The role of neuromodulation in the management of drug-resistant epilepsy

Drug-resistant epilepsy (DRE) poses significant challenges in terms of effective management and seizure control. Neuromodulation techniques have emerged as promising solutions for individuals who are unresponsive to pharmacological treatments, especially for those who are not good surgical candidates for surgical resection or laser interstitial therapy (LiTT). Currently, there are three neuromodulation techniques that are FDA-approved for the management of DRE. These include vagus nerve stimulation (VNS), deep brain stimulation (DBS), and responsive neurostimulation (RNS). Device selection, optimal time, and DBS and RNS target selection can also be challenging. In general, the number and localizability of the epileptic foci, alongside the comorbidities manifested by the patients, substantially influence the selection process. In the past, the general axiom was that DBS and VNS can be used for generalized and localized focal seizures, while RNS is typically reserved for patients with one or two highly localized epileptic foci, especially if they are in eloquent areas of the brain. Nowadays, with the advance in our understanding of thalamic involvement in DRE, RNS is also very effective for general non-focal epilepsy. In this review, we will discuss the underlying mechanisms of action, patient selection criteria, and the evidence supporting the use of each technique. Additionally, we explore emerging technologies and novel approaches in neuromodulation, such as closed-loop systems. Moreover, we examine the challenges and limitations associated with neuromodulation therapies, including adverse effects, complications, and the need for further long-term studies. This comprehensive review aims to provide valuable insights on present and future use of neuromodulation.

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

OBJECTIVE

Congenital anomalies of the atlanto-occipital articulation may be present in patients with Chiari malformation type I (CM-I). However, it is unclear how these anomalies affect the biomechanical stability of the craniovertebral junction (CVJ) and whether they are associated with an increased incidence of occipitocervical fusion (OCF) following posterior fossa decompression (PFD). The objective of this study was to determine the prevalence of condylar hypoplasia and atlas anomalies in children with CM-I and syringomyelia. The authors also investigated the predictive contribution of these anomalies to the occurrence of OCF following PFD (PFD+OCF).

METHODS

The authors analyzed the prevalence of condylar hypoplasia and atlas arch anomalies for patients in the Park-Reeves Syringomyelia Research Consortium database who underwent PFD+OCF. Condylar hypoplasia was defined by an atlanto-occipital joint axis angle (AOJAA) ≥ 130°. Atlas assimilation and arch anomalies were identified on presurgical radiographic imaging. This PFD+OCF cohort was compared with a control cohort of patients who underwent PFD alone. The control group was matched to the PFD+OCF cohort according to age, sex, and duration of symptoms at a 2:1 ratio.

RESULTS

Clinical features and radiographic atlanto-occipital joint parameters were compared between 19 patients in the PFD+OCF cohort and 38 patients in the PFD-only cohort. Demographic data were not significantly different between cohorts (p > 0.05). The mean AOJAA was significantly higher in the PFD+OCF group than in the PFD group (144° ± 12° vs 127° ± 6°, p < 0.0001). In the PFD+OCF group, atlas assimilation and atlas arch anomalies were identified in 10 (53%) and 5 (26%) patients, respectively. These anomalies were absent (n = 0) in the PFD group (p < 0.001). Multivariate regression analysis identified the following 3 CVJ radiographic variables that were predictive of OCF occurrence after PFD: AOJAA ≥ 130° (p = 0.01), clivoaxial angle < 125° (p = 0.02), and occipital condyle-C2 sagittal vertical alignment (C-C2SVA) ≥ 5 mm (p = 0.01). A predictive model based on these 3 factors accurately predicted OCF following PFD (C-statistic 0.95).

CONCLUSIONS

The authors' results indicate that the occipital condyle-atlas joint complex might affect the biomechanical integrity of the CVJ in children with CM-I and syringomyelia. They describe the role of the AOJAA metric as an independent predictive factor for occurrence of OCF following PFD. Preoperative identification of these skeletal abnormalities may be used to guide surgical planning and treatment of patients with complex CM-I and coexistent osseous pathology.

Intramedullary spinal cord tumors in pediatric patients presenting later with brain lesions: case series and systematic review of the literature

PURPOSE

Intramedullary spinal cord tumors are an uncommon pathology in adults and children. Most descriptive studies of intramedullary spinal cord tumors have not focused on a possible association with future brain lesions. To the best of our knowledge, few reports describe this potential relationship. This is one of the most extensive case series of secondary brain lesions of intramedullary spinal cord tumors in the pediatric population.

METHODS

Retrospective chart review was performed on pediatric patients (21 years old and younger) who underwent resection of an intramedullary spinal cord tumor at two tertiary care hospitals from 2001 to 2020. Patients previously treated or diagnosed with spinal cord tumor, and subsequent development of intracranial manifestation of the same or different tumor, were included. Data regarding epidemiology, surgical intervention, and clinical and follow-up course were gathered. Data analysis was performed according to a standardized clinical protocol with a literature review.

RESULT

More than 500 patients underwent intradural spinal tumor resection surgeries at participating hospitals from 2001 to 2020. After excluding adult patients (older than 21 years old) and those with extramedullary lesions, 103 pediatric patients were identified who underwent resection of an intramedullary spinal cord tumor. Four underwent resection of an intermedullary tumor and later in their follow-up course developed a secondary intracranial neoplasm. In every case, the secondary neoplasm had the same pathology as the intramedullary tumor. Three of the patients had tumors at the cervico-thoracic junction, and one patient had a high cervical tumor. These patients had a negative primary workup for any metastatic disease at the time of the presentation or diagnosis. Complete and near complete resection was performed in three patients and subtotal in one patient.

CONCLUSION

Secondary brain tumors disseminated after initial spinal cord tumor are extremely rare. This study aims to allow specialists to better understand these pathologies and treat these rare tumors with more certainty and better expectations of unusual associated lesions and conditions.

Treatment of intramedullary spinal cord tumors: a modified Delphi technique of the North American Spine Society Section of Spine Oncology

OBJECTIVE

Intramedullary spinal cord tumors (IMSCTs) are rare tumors with heterogeneous presentations and natural histories that complicate their management. Standardized guidelines are lacking on when to surgically intervene and the appropriate aggressiveness of resection, especially given the risk of new neurological deficits following resection of infiltrative tumors. Here, the authors present the results of a modified Delphi method using input from surgeons experienced with IMSCT removal to construct a framework for the operative management of IMSCTs based on the clinical, radiographic, and tumor-specific characteristics.

METHODS

A modified Delphi technique was conducted using a group of 14 neurosurgeons experienced in IMSCT resection. Three rounds of written correspondence, surveys, and videoconferencing were carried out. Participants were queried about clinical and radiographic criteria used to determine operative candidacy and guide decision-making. Members then completed a final survey indicating their choice of observation or surgery, choice of resection strategy, and decision to perform duraplasty, in response to a set of patient- and tumor-specific characteristics. Consensus was defined as ≥ 80% agreement, while responses with 70%-79% agreement were defined as agreement.

RESULTS

Thirty-six total characteristics were assessed. There was consensus favoring surgical intervention for patients with new-onset myelopathy (86% agreement), chronic myelopathy (86%), or progression from mild to disabling numbness (86%), but disagreement for patients with mild numbness or chronic paraplegia. Age was not a determinant of operative candidacy except among frail patients, who were deemed more suitable for observation (93%). Well-circumscribed (93%) or posteriorly located tumors reaching the surface (86%) were consensus surgical lesions, and participants agreed that the presence of syringomyelia (71%) and peritumoral T2 signal change (79%) were favorable indications for surgery. There was consensus that complete loss of transcranial motor evoked potentials with a 50% decrease in the D-wave amplitude should halt further resection (93%). Preoperative symptoms seldom influenced choice of resection strategy, while a distinct cleavage plane (100%) or visible tumor-cord margins (100%) strongly favored gross-total resection.

CONCLUSIONS

The authors present a modified Delphi technique highlighting areas of consensus and agreement regarding surgical management of IMSCTs. Although not intended as a substitute for individual clinical decision-making, the results can help guide care of these patients. Additionally, areas of controversy meriting further investigation are highlighted.

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

OBJECTIVE

Lennox-Gastaut syndrome (LGS) is a severe form of epileptic encephalopathy, presenting during the first years of life, and is very resistant to treatment. Once medical therapy has failed, palliative surgeries such as vagus nerve stimulation (VNS) or corpus callosotomy (CC) are considered. Although CC is more effective than VNS as the primary neurosurgical treatment for LGS-associated drop attacks, there are limited data regarding the added value of CC following VNS. This study aimed to assess the effectiveness of CC preceded by VNS.

METHODS

This multinational, multicenter retrospective study focuses on LGS children who underwent CC before the age of 18 years, following prior VNS, which failed to achieve satisfactory seizure control. Collected data included epilepsy characteristics, surgical details, epilepsy outcomes, and complications. The primary outcome of this study was a 50% reduction in drop attacks.

