Long-term outcomes of deep pediatric arteriovenous malformations.

OBJECTIVE: Multimodality treatment has been shown to be the optimal management strategy for pediatric arteriovenous malformations (AVMs). Deep AVMs represent a subset of AVMs for which optimal management may be achieved with a combination of radiosurgery and highly selective embolization, in the absence of compelling features requiring operative intervention. The objective of this study was to identify predictors of good functional outcomes in pediatric patients with deep AVMs. METHODS: A retrospective cohort study of the outcomes of 79 patients with deep AVMs from January 1988 through December 2021 was performed. Deep AVMs were defined as those with the majority of the nidus centered in the basal ganglia, thalamus, or brainstem. Collected data included patient demographics and presenting symptoms, presenting modified Rankin Scale (mRS) score, radiographic findings and outcomes, management strategy, complications, and clinical outcomes as indicated by follow-up mRS score. A good outcome was defined as a follow-up mRS score ≤ 2, while a poor outcome was defined as a follow-up mRS score ≥ 3. Statistical analysis was performed to identify factors associated with functional outcomes. RESULTS: With a mean follow-up duration of 85.6 months, there was a 72.2% angiographic obliteration rate, with 75.9% of patients having a good clinical outcome (mRS score ≤ 2). Presenting symptoms and radiographic characteristics were not significantly associated with long-term functional outcomes. There was a significantly higher rate of posttreatment hemorrhage in patients with a poor versus good outcome (11.8% vs 0%, p = 0.010). On multivariate logistic regression analysis, poor long-term functional outcome was only associated with poor presenting mRS score (p = 0.002). CONCLUSIONS: Satisfactory angiographic obliteration rates and good long-term functional outcomes can be achieved for deep AVMs, with stereotactic radiosurgery as the cornerstone of multimodality treatment.

Relationship of cervical soft tissue injury and surgical predication following pediatric cervical spinal trauma and its sequelae on long-term neurologic outcome.

Within the sample of 181 patients with cervical CT, CT identified unstable injury with a sensitivity of 100% and specificity of 95%. CT identified operable injury at the CCJ with 86% sensitivity and 91% specificity. CT was considered the gold standard for identification of fractures. Together, the presence of CT imaging suggestive of unstable injury or persistent neurologic complaint had a 100% sensitivity and 81% specificity. Finally, across all patients MRI had 100% sensitivity and 89% specificity for detection of unstable injury requiring surgery.

Treatment of hydrocephalus following posterior fossa tumor resection: a multicenter collaboration from the Hydrocephalus Clinical Research Network.

OBJECTIVE: Persistent hydrocephalus following posterior fossa brain tumor (PFBT) resection is a common cause of morbidity in pediatric brain tumor patients, for which the optimal treatment is debated. The purpose of this study was to compare treatment outcomes between VPS and ETV in patients with persistent hydrocephalus following surgical resection of a PFBT. METHODS: A post-hoc analysis was performed of the Hydrocephalus Clinical Research Network (HCRN) prospective observational study evaluating VPS and ETV for pediatric patients. Children who experienced hydrocephalus secondary to PFBT from 2008 to 2021 were included. Primary outcomes were VPS/ETV treatment failure and time-to-failure (TTF). RESULTS: Among 241 patients, the VPS (183) and ETV (58) groups were similar in age, extent of tumor resection, and preoperative ETV Success Score. There was no difference in overall treatment failure between VPS and ETV (33.9% vs 31.0%, p = 0.751). However, mean TTF was shorter for ETV than VPS (0.45 years vs 1.30 years, p = 0.001). While major complication profiles were similar, compared to VPS, ETV patients had relatively higher incidence of minor CSF leak (10.3% vs. 1.1%, p = 0.003) and pseudomeningocele (12.1% vs 3.3%, p = 0.02). No ETV failures were identified beyond 3 years, while shunt failures occurred beyond 5 years. Shunt infections occurred in 5.5% of the VPS cohort. CONCLUSIONS: ETV and VPS offer similar overall success rates for PFBT-related postoperative hydrocephalus. ETV failure occurs earlier, while susceptibility to VPS failure persists beyond 5 years. Tumor histology and grade may be considered when selecting the optimal means of CSF diversion.

