Indications for cerebral revascularization for moyamoya syndrome in pediatric sickle cell disease determined by Delphi methodology.

OBJECTIVE: Cerebral revascularization surgery (CRS) has been used to prevent stroke in children with sickle cell disease (SCD) and cerebral vasculopathy (e.g., moyamoya syndrome). While results suggest that it may be an effective treatment, surgical indications have not been well defined. This study sought to determine indications for offering revascularization surgery in centers with established sickle cell programs in the US. METHODS: Three sequential surveys utilizing the Delphi methodology were administered to neurosurgeons participating in the Stroke in Sickle Cell Revascularization Surgery study. Respondents were presented with clinical scenarios of patients with SCD and varying degrees of ischemic presentation and vasculopathy, and the group's agreement to offer surgical revascularization was measured. Consensus was defined as ≥ 75% similar responses. RESULTS: The response rate to all 3 surveys was 100%. Seventeen neurosurgeons from 16 different centers participated. The presence of moyamoya collaterals (MMCs) and arterial stenosis matching an ischemic distribution yielded the strongest recommendations to offer surgery. There was consensus to offer revascularization in the presence of MMCs and at least 50% arterial stenosis matching an ischemic distribution. In contrast, there was no consensus to offer revascularization with 50%-70% stenosis not matching an ischemic presentation in the absence of MMCs. The presence of the ivy sign in the distribution of the stenotic artery also contributed to the consensus to offer surgery in certain scenarios. CONCLUSIONS: There were several clinical scenarios that attained consensus to offer surgery; the strongest was moderate to severe arterial stenosis that matched the distribution of ischemic presentation in the presence of MMCs. Radiological findings of decreased cerebral flow or perfusion also facilitated attaining consensus to offer surgery. The findings of this study reflect expert opinion about questions that deserve prospective clinical research. Determination of indications for CRS can guide clinical practice and aid the design of prospective studies.

Modeling blood-brain barrier formation and cerebral cavernous malformations in human PSC-derived organoids.

The human blood-brain barrier (hBBB) is a highly specialized structure that regulates passage across blood and central nervous system (CNS) compartments. Despite its critical physiological role, there are no reliable in vitro models that can mimic hBBB development and function. Here, we constructed hBBB assembloids from brain and blood vessel organoids derived from human pluripotent stem cells. We validated the acquisition of blood-brain barrier (BBB)-specific molecular, cellular, transcriptomic, and functional characteristics and uncovered an extensive neuro-vascular crosstalk with a spatial pattern within hBBB assembloids. When we used patient-derived hBBB assembloids to model cerebral cavernous malformations (CCMs), we found that these assembloids recapitulated the cavernoma anatomy and BBB breakdown observed in patients. Upon comparison of phenotypes and transcriptome between patient-derived hBBB assembloids and primary human cavernoma tissues, we uncovered CCM-related molecular and cellular alterations. Taken together, we report hBBB assembloids that mimic the core properties of the hBBB and identify a potentially underlying cause of CCMs.

Pediatric Moyamoya Revascularization Perioperative Care: A Modified Delphi Study.

