Surgical management of Rathke cleft cysts in pediatric patients: a single institution experience

OBJECTIVE

Rathke cleft cysts (RCCs) are benign, epithelial-lined sellar lesions that arise from remnants of the craniopharyngeal duct. Due to their rarity in the pediatric population, data are limited regarding the natural history and optimal management of growing or symptomatic RCCs. We present our institutional experience with the surgical management of RCCs.

METHODS

We performed a retrospective study of consecutive RCC patients ≤ 18 years old treated surgically at our institution between 2006 and 2022.

RESULTS

Overall, 567 patients with a diagnosis of pituitary mass or cyst were identified. Of these, 31 had a histopathological diagnosis of RCC, 58% female and 42% male. The mean age was 13.2 ± 4.2 years. Presenting symptoms included headache (58%), visual changes (32%), and endocrinopathies or growth delay (26%); 13% were identified incidentally and subsequently demonstrated growth on serial imaging. Six percent presented with symptomatic intralesional hemorrhage. Surgical approach was transsphenoidal for 90% of patients and orbitozygomatic for 10%. Preoperative headaches resolved in 61% of patients and preoperative visual deficits improvement in 55% after surgery. New pituitary axis deficits were seen in 9.7% of patients. Only two complications occurred from a first-time surgery: one cerebrospinal fluid leak requiring lumbar drain placement, and one case of epistaxis requiring cauterization. No patients experienced new visual or neurological deficits. Patients were followed postoperatively with serial imaging at a mean follow-up was 62.9 ± 58.4 months. Recurrence requiring reoperation occurred in 32% of patients. Five-year progression-free survival was 47.9%. Except for one patient with multiple neurological deficits from a concurrent tectal glioma, all patients had a modified Rankin Scale score of 0 or 1 (good outcome) at last follow-up.

CONCLUSION

Due to their secretory epithelium, pediatric RCCs may demonstrate rapid growth and can cause symptoms due to local mass effect. Surgical management of symptomatic or growing pediatric RCCs via cyst fenestration or partial resection of the cyst wall can be performed safely, with good neurologic outcomes. There is a nontrivial risk of endocrinologic injury, and long-term follow up is needed due to high recurrence rates.

Treatment of pediatric intracranial aneurysms: institutional case series and systematic literature review

INTRODUCTION

Pediatric intracranial aneurysms (IAs) are rare and have distinct clinical profiles compared to adult IAs. They differ in location, size, morphology, presentation, and treatment strategies. We present our experience with pediatric IAs over an 18-year period using surgical and endovascular treatments and review the literature to identify commonalities in epidemiology, treatment, and outcomes.

METHODS

We identified all patients < 20 years old who underwent treatment for IAs at our institution between 2005 and 2020. Medical records and imaging were examined for demographic, clinical, and operative data. A systematic review was performed to identify studies reporting primary outcomes of surgical and endovascular treatment of pediatric IAs. Demographic information, aneurysm characteristics, treatment strategies, and outcomes were collected.

RESULTS

Thirty-three patients underwent treatment for 37 aneurysms over 18 years. The mean age was 11.4 years, ranging from one month to 19 years. There were 21 males (63.6%) and 12 females (36.4%), yielding a male: female ratio of 1.75:1. Twenty-six (70.3%) aneurysms arose from the anterior circulation and 11 (29.7%) arose from the posterior circulation. Aneurysmal rupture occurred in 19 (57.5%) patients, of which 8 (24.2%) were categorized as Hunt-Hess grades IV or V. Aneurysm recurrence or rerupture occurred in five (15.2%) patients, and 5 patients (15.2%) died due to sequelae of their aneurysms. Twenty-one patients (63.6%) had a good outcome (modified Rankin Scale score 0-2) on last follow up. The systematic literature review yielded 48 studies which included 1,482 total aneurysms (611 with endovascular treatment; 656 treated surgically; 215 treated conservatively). Mean aneurysm recurrence rates in the literature were 12.7% and 3.9% for endovascular and surgical treatment, respectively.

CONCLUSIONS

Our study provides data on the natural history and longitudinal outcomes for children treated for IAs at a single institution, in addition to our treatment strategies for various aneurysmal morphologies. Despite the high proportion of patients presenting with rupture, good functional outcomes can be achieved for most patients.

Special Considerations in Pediatric Endoscopic Skull Base Surgery

Originally pioneered in adults, endoscopic endonasal approaches for skull base pathology are being increasingly applied as a minimally invasive alternative for young children. Intrinsic anatomic differences between these patient populations have sparked discussions on the feasibility, safety, and efficacy of these techniques in pediatric patients. This work aims to serve as a primer for clinicians engaged in the rapidly evolving field of pediatric endoscopic skull base surgery. A succinct overview of relevant embryology, sinonasal anatomy, and diagnostic workup is presented to emphasize key differences and unique technical considerations. Additional discussions regarding select skull base lesions, reconstructive paradigms, potential surgical complications, and postoperative care are also highlighted in the setting of multidisciplinary teams.

Numerical flow experiment for assessing predictors for cerebrovascular accidents in patients with PHACES syndrome

There is an increased risk of cerebrovascular accidents (CVA) in individuals with PHACES, yet the precise causes are not well understood. In this analysis, we aimed to examine the role of arteriopathy in PHACES syndrome as a potential contributor to CVA. We analyzed clinical and radiological data from 282 patients with suspected PHACES syndrome. We analyzed clinical features, including the presence of infantile hemangioma and radiological features based on magnetic resonance angiography or computed tomography angiography, in individuals with PHACES syndrome according to the Garzon criteria. To analyze intravascular blood flow, we conducted a simulation based on the Fluid-Structure Interaction (FSI) method, utilizing radiological data. The collected data underwent statistical analysis. Twenty patients with PHACES syndrome were included. CVAs were noted in 6 cases. Hypoplasia (p = 0.03), severe tortuosity (p < 0.01), absence of at least one main cerebral artery (p < 0.01), and presence of persistent arteries (p = 0.01) were associated with CVAs, with severe tortuosity being the strongest predictor. The in-silico analysis showed that the combination of hypoplasia and severe tortuosity resulted in a strongly thrombogenic environment. Severe tortuosity, combined with hypoplasia, is sufficient to create a hemodynamic environment conducive to thrombus formation and should be considered high-risk for cerebrovascular accidents (CVAs) in PHACES patients.

Intra-tumoral T cells in pediatric brain tumors display clonal expansion and effector properties

Brain tumors in children are a devastating disease in a high proportion of patients. Owing to inconsistent results in clinical trials in unstratified patients, the role of immunotherapy remains unclear. We performed an in-depth survey of the single-cell transcriptomes and clonal relationship of intra-tumoral T cells from children with brain tumors. Our results demonstrate that a large fraction of T cells in the tumor tissue are clonally expanded with the potential to recognize tumor antigens. Such clonally expanded T cells display enrichment of transcripts linked to effector function, tissue residency, immune checkpoints and signatures of neoantigen-specific T cells and immunotherapy response. We identify neoantigens in pediatric brain tumors and show that neoantigen-specific T cell gene signatures are linked to better survival outcomes. Notably, among the patients in our cohort, we observe substantial heterogeneity in the degree of clonal expansion and magnitude of T cell response. Our findings suggest that characterization of intra-tumoral T cell responses may enable selection of patients for immunotherapy, an approach that requires prospective validation in clinical trials.

