Review Article: Chiari Type I Malformation with or Without Syringomyelia: Prevalence and Genetics

The Genetics of Chiari 1 Malformation

Chiari malformation type 1 (CM1) is a structural defect that involves the herniation of the cerebellar tonsils through the foramen magnum, causing mild to severe neurological symptoms. Little is known about the molecular and developmental mechanisms leading to its pathogenesis, prompting current efforts to elucidate genetic drivers. Inherited genetic disorders are reported in 2-3% of CM1 patients; however, CM1, including familial forms, is predominantly non-syndromic. Recent work has focused on identifying CM1-asscoiated variants through the study of both familial cases and de novo mutations using exome sequencing. This article aims to review the current understanding of the genetics of CM1. We discuss three broad classes of CM1 based on anatomy and link them with genetic lesions, including posterior fossa-linked, macrocephaly-linked, and connective tissue disorder-linked CM1. Although the genetics of CM1 are only beginning to be understood, we anticipate that additional studies with diverse patient populations, tissue types, and profiling technologies will reveal new insights in the coming years.

YouTube as a Tool for Medical Education: Analyzing Content Quality and Reliability on Chiari Malformation

BACKGROUND

Chiari malformation is a structural defect in the brain, affecting the cerebellum, brainstem, upper cervical cord, and cranial base, with severe cases involving herniation through the foramen magnum. This condition can significantly impact the patient's quality of life. Given the elective nature of surgical treatment for Chiari 1 malformations, many patients seek supplemental information on YouTube. This study aimed to evaluate the quality, accuracy, reliability, and educational value of YouTube videos on Chiari malformation decompression surgery.

METHODS

We selected 77 videos for analysis based on specific criteria such as language, duration, and minimum view count. The selected videos were scored using modified DISCERN, Global Quality Score, and Journal of the American Medical Association criteria. Data regarding the video content and creators were collected. Statistical analysis was performed using the Kolmogorov-Smirnov test to assess data normality and the Mann-Whitney U test to determine statistical significance.

RESULTS

The overall quality and reliability of YouTube videos on Chiari malformation decompression surgery were found to be moderate. Videos longer than 5 minutes and those featuring a physician had significantly higher scores across all metrics.

CONCLUSIONS

This study highlights the need for improved regulation and the promotion of high-quality medical content on online platforms. Healthcare providers should guide patients toward reliable resources and consider collaborating with content creators to enhance the quality of educational materials available online. Improved oversight and quality control on platforms like YouTube can better support patient education and clinical decision-making.

Paragangliomas and syringomyelia in Tetralogy of Fallot-A case report and literature review

Pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries, paragangliomas, and syringomyelia are uncommon diseases. Furthermore, in the absence of any genetic link and with less than five reported adult patients surviving unrepaired rare form of Tetralogy of Fallot, our case shows noteworthiness. The possibility of definitive treatment of these conditions is rendered unsafe due to this persistent defect. Thus, management and ongoing survival of this patient remains complex and challenging.

Posterior Cranial Vault Distractor Osteogenesis for the Treatment of Chiari Malformation Type 1: A Systematic Review of the Literature

BACKGROUND

Although posterior cranial vault distraction osteogenesis (PVDO) is utilized routinely now for the treatment of craniosynostosis, its use as a treatment option for Chiari type 1 malformation (CM1) is limited to case reports and small retrospective case series.

METHODS

The authors conducted a systematic review of the published literature for PVDO as a treatment for CM1. The primary outcomes were reported complications, symptom improvement, and reoperation rates in patients that had PVDO surgery for CM1. The authors further investigated differences between patients with CM1 with an associated genetic syndrome and craniosynostosis.

RESULTS

In total, 42 patients with an average age of 41.1 months were used in our analysis. A total of 38.1% of the patients had a diagnosed syndrome, 78.6% of patients had associated craniosynostosis, and 26/42 (61.9%) total patients-reported symptom improvement. Of 26 patients that reported symptom improvement, 20 (76.9%) had associated syndromes and 6 (23.1%) did not (P=0.011). In addition, of these 26 symptom improved patients, 17 (65.4%) were associated with craniosynostosis while 9 (36.4%) did not have craniosynostosis (P=0.008).

CONCLUSIONS

Posterior cranial vault distraction osteogenesis seems to be a promising new surgical intervention for treatment of CM1. Most patients saw symptom improvement after treatment (61.9%). There was a clinically and statistically significant difference in symptom improvement for patients with syndromic CM1 when compared with nonsyndromic CM1 patients.

Multi-Dimensional Morphometric and Volumetric Analysis of the Posterior Cranial Fossa to Study Type I Chiari Malformation

BACKGROUND

Chiari malformation type I (CM-1) is a complex disorder in which tonsillar herniation through the foramen magnum (FM) manifests with a spectrum of clinical symptoms. This work analyzes morphometric and volumetric characteristics of CM-1 patients.

METHODS

With institutional review board approval, we retrospectively reviewed a total of 72 adult CM-1 patients and 26 healthy adult volunteers who underwent volumetric magnetic resonance brain imaging. Clinical data were retrospectively extracted from the electronic medical record. We analyzed multidimensional morphometric and volumetric features within the posterior cranial fossa and correlated these features with syrinx formation and the decision to undergo surgical decompression.

RESULTS

In our study, CM-1 patients had decreased cerebellar (CBL), brainstem, and fourth ventricular volumes but larger tonsillar volume with increased total tonsillar length. CM-1 patients who underwent surgery had significantly more neural tissue within the cross-sectional area of the cisterna magna. Logistic regression demonstrated that combining neural tissue at the FM with CBL and fourth ventricular volumes led to a great degree of correlation with syrinx formation (area under the curve: 0.911).

CONCLUSIONS

Our findings suggest that the amount of tissue at the FM correlates with CM-1 patients who underwent decompressive surgery, more so than tonsillar length. Additionally, the combination of neural tissue at the FM, CBL, and fourth ventricular volumes led to a great degree of correlation with syrinx formation. Together, these findings suggest that a global compressive phenomenon within the posterior fossa leads to CM-1 symptomatology and syrinx formation.

Exploring pathogenesis, prevalence, and genetic associations in Chiari malformation type 1: a contemporary perspective

Chiari malformation type 1 (CM 1) entails a structural defect in the cerebellum, involving the herniation of cerebellar tonsils toward the foramen magnum. The symptomatic or asymptomatic nature of CM 1 is contingent upon the condition of malformation in the spinal cord. This review presents an updated perspective on the prevalence of CM 1, its pathogenesis, genetic associations, and treatment. CM 1 exhibits a higher prevalence in adult females than males. Despite the incomplete understanding of the exact cause of CM 1, recent research suggests the involvement of both genetic and environmental factors in its development. One of the reasons for the occurrence of CM 1 in individuals is the smaller posterior cranial fossa, which manifests as typical morphological features. Additionally, environmental factors can potentially interact with genetic factors, modifying the observable characteristics of the disease and affecting the symptoms, severity, and development of the condition. Notably, headaches, neck pain, dizziness, and neurological deficits may be exhibited by individuals with CM 1, highlighting the importance of early diagnosis. Magnetic resonance imaging (MRI) serves as an alternative diagnostic technique for monitoring the symptoms of CM 1. Multiple genetic factors are likely to contribute to a cascade of abnormalities in CM 1. Early studies provided evidence, including clustering within families, bone development, and co-segregation with known genetic syndromes, establishing CM 1's association with a genetic basis. Furthermore, surgery is the only available treatment option to alleviate symptoms or hinder the progression of damage to the central nervous system (CNS) in CM 1 cases.