BACKGROUND: Surgical revascularization decreases the long-term risk of stroke in children with moyamoya arteriopathy but can be associated with an increased risk of stroke during the perioperative period. Evidence-based approaches to optimize perioperative management are limited and practice varies widely. Using a modified Delphi process, we sought to establish expert consensus on key components of the perioperative care of children with moyamoya undergoing indirect revascularization surgery and identify areas of equipoise to define future research priorities. METHODS: Thirty neurologists, neurosurgeons, and intensivists practicing in North America with expertise in the management of pediatric moyamoya were invited to participate in a three-round, modified Delphi process consisting of a 138-item practice patterns survey, anonymous electronic evaluation of 88 consensus statements on a 5-point Likert scale, and a virtual group meeting during which statements were discussed, revised, and reassessed. Consensus was defined as ≥ 80% agreement or disagreement. RESULTS: Thirty-nine statements regarding perioperative pediatric moyamoya care for indirect revascularization surgery reached consensus. Salient areas of consensus included the following: (1) children at a high risk for stroke and those with sickle cell disease should be preadmitted prior to indirect revascularization; (2) intravenous isotonic fluids should be administered in all patients for at least 4 h before and 24 h after surgery; (3) aspirin should not be discontinued in the immediate preoperative and postoperative periods; (4) arterial lines for blood pressure monitoring should be continued for at least 24 h after surgery and until active interventions to achieve blood pressure goals are not needed; (5) postoperative care should include hourly vital signs for at least 24 h, hourly neurologic assessments for at least 12 h, adequate pain control, maintaining normoxia and normothermia, and avoiding hypotension; and (6) intravenous fluid bolus administration should be considered the first-line intervention for new focal neurologic deficits following indirect revascularization surgery. CONCLUSIONS: In the absence of data supporting specific care practices before and after indirect revascularization surgery in children with moyamoya, this Delphi process defined areas of consensus among neurosurgeons, neurologists, and intensivists with moyamoya expertise. Research priorities identified include determining the role of continuous electroencephalography in postoperative moyamoya care, optimal perioperative blood pressure and hemoglobin targets, and the role of supplemental oxygen for treatment of suspected postoperative ischemia.

Cerebral revascularization surgery reduces cerebrovascular events in children with sickle cell disease and moyamoya syndrome: Results of the stroke in sickle cell revascularization surgery retrospective study.

BACKGROUND: Recent studies suggest that cerebral revascularization surgery may be a safe and effective therapy to reduce stroke risk in patients with sickle cell disease and moyamoya syndrome (SCD-MMS). METHODS: We performed a multicenter, retrospective study of children with SCD-MMS treated with conservative management alone (conservative group)-chronic blood transfusion and/or hydroxyurea-versus conservative management plus surgical revascularization (surgery group). We monitored cerebrovascular event (CVE) rates-a composite of strokes and transient ischemic attacks. Multivariable logistic regression was used to compare CVE occurrence and multivariable Poisson regression was used to compare incidence rates between groups. Covariates in multivariable models included age at treatment start, age at moyamoya diagnosis, antiplatelet use, CVE history, and the risk period length. RESULTS: We identified 141 patients with SCD-MMS, 78 (55.3%) in the surgery group and 63 (44.7%) in the conservative group. Compared with the conservative group, preoperatively the surgery group had a younger age at moyamoya diagnosis, worse baseline modified Rankin scale scores, and increased prevalence of CVEs. Despite more severe pretreatment disease, the surgery group had reduced odds of new CVEs after surgery (odds ratio = 0.27, 95% confidence interval [CI] = 0.08-0.94, p = .040). Furthermore, comparing surgery group patients during presurgical versus postsurgical periods, CVEs odds were significantly reduced after surgery (odds ratio = 0.22, 95% CI = 0.08-0.58, p = .002). CONCLUSIONS: When added to conservative management, cerebral revascularization surgery appears to reduce the risk of CVEs in patients with SCD-MMS. A prospective study will be needed to validate these findings.

Ocular survival after intra-arterial chemotherapy for retinoblastoma improves with accrual of experience and programmatic evolution.

BACKGROUND: Intra-arterial chemotherapy (IAC) for the treatment of intraocular retinoblastoma has gained recognition as a method to improve ocular salvage; however, there is a paucity of evidence supporting treatment factors prognosticating ocular survival. METHODS: All patients with retinoblastoma treated with IAC at a single institution between December 2008 and December 2019 were evaluated. Patient demographics, tumor classification, prior treatments, procedural data, other non-IAC therapies, adverse reactions, procedural complications, ocular outcomes, and overall survival were assessed via retrospective chart review. Factors suggestive of increased ocular survival were identified via univariate and multivariate analyses. The impact of accrued treatment experience was evaluated by grouping eyes by the respective year, IAC treatment was initiated. RESULTS: Forty-nine eyes of 43 patients were treated for retinoblastoma with IAC (256 total procedures). At least grade 3 neutropenia was observed following 19% of IAC procedures. The risk of neutropenia was not statistically different between single or multidrug IAC. Comparing those who received balloon-assisted intra-arterial chemotherapy (bIAC) in more than two-thirds of cycles to those who did not, the risk of arterial access site complications was not statistically different. Multivariate analysis revealed a significantly lower risk of enucleation associated with treatment era in years (hazard ratio [HR] = 0.52-1.00, p < .05) and laser therapies (HR = 0.02-0.60, p < .05). CONCLUSIONS: Ocular survival rates in patients treated with IAC for retinoblastoma at our institution have increased over time. Accrued treatment experience and programmatic changes have likely contributed. Larger, prospective series may lead to a better understanding of factors that consistently contribute to better ocular salvage.

