The role of occipital condyle and atlas anomalies on occipital cervical fusion outcomes in Chiari malformation type I with syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium.

OBJECTIVE: Congenital anomalies of the atlanto-occipital articulation may be present in patients with Chiari malformation type I (CM-I). However, it is unclear how these anomalies affect the biomechanical stability of the craniovertebral junction (CVJ) and whether they are associated with an increased incidence of occipitocervical fusion (OCF) following posterior fossa decompression (PFD). The objective of this study was to determine the prevalence of condylar hypoplasia and atlas anomalies in children with CM-I and syringomyelia. The authors also investigated the predictive contribution of these anomalies to the occurrence of OCF following PFD (PFD+OCF). METHODS: The authors analyzed the prevalence of condylar hypoplasia and atlas arch anomalies for patients in the Park-Reeves Syringomyelia Research Consortium database who underwent PFD+OCF. Condylar hypoplasia was defined by an atlanto-occipital joint axis angle (AOJAA) ≥ 130°. Atlas assimilation and arch anomalies were identified on presurgical radiographic imaging. This PFD+OCF cohort was compared with a control cohort of patients who underwent PFD alone. The control group was matched to the PFD+OCF cohort according to age, sex, and duration of symptoms at a 2:1 ratio. RESULTS: Clinical features and radiographic atlanto-occipital joint parameters were compared between 19 patients in the PFD+OCF cohort and 38 patients in the PFD-only cohort. Demographic data were not significantly different between cohorts (p > 0.05). The mean AOJAA was significantly higher in the PFD+OCF group than in the PFD group (144° ± 12° vs 127° ± 6°, p < 0.0001). In the PFD+OCF group, atlas assimilation and atlas arch anomalies were identified in 10 (53%) and 5 (26%) patients, respectively. These anomalies were absent (n = 0) in the PFD group (p < 0.001). Multivariate regression analysis identified the following 3 CVJ radiographic variables that were predictive of OCF occurrence after PFD: AOJAA ≥ 130° (p = 0.01), clivoaxial angle < 125° (p = 0.02), and occipital condyle-C2 sagittal vertical alignment (C-C2SVA) ≥ 5 mm (p = 0.01). A predictive model based on these 3 factors accurately predicted OCF following PFD (C-statistic 0.95). CONCLUSIONS: The authors' results indicate that the occipital condyle-atlas joint complex might affect the biomechanical integrity of the CVJ in children with CM-I and syringomyelia. They describe the role of the AOJAA metric as an independent predictive factor for occurrence of OCF following PFD. Preoperative identification of these skeletal abnormalities may be used to guide surgical planning and treatment of patients with complex CM-I and coexistent osseous pathology.

Impact of Previous Surgery on Success of Magnetic Resonance-guided Laser Interstitial Thermal Therapy (MRgLITT) to Treat Pediatric Epilepsy: An Institutional Experience.

BACKGROUND: There is an emerging role for minimally invasive magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) in the treatment of pediatric epilepsy refractory to medication. To date, predictors of MRgLITT success have not been established in a sizeable singular experience. Correspondingly, the aim of this study was to elucidate if previous surgical history predicts MRgLITT success in this setting. METHODS: A retrospective review was conducted of our MRgLITT procedures for pediatric (patient age <19 years) epilepsy from 2011 to 2020 with documented seizure outcomes at 1 and 2 years after procedure. Categorical and continuous data were compared using χ2 and Student's t test, respectively. RESULTS: A total of 41 patients satisfied all criteria with 16 (39%) female and 25 (61%) male patients. Following MRgLITT, seizure-freedom at 1-year was achieved in 15 (37%) patients. In the cohort, there were 14 (34%) patients who had undergone previous open surgery for epilepsy at mean age of 9.4 ± 5.5 years. Patients with a previous open surgery history were found to statistically experience longer length of hospitalization after MRgLITT (P = 0.04) with a statistically lower proportion of seizure-freedom at 1-year after MRgLITT (14% vs. 48%, P = 0.03). However, there was no difference in the rate of seizure-freedom at 2 years (29% vs. 41%, P = 0.44), as well as no difference in subsequent surgical interventions for seizure management between groups. CONCLUSIONS: Based on our institutional experience, patients with previous open surgery history may experience longer length of hospitalization after MRgLITT for pediatric epilepsy and lesser response in seizure-freedom within the first year but with non-inferior seizure freedom by the second year.

The osteoplastic flap for pediatric temporal lobe epilepsy treatment: step-by-step guide and technical nuances.

