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.

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.

Socioeconomic and demographic factors in the diagnosis and treatment of Chiari malformation type I and syringomyelia

OBJECTIVE

The goal of this study was to assess the social determinants that influence access and outcomes for pediatric neurosurgical care for patients with Chiari malformation type I (CM-I) and syringomyelia (SM).

METHODS

The authors used retro- and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM-I and SM who received surgical treatment and had at least 1 year of follow-up data. Race, ethnicity, and insurance status were used as comparators for preoperative, treatment, and postoperative characteristics and outcomes.

RESULTS

A total of 637 patients met inclusion criteria, and race or ethnicity data were available for 603 (94.7%) patients. A total of 463 (76.8%) were non-Hispanic White (NHW) and 140 (23.2%) were non-White. The non-White patients were older at diagnosis (p = 0.002) and were more likely to have an individualized education plan (p < 0.01). More non-White than NHW patients presented with cerebellar and cranial nerve deficits (i.e., gait ataxia [p = 0.028], nystagmus [p = 0.002], dysconjugate gaze [p = 0.03], hearing loss [p = 0.003], gait instability [p = 0.003], tremor [p = 0.021], or dysmetria [p < 0.001]). Non-White patients had higher rates of skull malformation (p = 0.004), platybasia (p = 0.002), and basilar invagination (p = 0.036). Non-White patients were more likely to be treated at low-volume centers than at high-volume centers (38.7% vs 15.2%; p < 0.01). Non-White patients were older at the time of surgery (p = 0.001) and had longer operative times (p < 0.001), higher estimated blood loss (p < 0.001), and a longer hospital stay (p = 0.04). There were no major group differences in terms of treatments performed or complications. The majority of subjects used private insurance (440, 71.5%), whereas 175 (28.5%) were using Medicaid or self-pay. Private insurance was used in 42.2% of non-White patients compared to 79.8% of NHW patients (p < 0.01). There were no major differences in presentation, treatment, or outcome between insurance groups. In multivariate modeling, non-White patients were more likely to present at an older age after controlling for sex and insurance status (p < 0.01). Non-White and male patients had a longer duration of symptoms before reaching diagnosis (p = 0.033 and 0.004, respectively).

CONCLUSIONS

Socioeconomic and demographic factors appear to influence the presentation and management of patients with CM-I and SM. Race is associated with age and timing of diagnosis as well as operating room time, estimated blood loss, and length of hospital stay. This exploration of socioeconomic and demographic barriers to care will be useful in understanding how to improve access to pediatric neurosurgical care for patients with CM-I and SM.

Extradural decompression versus duraplasty in Chiari malformation type I with syrinx: outcomes on scoliosis from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Scoliosis is common in patients with Chiari malformation type I (CM-I)-associated syringomyelia. While it is known that treatment with posterior fossa decompression (PFD) may reduce the progression of scoliosis, it is unknown if decompression with duraplasty is superior to extradural decompression.

METHODS

A large multicenter retrospective and prospective registry of 1257 pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for patients with scoliosis who underwent PFD with or without duraplasty.

RESULTS

In total, 422 patients who underwent PFD had a clinical diagnosis of scoliosis. Of these patients, 346 underwent duraplasty, 51 received extradural decompression alone, and 25 were excluded because no data were available on the type of PFD. The mean clinical follow-up was 2.6 years. Overall, there was no difference in subsequent occurrence of fusion or proportion of patients with curve progression between those with and those without a duraplasty. However, after controlling for age, sex, preoperative curve magnitude, syrinx length, syrinx width, and holocord syrinx, extradural decompression was associated with curve progression > 10°, but not increased occurrence of fusion. Older age at PFD and larger preoperative curve magnitude were independently associated with subsequent occurrence of fusion. Greater syrinx reduction after PFD of either type was associated with decreased occurrence of fusion.

CONCLUSIONS

In patients with CM-I, syrinx, and scoliosis undergoing PFD, there was no difference in subsequent occurrence of surgical correction of scoliosis between those receiving a duraplasty and those with an extradural decompression. However, after controlling for preoperative factors including age, syrinx characteristics, and curve magnitude, patients treated with duraplasty were less likely to have curve progression than patients treated with extradural decompression. Further study is needed to evaluate the role of duraplasty in curve stabilization after PFD.

Occipital-Cervical Fusion and Ventral Decompression in the Surgical Management of Chiari-1 Malformation and Syringomyelia: Analysis of Data From the Park-Reeves Syringomyelia Research Consortium

BACKGROUND

Occipital-cervical fusion (OCF) and ventral decompression (VD) may be used in the treatment of pediatric Chiari-1 malformation (CM-1) with syringomyelia (SM) as adjuncts to posterior fossa decompression (PFD) for complex craniovertebral junction pathology.