Fetal and postnatal MRI findings of Blake pouch remnant causing obstructive hydrocephalus.

Blake pouch remnant, also known as Blake pouch cyst or persistent Blake pouch, is a posterior fossa embryologic anomaly that is often seen in isolation with most affected patients being asymptomatic. However, even in isolation, Blake pouch remnant can result in obstructive hydrocephalus requiring early neurosurgical intervention making it an important diagnosis for the fetal radiologist to consider. We present a rare case of a patient with prenatally diagnosed "inferior vermian hypoplasia" on fetal MRI that went on to develop progressive obstructive hydrocephalus in infancy secondary to what was determined to be a Blake pouch remnant.

Cancer and Tumor-Associated Childhood Stroke: Results From the International Pediatric Stroke Study.

BACKGROUND: The prevalence of cancer among children with stroke is unknown. This study sought to evaluate cancer- and tumor-associated childhood ischemic stroke in a multinational pediatric stroke registry. METHODS: Children aged 29 days to less than 19 years with arterial ischemic stroke or cerebral sinovenous thrombosis enrolled in the International Pediatric Stroke Study between January 2003 and June 2019 were included. Data including stroke treatment and recurrence were compared between subjects with and without cancer using Wilcoxon rank sum and chi-square tests. RESULTS: Cancer or tumor was present in 99 of 2968 children (3.3%) with arterial ischemic stroke and 64 of 596 children (10.7%) with cerebral sinovenous thrombosis. Among children in whom cancer type was identified, 42 of 88 arterial ischemic stroke cases (48%) had brain tumors and 35 (40%) had hematologic malignancies; 45 of 58 cerebral sinovenous thrombosis cases (78%) had hematologic malignancies and eight (14%) had brain tumors. Of 54 cancer-associated arterial ischemic stroke cases with a known cause, 34 (63%) were due to arteriopathy and nine (17%) were due to cardioembolism. Of 46 cancer-associated cerebral sinovenous thrombosis cases with a known cause, 41 (89%) were related to chemotherapy-induced or other prothrombotic states. Children with cancer were less likely than children without cancer to receive antithrombotic therapy for arterial ischemic stroke (58% vs 80%, P = 0.007) and anticoagulation for cerebral sinovenous thrombosis (71% vs 87%, P = 0.046). Recurrent arterial ischemic stroke (5% vs 2%, P = 0.04) and cerebral sinovenous thrombosis (5% vs 1%, P = 0.006) were more common among children with cancer. CONCLUSIONS: Cancer is an important risk factor for incident and recurrent childhood stroke. Stroke prevention strategies for children with cancer are needed.

Spectrum of cerebral arterial and venous abnormalities in Alagille syndrome.

BACKGROUND: Alagille syndrome is a pediatric multisystem disease with increased prevalence of cerebrovascular disease. The spectrum of cerebrovascular disease in Alagille syndrome includes cerebral aneurysms, moyamoya arteriopathy and dolichoectasia. The prevalence of cerebrovascular disease in Alagille syndrome varies widely in the literature. OBJECTIVE: To determine the prevalence of cerebrovascular disease in our institution's Alagille patient population by employing a full primary review of all available neuroimaging. MATERIALS AND METHODS: An institutional review board-approved retrospective review of all Alagille syndrome patients seen at a tertiary care children's hospital from January 2000 to January 2014 was performed. All neuroimaging studies were reviewed for arterial or venous abnormalities. The prevalence of arterial and venous abnormalities was calculated and clinical outcomes were determined. RESULTS: Fifty-two patients with Alagille syndrome ranging in age from 11 months to 27 years were studied. Nineteen (37%) had dedicated vascular neuroimaging. Six (32%) had cerebral arterial disease, 4 with dolichoectasia, 3 with aneurysm(s) and 2 with moyamoya arteriopathy. Three of the four patients with dolichoectasia had associated aneurysm(s). Venous anomalies were present in 4 (21%) patients. One patient with moyamoya arteriopathy underwent revascularization procedures. No deaths were attributable to cerebrovascular disease. CONCLUSION: Cerebral vasculopathy is an important feature of Alagille syndrome and includes dolichoectasia, cerebral aneurysms and moyamoya arteriopathy. The high prevalence identified in our study suggests noninvasive vascular neuroimaging screening should be performed in this patient population. In addition to cerebral arterial abnormalities, alterations of venous development may be a feature of Alagille syndrome.

