Todd C. Hankinson

Surgical treatment of moyamoya syndrome in patients with sickle cell anemia: outcome following encephaloduroarteriosynangiosis.

OBJECTIVES Children with sickle cell anemia (SCA) and moyamoya syndrome carry a significant risk of ischemic stroke. Given the success of encephaloduroarteriosynangiosis (EDAS) or pial synangiosis in the treatment of moyamoya disease, the purpose of this study was to examine whether it reliably and durably protected children with SCA and moyamoya syndrome against cerebrovascular complications. METHODS The authors retrospectively reviewed a series of 12 patients with SCA who developed clinical and/or radiological evidence of moyamoya syndrome and underwent EDAS. RESULTS Eleven patients (92%) presented following a cerebrovascular accident (CVA), transient ischemic attack (TIA), or seizure. Magnetic resonance (MR) imaging or angiography suggested moyamoya vascular changes, and cerebral angiography confirmed the diagnosis in all 12 patients. At the time of surgery, the median age was 12.3 years (range 6.8-19.4 years). Ten (83%) of 12 patients had a history of CVA, and 4 of these patients were compliant with a transfusion protocol at the time of their CVA. Bilateral (7 patients) or unilateral (5 patients) EDAS was performed without complications. The mean follow-up period was 46.8 months (range 8.1-106 months). During the follow-up period, 2 patients (16.7%) suffered cerebrovascular events. One patient, who was stroke-free preoperatively, suffered a CVA 3 weeks after the procedure. The other patient suffered a single left lower-extremity TIA 18 months following right-sided EDAS. She returned to her neurological baseline condition and remains stable 53 months postoperatively. Seven patients underwent follow-up angiography or MR angiography, and evidence of revascularization was noted in all cases. At this time, no patient has developed progressive disease requiring a contralateral procedure after unilateral EDAS. CONCLUSIONS The EDAS procedure is a safe and effective treatment option in patients with SCA who develop moyamoya syndrome.

Duraplasty or not? An evidence-based review of the pediatric Chiari I malformation

ObjectivesFew studies are available that directly compare dural opening with and without additional intradural maneuvers. Therefore, the current review analyzed the available literature regarding this topic.MethodsAn Ovid MEDLINE search was completed using each of the terms “Chiari malformation,” “syringomyelia,” “syrinx,” “syringohydromyelia” in combination with “child” or “pediatric.” Publications were considered relevant if they reported the results of posterior fossa decompression without dural opening (PFD) to posterior fossa decompression with duraplasty (PFDD). The included studies were divided into three categories based upon the surgical techniques studied. The first group of papers included works that directly compared PFD to PFDD. The second group included studies in which all patients were treated with PFD. The third group included studies in which all patients were treated with PFDD. Three outcome parameters were assessed: (1) improvement of clinical signs/symptoms, (2) syrinx resolution, and (3) scoliosis progression.ResultsAt this time, there is no level I or IIa evidence comparing PFD with PFDD. The notions that PFDD has a lower rate of reoperation and that PFD has a lower rate of cerebrospinal fluid-related complications are both based on IIb/B evidence.ConclusionsProspective randomized trials are necessary for definitive comments regarding the success of PFD and PFDD.

Transnasal odontoid resection followed by posterior decompression and occipitocervical fusion in children with Chiari malformation Type I and ventral brainstem compression.