The osteoplastic flap is an under-utilized craniotomy approach in pediatric temporal lobe epilepsy treatment. By preserving the myofascial attachment of the temporalis muscle, the flap is allowed the remain vascularized while subdural and intracranial electrodes are in place. The process in which the flap is made and handled throughout this process can be complicated. We herein detail our surgical technique for the osteoplastic flap in the setting of pediatric temporal lobe epilepsy treatment, and highlight the surgical nuances specific to our 2-stage protocol in treating pediatric temporal lobe epilepsy.

Development of an online calculator for the prediction of seizure freedom following pediatric hemispherectomy using the Hemispherectomy Outcome Prediction Scale (HOPS).

OBJECTIVES: Although hemispheric surgeries are among the most effective procedures for drug-resistant epilepsy (DRE) in the pediatric population, there is a large variability in seizure outcomes at the group level. A recently developed HOPS score provides individualized estimation of likelihood of seizure freedom to complement clinical judgement. The objective of this study was to develop a freely accessible online calculator that accurately predicts the probability of seizure freedom for any patient at 1-, 2-, and 5-years post-hemispherectomy. METHODS: Retrospective data of all pediatric patients with DRE and seizure outcome data from the original Hemispherectomy Outcome Prediction Scale (HOPS) study were included. The primary outcome of interest was time-to-seizure recurrence. A multivariate Cox proportional-hazards regression model was developed to predict the likelihood of post-hemispheric surgery seizure freedom at three time points (1-, 2- and 5- years) based on a combination of variables identified by clinical judgment and inferential statistics predictive of the primary outcome. The final model from this study was encoded in a publicly accessible online calculator on the International Network for Epilepsy Surgery and Treatment (iNEST) website (https://hops-calculator.com/). RESULTS: The selected variables for inclusion in the final model included the five original HOPS variables (age at seizure onset, etiologic substrate, seizure semiology, prior non-hemispheric resective surgery, and contralateral fluorodeoxyglucose-positron emission tomography [FDG-PET] hypometabolism) and three additional variables (age at surgery, history of infantile spasms, and magnetic resonance imaging [MRI] lesion). Predictors of shorter time-to-seizure recurrence included younger age at seizure onset, prior resective surgery, generalized seizure semiology, FDG-PET hypometabolism contralateral to the side of surgery, contralateral MRI lesion, non-lesional MRI, non-stroke etiologies, and a history of infantile spasms. The area under the curve (AUC) of the final model was 73.0%. SIGNIFICANCE: Online calculators are useful, cost-free tools that can assist physicians in risk estimation and inform joint decision-making processes with patients and families, potentially leading to greater satisfaction. Although the HOPS data was validated in the original analysis, the authors encourage external validation of this new calculator.

Machine learning models for predicting seizure outcome after MR-guided laser interstitial thermal therapy in children.

OBJECTIVE: MR-guided laser interstitial thermal therapy (MRgLITT) is associated with lower seizure-free outcome but better safety profile compared to open surgery. However, the predictors of seizure freedom following MRgLITT remain uncertain. This study aimed to use machine learning to predict seizure-free outcome following MRgLITT and to identify important predictors of seizure freedom in children with drug-resistant epilepsy. METHODS: This multicenter study included children treated with MRgLITT for drug-resistant epilepsy at 13 epilepsy centers. The authors used clinical data, diagnostic investigations, and ablation features to predict seizure-free outcome at 1 year post-MRgLITT. Patients from 12 centers formed the training cohort, and patients in the remaining center formed the testing cohort. Five machine learning algorithms were developed on the training data by using 10-fold cross-validation, and model performance was measured on the testing cohort. The models were developed and tested on the complete feature set. Subsequently, 3 feature selection methods were used to identify important predictors. The authors then assessed performance of the parsimonious models based on these important variables. RESULTS: This study included 268 patients who underwent MRgLITT, of whom 44.4% had achieved seizure freedom at 1 year post-MRgLITT. A gradient-boosting machine algorithm using the complete feature set yielded the highest area under the curve (AUC) on the testing set (AUC 0.67 [95% CI 0.50-0.82], sensitivity 0.71 [95% CI 0.47-0.88], and specificity 0.66 [95% CI 0.50-0.81]). Logistic regression, random forest, support vector machine, and neural network yielded lower AUCs (0.58-0.63) compared to the gradient-boosting machine but the findings were not statistically significant (all p > 0.05). The 3 feature selection methods identified video-EEG concordance, lesion size, preoperative seizure frequency, and number of antiseizure medications as good prognostic features for predicting seizure freedom. The parsimonious models based on important features identified by univariate feature selection slightly improved model performance compared to the complete feature set. CONCLUSIONS: Understanding the predictors of seizure freedom after MRgLITT will assist with prognostication.