Chiari I malformation in children with transverse myelitis.

PURPOSE: Transverse myelitis (TM) is an acute inflammatory spinal cord injury. Asymptomatic Chiari I malformation (CMI) management is highly controversial, particularly when associated with a spinal syrinx. Here, we assess the occurrence of CMI in the pediatric TM population and management outcomes. METHODS: We performed a retrospective cohort study based on 61 consecutively identified pediatric TM cases over an -8-year period. We reviewed demographic characteristics, radiographic findings, presenting symptoms, and long-term outcomes. RESULTS: Eight CMI cases were identified within the TM cohort; all presented with TM by 16 months of age and affecting the cervical spinal cord. In three cases, CMI developed 15 months to 6 years after the onset of TM. One in 10 children with TM had CMI. CONCLUSION: These findings demonstrate a high prevalence of CMI in patients with TM. Large prospective clinical studies are needed to further investigate the natural history and recovery strategies of CMI involved with neuroinflammatory disorders.

High Frequency of Neuroimaging Abnormalities Among Pediatric Patients With Sepsis Who Undergo Neuroimaging.

OBJECTIVES: This study was intended to describe and correlate the neuroimaging findings in pediatric patients after sepsis. DESIGN: Retrospective chart review. SETTING: Single tertiary care PICU. PATIENTS: Patients admitted to Cincinnati Children's Hospital Medical Center with a discharge diagnosis of sepsis or septic shock between 2004 and 2013 were crossmatched with patients who underwent neuroimaging during the same time period. INTERVENTIONS: All neuroimaging studies that occurred during or subsequent to a septic event were reviewed, and all new imaging findings were recorded and classified. As many patients experienced multiple septic events and/or had multiple neuroimaging studies after sepsis, our statistical analysis utilized the most recent or "final" imaging study available for each patient so that only brain imaging findings that persisted were included. MEASUREMENTS AND MAIN RESULTS: A total of 389 children with sepsis and 1,705 concurrent or subsequent neuroimaging studies were included in the study. Median age at first septic event was 3.4 years (interquartile range, 0.7-11.5). Median time from first sepsis event to final neuroimaging was 157 days (interquartile range, 10-1,054). The most common indications for final imaging were follow-up (21%), altered mental status (18%), and fever/concern for infection (15%). Sixty-three percentage (n = 243) of final imaging studies demonstrated abnormal findings, the most common of which were volume loss (39%) and MRI signal and/or CT attenuation abnormalities (21%). On multivariable logistic regression, highest Pediatric Risk of Mortality score and presence of oncologic diagnosis/organ transplantation were independently associated with any abnormal final neuroimaging study findings (odds ratio, 1.032; p = 0.048 and odds ratio, 1.632; p = 0.041), although early timing of neuroimaging demonstrated a negative association (odds ratio, 0.606; p = 0.039). The most common abnormal finding of volume loss was independently associated with highest Pediatric Risk of Mortality score (odds ratio, 1.037; p = 0.016) and oncologic diagnosis/organ transplantation (odds ratio, 2.207; p = 0.001) and was negatively associated with early timing of neuroimaging (odds ratio, 0.575; p = 0.037). CONCLUSIONS: The majority of pediatric patients with sepsis and concurrent or subsequent neuroimaging have abnormal neuroimaging findings. The implications of this high incidence for long-term neurologic outcomes and follow-up require further exploration.

