Chiari malformation and syringomyelia

Case report: CSF hypotension secondary to a free syringo-subarachnoid-peritoneal shunt

INTRODUCTION

Syringomyelia is present in 40% of pediatric patients with Chiari malformation. Typically treated with posterior fossa decompression, some cases require further intervention such as syrinx shunting.

CASE REPORT

We report a 16-year-old female with Chiari type 1 malformation and syringomyelia who underwent posterior fossa decompression and subsequent free syringo-subarachnoid-peritoneal shunting. The patient developed symptoms of CSF overdrainage, and imaging indicated CSF hypotension. A distal catheter ligation temporarily improved symptoms, but eventually, a programmable ventricular shunt was necessary due to shunt dependence.

CONCLUSION

This case highlights the rare complication of CSF overdrainage from syrinx shunting and the importance of shunt selection considerations.

Acute Respiratory Failure Requiring Invasive Ventilation in Adults With Congenital Syringomyelia/Arnold-Chiari Malformations: A Systematic Review

Arnold-Chiari malformations (ACM) and congenital syringomyelia/syrinx are rare neurological phenomenons that can present as acute respiratory failure and contribute to multiple extubation failures despite surgical intervention. A systematic review was conducted to scrutinize the current literature, screening 65 papers and including 12 papers (13 patients). Sixty-one percent of patients had type 1 ACM and 70% had a congenital syringomyelia. Neurosurgical intervention occurred in seven patients, five patients had at least one extubation failure which was due to apnea or reoccurrence of respiratory failure, and eight patients needed tracheostomies. The neurosurgical intervention aims to improve patient symptoms, but our data and current literature suggest that patients with these pathologies still undergo long ventilation weans and are not liberated from the ventilator due to ongoing respiratory failure.

The Surgical Strategy Cerebrospinal Fluid Decompression Facilitates Outcomes of Adults with Chiari Malformation Type I: An Observational, Real-World, Single-Center Study of 528 Patients

OBJECTIVE

We designed this study to introduce the surgical strategy cerebrospinal fluid (CSF) decompression in treatment of Chiari malformation type I and compared CSF decompression with other surgical strategies to provide a solid basis for patient counseling.

METHODS

The study enrolled 528 consecutive patients with CMI who underwent surgical interventions from 2012 to 2022. The surgical strategy for these patients was bony and dural decompression, anatomical reduction of herniated tonsils, or CSF decompression. Short-term results were determined after 3 months; long-term outcomes were evaluated at last follow-up (at least 18 months).

RESULTS

CSF decompression was independently associated with better long- or short-term primary outcomes than anatomical reduction of herniated tonsils or bony and dural decompression (P < 0.001). Compared with short-term, the long-term outcomes were better in patients who underwent CSF decompression (P = 0.035), but were worse in patients with bony and dural decompression (P = 0.03). Specific surgical techniques cannot affect the long- and short-term outcomes of patients with Chiari malformation type I. CSF decompression provided better long-term syringomyelia improvement than short-term (181/218, 83% vs. 169/218, 77.5%; P < 0.001).

CONCLUSIONS

CSF decompression, but not a specific surgical technique or operative method, was associated with favorable neurological outcomes in ADULT patients with Chiari malformation type I. The surgical technique and operative method should be selected according to the characteristics of each patient and the intraoperative condition to normalize CSF circulation at the craniovertebral junction area. The intraoperative target, smooth CSF flow out from the fourth ventricle and in to the bilateral Luschka foramina, could be observed.

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.

An autologous duraplasty in situ technique in the treatment of Chiari malformation Type I: a prospective study

OBJECTIVE

Our study aims to prospectively compare an autologous duraplasty in situ technique (IS group) with the synthetic dural graft duraplasty (SDG group) to clarify the effectiveness and superiority of the former in the treatment of patients with Chiari malformation type 1 (CM-I).

METHOD

29 patients with CM-I were randomly assigned to either IS or SDG group. In both groups, a dissection from the occipital bone was performed. All procedures were performed by the same surgeon. The two duraplasty methods were compared in terms of surgical factors and complications. Data analysis was done for the baseline material, the neurological outcome and MRI-documented syrinx size at the 6 month follow-up.

RESULT

29 patients were enrolled in this study, 14 in the IS group and 15 in the SDG group. The results showed no significant difference in operation time (P = 0.916), amount of bleeding (P = 0.120), operation complications, hospitalization time (P = 0.854) and prognosis between the two groups. The hospitalization cost of IS group was 15,125 yuan less than that of SDG group (P < 0.05).

CONCLUSION

The autogenous duraplasty in situ technique is a novel, simple, effective and economical surgical management for patients with CM-I.

Comprehensive comparative study of Chiari-like malformation in veterinary and human medicine

This review aims to enrich our understanding of Chiari-like malformation (CLM) by combining human and veterinary insights, and providing a detailed cross-species overview. CLM is a developmental abnormality characterised by caudal displacement of the hindbrain into the foramen magnum due to an entire brain parenchymal shift caused by insufficient skull volume. This malformation leads to a progressive obstruction at the craniocervical junction, which disrupts the normal cerebrospinal fluid flow, leading to secondary syringomyelia. The clinical signs of CLM and syringomyelia include phantom scratching, head tilt, head tremor, ataxia, tetraparesis, pain, muscle atrophy, and scoliosis or torticollis. Magnetic resonance imaging remains the gold standard for diagnosing CLM, since it allows the visualisation of abnormal findings such as the caudal cerebellar herniation, caudal cerebellar compression from occipital dysplasia, and attenuated cerebrospinal fluid cisternae. Although various medical and surgical interventions, including foramen magnum decompression, can provide temporary symptomatic/clinical sign relief, current literature shows a lack of sustained long-term efficacy. Therefore, additional research is needed to evaluate the long-term effects of existing treatment strategies and to compare different techniques utilised in conjunction with foramen magnum decompression.

Anatomy and mobility in the adult cadaveric craniocervical junction

Genetic diseases with craniofacial malformations can be associated with anomalies of the craniocervical joint (CCJ). The functions of the CCJ are thus impaired, as mobility may be either limited by abnormal bone fusion causing headaches, or exaggerated in the case of hypermobility, which may cause irreparable damage to the spinal cord. Restoring the balance between mobility and stability requires surgical correction in children. The anatomy and biomechanics of the CCJ are quite unique, yet have been overlooked in the past decades. Pediatric evidence is so scarce, that investigating the adult CCJ is our best shot to disentangle the form-function relationships of this anatomical region. The motivation of the present study was to understand the morphological and functional basis of motion in the CCJ, in the hope to find morphological features accessible from medical imaging able to predict mobility. To do so, we have quantified the in-vitro kinematics of the CCJ in nine cadaveric asymptomatic adults, and estimated a wide range of mobility variables covering the complexity of spinal motion. We compared these variables with the shape of the occipital, the atlas and the axis, obtained using a dense geometric morphometric approach. Morphological joint congruence was also quantified. Our results suggest a strong relationship between bone shape and motion, with the overall geometry predicting best the primary movements, and the joint facets predicting best the secondary movements. We propose a functional hypothesis stating that the musculoligamental system determines movements of great amplitude, while the shape and congruence of joint facets determine the secondary and coupled movements, especially by varying the geometry of bone stops and the way ligaments are tensioned. We believe this work will provide valuable insights in understanding the biomechanics of the CCJ. Furthermore, it should help surgeons treating CCJ anomalies by enabling them to translate objectives of functional and clinical outcome into clear objectives of morphological outcome.

Chiari Type I Revision Decompressive Surgery Indications and Operative Technique: Experience in a Large Adult Cohort

BACKGROUND

Chiari malformation is characterized by inferior displacement of the cerebellar tonsils through the foramen magnum, frequently resulting in strain related headaches, and motor/sensory dysfunction. Chiari decompression technique varies significantly, possibly contributing to frequent revisions. We reviewed revision Chiari decompressions at our institution to determine the primary indications for revision and outcomes after revision.

METHODS

We retrospectively reviewed patients who underwent revision of Chiari decompression at our institution from 2005 to 2020. Demographics, indications for revision surgery, operative techniques, imaging findings, and preoperative/postoperative symptoms were collected. χ2 test was performed to determine statistical significance using a P < 0.05. Independent predictors of operative outcomes were identified.

