Pathogenesis of Chiari Malformation: A Morphometric Study of the Posterior Cranial Fossa

Object The chronic tonsillar herniation defining Chiari malformation Type I (CMI) is thought to result from overcrowding of a normally developing hindbrain within a congenitally small posterior cranial fossa (PCF) due to occipital hypoplasia. The goals in the present study were to authenticate the cranioencephalic disproportion in a group of patients with CMI and to discuss new developmental aspects according to which part of the occipital bone was underdeveloped. Methods The authors retrospectively examined a group of 17 patients with CMI. Measurements of osteotentorial and neural structures of the PCF were made on MR images of the brain. The results were compared with findings in 30 healthy controls by using the Mann-Whitney U-test. Results Dimensions of the neural structures did not differ between the 2 groups of patients. The mean length of the basiocciput was significantly shorter in the CMI group (19.4 mm) compared with the control group (25.7 mm; p = 0.0003). The mean diameter of the foramen magnum was larger in the CMI group, but this difference was not statistically significant. The dimensions of the supraocciput and the mean angle of the cerebellar tentorium were identical in the 2 groups. Conclusions Data in this study support the idea that occipital hypoplasia is the main cause of overcrowding within the PCF. Basioccipital shortness is a cardinal feature of the resultant shallow PCF and could proceed from a congenital disorder of the cephalic mesoderm of the parachordal plate or occur later in the infancy because of premature stenosis of the sphenooccipital synchondrosis.

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A Computational Study of Unsteady Resistance to Cerebrospinal Fluid Flow in Type I Chiari Malformation

ASME 2010 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2010-19642 ◽

2010 ◽

Author(s):

Nicholas Shaffer ◽

George Poppe ◽

Francis Loth ◽

Oliver Wieben ◽

Victor Haughton ◽

...

Keyword(s):

Symptom Severity ◽

Chiari Malformation ◽

Diagnostic Method ◽

Computational Study ◽

Posterior Cranial Fossa ◽

Type I ◽

Cerebrospinal Fluid Flow ◽

Complex Disorder ◽

Hindbrain Herniation ◽

Cranial Fossa

Type I Chiari malformation (CM) is a complex disorder of the craniospinal system characterized by underdevelopment of the posterior cranial fossa and overcrowding of the normally developed hindbrain [1], and may be a precursor to more severe secondary disorders such as syringomyelia and hydrocephalus. Diagnosis of CM has proven to be difficult and may often take years to properly identify, as associated neurological symptoms may vary widely and overlap with symptoms of other disorders. Current methods of quantifying the severity of CM, such as radiographical measurement of the depth of hindbrain herniation into the spinal canal or measurement of posterior cranial fossa volume do not necessarily correlate to the symptom severity. Hence, there exists a need for a quantitative diagnostic method which may better characterize the severity of CM and, potentially, help neurosurgeons determine candidates for surgical treatment.

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MRI-based Morphometric Analysis of Posterior Cranial Fossa in the Diagnosis of Chiari Malformation Type I

Journal of Neuroimaging ◽

10.1111/jon.12007 ◽

2013 ◽

Vol 24 (3) ◽

pp. 250-256 ◽

Cited By ~ 37

Author(s):

Aintzane Urbizu ◽

Maria-Antonia Poca ◽

Xavier Vidal ◽

Alex Rovira ◽

Juan Sahuquillo ◽

...

Keyword(s):

Morphometric Analysis ◽

Chiari Malformation ◽

Posterior Cranial Fossa ◽

Type I ◽

Chiari Malformation Type I ◽

Cranial Fossa

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Volumetric analysis of the posterior cranial fossa in a family with four generations of the Chiari malformation Type I

Journal of Neurosurgery Pediatrics ◽

10.3171/ped-08/01/021 ◽

2008 ◽

Vol 1 (1) ◽

pp. 21-24 ◽

Cited By ~ 39

Author(s):

R. Shane Tubbs ◽

Mark Hill ◽

Marios Loukas ◽

Mohammadali M. Shoja ◽

W. Jerry Oakes

Keyword(s):

Posterior Fossa ◽

Chiari Malformation ◽

Familial Aggregation ◽

Volumetric Analysis ◽

Posterior Cranial Fossa ◽

Preoperative Imaging ◽

Type I ◽

Chiari Malformation Type I ◽

Hindbrain Herniation ◽

Cranial Fossa

Object Many authors have concluded that the Chiari malformation Type I (CM-I) is due to a smaller than normal posterior cranial fossa. In order to establish this smaller geometry as the cause of hindbrain herniation in a family, the authors of this paper performed volumetric analysis in a family found to have this malformation documented in 4 generations. Methods Members from this family found to have a CM-I by imaging underwent volumetric analysis of their posterior cranial fossa using the Cavalieri method. Results No member of this family found to have CM-I on preoperative imaging had a posterior fossa that was significantly smaller than that of age-matched controls. Conclusions The results of this study demonstrate that not all patients with a CM-I will have a reduced posterior cranial fossa volume. Although the mechanism for the development of hindbrain herniation in this cohort is unknown, this manifestation can be seen in multiple generations of a familial aggregation with normal posterior fossa capacity.