OBJECT In rare cases, children with a Chiari malformation Type I (CM-I) suffer from concomitant, irreducible, ventral brainstem compression that may result in cranial neuropathies or brainstem dysfunction. In these circumstances, a 360 degrees decompression supplemented by posterior stabilization and fusion is required. In this report, the authors present the first experience with using an endoscopic transnasal corridor to accomplish ventral decompression in children with CM-I that is complicated by ventral brainstem compression. METHODS Two children presented with a combination of occipital headaches, swallowing dysfunction, myelopathy, and/or progressive scoliosis. Imaging studies demonstrated CM-I with severely retroflexed odontoid processes and ventral brainstem compression. Both patients underwent an endoscopic transnasal approach for ventral decompression, followed by posterior decompression, expansive duraplasty, and occipital-cervical fusion. RESULTS In both patients the endoscopic transnasal approach provided excellent ventral access to decompress the brainstem. When compared with the transoral approach, endoscopic transnasal access presents 4 potential advantages: 1) excellent prevertebral exposure in patients with small oral cavities; 2) a surgical corridor located above the hard palate to decompress rostral pathological entities more easily; 3) avoidance of the oral trauma and edema that follows oral retractor placement; and 4) avoidance of splitting the soft or hard palate in patients with oral-palatal dysfunction from ventral brainstem compression. CONCLUSIONS The endoscopic transnasal approach is atraumatic to the oral cavity, and offers a more superior region of exposure when compared with the standard transoral approach. Depending on their comfort level with endoscopic surgical techniques, pediatric neurosurgeons should consider this approach in children with pathological entities requiring ventral brainstem decompression.

Magnetic Resonance Imaging Characteristics of Glioblastoma Multiforme: Implications for Understanding Glioma Ontogeny

BACKGROUND:Identifying the origin of gliomas carries important implications for advancing the treatment of these recalcitrant tumors. Recent research promotes the hypothesis of a subventricular zone (SVZ) origin for the stemlike gliomagenic cells identified within human glioma specimens. However, conflicting evidence suggests that SVZ-like cells are not uniquely gliomagenic but this capacity may be shared by cycling progenitors distributed throughout the subcortical white matter (SCWM). OBJECTIVE:To review radiological evidence in glioblastoma multiforme (GBM) patients to provide insight into the question of glioma ontogeny. METHODS:We explored whether GBMs at first diagnosis demonstrated a pattern of anatomic distribution consistent with origin at the SVZ through retrospective analysis of preoperative contrast-enhanced T1-weighted magnetic resonance images in 63 patients. We then examined the relationship of tumor volume, point of origin, and proximity to the ventricles using a computer model of glioma growth. RESULTS:Fewer than half of the GBMs analyzed had contrast-enhancing portions that contacted the ventricle on preoperative imaging. A strong correlation was found between tumor volume and the distance between the contrast-enhancing edge of the tumor and the ventricle, demonstrating that tumors abutting the ventricle are significantly larger than those that do not. The lesions simulated by the computer model validated our assumption that tumors that are radiographically distant from the ventricles are unlikely to have originated in the SVZ and supported our hypothesis that as they grow, the edges of all tumors will near the ventricles, regardless of their point of origin. CONCLUSION:This work offers further support for the hypothesis that the origins of GBMs are at sites distributed throughout the white matter and are not limited to the region of the SVZ.

Molecular sub-group-specific immunophenotypic changes are associated with outcome in recurrent posterior fossa ependymoma.

Better understanding of ependymoma (EPN) biology at relapse is needed to improve therapy at this critical event. Convincing data exist defining transcriptionally distinct posterior fossa (PF) sub-groups A and B at diagnosis. The clinical and biological consequence of these sub-groups at recurrence has not yet been defined. Genome and transcriptome microarray profiles and clinical variables of matched primary and first recurrent PF EPN pairs were used to identify biologically distinct patterns of progression between EPN sub-groups at recurrence. Key findings were validated by histology and immune function assays. Transcriptomic profiles were partially conserved at recurrence. However, 4 of 14 paired samples changed sub-groups at recurrence, and significant sub-group-specific transcriptomic changes between primary and recurrent tumors were identified, which were predominantly immune-related. Further examination revealed that Group A primary tumors harbor an immune gene signature and cellular functionality consistent with an immunosuppressive phenotype associated with tissue remodeling and wound healing. Conversely, Group B tumors develop an adaptive, antigen-specific immune response signature and increased T-cell infiltration at recurrence. Clinical distinctions between sub-groups become more apparent after first recurrence. Group A tumors were more often sub-totally resected and had a significantly shorter time to subsequent progression and worse overall survival. Minimal tumor-specific genomic changes were observed for either PF Groups A or B at recurrence. Molecular sub-groups of PF EPN convey distinct immunobiologic signatures at diagnosis and recurrence, providing potential biologic rationale to their disparate clinical outcomes. Immunotherapeutic approaches may be warranted, particularly in Group A PF EPN.