OBJECTIVE

To examine factors influencing the use of OCF and OCF/VD in a multicenter cohort of pediatric CM-1 and SM subjects treated with PFD.

METHODS

The Park-Reeves Syringomyelia Research Consortium registry was used to examine 637 subjects with cerebellar tonsillar ectopia ≥ 5 mm, syrinx diameter ≥ 3 mm, and at least 1 yr of follow-up after their index PFD. Comparisons were made between subjects who received PFD alone and those with PFD + OCF or PFD + OCF/VD.

RESULTS

All 637 patients underwent PFD, 505 (79.2%) with and 132 (20.8%) without duraplasty. A total of 12 subjects went on to have OCF at some point in their management (PFD + OCF), whereas 4 had OCF and VD (PFD + OCF/VD). Of those with complete data, a history of platybasia (3/10, P = .011), Klippel-Feil (2/10, P = .015), and basilar invagination (3/12, P < .001) were increased within the OCF group, whereas only basilar invagination (1/4, P < .001) was increased in the OCF/VD group. Clivo-axial angle (CXA) was significantly lower for both OCF (128.8 ± 15.3°, P = .008) and OCF/VD (115.0 ± 11.6°, P = .025) groups when compared to PFD-only group (145.3 ± 12.7°). pB-C2 did not differ among groups.

CONCLUSION

Although PFD alone is adequate for treating the vast majority of CM-1/SM patients, OCF or OCF/VD may be occasionally utilized. Cranial base and spine pathologies and CXA may provide insight into the need for OCF and/or OCF/VD.

Dural augmentation approaches and complication rates after posterior fossa decompression for Chiari I malformation and syringomyelia: a Park-Reeves Syringomyelia Research Consortium study

OBJECTIVE

Posterior fossa decompression with duraplasty (PFDD) is commonly performed for Chiari I malformation (CM-I) with syringomyelia (SM). However, complication rates associated with various dural graft types are not well established. The objective of this study was to elucidate complication rates within 6 months of surgery among autograft and commonly used nonautologous grafts for pediatric patients who underwent PFDD for CM-I/SM.

METHODS

The Park-Reeves Syringomyelia Research Consortium database was queried for pediatric patients who had undergone PFDD for CM-I with SM. All patients had tonsillar ectopia ≥ 5 mm, syrinx diameter ≥ 3 mm, and ≥ 6 months of postoperative follow-up after PFDD. Complications (e.g., pseudomeningocele, CSF leak, meningitis, and hydrocephalus) and postoperative changes in syrinx size, headaches, and neck pain were compared for autograft versus nonautologous graft.

RESULTS

A total of 781 PFDD cases were analyzed (359 autograft, 422 nonautologous graft). Nonautologous grafts included bovine pericardium (n = 63), bovine collagen (n = 225), synthetic (n = 99), and human cadaveric allograft (n = 35). Autograft (103/359, 28.7%) had a similar overall complication rate compared to nonautologous graft (143/422, 33.9%) (p = 0.12). However, nonautologous graft was associated with significantly higher rates of pseudomeningocele (p = 0.04) and meningitis (p < 0.001). The higher rate of meningitis was influenced particularly by the higher rate of chemical meningitis (p = 0.002) versus infectious meningitis (p = 0.132). Among 4 types of nonautologous grafts, there were differences in complication rates (p = 0.02), including chemical meningitis (p = 0.01) and postoperative nausea/vomiting (p = 0.03). Allograft demonstrated the lowest complication rates overall (14.3%) and yielded significantly fewer complications compared to bovine collagen (p = 0.02) and synthetic (p = 0.003) grafts. Synthetic graft yielded higher complication rates than autograft (p = 0.01). Autograft and nonautologous graft resulted in equal improvements in syrinx size (p < 0.0001). No differences were found for postoperative changes in headaches or neck pain.

CONCLUSIONS

In the largest multicenter cohort to date, complication rates for dural autograft and nonautologous graft are similar after PFDD for CM-I/SM, although nonautologous graft results in higher rates of pseudomeningocele and meningitis. Rates of meningitis differ among nonautologous graft types. Autograft and nonautologous graft are equivalent for reducing syrinx size, headaches, and neck pain.

Factors associated with syrinx size in pediatric patients treated for Chiari malformation type I and syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Factors associated with syrinx size in pediatric patients undergoing posterior fossa decompression (PFD) or PFD with duraplasty (PFDD) for Chiari malformation type I (CM-I) with syringomyelia (SM; CM-I+SM) are not well established.