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Pathogenesis of Chiari malformation: a morphometric study of the posterior cranial fossa

Journal of Neurosurgery ◽

10.3171/jns.1997.86.1.0040 ◽

1997 ◽

Vol 86 (1) ◽

pp. 40-47 ◽

Cited By ~ 367

Author(s):

Misao Nishikawa ◽

Hiroaki Sakamoto ◽

Akira Hakuba ◽

Naruhiko Nakanishi ◽

Yuichi Inoue

Keyword(s):

Posterior Fossa ◽

Medulla Oblongata ◽

Chiari Malformation ◽

Volume Ratio ◽

Basilar Invagination ◽

Posterior Cranial Fossa ◽

Control Group ◽

Adult Type ◽

Content Type ◽

Cranial Fossa

✓ To investigate overcrowding in the posterior cranial fossa as the pathogenesis of adult-type Chiari malformation, the authors studied the morphology of the brainstem and cerebellum within the posterior cranial fossa (neural structures consisting of the midbrain, pons, cerebellum, and medulla oblongata) as well as the base of the skull while taking into consideration their embryological development. Thirty patients with Chiari malformation and 50 normal control subjects were prospectively studied using neuroimaging. To estimate overcrowding, the authors used a “volume ratio” in which volume of the posterior fossa brain (consisting of the midbrain, pons, cerebellum, and medulla oblongata within the posterior cranial fossa) was placed in a ratio with the volume of the posterior fossa cranium encircled by bony and tentorial structures. Compared to the control group, in the Chiari group there was a significantly larger volume ratio, the two occipital enchondral parts (the exocciput and supraocciput) were significantly smaller, and the tentorium was pronouncedly steeper. There was no significant difference in the posterior fossa brain volume or in the axial lengths of the hindbrain (the brainstem and cerebellum). In six patients with basilar invagination the medulla oblongata was herniated, all three occipital enchondral parts (the basiocciput, exocciput, and supraocciput) were significantly smaller than in the control group, and the volume ratio was significantly larger than that in the Chiari group without basilar invagination. These results suggest that in adult-type Chiari malformation an underdeveloped occipital bone, possibly due to underdevelopment of the occipital somite originating from the paraxial mesoderm, induces overcrowding in the posterior cranial fossa, which contains the normally developed hindbrain. Basilar invagination is associated with a more severe downward herniation of the hindbrain due to the more severely underdeveloped occipital enchondrium, which further exacerbates overcrowding of the posterior cranial fossa.

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Imaging-Based Features of Headaches in Chiari Malformation Type I

Neurosurgery ◽

10.1227/neu.0000000000000740 ◽

2015 ◽

Vol 77 (1) ◽

pp. 96-103 ◽

Cited By ~ 15

Author(s):

Noam Alperin ◽

James R. Loftus ◽

Carlos J. Oliu ◽

Ahmet M. Bagci ◽

Sang H. Lee ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Chiari Malformation ◽

Posterior Cranial Fossa ◽

Type I ◽

Intracranial Volume ◽

Resonance Imaging ◽

Chiari Malformation Type I ◽

Intracranial Compliance ◽

Cranial Fossa

Abstract BACKGROUND: Suboccipital cough-induced headaches are considered a hallmark symptom of Chiari malformation type I (CMI). However, non--Valsalva-related suboccipital headaches and headaches in other locations are also common in CMI. The diagnostic significance and the underlying factors associated with these different headaches types are not well understood. OBJECTIVE: To compare cranial morphology and hydrodynamics in 3 types of headaches in CMI to better understand the pathophysiological basis for the different headache characteristics. METHODS: Twenty-two cranial physiological and morphological measures were obtained with specialized magnetic resonance imaging scans from 63 symptomatic pretreated CMI patients, 40 with suboccipital headaches induced by Valsalva maneuvers (34 women; age, 36 ± 10 years), 15 with non--Valsalva-related suboccipital headaches (10 women; age, 33 ± 9 years), 8 with nonsuboccipital non--Valsalva-induced headaches (8 women; age, 39 ± 13 years), and 37 control subjects (24 women; age, 36 ± 12 years). Group differences were identified with the use of the 2-tailed Student t test. RESULTS: Posterior cranial fossa markers of CMI were similar among the 3 headache subtypes. However, the Valsalva-related suboccipital headaches cohort demonstrated a significantly lower intracranial compliance index than the non--Valsalva-related suboccipital headaches cohort (7.5 ± 3.4 vs 10.9 ± 4.9), lower intracranial volume change during the cardiac cycle (0.48 ± 0.19 vs 0.61 ± 0.16 mL), and higher magnetic resonance imaging--derived intracranial pressure (11.1 ± 4.3 vs 7.7 ± 2.8 mm Hg; P = .02). The Valsalva-related suboccipital headaches cohort had smaller intracranial and lateral ventricular volumes compared with the healthy cohort. The non--Valsalva-related suboccipital headaches cohort had reduced venous drainage through the jugular veins. CONCLUSION: Valsalva-induced worsening of occipital headaches appears to be related to a small intracranial volume rather than the smaller posterior cranial fossa. This explains the reduced intracranial compliance and corresponding higher pressure measured in CMI patients with headaches affected by Valsalva maneuvers.