Added value of corpus callosotomy following vagus nerve stimulation in children with Lennox-Gastaut syndrome: A multicenter, multinational study.

OBJECTIVE: Lennox-Gastaut syndrome (LGS) is a severe form of epileptic encephalopathy, presenting during the first years of life, and is very resistant to treatment. Once medical therapy has failed, palliative surgeries such as vagus nerve stimulation (VNS) or corpus callosotomy (CC) are considered. Although CC is more effective than VNS as the primary neurosurgical treatment for LGS-associated drop attacks, there are limited data regarding the added value of CC following VNS. This study aimed to assess the effectiveness of CC preceded by VNS. METHODS: This multinational, multicenter retrospective study focuses on LGS children who underwent CC before the age of 18 years, following prior VNS, which failed to achieve satisfactory seizure control. Collected data included epilepsy characteristics, surgical details, epilepsy outcomes, and complications. The primary outcome of this study was a 50% reduction in drop attacks. RESULTS: A total of 127 cases were reviewed (80 males). The median age at epilepsy onset was 6 months (interquartile range [IQR] = 3.12-22.75). The median age at VNS surgery was 7 years (IQR = 4-10), and CC was performed at a median age of 11 years (IQR = 8.76-15). The dominant seizure type was drop attacks (tonic or atonic) in 102 patients. Eighty-six patients underwent a single-stage complete CC, and 41 an anterior callosotomy. Ten patients who did not initially have a complete CC underwent a second surgery for completion of CC due to seizure persistence. Overall, there was at least a 50% reduction in drop attacks and other seizures in 83% and 60%, respectively. Permanent morbidity occurred in 1.5%, with no mortality. SIGNIFICANCE: CC is vital in seizure control in children with LGS in whom VNS has failed. Surgical risks are low. A complete CC has a tendency toward better effectiveness than anterior CC for some seizure types.

Treatment of Chiari malformations with craniovertebral junction anomalies: Where do we stand today?

Background: Chiari malformation type 1 (CM-1) is characterized by cerebellar tonsil herniation through the foramen magnum and can be associated with additional craniovertebral junction anomalies (CVJA). The pathophysiology and treatment for CM-1 with CVJA (CM-CVJA) is debated. Objective: To evaluate the trends and outcomes of surgical interventions for patients with CM-CVJA. Methods: A systematic review of the literature was performed to obtain articles describing surgical interventions for patients with CM-CVJA. Articles included were case series describing surgical approach; reviews were excluded. Variables evaluated included patient characteristics, approach, and postoperative outcomes. Results: The initial query yielded 403 articles. Twelve articles, published between 1998-2020, met inclusion criteria. From these included articles, 449 patients underwent surgical interventions for CM-CVJA. The most common CVJAs included basilar invagination (BI) (338, 75.3%), atlantoaxial dislocation (68, 15.1%) odontoid process retroflexion (43, 9.6%), and medullary kink (36, 8.0%). Operations described included posterior fossa decompression (PFD), transoral (TO) decompression, and posterior arthrodesis with either occipitocervical fusion (OCF) or atlantoaxial fusion. Early studies described good results using combined ventral and posterior decompression. More recent articles described positive outcomes with PFD or posterior arthrodesis in combination or alone. Treatment failure was described in patients with PFD alone that later required posterior arthrodesis. Additionally, reports of treatment success with posterior arthrodesis without PFD was seen. Conclusion: Patients with CM-CVJA appear to benefit from posterior arthrodesis with or without decompressive procedures. Further definition of the pathophysiology of craniocervical anomalies is warranted to identify patient selection criteria and ideal level of fixation.

"A Simplified Approach for Surgical Correction of Vertical Orbital Dystopia: A 45-year Retrospective Cohort Study."