Neurosurgical laser ablation and MR thermometry: Risks of multisite workflow pattern.

Neurosurgical laser ablation is a relatively new but rapidly growing application of stereotactic neurosurgery that allows neurosurgeons to treat many previously untreatable conditions with the added benefit of shorter hospitalizations and recovery times. The vast majority of these procedures, however, are performed using a multisite workflow pattern involving transport of the patient between the operating room (OR), the computed tomography (CT) suite, and the magnetic resonance imaging (MRI) suite, often necessitating patient transfer through public pathways and requiring multiple trips if laser fiber placement is not accurate. There are significant risks posed to the patient with this practice and no existing guidelines addressing it. This article serves to identify those risks and present recommendations for safety optimization and risk reduction for those health care facilities using a multisite workflow pattern.

Angiographic Evidence of a Purely Pial Bihemispheric Intracranial Hemangiopericytoma.

Background. Classification of hemangiopericytoma (HPC) has evolved to a mesenchymal, nonmeningothelial grade two or three neoplasm according to the World Health Organization; however its blood supply has always been defined by dual origin, pial and dural contribution. Case Description. We present the case of a patient with an intracranial HPC with only pial vascular supply. Angiography confirmed the lack of dural supply to this bihemispheric intracranial mass. Subsequent histologic examination confirmed the diagnosis of hemangiopericytoma. Angiographic evidence here is atypical of the natural history of hemangiopericytomas with dual vascular supply and was critical in the decision-making towards surgical resection without tumor embolization. Conclusion. Data presented suggests the lack of dural vascular supply alone does not rule out the diagnosis of hemangiopericytoma.

Soft-tissue defects after spinal instrumentation in 5 children: risk factors, management strategies, and outcomes.

OBJECT: Wound-related complications following complex posterior spine procedures in children may result in the need for serial debridements and may place spinal instrumentation at risk. In this study, the authors review their experience with the management of soft-tissue defects from spinal instrumentation in 5 high-risk pediatric patients. The use of various rotational and transpositional flaps in the management of these complicated cases is discussed, as well as their outcomes. METHODS: The authors retrospectively reviewed the medical records of 5 patients who returned to the Neuro-Spine service at Texas Children's Hospital for erosion of spinal instrumentation through the skin between September 1, 2007, and October 31, 2012. Patient demographics and clinical and operative data were recorded. RESULTS: Risk factors such as young age (1 case), poor nutritional status (1 case), multiple previous surgeries (3 cases), severe neurological deficits (2 cases), and history of radiation therapy for malignancy (2 cases) were noted in the 5 patients. The paraspinous flap (4 cases) was the mainstay of the treatment. Follow-up ranged from 7.5 to 17.5 months (mean 11 ± 4.2 months). One of the patients required more than 1 procedure for revision of the wound. Cultures were positive in 2 of the 5 cases. Spinal instrumentation was removed in 3 of the 5 cases; however, in all 3 of the cases there was evidence of delayed instability that developed after the removal of spinal instrumentation. CONCLUSIONS: The use of local tissue flaps is safe and efficacious for treatment of posterior wound complications due to spinal instrumentation in children. Removal of spinal instrumentation should be avoided due to the development of delayed instability. Highly vascularized tissue is used to speed healing, clear bacteria, and eliminate dead space, obviating the need to remove contaminated spinal instrumentation.

Infected lumbar dermoid cyst mimicking intramedullary spinal cord tumor: Observations and outcomes.

We report two unusual cases of a 17-month-old boy with a previously undiagnosed lumbar dermal sinus tract terminating in an intradural dermoid cyst and holocord edema or syrinx, presenting with paraparesis and sphincter dysfunction secondary to an intramedullary abscess and a 26-month-old boy with a previously undiagnosed lumbar dermal sinus tract terminating in an infected dermoid cyst and intramedullary abscess, presenting with recurrent episodes of meningitis and hydrocephalus. Pre-operative magnetic resonance imaging (MRI) studies in these patients were initially confused for an intramedullary spinal cord tumor; however, the presence of an associated dermal sinus tract made this diagnosis of neoplasm less likely. Total excision of the dermal sinus tract, debulking of the dermoid cyst and drainage of the intramedullary abscess through an L1-L5 osteoplastic laminoplasty and midline myelotomy, followed by long-term antibiotic therapy resulted in a good functional recovery. Post-operative MRI of the spine showed removal of the dermoid cyst, decreased inflammatory granulation tissue and resolution of the holocord edema or syrinx. We also performed a literature review to determine the cumulative experience of management of intramedullary abscess in this rare clinical setting.

