Faculty Bibliography

BACKGROUND AND OBJECTIVES/OBJECTIVE:Normal pressure hydrocephalus (NPH) affects approximately 0.2% to 2.9% of adults older than 65 years and is characterized by progressive gait impairment, cognitive decline, and urinary incontinence. Cerebrospinal fluid shunting is the mainstay of treatment but carries a risk of overdrainage, leading to subdural collections. Evidence guiding the management of these collections in patients with shunted NPH remains limited. We aimed to characterize treatment strategies and outcomes for subdural collections in patients with shunted NPH and to propose a practical management framework for nonemergent presentations. METHODS:We performed a retrospective cohort study of patients with shunted NPH who developed subdural collections requiring treatment between January 2014 and September 2025. Interventions included valve pressure adjustment, middle meningeal artery (MMA) embolization, and surgical evacuation. Clinical, radiographic, and treatment data were extracted from the electronic health record. Time-to-resolution and recurrence were assessed using Kaplan-Meier analysis. Receiver operating characteristic analysis determined the predictive value of baseline collection volume for failure of valve adjustment. RESULTS:Sixty patients with 96 total collections underwent 91 valve pressure increases, 8 craniotomies for 8 collections, 23 MMA embolization procedures for 32 collections, and 15 subdural evacuating port system procedures for 16 collections. The median time to resolution for collections that underwent valve adjustment only, MMA embolization without evacuation, evacuation without MMA embolization, and both MMA embolization and evacuation was 1.91, 3.99, 1.77, and 5.17 months, respectively. Using pretreatment volume to predict valve adjustment failure demonstrated an area under the curve of 0.75 with an optimal cutoff of 40.05 cm3, corresponding to a sensitivity of 75.0% and a specificity of 71.4%. CONCLUSION/CONCLUSIONS:Baseline hematoma volume may help identify which shunted NPH patients with subdural hematomas are at higher risk of failing valve adjustment alone. We propose a volume-informed management framework in which larger hematomas (approximately >40 cm3) prompt earlier consideration of treatment escalation.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Cerebrospinal fluid shunting is a common treatment for hydrocephalus. Several techniques for ventricular catheter placement exist, yet comparative safety data remain limited. This study evaluated whether stereotactic navigation-assisted ventricular catheter placement is associated with reduced 30-day postoperative intracranial hemorrhage (ICH) rates. METHODS:This was a retrospective analysis of adults who underwent frontal or occipital shunt placement for hydrocephalus between 2014 and 2023. The primary exposure variable was the use of stereotactic navigation for ventricular catheter placement. The primary outcomes were hospital length of stay (LOS) and 30-day postoperative ICH. RESULTS:A total of 541 shunt placements were included (median age 72.5 years; 51.6% male). Normal pressure hydrocephalus represented the most common underlying diagnosis (60.3%). Stereotactic navigation was used in 221 cases (40.9%) and was more frequently employed in younger patients (66.0 vs 73.9 years; P < .001), more recent years (median 2021 vs 2019; P < .001), and cases involving non-normal pressure hydrocephalus diagnoses (P < .001). Overall, 12 patients (2.2%) developed ICH within 30 days of surgery. The 30-day ICH rate was significantly lower with stereotactic navigation (0.5% vs 3.4%; odds ratio 0.13, 95% CI 0.02-1.00; P = .033), corresponding to an absolute risk reduction of 2.99% and a number needed to treat of 34. Kaplan-Meier analysis demonstrated superior hemorrhage-free survival with navigation-assisted placement (log-rank P = .021), with most events occurring within the first 14 days postoperatively. Propensity-matched analysis demonstrated a similar effect size but fell short of statistical significance. Navigation use was not independently associated with LOS or any other complications. CONCLUSION/CONCLUSIONS:Stereotactic navigation-assisted ventricular catheter placement was associated with lower rates of 30-day postoperative ICH compared with non-navigation-assisted placement, with a number needed to treat of 34. Given the absence of adverse effects on LOS or overall complication rates, these findings support routine consideration of neuronavigation during shunt placement when available.