Circular extrachromosomal DNA promotes tumor heterogeneity in high-risk medulloblastoma

Circular extrachromosomal DNA (ecDNA) in patient tumors is an important driver of oncogenic gene expression, evolution of drug resistance and poor patient outcomes. Applying computational methods for the detection and reconstruction of ecDNA across a retrospective cohort of 481 medulloblastoma tumors from 465 patients, we identify circular ecDNA in 82 patients (18%). Patients with ecDNA-positive medulloblastoma were more than twice as likely to relapse and three times as likely to die within 5 years of diagnosis. A subset of tumors harbored multiple ecDNA lineages, each containing distinct amplified oncogenes. Multimodal sequencing, imaging and CRISPR inhibition experiments in medulloblastoma models reveal intratumoral heterogeneity of ecDNA copy number per cell and frequent putative 'enhancer rewiring' events on ecDNA. This study reveals the frequency and diversity of ecDNA in medulloblastoma, stratified into molecular subgroups, and suggests copy number heterogeneity and enhancer rewiring as oncogenic features of ecDNA.

Artificial cranial deformation in Tiwanaku, Bolivia

PURPOSE

Herein lies a brief historical review of the practice of artificial cranial deformation (ACD) in Tiwanaku, Bolivia, a pre-Columbian archeological ruin once regarded as one of the most powerful pre-Inca regions whose influence extended into present-day Peru and Chile from 600 to 1000 AD. We describe the history, purpose, and implications of ACD from both a neuroanatomical and cultural perspective.

METHODS

A literature review was conducted through PubMed on the history of artificial cranial deformation in South America, concentrating on the Tiwanaku region. The authors searched all available data with no specific time reference, using the mentioned keywords: ACD, neuroanatomical implications of ACD, cultural and social functions of ACD, Tiwanaku society, and Andean civilization.

RESULTS

Early Andean civilization was hierarchical and stratified. In Tiwanaku, the practice of ACD served to delineate one's social class, caste, lineage, and vocation. This was especially useful for warriors, who distinguished their fellow combatants from insurgents by differences in their cranial structure. ACD was usually conducted within the first few months of an infant's life before morphogenetic features became permanent. Two popular cranial styles-tabular and annular-were achieved by applying various mechanical apparatus and resulted in several cranial shapes (conical, box-like, flattened, etc.). Neuroanatomically, each deformation technique and the duration for which mechanical stress was applied influenced the solidification of cranial bones and shaped the frontal, occipital, parietal, and temporal bones differently. Cognitive deficits and plagiocephalic defects were recorded in limitation and may have been overlooked as the era's occupational demands were more labor-intensive than knowledge-driven.

CONCLUSION

In Tiwanaku, the custom of ACD was used to demonstrate group identity, with alterations of the cranial shape corresponding to a particular headdress. ACD was used to distinguish an individual's social identity, separating different groups of society into castes, classes, and slaves (Brain, 1979). The custom has also been used to mark territory and emphasize ethnic differences among groups, with potential cognitive implications that were largely unrecorded.

Anticoagulation for the treatment of septic cerebral venous sinus thrombosis in the setting of pediatric sinogenic and otogenic intracranial infections

OBJECTIVE

Septic cerebral venous sinus thrombosis (CVST) is a recognized complication of pediatric sinogenic and otogenic intracranial infections. The optimal treatment paradigm remains controversial. Proponents of anticoagulation highlight its role in preventing thrombus propagation and promoting recanalization, while others cite the risk of hemorrhagic complications, especially after a neurosurgical procedure for an epidural abscess or subdural empyema. Here, the authors investigated the diagnosis, management, and outcomes of pediatric patients with sinogenic or otogenic intracranial infections and a septic CVST.

METHODS

All patients 21 years of age or younger, who presented with an intracranial infection in the setting of sinusitis or otitis media and who underwent neurosurgical treatment at Connecticut Children's, Rady Children's Hospital-San Diego, or Ann and Robert H. Lurie Children's Hospital of Chicago from March 2015 to March 2023, were retrospectively reviewed. Demographic, clinical, and radiological data were systematically collated.

RESULTS

Ninety-six patients were treated for sinusitis-related and/or otitis media-related intracranial infections during the study period, 15 (15.6%) of whom were diagnosed with a CVST. Of the 60 patients who presented prior to the COVID-19 pandemic, 6 (10.0%) were diagnosed with a septic CVST, whereas of the 36 who presented during the COVID-19 pandemic, 9 (25.0%) had a septic CVST (p = 0.050). The superior sagittal sinus was involved in 12 (80.0%) patients and the transverse and/or sigmoid sinuses in 4 (26.7%). Only 1 (6.7%) patient had a fully occlusive thrombus. Of the 15 patients with a septic CVST, 11 (73.3%) were initiated on anticoagulation at a median interval of 4 (IQR 3-5) days from the most recent neurosurgical procedure. Five (45.5%) patients who underwent anticoagulation demonstrated complete recanalization on follow-up imaging, and 4 (36.4%) had partial recanalization. Three (75.0%) patients who did not undergo anticoagulation demonstrated complete recanalization, and 1 (25.0%) had partial recanalization. None of the patients treated with anticoagulation experienced hemorrhagic complications.

CONCLUSIONS

Septic CVST is frequently identified among pediatric patients undergoing neurosurgical intervention for sinogenic and/or otogenic intracranial infections and may have become more prevalent during the COVID-19 pandemic. Anticoagulation can be used safely in the acute postoperative period if administered cautiously, in a monitored setting, and with interval cross-sectional imaging. However, some patients exhibit excellent outcomes without anticoagulation, and further studies are needed to identify those who may benefit the most from anticoagulation.

Human microglia maturation is underpinned by specific gene regulatory networks

Microglia phenotypes are highly regulated by the brain environment, but the transcriptional networks that specify the maturation of human microglia are poorly understood. Here, we characterized stage-specific transcriptomes and epigenetic landscapes of fetal and postnatal human microglia and acquired corresponding data in induced pluripotent stem cell (iPSC)-derived microglia, in cerebral organoids, and following engraftment into humanized mice. Parallel development of computational approaches that considered transcription factor (TF) co-occurrence and enhancer activity allowed prediction of shared and state-specific gene regulatory networks associated with fetal and postnatal microglia. Additionally, many features of the human fetal-to-postnatal transition were recapitulated in a time-dependent manner following the engraftment of iPSC cells into humanized mice. These data and accompanying computational approaches will facilitate further efforts to elucidate mechanisms by which human microglia acquire stage- and disease-specific phenotypes.

