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AJNR. American Journal of Neuroradiology Nov 2020Chiari 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... (Review)
Review
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.
Topics: Arnold-Chiari Malformation; Humans
PubMed: 32943418
DOI: 10.3174/ajnr.A6743 -
World Neurosurgery Jul 2023Patients with Chiari malformation (CM) associated with atlantoaxial dislocation (AAD) and basilar invagination (BI) may present with a small posterior cranial fossa, but...
OBJECTIVE
Patients with Chiari malformation (CM) associated with atlantoaxial dislocation (AAD) and basilar invagination (BI) may present with a small posterior cranial fossa, but data on the volumetric analysis are lacking. Additionally, whether additional foramen magnum decompression (FMD) is needed together with atlantoaxial fusion remains controversial. This study evaluated the volumetric alterations of the posterior cranial fossa in these patients and analyzed the radiological and clinical outcomes after posterior C1-C2 reduction and fixation plus C1 posterior arch resection.
METHODS
Thirty-two adult CM patients with AAD and BI (CM-AAD/BI group) and 21 AAD and BI patients without CM (AAD/BI-only group) who received posterior atlantoaxial fusion plus C1 posterior arch resection were retrospectively studied. The clinical and radiological outcomes and volumetric measurements of the posterior cranial fossa were evaluated.
RESULTS
The majority of CM-AAD/BI patients (94%) improved clinically and radiologically at 12 mo postoperatively, and none required additional FMD. Morphological analysis revealed a significant reduction in the bony posterior cranial fossa volumes of the CM-AAD/BI group (P < 0.01) and the AAD/BI-only group (P < 0.01) relative to those of the CM group. No significant differences were observed between the CM-AAD/BI and AAD/BI groups.
CONCLUSIONS
Compared with patients with simple CM, patients with AAD/BI with or without CM demonstrated a considerably and equally reduced bony posterior cranial fossa volume. No additional FMD is needed in the treatment of CM-AAD/BI patients after posterior reduction and fusion plus C1 posterior arch resection.
Topics: Adult; Humans; Retrospective Studies; Arnold-Chiari Malformation; Platybasia; Joint Dislocations; Atlanto-Axial Joint; Decompression, Surgical; Neck Injuries; Spinal Fusion
PubMed: 37087038
DOI: 10.1016/j.wneu.2023.04.064 -
Radiology Oct 2021Background Posterior fossa decompression (PFD) surgery is a treatment for Chiari malformation type I (CMI). The goals of surgery are to reduce cerebellar tonsillar...
Background Posterior fossa decompression (PFD) surgery is a treatment for Chiari malformation type I (CMI). The goals of surgery are to reduce cerebellar tonsillar crowding and restore posterior cerebral spinal fluid flow, but regional tissue biomechanics may also change. MRI-based displacement encoding with stimulated echoes (DENSE) can be used to assess neural tissue displacement. Purpose To assess neural tissue displacement by using DENSE MRI in participants with CMI before and after PFD surgery and examine associations between tissue displacement and symptoms. Materials and Methods In a prospective, HIPAA-compliant study of patients with CMI, midsagittal DENSE MRI was performed before and after PFD surgery between January 2017 and June 2020. Peak tissue displacement over the cardiac cycle was quantified in the cerebellum and brainstem, averaged over each structure, and compared before and after surgery. Paired tests and nonparametric Wilcoxon signed-rank tests were used to identify surgical changes in displacement, and Spearman correlations were determined between tissue displacement and presurgery symptoms. Results Twenty-three participants were included (mean age ± standard deviation, 37 years ± 10; 19 women). Spatially averaged (mean) peak tissue displacement demonstrated reductions of 46% (79/171 µm) within the cerebellum and 22% (46/210 µm) within the brainstem after surgery ( < .001). Maximum peak displacement, calculated within a circular 30-mm area, decreased by 64% (274/427 µm) in the cerebellum and 33% (100/300 µm) in the brainstem ( < .001). No significant associations were identified between tissue displacement and CMI symptoms ( < .74 and > .012 for all; Bonferroni-corrected = .0002). Conclusion Neural tissue displacement was reduced after posterior fossa decompression surgery, indicating that surgical intervention changes brain tissue biomechanics. For participants with Chiari malformation type I, no relationship was identified between presurgery tissue displacement and presurgical symptoms. © RSNA, 2021
Topics: Adult; Arnold-Chiari Malformation; Brain Stem; Cerebellum; Decompression, Surgical; Female; Humans; Magnetic Resonance Imaging; Male; Postoperative Complications; Prospective Studies
PubMed: 34313469
DOI: 10.1148/radiol.2021203036 -
Child's Nervous System : ChNS :... Jul 2021We present a rare case of an 8-year-old male with Klippel-Trenaunay syndrome (KTS) and a Chiari I malformation (CIM). Magnetic resonance imaging (MRI) to investigate... (Review)
Review
We present a rare case of an 8-year-old male with Klippel-Trenaunay syndrome (KTS) and a Chiari I malformation (CIM). Magnetic resonance imaging (MRI) to investigate facial asymmetry and speech delay at age two revealed CIM with cerebellar tonsils 1.3 cm below the foramen magnum without syringomyelia. The patient underwent a craniectomy and posterior fossa decompression with C1 laminectomy. While gene sequencing determined the patient was negative for the PIK3CA gene mutation, the patient's clinical history strongly suggests KTS. He has hemihypertrophy, leg length discrepancy, hemangiomas and pigmentary mosaicism along the upper and lower extremities, heart murmur, chronic low heart rate, recurrent hip pain, and mild scoliosis. Neurodevelopmental concerns include difficulty reading, attention deficit hyperactivity disorder (ADHD), anxiety, and difficulty running and going downstairs. His most recent MRI shows good decompression at the cervicomedullary junction, global cerebrospinal fluid (CSF) flow, and less peg-like cerebellar tonsils. Also noted were two intravertebral hemangiomas at T5 and T6. While the patient's speech has improved, there is still difficulty with the expressive language. He still has mild delays, runs slowly, and does not alternate feet when climbing stairs. The patient is being followed by multiple specialists including neurology, hematology-oncology, genetics, orthopedic surgery, and developmental pediatrics.