INTRODUCTION: Vertical Orbital Dystopia (VOD) results in significant facial asymmetry, psychological distress, and poor quality of life in affected patients. The traditional approach (TA) for surgical correction has entailed a standard frontal craniotomy along with circumferential orbital osteotomy, vertical translocation of the orbit, and bone grafting to the lower maxilla. Caution has been expressed regarding its invasive transcranial nature. In this report, we describe the limited approach (LA) for simplified surgical correction of VOD, which obviates the need for a standard frontal craniotomy. METHODS: A 45-year retrospective review was conducted of all patients that underwent surgical correction of VOD, as performed by a single surgeon. Demographic details, procedural characteristics, and complications were compared between patients who were corrected by the TA and those who were corrected by the LA. Complications were defined as CSF leak, infection of the frontal bone, permanent diplopia, permanent ptosis, sudden-onset vision loss, persistent asymmetry, and surgical revision. RESULTS: Forty patients met inclusion criteria for correction of true VOD, of which 18 underwent the TA and 22 underwent the LA. Mean length of hospital stay was 5.3±2.3 days and 4.0±1.5 days for the TA and LA cohorts, respectively. Mean follow-up time was 4.9±7.5 years for the TA and 2.6±3.3 years for the LA. The only reported complications were persistent asymmetry in 2 patients in the TA cohort with one patient requiring surgical revision due to undercorrection, while the LA cohort exhibited no postoperative asymmetry or need for surgical revision. CONCLUSIONS: Both the TA and LA are effective for surgical correction of VOD. The limited craniotomy of the LA reduces exposure of intracranial structures and adequately achieves postoperative symmetry.

Chiari I malformation management in patients with heritable connective tissue disorders.

Background: Chiari malformation type I (CMI) is relatively common neurosurgical condition typically treated with posterior fossa decompression. However, the management of CMI in patients with heritable connective tissue disorders (CTDs), such as Ehlers-Danlos Syndrome, Marfan Syndrome, or Osteogenesis Imperfecta, involves a unique set of perioperative challenges. Objective: This study aims to define the demographic information, comorbidities, and perioperative course of patients with concomitant CMI and CTD. Methods: Patients with CMI admitted for surgical decompression from 2008 to 2015 were captured using the National Inpatient Sample (NIS). Information was collected based on ICD-9 codes. Descriptive and regression analyses were performed in SPSS (version 26). Results: 38,169 CMI patients, 353 of whom had CTD (0.92%), were identified. CMI patients with CTD were more likely to be female (p < 0.001) and present during teenage (p = 0.033) or young adult years (p < 0.001). They had more chronic issues (p < 0.001): systemic comorbidities include postural orthostatic tachycardia syndrome, cardiac dysrhythmias, and gastroparesis (all p < 0.001). CNS comorbidities include migraine, tethered spinal cord, and epilepsy (all p < 0.001). They have increased joint instability (both p < 0.001), as well as craniocervical instability (CCI). More posterior cervical fusion surgeries and application of cervical halo devices were seen during the same inpatient stay (both p < 0.001). Conclusions: Patients with concurrent CTD and CMI were more likely to present with complex Chiari and associated CCI. They were also younger, more often female, and had more systemic, CNS, and joint abnormalities. As such, preoperative recognition of an underlying CTD is imperative to achieve optimal outcomes in this patient population.

An Oncoplastic Approach to Primary Pediatric Pterygomaxillary Osteosarcoma.

Osteosarcomas arising within the pterygomaxillary/infratemporal fossa region are rare among the pediatric population. Survival rates are most influenced by tumor resection with negative margins, which can be dependent on surgical accessibility of the tumor site. The pterygomaxillary/infratemporal fossa location poses several challenges to safe and adequate tumor resection, including proximity of the facial nerve and great vessels and scarring associated with traditional transfacial approaches. In this article, we present the case of a 6-year-old boy with an osteosarcoma of the left pterygomaxillary/infratemporal fossa region successfully managed with an "oncoplastic" approach, incorporating the use of CAD/CAM and mixed reality technologies.

The natural history of postoperative hydrocephalus after pediatric hemispherectomy for medically refractory epilepsy: an institutional experience.

OBJECTIVE: Hemispherectomy is a complex surgical intervention for medically refractory epilepsy, and its surgical sequelae continue to be defined. The incidence, timing, and predictors of postoperative hydrocephalus are not well understood. Correspondingly, the aim of this study was to define the natural history of the development of hydrocephalus after hemispherectomy based on the authors' institutional experience. METHODS: The authors performed a retrospective review of their departmental database for all relevant cases between 1988 and 2018. Demographic and clinical results were abstracted and analyzed using regression analyses to identify predictors of postoperative hydrocephalus. RESULTS: Of the 114 patients who satisfied selection criteria, there were 53 females (46%) and 61 males (53%) with mean ages of 2.2 and 6.5 years at first seizure and at hemispherectomy, respectively. There were 16 patients (14%) with a history of previous seizure surgery. In terms of surgery, the mean estimated blood loss was 441 ml, with a mean operative time of 7 hours, and 81 patients (71%) required intraoperative transfusions. A planned postoperative external ventricular drain (EVD) was placed in 38 patients (33%). The most common procedural complications were infection and hematoma, occurring in 7 patients (6%) each. Overall, there were 13 patients (11%) with postoperative hydrocephalus requiring permanent CSF diversion, occurring at a median of 1 year (range 0.1-5 years) after surgery. On multivariable analysis, a postoperative EVD (OR 0.12, p < 0.01) was significantly associated with a decreased likelihood of postoperative hydrocephalus, whereas previous surgery history (OR 4.32, p = 0.03) and postoperative infection complication (OR 5.14, p = 0.04) were significantly associated with increased likelihood of postoperative hydrocephalus. CONCLUSIONS: Postoperative hydrocephalus mandating permanent CSF diversion following hemispherectomy can be expected in approximately 1 in 10 cases, presenting months after surgery on average. A postoperative EVD appears to reduce this likelihood, whereas postoperative infection and previous history of seizure surgery were shown to statistically increase this likelihood. These parameters should be carefully considered in the management of pediatric hemispherectomy for medically refractory epilepsy.