RESULTS

A total of 127 cases were reviewed (80 males). The median age at epilepsy onset was 6 months (interquartile range [IQR] = 3.12-22.75). The median age at VNS surgery was 7 years (IQR = 4-10), and CC was performed at a median age of 11 years (IQR = 8.76-15). The dominant seizure type was drop attacks (tonic or atonic) in 102 patients. Eighty-six patients underwent a single-stage complete CC, and 41 an anterior callosotomy. Ten patients who did not initially have a complete CC underwent a second surgery for completion of CC due to seizure persistence. Overall, there was at least a 50% reduction in drop attacks and other seizures in 83% and 60%, respectively. Permanent morbidity occurred in 1.5%, with no mortality.

SIGNIFICANCE

CC is vital in seizure control in children with LGS in whom VNS has failed. Surgical risks are low. A complete CC has a tendency toward better effectiveness than anterior CC for some seizure types.

Outcomes of the early endoscopic-assisted suturectomy for treatment of multisuture craniosynostosis

To present the outcomes and adverse events associated with the endoscopic-assisted, minimally invasive suturectomy in patients with multisuture synostosis. This retrospective cohort study included children < 65 days of age who underwent endoscopic-assisted suturectomy (EAS) for multisuture craniosynostosis at a single tertiary referral center from 2013 to 2021. The primary outcome was calvarial expansion, and the secondary outcome was adverse events. The pre- and post-operative 3-dimensional brain computed tomography (CT) scan was used to calculate the intracranial volume and cephalic index. During a period of 2 years, 10 infants (10-64 days) diagnosed with multisuture synostosis underwent single-stage EAS of every affected suture in our center. The coronal suture was the most prevalent involved suture among our cases. The mean age and weight of the patients were 39 ± 17.5 days and 4.39 ± 0.8 kg, respectively. The surgical procedure took 42 ± 17.4 min of time and caused 46 ± 25.4 mL of bleeding on average. Ninety percent of the operations were considered successful (n = 9) regarding calvarial expansion. There were two complications, one requiring an open vault surgery and one repairing a leptomeningeal cyst. In the eight patients who did not necessitate further interventions, the mean pre-operative intracranial volume was 643.3 ± 189.4 cm3. The follow-up results within the average of 38.9 months after surgery showed that as age increases, the intracranial volume also increased significantly (R: 0.6, P < 0.0001), which suggests continued skull growth in patients who underwent EAS. With the low rate of intra- or post-operative complications and promising results on revising the restricted skull sutures, EAS seems both a safe and effective therapeutic modality in patients with multisuture synostosis, especially if completed in the first months after birth.

The evolution of spinal cord surgery: history, people, instruments, and results

INTRODUCTION

Spinal cord surgery has and always will be a challenging operation with satisfying results, but also with potentially devastating results. Over the last century, there has been an evolution in the way we perceive and conduct spinal cord surgery. The phenomenal evolution in technology from the very first x-ray pictures helps to localize the spinal pathology through the use of high-resolution MRI and ultrasonography that allows for high precision surgery with relatively minimal exposure.

METHODS

The advancements in the surgical technique and the utilization of neuromonitoring allow for maximal safe resection of these delicate and intricate tumors. We also are beginning to understand the biology of spinal cord tumors and vascular lesions, as in the recent 2021 WHO classification which identifies specific entities such as spinal ependymomas, MYCN-amplified, as separate entity from the other subtypes of ependymomas. Surgeons have also accepted the importance of maximal safe resection for most of the spinal cord pathologies rather than just performing biopsy and adjuvant treatment.

CONCLUSION

There have been significant advances since the first resection of an intramedullary tumor including diagnosis, imaging, and surgical technique for children. These advances have improved the prognosis and outcome in these children.

Knowledge Review of Spinal Deformity and the Need for Fusion and Fixation following Treatment for Spinal Tumors among the Pediatric Age Group

BACKGROUND

Spinal tumors are rare pathology in the pediatric population. The tumors can be classified as extradural, intradural extramedullary, or intramedullary. Any of the spinal tumors can eventually lead to spinal deformity. The progressive spinal deformity can be part of the initial presentation or evolve on long follow-up, even years after the initial intervention and treatment.

SUMMARY

Management of spinal deformity associated with spinal tumors in children is not well defined. Patients with progressive symptoms and even neurological deficits need correction for their deformity when diagnosed. Patients that do not have pain or related neurological deficits should be evaluated for the severity of their deformity and followed long-term. Special consideration is needed for young patients who need multilevel surgery or have deformity at presentation.

KEY MESSAGES

When considering the need for instrumentation and fusion, the surgeon should consider the age of the patient, expected future growth of the spine, neurologic status, extent of initial deformity, and the number of vertebral levels involved by tumor. Providers should also consider how surgery may fix or prevent deformity, especially when instrumentation can affect imaging at follow-up.

Endoscopic Placement of Intracystic Catheters: A Technical Note

BACKGROUND

Intraventricular neuroendoscopic surgery for tumor resection, biopsy, or cyst fenestration frequently requires precise placement of an intraventricular or intracystic catheter. Placement under direct visualization is not feasible because of small bore of working channel of the standard small ventriculoscope. Various techniques have been reported using a separate transcortical trajectory, endoluminal endoscope, or endovascular guide wire.

OBJECTIVE

To describe a technique allowing precise placement of intraventricular/intracystic catheter using a small bore working ventriculoscope, without need for additional equipment.

METHODS

Description of the technique including intraoperative photographs, video, and illustrative cases are provided.

RESULTS

The peel-away sheath is peeled off approximately 1 to 2 cm to allow for the shaft of the endoscope to pass past its tip. Ventricular access is gained using the peel-away sheath. After the stylet is removed, the peel-away sheath is not peeled further or stapled to the skin. The endoscope is introduced into the ventricle through the peel-away sheath. After the required intraventricular work is performed, the endoscope is maneuvered into the location of the desired catheter position. The peel-away sheath is slowly advanced over the stationary endoscope past its tip. While the peel-away sheath is being held in place, the endoscope is removed. After the catheter has been introduced into the peel-away sheath to a premeasured depth, the peel-away sheath is peeled and removed. The catheter is then connected to collection system, reservoir or shunt system.

CONCLUSION

The current technique allows for the precise placement of intraventricular/intracystic catheters without the need for additional equipment or a separate transcortical trajectory.

The Ribbon Sign as a Radiological Indicator of Intramedullary Spinal Cord Subependymomas

OBJECTIVE

Intramedullary spinal cord (IMSC) subependymomas are rare World Health Organization grade 1 ependymal tumors. The potential presence of functional neural tissue within the tumor and poorly demarcated planes presents a risk to resection. Anticipating a subependymoma on preoperative imaging can inform surgical decision-making and improve patient counseling. Here, we present our experience recognizing IMSC subependymomas on preoperative magnetic resonance imaging (MRI) based on a distinctive characteristic termed the "ribbon sign."

METHODS

We retrospectively reviewed preoperative MRIs of patients presenting with IMSC tumors at a large tertiary academic institution between April 2005 and January 2022. The diagnosis was confirmed histologically. The "ribbon sign" was defined as a ribbon-like structure of T2 isointense spinal cord tissue interwoven between regions of T2 hyperintense tumor. The ribbon sign was confirmed by an expert neuroradiologist.

RESULTS

MRIs from 151 patients were reviewed, including ten patients with IMSC subependymomas. The ribbon sign was demonstrated on nine (90%) patients with histologically proven subependymomas. Other tumor types did not display the ribbon sign.

CONCLUSION

The ribbon sign is a potentially distinctive imaging feature of IMSC subependymomas and indicates the presence of spinal cord tissue between eccentrically located tumor. Recognition of the ribbon sign should prompt clinicians to consider a diagnosis of subependymoma, aiding the neurosurgeon in planning the surgical approach and adjusting the surgical outcome expectation. Consequently, the risks and benefits of gross- vs. sub-total resection for palliative debulking should be carefully considered and discussed with patients.

Benign Spinal Tumors

Benign spinal intradural tumors are relatively rare and include intramedullary tumors with a favorable histology such as low-grade astrocytomas and ependymomas, as well as intradural extramedullary tumors such as meningiomas and schwannomas. The effect on the neural tissue is usually a combination of mass effect and neuronal involvement in cases of infiltrative tumors. The new understanding of molecular profiling of different tumors allowed us to better define central nervous system tumors and tailor treatment accordingly. The mainstay of management of many intradural spinal tumors is maximal safe surgical resection. This goal is more achievable with intradural extramedullary tumors; yet, with a meticulous surgical approach, many of the intramedullary tumors are amenable for safe gross-total or near-total resection. The nature of these tumors is benign; hence, a different way to measure outcome success is pursued and usually depends on functional rather than oncological or survival outcomes.

