The newer classifications of the chiari malformations with clarifications: An anatomical review

Haddad, Fatima Azahraa; Qaisi, Ibraheem; Joudeh, Nagham; Dajani, Hamada; Jumah, Fareed; Elmashala, Amjad; Adeeb, Nimer; Chern, Joshua J.; Tubbs, R. Shane

doi:10.1002/ca.23051

Cited by 50 publications

(22 citation statements)

References 34 publications

(66 reference statements)

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“…However, like the canine disease, this description is problematic especially as there can be symptomatic disease and SM with smaller herniation (termed Chiari type 0). In an attempt to categorize the variations in humans there are now seven recognized types: 0, 1, 1.5, 2, 3, 3.5, and 4 ( 3 – 6 ). However, the distinction between types is challenging especially when the etiology is multifactorial and increasingly there is a call in human medicine that cerebellar tonsil herniation/Chiari malformation should be considered a radiographic sign and the focus of the diagnostic investigation should be to determine the cause of that herniation for example shallow posterior fossa ( 7 ), craniosynostosis ( 8 ), inherited disorders of connective tissue ( 9 ), spinal cord tethering ( 10 ), intracranial hypertension ( 11 ), or intracranial hypotension ( 12 ).…”

Section: Introductionmentioning

confidence: 99%

Clinical Application of Diagnostic Imaging of Chiari-Like Malformation and Syringomyelia

2018

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Chiari-like malformation (CM) and syringomyelia (SM) is a frequent diagnosis in predisposed brachycephalic toy breeds since increased availability of MRI. However, the relevance of that MRI diagnosis has been questioned as CM, defined as identification of a cerebellar herniation, is ubiquitous in some breeds and SM can be asymptomatic. This article reviews the current knowledge of neuroanatomical changes in symptomatic CM and SM and diagnostic imaging modalities used for the clinical diagnosis of CM-pain or myelopathy related to SM. Although often compared to Chiari type I malformation in humans, canine CM-pain and SM is more comparable to complex craniosynostosis syndromes (i.e., premature fusion of multiple skull sutures) characterized by a short skull (cranial) base, rostrotentorial crowding with rostral forebrain flattening, small, and ventrally orientated olfactory bulbs, displacement of the neural tissue to give increased height of the cranium and further reduction of the functional caudotentorial space with hindbrain herniation. MRI may further reveal changes suggesting raised intracranial pressure such as loss of sulci definition in conjunction with ventriculomegaly. In addition to these brachycephalic changes, dogs with SM are more likely to have craniocervical junction abnormalities including rostral displacement of the axis and atlas with increased odontoid angulation causing craniospinal junction deformation and medulla oblongata elevation. Symptomatic SM is diagnosed on the basis of signs of myelopathy and presence of a large syrinx that is consistent with the neuro-localization. The imaging protocol should establish the longitudinal and transverse extent of the spinal cord involvement by the syrinx. Phantom scratching and cervicotorticollis are associated with large mid-cervical syringes that extend to the superficial dorsal horn. If the cause of CSF channel disruption and syringomyelia is not revealed by anatomical MRI then other imaging modalities may be appropriate with radiography or CT for any associated vertebral abnormalities.

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Section: Introductionmentioning

confidence: 99%

Clinical Application of Diagnostic Imaging of Chiari-Like Malformation and Syringomyelia

2018

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“…Headache is the most common presenting feature. It is classically described as a sub-occipital headache or neck pain triggered or exacerbated by Valsalva-like maneuvers (such as coughing or straining) [6][7].…”

Section: Discussionmentioning

confidence: 99%

Semilobar Holoprosencephaly: Capacious Anomaly in the Cephalad

Veluchamy¹,

Murugan²

2020

Cureus

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The holoprosencephalies (HPEs) are a group of disorders that are characterized by a failure of differentiation and midline cleavage of the prosencephalon, which usually occurs between days 18 and 28 of gestation. HPE has been divided into three subcategories based on the structural malformation: alobar, semilobar, and lobar HPE. Middle interhemispheric variant (MIH) or syntelencephaly is also considered as a milder variant of HPE. It is estimated to occur in 1/16,000 live births and 1/250 conceptuses. HPE is caused by genetic factors or environmental factors and teratogens. Clinical presentation depends on the severity of the malformation. Severe cases are usually associated with facial abnormalities like hypertelorism or midline facial clefts. HPE is diagnosed prenatally by ultrasound and MRI. Treatment of HPE is supportive and symptomatic. The clinical outcome depends on the severity of HPE and associated medical and neurological complications.

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“…8 An advanced form of CM-1, associated with caudal migration of the obex beyond the foramen magnum, and elongation of the medulla and fourth ventricle, is described as CM-1.5 (Fig 2). 3,4,9 Tubbs et al 10 described a prevalence of CM-1.5 in 17% of individuals initially diagnosed as CM-1. 9 The higher rates of revision surgery for persistent syringohydromyelia after posterior fossa decompression in CM-1.5 highlight the need to distinguish between the 2 variants.…”

Section: Types and Prevalence Of Cmsmentioning

confidence: 99%

“…1,2 Since the initial description of CM-3, there have only been approximately 60 reported cases. 3,14 The only reported case of occipitocervical encephalocele communicating with the foregut has been referred to as CM-3.5. 3,15,16 CM-4, currently termed "primary cerebellar agenesis" or "severe cerebellar hypoplasia," was initially described as cerebellar hypoplasia with occipital encephalocele.…”

Section: Types and Prevalence Of Cmsmentioning

confidence: 99%

“…3,14 The only reported case of occipitocervical encephalocele communicating with the foregut has been referred to as CM-3.5. 3,15,16 CM-4, currently termed "primary cerebellar agenesis" or "severe cerebellar hypoplasia," was initially described as cerebellar hypoplasia with occipital encephalocele. 2,3 CM 5 is the coexistence of lumbar meningocele and/or myelomeningocele (CM-2), with a low occipital or high cervical myelomeningocele (CM-3).…”

Section: Types and Prevalence Of Cmsmentioning

confidence: 99%

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

Hiremath

Fitsiori²,

Boto³

et al. 2020

AJNR Am J Neuroradiol

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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. ABBREVIATION: CM ¼ Chiari malformation C hiari malformations (CMs) are a group of rhombencephalic abnormalities, initially described by Hans Chiari, traditionally classified into 4 types. 1-3 Types I to III are associated with a varying degree of caudal displacement of the contents of the posterior fossa, along with cerebellar tonsillar herniation through the foramen magnum. Type IV is characterized by cerebellar hypoplasia or aplasia and an occipital encephalocele. 1-3 Because of the complex nature of the associated abnormalities, CMs can present with diverse clinical manifestations, secondary to the involvement of the cerebellum, brain stem, spinal cord, lower cranial nerves, and altered CSF flow dynamics. Recent advances in imaging techniques, such as phase-contrast imaging, cine MR imaging, and DTI, with frequent imaging and surgical management of these

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The newer classifications of the chiari malformations with clarifications: An anatomical review

Cited by 50 publications

References 34 publications

Clinical Application of Diagnostic Imaging of Chiari-Like Malformation and Syringomyelia

Clinical Application of Diagnostic Imaging of Chiari-Like Malformation and Syringomyelia

Semilobar Holoprosencephaly: Capacious Anomaly in the Cephalad

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

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