RESULTS

A total of 46 patients (91% females, mean age 38.8 years) were included for analysis. The median time to revision surgery was 69.1 months (range 0-364 months) with headache (n = 37, 80%) being the most commonly recurring symptom. Large craniectomy (n = 28, 61%) was the most frequent indication for revision surgery. Thirty-two (70%) patients underwent cranioplasty, 20 (43%) required duraplasty, 15 (33%) required arachnoid dissection, and 15 (33%) required tonsillar reduction during revision surgery. Postrevision follow-up (at 8.9 ± 5.2 months average, range 1-18 months), revealed an average reduction in all Chiari-related symptoms relative to symptoms before the revision.

CONCLUSIONS

The most common indication for revision Chiari decompression was a large craniectomy resulting in cerebellar ptosis. We found that tonsillar reduction paired with modest craniectomy achieved near-complete resolution of symptoms with minimal complications. For patients with recurrent or persistent sequelae of Chiari malformation after decompression, revision may reduce symptom severity.

From Text to Insight: A Natural Language Processing-Based Analysis of Topics and Trends in Neurosurgery

BACKGROUND AND OBJECTIVES

Neurosurgical research is a rapidly evolving field, with new research topics emerging continually. To provide a clearer understanding of the evolving research landscape, our study aimed to identify and analyze the prevalent research topics and trends in Neurosurgery.

METHODS

We used BERTopic, an advanced natural language processing-based topic modeling approach, to analyze papers published in the journal Neurosurgery . Using this method, topics were identified based on unique sets of keywords that encapsulated the core themes of each article. Linear regression models were then trained on the topic probabilities to identify trends over time, allowing us to identify "hot" (growing in prominence) and "cold" (decreasing in prominence) topics. We also performed a focused analysis of the trends in the current decade.

RESULTS

Our analysis led to the categorization of 12 438 documents into 49 distinct topics. The topics covered a wide range of themes, with the most commonly identified topics being "Spinal Neurosurgery" and "Treatment of Cerebral Ischemia." The hottest topics of the current decade were "Peripheral Nerve Surgery," "Unruptured Aneurysms," and "Endovascular Treatments" while the cold topics were "Chiari Malformations," "Thromboembolism Prophylaxis," and "Infections."

CONCLUSION

Our study underscores the dynamic nature of neurosurgical research and the evolving focus of the field. The insights derived from the analysis can guide future research directions, inform policy decisions, and identify emerging areas of interest. The use of natural language processing in synthesizing and analyzing large volumes of academic literature demonstrates the potential of advanced analytical techniques in understanding the research landscape, paving the way for similar analyses across other medical disciplines.

Functional Anatomy of the Spinal Cord

Localization of lesions in the spinal cord requires knowledge of the functional anatomy of gray and white matter tracts. Using decussation points for white matter tracts can help determine lesion level. Pathologies can affect gray and white matter tracts in distinct ways and pattern recognition can help narrow down the differential diagnosis.

Magnetic resonance imaging-based classification of the myodural bridge complex and its influencing factors

Cerebrospinal fluid (CSF) circulation is considered the third circulation of the human body. Recently, some scholars have proposed the myodural bridge (MDB) as a novel power source for CSF flow. Moreover, the suboccipital muscles can exert a driving force on the CSF via the MDB. This hypothesis is directly supported by head rotation and nodding movements, which can affect CSF circulation. The MDB has been validated as a normal structure in humans and mammals. In addition, the fusion of MDB fibers of different origins that act in concert with each other forms the MDB complex (MDBC). The MDBC may be associated with several CSF disorder-related neurological disorders in clinical practice. Therefore, the morphology of the MDBC and its influencing factors must be determined. In this study, T2-weighted imaging sagittal images of the cervical region were analyzed retrospectively in 1085 patients, and magnetic resonance imaging (MRI) typing of the MDBC was performed according to the imaging features of the MDBC in the posterior atlanto-occipital interspace (PAOiS) and posterior atlanto-axial interspace (PAAiS). The effects of age and age-related degenerative changes in the cervical spine on MRI staging of the MDBC were also determined. The results revealed four MRI types of the MDBC: type A (no MDBC hyposignal shadow connected to the dura mater in either the PAOiS or PAAiS), type B (MDBC hyposignal shadow connected to the dura mater in the PAOiS only), type C (MDBC hyposignal shadow connected to the dura mater in the PAAiS only), and type D (MDBC hyposignal shadow connected to the dura mater in both the PAOiS and PAAiS). The influencing factors for the MDBC typing were age (group), degree of intervertebral space stenosis, dorsal osteophytosis, and degenerative changes in the cervical spine (P < 0.05). With increasing age (10-year interval), the incidence of type B MDBC markedly decreased, whereas that of type A MDBC increased considerably. With the deepening of the degree of intervertebral space stenosis, the incidence of type C MDBC increased significantly, whereas that of type A MDBC decreased. In the presence of dorsal osteophytosis, the incidence of type C and D MDBCs significantly decreased, whereas that of type A increased. In the presence of protrusion of the intervertebral disc, the incidence of type B, C, and D MDBCs increased markedly, whereas that of type A MDBC decreased considerably, with cervical degenerative changes combined with spinal canal stenosis. Moreover, the incidence of both type C and D MDBCs increased, whereas that of type A MDBC decreased. Based on the MRI signal characteristics of the dural side of the MDBC, four types of the MDBC were identified. MDBC typing varies dynamically according to population distribution, depending on age and cervical degeneration (degree of intervertebral space stenosis, vertebral dorsal osteophytosis formation, simple protrusion of intervertebral disc, and cervical degeneration changes combined with spinal canal stenosis, except for the degree of protrusion of the intervertebral disc and the degree of spinal canal stenosis); however, it is not influenced by sex.

Decoding Chiari Malformation and Syringomyelia: From Epidemiology and Genetics to Advanced Diagnosis and Management Strategies

Chiari Malformation and Syringomyelia are neurosurgical entities that have been the subject of extensive research and clinical interest. Globally prevalent, these disorders vary demographically and have witnessed evolving temporal trends. Chiari Malformation impacts the normal cerebrospinal fluid flow, consequently affecting overall health. Key observations from canine studies offer pivotal insights into the pathogenesis of Syringomyelia and its extrapolation to human manifestations. Genetics plays a pivotal role; contemporary knowledge identifies specific genes, illuminating avenues for future exploration. Clinically, these disorders present distinct phenotypes. Diagnostically, while traditional methods have stood the test of time, innovative neurophysiological techniques are revolutionizing early detection and management. Neuroradiology, a cornerstone in diagnosis, follows defined criteria. Advanced imaging techniques are amplifying diagnostic precision. In therapeutic realms, surgery remains primary. For Chiari 1 Malformation, surgical outcomes vary based on the presence of Syringomyelia. Isolated Syringomyelia demands a unique surgical approach, the effectiveness of which is continually being optimized. Post-operative long-term prognosis and quality of life measures are crucial in assessing intervention success. In conclusion, this review amalgamates existing knowledge, paving the way for future research and enhanced clinical strategies in the management of Chiari Malformation and Syringomyelia.

Interleukin-31 in serum and cerebrospinal fluid of dogs with syringomyelia

BACKGROUND

Syringomyelia is a spinal cord cavity containing cerebrospinal fluid (CSF)-like fluid. If syringomyelia asymmetrically involves the dorsal horn grey matter of the spinal cord, affected dogs show increased signs of dysesthesia and neuropathic pain, like increased itching behaviour. In the dorsal horn, amongst others, receptors for Interleukin-31 (IL-31) can be found. IL-31 is one of the main cytokines involved in the pathogenesis of pruritus in atopic dermatitis in different species. This study investigates suspected elevated levels of IL-31 in serum and CSF of dogs showing signs of pain or increased itching behaviour related to syringomyelia. The IL-31 were measured in archived samples (52 serum and 35 CSF samples) of dogs with syringomyelia (n = 48), atopic dermatitis (n = 3) and of healthy control dogs (n = 11) using a competitive canine IL-31 ELISA.

RESULTS

Mean serum IL-31 level in dogs with syringomyelia was 150.1 pg/ml (n = 39), in dogs with atopic dermatitis 228.3 pg/ml (n = 3) and in healthy dogs 80.7 pg/ml (n = 10). Mean CSF IL-31 value was 146.3 pg/ml (n = 27) in dogs with syringomyelia and 186.2 pg/ml (n = 8) in healthy dogs. Individual patients with syringomyelia (especially dogs with otitis media or otitis media and interna or intervertebral disc herniation) showed high IL-31 levels in serum and CSF samples, but the difference was not statistically significant. IL-31 serum and CSF levels did not differ significantly in dogs with syringomyelia with or without itching behaviour and with or without signs of pain.