Impact of intraventricular hemorrhage symmetry on endoscopic third ventriculostomy with choroid plexus cauterization for posthemorrhagic hydrocephalus: an institutional experience of 50 cases.

OBJECTIVE: The success rate of endoscopic third ventriculostomy with choroid plexus cauterization (ETV/CPC) in the management of posthemorrhagic hydrocephalus (PHH) following intraventricular hemorrhage (IVH) in infants is not well defined. Furthermore, parameters of IVH at initial presentation have not been tested for predictive associations of ETV/CPC success in this setting. The authors sought to summarize their institutional outcomes to identify possible predictors of ETV/CPC success within this niche. METHODS: A retrospective review was conducted of all ETV/CPC procedures performed at the authors' institution for PHH between 2011 and 2021. Patients were screened against a set of selection criteria including follow-up time of at least 6 months. Associations with ETV/CPC failure were evaluated using regression and Kaplan-Meier analyses. RESULTS: A total of 50 patients satisfied all criteria. There were 32 (64%) male and 18 (36%) female patients with a mean gestational birth age of 26 weeks. The presenting IVH was symmetric in 30 (60%) and asymmetric in 20 (40%) patients, and the maximum IVH grade was IV in 30 (60%) patients overall. Six months after the procedure, ETV/CPC success was seen in 18 (36%) patients and failure in 32 (64%) patients. The median overall follow-up was 42 months, at which point ETV/CPC success was observed in 11 (22%) patients and ETV/CPC failure in 39 (78%) patients. Regression analyses indicated that radiological IVH symmetry was a statistically significant predictor of ETV/CPC failure at 6 months (OR 3.46, p = 0.04) and overall (OR 5.33, p = 0.03). Overall rates of failure were 89% versus 62% (p = 0.02) when comparing symmetric versus asymmetric IVH patients, and time to failure occurred at median times of 1.4 versus 6.5 months (p = 0.03) after the initial procedure. Higher maximum IVH grade and younger age at initial ETV/CPC only trended toward increased failure rates. When the etiology component of the ETV Success Score was adjusted such that symmetric IVH was scored 0, the area under the curve for failure at 6 months increased from 0.58 to 0.69. CONCLUSIONS: Overall, approximately 1 in 5 infants with PHH can expect to not require further intervention following ETV/CPC. The authors demonstrate that IVH symmetry is statistically predictive of ETV/CPC failure in this setting independent of all other parameters, where PHH infants with symmetric IVH are more likely to experience failure, and sooner, than PHH infants with asymmetric IVH. When discussing possible success rates of ETV/CPC for PHH, IVH symmetry should be considered.

Seizure outcome of pediatric magnetic resonance-guided laser interstitial thermal therapy versus open surgery: A matched noninferiority cohort study.

