Occipitoatlantoaxial rotatory fixation (OAARF) is a rare condition involving fixed rotational subluxation of the atlas in relation to both the occiput and axis. Atlantoaxial rotatory fixation (AARF) appears to precede OAARF in most cases, as untreated AARF may cause compensatory counter-rotation and occipitoaxial fixation at an apparently neutral head position. We report a case of OAARF in an 8-year-old girl with juvenile idiopathic arthritis. Cervical imaging demonstrated slight rightward rotation of the occiput at 7.63° in relation to C-2 and significant rightward rotation of C-1 at 65.90° in relation to the occiput and at 73.53° in relation to C-2. An attempt at closed reduction with halo traction was unsuccessful. Definitive treatment included open reduction, C-1 laminectomy, and occipitocervical internal fixation and fusion.
Matthew R. Fusco, Todd C. Hankinson, and Curtis J. Rozzelle
Astrid C. Hengartner, Eric Prince, Trinka Vijmasi, and Todd C. Hankinson
The evolving characterization of the biological basis of adamantinomatous craniopharyngioma (ACP) has provided insights critical for novel systemically delivered therapies. While current treatment strategies for ACP are associated with low mortality rates, patients experience severely lowered quality of life due to high recurrence rates and chronic sequelae, presenting a need for novel effective treatment regimens. The identification of various dysregulated pathways that play roles in the pathogenesis of ACP has prompted the investigation of novel treatment options. Aberrations in the CTNNB1 gene lead to the dysregulation of the Wnt pathway and the accumulation of nuclear β-catenin, which may play a role in tumor invasiveness. While Wnt pathway/β-catenin inhibition may be a promising treatment for ACP, potential off-target effects have limited its use in current intervention strategies. Promising evidence of the therapeutic potential of cystic proinflammatory mediators and immunosuppressants has been translated into clinical therapies, including interleukin 6 and IDO-1 inhibition. The dysregulation of the pathways of mitogen-activated protein kinase/extracellular signal–regulated kinase (MAPK/ERK), epidermal growth factor receptor (EGFR), and programmed cell death protein 1 and its ligand (PD-1/PD-L1) has led to identification of various therapeutic targets that have shown promise as clinical strategies. The Sonic Hedgehog (SHH) pathway is upregulated in ACP and has been implicated in tumorigenesis and tumor growth; however, inhibition of SHH in murine models decreased survival, limiting its therapeutic application. While further preclinical and clinical data are needed, systemically delivered therapies could delay or replace the need for more aggressive definitive treatments. Ongoing preclinical investigations and clinical trials of these prospective pathways promise to advance treatment approaches aimed to increase patients’ quality of life.
Leslie C. Robinson, Sandro Santagata, and Todd C. Hankinson
The recent genomic and transcriptomic characterization of human craniopharyngiomas has provided important insights into the pathogenesis of these tumors and supports that these tumor types are distinct entities. Critically, the insights provided by these data offer the potential for the introduction of novel therapies and surgical treatment paradigms for these tumors, which are associated with high morbidity rates and morbid conditions. Mutations in the CTNNB1 gene are primary drivers of adamantinomatous craniopharyngioma (ACP) and lead to the accumulation of β-catenin protein in a subset of the nuclei within the neoplastic epithelium of these tumors. Dysregulation of epidermal growth factor receptor (EGFR) and of sonic hedgehog (SHH) signaling in ACP suggest that paracrine oncogenic mechanisms may underlie ACP growth and implicate these signaling pathways as potential targets for therapeutic intervention using directed therapies. Recent work shows that ACP cells have primary cilia, further supporting the potential importance of SHH signaling in the pathogenesis of these tumors. While further preclinical data are needed, directed therapies could defer, or replace, the need for radiation therapy and/or allow for less aggressive surgical interventions. Furthermore, the prospect for reliable control of cystic disease without the need for surgery now exists. Studies of papillary craniopharyngioma (PCP) are more clinically advanced than those for ACP. The vast majority of PCPs harbor the BRAF v600e mutation. There are now 2 reports of patients with PCP that had dramatic therapeutic responses to targeted agents. Ongoing clinical and research studies promise to not only advance our understanding of these challenging tumors but to offer new approaches for patient management.