CONCLUSION

Based on this study, increased IL-31 levels seem not to be correlated with itching behaviour or signs of pain in dogs with syringomyelia, but might be caused by other underlying diseases.

The Originality of Neuro Rehabilitation Protocols in a Definitive Case of Syringomyelia Related to Chiari I Malformation

Syringomyelia is a center-medullary syndrome characterized by the presence of fluid-filled spaces known as syrinx within the spinal canal. Arnold Chiari Malformation (CM-I), a rhombencephalon anomaly formerly identified as hindbrain hernia, is usually associated with it. This disorder causes the brain (cerebellum) to bulge through the opening in the skull known as the foramen magnum. Some asymptomatic patients may develop symptoms quickly if they jolt their heads and cough for a lengthy period of time. Syringomyelia can be caused by trauma, illness, inflammation, or previous surgery that affects the circulation of cerebral spinal fluid resulting in CSF flow obstruction. The discomfort is acute and progressive, radiating to the neck and shoulder, and is accompanied by sensory loss, motor atrophy, decreased hearing, oscillopsia, and cerebellar abnormalities. This case report is of a 39-year-old woman diagnosed with syringomyelia associated with Arnold Chiari malformation and showed similar symptoms managed by foramen decompression and tonsillar elevation surgery. It involves removing a small piece of bone from the skull and a small section of the 1st vertebra from the back of the neck and head. In this way, there is an increase in skull space. Decompression of the spinal canal increases the size of the subarachnoid cisterns and constricts the syrinx cavity. After surgery, physiotherapy was advised because all superficial sensations over C8 and T1 were diminished, the range of motion along with strength was reduced, doing daily activities was difficult, and quality of life was affected. So, by decreasing symptoms and improving the patient's quality of life, physiotherapy improved the patient's condition significantly in this case report. The rationale of this study is to show the importance of physiotherapy in recovering after a neurological condition followed by corrective neurosurgery.

Single-cell transcriptomics reveals ependymal subtypes related to cytoskeleton dynamics as the core driver of syringomyelia pathological development

Syringomyelia is a common clinical lesion associated with cerebrospinal fluid flow abnormalities. By a reversible model with chronic extradural compression to mimic human canalicular syringomyelia, we explored the spatiotemporal pathological alterations during syrinx development. The most dynamic alterations were observed in ependymal cells (EPCs), oligodendrocyte lineage, and microglia, as a response to neuroinflammation. Among different cell types, EPC subtypes experienced obvious dynamic alterations, which were accompanied by ultrastructural changes involving the ependymal cytoskeleton, cilia, and dynamic injury in parenchyma primarily around the central canal, corresponding to the single-cell transcripts. After effective decompression, the syrinx resolved with the recovery of pathological damage and overall neurological function, implying that for syringomyelia in the early stage, there was still endogenous repair potential coexisting with immune microenvironment imbalance. Ependymal remodeling and cilia restoration might be important for better resolution of syringomyelia and parenchymal injury recovery.

Pain-depression relationship, quality of life and acceptance of illness among patients with Chiari malformation type I: A cross-sectional study

Chiari malformation type I (CM-I) is a congenital anomaly of the hindbrain. The most common symptoms include suboccipital tussive headache, dizziness and neck pain. Recently there has been growing interest in the psychological and psychiatric aspects of functioning in patients with CM-I, which have a significant effect on treatment outcomes and quality of life (QoL). The aim of the study was to assess the severity of depressive symptoms and the QoL in patients with CM-I and to identify the main factors responsible for these phenomena. A total of 178 people participated in the study and were divided into 3 groups: patients with CM-I who had undergone surgery (n = 59); patients with CM-I who had not undergone surgery (n = 63); and healthy volunteers (n = 56). Psychological evaluation included a set of questionnaires: the Beck Depression Inventory II, the World Health Organization shortened version of the WHOQOL-100 quality of life questionnaire, the Acceptance of Illness Scale and the Beliefs about Pain Control Questionnaire. Results showed that the control group participants obtained significantly better results than both groups of CM-I patients in terms of all indicators of QoL, symptoms of depression, acceptance of illness, pain level (average and present) and perceived influence of doctors regarding coping with pain. Patients with CM-I (operated and non-operated) obtained similar results in most of the questionnaires and the QoL indices correlated significantly with the majority of the analyzed variables. Moreover, CM-I patients with higher depression scores described their pain as more severe and had a stronger belief that pain levels were not influenced by them but only by doctors, or that it could be controlled randomly; they were also less willing to accept their illness. CM-I symptoms affect the mood and QoL of patients. Psychological and psychiatric care should be the golden standard in managing this clinical group.

A Systematic Review of Non-Opioid Pain Management in Chiari Malformation (Type 1) Patients: Current Evidence and Novel Therapeutic Opportunities

Chiari Malformation Type I (CM) includes a range of cranial abnormalities at the junction of the skull with the spine, with common symptoms including pain and headaches. Currently, CM pain is managed medically through anti-inflammatory drugs, muscle relaxants, and opioids, while surgical management includes posterior fossa decompression. Given the adverse effects of opioid use, and an ongoing opioid epidemic, there is a need for safe, non-opioid alternatives for clinical pain management. This systematic review was performed to provide an update on the current literature pertaining to the treatment of CM pain with non-opioid alternatives. A literature search was performed in June 2022 utilizing the PubMed and Google Scholar databases, and articles were identified that included information regarding non-opioid pain management in CM patients. A total of 90 articles were obtained from this search, including 10 relevant, drug-specific studies. Two independent reviewers selected and included all relevant articles based on the chosen search criteria to minimize bias risk. Currently available treatments for neurosurgical pain management include anticonvulsants, corticosteroids, NSAIDs, anti-inflammatory drugs, NMDA receptor antagonists, local anesthetics, nerve blocks, scalp blocks, and neuromuscular blocks. While more information is needed on the use of non-opioid pain management, the present literature provides potential evidence of its efficacy amongst the CM patient population, on account of the success that non-opioid pain management has demonstrated within other neurological pain syndromes. Further research into non-pharmacological pain management would also benefit the CM population and could be generalized to related conditions.

Amyotrophic Lateral Sclerosis Mimic Syndrome in a 24-Year-Old Man with Chiari 1 Malformation and Syringomyelia: A Clinical Case

Chiari 1 Malformation (CM1) is classically defined as a caudal displacement of the cerebellar tonsils through the foramen magnum into the spinal cord. Modern imaging techniques and experimental studies disclose a different etiology for the development of CM1, but the main etiology factor is a structural defect in the skull as a deformity or partial reduction, which push down the lower part of the brain and cause the cerebellum to compress into the spinal canal. CM1 is classified as a rare disease. CM1 can present with a wide variety of symptoms, also non-specific, with consequent controversies on diagnosis and surgical decision-making, particularly in asymptomatic or minimally symptomatic. Other disorders, such as syringomyelia (Syr), hydrocephalus, and craniocervical instability can be associated at the time of the diagnosis or appear secondarily. Therefore, CM1-related Syr is defined as a single or multiple fluid-filled cavities within the spinal cord and/or the bulb. A rare CM1-related disorder is syndrome of lateral amyotrophic sclerosis (ALS mimic syndrome). We present a unique clinical case of ALS mimic syndrome in a young man with CM1 and a huge singular syringomyelic cyst with a length from segment C2 to Th12. At the same time, the clinical picture showed upper hypotonic-atrophic paraparesis in the absence of motor disorders in the lower extremities. Interestingly, this patient did not have a disorder of superficial and deep types of sensitivity. This made it difficult to diagnose CM1. For a long time, the patient's symptoms were regarded as a manifestation of ALS, as an independent neurological disease, and not as a related disorder of CM1. Surgical treatment for CM1 was not effective, but it allowed to stabilize the course of CM1-related ALS mimic syndrome over the next two years.

Effectiveness of C1 Laminectomy for Chiari Malformation Type 1: Posterior Fossa Volume Expansion and Syrinx-Volume Decrease Rate

PURPOSE

This study aimed to analyze the effect of foramen magnum decompression with C1 laminectomy (C1L) for Chiari malformation type 1 (CM-1) in terms of improving clinical symptoms, expanding posterior fossa volume, and decreasing syrinx volume.