Atypical Molecular Features of Pediatric Tectal Glioma: A Single Institutional Series

We present 4 children (diagnosed between 1 and 8 y, 3 females and 1 male) with molecularly distinct tectal gliomas (2 KRAS mutant, 1 EGFR mutant, 1 SRGAP3-RAF-1 fusion) that contributes to the growing literature of this uncommonly biopsied tumor. The patient with EGFR R222C mutation had a more severe course, earlier diagnosis, subsequent leptomeningeal metastatic disease, required more aggressive therapies, and died 9 years after diagnosis. Patients with KRAS mutations and SRGAP3-RAF-1 fusion had a more indolent course. Our series expands the molecular phenotype of tectal glioma with the potential for leptomeningeal dissemination. Future studies on establishing genotypic/phenotypic correlation from those who undergo biopsy are needed.

Using a Hybrid Approach to Increase the Impact of Medical Response to Natural Disasters

The United Nations (UN) established an umbrella of organizations to manage distinct clusters of humanitarian aid. The World Health Organization (WHO) oversees the health cluster, giving it responsibility for global, national, and local medical responses to natural disasters. However, this centralized structure insufficiently engages local players, impeding robust local implementation. The Gorkha earthquake struck Nepal on April 25, 2015, becoming Nepal's most severe natural disaster since the 1934 Nepal-Bihar earthquake. In coordinated response, 2 organizations, Empower Nepali Girls and International Neurosurgical Children's Association, used a hybrid approach integrating continuous communication with local recipients. Each organization mobilized its principal resource strengths-material medical supplies or human capital-thereby efficiently deploying resources to maximize the impact of the medical response. In addition to efficient resource use, this approach facilitates dynamic medical responses from highly mobile organizations. Importantly, in addition to future earthquakes in Nepal, this medical response strategy is easily scalable to other natural disaster contexts and other medical relief organizations. Preemptively identifying partner organizations with complementary strengths, continuous engagement with recipient populations, and creating disaster- and region-specific response teams may represent viable variations of the WHO cluster model with greater efficacy in local implementation of treatment in acute disaster scenarios.

Novel use of nonpenetrating titanium clips for pediatric primary spinal dural closure: A technical note

BACKGROUND

Dural closure is an important part of any pediatric spinal procedure with intradural pathology to prevent post-operative cerebrospinal fluid (CSF) egress and associated complications. Utilization of nonpenetrating titanium clips is one closure option that may have technical advantages such as ease of use and amenability to a narrow surgical corridor. No data exist on the efficacy of these clips for pediatric spinal dural closure.

METHODS

A single surgeon case series of 152 pediatric patients underwent procedures involving lumbar durotomy with subsequent dural closure using the AnastoClip® nonpenetrating titanium clip closure system. Rates of infection and cerebrospinal fluid leak were measured during the follow-up period.

RESULTS

A total of 152 pediatric patients (mean age: 6.25 ± 5.85 years, 50.7 % female) underwent intradural surgery with clip closure. The mean follow-up time was 57.0 ± 28.5 months. All patients were initially indicated for procedures involving spinal durotomy, with a majority being isolated tethered cord release (84.2 %). Others required tethered cord release and excision of a lipomyelomeningocele, spinal meningioma or arachnoid cyst (15.8 %). Post operative CSF leak occurred in two (1.32 %) patients at 11 and 18 days. Only one (0.66 %) patient was diagnosed with an infection, which was in a separate patient from those that had CSF leaks.

CONCLUSION

The remarkably low incidence of post-operative CSF leak and infection with nonpenetrating titanium clips suggests a strong safety and efficacy profile for this form of dural closure in a pediatric cohort. Further research evaluating this technique is required to fully demonstrate its acceptability as a cost-effective alternative to traditional suture-based closure.

Prognostic factors in diffuse leptomeningeal glioneuronal tumor (DLGNT): a systematic review

BACKGROUND

Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare tumor, first described by the WHO Classification of Central Nervous System Tumors in 2016. The clinical course is variable. Most tumors have low-grade histological findings although some may have more aggressive features. The goal of this systematic review was to identify prognostic factors for poor overall survival (OS).

MATERIAL AND METHODS

We performed a systematic review using three databases (PubMed, Google Scholar, and Embase) and the following search terms: diffuse leptomeningeal glioneuronal tumor, DLGNT, DLMGNT. Statistical analysis was performed using Statistica 13.3.

RESULTS

We included 34 reports in our review comprising 63 patients, published from 2016 to 2022. The median OS was 19 months (range: 12-51 months). Using multivariable Cox survival analysis, we showed that Ki-67 ≥ 7%, age > 9 years, symptoms of elevated intracranial pressure (ICP) at admission, and the presence of contrast-enhancing intraparenchymal tumor are associated with poor OS. Receiver operating characteristic (ROC) analysis identified Ki-67 ≥ 7% as a significant predictor of poor OS.

CONCLUSIONS

Signs or symptoms of increased ICP with imaging findings of diffuse leptomeningeal enhancement should raise suspicion for DLGNT. In our systematic review, Ki-67 ≥ 7% was the most important prognostic factor for OS in DLGNT. The presence of intraparenchymal tumor with contrast enhancement was thought to represent disease progression and, together with patient age, was associated with poor OS.

The role of methylation profiling in histologically diagnosed neurocytoma: a case series

Purpose

To highlight the clinical, neuroradiographic, neuropathologic, and molecular features of histologically identified neurocytoma in a pediatric cohort and highlight the evolving use methylation profiling in providing diagnostic clarity in difficult to diagnosis pediatric brain tumors.

Methods

Five consecutive children (ages 9–13, 2 girls 3 boys) were histologically diagnosed with neurocytoma at Rady Children’s Hospital San Diego from 2012 to 2018. Clinical and molecular features were analyzed with regards to treatment course and outcome.

Results

Presenting symptoms included seizures (n = 2), syncope (n = 1), headache (n = 2), visual disturbances (n = 2) and emesis (n = 2). Tumor location included intraventricular (n = 2), intraventricular with parenchymal spread (n = 1), and extraventricular (n = 2). Magnetic resonance imaging demonstrated reduced diffusivity (2/5), signal abnormality on susceptibility-weighted sequences (3/5), and varying degrees of contrast enhancement (4/5). All patients underwent surgical resection alone. Recurrence occurred in four children that were treated with surgery (4/4), adjuvant radiation (2/4), and chemoradiation (1/4). Neuropathologic features included positivity for GFAP (4/5), synaptophysin (4/5), NSE (2/2), NeuN (4/4), and variable Ki-67 (< 1% to 15%). Next generation sequencing (3/5) and microarray (3/5) collectively were abnormal in four of five tumors. Methylation profiling was successfully performed on four of five samples which led to modification of diagnosis in two patients and the others were either unclassifiable or confirmatory with the histologic diagnosis. Mean time to follow up was 77 months (range 44–112 months). Mean progression free survival and overall survival were 24 months (range 6 to 52 months) and 100% respectively.