Malignant Spinal Tumors

Malignant spinal tumors constitute around 22% of all primary spinal tumors. The most common location of metastases to the spinal region is the extradural compartment. The molecular and genetic characterization of these tumors was the basis for the updated WHO classification of CNS tumors in 2016, where many CNS tumors are now diagnosed according to their genetic profile rather than relying solely on the histopathological appearance. Magnetic resonance imaging (MRI) is the current gold standard for the initial evaluation and subsequent follow-up on intradural spinal cord tumors, and the imaging sequences must include T2-weighted images (WI), short time inversion recovery (STIR), and pre- and post-contrast T1-WI in the axial, sagittal, and coronal planes. The clinical presentation is highly variable and depends on the tumor size, growth rate, type, infiltrative, necrotic and hemorrhagic potential as well as the exact location within the spinal compartment. Surgical intervention remains the mainstay of management of symptomatic and radiographically enlarging spinal tumors, where the goal is to achieve maximal safe resection. Tumor recurrences are managed with repeat surgical resection (preferred whenever possible and safe), radiotherapy, chemotherapy, or any combination of these therapies.

Surgical approaches to intramedullary spinal cord astrocytomas in the age of genomics

Intramedullary astrocytomas represent approximately 30%–40% of all intramedullary tumors and are the most common intramedullary tumor in children. Surgical resection is considered the mainstay of treatment in symptomatic patients with neurological deficits. Gross total resection (GTR) can be difficult to achieve as astrocytomas frequently present as diffuse lesions that infiltrate the cord. Therefore, GTR carries a substantial risk of new post-operative deficits. Consequently, subtotal resection and biopsy are often the only surgical options attempted. A midline or paramedian sulcal myelotomy is frequently used for surgical resection, although a dorsal root entry zone myelotomy can be used for lateral tumors. Intra-operative neuromonitoring using D-wave integrity, somatosensory, and motor evoked potentials is critical to facilitating a safe resection. Adjuvant radiation and chemotherapy, such as temozolomide, are often administered for high-grade recurrent or progressive lesions; however, consensus is lacking on their efficacy. Biopsied tumors can be analyzed for molecular markers that inform clinicians about the tumor’s prognosis and response to conventional as well as targeted therapeutic treatments. Stratification of intramedullary tumors is increasingly based on molecular features and mutational status. The landscape of genetic and epigenetic mutations in intramedullary astrocytomas is not equivalent to their intracranial counterparts, with important difference in frequency and type of mutations. Therefore, dedicated attention is needed to cohorts of patients with intramedullary tumors. Targeted therapeutic agents can be designed and administered to patients based on their mutational status, which may be used in coordination with traditional surgical resection to improve overall survival and functional status.

A novel online calculator to predict nonroutine discharge, length of stay, readmission, and reoperation in patients undergoing surgery for intramedullary spinal cord tumors

BACKGROUND CONTEXT

Intramedullary spinal cord tumors (IMSCTs) are rare tumors associated with significant morbidity and mortality. Surgical resection is often indicated for symptomatic lesions but may result in new neurological deficits and decrease quality of life. Identifying predictors of these adverse outcomes may help target interventions designed to reduce their occurrence. Nonetheless, most prior studies have employed population-level datasets with limited granularity.

PURPOSE

To determine independent predictors of nonroutine discharge, prolonged length of stay (LOS), and 30 day readmission and reoperation, and to deploy these results as a web-based calculator.

STUDY DESIGN

Retrospective cohort study PATIENT SAMPLE: A total of 235 patients who underwent resection of IMSCTs at a single comprehensive cancer center.

OUTCOME MEASURES

Nonroutine discharge, prolonged LOS, 30 day readmission, and 30 day reoperation METHODS: Patients who underwent surgery from June 2002 to May 2020 at a single tertiary center were included. Data was collected on patient demographics, clinical presentation, tumor histology, surgical procedures, and 30 day readmission and reoperation. Functional status was assessed using the Modified McCormick Scale (MMS) and queried preoperative neurological symptoms included weakness, urinary and bowel dysfunction, numbness, and back and radicular pain. Variables significant on univariable analysis at the α≤0.15 level were entered into a stepwise multivariable logistic regression model.

RESULTS

Of 235 included cases, 131 (56%) experienced a nonhome discharge and 68 (29%) experienced a prolonged LOS. Of 178 patients with ≥ 30 days of follow-up, 17 (9.6%) were readmitted within 30 days and 13 (7.4%) underwent reoperation. Wound dehiscence (29%) was the most common reason for readmission. Nonhome discharge was independently predicted by older age (OR=1.03/year; p<.01), thoracic location of the tumor (OR=2.36; p=.01), presenting with bowel dysfunction (OR=4.09; p=.03), and longer incision length (OR=1.44 per level; p=.03). Independent predictors of prolonged LOS included presenting with urinary incontinence (OR=2.65; p=.05) or a higher preoperative white blood cell count (OR=1.08 per 10³/μL); p=.01), while GTR predicted shorter LOS (OR=0.40; p=.02). Independent predictive factors for 30 day unplanned readmission included experiencing ≥1 complications during the first hospitalization (OR=6.13; p<.01) and having a poor (A-C) versus good (D-E) baseline neurological status on the ASIA impairment scale (OR=0.23; p=.03). The only independent predictor of unplanned 30 day reoperation was experiencing ≥1 inpatient complications during the index hospitalization (OR=6.92; p<.01). Receiver operating curves for the constructed models produced C-statistics of 0.67-0.77 and the models were deployed as freely available web-based calculators (https://jhuspine5.shinyapps.io/Intramedullary30day).

CONCLUSIONS

We found that neurological presentation, patient demographics, and incision length were important predictors of adverse perioperative outcomes in patients with IMSCTs. The calculators can be used by clinicians for risk stratification, preoperative counseling, and targeted interventions.

Predictors of survival and time to progression following operative management of intramedullary spinal cord astrocytomas

PURPOSE

Surgical resection is considered standard of care for primary intramedullary astrocytomas, but the infiltrative nature of these lesions often precludes complete resection without causing new post-operative neurologic deficits. Radiotherapy and chemotherapy serve as potential adjuvants, but high-quality data evaluating their efficacy are limited. Here we analyze the experience at a single comprehensive cancer center to identify independent predictors of postoperative overall and progression-free survival.

METHODS

Data was collected on patient demographics, tumor characteristics, pre-operative presentation, resection extent, long-term survival, and tumor progression/recurrence. Kaplan-Meier curves modeled overall and progression-free survival. Univariable and multivariable accelerated failure time regressions were used to compute time ratios (TR) to determine predictors of survival.

RESULTS

94 patients were included, of which 58 (62%) were alive at last follow-up. On multivariable analysis, older age (TR = 0.98; p = 0.03), higher tumor grade (TR = 0.12; p < 0.01), preoperative back pain (TR = 0.45; p < 0.01), biopsy [vs GTR] (TR = 0.18; p = 0.02), and chemotherapy (TR = 0.34; p = 0.02) were significantly associated with poorer survival. Higher tumor grade (TR = 0.34; p = 0.02) and preoperative bowel dysfunction (TR = 0.31; p = 0.02) were significant predictors of shorter time to detection of tumor growth.

CONCLUSION

Tumor grade and chemotherapy were associated with poorer survival and progression-free survival. Chemotherapy regimens were highly heterogeneous, and randomized trials are needed to determine if any optimal regimens exist. Additionally, GTR was associated with improved survival, and patients should be counseled about the benefits and risks of resection extent.

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

OBJECTIVE

The aim of this study was to determine differences in complications and outcomes between posterior fossa decompression with duraplasty (PFDD) and without duraplasty (PFD) for the treatment of pediatric Chiari malformation type I (CM1) and syringomyelia (SM).

METHODS

The authors used retrospective and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM1-SM who received PFD or PFDD and had at least 1 year of follow-up data. Preoperative, treatment, and postoperative characteristics were recorded and compared between groups.

RESULTS

A total of 692 patients met the inclusion criteria for this database study. PFD was performed in 117 (16.9%) and PFDD in 575 (83.1%) patients. The mean age at surgery was 9.86 years, and the mean follow-up time was 2.73 years. There were no significant differences in presenting signs or symptoms between groups, although the preoperative syrinx size was smaller in the PFD group. The PFD group had a shorter mean operating room time (p < 0.0001), fewer patients with > 50 mL of blood loss (p = 0.04), and shorter hospital stays (p = 0.0001). There were 4 intraoperative complications, all within the PFDD group (0.7%, p > 0.99). Patients undergoing PFDD had a 6-month complication rate of 24.3%, compared with 13.7% in the PFD group (p = 0.01). There were no differences between groups for postoperative complications beyond 6 months (p = 0.33). PFD patients were more likely to require revision surgery (17.9% vs 8.3%, p = 0.002). PFDD was associated with greater improvements in headaches (89.6% vs 80.8%, p = 0.04) and back pain (86.5% vs 59.1%, p = 0.01). There were no differences between groups for improvement in neurological examination findings. PFDD was associated with greater reduction in anteroposterior syrinx size (43.7% vs 26.9%, p = 0.0001) and syrinx length (18.9% vs 5.6%, p = 0.04) compared with PFD.

CONCLUSIONS

PFD was associated with reduced operative time and blood loss, shorter hospital stays, and fewer postoperative complications within 6 months. However, PFDD was associated with better symptom improvement and reduction in syrinx size and lower rates of revision decompression. The two surgeries have low intraoperative complication rates and comparable complication rates beyond 6 months.