METHODS

Using the Park-Reeves Syringomyelia Research Consortium registry, the authors analyzed variables associated with syrinx radiological outcomes in patients (< 20 years old at the time of surgery) with CM-I+SM undergoing PFD or PFDD. Syrinx resolution was defined as an anteroposterior (AP) diameter of ≤ 2 mm or ≤ 3 mm or a reduction in AP diameter of ≥ 50%. Syrinx regression or progression was defined using 1) change in syrinx AP diameter (≥ 1 mm), or 2) change in syrinx length (craniocaudal, ≥ 1 vertebral level). Syrinx stability was defined as a < 1-mm change in syrinx AP diameter and no change in syrinx length.

RESULTS

The authors identified 380 patients with CM-I+SM who underwent PFD or PFDD. Cox proportional hazards modeling revealed younger age at surgery and PFDD as being independently associated with syrinx resolution, defined as a ≤ 2-mm or ≤ 3-mm AP diameter or ≥ 50% reduction in AP diameter. Radiological syrinx resolution was associated with improvement in headache (p < 0.005) and neck pain (p < 0.011) after PFD or PFDD. Next, PFDD (p = 0.005), scoliosis (p = 0.007), and syrinx location across multiple spinal segments (p = 0.001) were associated with syrinx diameter regression, whereas increased preoperative frontal-occipital horn ratio (FOHR; p = 0.007) and syrinx location spanning multiple spinal segments (p = 0.04) were associated with syrinx length regression. Scoliosis (HR 0.38 [95% CI 0.16-0.91], p = 0.03) and smaller syrinx diameter (5.82 ± 3.38 vs 7.86 ± 3.05 mm; HR 0.60 [95% CI 0.34-1.03], p = 0.002) were associated with syrinx diameter stability, whereas shorter preoperative syrinx length (5.75 ± 4.01 vs 9.65 ± 4.31 levels; HR 0.21 [95% CI 0.12-0.38], p = 0.0001) and smaller pB-C2 distance (6.86 ± 1.27 vs 7.18 ± 1.38 mm; HR 1.44 [95% CI 1.02-2.05], p = 0.04) were associated with syrinx length stability. Finally, younger age at surgery (8.19 ± 5.02 vs 10.29 ± 4.25 years; HR 1.89 [95% CI 1.31-3.04], p = 0.01) was associated with syrinx diameter progression, whereas increased postoperative syrinx diameter (6.73 ± 3.64 vs 3.97 ± 3.07 mm; HR 3.10 [95% CI 1.67-5.76], p = 0.003), was associated with syrinx length progression. PFD versus PFDD was not associated with syrinx progression or reoperation rate.

CONCLUSIONS

These data suggest that PFDD and age are independently associated with radiological syrinx improvement, although forthcoming results from the PFDD versus PFD randomized controlled trial (NCT02669836, clinicaltrials.gov) will best answer this question.

Modification of the Fetal Profile Line to Measure Reversal of Forehead Slope after Early Repair of Frontoethmoidal Encephalocele

Objective  Congenital frontoethmoidal encephaloceles are associated with a shallow sloping forehead. We (1) sought to determine if early repair reverses abnormal forehead slope, and (2) assessed a modification of the fetal profile (FP) line to assess results. Design  Study of two cases. Participants  Newborns with frontoethmoidal encephaloceles repaired prior to the age of 4 months with cranial base bone grafting. Main Outcome Measures  Forehead slope was assessed using a modification of the FP line, defined as the line that passes through the anterior border of the mandible and nasion, on pre and postoperative magnetic resonance imaging (MRI) in the midsagittal plane. A modified FP (mFP) line anterior to the forehead was " - ", while a posterior (normal) mFP line was " + ." The largest distance from the mFP line to the forehead was measured. Results  Both infants underwent bifrontal craniotomy, excision of encephalocele, and repair of cribriform plate defect using full-thickness autologous parietal bone before the age of 4 months. Preoperatively, the mFP line was -20.6 mm in case 1, and -9.8 mm in case 2. In both cases, follow-up MRI showed excellent reversal of forehead slope and normal calvarium development. The mFP line improved to +7.4 (age = 16 months) in case 1, and +7.6 (age = 11 months) in case 2. The parietal bone donor site ossified completely within 3 months in both cases. Conclusion  Early repair with bone grafting can promote normal frontal bone development and improve forehead slope. The mFP line is a useful method to measure degree of forehead slope.

Radiological and clinical predictors of scoliosis in patients with Chiari malformation type I and spinal cord syrinx from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Scoliosis is frequently a presenting sign of Chiari malformation type I (CM-I) with syrinx. The authors' goal was to define scoliosis in this population and describe how radiological characteristics of CM-I and syrinx relate to the presence and severity of scoliosis.