OBJECTIVE: Minimally invasive magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has been proposed as an alternative to open epilepsy surgery, to address concerns regarding the risk of open surgery. Our primary hypothesis was that seizure freedom at 1 year after MRgLITT is noninferior to open surgery in children with drug-resistant epilepsy (DRE). The secondary hypothesis was that MRgLITT has fewer complications and shorter hospitalization than surgery. The primary objective was to compare seizure outcome of MRgLITT to open surgery in children with DRE. The secondary objective was to compare complications and length of hospitalization of the two treatments. METHODS: This retrospective multicenter cohort study included children with DRE treated with MRgLITT or open surgery with 1-year follow-up. Exclusion criteria were corpus callosotomy, neurostimulation, multilobar or hemispheric surgery, and lesion with maximal dimension > 60 mm. MRgLITT patients were propensity matched to open surgery patients. The primary outcome was seizure freedom at 1 year posttreatment. The difference in seizure freedom was compared using noninferiority test, with noninferiority margin of -10%. The secondary outcomes were complications and length of hospitalization. RESULTS: One hundred eighty-five MRgLITT patients were matched to 185 open surgery patients. Seizure freedom at 1 year follow-up was observed in 89 of 185 (48.1%) MRgLITT and 114 of 185 (61.6%) open surgery patients (difference = -13.5%, one-sided 97.5% confidence interval = -23.8% to ∞, pNoninferiority  = .79). The lower confidence interval boundary of -23.8% was below the prespecified noninferiority margin of -10%. Overall complications were lower in MRgLITT compared to open surgery (10.8% vs. 29.2%, respectively, p < .001). Hospitalization was shorter for MRgLITT than open surgery (3.1 ± 2.9 vs. 7.2 ± 6.1 days, p < .001). SIGNIFICANCE: Seizure outcome of MRgLITT at 1 year posttreatment was inferior to open surgery. However, MRgLITT has the advantage of better safety profile and shorter hospitalization. The findings will help counsel children and parents on the benefits and risks of MRgLITT and contribute to informed decision-making on treatment options.

Repeat surgery for pediatric epilepsy: a systematic review and meta-analysis of resection and disconnection approaches.

OBJECTIVE: Resection and disconnection surgeries for epilepsy in the pediatric demographic (patients ≤ 18 years of age) are two separate, definitive intervention options in medically refractory cases. Questions remain regarding the role of surgery when seizures persist after an initial incomplete surgery. The aim of this study was to review the contemporary literature and summarize the metadata on the outcomes of repeat surgery in this specific demographic. METHODS: Searches of seven electronic databases from inception to July 2022 were conducted using PRISMA guidelines. Articles were screened using prespecified criteria. Metadata from the articles were abstracted and pooled by random-effects meta-analysis of proportions. RESULTS: Eleven studies describing 12 cohorts satisfied all criteria, reporting outcomes of 170 pediatric patients with epilepsy who underwent repeat resection or disconnection surgery. Of these patients, 55% were male, and across all studies, median ages at initial and repeat surgeries were 7.2 and 9.4 years, respectively. The median follow-up duration after repeat surgery was 47.7 months. The most commonly reported etiology for epilepsy was cortical dysplasia. Overall, the estimated incidence of complete seizure freedom (Engel class I) following repeat surgery was 48% (95% CI 40%-56%, p value for heterogeneity = 0.93), and the estimated incidence of postoperative complications following repeat surgery was 25% (95% CI 12%-39%, p = 0.04). There were six cohorts each that described outcomes for repeat resection and repeat disconnection surgeries. There was no statistical difference between these two subgroups with respect to estimated incidence of complete seizure freedom (p value for interaction = 0.92), but postoperative complications were statistically more common following repeat resection (p ≤ 0.01). CONCLUSIONS: For both resection and disconnection surgeries, repeat epilepsy surgery in children is likely to confer complete seizure freedom in approximately half of the patients who experience unsuccessful initial incomplete epilepsy surgery. More data are needed to elucidate the impact on efficacy based on surgical approach selection. Judicious discussion and planning between the patient, family, and a multidisciplinary team of epilepsy specialists is recommended to optimize expectations and outcomes in this setting.

A snapshot of contemporary leadership at pediatric neurosurgery fellowships.

OBJECTIVE: Many pathways to positions of leadership exist within pediatric neurological surgery. The authors sought to investigate common trends in leadership among pediatric neurosurgery fellowship directors (FDs) and describe how formalized pediatric neurosurgical training arrived at its current state. METHODS: Fellowship programs were identified using the Accreditation Council for Pediatric Neurosurgery Fellowships website. Demographic, training, membership, and research information was collected via email, telephone, curricula vitae, and online searches. RESULTS: The authors' survey was sent to all 35 identified FDs, and 21 responses were received. Response data were supplemented with curricula vitae and online data prior to analysis. FDs were predominantly male, self-identified predominantly as Caucasian, and had a mean age of 53 years. The mean duration from residency graduation until FD appointment was 13.4 years. The top training programs to produce future FDs were New York University and Washington University in St. Louis (residency) and Washington University in St. Louis (fellowship). CONCLUSIONS: This study characterizes the current state of pediatric neurosurgery fellowship program leadership. The data serve as an important point of reference to compare with future leadership as well as contrast with neurosurgery and other surgical disciplines in general.

Incidence, follow-up, and postnatal clinical progress of children with central nervous system anomalies on fetal MRI.