MATERIALS AND METHODS

Between January 2007 and June 2019, 107 patients with CM-1 were included. The median patient age was 13±13 years (range: 9 months-60 years), female-to-male ratio was 1:1, and average length of tonsil herniation was 13±5 mm (range: 5-24 mm). Surgical techniques were divided into four groups based on duraplasty or C1L usage. Among the study subjects, 38 patients underwent duraplasty and had their syrinx volumes measured separately on serial magnetic resonance imaging. A three-dimensional visualization software was used to evaluate the syrinx-volume decrease rate.

RESULTS

Bony decompression exhibited a mere 20% volume expansion of the lower-half posterior fossa. C1L offered a 3% additional volume expansion, which rose to 5% when duraplasty was added (p=0.029). There were no significant differences in complication rate when C1L was combined with duraplasty (p=0.526). Syrinx volumes were analyzed in 38 patients who had undergone duraplasty. Among them, 28 patients who had undergone duraplasty without C1L demonstrated a 5.9% monthly decrease in syrinx volume, which was 7.5% in the remaining 10 patients with C1L (p=0.040).

CONCLUSION

C1L was effective in increasing posterior fossa volume expansion, both with and without duraplasty. A more rapid decrease in syrinx volume occurred when C1L was combined with duraplasty.

Surgical outcomes of calvaria reconstruction in cranial pansynostosis associated with Arnold-Chiari type 1.5 malformation, a case report

A 6-year-old girl with persistent headaches and the visual problem was diagnosed as a delayed onset cranial pansynostosis with concurrent type 1.5 Arnold-Chiari malformation. She underwent multi-sutural reconstructive surgery and followed. The headache was greatly decreased and tonsillar-brain stem herniation and syrinx were resolved.

Potential association among posterior fossa bony volume and crowdedness, tonsillar hernia, syringomyelia, and CSF dynamics at the craniocervical junction in Chiari malformation type I

Objective

The characteristic morphological parameters (bony posterior fossa volume (bony-PFV), posterior fossa crowdness, cerebellar tonsillar hernia, and syringomyelia) and CSF dynamics parameters at the craniocervical junction (CVJ) in Chiari malformation type I (CMI) were measured. The potential association between these characteristic morphologies and CSF dynamics at CVJ was analyzed.

Methods

A total of 46 cases of control subjects and 48 patients with CMI underwent computed tomography and phase-contrast magnetic resonance imaging. Seven morphovolumetric measures and four CSF dynamics at CVJ measures were performed. The CMI cohort was further divided into "syringomyelia" and "non-syringomyelia" subgroups. All the measured parameters were analyzed by the Pearson correlation.

Results

Compared with the control, the posterior cranial fossa (PCF) area, bony-PFV, and CSF net flow were significantly smaller (P < 0.001) in the CMI group. Otherwise, the PCF crowdedness index (PCF CI, P < 0.001) and the peak velocity of CSF (P < 0.05) were significantly larger in the CMI cohort. The mean velocity (MV) was faster in patients with CMI with syringomyelia (P < 0.05). In the correlation analysis, the degree of cerebellar tonsillar hernia was correlated with PCF CI (R = 0.319, P < 0.05), MV (R = -0.303, P < 0.05), and the net flow of CSF (R = -0.300, P < 0.05). The Vaquero index was well correlated with the bony-PFV (R= -0.384, P < 0.05), MV (R = 0.326, P < 0.05), and the net flow of CSF (R = 0.505, P < 0.05).

Conclusion

The bony-PFV in patients with CMI was smaller, and the MV was faster in CMI with syringomyelia. Cerebellar subtonsillar hernia and syringomyelia are independent indicators for evaluating CMI. Subcerebellar tonsillar hernia was associated with PCF crowdedness, MV, and the net flow of CSF at CVJ, while syringomyelia was associated with bony-PFV, MV, and the net flow of CSF at the CVJ. Thus, the bony-PFV, PCF crowdedness, and the degree of CSF patency should also be one of the indicators of CMI evaluation.

Preoperative assessment of dominant occipital sinus in patients with Chiari malformation type I: anatomical variations and implications for preventing potentially life-threatening surgical complications

OBJECTIVE

The surgical treatment of Chiari malformation type I (CM-I) frequently involves dural incision at the posterior cranial fossa. In cases of persistent patent occipital sinus (OS), the sinus is usually obliterated and divided. However, there are some patients whose OS is prominent and requires crucial modification of the operative planning to avoid potentially life-threatening massive hemorrhage and disturbance of cerebral venous circulation. In the present study, the anatomical variations of the dominant OS in patients with CM-I were analyzed and the authors attempted to develop treatment recommendations for patients with CM-I with dominant OS.

METHODS

The study included 213 patients with CM-I who underwent MR venography (MRV) prior to surgical treatment. OS dominance was assessed using 2D time-of-flight MRV or 3D phase-contrast MRV. Particular attention was paid to the pattern of venous outflow channels. The characteristics of the patients with dominant OS and the surgical outcomes were retrospectively reviewed.

RESULTS

Dominant OS was identified in 7 patients (3.3%). The age in those with dominant OS was significantly younger than in those without (p = 0.0202). The incidence of concurrent scoliosis in the patients with dominant OS was significantly higher than in those without (p = 0.0366). All the dominant OSs were found to be of the oblique type. Unilateral oblique OS (OOS) with normal ipsilateral transverse sinus (TS) and hypoplastic contralateral TS was found in 2 patients (0.9%). The authors found 1 patient each (0.5%) who had unilateral OOS with hypoplastic ipsilateral TS and normal contralateral TS, unilateral OOS with bilateral hypoplastic TSs, and bilateral OOSs with bilateral normal TSs. Bilateral OOSs with bilateral hypoplastic TSs were found in 2 patients (0.9%). All these patients had syringomyelia. Instead of performing Y-shaped dural incision and duraplasty, surgical procedures were modified depending on the types of the OOSs to preserve their venous drainage routes. Although massive bleeding from the dominant OS during dural incision occurred in 1 patient, none suffered neurological deterioration. The syrinx volume decreased in all but 1 of the patients postoperatively.

CONCLUSIONS

Assessment of the venous drainage pattern using MRV is indispensable for safe surgical treatment in patients with CM-I. The surgical procedure should be modified based on the type of dominant OS to minimize the surgical risks.

Progressive Flaccid Paraplegia in a Toddler due to Chiari Type I Malformation Complicated with Hydrocephalus and Syringomyelia. A Case Report

Chiari malformation is a clinico-radiological entity defined by herniation of rhombencephalic structures through the foramen magnum. The most common type, Chiari I, involves herniation of the cerebellar tonsils specifically. We present the case of a 2-year-old with three weeks of progressive bilateral leg weakness, absent reflexes, and the inability to walk. The patient was found to have Chiari I with hydrocephalus and syringomyelia. This is the youngest patient reported in the literature presenting with a clinical picture of spinal shock. Early recognition of this entity allows for proper treatment and improved outcomes.

Charcot arthropathy of elbow due to syringomyelia: a case series and systematic review of literature

Syringomyelia is an important etiology of Charcot arthropathy of the elbow. We present five interesting patients, along with a systematic literature review summarizing the clinical profile and management of syringomyelia-induced Charcot arthropathy of the elbow. PUBMED, SCOPUS, EMBASE, and Science Direct databases were screened for English articles published between 1980 and 2022 using the search query: "Syringomyelia" AND "elbow" AND ("arthropathy" OR "neuropathic" OR "Charcot"). Articles without full text and/or lack of conclusive evidence of elbow arthropathy due to syringomyelia were excluded. The reference lists of the selected articles were reviewed to identify additional articles describing syringomyelia-induced Charcot arthropathy of the elbow. All five patients in the current series had elbow arthritis with variable motor weakness and dissociated sensory loss. The literature review included 31 reports (45 patients) and five patients from our center (n = 50). The median age at presentation was 45 (13-77) years. The median duration of arthropathy was 24 (0.5-180) months. Thirty-three patients had isolated elbow arthropathies. The other joints affected included the shoulder (n = 13), wrist (n = 7), metacarpophalangeal joints (n = 3), and interphalangeal joints (n = 1). Chiari malformations were present in 33 (66%) patients. Sensory deficits, motor deficits, and ulnar neuropathies were described in 36 (72%), 31 (62%), and 14 (28%) patients, respectively. Surgical decompression for syringomyelia was performed in 13 (26%) patients. The presence of dissociated sensory loss, with or without motor weakness, is key to the suspicion of syringomyelia-induced Charcot arthropathy of elbow. Chiari malformation and ulnar neuropathy are frequently associated with this condition. Key Points • Charcot arthropathy of elbow is not so uncommon as believed • Syringomyelia is an important etiology of Charcot arthropathy of elbow • Therefore, all patients with elbow arthropathy of unknown etiology must be evaluated for dissociative sensory loss • Chiari malformation and ulnar neuropathy are commonly associated with syringomyelia-induced Charcot arthropathy of elbow joint.