Conclusion

Neurocytomas are a rare clinical entity that warrants further investigation into molecular and pathologic prognosticating features. Methylation profiling may aid in differentiation of neurocytoma from other difficult to diagnose tumors who share similar histologic features.

Maturation of the sella turcica and parasellar region: Surgical relevance for anterior skull base approaches in pediatric patients

OBJECTIVE

Traditional and extended transnasal transsphenoidal approaches provide direct access to a variety of anterior skull base pathologies. Despite increased utilization of transnasal approaches in children, anatomic studies on pediatric skull base maturation are limited. We herein perform a surgically relevant morphometric analysis of the sella and parasellar regions during pediatric maturation.

METHODS

Measurements of sellar length (SL), sellar depth (SDp), sellar diameter (SDm), interclinoid distance (ID), intercavernous distance (ICD), and the presence of sphenoid sinus pneumatization (SSP), and sphenoid sinus type (SST) were made on thin-cut CT scans from 60 patients (evenly grouped by ages 0-3, 4-7, 8-11 12-15, 16-18, and >18 years) for analysis. Data were analyzed by sex and age groups using t-tests and linear regression.

RESULTS

Sella and parasellar parameters did not differ by sex. SL steadily increased from 8.5 ± 1.2 mm to 11.5 ± 1.6 mm throughout development. SDp and SDm increased from 6.0 ± 0.9 mm to 9.3 ± 1.4 mm and 9.0 ± 1.6 mm to 14.4 ± 1.8 mm during maturation, with significant interval growth from ages 16-18 to adult (p < 0.01). ID displayed significant growth from ages 0-3 to 4-7 (18.0 ± 2.4 mm to 20.7 ± 1.9 mm; p = 0.002) and ICD from ages 0-3 to 8-11 (12.0 ± 1.8 mm to 13.5 ± 2.1 mm; p < 0.001), without further significant interval growth. SSP was not seen in patients < 3, but was 100% by ages 8-11. SSTs progressed from conchal/presellar (60% at ages 4-7) to sellar/postsellar (80% at adulthood).

CONCLUSION

The sella and parasellar regions have varied growth patterns with development. Knowledge of the expected maturation of key anterior skull base structures may augment surgical planning in younger patients.

Microsurgical Resection of a Giant Posterior Fossa Aneurysmal Malformation in a 21-Month-Old

Pediatric aneurysms commonly occur in the vertebrobasilar circulation with complex morphologies.¹ "Aneurysmal malformations," or fistulous vessel dilations without a nidus, have also been described.² Vessel friability and sensitivity to blood loss can complicate surgery. A 21-month-old male with motor and speech delay was found to have a giant posterior fossa aneurysmal malformation. He was lethargic, with minimal speech, and moved all extremities with mild hypotonia. Imaging demonstrated a 6.9 × 5.1 × 4.6 cm aneurysm arising from a fenestrated right V4 segment. This communicated via a single connection with the deep venous system, draining through the superior vermian cistern veins, posterior mesencephalic vein, basal vein of Galen, and inferior sagittal sinus, consistent with an arteriovenous fistula with secondary aneurysmal dilatation. Endovascular sacrifice was not feasible, in addition to concern for swelling after embolization. Three-dimensional modeling confirmed close proximity of the single inflow and outflow tracts. A suboccipital and left far lateral craniotomy for clip trapping and excision of the aneurysmal arteriovenous malformation was performed in a lateral position to completely decompress the brainstem (Video 1). Angiography before closure and postoperative vascular imaging demonstrated complete aneurysmal resection and fistula disconnection, with patency of normal vasculature. The postoperative course was notable for transient swallowing difficulties likely from lower cranial nerve irritation and refractory hydrocephalus requiring a shunt. The patient was meeting all developmental milestones at 2-year follow-up. This case highlights the complex vascular pathology often seen in pediatric patients, as well as the importance of presurgical planning and careful microsurgical technique in achieving a successful outcome.

Management of pediatric clival chordoma with extension to the craniocervical junction and occipito-cervical fusion: illustrative case

BACKGROUND

Chordomas are rare malignant neoplasms that develop from the primitive notochord with < 5% of the tumors occurring in pediatric patients younger than the age of 20. Of these pediatric chordomas, those affecting the craniocervical junction (C1–C2) are even more rare; therefore, parameters for surgical management of these pediatric tumors are not well characterized.

OBSERVATIONS

In this case, a 3-year-old male was found to have a clival chordoma on imaging with extension to the craniocervical junction resulting in spinal cord compression. Endoscopic-assisted transoral transclival approach for clival tumor resection was performed first. As a second stage, the patient underwent a left-sided far lateral craniotomy and cervical laminectomy for resection of the skull base chordoma and instrumented fusion of the occiput to C3. He made excellent improvements in strength and dexterity during rehab and was discharged after 3 weeks.

LESSONS

In pediatric patients with chordoma with extension to the craniocervical junction and spinal cord compression, decompression with additional occipito-cervical fusion appears to offer a good clinical outcome. Fusion performed as a separate surgery before or at the same time as the initial tumor resection surgery may lead to better outcomes.

Atypical Giant Suprasellar Prolactinoma Presenting With Visual Field Changes in the Absence of Symptoms of Hyperprolactinemia

Prolactinomas are benign tumors that make up the majority of all pituitary adenoma cases and present most commonly in women. Prolactinomas presenting in adolescents and children, however, are extremely rare. We report a case of a 17-year-old male who presented with a six-month history of headaches and a previously unrecognized visual field deficit on examination. Neuroimaging revealed a large suprasellar tumor with imaging, more characteristic of a craniopharyngioma or suprasellar low-grade glioma impinging, on the left intracranial optic nerve causing right-sided hemianopsia. Due to the extensive mass effect and bitemporal hemianopsia on examination, the decision to proceed with initial surgical debulking was made following informed consent. A subtotal resection was performed where the pathology was consistent with a prolactinoma that correlated with markedly elevated prolactin (PRL) levels obtained pre and post-operatively that have not resulted until five days post procedure.

The patient was subsequently treated with dopamine agonist (DA) cabergoline therapy and is now five-years disease-free with normal neurological examination and no residual tumor on neuroimaging. DA therapy has shown high clinical efficacy and should be considered prior to any surgical intervention; however, extensive mass effect may appropriate surgical debulking to increase therapy efficacy. Our case highlights an atypical appearance of a giant prolactinoma that may mimic other more common suprasellar tumors, a presentation associated with unrecognized visual field deficits, and the importance of rapid turnaround testing for serum PRL that may aid in the upfront diagnosis and management of prolactinomas.

Maturation of the anterior petrous apex: surgical relevance for performance of the middle fossa transpetrosal approach in pediatric patients

OBJECTIVE

The middle fossa transpetrosal approach to the petroclival and posterior cavernous sinus regions includes removal of the anterior petrous apex (APA), an area well studied in adults but not in children. To this end, the authors performed a morphometric analysis of the APA region during pediatric maturation.