PURPOSE/OBJECTIVE:Pediatric low-grade gliomas (pLGGs) typically have excellent long-term outcomes; intratumoral hemorrhage is a rare, potentially dangerous complication. Hemorrhage risk in the context of molecular alterations and targeted therapies remains poorly characterized. We analyzed the incidence, timing, and independent risk factors for hemorrhage in a large contemporary pLGG cohort. METHODS:We conducted a retrospective cohort study of 236 children with pLGG treated at a single center (2011-2025). Clinical, radiographic, and molecular variables were abstracted. The primary endpoint was spontaneous tumoral hemorrhage. Time-to-event analyses utilized Kaplan-Meier methods and Cox proportional hazards modeling; penalized regression mitigated overfitting given the event rarity. RESULTS:Twelve patients (5.1%) experienced hemorrhage over 2,234 person-years (incidence: 0.54/100 person-years). Hemorrhage typically occurred years after initial tumor diagnosis (median 6.4 years). The presence of a KIAA1549::BRAF fusion in the tumor had the strongest association with hemorrhage, persisting across multivariable models (approximately sixfold increased risk), although estimates were limited by low event number. MAPK inhibitor exposure (specifically binimetinib and tovorafenib) was associated with hemorrhage in univariate analysis but partially confounded by fusion status. CSF diversion independently increased risk at brainstem, optic pathway, and hypothalamic locations. No hemorrhages occurred among patients with underlying genetic syndromes, including neurofibromatosis type 1 and tuberous sclerosis. CONCLUSION/CONCLUSIONS:Hemorrhage in pLGG is an infrequent late complication associated with tumor biology. KIAA1549::BRAF fusion may identify a higher-risk subgroup, with MAPK inhibitor exposure and CSF diversion further modifying risk. These findings support biology-informed surveillance and personalized management strategies for at-risk children.

PURPOSE/OBJECTIVE:Prospective, multi-institutional surgical data collection in pediatric neuro-oncology remains limited despite substantial variation in operative and perioperative management across institutions. To address this, we are developing the NeuroPoint Alliance (NPA) Quality Outcomes Database (QOD) Pediatric Tumor Surgery Registry. Here, we used a modified Delphi process to define a core outcome set for the registry. METHODS:A modified Delphi study was conducted among pediatric neurosurgeons serving as site principal investigators for the proposed registry. Candidate data elements were rated on a 9-point Likert scale. Consensus for inclusion was predefined as ≥70% of respondents rating an item 7-9 and ≤15% rating it 1-3; consensus for exclusion was defined as the reverse. Items not reaching consensus in Round 1, along with new items derived from free-text responses, were re-evaluated in Round 2. Near-consensus items after Round 2 underwent discussion and re-rating in a final virtual round. RESULTS:In Round 1, 48 of 83 candidate items (57.8%) reached consensus for inclusion, while 35 advanced to Round 2. Fourteen additional candidate items were generated from free-text suggestions, resulting in 49 items evaluated in Round 2; 13 reached consensus for inclusion. Seventeen items were classified as near-consensus and advanced to the final round, in which 4 reached consensus for inclusion and 1 for exclusion. Across all three rounds, 66 items achieved consensus. CONCLUSIONS:This modified Delphi study established a consensus-based core outcome set for the NPA QOD Pediatric Tumor Surgery Registry, providing a practical foundation for standardized, prospective, multicenter pediatric neurosurgical oncology data collection.