METHODS

A large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°).

RESULTS

Based on available imaging of patients with CM-I and syrinx, 260 of 825 patients (31%) had a clear diagnosis of scoliosis based on radiographs or coronal MRI. Forty-nine patients (5.9%) did not have scoliosis, and in 516 (63%) patients, a clear determination of the presence or absence of scoliosis could not be made. Comparison of patients with and those without a definite scoliosis diagnosis indicated that scoliosis was associated with wider syrinxes (8.7 vs 6.3 mm, OR 1.25, p < 0.001), longer syrinxes (10.3 vs 6.2 levels, OR 1.18, p < 0.001), syrinxes with their rostral extent located in the cervical spine (94% vs 80%, OR 3.91, p = 0.001), and holocord syrinxes (50% vs 16%, OR 5.61, p < 0.001). Multivariable regression analysis revealed syrinx length and the presence of holocord syrinx to be independent predictors of scoliosis in this patient cohort. Scoliosis was not associated with sex, age at CM-I diagnosis, tonsil position, pB-C2 distance (measured perpendicular distance from the ventral dura to a line drawn from the basion to the posterior-inferior aspect of C2), clivoaxial angle, or frontal-occipital horn ratio. Average curve magnitude was 29.9°, and 37.7% of patients had a left thoracic curve. Older age at CM-I or syrinx diagnosis (p < 0.0001) was associated with greater curve magnitude whereas there was no association between syrinx dimensions and curve magnitude.

CONCLUSIONS

Syrinx characteristics, but not tonsil position, were related to the presence of scoliosis in patients with CM-I, and there was an independent association of syrinx length and holocord syrinx with scoliosis. Further study is needed to evaluate the nature of the relationship between syrinx and scoliosis in patients with CM-I.

Endovascular management of a vein of Galen aneurysmal malformation in an infant with challenging femoral arterial access

A 5-month-old infant was to be treated with elective transarterial embolization for a vein of Galen aneurysmal malformation (VGAM). A team of endovascular surgical neuroradiologists, pediatric interventional radiologists, and pediatric cardiologists attempted conventional femoral arterial access, which was unsuccessful given the small caliber of the femoral arteries and superimposed severe vasospasm. Thereafter, eventual arterial access was achieved by navigating from the venous to the arterial system across the patent foramen ovale following a right femoral venous access. Embolization was then successfully performed. At a later date, the child underwent successful transvenous balloon-assisted embolization and eventual arterial embolization with cure of the VGAM.

Abstract A08: IGF1R as a key target in high risk, metastatic medulloblastoma

The risk or presence of metastasis in childhood medulloblastoma represents a substantial cause of morbidity and mortality. Relatively little has been known about the molecular mechanisms of medulloblastoma dissemination throughout the cerebrospinal axis. To determine potential interventions that address both metastasis and tumor growth, we examined the expression of cytokines and growth factors in the CSF of metastatic medulloblastoma patients that were also present in the conditioned media of metastatic, MYC amplified medulloblastoma cell lines and/or cell culture models of the leptomeninges. The presence of IGF1, the IGF-sequestering protein Igfbp3, which can be cleaved by metal metalloproteases (MMP) and the serine protease tPA, and the presence of corresponding protease modulators TIMP1 and SerpinE1/PAI-1, led us to explore the bioactivity of IGF1 in medulloblastoma. IGF1 led not only to receptor phosphorylation but also increased migration and increased relative cell growth. A tumor cell viability screen of 60 clinically-related compounds prioritized IGF1R inhibitors. Our findings support a model whereby medulloblastoma tumor cells actively migrate, rather than arrive passively, to the leptomeningeal cell surface and provide a rationale for exploring IGF1R as a target for therapeutics in future clinical trials.

Citation Format: Matthew N. Svalina, Ken Kikuchi, Jinu Abraham, Sangeet Lal, Monika A. Davare, Jennifer L. Peckham, Yoon-Jae Cho, Melanie Jackson, Daniel J. Guillaume, Nathan R. Selden, Darell D. Bigner, Kellie J. Nazemi, Sarah C. Green, Christopher L. Corless, Sakir Gultekin, Brian P. Rubin, Randall Woltjer, Charles Keller. IGF1R as a key target in high risk, metastatic medulloblastoma. [abstract]. In: Proceedings of the AACR Special Conference: Advances in Brain Cancer Research; May 27-30, 2015; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2015;75(23 Suppl):Abstract nr A08.