Topics: Arnold-Chiari Malformation; Child; Foramen Magnum; Humans; Klippel-Trenaunay-Weber Syndrome; Laminectomy; Magnetic Resonance Imaging; Male; Syringomyelia
PubMed: 33492467
DOI: 10.1007/s00381-020-04992-x -
Cephalalgia : An International Journal... Jan 2023A meta-analysis was conducted to analyze the incidence of typical and atypical headaches and outcomes following various treatments in patients with Chiari I malformation. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
A meta-analysis was conducted to analyze the incidence of typical and atypical headaches and outcomes following various treatments in patients with Chiari I malformation.
BACKGROUND
Headache is the most common symptom of Chiari malformation, which can be divided into typical and atypical subgroups to facilitate management. Much controversy surrounds the etiology, prevalence and optimal therapeutic approach for both types of headaches.
METHOD
We identified relevant studies published before 30 July 2022, with an electronic search of numerous literature databases. The results of this study were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.
RESULT
A total of 1913 Chiari malformation type I CIM patients were identified, 78% of whom presented with headache, within this group cephalgia was typical in 48% and atypical in 29% of patients, and migraine was the most common type of atypical headache. The ratio of typical/atypical headaches with international classification of headache disorders diagnosis was 1.53, and without international classification of headache disorders diagnosis was 1.56, respectively. The pooled improvement rates of typical headaches following conservative treatment, extradural decompression and intradural decompression were 69%, 88%, and 92%, respectively. The corresponding improvement rates for atypical headaches were 70%, 57.47%, and 69%, respectively. The complication rate in extradural decompression group was significantly lower than in intradural decompression group (RR, 0.31; 95% CI: 0.06-1.59, I = 50%, = 0.14). Low reoperation rates were observed for refractory headaches in extradural decompression and intradural decompression groups (1%).
CONCLUSION
The International Classification of Headache Disorders can assist in screening atypical headaches. extradural decompression is preferred for typical headaches, while conservative therapy is optimal for atypical headaches. A definite correlation exists between atypical headaches and Chiari Malformation Type I patients with higher prevalence than in the general population. Importantly, decompression is effective in relieving headaches in this particular patient population.
Topics: Humans; Arnold-Chiari Malformation; Treatment Outcome; Prevalence; Decompression, Surgical; Headache; Headache Disorders; Retrospective Studies
PubMed: 36694433
DOI: 10.1177/03331024221131356 -
Neurosurgery Nov 2021Chiari Malformation Type I (CM-I) is defined as cerebellar tonsil displacement more than 5 mm below the foramen magnum. This displacement can alter cerebrospinal fluid...
BACKGROUND
Chiari Malformation Type I (CM-I) is defined as cerebellar tonsil displacement more than 5 mm below the foramen magnum. This displacement can alter cerebrospinal fluid flow at the cervicomedullary junction resulting in Valsalva-induced headaches and syringomyelia and compress the brainstem resulting in bulbar symptoms. However, little is known about cognitive and psychological changes in CM-I.
OBJECTIVE
To prospectively assess cognitive and psychological performance in CM-I and determine whether changes occur after surgical decompression.
METHODS
Blinded evaluators assessed symptomatic CM-I patients ages ≥18 with a battery of neuropsychological and psychological tests. Testing was conducted preoperatively and 6 to 18 mo postoperatively. Data were converted to Z-scores based on normative data, and t-tests were used to analyze pre-post changes.
RESULTS
A total of 26 patients were included, with 19 completing both pre- and post-op cognitive assessments. All patients had resolution of Valsalva-induced headaches and there was improvement in swallowing dysfunction (P < .0001), ataxia (P = .008), and sleep apnea (P = .021). Baseline performances in visual perception and construction (z = -1.11, P = .001) and visuospatial memory (z = -0.93, P = .002) were below average. Pre-post comparisons showed that CM-I patients had stable cognitive and psychological functioning after surgery, without significant changes from preoperative levels.