Complex craniosynostosis in the context of Carpenter's syndrome

Carpenter's syndrome or acrocephalopolysyndactyly type II is a rare genetic autosomal recessive disease, with an incidence estimated at 1 per 1 million births. Common findings of a brachydactyly, polysyndactyly, and a trefoil-like skull with extreme brachycephaly due to fusion of the bilateral coronal, sagittal and lambdoid sutures. We report a 12-month-old male who was referred to our care for evaluation of a craniofacial deformity-a trefoil-like skull, flattened and receding forehead, bulging of temporal bones, hypertelorism, exorbitism, and polysyndactyly in the upper and lower limbs and psychomotor delay. Head computed tomography (CT) with 3D reconstruction revealed craniosynostosis with fusion of the coronal, metopic, and sagittal sutures. Correction of the craniofacial deformity was performed with satisfactory aesthesis of the craniofacial bones at 2 years of follow-up. Early correction of craniofacial deformity in Carpenter's syndrome is usually safe within 6 to 12 months. Venous drainage abnormalities and ectatic emissary veins can lead to significant bleeding and may be detected on MR angiography. Significant skull weakening may lead to bony fragmentation while creating cranial flaps and is best evaluated with 3D CT imaging. Taking these pitfalls into consideration decreases the chances of aborting the surgery and may lead to better overall outcomes.

Clinical features and surgical outcomes of intracranial and spinal cord subependymomas

OBJECTIVE

Subependymomas are low-grade ependymal tumors whose clinical characteristics, radiographic features, and postsurgical outcomes are incompletely characterized due to their rarity. The authors present an institutional case series and a systematic literature review to achieve a better understanding of subependymomas.

METHODS

Adult patients with histologically confirmed subependymoma or mixed subependymoma-ependymoma surgically treated at a tertiary hospital between 1992 and 2020 were identified. A systematic literature review of the PubMed, Embase, Web of Science, and Google Scholar databases from inception until December 4, 2020, was conducted according to PRISMA guidelines. Data extracted from both groups included demographics, radiographic features, tumor characteristics, management, and follow-up variables.

RESULTS

Forty-eight unique patients with subependymoma were identified by chart review; of these patients, 8 (16.7%) had mixed subependymoma-ependymoma tumors. The median age at diagnosis was 49 years (IQR 19.8 years), and 26 patients (54.2%) were male. Forty-two patients (87.5%) had intracranial subependymomas, and 6 (12.5%) had spinal tumors. The most common presentation was headache (n = 20, 41.7%), although a significant number of tumors were diagnosed incidentally (n = 16, 33.3%). Among the 42 patients with intracranial tumors, 15 (35.7%) had hydrocephalus, and the most common surgical strategy was a suboccipital approach with or without C1 laminectomy (n = 26, 61.9%). Gross-total resection (GTR) was achieved in 33 cases (68.7%), and 2 patients underwent adjuvant radiotherapy. Most patients had no major postsurgical complications (n = 34, 70.8%), and only 1 (2.1%) had recurrence after GTR. Of 2036 reports initially identified in the systematic review, 39 were eligible for inclusion, comprising 477 patients. Of 462 patients for whom tumor location was reported, 406 (87.9%) were intracranial, with the lateral ventricle as the most common location (n = 214, 46.3%). Spinal subependymomas occurred in 53 patients (11.5%), with 3 cases (0.6%) in multiple locations. Similar to the case series at the authors' institution, headache was the most common presenting symptom (n = 231, 54.0%) among the 428 patients whose presentation was reported. Twenty-seven patients (6.3%) were diagnosed incidentally, and 36 cases (8.4%) were found at autopsy. Extent of resection was reported for 350 patients, and GTR was achieved in 250 (71.4%). Fifteen of 337 patients (4.5%) had recurrence or progression.

CONCLUSIONS

The authors' case series and literature review demonstrate that patients with subependymoma are well managed with resection and generally have a favorable prognosis.

Impact of international research fellows in neurosurgery: results from a single academic center

OBJECTIVE

International research fellows have been historically involved in academic neurosurgery in the United States (US). To date, the contribution of international research fellows has been underreported. Herein, the authors aimed to quantify the academic output of international research fellows in the Department of Neurosurgery at The Johns Hopkins University School of Medicine.

METHODS

Research fellows with Doctor of Medicine (MD), Doctor of Philosophy (PhD), or MD/PhD degrees from a non-US institution who worked in the Hopkins Department of Neurosurgery for at least 6 months over the past decade (2010-2020) were included in this study. Publications produced during fellowship, number of citations, and journal impact factors (IFs) were analyzed using ANOVA. A survey was sent to collect information on personal background, demographics, and academic activities.

RESULTS

Sixty-four international research fellows were included, with 42 (65.6%) having MD degrees, 17 (26.6%) having PhD degrees, and 5 (7.8%) having MD/PhD degrees. During an average 27.9 months of fellowship, 460 publications were produced in 136 unique journals, with 8628 citations and a cumulative journal IF of 1665.73. There was no significant difference in total number of publications, first-author publications, and total citations per person among the different degree holders. Persons holding MD/PhDs had a higher number of citations per publication per person (p = 0.027), whereas those with MDs had higher total IFs per person (p = 0.048). Among the 43 (67.2%) survey responders, 34 (79.1%) had nonimmigrant visas at the start of the fellowship, 16 (37.2%) were self-paid or funded by their country of origin, and 35 (81.4%) had mentored at least one US medical student, nonmedical graduate student, or undergraduate student.

CONCLUSIONS

International research fellows at the authors' institution have contributed significantly to academic neurosurgery. Although they have faced major challenges like maintaining nonimmigrant visas, negotiating cultural/language differences, and managing self-sustainability, their scientific productivity has been substantial. Additionally, the majority of fellows have provided reciprocal mentorship to US students.

Neuroendoscopic Transventricular Approach for Cystic Craniopharyngioma

The literature is rich with many studies reporting different treatment modalities and approaches for cystic craniopharyngioma (CC), including microsurgery, neuroendoscopic transventricular approach, endoscopic transnasal surgery, stereotactic drainage, and Ommaya reservoir insertion. The goals of this manuscript are to report the successful treatment of an atypical case of CC using the neuroendoscopic transventricular approach (NTVA) as well as discuss the different surgical modalities for these tumors following a comprehensive review of the literature. Our patient is a nine-year-old female with a large CC who was managed using the NTVA. No complications or recurrence occurred over two years of follow-up. Results of our literature review showed lower recurrence and complication rates of the NTVA compared to other surgical modalities.The NTVA is potentially efficient, reliable, and safe for managing CC and cystic-dominant craniopharyngiomas, with low recurrence and complication rates compared to microsurgery and Ommaya reservoir insertion. Future randomized clinical studies comparing the various treatment modalities of CC are needed to solidify these conclusions.

Spontaneous regression of multiple intracranial capillary hemangiomas in a newborn-long-term follow-up and literature review

BACKGROUND

Intracranial capillary hemangiomas (ICHs) have a natural history and behavior that is very different from intracranial cavernous malformations. The literature is not consistent as to the best management strategy for ICHs.

CASE DESCRIPTION

Our patient is a 40-day-old male infant who presented with progressive increase in head circumference and multiple cutaneous capillary and ICHs. Obstructive hydrocephalus necessitated urgent cerebrospinal fluid (CSF) diversion, but no other surgical intervention was pursued due to the high risk-to-benefit ratio. All intracranial lesions spontaneously regressed by 11 years of age, albeit at a slower speed than the cutaneous lesions, with no functional or cognitive sequelae. We conducted a comprehensive literature review and provided a summary of all reported ICH cases.

CONCLUSION

Asymptomatic patients with ICHs are best approached with close follow-up and serial imaging studies as the potential for spontaneous regression is relatively high. Patients with isolated lesions or unclear diagnoses may benefit from a stereotactic biopsy, and surgical resection should be reserved for symptomatic lesions only.

Exoscope aided trans-sulcal minimally invasive parafascicular resection of a paediatric brainstem pilocytic astrocytoma using a tubular retractor system

The surgical management of brainstem glioma is challenging and has significant morbidity. Advances in surgical armamentarium has presented the opportunity to tackle these lesions. We present the case of a paediatric patient with a 2.3cm midbrain pilocytic astrocytoma. With the aid of tractography, neuro-navigation, 3-dimensional exoscope and a tubular retractor, near total resection of the tumour was achieved through a trans-sulcal para-fascicular approach without permanent injury to the corticospinal tract. To our knowledge this is the first report of a brainstem tumour resected using this approach and demonstrates what can be achieved with synergistic utility of evolving technologies in neurosurgery.

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

OBJECTIVE

Drug-resistant epilepsy (DRE) during the first few months of life is challenging and necessitates aggressive treatment, including surgery. Because the most common causes of DRE in infancy are related to extensive developmental anomalies, surgery often entails extensive tissue resections or disconnection. The literature on "ultra-early" epilepsy surgery is sparse, with limited data concerning efficacy controlling the seizures, and safety. The current study's goal is to review the safety and efficacy of ultra-early epilepsy surgery performed before the age of 3 months.