Risk Factors in a Pediatric Population for Postoperative Intracranial Infection Following Endoscopic Endonasal Skull Base Surgery and the Role of Antibiotic Prophylaxis.

BACKGROUND: Endoscopic endonasal skull base surgery (EESBS) is performed through a non-sterile corridor. Intracranial infection rates in a pediatric population have not been extensively studied and the exact effect of antibiotic prophylaxis on rates of infection after EESBS in pediatric patients remains unclear. OBJECTIVE: The purpose of our study is to investigate risk factors for postoperative intracranial infection during EESBS in a pediatric population and help elucidate the role of antibiotic prophylaxis. METHODS: We conducted a retrospective chart review of 99 consecutive patients under the age of 18 who underwent EESBS at our institution from 2013 to 2021. Centers for Disease Control and Prevention/National Healthcare Safety Network criteria for diagnosis of meningitis were used to identify postoperative intracranial infections. RESULTS: The average age was 12.3 years (range 1.6-18) with 66 male patients and 33 female patients. 49 patients had an intraoperative cerebrospinal fluid (CSF) leak, of which 4 had a postoperative CSF leak. We identified 3 postoperative intracranial infections (3%), which were all meningitis cases. The infection rate was 6% (3/49) among those with intraoperative CSF leaks. All patients with meningitis had a postoperative CSF leak. All infections were transclival approaches (2 chordoma and 1 neurenteric cyst). CONCLUSION: This investigation represents one of the largest pediatric endoscopic skull base surgery cohorts. EESBS is safe to perform in pediatric populations, but transclival approaches and postoperative CSF leaks are risk factors for postoperative meningitis.

Dural Sealants Do Not Reduce Postoperative Cerebrospinal Fluid Leak after Endoscopic Endonasal Skull Base Surgery.

Introduction The application of cranial tissue sealants to assist with postoperative closure is widespread, but data are lacking regarding its utility in endoscopic endonasal surgery (EEA). A prospective study was conducted to assess the effect of sealant usage on postoperative cerebrospinal fluid (CSF) leak rate following standard reconstruction. Methods A prospective trial of sealant usage after endoscopic endonasal skull base surgery was performed from May 2016 to June 2019 at a tertiary referral cranial base center. This study enrolled 300 consecutive adult and pediatric patients with skull base pathology who underwent EES in which an intraoperative CSF leak occurred. Patients were sequentially stratified into equally sized groups who did or did not receive sealant as part of their reconstruction. Results Three hundred consecutive adult and pediatric patients were enrolled in the study and had a confirmed intraoperative CSF leak. The intervention cohort with sealant (first 150 patients) had 21 postoperative CSF leaks (14% rate) compared with 9 postoperative CSF leaks (6% rate) in the control group without sealant ( p = 0.02). On multivariate analysis, sealant usage was associated with a higher rate of postoperative CSF leak (odds ratio [OR] = 2.7; p = 0.025). Male gender (OR = 2.4; p = 0.04) and high-flow intraoperative CSF leak (OR = 3.1; p = 0.038) were also found to be associated with postoperative CSF leak. Conclusion Among all patients undergoing EES with an intraoperative CSF leak, the addition of sealant to standard closure techniques did not reduce the rate of postoperative CSF leaks.

Endoscopic Techniques in Vascular Neurosurgery.

This section reviews the selection criteria and best practices for endoscopic cerebrovascular surgery, focusing on purely endoscopic endonasal approaches. Although these approaches still play a limited role in open vascular neurosurgery, they offer a robust and potentially safer technique for establishing visualization and vascular control of particular, well-selected pathologies, such as aneurysms of the proximal circulation; this requires strong, multidisciplinary experience with endoscopic anatomy and surgical technique, advanced reconstruction techniques, and instruments designed to be maneuvered within this relatively novel corridor and application.

The Eyebrow Approach for the Management of Pediatric Frontal Epidural Abscesses Secondary to Diffuse Sinusitis.