Impact of sleep-disordered breathing on the management of children with Chiari malformation type I

OBJECTIVES

Children with Chiari malformation type I (CM-I) have an increased risk of sleep apnea. The aim of the study was to describe the management of CM-I patients in relation to symptoms, magnetic resonance imaging (MRI) findings and sleep apnea syndrome (SAS).

METHODS

We performed a retrospective analysis of clinical charts of all 57 CM-I patients seen between September 2013 and April 2017.

RESULTS

A total of 45 patients had isolated CM-I or associated co-morbidity (CM-Iia), 5 had craniosynostosis (CM-Ics), and 7 a polymalformative syndrome (CM-Ipm). The prevalence of SAS, defined as an apnea-hypopnea index >1 event/h, was high in CM-I ranging from 50% to 80% according to the CM-I group. The prevalence of central sleep apnea (CSA) was low, with 5 (9%) patients having CSA and only 3 patients with CM-Iia having isolated CSA. A total of 17 patients (30%) had foramen magnum decompression (FMD). Neither positive symptoms of CM-I nor MRI findings alone, nor both combined were good indicators for FMD. No correlation was observed between the cerebellar tonsil descent and SAS in CM-I. But all 5 patients with CSA had a FMD. The combination of MRI findings and/or symptoms of CM-I together with moderate-to-severe SAS best discriminated patients who needed a FMD.

CONCLUSION

Our findings highlight the importance of a combined evaluation of symptoms, MRI and polygraphy results in the management of CM-I patients.

Assessment of neuromonitoring use and postoperative readmission rates in pediatric Chiari I malformation with syrinx

INTRODUCTION

While operative intervention for Chiari malformation type I (CMI) with syringomyelia is well established, there is limited data on outcomes of intraoperative neuromonitoring (IONM). This study sought to explore differences in procedural characteristics and their effects on postoperative readmission rates.

METHODS

The Nationwide Readmission Database was queried from 2010 to 2014 for patients ≤ 18 years of age with CMI and syringomyelia who underwent cranial decompression or spinal decompression. Demographics, hospital characteristics, and outcomes were analyzed.

RESULTS

Over the 5-year period, 2789 patients were identified that underwent operative treatment for CMI with syringomyelia. Mean age was 10 ± 4 years with 55% female. During their index hospitalization 14% of the patients had IONM. Patients receiving IONM had no significant difference in Charleston Comorbidity Index ≥ 1 (16% vs. 15% without, p = 0.774). IONM was more often used in those with private insurance (63% vs. 58% without, p = 0.0004) and less likely in those with Medicaid (29% vs. 37% without, p = 0.004). Patients receiving IONM were more likely to have a postoperative complication (23% vs 17%, p = 0.004) and were more likely to have hospital lengths of stay > 7 days (9% vs. 5% without, p = 0.005). Readmission rates for CMI were 9% within 30 days and 15% within the year. The majority (89%) of readmissions were unplanned. 25% of readmissions were for infection and 27% of readmissions underwent a CMI reoperation. The 30-day readmission rate was higher for those with IONM (12% vs. 8% without, p = 0.010). Median cost for hospitalization was significantly higher for patients with IONM ($26,663 ($16,933-34,397)) vs. those without ($14,577 ($11,538-18,392)), p < 0.001.

CONCLUSION

The use of intraoperative neuromonitoring for operative repair of CMI is associated with higher postoperative complications and readmissions. In addition, there are disparities in its use and increased cost to the healthcare system. Further studies are needed to elucidate the factors underlying this association.

Pediatric Chiari I malformation: novel and traditional measurements associated with syrinx and surgery

PURPOSE

Multiple imaging parameters have been examined to estimate the presence of syrinx and the need for surgery in Chiari I patients (CM1); however, no consistent or definitive criteria have been proposed. The objective of this study was to review existing and identify novel radiological and clinical characteristics of CM1 patients that associate syrinx development and surgical intervention.

METHODS

Patients with Chiari I malformation diagnosed on imaging between 0 and 18 years were retrospectively reviewed from January 1, 2007 to February 12, 2020. Participants were included if they had a baseline MRI of the head and spine prior to surgical intervention if required. Forty age-matched controls with cranial imaging were identified for comparison. Imaging parameters and clinical symptoms were recorded.

RESULTS

A total of 122 CM1 patients were included in this study. Of the 122 patients, 28 (23%) had syrinx, and 27 (22%) had surgery. The following imaging parameters associated with syrinx and surgical intervention were identified: midbrain length (P < 0.001; P = 0.032), the obex position (P = 0.002; P < 0.001) and medullary kinking (P = 0.041; P < 0.001). Among the clinical features, the presence of overall pain (P = 0.017; P = 0.042), neck pain (P = 0.005; P = 0.027), and sensory dysfunction (P < 0.001) were found to be strongly associated with syrinx and surgery.

CONCLUSION

While further investigation is needed, these specific radiological and clinical parameters should be considered when evaluating CM1 patients and may be used to guide further management.

Spontaneous resolution of syringomyelia following pregnancy and parturition in a patient with type I chiari malformation: A case and systematic review

BACKGROUND

Spontaneous resolution of syringomyelia has rarely been reported in the literature. Rarer still are cases wherein this process is associated with pregnancy and parturition. We review theories on syringomyelia development and spontaneous resolution to better understand the role pregnancy and parturition may play in both processes.

METHODS

We present a 30-year-old female with MRI-confirmed spontaneous syrinx regression following caesarean delivery of a full-term pregnancy. We additionally review the literature to identify previously reported cases of spontaneous syrinx regression both independent of and associated with pregnancy.

RESULTS

Including the present case, 39 cases describing spontaneous regression of syringomyelia have been reported in the literature, of which only four are associated with pregnancy and parturition. 75% of all reported cases were associated with type I Chiari malformation, though several disorders of the craniocervical junction and spinal canal were implicated. Complete syrinx regression was achieved in 33.3% of cases and 5% of cases described recurrence of syringomyelia following the spontaneous resolution.

CONCLUSION

Syringomyelia likely develops due to disturbance of the physiologic flow of cerebrospinal fluid around the craniocervical junction and the obex. Several mechanisms including fissuring of the spinal cord parenchyma and reduction of subarachnoid scarring are likely involved in this process. In the setting of pregnancy, additional mechanisms surrounding the increased intraabdominal forces imparted by a growing fetus, Valsalva-like strain experienced during labor, and hemodynamic changes that occur to accommodate gestation are likely implicated. Nevertheless, patients should continue to be monitored periodically for syrinx recurrence.

Neurological deterioration after posterior fossa decompression for adult syringomyelia: Proposal for a summarized treatment algorithm

Background

Patients with syringomyelia who present with new neurological symptoms after posterior fossa decompression (PFD) are not uncommon. However, systematic reports on different pathologies are few in the literature.

Objective

The purpose of this study was to summarize our experience for failed PFD.

Methods

Between January 2015 and December 2019, 85 consecutive failed PFD patients were identified. The neurological courses were summarized with Klekamp J (KJ) or mJOA score system for all patients. Long-term results were summarized with Kaplan-Meier method.

Results

Twenty-eight consecutive patients underwent FMDD (Foramen magnum and foramen of Magendie dredging) (Group I), extradural PFD and manipulation of tonsil was significantly associated with lower failure rates. Twenty patients underwent craniocervical fixation (Group II), nine underwent local spinal segment decompression (Group III), six underwent CSF diversion procedures, and one were treated for persistent pain by radiofrequency. Neuropathic pain was most significantly improved in Group I while swallowing improved in Group II within 1 year after the surgery. In the long term, late postoperative deterioration-free possibility in Group II was better than in Group I. All patients in Group III improved (P = 0.0088). Six cases of CSF diversion procedures were relieved in a short time. Pain in one patient persisted after PFD, and trial of radiofrequency failed.