Type one chiari malformation as a cause of central sleep apnea and hypoventilation in children

OBJECTIVES

Chiari type 1 malformation (CM1) may occasionally lead to central sleep apnea (CSA). We studied, in a large clinical cohort of pediatric CM1 patients, the effect of CM1 on breathing during sleep.

METHODS

This is a retrospective single pediatric pulmonology center study with a systematic evaluation of pediatric CM1 patients under age 18 with polysomnography (PSG) during 2008-2020. Children with syndromes were excluded. All patients had undergone head and spine magnetic resonance imaging.

RESULTS

We included 104 children with CM1 with a median age of 7 (interquartile range (IQR) 5-13) years. The median extent of tonsillar descent (TD) was 13 (IQR 10-18) mm. Syringomyelia was present in 19 children (18%). Of all children, 53 (51%) had normal PSG, 35 (34%) showed periodic breathing or central apnea and hypopnea index ≥5 h-1, and 16 (15%) displayed features of compensated central hypoventilation and end-tidal or transcutaneous carbon dioxide 99th percentile level above 50 mmHg. TD had the best predictive value for central breathing disorders. In a linear model, both age (61%) and TD (39%) predicted median breathing frequency (R = 0.33, p < 0.001).

CONCLUSIONS

Although severe CSA is a rare complication of brainstem compression in pediatric patients with CM1, short arousal-triggered episodes of periodic breathing and mild compensated central hypoventilation are common. TD shows the best but still poor prediction of the presence of a central breathing disorder. This highlights the use of PSG in patient evaluation. Posterior fossa decompression surgery effectively treats central breathing disorders.

A Pragmatic Neuro-Rehabilitation Approach for Basilar Invagination: A Case Report

Basilar invagination is a rare pathology of the occipital bone, along with prolapsing of the vertebral column. It is a narrowing in the opening of the foramen magnum of the odontoid process. It is a well-known cause of pain and tingling in the upper limbs. However, only a few afflictions requiring physiotherapy rehabilitation in basilar invaginations have been reported. Thus, this study was carried out to investigate a case of basilar invagination. A 51-year-old female visited the neuro-outpatient department. The chief complaints of the patient were restricted overhead activities, restricted neck and shoulder movements, upper limb weakness, and tingling of bilateral upper limbs for the past two months. Clinical examination revealed pain thresholds for the neck and shoulder at nine by ten on activity and five by ten on rest. Manual muscle testing revealed a significant reduction in the strength of muscles around the neck and shoulder at three by five on bilateral upper limbs. The patient was advised to have computed tomography (CT), magnetic resonance imaging (MRI), and a bone density test to confirm the diagnosis of the condition. Investigations revealed a case of basilar invagination. But due to the financial burden, surgery couldn't be opted for; therefore, she opted for physiotherapy rehabilitation. The patient was managed with neuro-physiotherapy rehabilitation exercises like neural tissue stretch, which included nerve gliding and nerve stretching exercises, vestibular rehabilitation exercises, and gaze stabilization exercises. The strengthening of weakened muscles was done using Delorme's technique. Cervical traction, electrotherapy, and moist heat modalities like interferential therapy and hydrocollator packs were given. It also included deep breathing exercises like diaphragmatic breathing and thoracic expansion exercises. The exercise was planned according to the frequency, intensity, time, and type (FITT) principle. Frequency: five days/week; intensity: slow to moderate pace with rest intervals; time: 60 minutes/day; type of exercise: strength training along with other exercises for a total of thirty days. The patient was able to resume her job after receiving physiotherapy rehabilitation, which played a pivotal role in decreasing her symptoms.

The Chiari Malformations: A Bibliometric Analysis of the 100 Most Cited Articles

OBJECTIVE

The Chiari malformations present heterogeneous entities, raising many questions regarding their natural history, pathophysiology, treatment options, and prognosis. Bibliometric analyses have emerged as a method to assess the impact of articles in current clinical practice.

METHODS

The most cited articles were identified via Scopus Library by using the keywords "Chiari," "Arnold-Chiari," and "Chiari malformation." The 100 most cited articles were then assembled and analyzed in detail.

RESULTS

The top 100 articles yielded a mean of 155,28 citations per article, ranging from 87 to 896 citations, and from 1.63 to 38.96 per year. Years of publications ranged from 1950 to 2015. Oakes was the most cited author (n = 7), followed by Tubbs and Milhorat. The country with the highest cited articles was the United States (n = 63), followed by the United Kingdom (n = 6), Italy (n = 5), Spain (n = 5), Japan (n = 4), and Germany (n = 3). Neurosurgery is the journal with the most highly cited articles (n = 21), followed by Journal of Neurosurgery (n = 19). Most articles focused on Chiari malformation type I (n = 83). The topic discussed most often was imaging (n = 63), followed by the evaluation of treatment outcome (n = 58), clinical signs and symptoms (n = 57), and the role of surgery (n = 56).

CONCLUSIONS

The present bibliometric analysis provides a succinct appraisal of the most cited articles concerning Chiari malformation, allowing a deeper insight in this area and its main influential articles with their impact on current clinical practice and future research.

Brain and eye involvement in McCune-Albright Syndrome: clinical and translational insights

McCune-Albright Syndrome (MAS) is a rare mosaic (post-zygotic) genetic disorder presenting with a broad continuum clinical spectrum. MAS arises from somatic, activating mutations in the GNAS gene, which induces a dysregulated Gsα-protein signaling in several tissues and an increased production of intracellular cyclic adenosine monophosphate (cAMP). Overall, MAS is a rare disorder affecting less than 1/100,000 children and, for this reason, data establishing genotype-phenotype correlations remain limited. Affected individuals clinically present with a variable combination of fibrous dysplasia of bone (FD), extra-skeletal manifestations (including cafeí-au-lait spots) and precocious puberty which might also be associated to broad hyperfunctioning endocrinopathies, and also gastrointestinal and cardiological involvement. Central nervous system (CNS) and eye involvement in MAS are among the less frequently described complications and remain largely uncharacterized. These rare complications mainly include neurodevelopmental abnormalities (e.g., delayed motor development, cognitive and language impairment), CNS anomalies (e.g., Chiari malformation type I) and a wide array of ophthalmological abnormalities often associated with vision loss. The pathophysiological mechanisms underlying abnormal neurological development have not been yet fully elucidated. The proposed mechanisms include a deleterious impact of chronically dysregulated Gsα-protein signaling on neurological function, or a secondary (damaging) effect of (antenatal and/or early postnatal) hypercortisolism on early pre- and post-natal CNS development. In this Review, we summarize the main neurological and ophthalmological features eventually associated with the MAS spectrum, also providing a detailed overview of the potential pathophysiological mechanisms underlying these clinical complications.

Cerebellar Tonsillar Descent Mimicking Chiari Malformation

Chiari I malformation has been defined as cerebellar tonsillar descent greater than 5 mm below the foramen magnum. Suboccipital decompression remains the mainstay of treatment for symptomatic patients. Other conditions sometimes have imaging features that mimic Chiari I malformation. These patients are at risk of misdiagnosis and mismanagement, including surgery that may be unnecessary or may even worsen the underlying condition. The aim of this study was to analyse a series of Chiari I malformation mimics and identify differentiating imaging features. The mimics are categorised as post-traumatic cranio-cervical junction arachnoiditis, dural band, spontaneous intracranial hypotension, idiopathic intracranial hypertension, and cysts. Better understanding of these conditions will assist with diagnosis and optimal management, including avoiding unnecessary surgery.