Craniovertebral junction abnormalities in Down syndrome.

Children with Down syndrome may have occipitocervical and atlantoaxial instability. To prevent neurologic injury during athletic competitions, such as the Special Olympics, radiographic cervical spine screening was established in 1983 as a prerequisite for participation in some events. This review discusses the biomechanics underlying upper cervical instability in children with Down syndrome, the evolution of cervical spine screening protocols, and current opinion regarding management for children with Down syndrome and upper cervical instability.CHILDREN WITH DOWN syndrome may have occipitocervical and atlantoaxial instability. To prevent neurologic injury during athletic competitions, such as the Special Olympics, radiographic cervical spine screening was established in 1983 as a prerequisite for participation in some events. This review discusses the biomechanics underlying upper cervical instability in children with Down syndrome, the evolution of cervical spine screening protocols, and current opinion regarding management for children with Down syndrome and upper cervical instability.

Equivalence of fusion rates after rigid internal fixation of the occiput to C-2 with or without C-1 instrumentation

OBJECT The object of this study was to assess a multiinstitutional experience with pediatric occipitocervical constructs to determine whether a difference exists between the fusion and complication rates of constructs with or without direct C-1 instrumentation. METHODS Seventy-seven cases of occiput-C2 instrumentation and fusion, performed at 9 childrens hospitals, were retrospectively analyzed. Entry criteria included atlantooccipital instability with or without atlantoaxial instability. Any case involving subaxial instability was excluded. Constructs were divided into 3 groups based on the characteristics of the anchoring spinal instrumentation: Group 1, C-2 instrumentation; Group 2, C-1 and C-2 instrumentation without transarticular screw (TAS) placement; and Group 3, any TAS placement. Groups were compared based on rates of fusion and perioperative complications. RESULTS Group 1 consisted of 16 patients (20.8%) and had a 100% rate of radiographically demonstrated fusion. Group 2 included 22 patients (28.6%), and a 100% fusion rate was achieved, although 2 cases were lost to follow-up before documented fusion. Group 3 included 39 patients (50.6%) and demonstrated a 100% radiographic fusion rate. Complication rates were 12.5, 13.7, and 5.1%, respectively. There were 3 vertebral artery injuries, 1 (4.5%) in Group 2 and 2 (5.1%) in Group 3. CONCLUSIONS High fusion rates and low complication rates were achieved with each configuration examined. There was no difference in fusion rates between the group without (Group 1) and those with (Groups 2 and 3) C-1 instrumentation. These findings indicated that in the pediatric population, excellent occipitocervical fusion rates can be accomplished without directly instrumenting C-1.

Pediatric Low-Grade Ganglioglioma: Epidemiology, Treatments, and Outcome Analysis on 348 Children From the Surveillance, Epidemiology, and End Results Database