METHODS

Measurements of the distance from the clivus to the internal auditory canal (IAC; C-IAC), the distance of the petrous segment of the internal carotid artery (petrous carotid; PC) to the mesial petrous bone (MPB; PC-MPB), the distance of the PC to the mesial petrous apex (MPA; PC-MPA), and the IAC depth from the middle fossa floor (IAC-D) were made on thin-cut CT scans from 60 patients (distributed across ages 0-3, 4-7, 8-11, 12-15, 16-18, and > 18 years). The APA volume was calculated as a cylinder using C-IAC (length) and PC-MPB (diameter). APA pneumatization was noted. Data were analyzed by laterality, sex, and age.

RESULTS

APA parameters did not differ by laterality or sex. APA pneumatization was seen on 20 of 60 scans (33.3%) in patients ≥ 4 years. The majority of the APA region growth occurred by ages 8-11 years, with PC-MPA and PC-MPB increasing 15.9% (from 9.4 to 10.9 mm, p = 0.08) and 23.5% (from 8.9 to 11.0 mm, p < 0.01) between ages 0-3 and 8-11 years, and C-IAC increasing 20.7% (from 13.0 to 15.7 mm, p < 0.01) between ages 0-3 and 4-7 years. APA volume increased 79.6% from ages 0-3 to 8-11 years (from 834.3 to 1499.2 mm3, p < 0.01). None of these parameters displayed further significant growth. Finally, IAC-D increased 51.1% (from 4.3 to 6.5 mm, p < 0.01) between ages 0-3 and adult, without significant differences between successive age groups.

CONCLUSIONS

APA development is largely complete by the ages of 8-11 years. Knowledge of APA growth patterns may aid approach selection and APA removal in pediatric patients.

Optimizing international neurosurgical outreach missions: 15-year appraisal of operative skill transfer in Lima, Peru

Background:

While several medical outreach models have been designed and executed to alleviate the unmet need for international neurosurgical care, disparate strategies have evolved. There is a need to determine the optimal pediatric neurosurgical outreach model through which resources are efficiently utilized while imparting the largest possible impact on global health. This study evaluates the efficacy of an international pediatric neurosurgery outreach model at transferring operative skill in a sustainable and scalable manner in Lima, Peru over a 15-year duration.

Methods:

Three 1-week neurosurgical missions were carried out (2004–2006) in Lima, Peru to teach neuroendoscopic techniques and to provide equipment to host neurosurgeons, equipping the hosts to provide care to indigent citizens beyond the duration of the missions. Follow-up data were obtained over a 15 year span, with collaboration maintained over email, two in-person visits, and video-conferencing services.

Results:

Since the outreach missions in 2004–2006, the host neurosurgeons demonstrated sustainability of the neuroendoscopic instruction by independently performing neuroendoscopic operations on a growing caseload: at baseline, 0 cases were performed in 2003, but since 2012 and onwards, 40–45 cases have been performed annually. Scalability is illustrated by the fact that the institution established a rigorous neuroendoscopy training program to independently pass on the techniques to resident physicians.

Conclusion:

The described international pediatric neurosurgical outreach model, centered around teaching operative technique as opposed to solely providing care to citizens, allowed operative skill to be sustainably transferred to surgeons in Lima, Peru. Having served the neuroendoscopic needs of hundreds of citizens, the strategic design is replicable and should be mirrored by future medical endeavors seeking to substantially impact the deficit in global surgical care.

Palliative endoscopic third ventriculostomy for pediatric primary brain tumors: a single-institution case series

OBJECTIVE

Children with nonoperative brain tumors, such as diffuse intrinsic pontine gliomas (DIPGs), often have life-threatening hydrocephalus. Palliative shunting is common in such cases but can be complicated by hardware infection and mechanical failure. Endoscopic third ventriculostomy (ETV) is a minimally invasive alternative to treat hydrocephalus without implanted hardware. Herein, the authors report their institutional experience with palliative ETV for primary pediatric brain tumors.

METHODS

The authors conducted a retrospective review of consecutive patients who had undergone palliative ETV for hydrocephalus secondary to nonresectable primary brain tumors over a 10-year period at Rady Children's Hospital. Collected variables included age, sex, tumor type, tumor location, presence of leptomeningeal spread, use of a robot for ETV, complications, ETV Success Score (ETVSS), functional status, length of survival, and follow-up time. A successful outcome was defined as an ETV performed without clinically significant perioperative complications or secondary requirement for a new shunt.

RESULTS

Fifteen patients met the study inclusion criteria (11 males, 4 females; average age 7.9 years, range 0.8-21 years). Thirteen patients underwent manual ETV, and 2 patients underwent robotic ETV. Preoperative symptoms included gaze palsy, nausea/vomiting, headache, lethargy, hemiparesis, and seizures. Tumor types included DIPG (3), intraventricular/thalamic glioblastoma (2), and leptomeningeal spread of medulloblastoma (2), anaplastic oligo-/astrocytoma (2), rhabdoid tumor (2), primitive neuroectodermal tumor (1), ganglioglioma (1), pineoblastoma (1), and embryonal carcinoma (1). The mean preoperative ETVSS was 79 ± 8.8. There was 1 perioperative complication, a wound breakdown consistent with refractory hydrocephalus. The mean follow-up was 4.9 ± 5.5 months overall, and mean survival for the patients who died was 3.2 ± 3.6 months. Two patients remained alive at a mean follow-up of 15.7 months. Palliative ETV was successful in 7 patients (47%) and unsuccessful in 8 (53%). While patients with successful ETV were significantly older (11.9 ± 5.6 vs 4.4 ± 4.1 years, p = 0.010), there were no significant differences in preoperative ETVSS (p = 0.796) or postoperative survival (p = 0.476) between the successful and unsuccessful groups. Overall, functional outcomes were similar between the two groups; there was no significant difference in posttreatment Karnofsky Performance Status scores (68.6 ± 19.5 vs 61.3 ± 16.3, p = 0.454), suggesting that including ETV in the treatment algorithm did not worsen outcomes.

CONCLUSIONS

Palliative ETV is a safe and potentially efficacious treatment option in selected pediatric patients with hydrocephalus from nonoperative brain tumors. Close follow-up, especially in younger children, is required to ensure that patients with refractory symptoms receive appropriate secondary CSF diversion.

Improving Pediatric Neuro-Oncology Survival Disparities in the United States-Mexico Border Region: A Cross-Border Initiative Between San Diego, California, and Tijuana, Mexico

PURPOSE

Treatment of children with CNS tumors (CNSTs) demands a complex, interdisciplinary approach that is rarely available in low- and middle-income countries. We established the Cross-Border Neuro-Oncology Program (CBNP) between Rady Children's Hospital, San Diego (RCHSD), and Hospital General, Tijuana (HGT), Mexico, to provide access to neuro-oncology care, including neurosurgic services, for children with CNSTs diagnosed at HGT. Our purpose was to assess the feasibility of the CBNP across the United States-Mexico border and improve survival for children with CNSTs at HGT by implementing the CBNP.