Monica Salazar Davern, Sumeet Garg, and Todd C. Hankinson
This report describes the presentation and operative treatment of a 3-year-old boy who survived a motor vehicle accident that resulted in a C6–7 distraction injury, complete avulsion of the spinal cord, and gross spinal instability. Only 5%–10% of all spinal cord and vertebral column injuries occur in children. Survival after such an injury is exceptionally rare in very young patients and is associated with severe neurological deficits. The authors discuss the substantial ethical challenges involved in the care of a patient with this injury. To their knowledge, only two other cases of survival have been reported in pediatric patients following motor vehicle trauma resulting in complete injury to the lower cervical spinal cord.
Todd C. Hankinson, J Mocco, Brent Kimball, Richard C. E. Anderson, and Neil A. Feldstein
✓The authors describe the internal cranial expansion (ICE) procedure, a surgical technique that was used to treat two chronically shunt-treated children who presented with medically and surgically refractory intracranial hypertension despite the presence of functioning cerebrospinal fluid shunt systems. The ICE procedure was used as a means to increase intracranial volume without sacrificing calvarial rigidity. Intracranial volume was increased by 5% in one case and 10% in the other. Both patients have returned to their neurological and functional baselines, and they are free of symptoms related to intracranial hypertension.
R. Michael Scott
Omar N. Syed, Todd C. Hankinson, William J. Mack, Neil A. Feldstein, and Richard C. E. Anderson
Pediatric neurosurgeons frequently care for children with traumatic scalp and skull injury. Foreign objects are often observed on imaging and may influence the clinician's decision-making process. The authors report on 2 cases of poorly visualized hair beads that had become embedded into the skull during blunt trauma. In both cases, skull radiography and CT scanning demonstrated depressed, comminuted fractures with poorly demonstrated spherical radiolucencies in the overlying scalp. The nature of these objects was initially unclear, and they could have represented air that entered the scalp during trauma. In one case, scalp inspection demonstrated no evidence of the bead. In the other case, a second bead was observed at the site of scalp laceration. In both cases, the beads were surgically removed, the fractures were elevated, and the patients recovered uneventfully. Radiolucent fashion accessories, such as hair beads, may be difficult to appreciate on clinical examination and may masquerade as clinically insignificant air following cranial trauma. If they are not removed, these foreign bodies may pose the risk of an infection. Pediatric neurosurgeons should consider hair accessories in the differential diagnosis of foreign bodies that may produce skull fracture following blunt trauma.
Todd C. Hankinson, Elizabeth J. Fontana, Richard C. E. Anderson, and Neil A. Feldstein
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.
Todd C. Hankinson, Elizabeth J. Campagna, Nicholas K. Foreman, and Michael H. Handler
The current management paradigm for children with newly diagnosed diffuse intrinsic pontine glioma (DIPG) is to establish a diagnosis and begin therapy based on MR imaging findings correlated with an appropriate clinical presentation, and without a tissue diagnosis. This strategy assumes that pediatric neurosurgeons and neurooncologists uniformly interpret MR imaging findings in this population. This study sought to examine the consistency of North American pediatric neurosurgeons in assessing MR images in this patient population, and in their surgical plans based on the interpretation of those images.
The authors created an online survey and invited all members of the American Society of Pediatric Neurosurgeons and the American Association of Neurological Surgeons/Congress of Neurological Surgeons Joint Section for Pediatric Neurosurgery to participate. The survey consisted of 58 questions, and 48 pertained to representative MR images from 16 children who presented to The Children's Hospital of Colorado with diffuse pontine tumors. Based on the imaging presented and a standard clinical scenario, the respondent was asked if she or he believed a lesion to be “typical” or “atypical,” whether she or he would biopsy the lesion, and what surgical approach would be chosen. The remaining 10 questions pertained to respondent demographics and his or her practice regarding tissue preservation and interest in participating in a multicenter trial that included tumor biopsy in selected cases. Rates at which each lesion was considered to be typical or atypical and rates of recommended biopsy were calculated.