BACKGROUND: Minimally invasive approaches to the anterior cranial fossa have evolved over the past few decades. The management of frontal epidural abscesses (EDAs) secondary to diffuse sinusitis in the pediatric population using minimally invasive techniques is scarcely reported in the literature. Herein, we report the utilization of a minimally invasive eyebrow approach for multidisciplinary concurrent evacuation of frontal EDA secondary to diffuse sinusitis and trephination of the frontal sinus in three pediatric patients. CASE REPORTS: Three pediatric patients presented to the emergency room with severe headaches, visual changes, somnolence, and significant facial and periorbital swelling. Imaging revealed diffuse sinusitis with focal frontal epidural extension. In all cases, progressive clinical deterioration along with the radiographic findings mandated urgent surgical intervention. The eyebrow approach allowed for concomitant evacuation of the frontal EDA and trephination of the frontal sinus followed by functional endoscopic sinus surgery in the same setting. All patients tolerated the procedure well with complete resolution of their symptoms at the completion of antibiotic therapy and complete resolution of the EDA. CONCLUSION: The eyebrow approach is a minimally invasive technique that should be considered as part of the armamentarium in the management of select EDA in the pediatric population. It allows for multidisciplinary collaboration between neurosurgeons and otolaryngologists for concomitant evacuation of the EDA and trephination of the frontal sinus. This approach is a feasible, safe, and effective minimally invasive technique that can be employed for the management of EDA secondary to diffuse sinusitis in the pediatric population.

Acquired Chiari Type I Malformation Associated with Type IV Dural Arteriovenous Fistula: Case Report.

BACKGROUND: Chiari malformations, usually congenital, can rarely be associated with arteriovenous (AV) fistulas. We present the first case involving a type IV dural AV fistula with a Chiari type I malformation. METHODS: Retrospective chart review was performed to obtain pertinent details regarding history and examination, pathologic findings, and treatment course. RESULTS: A 63-year-old woman with a 2-year history of migraines presented with 5 months of occipital, right-sided headaches and neck pain exacerbated by Valsalva maneuvers. Computed tomography (CT) and magnetic resonance imaging (MRI) of the head showed a possible right occipital AV malformation, bilateral cerebellar subdural hygromas, and tonsillar crowding at the foramen magnum indicating an acquired Chiari type I malformation. Angiography demonstrated a Cognardtype IV right posterior occipital dural AV fistula supplied by bilateral middle meningeal and posterior meningeal arteries. CONCLUSION: After treatment of the dural AV fistula, hygroma evacuation, and decompression of the acquired Chiari malformation, the patient's Valsalva-induced headaches abated.

An Integrated Management Paradigm for Skull Base Chordoma Based on Clinical and Molecular Characteristics.

Objective Previous work categorized skull base chordoma (SBC) into three genetic risk groups based on 1p36 and homozygous 9p21(p16) deletions, accounting for a wide variability in prognosis (A = low-risk, B = intermediate-risk, C = high-risk). However, it remains unclear how these groups could guide management. Study Design By integrating surgical outcome and adjuvant radiation (AdjXRT) information with genetic data on 152 tumors, we sought to develop an evidence-based management algorithm for SBC. Results Gross total resections (GTRs) were associated with improved progression free survival (PFS) in all genetic groups. For Group C tumors, GTR and AdjXRT independently contributed to PFS (multivariate Cox proportional hazard ratio [HR] = 0.14, p = 0.002, and HR = 0.40, p = 0.047, respectively). For Group B tumors, AdjXRT improved outcomes only when GTR was not feasible (log-rank p = 0.008), but not following GTR (log-rank p = 0.54). However, 24 of 25 Group A tumors underwent GTR, and AdjXRT for these did not confer any benefit (log-Rank p = 0.285). The high GTR rates in Group A could be explained by smaller tumor sizes (mean = 0.98cc/4.08cc/4.92cc for Group A/B/C, respectively, p = 0.031) and lack of invasiveness. Group A tumors were also more frequently diagnosed in young people ( p = 0.002) as asymptomatic lesions ( p = 0.001), suggesting that they could be precursors to tumors in higher risk groups. Conclusion Genotypic grouping by 1p36 and homozygous 9p21(p16) deletions can predict prognosis in SBC and guide management. GTR remains the cornerstone of SBC treatment and can be sufficient without AdjXRT in low and intermediate risk tumors. Low-risk tumors are associated with a less invasive phenotype, which makes them more amenable to GTR.