Conclusion

Not only does the recurrent cerebrospinal fluid flow obstruct the foramen magnum, but also spinal pathologies and craniocervical instabilities may occur. This study provides the largest summarized clinical experience that may assist surgeons with different therapeutic decisions for failed PFD.

Sleep-disordered breathing in patients with Chiari malformation type II: a case-control study and review of the literature

STUDY OBJECTIVES

The main aim was to evaluate the prevalence of sleep-disordered breathing (SDB) in patients with Chiari II malformation (CM-II). The secondary objectives were to evaluate the association between SDB, morphological abnormalities, and neurological symptoms and to review the literature on patients with SDB and CM-II.

METHODS

The study has a cross-sectional, case-control design. Patients with CM-II (patients) were compared to control patients referred for clinical polysomnography in the Sleep Medicine Unit, matched for age and sex. All patients underwent brain and spinal cord magnetic resonance imaging, and polysomnography was conducted for all participants. A review of the literature about SDB in patients with CM-II was performed.

RESULTS

Forty patients were included (20 patients vs 20 control patients). SDB was identified in 45% of patients, a significantly higher prevalence compared to control patients. Three patients presented with purely obstructive SDB, 3 patients with purely central SDB, and 3 patients with both obstructive and central SDB. Compared with control patients, patients with CM-II showed a higher oxygen desaturation index (median: CM-II, 3.7; interquartile range, 1.6-19.5; control patients: 1.1; interquartile range, 0.3-3.2) and obstructive apnea-hypopnea index (median: CM-II, 1.5; interquartile range, 0.5-5.1; control patients, 0.1; interquartile range, 0.0-0.7). A logistic regression showed that the risk of developing SDB in patients affected by CM-II was 14.7 times higher than in the control population.

CONCLUSIONS

Our study and literature review showed a high prevalence of SDB in patients with CM-II. These patients are often asymptomatic at diagnosis, suggesting that PSG should be routinely provided in this population.

CITATION

Lazzareschi I, Curatola A, Massimi L, et al. Sleep-disordered breathing in patients with Chiari malformation type II: a case-control study and review of the literature. J Clin Sleep Med. 2022;18(9):2143-2154.

Quantifying cerebrospinal fluid dynamics: A review of human neuroimaging contributions to CSF physiology and neurodegenerative disease

Cerebrospinal fluid (CSF), predominantly produced in the ventricles and circulating throughout the brain and spinal cord, is a key protective mechanism of the central nervous system (CNS). Physical cushioning, nutrient delivery, metabolic waste, including protein clearance, are key functions of the CSF in humans. CSF volume and flow dynamics regulate intracranial pressure and are fundamental to diagnosing disorders including normal pressure hydrocephalus, intracranial hypotension, CSF leaks, and possibly Alzheimer's disease (AD). The ability of CSF to clear normal and pathological proteins, such as amyloid-beta (Aβ), tau, alpha synuclein and others, implicates it production, circulation, and composition, in many neuropathologies. Several neuroimaging modalities have been developed to probe CSF fluid dynamics and better relate CSF volume and flow to anatomy and clinical conditions. Approaches include 2-photon microscopic techniques, MRI (tracer-based, gadolinium contrast, endogenous phase-contrast), and dynamic positron emission tomography (PET) using existing approved radiotracers. Here, we discuss CSF flow neuroimaging, from animal models to recent clinical-research advances, summarizing current endeavors to quantify and map CSF flow with implications towards pathophysiology, new biomarkers, and treatments of neurological diseases.

Acquired Chiari malformation Type I and holocord syringomyelia associated with a high-flow supratentorial fistulous arteriovenous malformations: A case report and literature review

Background:

Chiari malformation Type I (CMI) is generally considered a congenital lesion and typically associated with syringomyelia. Acquired CMI or adult Chiari malformation caused by intracranial mass is extremely rare. Brain arteriovenous malformations (AVMs) are characteristically symptomatic due to seizure, intracranial hemorrhage, or neurological deficit. We report an extremely rare case of an acquired CMI and extensive syringomyelia associated with a large supratentorial AVM.

Case Description:

A 35-year-old woman was referred to our institute after a diagnosis of CMI and extensive syringomyelia from whole-spine magnetic resonance imaging (MRI) due to complaining of low back pain radiating to the right leg for the past 1 month. She had intermittent headache for 2 years. The patient underwent suboccipital decompression and C1 laminectomy followed by duraplasty. Two months later, she developed severe right-sided sciatic pain and complete right foot drop. Follow-up MRI revealed progressive enlargement of a syrinx cavity at the lower spinal cord and a large right parieto-occipital AVM with markedly dilated cortical draining veins and diffuse engorgement of dural venous sinuses was detected. This AVM supplied mainly by enlarged cortical branches of the right middle cerebral artery and posterior cerebral artery with multiple dural supplies. Endovascular treatment of a high-flow fistulous AVM was successfully performed with N-butyl cyanoacrylate (NBCA) through the hypertrophic branches of the right middle cerebral artery. Four months after embolization, the patient had recovered completely from the right foot drop. Further staged embolization was planned to reduce the size and flow of the AVM before stereotactic radiosurgery. However, the patient was lost to follow-up due to financial reason. One year later, she developed sudden severe headache followed by alteration of conscious due to intraventricular hemorrhage from the AVM, leading to obstructive hydrocephalus requiring cerebrospinal fluid diversion. During a period of 2 years, the patient underwent several staged embolization with NBCA and Onyx. Final cerebral angiography after embolization demonstrated a significant reduction in size and flow of the brain AVM. A control whole-spine MRI revealed a significant reduction in syrinx size. At the end of embolization, the patient had no neurological deficit. However, she had suffered from persistent central neuropathic pain at the right lower extremity. The AVM remnant was further treated by stereotactic radiosurgery.

Conclusion:

Increased cerebral venous hypertension secondary to a high-flow supratentorial AVM leading to posterior fossa venous hypertension may play a major role in the pathogenesis of CMI, induced the formation of syringomyelia. Endovascular treatment of brain AVM, the underlying cause of CMI, resulted in a significant reduction of the size of the syrinx. The need for cranial imaging in initial evaluation of cases with adult Chiari malformation is important.

Case Report: Downbeat Nystagmus Due to Epidural Puncture during Labor with Undiagnosed Arnold Chiari Malformation

SIGNIFICANCE

Epidural anesthesia is a safe procedure used in pregnant patients during labor. However, caution should be exercised in those patients that have concurrent Arnold Chiari malformation.

PURPOSE

To report a rare and atypical presentation of downbeat nystagmus, in a pregnant patient with Arnold Chiari malformation type 1 (ACM1), secondary to accidental dural puncture.

CASE REPORT

A 31-year-old African American female presented with a chief complaint of decreased vision and oscillopsia that occurred after giving birth, six months earlier. Her medical history prior to presentation was unremarkable. Her delivery was typical; however, the patient did receive epidural anesthesia which resulted in a dural puncture. The patient noted her symptoms a few days after delivery. Upon examination, persistent down beat nystagmus was noted in both eyes. Magnetic resonance imaging revealed a 2.5 cm inferior displacement of the cerebellar tonsils below the foramen magnum consistent with ACM1. The patient was referred to neurosurgery for posterior fossa decompression. However, surgery was deferred until appropriate weight reduction could be achieved. Follow-up examination six months later revealed no change in her clinical findings.

CONCLUSIONS

This case report highlights an atypical presentation of downbeat nystagmus secondary to an accidental dural puncture in a pregnant patient with undiagnosed ACM1. Clinicians should consider the importance of considering ocular complications that can occur in pregnant patients with ACM1. Questioning of women who have recently given birth about epidural anesthesia should be considered with an acute presentation of downbeat-nystagmus.

A new concept of the fiber composition of cervical spinal dura mater: an investigation utilizing the P45 sheet plastination technique

Purpose

Few reports have been published regarding the microanatomy of the dura mater located at the craniovertebral junction (CVJ). In clinic, the precise microanatomy of the CVJ dura mater would be taken into account, for reducing surgical complications and ineffective surgical outcomes. The main objective of the present investigation was to further elucidate the fiber composition and sources of the cervical spinal dura mater.

Methods

The formalin-fixed adult head and neck specimens (n = 21) were obtained and P45 plastinated section method was utilized for the present study. The fibers of the upper cervical spinal dura mater (SDM) were examined in the P45 sagittal sections in the CVJ area. All photographic documentation was performed via a Canon EOS 7D Mark camera.