METHODS

To achieve a large sample size and external validity, a multinational, multicenter retrospective study was performed, focusing on epilepsy surgery for infants younger than 3 months of age. Collected data included epilepsy characteristics, surgical details, epilepsy outcome, and complications.

RESULTS

Sixty-four patients underwent 69 surgeries before the age of 3 months. The most common pathologies were cortical dysplasia (28), hemimegalencephaly (17), and tubers (5). The most common procedures were hemispheric surgeries (48 procedures). Two cases were intentionally staged, and one was unexpectedly aborted. Nearly all patients received blood products. There were no perioperative deaths and no major unexpected permanent morbidities. Twenty-five percent of patients undergoing hemispheric surgeries developed hydrocephalus. Excellent epilepsy outcome (International League Against Epilepsy [ILAE] grade I) was achieved in 66% of cases over a median follow-up of 41 months (19-104 interquartile range [IQR]). The number of antiseizure medications was significantly reduced (median 2 drugs, 1-3 IQR, p < .0001). Outcome was not significantly associated with the type of surgery (hemispheric or more limited resections).

SIGNIFICANCE

Epilepsy surgery during the first few months of life is associated with excellent seizure control, and when performed by highly experienced teams, is not associated with more permanent morbidity than surgery in older infants. Thus surgical treatment should not be postponed to treat DRE in very young infants based on their age.

Pediatric mild head trauma: is outpatient follow-up imaging necessary or beneficial?

OBJECTIVE

Pediatric traumatic brain injury (TBI) is the leading cause of death among children and is a significant cause of morbidity. However, the majority of injuries are mild (Glasgow Coma Scale score 13-15) without any need for neurosurgical intervention, and clinically significant neurological decline rarely occurs. Although the question of repeat imaging within the first 24 hours has been discussed in the past, the yield of short-term follow-up imaging has never been thoroughly described. In this paper, the authors focus on the yield of routine repeat imaging for pediatric mild TBI (mTBI) at the first clinic visit following hospital discharge.

METHODS

The authors conducted a retrospective review of patients with pediatric brain trauma who had been admitted to Johns Hopkins All Children's Hospital (JHACH). Patients with mTBI were identified, and their presentation, hospital course, and imaging results were reviewed. Those pediatric patients with mTBI who had undergone no procedure during their initial admission (only conservative treatment) were eligible for inclusion in the study. Two distinct groups were identified: patients who underwent repeated imaging at their follow-up clinic visit and those who underwent only clinical evaluation. Each case was assessed on whether the follow-up imaging had changed the follow-up course.

RESULTS

Between 2010 and 2015, 725 patients with TBI were admitted to JHACH. Of those, 548 patients qualified for analysis (i.e., those with mTBI who received conservative treatment without any procedure and were seen in the clinic for follow-up evaluation within 8 weeks after the trauma). A total of 392 patients had only clinic follow-up, without any diagnostic imaging study conducted as part of their clinic visit, whereas the other 156 patients underwent repeat MRI. Only 1 patient had a symptomatic change and was admitted after undergoing imaging. For 30 patients (19.2%), it was decided after imaging to continue the neurosurgical follow-up, which is a change from the institutional paradigm after mTBI. None of these patients had a change in neurological status, and all had a good functional status. All of these patients had one more follow-up in the clinic with new MRI, and none of them required further follow-up.

CONCLUSIONS

Children with mTBI are commonly followed up in the ambulatory clinic setting. The authors believe that for children with mTBI, normal clinical examination, and no new symptoms, there is no need for routine ambulatory imaging since the clinical yield of such is relatively low.

Split cord malformation and tethered cord syndrome: case series with long-term follow-up and literature review

PURPOSE

To date, the description of the natural course of concurrent tethered cord syndrome with a low-lying conus medullaris and split cord malformation is lacking in the literature. We report a cohort of adult and pediatric patients with concurrent malformations and long-term follow-up.

METHODS

Patients with concurrent diagnoses of split cord malformation and tethered cord (radiographic evidence supporting clinical symptomatology) were identified between 2000 and 2020. Patients without sufficient documentation or at least 6-month follow-up were excluded.

RESULTS

Nine patients were identified with an average of 8.9 years follow-up (range 2-31 years). The most common symptoms were radiating leg pain and lower extremity paresthesias, occurring in 44% of patients; and bladder/bowel dysfunction, worsening scoliosis, and acute motor deterioration were less common. Two patients were successfully treated conservatively for mild leg pain and paresthesias. For those who underwent surgery, all experienced symptomatic relief upon first follow-up. Two had late symptomatic recurrence; one 4 and 8 years after initial surgery; and the other, 11, 26, and 31 years after initial surgery.

CONCLUSION

The rarity of concurrent split cord and tethered cord syndrome with a low-lying conus makes management difficult to formulate. This series supplements our knowledge of the long-term outcomes and lessons learned from the management of these patients. Approximately 25% of patients were managed conservatively and had symptomatic improvement. For surgically managed patients, with intractable pain or worsening neurological function, symptoms can still recur over a decade after intervention. Reoperation, however, can still be beneficial, can provide years of relief, and should be considered.

Adolescent Disc Disease: Risk Factors and Treatment Success-Related Factors

OBJECTIVE

A paucity of literature is available discussing the associated risk factors, treatment options (including the use of minimally invasive surgery), and outcomes related to lumbar disc herniation (LDH) in children. We have discussed the risk factors for disc disease among pediatric patients and evaluated the efficacy of the minimally invasive approach.

METHODS

A retrospective review of pediatric patients with lumbar disc disease who had undergone microdiscectomy at our institution from 2005 to 2016 was conducted. The preoperative presentation, hospital course, postoperative course, and follow-up data (≥3 years) were reviewed. We evaluated the risk factors for LDH and the surgical outcomes for both groups.

RESULTS

A total of 52 pediatric patients had undergone 61 lumbar disc surgeries for LDH in our department from 2005 to 2016. Their average age at surgery was 16.65 years. Of the 61 procedures, 48 (78.7%) had been performed via the minimally invasive spine microdiscectomy approach and 13 (21.3%) via the open microdiscectomy approach. The average body mass index for all cases was 29.3 kg/m². The average interval to diagnosis was 7.9 months. Of the 61 cases, 21 (34.4%) had been required for patients who were competitive athletes. In addition, 15 had been for LDH related to trauma (24.6%). In 46 of the 61 cases, complete resolution of the symptoms had occurred at the 1-year follow-up visit (79.2% of minimally invasive spine microdiscectomy vs 61.5% of open microdiscectomy).

CONCLUSION

Risk factors similar to those for adult LDH, such as an elevated body mass index, can be seen in the pediatric population. However, some unique risk factors such as post-traumatic LDH were found in the pediatric age group. Minimally invasive techniques are demonstrably safe and useful in this patient population.

Transcriptional analyses of adult and pediatric adamantinomatous craniopharyngioma reveals similar expression signatures regarding potential therapeutic targets

Adamantinomatous craniopharyngioma (ACP) is a biologically benign but clinically aggressive lesion that has a significant impact on quality of life. The incidence of the disease has a bimodal distribution, with peaks occurring in children and older adults. Our group previously published the results of a transcriptome analysis of pediatric ACPs that identified several genes that were consistently overexpressed relative to other pediatric brain tumors and normal tissue. We now present the results of a transcriptome analysis comparing pediatric to adult ACP to identify biological differences between these groups that may provide novel therapeutic insights or support the assertion that potential therapies identified through the study of pediatric ACP may also have a role in adult ACP. Using our compiled transcriptome dataset of 27 pediatric and 9 adult ACPs, obtained through the Advancing Treatment for Pediatric Craniopharyngioma Consortium, we interrogated potential age-related transcriptional differences using several rigorous mathematical analyses. These included: canonical differential expression analysis; divisive, agglomerative, and probabilistic based hierarchical clustering; information theory based characterizations; and the deep learning approach, HD Spot. Our work indicates that there is no therapeutically relevant difference in ACP gene expression based on age. As such, potential therapeutic targets identified in pediatric ACP are also likely to have relvance for adult patients.

Symptomatic Recurrence of Cervical Spine Myelomeningocele in an Adult Patient

BACKGROUND

Cervical myelomeningocele (MMC) is a very rare neural type defect that is usually discovered and managed in childhood. It is best described as a closed type of spinal dysraphism, where the posterior portion of the cervical thecal sac forms a pouch that bulges out through a narrow posterior spina bifida and contains spinal neural tissue with or without cerebrospinal fluid.

CASE DESCRIPTION

We report a 47-year-old male patient who presented with neck pain and decreased ability to use his fingers that had progressed over 3 years before presentation. Cervical spine magnetic resonance imaging revealed a posterior bulge between the spinous processes of C4 and C6, absence of the spinous process of C5, and presence of cerebrospinal fluid and spinal cord tissue and nerve roots within the bulging sac, suggestive of MMC. Simple untethering of the cord tissue was sufficient to halt the progression and allow for improvement in neurological deficits.