BACKGROUND Low-grade gangliogliomas/gangliocytomas (GGs) are rare tumors of the central nervous system that occur mostly in young people. Because of their rarity, large-scale, population-based studies focusing on epidemiology and outcomes are lacking. OBJECTIVE To use the Surveillance, Epidemiology, and End Results (SEER) data sets of the National Cancer Institute to study demographics, tumor location, initial treatment, and outcome data on low-grade GGs in children. METHODS SEER-STAT v8.1.2 identified all patients aged 0 to 19 years in the SEER data sets with low-grade GGs. Using the Kaplan-Meier method and Cox proportional hazard regression, we examined associations between these characteristics and survival. RESULTS There were 348 children with low-grade GGs diagnosed from 2004 to 2010, with a median follow-up of 37 months. Tumors were more prevalent in males (n = 208, 59.8%) than females (n = 140, 40.2%) (P < .001). Almost 63% occurred in children >10 years, whereas only 3.5% were found in those <1 year old. Approximately 50% were located in the temporal lobes, and only 3.7% and 3.5% were located in the brainstem and spinal cord, respectively. Surgery was performed on 91.6% of cases, with gross total resection achieved in 68.3%. Radiation was used in 3.2%. Young age (<1 year) and brainstem location were associated with worse overall survival. CONCLUSION This study shows that low-grade GGs occur in older children with a male preference. Gross total resection is achieved in the majority of cases, and radiation is rarely used. Although the majority of patients have an excellent prognosis, infants and patients with brainstem tumors have worse survival rates.

Surgical treatment of single-suture craniosynostosis: an argument for quantitative methods to evaluate cosmetic outcomes

The traditional reasons for surgical intervention in children with single-suture craniosynostosis (SSC) are cosmetic improvement and the avoidance/treatment of intracranial hypertension, which has been thought to contribute to neurocognitive deficits. Despite considerable work on the topic, the exact prevalence of intracranial hypertension in the population of patients with SSC is unknown, although it appears to be present in only a minority. Additionally, recent neuropsychological and anatomical literature suggests that the subtle neurocognitive deficits identified in children with a history of SSC may not result from external compression. They may instead reflect an underlying developmental condition that includes disordered primary CNS development and early suture fusion. This implies that current surgical techniques are unlikely to prevent neurocognitive deficits in patients with SSC. As such, the most common indication for surgical treatment in SSC is cosmetic, and most patients benefit from considerable subjective cosmetic normalization following surgery. Pediatric craniofacial surgeons have not, however, agreed upon objective means to assess postoperative cranial morphological improvement. We should therefore endeavor to agree upon objective craniometric tools for the assessment of operative outcomes, allowing us to accurately compare the various surgical techniques that are currently available.

Atypical teratoid/rhabdoid tumor arising in a ganglioglioma: genetic characterization.

Atypical teratoid/rhabdoid tumor (AT/RT) is an uncommon, aggressive, embryonal pediatric brain tumor that almost always develops de novo and does not arise within, or evolve from, other brain tumor types. Although rhabdoid morphology can be seen in other tumor types, these are phenotypic mimics and, with only rare exceptions, do not manifest the INI-1 deletion at the 22q11.2 locus or the INI-1 nuclear protein loss that characterizes AT/RT. A few reports of AT/RT evolving from a low-grade ganglioglioma (GG) or pleomorphic xanthoastrocytoma have appeared. We present the case of a 6-year-old boy with a large right parietal mass whose tumor at initial presentation manifested 2 distinct components: GG with neoplastic neurons, low MIB-1 rate, and retention of INI-1 nuclear immunostaining (immunohistochemical) and, second, AT/RT with rhabdoid cells, polyphenotypic immunohistochemical expression, high MIB-1 rate, and loss of INI-1 nuclear expression. The 2 areas were separately assessed by fluorescence in situ hybridization for monosomy 22; monosomy 22 was identified in the AT/RT component but not in the GG areas. BRAF V600E mutation, a genetic abnormality seen in a significant percentage of pleomorphic xanthoastrocytomas and GGs, was assessed by polymerase chain reaction and identified in the tumor. Dual abnormalities of INI-1 loss and V600E BRAF mutation were identified in a cell culture line established from cerebrospinal fluid metastatic tumor cells. This cell line exhibited extremely rapid growth rate and rhabdoid morphology. Results suggest a postclonal modification in a subset of GG cells, with acquisition of INI-1 loss, confirming by biological methods what was previously suspected in rare reports of AT/RT evolving from other tumor types.