CONCLUSION
CM-I patients had below average performance in visuospatial and visuoconstructional abilities preoperatively. Prospective longitudinal data following surgery demonstrated improved neurologic status without any decline in cognition or psychological functioning. Routine pre- and postoperative formal neuropsychological assessment in CM-I patients help quantify cognitive and behavioral changes associated with surgical decompression.
Topics: Arnold-Chiari Malformation; Cognition; Decompression, Surgical; Foramen Magnum; Humans; Magnetic Resonance Imaging; Prospective Studies; Syringomyelia; Treatment Outcome
PubMed: 34662899
DOI: 10.1093/neuros/nyab353 -
Journal of Neurology, Neurosurgery, and... Jul 2000The Arnold-Chiari malfomation is typically associated with downbeat nystagmus. Eye movement recordings in two patients with Arnold-Chiari malfomation type 1 showed, in...
The Arnold-Chiari malfomation is typically associated with downbeat nystagmus. Eye movement recordings in two patients with Arnold-Chiari malfomation type 1 showed, in addition to downbeat and gaze evoked nystagmus, intermittent nystagmus of skew. To date this finding has not been reported in association with Arnold-Chiari malfomation. Nystagmus of skew should raise the suspicion of Arnold-Chiari malfomation and prompt sagittal head MRI examination.
Topics: Adult; Arnold-Chiari Malformation; Arthroplasty, Replacement, Hip; Cerebellum; Electronystagmography; Female; Humans; Magnetic Resonance Imaging; Middle Aged; Nystagmus, Pathologic; Postoperative Complications
PubMed: 10864619
DOI: 10.1136/jnnp.69.1.124 -
The Journal of Veterinary Medical... May 2023A 2-day-old male black calf presented with neurological symptoms, including opisthotonus. It was unable to stand due to hindquarter paresis. At 5 days old, the calf was...
A 2-day-old male black calf presented with neurological symptoms, including opisthotonus. It was unable to stand due to hindquarter paresis. At 5 days old, the calf was able to stand, but exhibited a crossed forelimb gait. Computed tomography and magnetic resonance imaging revealed the expansion of the sutures between the squamous-lateral part of the occipital bone and between the occipital-temporal bone, cerebellar tonsillar herniation, posterior displacement of the brainstem, and cervical syringomyelia at 12 days old. This is the first case report of a live calf diagnosed with Arnold Chiari malformation classified as Chiari type 1.5 malformation in humans.
Topics: Animals; Cattle; Humans; Male; Arnold-Chiari Malformation; Cattle Diseases; Magnetic Resonance Imaging; Syringomyelia; Temporal Bone; Tomography, X-Ray Computed
PubMed: 37019664
DOI: 10.1292/jvms.22-0463 -
Neurologia Medico-chirurgica Sep 2022We investigated the mechanism underlying Chiari malformation type I (CM-I) and classified it according to the morphometric analyses of posterior cranial fossa (PCF) and...
We investigated the mechanism underlying Chiari malformation type I (CM-I) and classified it according to the morphometric analyses of posterior cranial fossa (PCF) and craniocervical junction (CCJ). Three independent subtypes of CM-I were confirmed (CM-I types A, B, and C) for 484 cases and 150 normal volunteers by multiple analyses. CM-I type A had normal volume of PCF (VPCF) and occipital bone size. Type B had normal VPCF and small volume of the area surrounding the foramen magnum (VAFM) and occipital bone size. Type C had small VPCF, VAFM, and occipital bone size. Morphometric analyses during craniocervical traction test demonstrated instability of CCJ. Foramen magnum decompression (FMD) was performed in 302 cases. Expansive suboccipital cranioplasty (ESCP) was performed in 102 cases. Craniocervical posterolateral fixation (CCF) was performed for CCJ instability in 70 cases. Both ESCP and FMD showed a high improvement rate of neurological symptoms and signs (84.4%) and a high recovery rate of the Japanese Orthopaedic Association (JOA) score (58.5%). CCF also showed a high recovery rate of the JOA score (69.7%), with successful joint stabilization (84.3%). CM-I type A was associated with other mechanisms that caused ptosis of the brainstem and cerebellum (CCJ instability and traction and pressure dissociation between the intracranial cavity and spinal canal cavity), whereas CM-I types B and C demonstrated underdevelopment of the occipital bone. For CM-I types B and C, PCF decompression should be performed, whereas for small VPCF, ESCP should be performed. CCF for CCJ instability (including CM-I type A) was safe and effective.
Topics: Arnold-Chiari Malformation; Cranial Fossa, Posterior; Decompression, Surgical; Humans; Magnetic Resonance Imaging
PubMed: 36031349
DOI: 10.2176/jns-nmc.2022-0078 -
Neurosurgery May 2019Epidemiology can assess the effect of Chiari I malformation (CM1) on the neurological health of a population and evaluate factors influencing CM1 development.
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.
Topics: Adult; Arnold-Chiari Malformation; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Prevalence; Russia; Tatarstan
PubMed: 29788393
DOI: 10.1093/neuros/nyy175