The role of percutaneous embolization techniques in the management of dural sinus malformations with atypical angioarchitecture in neonates: report of 2 cases

Dural sinus malformations (DSMs) are rare congenital malformations that can be midline or lateral in location. Midline DSMs have been reported to have a worse prognosis than lateral DSMs and have traditionally been more difficult to manage. The authors report 2 unusual manifestations of midline DSMs and their management with percutaneous transfontanelle embolization. The first patient (Case 1) presented at 21 days of life with a large midline DSM and multiple highflow dural and pial arteriovenous shunts. The child developed congestive cardiac failure and venous congestion with intracranial hemorrhage and seizures within a few weeks. The second patient (Case 2) presented with a large midline DSM found on prenatal imaging that was determined to be a purely venous malformation on postnatal evaluation. This large malformation resulted in consumptive coagulopathy and apneic episodes from brainstem compression. The patient in Case 1 was treated initially with endovascular embolization and eventually with curative percutaneous-transfontanelle embolization. The patient in Case 2 was treated with percutaneous transfontanelle embolization in combination with posterior fossa decompression and cranial expansion surgery.

Prognostic value of newborn hearing screening in patients with myelomeningocele

OBJECT

Brainstem dysfunction occurs in a minority of patients with myelomeningocele (MMC), most of whom have Chiari Type II malformation. Some surgeons advocate early identification of these patients for craniocervical decompression to avoid significant mortality. The auditory brainstem response has been found to be abnormal in most children with MMC. The present study examines whether failure of routine newborn hearing screening (NHS) predicts brainstem dysfunction in MMC patients.

METHODS

The charts of 40 newborns with MMC and 50 newborns without MMC who stayed in the neonatal intensive care unit were reviewed. Results of NHS, brainstem symptoms, birth demographics, and surgical history were retrospectively examined. Differences in the presence and onset of brainstem symptoms by NHS result were assessed.

RESULTS

Failure of NHS was more common among newborns with MMC who developed brainstem symptoms (31%, 4 of 13 patients) than among newborns without MMC (0%, 0 of 50 patients; p = 0.001). Among the 40 newborns with MMC, brainstem symptoms were more common in those who failed NHS (80%, 4 of 5 patients) than in those who passed (26%, 9 of 35 patients; p = 0.031). Respiratory symptom onset occurred later in patients who failed NHS (median 16 months) than among those who passed (median 0 months; p = 0.022). The positive and negative predictive values of NHS for brainstem dysfunction in MMC were 0.80 and 0.74, respectively.

CONCLUSIONS

Results of NHS may help predict future brainstem dysfunction in patients with MMC and may be useful to incorporate into prognostic assessment and surgical decision making.

Late-onset ornithine transcarbamylase deficiency: treatment and outcome of hyperammonemic crisis

Hyperammonemic crises in ornithine transcarbamylase deficiency (OTC) can be associated with devastating cerebral edema resulting in severe long-term neurologic impairment and death. We present an 8-year-old boy who had late-onset OTC deficiency in which early and aggressive management of hyperammonemia and associated cerebral edema, including therapeutic hypothermia and barbiturate-induced coma, resulted in favorable neurologic outcome. Our patient presented with vomiting and altered mental status, and was found to have a significantly elevated serum ammonia level of 1561 μmol/L. Hyperammonemia was managed with hemodialysis, 10% sodium phenylacetate, 10% sodium benzoate, L-arginine, intravenous 10% dextrose, intralipids, and protein restriction. He developed significant cerebral edema with intracranial pressures >20 mm Hg, requiring treatment with 3% saline and mannitol. Despite this treatment our patient continued to have elevated intracranial pressures, which were treated aggressively with non-conventional modalities including therapeutic hypothermia, barbiturate-induced coma, and external ventricular drainage. This therapy resulted in stabilization of hyperammonemia and resolution of cerebral edema. Molecular testing later revealed a hemizygous mutation within the OTC gene. Neuropsychological testing 1 year after discharge showed normal intelligence with no visual-motor deficits, minor deficits in working memory and processing speed, and slightly below average processing speed and executive functioning.

Central nervous system stem cell transplantation for children with neuronal ceroid lipofuscinosis

OBJECT

Infantile and late-infantile neuronal ceroid lipofuscinoses (NCLs) are invariably fatal lysosomal storage diseases associated with defects in lysosomal enzyme palmitoyl-protein thioesterase 1 (PPT-1) or tripeptidyl peptidase 1 (TPP1) activity. Previous preclinical studies have demonstrated that human CNS stem cells (HuCNS-SCs) produce both PPT-1 and TPP1 and result in donor cell engraftment and reduced accumulation of storage material in the brain when tested in an NCL mouse model.

METHODS

HuCNS-SC transplantation was tested in an open-label dose-escalation Phase I clinical trial as a potential treatment for infantile and late-infantile NCL. Study design included direct neurosurgical transplantation of allogeneic HuCNS-SCs into the cerebral hemispheres and lateral ventricles accompanied by 12 months of immunosuppression.