PATIENTS AND METHODS

We prospectively assessed clinicopathologic profiles, the extent of resection, progression-free survival, and overall survival (OS) in children with CNSTs at HGT from 2010 to 2017.

RESULTS

Sixty patients with CNSTs participated in the CBNP during the study period. The most common diagnoses were low-grade glioma (24.5%) and medulloblastoma (22.4%). Of patients who were eligible for surgery, 49 underwent resection at RCHSD and returned to HGT for collaborative management. Gross total resection was achieved in 78% of cases at RCHSD compared with 0% at HGT (P < .001) and was a predictor of 5-year OS (hazard ratio, 0.250; 95% CI, 0.067 to 0.934; P = .024). Five-year OS improved from 0% before 2010 to 52% in 2017.

CONCLUSION

The CBNP facilitated access to complex neuro-oncology care for underserved children in Mexico through binational exchanges of resources and expertise. Survival for patients in the CBNP dramatically improved. Gross total resection at RCHSD was associated with higher OS, highlighting the critical role of experienced neurosurgeons in the treatment of CNSTs. The CBNP model offers an attractive alternative for children with CNSTs in low- and middle-income countries who require complex neuro-oncology care, particularly those in close proximity to institutions in high-income countries with extensive neuro-oncology expertise.

Surgical Relevance of Pediatric Anterior Clinoid Process Maturation for Anterior Skull Base Approaches

BACKGROUND

Removal of the anterior clinoid process (ACP) can expand anterior skull base surgical corridors. ACP development and anatomical variations are poorly defined in children.

OBJECTIVE

To perform a morphometric analysis of the ACP during pediatric maturation.

METHODS

Measurements of ACP base thickness (ACP-BT), midpoint thickness (ACP-MT), length (ACP-L), length from optic strut to ACP tip (ACP-OS), pneumatization (ACP-pneumo), and the presence of an ossified carotico-clinoid ligament (OCCL) or interclinoid ligament (OIL) were made from high-resolution computed-tomography scans from 60 patients (ages 0-3, 4-7, 8-11 12-15, 16-18, and >18 yr). Data were analyzed by laterality, sex, and age groups using t-tests and linear regression.

RESULTS

There were no significant differences in ACP parameters by laterality or sex, and no significant growth in ACP-BT or ACP-MT during development. From ages 0-3 yr to adult, mean ACP-L increased 49%, from 7.7 to 11.5 mm. The majority of ACP-L growth occurred in 2 phases between ages 0-3 to 8-11 and ages 16-18 to adult. Conversely, ACP-OS was stable from ages 0-3 to 8-11 but increased by 63% between ages 8-11 to adult. Variations in ACP morphology (OCCL/OIL/ACP-pneumo) were found in 15% (9/60) of scans. OCCL and OIL occurred in patients as young as 3 yrs, whereas ACP-pneumo was not seen in patients younger than 11 yrs.

CONCLUSION

The ACP demonstrates stable thickness and a complex triphasic elongation and remodeling pattern with development, the understanding of which may facilitate removal in patients <12. Clinically relevant ACP anatomic variations can occur at any age.

Arteriovenous malformation surgery in children: the Rady Children's Hospital experience (2002-2019)

PURPOSE

Compared to adult AVMs, there is a paucity of data on the microsurgical treatment of pediatric AVMs. We report our institutional experience with pediatric AVMs treated by microsurgical resection with or without endovascular embolization and radiation therapy.

METHODS

We retrospectively reviewed all patients ≤ 18 years of age with cerebral AVMs that underwent microsurgical resection at Rady Children's Hospital 2002-2019.

RESULTS

Eighty-nine patients met inclusion criteria. The mean age was 10.3 ± 5.0 years, and 56% of patients were male. In total, 72 (81%) patients presented with rupture. Patients with unruptured AVMs presented with headache (n = 5, 29.4%), seizure (n = 9, 52.9%), or incidental finding (n = 3, 17.7%). The mean presenting mRS was 2.8 ± 1.8. AVM location was lobar in 78%, cerebellar/brainstem in 15%, and deep supratentorial in 8%. Spetzler-Martin grade was I in 28%, II in 45%, III in 20%, IV in 6%, and V in 1%. Preoperative embolization was utilized in 38% of patients and more frequently in unruptured than ruptured AVMs (62% vs. 32%, p = 0.022). Radiographic obliteration was achieved in 76/89 (85.4%) patients. Complications occurred in 7 (8%) patients. Annualized rates of delayed rebleeding and recurrence were 1.2% and 0.9%, respectively. The mean follow-up was 2.8 ± 3.1 years. A good neurological outcome (mRS score ≤ 2) was obtained in 80.9% of patients at last follow-up and was improved relative to presentation for 75% of patients.

CONCLUSIONS

Our case series demonstrates high rates of radiographic obliteration and relatively low incidence of neurologic complications of treatment or AVM recurrence.

Rotation flap distraction osteogenesis for unicoronal synostosis

Unicoronal craniosynostosis is notoriously difficult to treat, with long-term studies demonstrating high rates of relapse and the need for reoperation using open fronto-orbital advancement. Applying the principles of distraction osteogenesis to cranial vault remodeling has demonstrated promising short-term results that compare favorably with traditional methods, with simultaneous correction of both frontofacial and endocranial morphology, along with significant increases in intracranial volume. Here, the authors demonstrate their technique for rotation flap distraction osteogenesis in the treatment of unicoronal synostosis and provide case examples.

The video can be found here: https://vimeo.com/519505008.

Clinical and Neuroimaging Features of Magnetic Resonance-Guided Stereotactic Laser Ablation for Newly Diagnosed and Recurrent Pediatric Brain Tumors: A Single Institutional Series

OBJECTIVE

We describe our single-institutional experience with magnetic resonance-guided stereotactic laser ablation (SLA) for the treatment of newly diagnosed and recurrent pediatric brain tumors.

METHODS

Eighteen consecutive ablation procedures were performed in 17 patients from March 2016-April 2020. Patient demographics, indications, procedures, neuroimaging features, and outcomes were reviewed retrospectively.

RESULTS

Seventeen patients (mean age of 11.4 years, 11 boys, 6 girls) underwent SLA with a mean follow-up of 24 months (range: 3-45 months). Tumor histologies included pilocytic astrocytoma (n = 5), ganglioglioma (n = 3), low-grade glioma not otherwise specified (n = 4), glioblastoma (n = 2), meningioma (n = 1), medulloblastoma (n = 1), and metastatic malignant peripheral nerve sheath tumor (n = 1). SLA was first-line therapy in 10 patients. Mean procedure duration including anesthesia time was 328 minutes (range: 244-529 minutes), and mean postoperative length of stay was 1.5 days (range 1-5 days). The complication rate was 29%, which included 3 patients who experienced postoperative motor changes, which resolved within several weeks of surgery, 1 patient with self-limited intraoperative bradycardia and hypotension, and 1 patient who died postoperatively due to intracranial hemorrhage from a distant lesion. Twelve of 17 patients had a neuroimaging response after SLA (4 complete responses, 8 partial responses, 1 stable disease). Percentage of tumor shrinkage from baseline ranged from 33%-100% (mean 75%). Patients with low-grade glioma exhibited the best responses to SLA (range 3%-100% decrease; mean 90%; 36% complete response rate).