Audiovestibular Findings in a Cohort of Patients with Chiari Malformation Type I and Dizziness

Chiari Malformation Type I (CM1) is a neurological condition in which the cerebellar tonsils extend past the foramen magnum. While many studies have reported dizziness symptoms in patients with CM1, the prevalence of peripheral labyrinthine lesions is largely unknown. This study aimed to comprehensively describe the audiovestibular phenotype in a cohort of patients with CM1 expressly referred for dizziness. Twenty-four patients with CM1 and a complaint of dizziness/vertigo were evaluated. Hearing and auditory brainstem tract function were essentially normal. While vestibular abnormalities were most prevalent during rotational testing (33%), abnormal functional balance was the most common finding (40%). Patients with CM1 had a greater likelihood of exhibiting an abnormal sensory organization test (SOT) postural stability score for fixed platform conditions, and for the somatosensory analysis score. While no significant associations were identified between tonsillar ectopia extent and any vestibular/balance outcome measure, a significant negative association was identified between neck pain and the somatosensory sensory analysis score. Abnormal functional balance in the somatosensory domain was remarkable, with poorer scores associated with neck pain. An isolated peripheral vestibulopathy was present in only 8% of patients. Despite the low prevalence of vestibulopathy, vestibular/balance assessment is warranted to identify patients who may benefit from referral to specialized medical disciplines.

Recovery of diabetes insipidus after Chiari malformation decompression: A rare manifestation of Chiari malformation

This paper aims to introduce a patient with Chiari type 1 malformation presented with upper extremity pain and diabetes insipidus. After laboratory examinations, we confirmed our case's central diabetes insipidus diagnosis. The patient has undergone posterior fossa decompression, tonsilopexy, and duraplasty. After 6 months of follow-up, pain and diabetes insipidus were improved. We introduced a rare presentation of Chiari malformation in this article.

Headache characteristics and postoperative course in Chiari I malformation

Background

Chiari I malformation typically presents with cough headache. However, migraine-like or tension-type-like headaches may also occur. There are limited publications on Chiari I malformation-associated headache semiologies and the effect of foramen magnum decompression on different headache types.

Methods

A retrospective analysis complemented by structured phone interviews was performed on 65 patients with Chiari I malformation, treated at our hospital between 2010 and 2021. Headache semiology (according to ICHD-3), frequency, intensity, and radiological characteristics were evaluated pre- and postoperatively.

Results

We included 65 patients. 38 patients were female and 27 male. Mean age was 43.9 ± 15.7 years. Headache was predominant in 41 patients (63.0%). Twenty-one patients had cough headache and 20 had atypical headache (12 migrainous, eight tension-type headache-like). Thirty-five patients with headache underwent surgery. Frequency, intensity, and analgesic use was significantly reduced in cough headache (p < 0.001). Atypical headaches improved less (p = 0.004 to 0.176). Exploratory analysis suggested that larger preoperative tonsillar descent correlated with larger postoperative headache intensity relief (p = 0.025).

Conclusion

Decompression was effective in Chiari I malformation-related cough headache. Atypical headache responded less well, and the causal relation with Chiari I malformation remains uncertain. For atypical headache, decompression should only be considered after failed appropriate preventive therapy and within an interdisciplinary approach involving a neurologist.

On the association between Chiari malformation type 1, bone mineral density and bone related genes

Background

Chiari malformation type 1 (C1M) is a neurological disease characterized by herniation of the cerebellar tonsils below the foramen magnum. Cranial bone constriction is suspected to be its main cause. To date, genes related to bone development (e.g. DKK1 or COL1A2) have been associated with C1M, while some bone diseases (e.g. Paget) have been found to cosegregate with C1M. Nevertheless, the association between bone mineral density (BMD) and C1M has not been investigated, yet. Here, we systematically investigate the association between C1M and BMD, and between bone related genes and C1M.

Methods

We have recruited a small cohort of C1M patients (12 unrelated patients) in whom we have performed targeted sequencing of an in-house bone-related gene panel and BMD determination through non-invasive DXA.

Results

In the search for association between the bone related genes and C1M we have found variants in more than one C1M patient in WNT16, CRTAP, MYO7A and NOTCH2. These genes have been either associated with craniofacial development in different ways, or previously associated with C1M (MYO7A). Regarding the potential link between BMD and C1M, we have found three osteoporotic patients and one patient who had high BMD, very close to the HBM phenotype values, although most patients had normal BMD.

Conclusions

Variants in bone related genes have been repeatedly found in some C1M cases. The relationship of bone genes with C1M deserves further study, to get a clearer estimate of their contribution to its etiology. No direct correlation between BMD and C1M was observed.

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We used an in-house bone gene panel to investigate a small cohort of C1M patients.

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Variants in WNT16, CRTAP, MYO7A and NOTCH2 were found in more than one C1M patient.

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No clear relationship was found between C1M and BMD in this small C1M cohort.

Use of deep learning in the MRI diagnosis of Chiari malformation type I

Purpose

To train deep learning convolutional neural network (CNN) models for classification of clinically significant Chiari malformation type I (CM1) on MRI to assist clinicians in diagnosis and decision making.

Methods

A retrospective MRI dataset of patients diagnosed with CM1 and healthy individuals with normal brain MRIs from the period January 2010 to May 2020 was used to train ResNet50 and VGG19 CNN models to automatically classify images as CM1 or normal. A total of 101 patients diagnosed with CM1 requiring surgery and 111 patients with normal brain MRIs were included (median age 30 with an interquartile range of 23–43; 81 women with CM1). Isotropic volume transformation, image cropping, skull stripping, and data augmentation were employed to optimize model accuracy. K-fold cross validation was used to calculate sensitivity, specificity, and the area under receiver operating characteristic curve (AUC) for model evaluation.

Results

The VGG19 model with data augmentation achieved a sensitivity of 97.1% and a specificity of 97.4% with an AUC of 0.99. The ResNet50 model achieved a sensitivity of 94.0% and a specificity of 94.4% with an AUC of 0.98.

Conclusions

VGG19 and ResNet50 CNN models can be trained to automatically detect clinically significant CM1 on MRI with a high sensitivity and specificity. These models have the potential to be developed into clinical support tools in diagnosing CM1.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00234-022-02921-0.

"Motion-specific Headache": A Predictor for Diagnosis and Favorable Prognosis after Surgery in Young Patients with Chiari Malformation Type 1

As headache is known as one of the most common symptoms in the patients with Chiari malformation type 1 (CM1), it is difficult to find out CM1-related headache among the symptoms because headache itself is commonly seen. Herein, we retrospectively review the cases of six CM1 patients complaining only of headache by which they complained of deterioration in daily life activities. The symptom of headache worsened during anteflexion (n = 2; 33%), retroflexion (n = 1; 17%), jumping (n = 3; 50%), going up the stairs (n = 1; 17%), and running (n = 1; 17%). Mean age at the onset was 15.7 years old (ranging 11–18) and four out of six were female. These inductive factors were clearly different from “Valsalva-like maneuvers,” although the mechanism might originate from dynamic tonsil changes. We named these headaches as “motion-specific.” These headaches radiated to the posterior side. MRI revealed that the extent of tonsillar ectopia was 11.3 mm, while syringomyelia was observed in three out of six patients (50%). All patients underwent surgical treatment, with the “motion-specific headache” completely disappearing 12.5 days thereafter. Although headaches are common, “motion-specific headache” may be a good candidate symptom to distinguish CM1 patients, especially among teenagers with headaches, and a good predictor for favorable outcomes after surgical treatment.