CONCLUSION

Cervical MMC is extremely rare in adults, the symptomatic progression of which is most likely because of cord tethering by fibrotic tissue formation over years. Early surgical correction and release of the tethered cord is relatively safe and prevents the evolution of neurological symptoms.

Genomic Landscape of Intramedullary Spinal Cord Gliomas

Intramedullary spinal cord tumors (IMSCTs) are rare neoplasms that have limited treatment options and are associated with high rates of morbidity and mortality. To better understand the genetic basis of these tumors we performed whole exome sequencing on 45 tumors and matched germline DNA, including twenty-nine spinal cord ependymomas and sixteen astrocytomas. Though recurrent somatic mutations in IMSCTs were rare, we identified NF2 mutations in 15.7% of tumors (ependymoma, N = 7; astrocytoma, N = 1), RP1 mutations in 5.9% of tumors (ependymoma, N = 3), and ESX1 mutations in 5.9% of tumors (ependymoma, N = 3). We further identified copy number amplifications in CTU1 in 25% of myxopapillary ependymomas. Given the paucity of somatic driver mutations, we further performed whole-genome sequencing of 12 tumors (ependymoma, N = 9; astrocytoma, N = 3). Overall, we observed that IMSCTs with intracranial histologic counterparts (e.g. glioblastoma) did not harbor the canonical mutations associated with their intracranial counterparts. Our findings suggest that the origin of IMSCTs may be distinct from tumors arising within other compartments of the central nervous system and provides the framework to begin more biologically based therapeutic strategies.

Scoliosis in patients with Chiari malformation type I

The literature about the association between Chiari malformations (CMs) and scoliosis has been growing over the last three decades; yet, no consensus on the optimal management approach in this patient population has been reached. Spinal anomalies such as isolated syrinxes, isolated CM, and CM with a syrinx are relatively common among patients with presumed idiopathic scoliosis (IS), a rule that also applies to scoliosis among CM patients as well. In CM patients, scoliosis presents with atypical features such as early onset, left apical or kyphotic curvature, and neurological deficits. While spinal X-rays are essential to confirm the diagnosis of scoliosis among CM patients, a magnetic resonance imaging (MRI) is also recommended in IS patients with atypical presentations. Hypotheses attempting to explain the occurrence of scoliosis in CM patients include cerebellar tonsillar compression of the cervicomedullary junction and uneven expansion of a syrinx in the horizontal plane of the spinal cord. Early detection of scoliosis on routine spinal examination and close follow-up on curve stability and progression are essential initial steps in the management of scoliosis, especially in patients with CM, who may require full spine MRI to screen for associated neuro-axial anomalies; bracing and spinal fusion may be subsequently pursued in high-risk patients.

Management of hydrocephalus and subdural hygromas in pediatric patients after decompression of Chiari malformation type I: case series and review of the literature

OBJECTIVE

Hydrocephalus associated with subdural hygromas is a rare complication after decompression of Chiari malformation type I (CM-I). There is no consensus for management of this complication. The authors present a series of 5 pediatric patients who underwent CM-I decompression with placement of a dural graft complicated by posterior fossa hygromas and hydrocephalus that were successfully managed nonoperatively.

METHODS

A retrospective review over the last 5 years of patients who presented with hydrocephalus and subdural hygromas following foramen magnum decompression with placement of a dural graft for CM-I was conducted at 2 pediatric institutions. Their preoperative presentation, perioperative hospital course, and postoperative re-presentation are discussed with attention to their treatment regimen and ultimate outcome. In addition to reporting these cases, the authors discuss all similar cases found in their literature review.

RESULTS

Over the last 5 years, the authors have encountered 194 pediatric cases of CM-I decompression with duraplasty equally distributed at the 2 institutions. Of those cases, 5 pediatric patients with a delayed postoperative complication involving hydrocephalus and subdural hygromas were identified. The 5 patients were managed nonoperatively with acetazolamide and high-dose dexamethasone; dosages of both drugs were adjusted to the age and weight of each patient. All patients were symptom free at follow-up and exhibited resolution of their pathology on imaging. Thirteen similar pediatric cases and 17 adult cases were identified in the literature review. Most reported cases were treated with CSF diversion or reoperation. There were a total of 4 cases previously reported with successful nonoperative management. Of these cases, only 1 case was reported in the pediatric population.

CONCLUSIONS

De novo hydrocephalus, in association with subdural hygromas following CM-I decompression, is rare. This presentation suggests that these complications after posterior fossa decompression with duraplasty can be treated with nonoperative medical management, therefore obviating the need for CSF diversion or reoperation.

Population-based Study Determining Predictors of Cancer-Specific Mortality and Survival in Pediatric High-grade Brainstem Glioma

BACKGROUND

Pediatric high-grade brainstem gliomas are aggressive tumors with dismal prognoses. Large-scale studies are needed to further characterize these tumors and determine factors influencing cancer-specific mortality and survival at varying time points.

METHODS

We used the SEER (Surveillance Epidemiology and End Results) database to conduct a population-based study of pediatric patients with histologically confirmed anaplastic astrocytoma or glioblastoma tumors located within the brainstem. Multivariate analyses incorporating patient demographics, tumor characteristics, and treatments were used to determine predictors of cancer-specific mortality and survival at 6 months, 9 months, 1 year, and 2 years.

RESULTS

We included 154 patients from the SEER database: 72 patients with anaplastic astrocytoma (47%) and 82 (53%) with glioblastoma. Median survival for the entire cohort was 10.0 months. Glioblastoma histology, developmental stage, and large tumor size were significantly associated with cancer-specific mortality. Six-month, 9-month, 1-year, and 2-year survival was 75%, 57%, 42%, and 20%, respectively. Glioblastoma histology was associated with worsened survival at 6 months (odds ratio [OR], 0.19; P = 0.0081), 9 months (OR, 0.18; P < 0.001), 1 year (OR, 0.19; P < 0.001), and 2 years (OR, 0.14; P = 0.0055). Radiation therapy was associated with improved survival at 6 (OR, 8.53; P = 0.0012) and 9 months (OR, 3.58; P = 0.035) but not at 1 or 2 years. Radiation therapy was associated with improved survival in glioblastoma (9.0 vs. 3.0 months; P < 0.001).

CONCLUSIONS

This population-based study showed that glioblastoma histology is associated with a poor prognosis in pediatric patients with high-grade brainstem gliomas. Regardless of histology, radiation therapy improved survival at 6 and 9 months but not long-term.

Instrumented fusion for spinal deformity after laminectomy or laminoplasty for resection of intramedullary spinal cord tumors in pediatric patients

OBJECTIVE Spinal deformity has become a well-recognized complication of intramedullary spinal cord tumor (IMSCT) resection. In particular, laminectomy can result in biomechanical instability caused by loss of the posterior tension band. Therefore, laminoplasty has been proposed as an alternative to laminectomy. Here, the authors describe the largest current series of pediatric patients who have undergone laminoplasty for IMSCT resection and investigate the need for surgical fusion after both laminectomy and laminoplasty. METHODS The medical records of pediatric patients who underwent resection of an IMSCT at a single institution between November 2003 and May 2014 were reviewed retrospectively. Demographic, clinical, radiological, surgical, histopathological, and follow-up data were collected. RESULTS Sixty-six consecutive patients underwent resection of an IMSCT during the study period. Forty-three (65%) patients were male. The patients had a median age of 12.9 years (interquartile range [IQR] 7.2-16.5 years) at the time of surgery. Patients typically presented with a tumor that involved the cervical and/or thoracic spine. Nineteen (29%) patients underwent laminectomy, and 47 (71%) patients underwent laminoplasty. Patients in each cohort had a similar rate of postoperative deformity. Overall, 10 (15%) patients required instrumented spinal fusion for spinal deformity. Four patients required revision of the primary fusion. CONCLUSIONS These findings show that among pediatric patients with an IMSCT, postoperative surgical fusion rates remain high, even after laminoplasty. Known risk factors, such as the age of the patient, location of the tumor, and the number of involved levels, might play a larger role than replacement of the laminae in determining the rate of surgical fusion after IMSCT resection.