Surveys were received by 269 individuals. Eighty-six responses were received (32.0%). No tumor was judged to be either typical or atypical by all respondents. Individual surgeons varied widely regarding how many of the tumors were judged as typical or warranted a biopsy. The percentage of respondents who disagreed with the majority opinion regarding whether a tumor qualified as typical ranged from 2.3% to 48.8%, with a median of 28.6%. More than 75% agreement regarding whether a tumor was typical or atypical was found in 7 (43.8%) of 16 cases. The κ statistic regarding typicality was 0.297 ± 0.0004 (mean ± SEM), implying only fair agreement. For every tumor, at least 1 respondent who believed the lesion to be typical in appearance would nevertheless biopsy the lesion. Of those respondents who considered a lesion to be typical, a median of 5.1% (range 1.2%–66.7%) would choose to biopsy this lesion. Of those respondents who considered a lesion atypical, a median of 18.3% (range 3.7%–100%) would choose not to biopsy the lesion. Of 85 responses to the question, “Would you be willing to biopsy a typical diffuse pontine glioma as a part of a multicenter trial?,” 59 (69.4%) of 85 respondents answered that they would.
Although making a diagnosis based on radiographic evidence alone represents a well-established management paradigm for children with suspected DIPG, this study demonstrates considerable inconsistency on the part of pediatric neurosurgeons in the application of this strategy to individual patients. As such, the practice of diagnosing DIPG based on imaging characteristics and clinical history alone does not reach the appropriate threshold to be considered a standard of care.
Brent R. O'Neill, Danielle Gallegos, Alex Herron, Claire Palmer, Nicholas V. Stence, Todd C. Hankinson, C. Corbett Wilkinson, and Michael H. Handler
Cutaneous stigmata or congenital anomalies often prompt screening for occult spinal dysraphism (OSD) in asymptomatic infants. While a number of studies have examined the results of ultrasonography (US) screening, less is known about the findings when MRI is used as the primary imaging modality. The object of this study was to assess the results of MRI screening for OSD in infants.
The authors undertook a retrospective review of all infants who had undergone MRI of the lumbar spine to screen for OSD over a 6-year period (September 2006–September 2012). All images had been obtained on modern MRI scanners using sequences optimized to detect OSD, which was defined as any fibrolipoma of the filum terminale (FFT), a conus medullaris ending at or below the L2–3 disc space, as well as more complex lesions such as lipomyelomeningocele (LMM).
Five hundred twenty-two patients with a mean age of 6.2 months at imaging were included in the study. Indications for imaging included isolated dimple in 235 patients (45%), asymmetrically deviated gluteal cleft in 43 (8%), symmetrically deviated (Y-shaped) gluteal cleft in 38 (7%), hemangioma in 28 (5%), other isolated cutaneous stigmata (subcutaneous lipoma, vestigial tail, hairy patch, and dysplastic skin) in 31 (6%), several of the above stigmata in 97 (18%), and congenital anomalies in 50 (10%).
Twenty-three percent (122 patients) of the study population had OSD. Lesions in 19% of these 122 patients were complex OSD consisting of LMM, dermal sinus tract extending to the thecal sac, and lipomeningocele. The majority of OSD lesions (99 patients [81%]) were filar abnormalities, a group including FFT and low-lying conus.
The rate of OSD ranged from 12% for patients with asymmetrically deviated gluteal crease to 55% for those with other isolated cutaneous stigmata.
Isolated midline dimple was the most common indication for imaging. Among this group, 20% (46 of 235) had OSD. There was no difference in the rate of OSD based on dimple location. Those with OSD had a mean dimple position of 15 mm (SD 11.8) above the coccyx. Those without OSD had a mean dimple position of 12.2 mm (SD 19) above the coccyx (p = 0.25).
The prevalence of OSD identified with modern high-resolution MRI screening is significantly higher than that reported with US screening, particularly in patients with dimples. The majority of OSD lesions identified are FFT and low conus. The clinical significance of such lesions remains unclear.