Applications of Endoscopic Endonasal Surgery in Early Childhood: A Case Series.

INTRODUCTION: Endoscopic endonasal surgery (EES) has been slower to gain popularity in early childhood due to anatomical challenges. We sought to describe the safety and efficacy of EES in early childhood. METHODS: All patients younger than 7 years who underwent EES at a large Cranial Base Center from 2002 to 2019 were reviewed as a retrospective cohort study. RESULTS: Thirty-six patients underwent EES before the age of 7 years. Four patients had two-stage EES. Two patients required combined transcranial and endonasal approaches. The mean age at the time of initial surgery was 4 years (range: 1-6). Twenty patients were male, and 16 were female. Of 21 tumors intended for resection, 11 patients had gross total resections, and 10 had near total (>95% tumor removed) resections. Nine patients (43%) had recurrences, of which 6 were craniopharyngiomas (p = 0.01). There was no difference in recurrence rates based on the degree of resection (p = 0.67). Three cerebrospinal fluid (CSF) leaks occurred following primary EES (8%). Following an increase in nasoseptal flap usage (31-52%) and CSF diversion (15-39%) in 2008, there was only one CSF leak out of 23 patients (4 vs. 15%; p = 0.54). Postoperatively, 1 patient developed a permanent new cranial neuropathy, and 1 patient developed a permanent visual field cut. Six patients developed permanent postoperative panhypopituitarism, of which all were craniopharyngiomas (p < 0.001). The mean follow-up was 64 months. CONCLUSIONS: Early childhood EES is both safe and technically feasible for a variety of pathologies.

Endoscopic Endonasal Resection of Cranio-Cervical Junction Chordoma and Ventral Chiari Decompression: A Case Report.

BACKGROUND: Chiari I malformations secondary to other causes represent a small subset of presenting symptomatic cases. Typically, the primary cause of the malformation is addressed first and results in resolution of the malformation and symptoms. However, in some cases, a patient may present with both a primary Chiari I malformation and another unrelated neurosurgical lesions. OBJECTIVE: To present a unique case in which resection of a ventral tumor allowed for spontaneous resolution of a simultaneously noted dorsal Chiari I malformation. METHODS: Pertinent data, including presenting symptoms, hospital course, surgical notes, preoperative images, and postoperative images, were collected using the electronic medical record. RESULTS: We present a case of a 46-yr-old man with a Chiari I malformation in conjunction with a ventral cranio-cervical junction chordoma. Endoscopic endonasal resection of the chordoma and ventral foramen magnum decompression resulted in radiographic resolution of the Chiari malformation and resolution of his symptoms. Our report represents a rare case of ventral foramen magnum decompression as a treatment for Chiari I malformation. CONCLUSION: It is felt that the chordoma mass effect was not the source of the Chiari I malformation. Thus, both ventral and dorsal decompressions of the posterior fossa may be considered for Chiari I decompression in select circumstances.

Neuroophthalmological manifestations of congenital aqueductal stenosis.