CONCLUSIONS

SLA is a minimally invasive modality for the treatment of newly diagnosed and recurrent low-grade pediatric brain tumors. Low-grade glioma exhibited the best responses. Identification of ideal candidates for SLA, mitigation of perioperative complications, and demonstration of long-term outcomes need to be better defined in a clinical trial setting.

Pediatric Nasal Chondromesenchymal Tumors: Case Report and Review of the Literature

INTRODUCTION

Nasal chondromesenchymal tumors (NCMT) are rare benign neoplasms that usually present in children <1 year of age. They can display rapid growth and significant local bony remodeling that can mimic a malignant process. Of the ∼50 published cases to date, few have documented the need for neurosurgical intervention. We herein report a NCMT in an infant treated with a staged cranial and transnasal approach, as well as summarize the available literature on this pathology.

CASE REPORT

A newborn male with a compromised airway was noted to have a large sinonasal lesion. After stabilization, MRI demonstrated a 4-cm enhancing mass with diffuse sinus involvement and significant extension into the anterior cranial fossa, with displacement of the optic apparatus and hypothalamic pituitary axis. After an initial biopsy, the patient underwent a bifrontal craniofacial approach at 2 months of age, followed by a second-stage transnasal endoscopic approach at 15 months which resulted in a complete resection. There were no neurosurgical complications. Pathology was consistent with a NCMT.

DISCUSSION

Although rare, neurosurgical involvement is critical for the treatment of NCMTs with intracranial extension. Staged cranial and endonasal endoscopic approaches may be needed for complete resection of such lesions.

Influence of Pediatric Endoscopic Endonasal Skull Base Resections on Midface and Skull Base Development

OBJECTIVE

The purpose of this study is to use imaging data to determine if endoscopic endonasal surgery (EES) for skull base tumor resection interrupts skull base growth and development, resulting in an atrophic midface skeletal structure, compared to matched normal controls.

METHODS

Data were collected by a retrospective chart review done on children aged 16 years and below who underwent endoscopic tumor resection and had pre- and postoperative magnetic resonance imaging with relevant midface anatomy. 121 normal controls were matched to 20 EES patients by age and gender. Three measurements related to midface anatomy were taken from 1 sagittal T1 slice and 1 axial T2 slice of each scan. Statistical analysis was used to compare growth measures between cases and controls.

RESULTS

Twenty patients who underwent EES between November 2015 and April 2018 met our inclusion criteria. The mean age of the patients, 11 males and 9 females, was 10 years, and 8 patients (38%) were aged 7 years or younger. Six patients who had a high-flow CSF leak obtained a nasoseptal flap. A student T test and multivariate regression analysis found that EES did not affect midface and skull base growth. Among the variables assessed, age appears to be the only driver of growth.

CONCLUSION

There were no identified differences in craniofacial growth in pediatric patients undergoing EES for skull base tumor resection as compared to the control group. EES does not appear to significantly interfere with midface/skull base development and is a good surgical option for pediatric patients.

Robot-assisted stereotactic biopsy of pediatric brainstem and thalamic lesions

OBJECTIVE

Biopsies of tumors located in deep midline structures require highly accurate stereotaxy to safely obtain lesional tissue suitable for molecular and histological analysis. Versatile platforms are needed to meet a broad range of technical requirements and surgeon preferences. The authors present their institutional experience with the robotic stereotactic assistance (ROSA) system in a series of robot-assisted biopsies of pediatric brainstem and thalamic tumors.

METHODS

A retrospective analysis was performed of 22 consecutive patients who underwent 23 stereotactic biopsies of brainstem or thalamic lesions using the ROSA platform at Rady Children's Hospital in San Diego between December 2015 and January 2020.

RESULTS

The ROSA platform enabled rapid acquisition of lesional tissue across various combinations of approaches, registration techniques, and positioning. No permanent deficits, major adverse outcomes, or deaths were encountered. One patient experienced temporary cranial neuropathy, and 3 developed small asymptomatic hematomas. The diagnostic success rate of the ROSA system was 91.3%.

CONCLUSIONS

Robot-assisted stereotactic biopsy of these lesions may be safely performed using the ROSA platform. This experience comprises the largest clinical series to date dedicated to robot-assisted biopsies of brainstem and diencephalic tumors.

Functional Precision Medicine Identifies New Therapeutic Candidates for Medulloblastoma

Medulloblastoma is among the most common malignant brain tumors in children. Recent studies have identified at least four subgroups of the disease that differ in terms of molecular characteristics and patient outcomes. Despite this heterogeneity, most patients with medulloblastoma receive similar therapies, including surgery, radiation, and intensive chemotherapy. Although these treatments prolong survival, many patients still die from the disease and survivors suffer severe long-term side effects from therapy. We hypothesize that each patient with medulloblastoma is sensitive to different therapies and that tailoring therapy based on the molecular and cellular characteristics of patients' tumors will improve outcomes. To test this, we assembled a panel of orthotopic patient-derived xenografts (PDX) and subjected them to DNA sequencing, gene expression profiling, and high-throughput drug screening. Analysis of DNA sequencing revealed that most medulloblastomas do not have actionable mutations that point to effective therapies. In contrast, gene expression and drug response data provided valuable information about potential therapies for every tumor. For example, drug screening demonstrated that actinomycin D, which is used for treatment of sarcoma but rarely for medulloblastoma, was active against PDXs representing Group 3 medulloblastoma, the most aggressive form of the disease. Functional analysis of tumor cells was successfully used in a clinical setting to identify more treatment options than sequencing alone. These studies suggest that it should be possible to move away from a one-size-fits-all approach and begin to treat each patient with therapies that are effective against their specific tumor. SIGNIFICANCE: These findings show that high-throughput drug screening identifies therapies for medulloblastoma that cannot be predicted by genomic or transcriptomic analysis.

Middle fossa approach for a pediatric facial nerve meningioma

Pediatric cerebellopontine angle (CPA) meningiomas are extremely rare and are usually treated with a retrosigmoid surgical approach or radiation. The authors present the use of a middle fossa approach for the treatment of a symptomatic CPA meningioma in a 22-month-old female. The patient initially presented at 17 months with isolated progressive, long-standing right-sided facial weakness. MRI demonstrated a 5.0 × 5.0-mm right CPA lesion just superior to the cisternal segment of cranial nerve (CN) VII, which demonstrated growth on interval imaging. At 22 months of age she underwent a successful middle fossa craniotomy, including wide exposure of the porus acusticus, allowing for a gross-total resection with preservation of CNs VII and VIII. Pathological analysis revealed a WHO grade I meningioma. The patient remained neurologically stable on follow-up. The middle fossa approach can be used to safely access the CPA in properly selected pediatric patients.