Results

The posterior wall of the SDM sac at CVJ was found to be composed of stratified fibers, which are derived from three sources: the cerebral dura mater, the occipital periosteum, and the myodural bridge (MDB). The proper layer of the cerebral dura mater passes over the brim of the foramen magnum and enters the vertebral canal to form the inner layer of the SDM, and the fibers originating from the periosteum of the brim of the foramen magnum form the middle layer. The fibers of the MDB are inserted into the SDM and form its outer layer. It was found that the total number of fibers from each origin varied in humans.

Conclusion

At the CVJ, the posterior wall of the SDM is a multi-layered structure composed of three different originated fibers. The cerebral dura mater, the periosteum located at the brim of the foramen magnum, and MDB contribute to the formation of the SDM. The present study would be beneficial to the choice of surgical approach at the CVJ and the protection of the SDB.

Significance of Pseudomeningocele After Decompressive Surgery for Chiari I Malformation

Background

Pseudomeningoceles (PMCs) as abnormal collections of cerebrospinal fluid are quite common findings on follow-up MRI after Chiari decompression surgery (CDS). However, the importance of their identification has not been truly determined, especially when PMCs are described occasionally in the process of radiological follow-up. We retrospectively analyzed surgical outcomes and imaging findings after CDS depending upon the occurrence and thickness of PMCs.

Methods

A total of 76 adult patients who underwent CDS were analyzed. The clinical and radiological outcomes of patients with a pseudomeningocele (wPMC) were evaluated and compared to those of patients without a pseudomeningocele (w/oPMC). Radiological morphometric measurements were performed and compared between groups. Comparisons of the maximal PMC thickness were made within the wPMC group.

Results

PMCs were recognized in 27 (35.5%) patients, of whom 3 (11.1%) required reoperation. Differences in satisfactory result rates regarding gestalt assessment and Chicago Chiari Outcome Scale were statistically insignificant between the w/oPMC and wPMC groups (p = 1 and p = 0.56, respectively). The postoperative syringomyelia decrease and cerebellar tonsil elevation were similar between the groups (p = 1 and p = 0.74, respectively) in the long-term follow-up. Additionally, the clinical or radiological outcomes with radiological details were not related to PMC thickness in the long-term follow-up. However, radiological details showed the cooccurrence of PMCs with a postsurgical of cerebello-tentorial distance increase (p &lt; 0.05), basion-pontomedullary sulcus distance decrease (p &lt; 0.05) and tonsillo-graft distance decrease (p &lt; 0.05).

Conclusions

We found no significant relationships between PMC presence or thickness and clinical or radiological outcomes. However, postoperative changes within the posterior fossa associated with PMCs resemble brain sagging, which occurs in intracranial hypotension. Therefore, extradural cerebrospinal fluid escape may also be responsible for symptoms in some patients with PMCs after CDS.

Care for Chiari malformation type I: the role of socioeconomic disadvantage and race

OBJECTIVE

There is little research on the effect of social determinants of health on Chiari malformation type I (CM-I). The authors analyzed data on all children evaluated for CM-I at a single institution to assess how socioeconomic factors and race affect the surgical treatment of this population.

METHODS

Medical records of patients treated for CM-I at the authors' institution between 1992 and 2017 were reviewed. Area Deprivation Index (ADI) and Rural-Urban Commuting Area (RUCA) codes for each patient were used to measure neighborhood disadvantage. Non-Hispanic White patients were compared to non-White patients and Hispanic patients of any race (grouped together as non-White in this study) in terms of insurance status, ADI, and RUCA. Patients with initially benign CM-I, defined as not having undergone surgery within 9 months of their initial visit, were then stratified by having delayed symptom presentation or not, and compared on these same measures.

RESULTS

The sample included 665 patients with CM-I: 82% non-Hispanic White and 18% non-White. The non-White patients were more likely to reside in disadvantaged (OR 3.4, p < 0.001) and urban (OR 4.66, p < 0.001) neighborhoods and to have public health insurance (OR 3.11, p < 0.001). More than one-quarter (29%) of patients underwent surgery. The non-White and non-Hispanic White patients had similar surgery rates (29.5% vs 28.9%, p = 0.895) at similar ages (8.8 vs 9.7 years, p = 0.406). There were no differences by race/ethnicity for symptoms at presentation. Surgical and nonsurgical patients had similar ADI scores (3.9 vs 4.2, p = 0.194), RUCA scores (2.1 vs 2.3, p = 0.252), and private health insurance rates (73.6% vs 74.2%, p = 0.878). A total of 153 patients underwent surgery within 9 months of their initial visit. The remaining 512 were deemed to have benign CM-I. Of these, 40 (7.8%) underwent decompression surgery for delayed symptom presentation. Patients with delayed symptom presentation were from less disadvantaged (ADI 3.2 vs 4.2; p = 0.025) and less rural (RUCA 1.8 vs 2.3; p = 0.023) areas than those who never underwent surgery.

CONCLUSIONS

Although non-White patients were more likely to be socioeconomically disadvantaged, race and socioeconomic disadvantage were not associated with undergoing surgical treatment. However, among patients with benign CM-I, those undergoing decompression for delayed symptom presentation resided in more affluent and urban areas.

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.

•

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

•

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

•

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

Occipitocervical fusion as treatment of instability in Chiari malformation

Introduction. Occipitocervical (OC) fusion is a method for fixation of the OC junction when there is instability of that segment. Arnold Chiari malformation is a congenital disorder where cerebellar tonsils descend through the foramen magnum, which can lead to cervicomedular compression and formation of syrinx. While treating this condition, for the purpose of decompression, the foramen magnum is expanded which can potentially harm the stability of the OC junction. Case outline. We are presenting the case of a 16 year old female who was surgically treated (suboccipital craniectomy and decompression) because of Arnold Chiari malformation type I. One-year post-op multislice computed tomography verified a slight enlargement of basion-axial and basion-dens intervals, with signs of spinal cord compression. Surgery was performed - occipitocervical fusion, canal decompression on C1 and C2 levels with a plate on occipital bone and screws placed in the third, fourth, and fifth cervical vertebra. Conclusion. Occipitocervical fusion is a complex surgical procedure (vital neurovascular structures), but it is a reliable method for treatment of instability of the OC junction.

The surgical resection of dysplastic cerebellar gangliocytoma assisted by intraoperative sonography: illustrative case

BACKGROUND

Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease) is an extremely rare, slow-growing hereditary mass lesion that is mainly characterized by both specific neuroradiological features and secondary hydrocephalus. Patients may present with symptoms of cerebellar mass lesion and increased intracranial pressure. As an important part of Cowden syndrome, Lhermitte-Duclos disease in adults is typically marked by PTEN gene mutation.

OBSERVATIONS

The clinical management of a 31-year-old woman who suffered Lhermitte-Duclos disease was introduced in this case report. Subtotal resection was performed with the assistance of intraoperative sonography to relieve obstructive hydrocephalus, and prophylactic C1 laminectomy was performed to prevent possible postoperative progression of the residual lesion. Perioperative care and surgical process were clearly revealed in an accompanying video. Intraoperative sonography of Lhermitte-Duclos disease presents hyperechoic distorted thickening cortices surrounded by hypoechoic edema belt. The patient did not report any significant neurological complications or sequelae after the lesion resection.

LESSONS

The authors first reported the use of intraoperative sonography in resection of adult-onset Lhermitte-Duclos disease. Hopefully, the educative case report can provide a feasible experience in the diagnosis and treatment of Lhermitte-Duclos disease.

Vertigo: Streamlining the Evaluation through Symptom Localization

Vertigo is defined as the illusion of internal or external motion. The evaluation of a patient with vertigo in the primary care setting should not necessarily focus on providing a specific diagnosis. Rather, the physician should aim to localize the lesion. This practice streamlines the workup of patients. This article provides detailed information regarding appropriate organ system-based clinical history and the clinical workup of vertigo. Additional signs and symptoms that can facilitate appropriate referral and treatment are highlighted. Although disorder-specific treatments exist the mainstay of therapy for vertigo-induced pathology is physical therapy.

Inpatient outcomes of posterior fossa decompression with or without duraplasty for Chiari malformation type I

OBJECTIVE

Chiari malformation type 1 (CM-1) is a congenital neurologic condition in which the cerebellar tonsils herniate below the foramen magnum, resulting in symptoms such as headache and neck pain. Two common surgical treatment approaches are posterior fossa decompression with (PFDD) and without duraplasty (PFD). Previous single-center studies have demonstrated increased neurologic complications after PFDD compared to PFD. The goal of this study is to determine differences in inpatient complications and hospitalization data among patients treated with these surgical techniques using a nationwide sample.