Is there a morphometric cause of Chiari malformation type I? Analysis of existing literature

Although many etiologies have been proposed for Chiari malformation type I (CM-I), there currently is no singular known cause of CM-I pathogenesis. Advances in imaging have greatly progressed the study of CM-I. This study reviews the literature to determine if an anatomical cause for CM-I could be proposed from morphometric studies in adult CM-I patients. After conducting a literature search using relevant search terms, two authors screened abstracts for relevance. Full-length articles of primary morphometric studies published in peer-reviewed journals were included. Detailed information regarding methodology and symptomatology, craniocervical instability, syringomyelia, operative effects, and genetics were extracted. Forty-six studies met inclusion criteria, averaging 93.2 CM-I patients and 41.4 healthy controls in size. To obtain measurements, 40 studies utilized MRI and 10 utilized CT imaging, whereas 41 analyzed parameters within the posterior fossa and 20 analyzed parameters of the craniovertebral junction. The most commonly measured parameters included clivus length (n = 30), tonsillar position or descent (n = 28), McRae line length (n = 26), and supraocciput length (n = 26). While certain structural anomalies including reduced clivus length have been implicated in CM-I, there is a lack of consensus on how several other morphometric parameters may or may not contribute to its development. Heterogeneity in presentation with respect to the extent of tonsillar descent suggests alternate methods utilizing morphometric measurements that may help to identify CM-I patients and may benefit future research to better understand underlying pathophysiology and sequelae such as syringomyelia.

Interlayer dural split technique for Chiari I malformation treatment in adult-Technical note

OBJECTIVE

To present an alternative surgical technique in treating cases of Chiari I Malformation with mild-to-moderate syringomyelia after decompressive suboccipital craniectomy: incising only the outer layer of the dura mater, then dissecting it from the inner layer without opening the latter.

PATIENTS AND METHODS

We utilized this technique in a short series of three cases who were admitted to our department for mild symptoms such as intermittent headache and dissociated sensory loss in the upper limbs, caused by a Chiari Malformation Type I. The patients were placed in the sitting position. We performed a reduced median suboccipital craniectomy and resection of the posterior arch of C1 adapted to the level of tonsil descent, from a limited superior half to complete resection. Afterward, we incised the outer dural layer, while sparing the inner one. Using a fine dissector, we then split apart the outer and inner layers to the margin of the craniectomy. Through the transparency of the inner layer and the arachnoid, the cerebellum and the medulla were visible and pulsating. An autologous fascia duraplasty was then performed.

RESULTS

The postoperative course was favorable in all cases, the patients being discharged without any deficits and with complete symptom resolution. Follow-up at 3, 6, and 12 months after surgery revealed a significant reduction in brainstem compression and syringomyelia.

CONCLUSIONS

Interlayer dural split technique can be used effectively in treating symptomatic cases of type I Chiari malformation in adults, with mild-to-moderate syringomyelia. It is less invasive than opening the dura and possibly more effective than decompressive craniectomy and C1 laminectomy alone. This technique must be validated in a larger case-control series.

Long-term outcomes of surgical management in subtypes of Chiari malformation

Objective: Chiari malformations (CMs) are a heterogeneous group of disorders defined by anatomic anomalies of the cerebellum, brainstem, and craniovertebral junction (CVJ). The aims of this study are to establish the demographic and clinical features, incidence, surgical procedures, and outcomes in large series of old and new subtypes of CMs.Material and Methods: All patients were evaluated and operated on for CM-0, 1, and 1.5 between 1985 and 2016. The patients were grouped into various subtypes. Demographic data, additional diseases, clinical features, surgical procedures, complications and outcomes were recorded.Results: 191 patients who underwent various surgical procedures were evaluated. Their mean age was 37.21 ± 9.89. We detected 15 cases of CM-0 (7.8%), 121 cases of CM-1 (63.4%), 55 cases of CM-1.5 (28.8%). In total there were 191 cases, and 220 surgical procedures were performed. 29 (13.2%) of all surgical procedure was reoperations and secondary operations. SM Cyst is found to be decreased in 72 (76.5%) patients, unchanged in 14 (14.8%) and increased in 8(8.5%) of 94 patients radiologically. Clinical outcomes are better for 131 (65.8%), same for 31 (16.2%) and worse for 9 (15%).Conclusion: This study with 172 patients is a large series that includes CM-0, 1, and 1.5 subtypes. CM-1.5 also differs for symptom presentation and durations from CM-1. There are more neurological abnormalities in patients with SM. CVD alone are an effective, useful and safe surgical procedure for CM-0, CM-1 and CM-1.5. Surgical procedure, SM existence, and symptom duration have powerful effects on outcomes.

Arnold-Chiari Malformation and Scoliosis: A Chronic Lung Collapse Mimicking Sepsis

Scoliosis is a deformity of the spine caused by excessive lateral curvature. Compared to other variants, neuromuscular scoliosis is more likely to progress, altering the body's normal architecture in a relatively short period of time. Furthermore, patients with Arnold-Chiari malformation or Chiari malformation (CM) type 2 have intrinsic neurological complications that might entangle the initial clinical assessment. A 24-year-old woman with a history of scoliosis and CM type 2 status post-tracheostomy was admitted from a skilled nursing facility after a one-day history of low blood pressure, leukocytosis, and an outpatient chest X-ray suspicious for pneumonia. Physical examination was remarkable for hypotension and decreased breath sounds at the left pulmonary base. A tracheostomy tube and central venous catheter were noticed. Initial laboratory results revealed leukocytosis with borderline bandemia and a chest X-ray with a left lower lung consolidation. She was treated as a case of sepsis, for which broad-spectrum antibiotics were immediately started. However, upon review of charts, the patient's objective findings were similar to a previous admission. Chest computed tomography scan revealed atelectasis in the left lower lung with no signs of consolidation, effusions, or abscesses. After extensive workup, no identifiable cause was found to suggest an acute process. Antibiotic therapy was halted and the patient was discharged to her nursing home. This case presents a patient with CM type 2 and scoliosis complicated by chronic and worsening atelectasis. Accurate initial assessment and communication between providers are paramount to avoid overtreatment.