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Classification of Chiari Malformations Based on the Mechanism of Ptosis of the Brain Stem and Cerebellum—Morphometric Study of the Posterior Cranial Fossa—

Spinal Surgery ◽

10.2531/spinalsurg.33.63 ◽

2019 ◽

Vol 33 (1) ◽

pp. 63-68

Author(s):

Misao Nishikawa ◽

Hiroki Ohata ◽

Thomas H. Milhorat ◽

Paolo A. Bolognese ◽

Roger W. Kula ◽

...

Keyword(s):

Brain Stem ◽

Posterior Cranial Fossa ◽

Morphometric Study ◽

Cranial Fossa ◽

The Brain ◽

Chiari Malformations

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MRT peculiarities of posterior cranial fossa in family syringomyelia

Neurology Bulletin ◽

10.17816/nb89666 ◽

2003 ◽

Vol XXXV (1-2) ◽

pp. 44-46

Author(s):

A. V. Selezneva ◽

E. G. Mendelevich ◽

I. M. Mikhailov ◽

L. R. Valieva ◽

E. I. Bogdanov

Keyword(s):

Chiari Malformation ◽

Posterior Cranial Fossa ◽

Healthy People ◽

Cerebellar Tonsil ◽

Type I ◽

Chiari Malformation Type I ◽

Cranial Fossa

It was found that syringomyelic patients and clinically healthy people out of the families with MRT-features of Chiari malformation, type I, had a confident decrease of depth and square of posterior cranial fossa. Relatives of patients, having no signs of Chiari malformation, type I, had the same changes as well. There was made a conclusion about presence of posterior cranial fossa hypoplasia in all patients with hereditary syryngomyelia and in members of their families, both having MRT-features of Chiari malformation type I, and having no malformation. It was supposed that posterior cranial fossa hypoplasia is a neurovisual reflection of its hereditary phonotype, and the latter in some cases leads to cerebellar tonsil ptosis, and if there are some endogenic and exogenic factors to development of family syringomyelia.

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Cephalometric oropharynx and oral cavity analysis in Chiari malformation Type I: a retrospective case-control study

Journal of Neurosurgery ◽

10.3171/2016.1.jns151590 ◽

2017 ◽

Vol 126 (2) ◽

pp. 626-633 ◽

Cited By ~ 9

Author(s):

Aintzane Urbizu ◽

Alex Ferré ◽

Maria-Antonia Poca ◽

Alex Rovira ◽

Juan Sahuquillo ◽

...

Keyword(s):

Oral Cavity ◽

Sleep Disorders ◽

Chiari Malformation ◽

Case Control ◽

Posterior Cranial Fossa ◽

Sensory Loss ◽

Type I ◽

Retrospective Case ◽

Chiari Malformation Type I ◽

Cranial Fossa

OBJECTIVETraditionally, Chiari malformation Type I has been related to downward herniation of the cerebellar tonsils as a consequence of an underdeveloped posterior cranial fossa. Although the common symptoms of Chiari malformation Type I are occipital headaches, cervical pain, dizziness, paresthesia, and sensory loss, patients often report symptoms related to pharyngeal dysfunction such as choking, regurgitation, dysphagia, aspiration, chronic cough, and sleep disorders. In addition, tracheal intubation is often difficult in these patients. The purpose of this study was to analyze the morphological features of the oropharynx and oral cavity in patients with Chiari malformation Type I to help identify underlying anatomical anomalies leading to these debilitating symptoms.METHODSSeventy-six adult patients with symptomatic Chiari malformation Type I with cerebellar tonsillar descent greater than 5 mm below the foramen magnum and a small posterior cranial fossa and 49 sex-matched controls were selected to perform a retrospective case-control MRI-based morphometric study in a tertiary hospital. Eleven linear and areal parameters of the oropharyngeal cavity on midsagittal T1-weighted MRI were measured and the average values between patients and control cohorts were compared. Correlations between variables showing or approaching statistical significance in these structures and posterior cranial fossa measurements related with the occipital bone were sought.RESULTSSignificant differences were detected for several oropharynx and oral cavity measures in the patient cohort, primarily involving the length and thickness of the soft palate (p = 9.5E-05 and p = 3.0E-03, respectively). A statistically significant (p < 0.01) moderate correlation between some of these variables and posterior cranial fossa parameters was observed.CONCLUSIONSThe existence of structural oropharyngeal and oral cavity anomalies in patients with Chiari malformation Type I was confirmed, which may contribute to the frequent occurrence of respiratory and deglutitory complications and sleep disorders in this syndrome.

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