Pediatric cerebral venous sinus thrombosis or compression in the setting of skull fractures from blunt head trauma

OBJECTIVE Pediatric cerebral venous sinus thrombosis has been previously described in the setting of blunt head trauma; however, the population demographics, risk factors for thrombosis, and the risks and benefits of detection and treatment in this patient population are poorly defined. Furthermore, few reports differentiate between different forms of sinus pathology. A series of pediatric patients with skull fractures who underwent venous imaging and were diagnosed with intrinsic cerebral venous sinus thrombosis or extrinsic sinus compression is presented. METHODS The medical records of patients at 2 pediatric trauma centers were retrospectively reviewed. Patients who were evaluated for blunt head trauma from January 2003 to December 2013, diagnosed with a skull fracture, and underwent venous imaging were included. RESULTS Of 2224 pediatric patients with skull fractures following blunt trauma, 41 patients (2%) underwent venous imaging. Of these, 8 patients (20%) had intrinsic sinus thrombosis and 14 patients (34%) displayed extrinsic compression of a venous sinus. Three patients with intrinsic sinus thrombosis developed venous infarcts, and 2 of these patients were treated with anticoagulation. One patient with extrinsic sinus compression by a depressed skull fracture underwent surgical elevation of the fracture. All patients with sinus pathology were discharged to home or inpatient rehabilitation. Among patients who underwent follow-up imaging, the sinus pathology had resolved by 6 months postinjury in 80% of patients with intrinsic thrombosis as well as 80% of patients with extrinsic compression. All patients with intrinsic thrombosis or extrinsic compression had a Glasgow Outcome Scale score of 4 or 5 at their last follow-up. CONCLUSIONS In this series of pediatric trauma patients who underwent venous imaging for suspected thrombosis, the yield of detecting intrinsic thrombosis and/or extrinsic compression of a venous sinus was high. However, few patients developed venous hypertension or infarction and were subsequently treated with anticoagulation or surgical decompression of the sinus. Most had spontaneous resolution and good neurological outcomes without treatment. Therefore, in the setting of pediatric skull fractures after blunt injury, venous imaging is recommended when venous hypertension or infarction is suspected and anticoagulation is being considered. However, there is little indication for pervasive venous imaging after pediatric skull fractures, especially in light of the potential risks of CT venography or MR venography in the pediatric population and the unclear benefits of anticoagulation.

Chiari 1 deformity in children: etiopathogenesis and radiologic diagnosis

The metamerically associated normal hindbrain and normal posterior fossa are programmed to grow together in such a way that the tonsils are located above the foramen magnum and surrounded by the cerebrospinal fluid (CSF) of the cisterna magna. This allows the pulsating CSF to move freely up and down across the craniovertebral junction (CVJ). A developmental mismatch between the rates of growth of the neural tissue and of the bony posterior fossa may result in the cerebellar tonsils being dislocated across the foramen magnum. The cause of this may be, rarely, an overgrowth of the cerebellum. More commonly, it is due to an insufficient development of the posterior fossa, possibly associated with a malformation of the craniocervical joint. When it is not due to a remediable cause, such a herniation is called a Chiari 1 deformity. This definition is anatomic (descent of the tonsils below the plane of the foramen magnum) and not clinical: many patients with the deformity are and will remain asymptomatic. Most authors consider that a descent of 5 mm or more is clinically significant but other factors, such as the diameter of the foramen magnum and the degree of tapering of the upper cervical "funnel," are likely to be as important. Morphologic markers of severity on magnetic resonance imaging are, beside the degree of descent, the peg-like deformity of the tonsils, the obstruction of the surrounding CSF spaces (at the craniocervical junction and in the whole posterior fossa), a compression of the cord, an abnormal signal of the cord, and a syringomyelia, typically cervicothoracic. The syringomyelia is assumed to be explained by the "Venturi effect" that is associated with the increased velocity of the CSF across the restricted CSF spaces. Radiologically, the etiopathogenic assessment should address the size and morphology of the posterior fossa, and the functional status of the craniocervical flexion joint. The posterior fossa is best evaluated on sagittal cuts by the posterior fossa pentagon proportionality associated with the line of Chamberlain, and on coronal cuts, by showing a possible shallowness of the posterior fossa. The functional status of the craniocervical joint is altered in case of a proatlantal hypoplasia, as this condition results in a cranial shift of the joint that brings the tip of the dens and of the flexion axis in front of the medulla, that is, in a situation of osteoneural conflict. Less commonly, similar conflicts may also occur when an abnormal craniocervical segmentation results in an instability of the joint.

Use of computer-assisted design and manufacturing to localize dural venous sinuses during reconstructive surgery for craniosynostosis

OBJECTIVE

Cranial vault remodeling surgery for craniosynostosis carries the potential risk of dural venous sinus injury given the extensive bony exposure. Identification of the dural venous sinuses can be challenging in patients with craniosynostosis given the lack of accurate surface-localizing landmarks. Computer-aided design and manufacturing (CAD/CAM) has allowed surgeons to pre-operatively plan these complex procedures in an effort to increase reconstructive efficiency. An added benefit of this technology is the ability to intraoperatively map the dural venous sinuses based on pre-operative imaging. We utilized CAD/CAM technology to intraoperatively map the dural venous sinuses for patients undergoing reconstructive surgery for craniosynostosis in an effort to prevent sinus injury, increase operative efficiency, and enhance patient safety. Here, we describe our experience utilizing this intraoperative technology in pediatric patients with craniosynostosis.

METHODS

We retrospectively reviewed the charts of children undergoing reconstructive surgery for craniosynostosis using CAD/CAM surgical planning guides at our institution between 2012 and 2016. Data collected included the following: age, gender, type of craniosynostosis, estimated blood loss, sagittal sinus deviation from the sagittal suture, peri-operative outcomes, and hospital length of stay.

RESULTS

Thirty-two patients underwent reconstructive cranial surgery for craniosynostosis, with a median age of 11 months (range, 7-160). Types of synostosis included metopic (6), unicoronal (6), sagittal (15), lambdoid (1), and multiple suture (4). Sagittal sinus deviation from the sagittal suture was maximal in unicoronal synostosis patients (10.2 ± 0.9 mm). All patients tolerated surgery well, and there were no occurrences of sagittal sinus, transverse sinus, or torcular injury.

CONCLUSIONS

The use of CAD/CAM technology allows for accurate intraoperative dural venous sinus localization during reconstructive surgery for craniosynostosis and enhances operative efficiency and surgeon confidence while minimizing the risk of patient morbidity.

Primary intramedullary spinal cord lymphoma: a population-based study

Background

Primary intramedullary spinal cord lymphoma (PISCL) is a rare diagnosis with poorly understood disease progression. Clarification of the factors associated with survival in PISCL patients is warranted.

Methods

We conducted a population-based cohort study utilizing prospectively collected data from the Surveillance, Epidemiology, and End Results (SEER) database. Patients with histological diagnosis of primary lymphoma in spinal cord (C72.0) from 1973 to 2012 in the SEER database were included. Multivariable survival analysis between patient, lesion characteristics, and PISCL-related death was performed to adjust for confounding factors.

Results

We included 346 PISCL patients in our study. Average age was 56.5 ± 17.8 years, with 62.7% being male. Racial distribution of these patients was white (87.6%), black (8.0%), and other (4.3%). More than half (55.8%) of patients were married. The most prevalent histology of PISCL was diffuse B-cell (46.2%), and the majority (55.2%) were low stage (Ann Arbor stage I/II). Most patients (67.9%) received radiation therapy. Average survival interval of patients with PISCL-related death (n=135, 39.0%) was 27.8 months. General cumulative survival probability at 1 year, 2 years, and 5 years was 73.8%, 67.9%, and 63.1%, respectively. Multivariable accelerated failure time (AFT) regression showed follicular lymphoma (HR:0.25, P=.008) and more recent diagnosis (HR:0.96, P<.001) was positively associated with PISCL-related survival. Conversely, nonwhite race (HR:1.69, P=.046), older age (HR:1.02, P<.001), unmarried status (HR:2.14, P<.001), and higher stage (HR:1.54, P=.022) were negatively associated with survival.

Conclusions

Age, race, marital status, tumor histology, tumor stage, and year of diagnosis were associated with survival of PISCL. While most PISCL-related deaths occur within a 1-year period, subsequent slow progression was observed after the first year of survival.

Pediatric spinal cord astrocytomas: a retrospective study of 348 patients from the SEER database

OBJECTIVE Intramedullary spinal cord tumors comprise 1%-10% of all childhood central nervous system neoplasms, with astrocytomas representing the most common subtype. Due to their rarity and poor prognosis, large population-based studies are needed to assess the epidemiology and survival risk factors associated with these tumors in the hope of improving outcome. The authors undertook this retrospective study to explore factors that may influence survival in pediatric patients with spinal cord astrocytomas. METHODS Utilizing the Surveillance, Epidemiology, and End Results (SEER) database, a prospective cancer registry, the authors retrospectively assessed survival in histologically confirmed, primary spinal cord astrocytomas in patients 21 years of age and younger. Survival was described with Kaplan-Meyer curves, and a multivariate regression analysis was used to assess the association of several variables with survival while controlling for confounding variables. RESULTS This analysis of 348 cases showed that age (hazard ratio [HR] 1.05, 95% CI 1.01-1.09, p = 0.017), nonwhite race (HR 1.74, 95% CI 1.11-2.74, p = 0.014), high-grade tumor status (HR 14.67, 95% CI 6.69-32.14, p < 0.001), distant or invasive extension of the tumor (HR 2.37, 95% CI 1.02-5.49, p = 0.046), and radiation therapy (HR 3.74, 95% CI 2.18-6.41, p < 0.001) were associated with decreased survival. Partial resection (HR 0.37, 95% CI 0.16-0.83, p = 0.017) and gross-total resection (HR 0.39, 95% CI 0.16-0.95, p = 0.039) were associated with improved survival. CONCLUSIONS Younger age appears to be protective, while high-grade tumors have a much worse prognosis. Early diagnosis and access to surgery appears necessary for improving outcomes, while radiation therapy has an unclear role. There is still much to learn about this disease in the hope of curing children with the misfortune of having one of these rare tumors.