Rare functional genetic variants in COL7A1, COL6A5, COL1A2 and COL5A2 frequently occur in Chiari Malformation Type 1

Chiari Malformation Type 1 (CM-1) is characterized by herniation of the cerebellar tonsils below the foramen magnum and the presence of headaches and other neurologic symptoms. Cranial bone constriction is suspected to be the most common biologic mechanism leading to CM-1. However, other mechanisms may also contribute, particularly in the presence of connective tissue disorders (CTDs), such as Ehlers Danlos Syndrome (EDS). Accumulating data suggest CM-1 with connective tissue disorders (CTD+) may have a different patho-mechanism and different genetic risk factors than CM-1 without CTDs (CTD-). To identify CM-1 genetic risk variants, we performed whole exome sequencing on a single large, multiplex family from Spain and targeted sequencing on a cohort of 186 unrelated adult, Caucasian females with CM-1. Targeted sequencing captured the coding regions of 21 CM-1 and EDS candidate genes, including two genes identified in the Spanish family. Using gene burden analysis, we compared the frequency of rare, functional variants detected in CM-1 cases versus publically available ethnically-matched controls from gnomAD. A secondary analysis compared the presence of rare variants in these genes between CTD+ and CTD- CM-1 cases. In the Spanish family, rare variants co-segregated with CM-1 in COL6A5, ADGRB3 and DST. A variant in COL7A1 was present in affected and unaffected family members. In the targeted sequencing analysis, rare variants in six genes (COL7A1, COL5A2, COL6A5, COL1A2, VEGFB, FLT1) were significantly more frequent in CM-1 cases compared to public controls. In total, 47% of CM-1 cases presented with rare variants in at least one of the four significant collagen genes and 10% of cases harbored variants in multiple significant collagen genes. Moreover, 26% of CM-1 cases presented with rare variants in the COL6A5 gene. We also identified two genes (COL7A1, COL3A1) for which the burden of rare variants differed significantly between CTD+ and CTD- CM-1 cases. A higher percentage of CTD+ patients had variants in COL7A1 compared to CTD+ patients, while CTD+ patients had fewer rare variants in COL3A1 than did CTD- patients. In summary, rare variants in several collagen genes are particularly frequent in CM-1 cases and those in COL6A5 co-segregated with CM-1 in a Spanish multiplex family. COL6A5 has been previously associated with musculoskeletal phenotypes, but this is the first association with CM-1. Our findings underscore the contribution of rare genetic variants in collagen genes to CM-1, and suggest that CM-1 in the presence and absence of CTD symptoms is driven by different genes.

Association Between Resistance to Cerebrospinal Fluid Flow Near the Foramen Magnum and Cough-Associated Headache in Adult Chiari Malformation Type I

Cough-associated headaches (CAHs) are thought to be distinctive for Chiari malformation type I (CMI) patients and have been shown to be related to the motion of cerebrospinal fluid (CSF) near the foramen magnum (FM). We used computational fluid dynamics (CFD) to compute patient-specific resistance to CSF motion in the spinal canal for CMI patients to determine its accuracy in predicting CAH. Fifty-one symptomatic CMI patients with cerebellar tonsillar position (CTP) ≥ 5 mm were included in this study. The patients were divided into two groups based on their symptoms (CAH and non-CAH) by review of the neurosurgical records. CFD was utilized to simulate CSF motion, and the integrated longitudinal impedance (ILI) was calculated for all patients. A receiver operating characteristic (ROC) curve was evaluated for its accuracy in predicting CAH. The ILI for CMI patients with CAH (776 dyn/cm5, 288-1444 dyn/cm5; median, interquartile range) was significantly larger compared to non-CAH (285 dyn/cm5, 187-450 dyn/cm5; p = 0.001). The ILI was more accurate in predicting CAH in CMI patients than the CTP when the comparison was made using the area under the ROC curve (AUC) (0.77 and 0.70, for ILI and CTP, respectively). ILI ≥ 750 dyn/cm5 had a sensitivity of 50% and a specificity of 95% in predicting CAH. ILI is a parameter that is used to assess CSF blockage in the spinal canal and can predict patients with and without CAH with greater accuracy than CTP.

Rare and de novo coding variants in chromodomain genes in Chiari I malformation

Chiari I malformation (CM1), the displacement of the cerebellum through the foramen magnum into the spinal canal, is one of the most common pediatric neurological conditions. Individuals with CM1 can present with neurological symptoms, including severe headaches and sensory or motor deficits, often as a consequence of brainstem compression or syringomyelia (SM). We conducted whole-exome sequencing (WES) on 668 CM1 probands and 232 family members and performed gene-burden and de novo enrichment analyses. A significant enrichment of rare and de novo non-synonymous variants in chromodomain (CHD) genes was observed among individuals with CM1 (combined p = 2.4 × 10-10), including 3 de novo loss-of-function variants in CHD8 (LOF enrichment p = 1.9 × 10-10) and a significant burden of rare transmitted variants in CHD3 (p = 1.8 × 10-6). Overall, individuals with CM1 were found to have significantly increased head circumference (p = 2.6 × 10-9), with many harboring CHD rare variants having macrocephaly. Finally, haploinsufficiency for chd8 in zebrafish led to macrocephaly and posterior hindbrain displacement reminiscent of CM1. These results implicate chromodomain genes and excessive brain growth in CM1 pathogenesis.

Enrichment and Correlation Analysis of Serum miRNAs in Comorbidity Between Arnold-Chiari and Tourette Syndrome Contribute to Clarify Their Molecular Bases

Due to its rarity, coupled to a multifactorial and very heterogeneous nature, the molecular etiology of Arnold-Chiari (AC) syndrome remains almost totally unknown. Its relationship with other neuropsychiatric disorders such as Tourette syndrome (TS) is also undetermined. The rare comorbid status between both disorders (ACTS) complicates the framework of diagnosis and negatively affects the patients' quality of life. In this exploratory study, we aimed to identify serum microRNA expression profiles as molecular fingerprints for AC, TS, and ACTS, by using a high-throughput approach. For this aim, 10 AC patients, 11 ACTS patients, 6 TS patients, and 8 unaffected controls (NC) were recruited. Nine miRNAs resulted significantly differentially expressed (DE): let-7b-5p (upregulated in ACTS vs. TS); miR-21-5p (upregulated in ACTS vs. AC; downregulated in AC vs. TS); miR-23a-3p (upregulated in TS vs. NCs; downregulated in AC vs. TS); miR-25-3p (upregulated in AC vs. TS and NCs; downregulated in ACTS vs. AC); miR-93-5p (upregulated in AC vs. TS); miR-130a-3p (downregulated in ACTS and TS vs. NCs); miR-144-3p (downregulated in ACTS vs. AC; upregulated in AC vs. TS); miR-222-3p (upregulated in ACTS vs. NCs); miR-451a (upregulated in AC vs. TS and NCs; in ACTS vs. NCs). Altered expression of miRNAs was statistically correlated to neuroimaging and neuropsychological anomalies. Furthermore, computational analyses indicated that DE miRNAs are involved in AC and TS pathomechanisms. Finally, we propose the dysregulation of the miRNA set as a potential molecular tool for supporting the current diagnosis of AC, TS, and ACTS by using liquid biopsies, in an unbiased and non-invasive way.

Chiari 1 malformation and exome sequencing in 51 trios: the emerging role of rare missense variants in chromatin-remodeling genes

Type 1 Chiari malformation (C1M) is characterized by cerebellar tonsillar herniation of 3–5 mm or more, the frequency of which is presumably much higher than one in 1000 births, as previously believed. Its etiology remains undefined, although a genetic basis is strongly supported by C1M presence in numerous genetic syndromes associated with different genes. Whole-exome sequencing (WES) in 51 between isolated and syndromic pediatric cases and their relatives was performed after confirmation of the defect by brain magnetic resonance image (MRI). Moreover, in all the cases showing an inherited candidate variant, brain MRI was performed in both parents and not only in the carrier one to investigate whether the defect segregated with the variant. More than half of the variants were Missense and belonged to the same chromatin-remodeling genes whose protein truncation variants are associated with severe neurodevelopmental syndromes. In the remaining cases, variants have been detected in genes with a role in cranial bone sutures, microcephaly, neural tube defects, and RASopathy. This study shows that the frequency of C1M is widely underestimated, in fact many of the variants, in particular those in the chromatin-remodeling genes, were inherited from a parent with C1M, either asymptomatic or with mild symptoms. In addition, C1M is a Mendelian trait, in most cases inherited as dominant. Finally, we demonstrate that modifications of the genes that regulate chromatin architecture can cause localized anatomical alterations, with symptoms of varying degrees.