OBJECTIVE: Congenital aqueductal stenosis (CAS) is a common etiology of hydrocephalus that occurs in a subset of infants and may be linked to an increased incidence of ophthalmological abnormalities and delayed developmental milestones. Although hydrocephalus is common and widely studied, sparse literature exists on patients with isolated (no identifiable genetic link) CAS along with analysis of ophthalmological manifestations. In this study, the authors sought to describe the ophthalmological abnormalities and delayed developmental milestones of patients with isolated CAS. METHODS: Data of patients with CAS were prospectively entered and monitored in a surgical database maintained by the Department of Neurological Surgery at Children's Hospital of Pittsburgh from January 2005 to October 2016. Patients with a family history of congenital hydrocephalus, positive testing for genetic forms of aqueductal stenosis, other congenital abnormalities suggesting an underlying genetic syndrome, and stenosis/obstruction due to secondary causes were excluded from this study. Prenatal and perinatal history, CSF diversion history, and a variety of outcomes, including ophthalmological deficits and developmental milestones, were collected and analyzed. RESULTS: A total of 41 patients with isolated CAS were identified, with a mean follow-up duration of 6 years. Among that cohort, 26 patients (63.4%) developed neuroophthalmological complications, which were further stratified. Fourteen patients (34.1%) developed strabismus and 11 (26.8%) developed astigmatism, and 1 patient (2.4%) with papilledema was recorded. Among patients with ophthalmological abnormalities, 76.9% had delayed developmental milestones (p = 0.045). CONCLUSIONS: Patients with CAS were found to have increased risk of ophthalmological abnormalities requiring correction, along with an increased risk of delayed developmental milestones. Importantly, there was a significant correlation between the development of ophthalmological abnormalities and delayed developmental milestones that was independent of CSF diversion history. Larger patient cohort studies are required to explore whether earlier development of hydrocephalus, as is the case in CAS, causes elevated rates of neurological and ophthalmological complications, and if earlier CSF diversion correlates with improved outcomes.

Comparison of Follow-Up Length-Matched Single-Center Myelomeningocele Postnatal Closure Cohort to the Management of Myelomeningocele Study (MOMS) Trial Results.

OBJECTIVE: We sought to compare our large single-institution cohort of postnatal myelomeningocele closure to the 2 arms of the Management of Myelomeningocele Study (MOMS) trial at the designated trial time points, as well as assess outcomes at long-term follow-up among our postnatal cohort. METHODS: A single-institutional retrospective review of myelomeningocele cases presenting from 1995 to 2015 at Children's Hospital of Pittsburgh was performed. We compared outcomes at 12 and 30 months to both arms of the MOMS trial and compared our cohort's outcomes at those designated time points to our long-term outcomes. Univariate statistical analysis was performed as appropriate. RESULTS: One-hundred sixty-three patients were included in this study. All patients had at least 2-year follow-up, with a mean follow-up of 10 years (range 2-20 years). There was no difference in the overall distribution of anatomic level of defect. Compared to our cohort, the prenatal cohort had a higher rate of tethering at 12 months of age, 8 versus 1.8%. Conversely, the Chiari II decompression rate was higher in our cohort (10.4 vs. 1.0%). At 30 months, the prenatal cohort had a higher rate of independent ambulation, but our cohort demonstrated the highest rate of ambulation with or without assistive devices among the 3 groups. When comparing our cohort at these early time points to our long-term follow-up data, our cohort's ambulatory function decreased from 84 to 66%, and the rate of detethering surgery increased almost 10-fold. CONCLUSIONS: This study demonstrated that overall ambulation and anatomic-functional level were significantly better among our large postnatal cohort, as well as having significantly fewer complications to both fetus and mother, when compared to the postnatal cohort of the MOMS trial. Our finding that ambulatory ability declined significantly with age in this patient population is worrisome for the long-term outcomes of the MOMS cohorts, especially given the high rates of cord tethering at early ages within the prenatal cohort. These findings suggest that the perceived benefits of prenatal closure over postnatal closure may not be as substantial as presented in the original trial, with the durability of results still remaining a concern.

Shunt infection and malfunction in patients with myelomeningocele.