METHODS

The National Inpatient Sample (NIS) was queried for years 2012-2015 for all patients with a primary diagnosis of CM-1 who underwent PFD or PFDD. Differences in baseline demographics and comorbidities were accounted for in subsequent analysis using propensity score matching. Hospitalization measures and inpatient complications of the two cohorts were compared using Chi-squared tests and t-tests when appropriate.

RESULTS

A total of 2395 patients with CM-1 were included in this study, with 750 (31.3%) undergoing PFD and 1645 (68.7%) undergoing PFDD. PFDD was associated with higher total hospital costs than PFD. There were no significant differences in other hospitalization or discharge data, non-neurologic complications, or CNS complications (CSF leak, pseudomeningocele, abscess, meningitis, stroke) between the two surgical groups.

CONCLUSIONS

This study represents the largest national analysis to date of adult CM-1 patients undergoing PFD or PFDD. Our findings suggest that whether the decision is made to perform the less invasive PFD or more invasive PFDD, inpatient complications and hospitalization data will not significantly differ.

One-Year Outcomes of Chiari Type 1 Malformation and Syringomyelia Treated With Posterior Fossa Decompression

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

The objective of this study was to evaluate posterior fossa structural differences between Chiari type 1 malformation with and without syringomyelia, and assess data of the improvement of syringomyelia after different surgical options.

SUMMARY OF BACKGROUND DATA

Syringomyelia is among the most common concomitant complications of Chiari malformation (CM). However, posterior fossa decompression cannot definitely make the syringomyelia disappear even in the long term. Also, there are no universal criteria defining improvement in syrinx.

MATERIALS AND METHODS

All admitted CM patients at our institution from 2013 to 2018 with a 1-year follow-up were analyzed. Patients without syringomyelia were compared with those who had syringomyelia. Patients were divided into 3 groups according to the procedures performed: posterior fossa decompression versus posterior fossa decompression with duralplasty (PFDD) versus PFDD plus obex unblocking. Divergent prognosis of syringomyelia was defined as a 3-category ordinal variable. A multivariable ordinal regression model was used to estimate the relationship between patient variables and increased odds for better resolution of syringomyelia.

RESULTS

No significant linear difference in bony structure was found between syringomyelia and nonsyringomyelia patients. Among syringomyelia patients, the regression analysis demonstrated that patients with shorter posterior fossa height ( P =0.032), lower Pavlov ratio ( P =0.029), and obex unblocking (vs. PFDD, P <0.001; vs. posterior fossa decompression, P =0.037) were more likely to gain a better resolution of syringomyelia.

CONCLUSIONS

Syringomyelia of CM patients may not simply originate from single linear anatomic variation. Patients with shorter posterior fossa height and lower Pavlov ratio received better syringomyelia resolution. Also, unblocking the obex received better syringomyelia resolution compared with duraplasty alone and bony decompression alone with the avoidance of increased postoperative complications and worse clinical outcomes.

Type I Chiari Malformation Without Concomitant Bony Instability: Assessment of Different Surgical Procedures and Outcomes in 73 Patients

OBJECTIVE

Posterior fossa decompression is the treatment of choice in type 1 Chiari malformation (CM-1) without bony instability. Although surgical fixation has been recommended by a few authors recently, comparative studies to evaluate these treatment strategies using objective outcome tools are lacking.

METHODS

Seventy-three patients with pure CM-1 (posterior fossa bony decompression [PFBD], n = 21; posterior fossa bony and dural decompression [PFBDD], n = 40; and posterior fixation [PF], n = 12) underwent a postoperative outcome assessment using Chicago Chiari Outcome Score (CCOS). Logistic regression analysis detected predictors of an unfavorable outcome.

RESULTS

Minimally symptomatic patients generally underwent a PFBD while most of the clinically severe patients underwent a PFBDD (p = 0.049). The mean CCOS score at discharge was highest in the PF (12.0 ± 1.41) and lowest in PFBDD group (10.98 ± 1.73, p = 0.087). Patients with minimal preoperative clinical disease severity (adjusted odds ratio [AOR], 4.58; 95% confidence interval [CI], 1.29-16.31) and PFBDD (AOR, 7.56; 95% CI, 1.70-33.68) represented risks for an unfavorable short-term postoperative outcome. Though long-term outcomes (CCOS) did not differ among the 3 groups (p = 0.615), PFBD group showed the best long-term improvements (mean follow-up CCOS, 13.71 ± 0.95), PFBDD group improved to a comparable degree despite a poorer short-term outcome while PF had the lowest scores. Late deteriorations (n = 3, 4.1%) occurred in the PFBDD group.

CONCLUSION

Minimally symptomatic patients and PFBDD predict a poor short-term postoperative outcome. PFBD appears to be a durable procedure while PFBDD group is marred by complications and late deteriorations. PF does not provide any better results than posterior fossa decompression alone in the long run.

Utility of True Fast Imaging with Steady-State Precession in Detecting Arachnoid Veils of the Posterior Fossa

INTRODUCTION

Arachnoid membranes are well recognized as a cause of cerebrospinal fluid (CSF) flow impairment in disorders such as obstructive hydrocephalus and syringohydromyelia, but can be difficult to detect with standard noninvasive imaging techniques. True fast imaging with steady-state precession (TrueFISP) can exhibit brain pulsations and CSF dynamics with high spatiotemporal resolution. Here, we demonstrate the utility of this technique in the diagnosis and management of arachnoid membranes in the posterior fossa.

CASE PRESENTATIONS

Three symptomatic children underwent cine TrueFISP imaging for suspicion of CSF membranous obstruction. Whereas standard imaging failed to or did not clearly visualize the site of an obstructive lesion, preoperative TrueFISP identified a membrane in all 3 cases. The membranes were confirmed intraoperatively, and postoperative TrueFISP helped verify adequate marsupialization and recommunication of CSF flow. Two out of the 3 cases showed a decrease in cerebellar tonsillar pulsatility following surgery. All children showed symptomatic improvement.

CONCLUSION

TrueFISP is able to detect pulsatile arachnoid membranes responsible for CSF outflow obstruction that are otherwise difficult to visualize using standard imaging techniques. We advocate use of this technology in pre- and postsurgical decision-making as it provides a more representative image of posterior fossa pathology and contributes to our understanding of CSF flow dynamics. There is potential to use this technology to establish prognostic biomarkers for disorders of CSF hydrodynamics.

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.

The 270° Circumferential Microsurgical Decompression of the Foramen Magnum in Adult Chiari Malformation Type I: Single Surgeon Series of 130 Patients with Syringomyelia, Neurologic, and Headache Outcomes

OBJECTIVE

Chiari malformation type I (CM-I) is a craniocervical junction disorder associated with descent of the cerebellar tonsils >5 mm. The prevalence of CM-I is common, including 0.5%-3.5% in the general population, 0.56%-0.77% on magnetic resonance imaging, and 0.62% in anatomic dissection studies. We sought to measure our surgical outcomes related to resolution/improvement of headaches, neurologic outcomes, and syringomyelia compared with reported adult CM-I studies from 2000-2019.

METHODS

From December 2003 to June 2018, the first author (K.I.A.) performed 270° circumferential decompression on adult (>18 years) patients with CM-I. At admission and follow-up, all parameters were numerically evaluated; headaches were self-reported on the visual analog scale, neurologic condition was evaluated using Karnofsky Performance Status and European Myelopathy Score, and syrinx width (if present) was measured on magnetic resonance imaging by grades I-IV. All parameters were analyzed, compared, and statistically tested. We compared results with our previously reported and updated systematic review of operative adult CM-I studies (studies from 2000 to 2019).

RESULTS

In our series, 118/121 (98%) experienced headache improvements and 100% experienced neurologic improvements. Complete syrinx resolution was experienced by 35/43 (81%); 8 (19%) showed significant improvement. In data from reported studies (2000-2019), only 79% experienced headache resolution, 77% improvement of neurologic status, and 74% resolution/improvement of syrinx (mean).

CONCLUSIONS

Our modified 270° circumferential microsurgical foramen magnum decompression for adult CM-I appears to be beneficial in improvement of outcomes, namely in resolution of the syrinx, neurologic symptoms, and headaches. We also confirm the association of body mass index with CM-I. Further studies are needed to confirm our results.