utilization of three-dimensional printing for craniosynostosis surgery were included. RESULTS: A total of 15 studies were ultimately selected. This includes studies demonstrating novel three-dimensional simulation and printing workflows, studies utilizing three-dimensional printing for surgical simulation, as well as case reports describing prior experiences. CONCLUSION: The incorporation of three-dimensional printing into the domain of craniosynostosis surgery has many potential benefits. This includes streamlining surgical planning, developing patient-specific template guides, enhancing residency training, as well as aiding in patient counseling. However, the current state of the literature remains in the validation stage. Further study with larger case series, direct comparisons with control groups, and prolonged follow-up times is necessary before more widespread implementation is justified.

Cerebellar mutism syndrome: current approaches to minimize risk for CMS.

PURPOSE: Cerebellar mutism syndrome (CMS) is a serious source of morbidity following posterior fossa surgery in the pediatric population. However, methods for effectively decreasing its incidence and impact remain unclear. It is our aim to examine the impact of adjusting surgical factors, namely the use of a telovelar approach and avoidance of cavitronic ultrasonic aspirator, on the incidence of CMS in our population as well as outlining potential pre-, intra-, and postoperative factors that may contribute to its development. METHODS: Retrospective review was performed to identify patients undergoing posterior fossa surgery for resection of a medulloblastoma. Demographic, surgical, and postoperative data were collected. These data were analyzed for possible correlations to the risk of developing CMS via univariate analysis. For factors found to be significant, a multivariate analysis was performed to assess their independence. RESULTS: Seven of 65 patients (10.8%) developed CMS postoperatively. Factors found to be significantly associated with a higher risk of CMS were the degree of retraction utilized during the procedure (p = 0.0000) and incision of the vermis (p = 0.0294). Although they did not reach the threshold of statistical significance, tumor vascularity (p = 0.19), adoption of a transvermian approach (p = 0.19), and lack of intraoperative imaging (p = 0.17) exhibited strongly suggestive trends towards a correlation with CMS. DISCUSSION: In an effort to reduce the incidence and severity of CMS in our population, our institution adopted surgical practices that minimize tissue trauma and mitigate postoperative edema. This included the use of a telovelar over a transvermian approach to obviate the need for vermian incision, avoidance of the CUSA, and minimization of heavy retraction during surgery. This was successful in reducing the incidence of CMS from 39% in our medulloblastoma patients to 10.8%. The development of CMS after posterior fossa surgery appears to be a "two-hit" phenomenon requiring a combination of existing predisposition, surgical injury, and postoperative exacerbation. Therefore, it is critical to identify the factors involved at each stage and investigate treatments to target them appropriately.

An Initial Cost-Effectiveness Analysis of Magnetic Resonance-Guided Laser Interstitial Thermal Therapy in Pediatric Epilepsy Surgery.

INTRODUCTION: Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a new technology that provides a clinically efficacious and minimally invasive alternative to conventional microsurgical resection. However, little data exist on how costs compare to traditional open surgery. The goal of this paper is to investigate the cost-effectiveness of MRgLITT in the treatment of pediatric epilepsy. METHODS: We retrospectively analyzed the medical records of pediatric patients who underwent MRgLITT via the Visualase® thermal therapy system (Medtronic, Inc., Minneapolis, MN, USA) between December 2013 and September 2017. Direct costs associated with preoperative, operative, and follow-up care were extracted. Benefit was calculated in quality-adjusted life years (QALYs), and the cost-effectiveness was derived from the discounted total direct costs over QALY. Sensitivity analysis on 4 variables was utilized to assess the validity of our results. RESULTS: Twelve consecutive pediatric patients with medically refractory epilepsy underwent MRgLITT procedures. At the last postoperative follow-up, 8 patients were seizure free (Engel I, 66.7%), 2 demonstrated significant improvement (Engel II, 16.7%), and 2 patients showed worthwhile improvement (Engel III, 16.7%). The average cumulative discounted QALY was 2.11 over the lifetime of a patient. Adjusting for inflation, MRgLITT procedures had a cost-effectiveness of USD 22,211 per QALY. Our sensitivity analysis of cost variables is robust and supports the procedure to be cost--effective. CONCLUSION: Our data suggests that MRgLITT may be a cost-effective alternative to traditional surgical resection in pediatric epilepsy surgery.

Occult Scaphocephaly: A Forme Fruste Phenotype of Sagittal Craniosynostosis.

INTRODUCTION: Latent cranial suture fusions may present with mild or absent phenotypic changes that make the clinical diagnosis challenging. Recent reports describe patients with sagittal synostosis and a normal cranial index (CI), a condition termed normocephalic sagittal craniosynostosis (NSC). The goal of this study is to evaluate the shape and intracranial volume (ICV) in a cohort of NSC patients using quantitative cranial shape analysis (CSA). METHODS: We identified 19 patients (7.5 ±â€Š2.28 years) between 2011 and 2016, who presented to our hospital with NSC. Cranial index and CSA were measured from the computed tomography image. Cranial shape analysis calculates the distances between the patient's cranial shape and its closest normal shape. Intracranial volume was measured and compared to an established age-matched normative database. RESULTS: Cranial index revealed 15 (78.9%) patients within the mesocephalic range and 4 patients (21.1%) in the brachycephalic range. Detailed CSA identified 15 (78.9%) patients with subtle phenotypic changes along the scaphocephalic spectrum (ie, subtle anterior and posterior elongation with inter-parietal narrowing) and 1 patient (5.3%) with isolated overdevelopment on the posterior part of the right parietal bone. Three patients (15.8%) had a CSA close to normal. Mean ICV was 1410.5 ±â€Š192.77cc; most patients (78.9%) fell within ±2 standard deviations. CONCLUSION: Quantitative CSA revealed that most of the patients with NSC had cranial shape abnormalities, consistent with a forme fruste scaphocephaly that could not be otherwise recognized by clinical observation or CI. Given these findings, we propose the term occult scaphocephaly to describe this condition. The associated incidence of intracranial hypertension is unknown.