OBJECTIVE: Myelomeningocele (MMC) is frequently complicated by symptomatic hydrocephalus, necessitating early permanent CSF diversion and revision surgeries. Shunt infections are a common cause of shunt malfunction. This study aims to characterize long-term shunt-related outcomes of patients undergoing MMC closure. METHODS: A total of 170 patients undergoing MMC closure between the years of 1995 and 2017 were identified from a retrospective review of a prospectively populated surgical database at the Children's Hospital of Pittsburgh. Patients who underwent MMC closure and required ventriculoperitoneal (VP) shunt insertion met criteria and were included in the primary study analysis. Analysis with a Fisher exact test was performed for categorical variables, and Mann-Whitney U-tests were utilized for numerical data. RESULTS: Of the 158 total patients undergoing MMC closure and meeting inclusion criteria, 137 (87%) required VP shunt insertion. These 137 patients demonstrated a shunt revision rate of 21.1% per person-year and a shunt infection rate of 2.1% per person-year over a mean follow-up of 10.8 years. Patients had a mean of 3.4 ± 0.6 shunt surgeries prior to their first infection. Patients undergoing immediate shunt removal, external ventricular drain placement, or shunt replacement after clearing the infection had lower rates of subsequent infections than patients who initially were managed with shunt externalization (p < 0.001). Placement of a shunt at the time of MMC closure was not found to be a risk factor for infection. Of patients with initial shunt placement after the implementation of the Hydrocephalus Clinical Research Network protocol in 2011, the authors' institution has had a shunt infection rate of 4.2% per person-year and a revision rate of 35.7% per person-year. CONCLUSIONS: This study describes long-term outcomes of shunted MMC patients and factors associated with shunt infections. Most patients underwent multiple revisions prior to the first shunt infection. Shunt externalization may be ineffective at clearing the infection and should be avoided in favor of early shunt removal and external ventricular drainage, followed by shunt replacement once infection is demonstrated to have cleared.

Esthesioneuroblastoma with recurrent dural metastases: Long-term multimodality treatment and considerations.

BACKGROUND: Esthesioneuroblastoma (ENB) is a rare malignant disease and treatment protocols have not been standardized, varying widely by disease course and institutional practices. Management typically includes wide local excision through open or endoscopic resection, followed by radiotherapy, chemotherapy, and stereotactic radiosurgery. Tumor control can differ on a case-by-case basis. Herein, the complex management of a rare case of recurrent disease with multiple dural metastases is presented. CASE DESCRIPTION: A 60-year-old patient was diagnosed with ENB after presenting with anosmia and epistaxis. The patient underwent combined endonasal and transfrontal sinus craniofacial resection, followed by proton beam radiation therapy and chemotherapy. Subsequently, he developed a total of 25 dural metastases that were controlled with repeated Gamma Knife Radiosurgery (GKRS). In spite of post-treatment course that was complicated by radiation necrosis and local vasculopathy, the patient made significant recovery to functional baseline. CONCLUSION: The management of ENB entails multimodality and multidisciplinary care, which can help patients obtain disease control and long-term survival. Recurrent ENB dural metastases can behave as oligometastatic disease manageable with aggressive focal GKRS. As prognosis continues to improve, chronic treatment effects of radiation in such cases should be taken into consideration.

Early practices in endonasal skull base surgery during the COVID-19 pandemic: a global survey.

OBJECTIVE: During the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, endoscopic endonasal surgery (EES) is feared to be a high-risk procedure for the transmission of coronavirus disease 2019 (COVID-19). Nonetheless, data are lacking regarding the management of EES during the pandemic. The object of this study was to understand current worldwide practices pertaining to EES for skull base/pituitary tumors during the SARS-CoV-2 pandemic and provide a basis for the formulation of guidelines. METHODS: The authors conducted a web-based survey of skull base surgeons worldwide. Different practices by geographic region and COVID-19 prevalence were analyzed. RESULTS: One hundred thirty-five unique responses were collected. Regarding the use of personal protective equipment (PPE), North America reported using more powered air-purifying respirators (PAPRs), and Asia and Europe reported using more standard precautions. North America and Europe resorted more to reverse transcriptase-polymerase chain reaction (RT-PCR) for screening asymptomatic patients. High-prevalence countries showed a higher use of PAPRs. The medium-prevalence group reported lower RT-PCR testing for symptomatic cases, and the high-prevalence group used it significantly more in asymptomatic cases.Nineteen respondents reported transmission of COVID-19 to healthcare personnel during EES, with a higher rate of transmission among countries classified as having a medium prevalence of COVID-19. These specific respondents (medium prevalence) also reported a lower use of airborne PPE. In the cases of healthcare transmission, the patient was reportedly asymptomatic 32% of the time. CONCLUSIONS: This survey gives an overview of EES practices during the SARS-CoV-2 pandemic. Intensified preoperative screening, even in asymptomatic patients, RT-PCR for all symptomatic cases, and an increased use of airborne PPE is associated with decreased reports of COVID-19 transmission during EES.

Long-term outcomes in the treatment of pediatric skull base chordomas in the endoscopic endonasal era.