BACKGROUND:Glioblastoma intramedullary spinal cord metastasis (GISCM) is a rare sequela of high-grade astrocytoma and glioblastoma multiforme (GBM). Discrete intramedullary spinal cord metastases are less common than spinal leptomeningeal spread and may follow a more indolent course. Once identified as GISCM, palliative maximal safe resection of the tumor may be considered to alleviate neurological symptoms. Reports describing the surgical management of these rare lesions, including the use of emerging technologies that may aid in maximal safe resection, are sparse. A further understanding is also required regarding the course of disease and factors contributing to mortality in GISCM. METHODS:We reviewed the intraoperative management and clinical course of three patients treated for GISCM at our institution between 2015 and 2024. We additionally conducted a PRISMA-guided systematic literature review of PubMed Central, MEDLINE, and Bookshelf databases through May 26th, 2025, including original patient reports of GISCM from cranial astrocytoma or GBM. The disease course, management strategies, and causes of mortality in previously reported cases were analyzed. RESULTS:Our institutional cohort had a mean time to spinal metastasis of 26.2 months from diagnosis of cranial disease (range 17.5-40.5 months), with a mean survival of 9.2 months following maximal safe resection of extramedullary components (range 7-12 months). In two cases, intraoperative Stimulated Raman Histology (SRH) was employed to facilitate the rapid identification of metastatic GBM, thereby influencing surgical strategy. In one case, 5-aminolevulinic acid (5-ALA) was used to differentiate between tumor and spinal cord parenchyma, facilitating maximal safe debulking without neurological injury. Literature review identified 38 prior reported cases of GISCM, with a median time to spinal diagnosis of 11.0 months and a median survival of 3.5 months thereafter. The cause of death in the review cohort often involved multiple factors, and when analyzed for contributing factors to death, 38.7% involved cranial progression, 38.7% involved progression of spinal disease, and 29.0% involved medical complications. Gait ataxia at presentation was associated with shorter survival in review patients, potentially reflecting advanced disease with extramedullary cord compression. CONCLUSION/CONCLUSIONS:GISCM represents an entity distinct from leptomeningeal disease and may be managed in conjunction with recurrent cranial disease. Surgical debulking is a technically feasible strategy that can be safely facilitated using tools employed in the management of intracranial GBM, facilitating maximal safe resection without compromising survival.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Normal pressure hydrocephalus (NPH) is characterized by the classic triad of cognitive decline, gait instability, and urinary incontinence in the setting of ventriculomegaly with normal intracranial pressure. Cerebrospinal fluid diversion is the current standard treatment, yet it carries a risk of overdrainage, resulting in subdural hematoma or hygroma. Different valves have been developed to mitigate this risk, yet consensus remains unclear regarding optimal valve for NPH. METHODS:We performed a retrospective cohort study on all patients with NPH who underwent cerebrospinal fluid shunting or revision between January 2014 and September 2025 at our institution. Demographic, clinical, and radiological data were collected from the electronic health record. Kaplan-Meier survival analysis, univariate logistic regression, and multivariate modeling were used to identify predictors of subdural collections and the need for surgical treatment. RESULTS:Since our change in practice from the Integra NPH Low Flow Valve (Low Flow OSV) to other valves in 2022, we observed a rise in symptomatic subdural collections. Programmable valves were associated with a markedly increased 1-year risk of both subdural collection formation and need for surgical intervention compared with the Low Flow OSV. Overall, Certas and Strata valves demonstrated higher rates of subdural collections requiring surgery than the Low Flow OSV (14.6% vs 2.1%, P < .001; 10.5% vs 2.1%, P = .005, respectively). On multivariate analysis, both the Strata and Certas valves were independently associated with increased odds of developing any subdural collection and necessitating surgery. Vascular disease and dual antiplatelet therapy also increased risk. CONCLUSION/CONCLUSIONS:In this large single-center cohort study, programmable valves, specifically the Certas and Strata, were associated with an increased rate and severity of subdural collections compared with the Low Flow OSV. The use of low-flow designs may mitigate complications for the NPH population, and the use of lower programmable valve settings should be carefully considered.