Arnold‐Chiari malformation type 1 as an unusual cause of acute respiratory failure: A case report

The authors urge clinicians to consider the possibility of Arnold‐Chiari Malformation type 1 with other central causes especially in cases where acute respiratory failure is unexplainable.

The Perplexity Surrounding Chiari Malformations - Are We Any Wiser Now?

Chiari malformations are a diverse group of abnormalities of the brain, craniovertebral junction, and the spine. Chiari 0, I, and 1.5 malformations, likely a spectrum of the same malformation with increasing severity, are due to the inadequacy of the para-axial mesoderm, which leads to insufficient development of occipital somites. Chiari II malformation is possibly due to nonclosure of the caudal end of the neuropore, with similar pathogenesis in the rostral end, which causes a Chiari III malformation. There have been significant developments in the understanding of this complex entity owing to insights into the pathogenesis and advancements in imaging modalities and neurosurgical techniques. This article aims to review the different types and pathophysiology of the Chiari malformations, along with a description of the various associated abnormalities. We also highlight the role of ante- and postnatal imaging, with a focus on the newer techniques in the presurgical evaluation, with a brief mention of the surgical procedures and the associated postsurgical complications.

Minimally invasive foramen magnum durectomy and obexostomy for treatment of craniocervical junction-related syringomyelia in adults: case series and midterm follow-up

OBJECTIVE

Craniocervical junction-related syringomyelia (CCJS) is the most common form of syringomyelia. Approximately 30% of patients treated with foramen magnum decompression (FMD) will show persistence, recurrence, or progression of the syrinx. The authors present a pilot study with a new minimally invasive surgery technique targeting the pathophysiology of CCJS in adult patients.

METHODS

The authors retrospectively analyzed the clinical and radiological features of a consecutive series of patients treated for CCJS. An FMD and FM durectomy were performed through a 1.5- to 2-cm skin incision. Then arachnoid adhesions were cleared, creating a permanent communication from the fourth ventricle to the new paraspinal extradural cavity (obexostomy) and with the spinal subarachnoid space. The hypothesis was that the new CSF pouch acts like a pressure leak, interrupting the CCJS pathogenesis.

RESULTS

Twenty-four patients (13 female, 21-61 years old) were treated between 2014 and 2018. The etiology of CCJS was Chiari malformation type I (CM-I) in 20 patients (83.3%), Chiari malformation type 0 (CM-0) in 2 patients (8.3%), and CCJ arachnoiditis in 2 patients (8.3%). Two patients underwent reoperations after failed FMD for CM-I at other institutions. No major surgical complication occurred. One patient had postoperative meningitis with no CSF fistula. On postoperative MRI, shrinkage of the syrinx was seen in all patients. No patients experienced recurrence of the CCJS. No patient required a subsequent operation. The mean duration of surgery was 72 ± 11 minutes (mean ± SD), and blood loss was 35-80 ml (mean 51 ml). Follow-up ranged from 12 to 58 months. The average overall improvement in modified Japanese Orthopaedic Association scores was 10% (p < 0.001). The Odom scale showed that 19 patients (79.1%) were satisfied, 4 (16.7%) remained the same, and 1 (4.2%) reported a poor outcome. All patients experienced postoperative improvement in perception of quality of life (p < 0.001).

CONCLUSIONS

Minimally invasive FM durectomy and obexostomy is a safe and effective treatment for CCJS and for patients who have not responded to other treatment.

Family History in Chiari Malformation Type I: Presentation and Outcome

BACKGROUND

Some patients with Chiari malformation type I (CM-1) present with a positive family history of CM-1, the significance of which remains unknown. We aimed to study whether family history affects the clinical presentation characteristics and surgical outcome of adult patients with CM-1.

METHODS

A database of adult patients with CM-1 presenting between January 1, 2006 and December 31, 2018 was used. Presenting characteristics were compared between patients with and without a family history (first, second, or third degree) of CM-1. Among surgically treated patients, perioperative and long-term outcomes, with favorable outcome defined as a Chiari Outcome Scale score ≥14, were compared between patients with and without CM-1 family history. All patients completed at least 6 months of postoperative follow-up.

RESULTS

The database consisted of 233 adult patients with CM-1, 14 of whom (6%) had a positive family history. Presenting characteristics were comparable between patients with and without a positive family history. A total of 150 patients underwent suboccipital decompression, 12 of whom (8%) had a positive family history. After a mean follow-up of 1.9 years, patients with a family history of CM-1 were significantly less likely to achieve a favorable outcome (odds ratio, 0.22; 95% confidence interval, 0.06-0.78; P = 0.019) while controlling for several covariates. Post hoc analysis showed that the difference was most significant when looking at pain symptoms.

CONCLUSIONS

Presentation characteristics are comparable between patients with and without a family history of CM-1. Patients with a positive family history may be less likely to respond favorably to suboccipital decompression.

Chiari I malformation and pregnancy: a comprehensive review of the literature to address common questions and to guide management

BACKGROUND

The optimal management of Chiari I malformation during pregnancy remains uncertain. Labor contractions, which increase intracranial pressure, and neuraxial anesthesia both carry the theoretical risk of brainstem herniation given the altered CSF dynamics inherent to the condition. Mode of delivery and planned anesthesia, therefore, require forethought to avoid potentially life-threatening complications. Since the assumed potential risks are significant, we seek to systematically review published literature regarding Chiari I malformation in pregnancy and, therefore, to establish a best practice recommendation based on available evidence.

METHODS

The English-language literature was systematically reviewed from 1991 to 2018 according to PRISMA guidelines to assess all pregnancies reported in patients with Chiari I malformation. After analysis, a total of 34 patients and 35 deliveries were included in this investigation. Additionally, a single case from our institutional experience is presented for illustrative purposes but not included in the statistical analysis.

RESULTS

No instances of brain herniation during pregnancy in patients with Chiari I malformation were reported. Cesarean deliveries (51%) and vaginal deliveries (49%) under neuraxial blockade and general anesthesia were both reported as safe and suitable modes of delivery. Across all publications, only one patient experienced a worsening of neurologic symptoms, which was only later discovered to be the result of a previously undiagnosed Chiari I malformation. Several patients underwent decompressive suboccipital craniectomy to treat the Chiari I malformation during the preconception period (31%), during pregnancy (3%), and after birth (6%). Specific data regarding maternal management were not reported for a large number (21) of these patients (60%). Aside from one abortion in our own institutional experience, there was no report of any therapeutic abortion or of adverse fetal outcome.

CONCLUSIONS

Although devastating maternal complications are frequently feared, very few adverse outcomes have ever been reported in pregnant patients with a Chiari I malformation. The available evidence is, however, rather limited. Based on our survey of available data, we recommend vaginal delivery under neuraxial blockade for truly asymptomatic patients. Furthermore, based on our own experience and physiological conceptual considerations, we recommend limiting maternal Valsalva efforts either via Cesarean delivery under regional or general anesthesia or by choosing assisted vaginal delivery under neuraxial blockade. There is no compelling reason to offer suboccipital decompression for Chiari I malformation during pregnancy. For patients with significant neurologic symptoms prior to conception, decompression prior to pregnancy should be considered.