OBJECTIVE: MRI is increasingly employed to assess intrauterine fetal anomalies. Central nervous system (CNS) anomalies are common structural conditions that warrant evaluation with fetal MRI and subsequent prenatal consultation with a pediatric neurosurgeon. As the use of fetal MRI increases, there is greater impetus to understand the most common CNS structural anomalies diagnosed in utero, as well as their natural histories. METHODS: The authors performed a single-center retrospective review of fetal MRI evaluations performed between January 2012 and December 2020. Children who underwent both prenatal and postnatal neurosurgical evaluations of CNS anomalies were included. Specific CNS anomalies on fetal MRI, associated extra-CNS findings, and suspicion for genetic abnormality or syndromes were noted. Postnatal clinical status and interventions were assessed. RESULTS: Between January 2012 and December 2020, a total of 469 fetal MRI evaluations were performed; of these, 114 maternal-fetal pairs had CNS anomalies that warranted prenatal consultation and postnatal pediatric neurosurgical follow-up. This cohort included 67 male infants (59%), with a mean ± SD follow-up of 29.8 ± 25.0 months after birth. Fetal MRI was performed at 27.3 ± 5.8 weeks of gestational age. The most frequently reported CNS abnormalities were ventriculomegaly (57%), agenesis or thinning of the corpus callosum (33%), Dandy-Walker complex (DWC) (21%), neuronal migration disorders (18%), and abnormalities of the septum pellucidum (17%). Twenty-one children (18%) required neurosurgical intervention at a mean age of 2.4 ± 3.7 months. The most common surgical conditions included myelomeningocele, moderate to severe ventriculomegaly, encephalocele, and arachnoid cyst. Corpus callosum agenesis or thinning was associated with developmental delay (p = 0.02) and systemic anomalies (p = 0.05). The majority of prenatal patients referred for DWC had Dandy-Walker variants that did not require surgical intervention. CONCLUSIONS: The most common conditions for prenatal neurosurgical assessment were ventriculomegaly, corpus callosum anomaly, and DWC, whereas the most common surgical conditions were myelomeningocele, hydrocephalus, and arachnoid cyst. Only 18% of prenatal neurosurgical consultations resulted in surgical intervention during infancy. The majority of referrals for prenatal mild ventriculomegaly and DWC were not associated with developmental or surgical sequelae. Patients with corpus callosum abnormalities should be concurrently referred to a neurologist for developmental assessments.

Development and validation of machine learning models for prediction of seizure outcome after pediatric epilepsy surgery.

OBJECTIVE: There is substantial variability in reported seizure outcome following pediatric epilepsy surgery, and lack of individualized predictive tools that could evaluate the probability of seizure freedom postsurgery. The aim of this study was to develop and validate a supervised machine learning (ML) model for predicting seizure freedom after pediatric epilepsy surgery. METHODS: This is a multicenter retrospective study of children who underwent epilepsy surgery at five pediatric epilepsy centers in North America. Clinical information, diagnostic investigations, and surgical characteristics were collected, and used as features to predict seizure-free outcome 1 year after surgery. The dataset was split randomly into 80% training and 20% testing data. Thirty-five combinations of five feature sets with seven ML classifiers were assessed on the training cohort using 10-fold cross-validation for model development. The performance of the optimal combination of ML classifier and feature set was evaluated in the testing cohort, and compared with logistic regression, a classical statistical approach. RESULTS: Of the 801 patients included, 61.3% were seizure-free 1 year postsurgery. During model development, the best combination was XGBoost ML algorithm with five features from the univariate feature set, including number of antiseizure medications, magnetic resonance imaging lesion, age at seizure onset, video-electroencephalography concordance, and surgery type, with a mean area under the curve (AUC) of .73 (95% confidence interval [CI] = .69-.77). The combination of XGBoost and univariate feature set was then evaluated on the testing cohort and achieved an AUC of .74 (95% CI = .66-.82; sensitivity = .87, 95% CI = .81-.94; specificity = .58, 95% CI = .47-.71). The XGBoost model outperformed the logistic regression model (AUC = .72, 95% CI = .63-.80; sensitivity = .72, 95% CI = .63-.82; specificity = .66, 95% CI = .53-.77) in the testing cohort (p = .005). SIGNIFICANCE: This study identified important features and validated an ML algorithm, XGBoost, for predicting the probability of seizure freedom after pediatric epilepsy surgery. Improved prognostication of epilepsy surgery is critical for presurgical counseling and will inform treatment decisions.

Complications and outcomes of posterior fossa decompression with duraplasty versus without duraplasty for pediatric patients with Chiari malformation type I and syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium.