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Red blood cell transfusions are commonly required in pediatric cranial vault remodeling (CVR); however, they carry risks and potential complications. This study evaluates the evidence on perioperative blood conservation agents assessing their efficacy in optimizing and reducing transfusion requirements in CVR. METHODS:A systematic review was conducted using PubMed/MEDLINE, Scopus, Embase, Web of Sciences, and Google Scholar according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to assess articles discussing blood conservation agents in pediatric CVR. A network meta-analysis compared the effectiveness of different agents including tranexamic acid (TXA), aminocaproic acid (ACA), aprotinin, erythropoietin (EPO), and iron. RESULTS:Sixteen studies analyzing 1072 patients with a mean age of 15.6 months and weight of 8.78 kg were included. The most reported craniosynostosis subtypes were sagittal (30.2%) and metopic (13.8%). TXA and ACA were independently associated with lower transfusion rates and volumes compared with placebo (ACA: odds ratio [OR], 0.25; 95% CI, 0.08-0.80; TXA: OR, 0.17; 95% CI, 0.07-0.42). Combination therapy with TXA + EPO + iron (OR: 0.004, 95% CI: 0.002-0.10) or ACA + EPO (OR: 0.04, 95% CI: 0.01-0.32) were associated with reductions in transfusion rates. Network meta-analysis ranking revealed TXA + EPO + iron (Surface Under the Cumulative Ranking [SUCRA]: 98.90%) and ACA + EPO (SUCRA: 75.41%) as the most effective treatments for reducing transfusion rates. While TXA was associated with significant reductions in blood loss compared with placebo (standard mean difference: -1.26, 95% CI: -1.97 to -0.56), ACA ranked highest for blood loss reduction (ACA: SUCRA, 84.58% vs TXA: SUCRA, 72.43%). Combination of TXA + EPO + iron was associated with significantly reduced hospital length of stay (standard mean difference: -1.00, 95% CI: -1.71 to -0.29). No treatment significantly affected the duration of surgery, and there were no reported treatment-associated thromboembolic events. CONCLUSION/CONCLUSIONS:Our meta-analysis reveals that TXA + ACA reduce red blood cell transfusion rates and volumes, with TXA + EPO + iron and ACA + EPO being most effective. This highlights the superiority of combination therapies and underscores the need for structured multimodal protocols in perioperative blood conservation for pediatric CVR.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Adult biomechanical studies suggest a significant reduction in flexion-extension motion after occipitocervical and atlantoaxial fusion. Anecdotal experience in children suggests a lower magnitude of reduction in motion after these procedures, but high-quality quantitative assessments of this motion have not yet been performed. As such, the aim of this study was to determine the magnitude of reduction in cervical spine flexion-extension after O-C2 and C1-2 fusion in pediatric patients. METHODS:The Pediatric Spine Study Group international registry was queried for patients aged 21 years or younger who underwent O-C2 or C1-2 instrumentation and fusion. Patients with cervical spine flexion-extension radiographs preoperatively and ≥6 months postoperatively were included. Flexion, extension, and overall range of motion (ROM) of the cervical spine were measured on radiographs using McGregor line and the inferior endplate of C7. RESULTS:In total, 34 patients were included, with 19 undergoing index O-C2 and 15 undergoing index C1-2 stabilization. The mean age was 9.3 ± 4.5 years with average follow-up of 3.5 ± 2.6 years. The most common etiologies were syndromic (n = 20) and congenital (n = 9). Patients undergoing O-C2 fusion had reduced neck extension (80° vs 69.6°, P = .003) and overall ROM (92.9° vs 80°, P = .002) after stabilization, but no significant reduction in flexion (-12.9° vs -10.4°, P = .324). After C1-2 fusion, there was no significant reduction in overall ROM (85.0° vs 77.5°, P = .079), extension (70.5° vs 63.4°, P = .120), or flexion (-14.6° vs -14.0°, P = .831). CONCLUSION/CONCLUSIONS:In this cohort, children undergoing O-C2 stabilization had a 13.9% reduction in flexion-extension motion of the cervical spine, primarily due to a reduction in extension. There may be a smaller reduction in flexion-extension motion after stabilization in children when compared with adult studies. Further studies with video analysis including axial rotation and lateral bending will be necessary to comprehensively quantify cervical spine motion after fusion across the occipitocervical and atlantoaxial junctions.