A Paramedian Supracerebellar, Infratentorial Approach for Resection of Midbrain Tumor

Brainstem tumors represent formidable lesions for neurosurgical intervention. They should be approached with a thorough understanding of the anatomy and clear sense of surgical goals. A 14-year-old previously healthy girl presented with 2 weeks of nausea, headaches, diplopia, and gait instability. Workup revealed a 3.5 x 2.5 x 2.5 cm contrast-enhancing mass within the right midbrain. The patient consented to the surgical procedure. Preoperative imaging demonstrated superior displacement of the deep venous system because of the tumor, as well as inferior displacement of the fourth cranial nerve exit zone and posterior bowing of the entire tectal region. This allowed a safe corridor from a supracerebellar infratentorial approach. The three quarters lateral position was chosen to optimize surgeon ergonomics and allow for gravity to drain blood from the operative field. Near total resection was obtained without any new neurologic deficit. Final pathology was consistent with pilocytic astrocytoma, World Health Organization grade I. The video demonstrates the surgical approach in addition to techniques for brainstem tumor resection (Video 1).

Tumor necrosis factor overcomes immune evasion in p53-mutant medulloblastoma

Many immunotherapies act by enhancing the ability of cytotoxic T cells to kill tumor cells. Killing depends on T cell recognition of antigens presented by class I major histocompatibility complex (MHC-I) proteins on tumor cells. In this study, we showed that medulloblastomas lacking the p53 tumor suppressor do not express surface MHC-I and are therefore resistant to immune rejection. Mechanistically, this is because p53 regulates expression of the peptide transporter Tap1 and the aminopeptidase Erap1, which are required for MHC-I trafficking to the cell surface. In vitro, tumor necrosis factor (TNF) or lymphotoxin-β receptor agonist can rescue expression of Erap1, Tap1 and MHC-I on p53-mutant tumor cells. In vivo, low doses of TNF prolong survival and synergize with immune checkpoint inhibitors to promote tumor rejection. These studies identified p53 as a key regulator of immune evasion and suggest that TNF could be used to enhance sensitivity of tumors to immunotherapy.

Magnetic resonance-guided stereotactic laser ablation therapy for the treatment of pediatric brain tumors: a multiinstitutional retrospective study

OBJECTIVE

This study aimed to assess the safety and efficacy of MR-guided stereotactic laser ablation (SLA) therapy in the treatment of pediatric brain tumors.

METHODS

Data from 17 North American centers were retrospectively reviewed. Clinical, technical, and radiographic data for pediatric patients treated with SLA for a diagnosis of brain tumor from 2008 to 2016 were collected and analyzed.

RESULTS

A total of 86 patients (mean age 12.2 ± 4.5 years) with 76 low-grade (I or II) and 10 high-grade (III or IV) tumors were included. Tumor location included lobar (38.4%), deep (45.3%), and cerebellar (16.3%) compartments. The mean follow-up time was 24 months (median 18 months, range 3-72 months). At the last follow-up, the volume of SLA-treated tumors had decreased in 80.6% of patients with follow-up data. Patients with high-grade tumors were more likely to have an unchanged or larger tumor size after SLA treatment than those with low-grade tumors (OR 7.49, p = 0.0364). Subsequent surgery and adjuvant treatment were not required after SLA treatment in 90.4% and 86.7% of patients, respectively. Patients with high-grade tumors were more likely to receive subsequent surgery (OR 2.25, p = 0.4957) and adjuvant treatment (OR 3.77, p = 0.1711) after SLA therapy, without reaching significance. A total of 29 acute complications in 23 patients were reported and included malpositioned catheters (n = 3), intracranial hemorrhages (n = 2), transient neurological deficits (n = 11), permanent neurological deficits (n = 5), symptomatic perilesional edema (n = 2), hydrocephalus (n = 4), and death (n = 2). On long-term follow-up, 3 patients were reported to have worsened neuropsychological test results. Pre-SLA tumor volume, tumor location, number of laser trajectories, and number of lesions created did not result in a significantly increased risk of complications; however, the odds of complications increased by 14% (OR 1.14, p = 0.0159) with every 1-cm3 increase in the volume of the lesion created.

CONCLUSIONS

SLA is an effective, minimally invasive treatment option for pediatric brain tumors, although it is not without risks. Limiting the volume of the generated thermal lesion may help decrease the incidence of complications.

Keyhole Microsurgical Middle Fossa Arachnoid Cyst Fenestration: 2-Dimensional Operative Video

Surgical options for symptomatic intracranial arachnoid cysts include cyst shunting and microscopic or endoscopic fenestration.¹ We advocate a microsurgical keyhole approach for the durable fenestration of middle fossa arachnoid cysts, taking advantage of the superior magnification, depth perception, and illumination of the operating microscope, as well as the ability to use bimanual surgical technique and variable suction to ensure safe manipulation of arachnoid membranes and fenestration of these lesions into the deep cisterns.² Key technical aspects of this approach demonstrated in this video (Video 1) include performance of a dime-sized temporal craniotomy; strict microsurgical technique with sharp dissection via a No. 11 blade, sharp microdissectors, and microscissors; disruption of the arachnoid membranes overlying cranial nerves II/III, the internal carotid artery, and the posterior communicating artery; and fenestration of the membrane of Lilliquist through the opticocarotid, oculomotor, and/or supratrochlear triangles. The utility of this approach is illustrated by the case of a 5-year-old male with a history of headaches and interval progression of a left temporal grade 2 arachnoid cyst, who experienced symptom resolution and cyst shrinkage after keyhole microsurgical fenestration.

Rate-controlled intraventricular endoscopic irrigation via bipolar foot pedal activation: technical note

Irrigation during intraventricular endoscopic surgery is critical for visualization, with normal intracranial pressure maintained by balancing fluid ingress and egress. Although irrigation is typically achieved through manual manipulation of inexact stopcocks, the authors have developed a rate-controlled, foot pedal-activated system for precise intraventricular irrigation by using a standard irrigating bipolar electrocautery machine.This study is a retrospective review of patients who underwent endoscopic intraventricular surgery between January 1, 2018, and September 25, 2019, in which this irrigation system was used. Important components of this system include a bipolar module irrigation regulator that is set to a desired rate, a secure connection of the bipolar irrigation tubing to the endoscope, and one or more open egress ports on the endoscope for passive fluid drainage. Nineteen consecutive patients were identified on review (average age ± SD, 4.3 ± 4.1 years). Procedures performed included third ventriculostomies (n = 10); arachnoid/choroid cyst fenestrations/resections (n = 3); biopsy/tumor resection (n = 1); and combined procedures (n = 5). Foot pedal-controlled irrigation provided visualization of all intraventricular structures. A single operator was able to control the endoscope, endoscopic instruments, and irrigation, with assistance as indicated for more complex maneuvers. There were no perioperative complications. Because this setup is easily constructed from a standard irrigating bipolar machine, delivers precise irrigation flow rates, and facilitates a single-surgeon bimanual technique, these data support the utility of foot-controlled irrigation for endoscopic intraventricular surgery.