RESULTS

Six children with either the infantile or late-infantile forms of NCL underwent low- (3 patients) and high- (3 patients) dose transplantation of HuCNS-SCs followed by immunosuppression. The surgery, immunosuppression, and cell transplantation were well tolerated. Adverse events following transplantation were consistent with the underlying disease, and none were directly attributed to the donor cells. Observations regarding efficacy of the intervention were limited by the enrollment criteria requiring that patients be in advanced stages of disease.

CONCLUSIONS

This study represents the first-in-human clinical trial involving transplantation of a purified population of human neural stem cells for a neurodegenerative disorder. The feasibility of this approach and absence of transplantation-related serious adverse events support further exploration of HuCNS-SC transplantation as a potential treatment for select subtypes of NCL, and possibly for other neurodegenerative disorders.

Optimal timing of autologous cranioplasty after decompressive craniectomy in children

OBJECT

The object of this study was to determine if early cranioplasty after decompressive craniectomy for elevated intracranial pressure in children reduces complications.

METHODS

Sixty-one consecutive cases involving pediatric patients who underwent autologous cranioplasty after decompressive craniectomy for raised intracranial pressure at a single academic children's hospital over 15 years were studied retrospectively.

RESULTS

Sixty-one patients were divided into early (< 6 weeks; 28 patients) and late (≥ 6 weeks; 33 patients) cranioplasty cohorts. The cohorts were similar except for slightly lower age in the early (8.03 years) than the late (10.8 years) cranioplasty cohort (p < 0.05). Bone resorption after cranioplasty was significantly more common in the late (42%) than the early (14%) cranioplasty cohort (p < 0.05; OR 5.4). No other complication differed in incidence between the cohorts.

CONCLUSIONS

After decompressive craniectomy for raised intracranial pressure in children, early (< 6 weeks) cranioplasty reduces the occurrence of reoperation for bone resorption, without altering the incidence of other complications.

Dual contrast perfusion MRI in a single imaging session for assessment of pediatric brain tumors

Ferumoxytol, an iron nanoparticle used as an intravascular contrast agent for perfusion magnetic resonance imaging (MRI), has never been explored in the pediatric population. The purpose of this prospective study is to characterize the vascular and permeability properties of pediatric brain tumors using two contrast agents during a single imaging session: ferumoxytol for dynamic susceptibility weighted contrast (DSC) MRI and gadoteridol for dynamic contrast-enhanced (DCE) MRI. In a single imaging session, patients received intravenous ferumoxytol for DSC MRI followed by gadoteridol for DCE MRI. Relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), transfer coefficient (K(trans)), and extravascular extracellular space volume fraction (v(e)) of the brain lesions were calculated. Patients underwent serial imaging sessions over the course of 2 years. Of the 7 patients enrolled thus far, none has experienced an adverse event. Two patients with medulloblastoma were enrolled preoperatively. In the first, rCBV(max), rCBF, K(trans) max, and v(e) max values were 3.74, 3.12, 0.47 min (-1), and 0.08, respectively, while in the second patient, rCBV(max), rCBF, K(trans) max, and v(e) max values were 4.72, 3.47, 0.60 min(-1), and 0.05, respectively. Four patients were enrolled after new gadolinium enhancement was noted in the tumor resection cavity. In 80 % of these lesions, rCBV was <1 suggestive of pseudoprogression secondary to radiochemotherapy. These preliminary results demonstrate that use of ferumoxytol and gadoteridol contrast agents during a single imaging session is feasible, safe, and appears useful for assessing tumor perfusion and permeability characteristics in children.

Cerebrospinal fluid shunting and hearing loss in patients treated for medulloblastoma

OBJECT

Cerebrospinal fluid shunting has previously been associated with hearing loss. Although the mechanism for this is unclear, it is thought that changes in CSF pressure can affect cochlear physiology via endolymph expansion in the setting of a patent cochlear aqueduct. Patients undergoing radiation and cisplatin chemotherapy are at risk for hearing loss. The authors hypothesized that the incidence and severity of hearing loss in patients undergoing radiation and chemotherapy for medulloblastoma would be greater in those with shunts than in those without shunts.

METHODS

Baseline and longitudinal audiology data were collected in 33 patients with medulloblastoma who were receiving radiation and cisplatin chemotherapy. Additional data included age, sex, details of shunt placement and revision, and details of chemotherapy and radiation. Hearing sensitivity and peripheral auditory function measures included pure tone audiometry, immittance audiometry, and distortion product evoked otoacoustic emissions. Ototoxicity was determined according to the American Speech-Language-Hearing Association criteria. Severity of hearing loss was determined using the Brock hearing loss grades. Incidence of hearing loss and association with shunting was determined.