Management of Chiari I malformations: a paradigm in evolution.

PURPOSE: Despite decades of experience and research, the etiology and management of Chiari I malformations (CM-I) continue to raise more questions than answers. Controversy abounds in every aspect of management, including the indications, timing, and type of surgery, as well as clinical and radiographic outcomes. This review aims to outline past experiences, consolidate current evidence, and recommend directions for the future management of the Chiari I malformation. METHODS: A review of recent literature on the management of CM-I in pediatric patients is presented, along with our experience in managing 1073 patients who were diagnosed with CM-I over the past two decades (1998-2018) at Children's National Medical Center (CNMC) in Washington DC. RESULTS: The general trend reveals an increase in the diagnosis of CM-I at younger ages with a significant proportion of these being incidental findings (0.5-3.6%) in asymptomatic patients as well as a rise in the number of patients undergoing Chiari posterior fossa decompression surgery (PFD). The type of surgical intervention varies widely. At our institution, 104 (37%) Chiari surgeries were bone-only PFD with/without outer leaf durectomy, whereas 177 (63%) were PFD with duraplasty. We did not find a significant difference in outcomes between the PFD and PFDD groups (p = 0.59). An analysis of failures revealed a significant difference between patients who underwent tonsillar coagulation versus those whose tonsils were not manipulated (p = 0.02). CONCLUSION: While the optimal surgical intervention continues to remain elusive, there is a shift away from intradural techniques in favor of a simple, extradural approach (including dural delamination) in pediatric patients due to high rates of clinical and radiographic success, along with a lower complication rate. The efficacy, safety, and necessity of tonsillar manipulation continue to be heavily contested, as evidence increasingly supports the efficacy and safety of less tonsillar manipulation, including our own experience.

Magnetic resonance-guided laser interstitial thermal therapy for the treatment of non-lesional insular epilepsy in pediatric patients: thermal dynamic and volumetric factors influencing seizure outcomes.

PURPOSE: To investigate the safety and efficacy of stereoelectroencephalography (sEEG) directed magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) in medically refractory insular epilepsy in pediatric patients, define the relationship between ablation volumes and seizure control, and analyze the relationship between thermal energy and ablation volumes. METHODS: A single-institution, retrospective review of pediatric patients with insular epilepsy who underwent sEEG directed MRgLITT over a 10-month period was performed. Perioperative, imaging, and outcome data were analyzed. Seizure outcomes were determined based on Engel score (Engel I versus Engel II-IV). Insula and ablation volumes were measured, and the proportion of insula volume ablated was calculated. Thermal energy was calculated in joules. RESULTS: Four patients underwent sEEG directed MRgLITT of insular epileptogenic foci. The ablation volume was higher in patients with Engel I outcome (3.93 cm3) compared to Engel II-IV outcome (1.02 cm3). The proportion of ablation to insula volume was lowest in patients with Engel II-IV outcome (25.09%). The mean energy requirement to create a unit volume of ablation in the insula is 1205.86 J. A linear trend was noted between thermal ablation energy and ablation volume (R2 = 0.884). Over a mean follow-up period of 104 days, three patients were seizure-free (Engel I), and one patient saw significant improvement in seizure frequency (Engel III). CONCLUSIONS: The proportion of insula ablated, as well as the volume of ablation, are related to seizure outcome with increasing ablation volumes corresponding to improved seizure control. Further analysis of insula laser ablation thermal dynamics and volumes is needed.

Intraoperative Management by a Craniofacial Team Anesthesiologist is Associated With Improved Outcomes for Children Undergoing Major Craniofacial Reconstructive Surgery.

The benefits of using a dedicated team for complex surgeries are well established for certain specialties, but largely unknown for others. The aim of this study was to determine whether management by a dedicated craniofacial team anesthesiologist would impact perioperative outcomes for children undergoing major surgery for craniosynostosis. Sixty-two children undergoing complex cranial vault reconstruction were identified. Fifty-four patients were managed by the craniofacial anesthesia team, while 8 patients were not. Primary outcome measures were calculated blood loss, red blood cell transfusion volume, blood donor exposures, extubation rate, and postoperative complication rate. Secondary outcome measures included intraoperative opioid administration, crystalloid and colloid administration, intraoperative complication rate, and intensive care unit (ICU) and hospital length of stay. Children cared for by the craniofacial team had significantly lower calculated blood loss, reduced red blood cell transfusion volume, fewer blood donor exposures, less crystalloid administration, higher rate of postoperative extubation, fewer postoperative complications, and decreased ICU and hospital length of stay than patients who were managed by noncraniofacial team anesthesiologists. There were no significant differences in demographics, opioid administration, colloid volume administration, or intraoperative complication rates between the 2 groups. Management by a craniofacial team anesthesiologist was associated with improved outcomes in children undergoing major craniofacial reconstructive surgery. While some variability can be attributed to provider-volume relationship, these findings suggest that children may benefit from a subspecialty anesthesia team-based approach for the management of craniofacial surgery, and potentially other similar high-risk cases.