OBJECTIVE: The aim of this study was to determine differences in complications and outcomes between posterior fossa decompression with duraplasty (PFDD) and without duraplasty (PFD) for the treatment of pediatric Chiari malformation type I (CM1) and syringomyelia (SM). METHODS: The authors used retrospective and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM1-SM who received PFD or PFDD and had at least 1 year of follow-up data. Preoperative, treatment, and postoperative characteristics were recorded and compared between groups. RESULTS: A total of 692 patients met the inclusion criteria for this database study. PFD was performed in 117 (16.9%) and PFDD in 575 (83.1%) patients. The mean age at surgery was 9.86 years, and the mean follow-up time was 2.73 years. There were no significant differences in presenting signs or symptoms between groups, although the preoperative syrinx size was smaller in the PFD group. The PFD group had a shorter mean operating room time (p < 0.0001), fewer patients with > 50 mL of blood loss (p = 0.04), and shorter hospital stays (p = 0.0001). There were 4 intraoperative complications, all within the PFDD group (0.7%, p > 0.99). Patients undergoing PFDD had a 6-month complication rate of 24.3%, compared with 13.7% in the PFD group (p = 0.01). There were no differences between groups for postoperative complications beyond 6 months (p = 0.33). PFD patients were more likely to require revision surgery (17.9% vs 8.3%, p = 0.002). PFDD was associated with greater improvements in headaches (89.6% vs 80.8%, p = 0.04) and back pain (86.5% vs 59.1%, p = 0.01). There were no differences between groups for improvement in neurological examination findings. PFDD was associated with greater reduction in anteroposterior syrinx size (43.7% vs 26.9%, p = 0.0001) and syrinx length (18.9% vs 5.6%, p = 0.04) compared with PFD. CONCLUSIONS: PFD was associated with reduced operative time and blood loss, shorter hospital stays, and fewer postoperative complications within 6 months. However, PFDD was associated with better symptom improvement and reduction in syrinx size and lower rates of revision decompression. The two surgeries have low intraoperative complication rates and comparable complication rates beyond 6 months.

Intracranial aneurysms in the infant population: an institutional case series and individual participant data meta-analysis.

OBJECTIVE: Infantile intracranial aneurysms are exceedingly rare. The goal of this study was to evaluate an institutional case series of infantile intracranial aneurysms, as well as those reported in the contemporary literature, to determine their demographics, presentation, management, and long-term outcome. METHODS: A comprehensive literature review from 1980 to 2020 was performed to identify individual cases of intracranial aneurysms in the infantile population ≤ 2 years of age. Additional cases from the authors' institution were identified during the same time period. An individual participant data meta-analysis (IPDMA) was performed, abiding by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Patient demographic, radiographic, and clinical information was obtained. Descriptive statistical data were recorded, and multivariate logistic regression analyses were performed. RESULTS: Patient data were obtained for 133 patients from 87 articles in the literature. Ten additional patients at the authors' institution were also identified, for a total of 143 patients included in the IPDMA. The majority (72.7%) of this cohort consisted of idiopathic aneurysms, while 13.3% were posttraumatic pseudoaneurysms, 9.8% were infectious mycotic aneurysms, and 4.2% were aneurysms associated with a systemic connective tissue disorder or vasculitis. The mean age at presentation was 6.6 months. The majority of infants (97.9%) harbored only 1 aneurysm, and hemorrhage was the most common presenting feature (78.3%). The mean aneurysm size was 14.4 mm, and giant aneurysms ≥ 25 mm comprised 12.9% of the cohort. Most aneurysms occurred in the anterior circulation (80.9%), with the middle cerebral artery (MCA) being the most commonly affected vessel (51.8%). Management strategies included open surgical aneurysm ligation (54.0%), endovascular treatment (35.0%), surgical decompression without aneurysm treatment (4.4%), and medical supportive management only (13.9%). Surgical aneurysm ligation was more commonly performed for MCA and anterior cerebral artery aneurysms (p = 0.004 and p = 0.015, respectively), while endovascular techniques were favored for basilar artery aneurysms (p = 0.042). The mean follow-up period was 29.9 months; 12.4% of the cohort died, and 67.0% had a favorable outcome (Glasgow Outcome Scale score of 5). CONCLUSIONS: This study is, to the authors' knowledge, the largest analysis of infantile intracranial aneurysms to date. The majority were idiopathic aneurysms involving the anterior circulation. Surgical and endovascular techniques yielded equally favorable outcomes in this cohort. Long-term outcomes in the infantile population compared favorably to outcomes in adults.