OBJECTIVE: Pediatric skull base chordoma is a rare entity that is traditionally considered to display aggressive behavior with an increased risk of recurrence. There is an absence of literature examining outcomes in the pediatric population in general and using the endoscopic endonasal approach (EEA). METHODS: The authors retrospectively reviewed all patients with skull base chordomas presenting by the age of 18 years to the Children's Hospital of Pittsburgh or the University of Pittsburgh Medical Center from 2004 to 2019. Clinical outcomes, the number and location of recurrences, and progression-free survival time were determined. RESULTS: Twenty patients met the study criteria. The most common presenting complaints were diplopia (n = 7), headache (n = 6), and swallowing difficulty (n = 4). Three cases were incidentally discovered. Twelve patients underwent single-stage EEA alone, 2 patients had two-stage EEA, and 6 patients had combined EEA with open far-lateral or extreme-lateral approaches. Fourteen patients underwent gross-total resection (GTR), and 6 patients had near-total resection. Larger tumors were more likely to require staging or a combined approach (86% vs 7%) and were less likely to receive GTR (33% vs 86%) but had comparable recurrence and mortality rates. Five patients developed CSF leaks requiring reoperation, 2 patients developed a permanent abducens nerve palsy, 1 patient suffered an internal carotid artery injury, 1 patient developed an epidural hematoma, and 1 patient developed a subdural empyema. Four (20%) patients had recurrence during follow-up (mean radiographic follow-up 59 months and mean time to local recurrence 19 months). Two patients with recurrence underwent further resection, and 1 patient elected to stop treatment. Both patients who underwent repeat resection experienced a second recurrence, one of whom elected to stop treatment. Both patients who died had an elevated Ki-67 (p = 0.039), one of whom developed de-differentiated histology. A third patient died of progressive spinal metastases without local recurrence and is one of 2 patients who developed postoperative spinal metastases. Both patients whose tumors became de-differentiated progressed from tumors with an initial Ki-67 of 15 or greater (p = 0.035) and received prior radiotherapy to the bulk tumor (p = 0.03). CONCLUSIONS: The majority of pediatric skull base chordomas, when managed at a specialized center with a goal of GTR, may have a better outcome than traditionally believed. Elevated Ki-67 rates may predict poor outcome and progression to de-differentiation.

Impact of a Hands-on Pre-Clinical Neurosurgery Elective Course on Second-Year Medical Student Interest and Attitudes.

INTRODUCTION: Medical student involvement opportunities and educational experiences with surgical residents during medical school have been shown to increase the chance of students deciding to specialize in surgical specialties. This study aims to determine the effect of a neurosurgery elective during the second preclinical year on student interest and opinion of neurosurgery. METHODS: Thirty-nine students completed opinion-based surveys and factual knowledge quizzes during a neurosurgical elective course over 3 iterations, which included lecture and skills lab instruction. Pre- and post-course surveys used the Likert scale, with a score of 1 corresponding to the most negative opinion and a score of 10 corresponding to the most positive opinion, in order to measure various aspects including interest in neurological surgery, understanding of the field, and perception of female inclusion in the field. Weekly pre- and post-lecture quizzes assessed practical knowledge of neurosurgical topics. RESULTS: A higher percentage of students rated neurosurgery highly as a career possibility (⩾8/10 interest level) post-course (58.6%) compared to pre-course (45.7%). Post-course, students reported a significantly increased mean understanding of neurosurgery on the Likert scale compared to pre-course (6.1 ± 1.7 vs 4.4 ± 2.0; P = .001). Knowledge based-content assessment revealed a significant increase in overall correct answers after lectures (meanpre = 3.85, meanpost = 5.05, P = .001). Inclusion of female instructors in the second and third iteration of the course resulted in a significant increase in students' perception of female inclusion in the field of neurosurgery (7.6 compared to 5.6, P = .01). CONCLUSIONS: Early exposure to subspecialties may assist in making important career decisions. The implementation of this neurosurgical elective improved medical students' perception of the field and enhanced knowledge of the lectures and procedures. This study can be used as a framework for implementation of this curriculum at other institutions.