Clivus length distinguishes between asymptomatic healthy controls and symptomatic adult women with Chiari malformation type I

PURPOSE

While the presence of cerebellar tonsillar descent in radiological images has been used as evidence of Chiari malformation type I (CMI), tonsillar ectopia alone is insufficient to identify individuals with symptomatic CMI. This study sought to identify differences in brain morphology between symptomatic CMI and healthy controls in adult females.

METHODS

Two hundred and ten adult females with symptomatic CMI and 90 age- and body mass index-matched asymptomatic female controls were compared using seven brain morphometric measures visible on magnetic resonance images. The CMI and control groups were divided into four subgroups based on the tonsillar position (TP) relative to the foramen magnum: group 1 was made up of healthy controls with normal TP (TP < 0 mm); group 2 was comprised of control individuals with low-lying TP (1-5 mm); group 3 was comprised of symptomatic CMI patients with low-lying TP (1-5 mm); group 4 contained symptomatic CMI patients with severe tonsillar descent (6-13 mm).

RESULTS

All morphometrics for symptomatic CMI with severe tonsillar descent were significantly different than those for both control groups. The CMI group with low-lying TP was significantly different for four measures when compared to controls with normal TP. However, only clivus length was statistically different between the CMI and healthy control groups with low-lying TP.

CONCLUSION

This study demonstrates that clivus length distinguishes adult female healthy individuals with low-lying tonsils from those with symptomatic CMI. Further investigation is required to understand the importance of a shorter clivus length on CMI symptomatology and pathophysiology.

Prevalence and Impact of Underlying Diagnosis and Comorbidities on Chiari 1 Malformation

BACKGROUND

Chiari malformation type 1 affects approximately one in 1,000 people symptomatically, although one in 100 meet radiological criteria, making it a common neurological disorder. The diagnosis of underlying conditions has become more sophisticated, and new radiological markers of disease have been described. We sought to determine the prevalence and impact of additional comorbidities and underlying diagnoses in patients with Chiari malformation type 1 on symptomatology and surgical treatment.

METHODS

A retrospective review of 612 pediatric patients with a Chiari malformation type 1 diagnosis and imaging data evaluated between 2008 and 2018 was performed. Because of extensive clinical heterogeneity, patients were separated into four categories based on their primary comorbidities (nonsyndromic, central nervous system, skeletal, and multiple congenital anomalies) to identify associations with age of onset, radiographic measurements, syringomyelia, and surgical treatment.

RESULTS

The largest group had nonsyndromic Chiari malformation type 1 (70%) and the latest age at diagnosis of any group. In the syndromic group, 6% were diagnosed with a known genetic abnormality, with overgrowth syndromes being the most common. Patients with multiple congenital anomalies had the earliest Chiari malformation type 1 onset, the most severe tonsillar ectopia and obex position, and were overrepresented among surgical cases. Although there were no statistically significant differences between groups and rates of syrinx, we observed differences in individual diagnoses.

CONCLUSION

The underlying diagnoses and presence of comorbidities in patients with Chiari malformation type 1 impacts rates of syringomyelia and surgery. Although most Chiari malformation type 1 cases are nonsyndromic, clinical evaluation of growth parameters, scoliosis, and joint hypermobility should be routine for all patients as they are useful to determine syringomyelia risk and may impact treatment.

Epidemiology of Symptomatic Chiari Malformation in Tatarstan: Regional and Ethnic Differences in Prevalence

BACKGROUND

Epidemiology can assess the effect of Chiari I malformation (CM1) on the neurological health of a population and evaluate factors influencing CM1 development.

OBJECTIVE

To analyze the regional and ethnic differences in the prevalence of CM1.

METHODS

The population of the Republic of Tatarstan (RT) in the Russian Federation was evaluated for patients with CM1 symptoms over an 11-yr period. Typical symptoms of CM1 were found in 868 patients. Data from neurological examination and magnetic resonance imaging (MRI) measurement of posterior cranial fossa structures were analyzed.

RESULTS

MRI evidence of CM1, defined as cerebellar tonsils lying at least 5 mm inferior to the foramen magnum, was found in 67% of symptomatic patients. Another 33% of symptomatic patients had 2 to 4 mm of tonsillar ectopia, which we defined as "borderline Chiari malformation type 1 (bCM1)." The period prevalence in the entire RT for symptomatic CM1 was 20:100 000; for bCM1 was 10:100 000; and for CM1 and bCM1 together was 30:100 000. Prevalence of patients with CM1 symptoms was greater in the northern than southern districts of Tatarstan, due to a high prevalence (413:100 000) of CM1 in the Baltasy region in one of the northern districts.

CONCLUSION

One-third of patients with typical symptoms of CM1 had less than 5 mm of tonsillar ectopia (bCM1). Assessments of the health impact of CM1-type symptoms on a patient population should include the bCM1 patient group. A regional disease cluster of patients with Chiari malformation was found in Baltasy district of RT and needs further study.

PedsQL for prediction of postoperative patient-reported outcomes following Chiari decompression surgery

OBJECTIVE

The purpose of this study is to determine if the preoperative Pediatric Quality of Life Inventory (PedsQL) score is predictive of short- and intermediate-term PedsQL outcomes following Chiari decompression surgery. The utility of preoperative patient-reported outcomes (PROs) in predicting pain, opioid consumption, and long-term PROs has been demonstrated in adult spine surgery. To the best of the authors' knowledge, however, there is currently no widely accepted tool to predict short-, intermediate-, or long-term outcomes after pediatric Chiari decompression surgery.

METHODS

A prospectively maintained database was retrospectively reviewed. Patients who had undergone first-time decompression for symptomatic Chiari malformation were identified and grouped according to their preoperative PedsQL scores: mild disability (score 80-100), moderate disability (score 60-79), and severe disability (score < 60). PedsQL scores at the 6-week, 3-month, and/or 6-month follow-ups were collected. Preoperative PedsQL subgroups were tested for an association with demographic and perioperative characteristics using one-way ANOVA or chi-square analysis. Preoperative PedsQL subgroups were tested for an association with improvements in short- and intermediate-term PedsQL scores using one-way ANOVA and a paired Wilcoxon signed-rank test controlling for statistically different demographic characteristics when appropriate.

RESULTS

A total of 87 patients were included in this analysis. According to their preoperative PedsQL scores, 28% of patients had mild disability, 40% had moderate disability, and 32% had severe disability. There was a significant difference in the prevalence of comorbidities (p = 0.009) and the presenting symptoms of headaches (p = 0.032) and myelopathy (p = 0.047) among the subgroups; however, in terms of other demographic or operative factors, there was no significant difference. Patients with greater preoperative disability demonstrated statistically significantly lower PedsQL scores at all postoperative time points, except in terms of the parent-reported PedsQL at 6 months after surgery (p = 0.195). Patients with severe disability demonstrated statistically significantly greater improvements (compared to preoperative scores) in PedsQL scores at all time points after surgery, except in terms of the 6-week and 6-month PROs and the 6-month parent-reported outcomes (p = 0.068, 0.483, and 0.076, respectively).