RESULTS

Thirteen (39.4%) of the 33 patients evaluated had undergone shunt placement. Hearing loss occurred in 14 (70%) of 20 patients without shunts and in 13 (100%) of 13 patients with shunts. The difference between the rates of hearing loss in patients with shunts versus those without the devices was highly significant (p = 0.0008). The odds ratio for hearing loss in patients with a CSF shunt compared with those without a shunt was 23.49 (95% CI 4.21-131.15). Age, side of shunt, evidence of dissemination, diameter of cochlear aqueduct, and treatment protocol did not have a significant effect on shunt-related ototoxicity.

CONCLUSIONS

This study suggests an independent association between CSF shunting and hearing loss in children undergoing treatment for medulloblastoma, laying the foundation for a prospective study evaluating hearing loss in children with shunts who are not treated with ototoxic therapy.

Magnetic resonance imaging of intracranial tumors: intra-patient comparison of gadoteridol and ferumoxytol

This study aims to compare gadoteridol with ferumoxytol for contrast-enhanced and perfusion-weighted (PW) MRI of intracranial tumors. The final analysis included 26 patients, who underwent 3 consecutive days of 3T MRI. Day 1 consisted of anatomical pre- and postcontrast images, and PW MRI was acquired using gadoteridol (0.1 mmol/kg). On Day 2, the same MRI sequences were obtained with ferumoxytol (510 mg) and on Day 3, the anatomical images were repeated to detect delayed ferumoxytol-induced signal changes. The T₁-weighted images were evaluated qualitatively and quantitatively for enhancement volume and signal intensity (SI) changes; PW data were used to estimate the relative cerebral blood volume (rCBV). All 26 lesions showed 24-hour T₁-weighted ferumoxytol enhancement; 16 also had T₂-weighted hypointensities. In 6 patients, ferumoxytol-induced signal changes were noted in areas with no gadoteridol enhancement. Significantly greater (P< .0001) SI changes were seen with gadoteridol, and qualitative analyses (lesion border delineation, internal morphology, contrast enhancement) also showed significant preferences (P= .0121; P = .0015; P < .0001, respectively) for this agent. There was no significant difference in lesion enhancement volumes between contrast materials. The ferumoxytol-rCBV values were significantly higher (P = .0016) compared with the gadoteridol-rCBV values. In conclusion, ferumoxytol provides important information about tumor biology that complements gadoteridol imaging. The rCBV measurements indicate areas of tumor undergoing rapid growth, whereas the 24-hour scans mark the presence of inflammatory cells. Both of these functions provide useful information about tumor response to treatment. We suggest that dynamic and anatomical imaging with ferumoxytol warrant further assessment in brain tumor therapy.

Minimally invasive neurosurgery for cerebrospinal fluid disorders

This article focuses on minimally invasive approaches used to address disorders of cerebrospinal fluid (CSF) circulation. The author covers the primary CSF disorders that are amenable to minimally invasive treatment, including aqueductal stenosis, fourth ventricular outlet obstruction (including Chiari malformation), isolated lateral ventricle, isolated fourth ventricle, multiloculated hydrocephalus, arachnoid cysts, and tumors that block CSF flow. General approaches to evaluating disorders of CSF circulation, including detailed imaging studies, are discussed. Approaches to minimally invasive management of such disorders are described in general, and for each specific entity. For each procedure, indications, surgical technique, and known outcomes are detailed. Specific complications as well as strategies for their avoidance and management are addressed. Lastly, future directions and the need for structured outcome studies are discussed.

Laparoscopic-induced pneumocephalus in a patient with a ventriculoperitoneal shunt

The authors report the case of laparoscopic-induced pneumocephalus in a ventriculoperitoneal shunt (VPS) patient undergoing a transperitoneal laparoscopic procedure. This case represents the first instance, to our knowledge, of forced retrograde air through a Holter valve placed 20 years ago. Abdominal laparoscopic surgery is a minimally invasive procedure utilized for a wide spectrum of abdominal and pelvic disorders. VPS systems for cerebrospinal fluid diversion are used to treat hydrocephalus. We present a case of laparoscopic-induced pneumocephalus in a VPS patient undergoing a transperitoneal laparoscopic procedure.

Intra-arterial chemotherapy with osmotic blood-brain barrier disruption for aggressive oligodendroglial tumors: results of a phase I study

OBJECTIVE

Refractory anaplastic oligodendroglioma and oligoastrocytoma tumors are challenging to treat. This trial primarily evaluated toxicity and estimated the maximum tolerated dose of intra-arterial (IA) melphalan, IA carboplatin, and intravenous (IV) etoposide phosphate in conjunction with blood-brain barrier disruption in these tumors. The secondary measure was efficacy.