Spondylolysis of C-2 in children 3 years of age or younger: clinical presentation, radiographic findings, management, and outcomes with a minimum 12-month follow-up.

OBJECT: Cervical spondylolysis is a rare condition that results from a pars interarticularis defect. The C-6 level is the most frequently involved site in the cervical spine. Its clinical presentations range from incidental radiographic findings to neck pain and, rarely, neurological deficits. Although 150 patients with subaxial cervical spondylolysis have been reported, a mere 24 adult and pediatric patients with C-2 spondylolysis have been described. The long-term outcomes of very young children with bilateral C-2 spondylolysis are of great interest, yet only a few longitudinal studies exist. METHODS: The authors retrospectively reviewed 5 cases of bilateral C-2 spondylolysis at Texas Children's Hospital and Riley Children's Hospital; these were combined with 5 other cases in the literature, yielding a total of 10 patients. Data regarding the patients' age, sex, C2-3 angulation and displacement, associated spine anomalies, neurological deficits, treatment, and most recent follow-up were recorded. RESULTS: The patients' ages ranged from 3 to 36 months (mean 12.9 months). There were 6 boys and 4 girls. The C2-3 angulation, displacement, and width of pars defect were measured when available. The mean C2-3 angulation was 9.5° (range 1-34°), the mean C2-3 displacement was 4.78 mm (range 1.1-10.8 mm), and the mean width of the pars defect was 4.16 mm (range 0.9-7 mm). One patient developed myelopathy and spinal cord injury. All 10 of the patients were treated initially with conservative therapy: 3 with close observation alone, 1 with a rigid cervical collar, 4 with a Minerva jacket, 1 with a sternal-occipital-mandibular immobilizer, and 1 with a halo vest. Three patients ultimately underwent surgery for internal fixation due to progressive instability or development of neurological symptoms. All patients were neurologically intact at the last follow-up (mean 44.3 months, range 14-120 months). CONCLUSIONS: Based on the literature and the authors' own experience, they conclude that most very young children with C-2 spondylolysis remain neurologically intact and maintain stability in long-term follow-up despite the bony defect. This defect is often an asymptomatic incidental finding and may be managed conservatively. More aggressive therapy including surgery is indicated for those patients with a neurological deficit from spinal cord compromise secondary to stenosis and local C-2 kyphosis, progressive deformity, or worsening C2-3 instability.

Practice trends in the utilization of intraoperative neurophysiological monitoring in pediatric neurosurgery as a function of complication rate, and patient-, surgeon-, and procedure-related factors.

OBJECTIVE: Higher benchmarks in safety for patients undergoing neurosurgery have been introduced. With these principles, new tools and techniques were established, including intraoperative neurophysiological monitoring (IONM). Current trends as a function of patient-, surgeon-, and procedure-related factors and complication rates in the utilization of IONM as an adjunct to the practice of pediatric neurosurgery have not been investigated previously. METHODS: Between 2008 and 2011, 4467 neurosurgical procedures were performed on 2352 patients at Texas Children's Hospital. A retrospective chart review was performed in which surgeon, procedure, and patient characteristics, as well as perioperative complications, were recorded for IONM and non-IONM cases. RESULTS: Neurosurgical procedures performed with IONM steadily increased. Surgeon-related factors associated with IONM use included surgeons with <10 years of practice (P < .0001), and subspecialty interest in spine (P < .0001) and oncology (P = .0048). Procedure-related factors associated with IONM use included operations involving the spinal cord (P < .0001). Patient-related factors associated with IONM use included children older than 3 years of age and with increased American Society of Anesthesiologists score (P < .0001). The neurological complication rate in the IONM cohort (range 3.4% to 11.3%; mean 6.4%) was significantly higher compared to the non-IONM cohort (range 1.1% to 1.8%; mean 1.5%) (P < .0001). CONCLUSIONS: The percent of procedures performed with IONM increased. However, these trends do not seem governed by improvement to patient outcomes because the complication rates were higher in the IONM cohort than the non-IONM cohort.