CONCLUSIONS

Patients with severe disability, as assessed by the PedsQL, had lower absolute PedsQL scores at all time points after surgery but greater improvement in short- and intermediate-term PROs. The authors conclude that the PedsQL is an efficient and accurate tool that can quickly assess patient disability in the preoperative period and predict both short- and intermediate-term surgical outcomes.

Development of Common Data Elements for Use in Chiari Malformation Type I Clinical Research: An NIH/NINDS Project

The management of Chiari I malformation (CMI) is controversial because treatment methods vary and treatment decisions rest on incomplete understanding of its complex symptom patterns, etiologies, and natural history. Validity of studies that attempt to compare treatment of CMI has been limited because of variable terminology and methods used to describe study subjects. The goal of this project was to standardize terminology and methods by developing a comprehensive set of Common Data Elements (CDEs), data definitions, case report forms (CRFs), and outcome measure recommendations for use in CMI clinical research, as part of the CDE project at the National Institute of Neurological Disorders and Stroke (NINDS) of the US National Institutes of Health. A working group, comprising over 30 experts, developed and identified CDEs, template CRFs, data dictionaries, and guidelines to aid investigators starting and conducting CMI clinical research studies. The recommendations were compiled, internally reviewed, and posted online for external public comment. In October 2016, version 1.0 of the CMI CDE recommendations became available on the NINDS CDE website. The recommendations span these domains: Core Demographics/Epidemiology; Presentation/Symptoms; Co-Morbidities/Genetics; Imaging; Treatment; and Outcome. Widespread use of CDEs could facilitate CMI clinical research trial design, data sharing, retrospective analyses, and consistent data sharing between CMI investigators around the world. Updating of CDEs will be necessary to keep them relevant and applicable to evolving research goals for understanding CMI and its treatment.

Three-Dimensional CT Morphometric Image Analysis of the Clivus and Sphenoid Sinus in Chiari Malformation Type I

This study evaluated three-dimensional (3D) volumetric image reconstructions to identify morphological differences of the clivus and sphenoid sinus on computed tomography (CT) scans of Chiari malformation type I (CMI) and control subjects. Axial CT images of adult females for 30 CMI subjects and 30 age and body mass index (BMI) matched controls were used for this retrospective study. 3D volumetric reconstructions were created from the bone windows of axial data following image registration for position and orientation correction of the head. The volume, surface area, linear dimensions and spatial position in the x, y, and z-axes were computed separately for the clivus and the sphenoid sinus for each subject. Eleven parameters were found to be significantly different between CMI subjects compared to controls. Most notably, clivus volume was reduced by 31% on average in CMI subjects. In contrast, we found that the sphenoid sinus volume was 38% greater on average in CMI subjects. Moreover, clivus length, height, width, and thickness were 3.7, 2.8, 3.0 and 9.4 mm reduced, respectively, in CMI subjects. This is the first study to demonstrate cephalometric differences in the 3D morphology of the clivus and sphenoid sinus between CMI subjects and controls.

An examination of pain, disability, and the psychological correlates of Chiari Malformation pre- and post-surgical correction

BACKGROUND

50% of patients with Chiari Malformation (CM) report a history of depression; however, rates of other psychological symptoms are unknown. Further, it is unclear whether surgical correction impacts pain, disability, and psychological symptoms.

OBJECTIVE

/Hypothesis: We examined rates of symptoms in a nationwide sample of CM patients who had (n = 639) and had not (n = 551) undergone surgical correction. We hypothesized lower symptom severity in the latter group.

METHODS

Participants completed assessments and submitted pre-surgical MRI scans online (n = 286). Informed by the Fear-Avoidance Model of pain, we controlled for psychological symptoms when assessing pain/disability, and pain/disability when assessing psychological symptoms.

RESULTS

Overall, high rates of depression (44% moderate-severe) and anxiety (60% moderate-severe) were reported. Groups (surgery vs. no-surgery) did not differ in the proportion of patients meeting cutoff scores for current disability; however, the no-surgery group was more likely to meet cutoffs for anxiety (χ2 = 11.26, p < .05), stress (χ2 = 14.63, p < .01) and health anxiety (χ2 = 4.63, p < .05). The surgery group reported lower levels of continuous affective pain F(1, 1065) = 10.28, p < .001), anxiety F(1,1026) = 4.96, p < .05) and stress F(1, 978) = 5.67, p < .05) although effect sizes were small (η2s ranging from 0.010 to 0.006, Cohen's D ranging from 0.17 to 0.25).

CONCLUSION

CM patients experience high rates of psychological symptomatology regardless of surgical status, suggesting that all CM patients may benefit from evidence-based interventions to address anxiety and depression.

Management of Chiari malformations: opinions from different centers-a review

PURPOSE

Surgical decision-making in Chiari malformation type I (CM-I) patients tends to depend on the presence of neurological signs and symptoms, syringomyelia, and/or scoliosis, but significant variability exists from center to center. Here, we review the symptoms of CM-I in children and provide an overview of the differences in opinion regarding surgical indications, preferred surgical techniques, and measures of outcome.

METHODS

A review of the literature was performed to identify publications relevant to the surgical management of pediatric CM-I patients.

RESULTS

Most surgeons agree that asymptomatic patients without syringomyelia should not undergo prophylactic surgery, while symptoms of brainstem compression and/or lower cranial nerve dysfunction warrant surgery. Patients between these extremes, however, remain controversial, as does selection of the most appropriate surgical technique.

CONCLUSIONS

The optimal surgical procedure for children with CM-I remains a point of contention, and widespread variability exists between and within centers.

Chiari malformation type I: what information from the genetics?

PURPOSE

Chiari malformation type I (CMI), a rare disorder of the craniocerebral junction with an estimated incidence of 1 in 1280, is characterized by the downward herniation of the cerebellar tonsils of at least 5 mm through the foramen magnum, resulting in significant neurologic morbidity. Classical CMI is thought to be caused by an underdeveloped occipital bone, resulting in a posterior cranial fossa which is too small to accommodate the normal-sized cerebellum. In this review, we dissect the lines of evidence supporting a genetic contribution for this disorder.

METHODS

We present the results of two types of approaches: animal models and human studies encompassing different study designs such as whole genome linkage analysis, case-control association studies, and expression studies. The update of the literature also includes the most recent findings emerged by whole exome sequencing strategy.

RESULTS

Despite evidence for a genetic component, no major genes have been identified and the genetics of CMI is still very much unknown. One major challenge is the variability of clinical presentation within CMI patient population that reflects an underlying genetic heterogeneity.

CONCLUSIONS

The identification of the genes that contribute to the etiology of CMI will provide an important step to the understanding of the underlying pathology. The finding of a predisposing gene may lead to the development of simple and accurate diagnostic tests for better prognosis, counseling, and clinical management of patients and their relatives.

«A case of a pharmacoresistant tachyarrhythmia associated with Arnold-Chiari malformation»

Introduction: Arnold-Chiari malformation is a group of congenital malformations of the hindbrain. Common symptoms include cephalgia, vestibular, cerebral and cochlear disorders We present a case of pharmacoresistant tachyarrhythmia associated with Arnold-Chiari malformation.Case Description: A 49-year-old female patient had an Arnold-Chiari malformation (ACM), syringomyelia, a retrocerebellar cyst and a 6 year history of tachyarrhythmia. Heart rhythm normalized after Chiari decompression.Conclusion: ACM can lead to heart rhythm disorders.