Ototoxicity of Carboplatin Delivered Locally in a Monkey Brainstem

Ototoxicity is a common side effect of platinum-based chemotherapy. Intratumoral drug delivery theoretically could reduce the ototoxic effects of systemic drug infusions. However, local delivery to central nervous system (CNS) tumors might promote ototoxicity through drug release into cerebrospinal fluid (CSF). This report describes an examination of the cytoarchitecture of vestibular cells of cynomolgus monkeys that had chronic brainstem infusions with the maximum tolerated dose (MTD) of carboplatin. The brainstems of adult monkeys were infused for 30 days at 0.42 μl/h with 0.025 to 0.25 mg/kg (MTD) of carboplatin. The vestibular sensory epithelia of eight drug-treated animals were isolated for microscopic examination of vestibular hair cells and support cells. Local infusions produced chronic elevated CSF levels of platinum, neurological symptoms, and radiographic evidence of pontine injury. Histology revealed significant cell damage at the infusion sites. Microscopic examinations of vestibular support cells and hair cells demonstrate a small reduction in cell counts in the drug-treated monkeys compared to a noninfused control animal. Parametric and nonparametric tests show no effect of dose in predicting the vestibular cell counts. In this single study of eight monkeys, a dose-dependent reduction of vestibular hair cells or support cells was not observed in animals infused with brainstem infusions of 0.025 to 0.25 mg/kg of carboplatin.

Timing of cranial vault remodeling in nonsyndromic craniosynostosis: a single-institution 30-year experience

OBJECTIVE Due to the changing properties of the infant skull, there is still no clear consensus on the ideal time to surgically intervene in cases of nonsyndromic craniosynostosis (NSC). This study aims to shed light on how patient age at the time of surgery may affect surgical outcomes and the subsequent need for reoperation. METHODS A retrospective cohort review was conducted for patients with NSC who underwent primary cranial vault remodeling between 1990 and 2013. Patients' demographic and clinical characteristics and surgical interventions were recorded. Postoperative outcomes were assessed by assigning each procedure to a Whitaker category. Multivariate logistic regression analysis was performed to determine the relationship between age at surgery and need for minor (Whitaker I or II) versus major (Whitaker III or IV) reoperation. Odds ratios (ORs) for Whitaker category by age at surgery were assigned. RESULTS A total of 413 unique patients underwent cranial vault remodeling procedures for NSC during the study period. Multivariate logistic regression demonstrated increased odds of requiring major surgical revisions (Whitaker III or IV) in patients younger than 6 months of age (OR 2.49, 95% CI 1.05-5.93), and increased odds of requiring minimal surgical revisions (Whitaker I or II) in patients older than 6 months of age (OR 2.72, 95% CI 1.16-6.41). CONCLUSIONS Timing, as a proxy for the changing properties of the infant skull, is an important factor to consider when planning vault reconstruction in NSC. The data presented in this study demonstrate that patients operated on before 6 months of age had increased odds of requiring major surgical revisions.

Chiari Type 1 Deformity in Children: Pathogenetic, Clinical, Neuroimaging, and Management Aspects

Our understanding of cerebellar tonsillar herniation evolved over time and nowadays various pathomechanisms have been proposed. Causes of tonsillar herniation share a discrepancy between content (fore- and hindbrain) and container (supratentorial cranial vault, posterior fossa), may be associated with abnormalities of the craniocervical junction, and may have a developmental or acquired nature. In tonsillar herniation, the hindbrain is not malformed but deformed. Accordingly, "Chiari type 1 deformity," not "Chiari type 1 malformation" is the correct term to characterize primary tonsillar herniation. Chiari type 1 deformity is commonly seen in pediatric neurology, neuroradiology, and neurosurgery and may have various clinical presentations depending on patient age. In addition, Chiari type 1 deformity is increasingly found by neuroimaging studies as an incidental finding in asymptomatic children. An accurate and reliable selection of patients based on clinical and neuroimaging findings is paramount for the success of neurosurgical treatment. Future studies are needed to provide selection criteria with a higher sensitivity and specificity.

Management of pediatric intracranial low-grade gliomas: long-term follow-up after radiation therapy

INTRODUCTION

The treatment of pediatric intracranial low-grade gliomas (LGG) generally begins with maximal safe resection. Radiation therapy (RT) and chemotherapy are typically reserved for patients with incomplete resection and/or disease progression. We report long-term treatment outcomes and toxicities in a cohort of pediatric patients with LGG after RT.

METHODS

Thirty-four patients <21 years old with intracranial LGG who were treated with RT at the Johns Hopkins Hospital were included in this retrospective analysis. Patients were evaluated for overall survival (OS), progression-free survival (PFS), recurrence patterns, and treatment toxicities using descriptive statistics, Kaplan-Meier curves, and Cox proportional hazard regressions.

RESULTS

The mean age at diagnosis was 7.9 years (range 1.2-18.3 years) and mean age at RT was 9.8 years (range 3.0-28.9 years). The median follow-up time was 9.8 years after radiation (range 0.8-33.3 years). The estimated 10-year OS and PFS after RT were 92 and 74 %, respectively. Twelve patients had disease progression after RT, and all recurrences were local. Two patients died due to disease progression 2.3 and 9.1 years after RT. One patient had malignant transformation of LGG to high-grade glioma. No significant predictors of PFS were identified on uni- or multivariate analysis. Late effects of LGG and treatment seen were endocrine deficiencies in 16 patients, visual problems in 10 patients, hearing loss in 4 patients, special education requirements for 5 patients, and a vascular injury/demyelination secondary to RT in 1 patient.

CONCLUSION

Our study suggests that the use of radiation in patients with intracranial LGG results in excellent OS and PFS with acceptable toxicity at long-term follow-up.

Surgical Management of Osteoblastoma of the Spine: Case Series and Review of the Literature

AIM

To describe the demographics, clinical and radiologic presentation, surgical considerations, and clinical outcomes associated with spinal osteoblastoma.

MATERIAL AND METHODS

A spinal tumor database of 522 patients treated surgically at a single institution between January 2002 and June 2012 was analyzed and five patients with spinal osteoblastoma were identified and included in this study. Basic demographic and epidemiological data were recorded. Tumor characteristics, surgical parameters, and clinical follow-up data were noted.

RESULTS

The mean follow-up was 21.9 months. There were four males and one female, and the mean age at diagnosis was 28.4 years. There was a mean reported symptom length of 26.4 months prior to diagnosis. There were three cervical lesions, one lumbar lesion, and one sacrococcygeal lesion. One patient was Enneking stage III and four patients were Enneking stage II. Based on spinal instability neoplastic score criteria, two patients were stable and three patients were potentially unstable. Four patients had intralesional gross total resections and one patient had an en bloc marginal resection. All patients remained neurologically stable or improved postoperatively. A single patient had recurrence of a previously resected osteoid osteoma with progression to osteoblastoma.

CONCLUSION

Aggressive surgical resection of spinal osteoblastoma is suggested to minimize the risk of tumor recurrence, although this may still occur even with en bloc resection. Patients rarely present with preoperative spinal instability, but surgical fusion is often required due to removal of structural elements of the spine during resection. Of note, osteoid osteoma may progress to osteoblastoma in the spine despite prior resection.

Intraoperative spinal digital subtraction angiography: indications, technique, safety, and clinical impact

Background

Cerebral intraoperative DSA (IODSA) is a well-described, routinely performed procedure that allows the effectiveness of cerebrovascular interventions to be evaluated in the operating room. Spinal IODSA, on the other hand, is infrequently obtained and has received less attention.

Objective

To discuss the indications, technique, safety, and clinical impact of spinal IODSA.

Materials and methods

Twenty-three patients underwent 45 thoracic and/or lumbar spinal IODSA between 2005 and 2016, either immediately before surgery for lesion localization or after the intervention to evaluate its effectiveness. Indications included 21 vascular malformations and 2 diaphragmatic crus compression syndromes. A long femoral arterial sheath with its hub positioned on the lateral surface of the thigh was used to allow catheter manipulations in the prone position.

Results

All targeted intersegmental arteries (ISAs) were successfully catheterized. The course of surgery was changed in 6 instances (26.1%). In 4 cases of epidural or perimedullary arteriovenous fistulae (AVFs), a residual lesion required additional intervention. In one case of epidural AVF, initial IODSA revealed spontaneous resolution of the lesion, preventing unnecessary surgery. Finally, angiography performed in a case of diaphragmatic crus syndrome showed thrombosis of the ISA and non-visualization of the artery of Adamkiewicz. Recanalization was obtained by IA thrombolysis, with excellent clinical outcome. No intraprocedural or postprocedural complication was noted.

Conclusions

Spinal IODSA is a safe technique that offers an immediate assessment of the effectiveness of a spinovascular surgical procedure, notably epidural and perimedullary AVFs. Spinal IODSA was technically successful in all cases, influencing the surgical strategy in 6 of 23 patients, including one patient who benefited from intraoperative endovascular therapy.