Potential role of stem cells for neuropathic pain disorders.

Chronic neuropathic pain is a debilitating disease process associated with several medical disorders. Different from pain caused by inflammation, neuropathic pain is a diffuse pain disorder often found to be recalcitrant to the limited medical treatments available. Intractable nerve pain may benefit from other therapies capable of longer-lasting pain coverage or greater efficacy. A growing number of reports have emerged suggesting a role for stem cells as a cellular delivery source with neuroprotective agents opposing the effects of nerve damage. Here, the authors review the current experimental therapies examining the use of stem cells for the treatment of neuropathic pain disorders.

Isolated cervical spinal canal stenosis at C-1 in the pediatric population and in Williams syndrome.

OBJECT: Isolated cervical canal stenosis at the level of the atlas (C-1) is a rare cause of cervical myelopathy in the pediatric population. It has been associated with several genetic disorders including spondyloepiphysial dysplasia congenita, Down syndrome, and Klippel-Feil syndrome. The purpose of this study is to highlight the authors' experience with 4 additional pediatric cases, review the literature, and report a new association of this disease with Williams syndrome. METHODS: The medical records and radiological imaging studies of 4 patients treated at Texas Children's Hospital for symptomatic hypoplasia of the atlas were retrospectively reviewed. Pertinent patient demographic data, clinical presentation, imaging findings, and outcomes after surgery were recorded. A thorough literature review was performed, allowing the authors to compare and contrast their 4 cases to surgical cases already published in the literature. RESULTS: There were 11 boys and 1 girl in the aggregate series. The average age of the patients was 7 years (range 13 months-14 years), and the duration of symptoms prior to presentation was 6 months (range 0-36 months). The mean sagittal diameter of the spinal canal at the level of the atlas measured from the posterior aspect of the dens to the anterior aspect of the arch of C-1 was 11.9 mm (range 8.3-16 mm) in the aggregate series. In 2 new pediatric patients with hypoplasia of the atlas the disease was associated with Williams syndrome, which has not been previously described. Patients in the aggregate series were followed for an average of 18 months (range 3-50 months). Laminectomy of C-1 provided neurological improvement in all patients who presented. CONCLUSIONS: Isolated cervical spinal canal stenosis at the level of the atlas is a rare cause of cervical myelopathy. The authors hope that this report will prompt clinicians to consider it when searching for the origin of signs and symptoms of cervical myelopathy, especially in children.

Giant invasive spinal schwannoma in children: a case report and review of the literature.

INTRODUCTION: Giant invasive spinal schwannoma is defined as a tumor that extends over two or more vertebral levels, erodes vertebral bodies, and extends into the extraspinal space disrupting myofascial planes. Because of its rarity, there have been few published reports describing clinical features and surgical outcomes, especially in the pediatric patient population. CASE PRESENTATION: We analyzed the medical record, pathologic findings, and radiographic studies of a 14-year-old Hispanic boy who presented to Texas Children's Hospital with a three-month history of progressive spastic paraparesis. Preoperative computed tomography and magnetic resonance imaging reports showed a large mass lesion centered at the left T7-8 neural foramen with intra- and extraspinal extension, resulting in severe spinal cord compression and vertebral body erosion, and protrusion into the retropleural space and descending aorta. Our patient underwent a single-stage posterior approach for complete resection of the tumor with reconstruction and stabilization of the vertebral column. The pathological examination was consistent with schwannoma. At the six-month follow-up, our patient had resolution of preoperative symptoms and remains neurologically intact without any radiographic evidence of recurrent tumor. CONCLUSION: To the best of our knowledge, our case represents the fourth child with giant invasive spinal schwannoma reported in the literature. We describe our case and review the literature to discuss the aggregate clinical features, surgical strategies, and operative outcomes for giant invasive spinal schwannoma in the pediatric age group.