METHODS

Thirteen patients with temozolomide-refractory anaplastic oligodendroglioma (11 patients) or oligoastrocytoma (2 patients) underwent blood-brain barrier disruption with carboplatin (IA, 200 mg/m(2)/d), etoposide phosphate (IV, 200 mg/m(2)/d), and melphalan (IA, dose escalation) every 4 weeks, for up to 1 year. Patients underwent melphalan dose escalation (4, 8, 12, 16, and 20 mg/m(2)/d) until the maximum tolerated dose (1 level below that producing grade 4 toxicity) was determined. Toxicity and efficacy were assessed.

RESULTS

Two of 4 patients receiving IA melphalan at 8 mg/m(2)/d developed grade 4 thrombocytopenia; thus, the melphalan maximum tolerated dose was 4 mg/m/d. Adverse events included asymptomatic subintimal tear (1 patient) and grade 4 thrombocytopenia (3 patients). Two patients demonstrated complete response, 3 had partial responses, 5 demonstrated stable disease, and 3 progressed. Median overall progression-free survival was 11 months. Patients with complete or partial response demonstrated deletion of chromosomes 1p and 19q. In the 5 patients with stable disease, 2 demonstrated 1p and 19q deletion, and 3 demonstrated 19q deletion only.

CONCLUSION

In patients with anaplastic oligodendroglioma or oligoastrocytoma tumors in whom temozolomide treatment has failed, osmotic blood-brain barrier disruption with IA carboplatin, IV etoposide phosphate, and IA melphalan (4 mg/m(2)/d for 2 days) shows acceptable toxicity and encouraging efficacy, especially in patients demonstrating 1p and/or 19q deletion.

Human embryonic stem cells: a potential source of transplantable neural progenitor cells

The primary therapeutic goal of embryonic stem cell (ESC) research is cell replacement therapy. During the last decade, great strides have been made in developing in vitro protocols for differentiating human ESCs into neuroepithelial progenitors. More recent progress has been made in further directing them into becoming cells with specialized regional and neurotransmitter identities, such as midbrain dopaminergic and spinal motor neurons. Along with directed differentiation, other current efforts are aimed at efficient enrichment, avoidance of immune rejection, demonstration of functional integration, genetic modification to regulate neurotransmitter and factor release, directed axon growth, in vivo cell tracking, and measures to ensure safety. This review will focus on the potential of ESCs as a source of transplantable cells for use in cell replacement therapy.

Cellular therapy for childhood neurodegenerative disease. Part I: rationale and preclinical studies

✓ Successful cellular replacement in the diseased human central nervous system (CNS) faces numerous hurdles. In this first installment of a 2-part review, the authors report on the preclinical challenges involved in preparing for a major Phase I trial investigating the safety of human neural stem cell transplantation in a lysosomal storage disorder. Specifically, they discuss choice of the ideal disease for treatment, best donor cell type and source for implantation, the in vitro and in vivo methods used to estimate safety and efficacy, the challenges to noninvasive tracking of cells after transplantation, and the unique issues related to the immunology of CNS cellular transplantation.

Cellular therapy for childhood neurodegenerative disease. Part II: clinical trial design and implementation

✓ Cellular replacement therapy attempts to improve functioning of the diseased human central nervous system (CNS). In this second installment of a 2-part review, the authors discuss the major challenges to the translation of in vitro and animal studies of neural stem cell (NSC) therapy in the clinical setting. This analysis details the problems unique to the design of clinical trials using human NSCs, outlines patient selection practices, describes surgical techniques for cellular transplantation, and reviews the regulatory issues and ethical concerns in trials involving neurologically impaired children.

Human embryonic stem cell-derived neural precursors develop into neurons and integrate into the host brain

Whether and how in-vitro-produced human neural precursors mature and integrate into the brain are crucial to the utility of human embryonic stem (hES) cells in treating neurological disorders. After transplantation into the ventricles of neonatal immune-deficient mice, hES-cell-derived neural precursors stopped expressing the cell division marker Ki67, except in neurogenic areas, and differentiated into neurons and then glia in a temporal course intrinsic to that of human cells regardless of location. The human cells located in the gray matter became neurons in the olfactory bulb and striatum, whereas those in the white matter produced exclusively glia. Importantly, the grafted human cells formed synapses. Thus, the in-vitro-produced human neural precursors follow their intrinsic temporal program to produce neurons and glia and, in response to environmental signals, generate cells appropriate to their target regions and integrate into the brain.