PURPOSE/OBJECTIVE:To identify clinical variables associated with ventricular shunt infection and shunt failure in pediatric hydrocephalus. METHODS:Patients ≤ 18 years treated with ventricular shunts between 2013 and 2024 were identified from one institution's electronic medical record. Children with a confirmed diagnosis of hydrocephalus and ≥ 6 months of postoperative follow-up were included. Primary and revision shunt surgeries were included. Records were manually reviewed for clinical variables. Statistical analyses were performed using R (version 4.2.3). RESULTS:The dataset included 474 surgeries, 146 primary and 328 revisions, undergone by 226 patients. Infection necessitating removal of a previously placed shunt occurred following 3.59% (17/474) of cases. Discharge in ≤ 4 days had a 75% lower relative risk for infection compared to stays > 4 days (1.5% vs. 6% 100-day infection risk; p = 0.011). Patients who underwent revision surgeries for shunt infections were more likely to experience subsequent infections in the first 100 days postoperatively than those revised for other causes (2.42% vs. 21.05%; p < 0.0001). Patient characteristics associated with shunt failure during the 10-year study included younger age (median age: 2.23 years in those with failure vs. 6.62 years in those without; p < 0.0002) and lower weight (median weight: 11.8 kg vs. 20.3 kg; p < 0.0002) at the time of admission. Congenital hydrocephalus (OR = 1.86; p = 0.0045) and aqueductal stenosis (OR = 1.75; p = 0.025) were also associated with shunt failure. CONCLUSIONS:Length of stay > 4 days and previous shunt infection are associated with an increased risk of infection after shunt surgery. These findings are important to consider when counseling pediatric patients and during postoperative monitoring.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Hydrocephalus after Gamma Knife® stereotactic radiosurgery (SRS) for vestibular schwannomas is a rare but manageable occurrence. Most series report post-SRS communicating hydrocephalus in about 1% of patients, thought to be related to a release of proteinaceous substances into the cerebrospinal fluid. While larger tumor size and older patient age have been associated with post-SRS hydrocephalus, the influence of baseline ventricular anatomy on hydrocephalus risk remains poorly defined. METHODS:A single-institution retrospective cohort study examining patients who developed symptomatic communicating hydrocephalus after undergoing Gamma Knife® SRS for unilateral vestibular schwannomas from 2011 to 2021 was performed. Patients with prior hydrocephalus and cerebrospinal fluid diversion or prior surgical resection were excluded. Baseline tumor volume, third ventricle width, and Evans Index (EI)-maximum width of the frontal horns of the lateral ventricles/maximum internal diameter of the skull-were measured on axial postcontrast T1-weighted magnetic resonance imaging. RESULTS:A total of 378 patients met the inclusion criteria; 14 patients (3.7%) developed symptomatic communicating hydrocephalus and 10 patients (2.6%) underwent shunt placement and 4 patients (1.1%) were observed with milder symptoms. The median age of patients who developed hydrocephalus was 69 years (IQR, 67-72) and for patients younger than age 65 years, the risk was 1%. For tumor volumes <1 cm3, the risk of requiring shunting was 1.2%. The odds of developing symptomatic hydrocephalus were 5.0 and 7.7 times higher in association with a baseline EI > 0.28 (P = .024) and tumor volume >3 cm3 (P = .007), respectively, in multivariate analysis. Fourth ventricle distortion on pre-SRS imaging was significantly associated with hydrocephalus incidence (P < .001). CONCLUSION/CONCLUSIONS:Patients with vestibular schwannoma with higher baseline EI, larger tumor volumes, and fourth ventricle deformation are at increased odds of developing post-SRS hydrocephalus. These patients should be counseled regarding risk of hydrocephalus and carefully monitored after SRS.