MR imaging of Chiari II malformation

Gammal, T el; Mark, EK; Brooks, B S

doi:10.2214/ajr.150.1.163

Cited by 50 publications

(19 citation statements)

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“…Although the pathways appeared to be anatomically pa tent, it was concluded that the aqueduct could at least be physiologically atretic or stenosed. Like the computed tomography scan, the magnetic resonance visualization of the aqueduct has been inconstant [24], In a series of 24 patients with Chiari malformation ranging in age from 1 to 20 years, Wolpert et al [25] noted the nonvisualization of the aqueduct in 17 of 24 patients. However, in many of these patients, the lack of aqueductal patency may have been a secondary phenomenon to shunting.…”

Section: Discussionmentioning

confidence: 99%

Contemporaneous Shunting with Repair of Myelomeningocele

Parent

McMillan²

1995

Pediatr Neurosurg

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The combination of overt hydrocephalus and an open myelomeningocele in a newborn has prompted some authors to advocate the repair of the myelomeningocele and the performance of a shunt procedure during the same anesthetic procedure. Advocates of this approach stress the merits of administering only one anesthetic, diminution in incidence of cerebrospinal fluid leaks from the repair, and shortened hospital stay and the resultant cost-effectiveness. This study was performed to assess the complication rate of shunts inserted at the time of myelomeningocele repair as well as of those inserted at a later date as a separate procedure. It would later appear that the insertion of a ventriculoperitoneal shunt, contemporaneous with the repair of the myelomeningocele, does not increase the risks of shunt infection or shunt malfunction within the 1st year of life.

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Section: Discussionmentioning

confidence: 99%

Contemporaneous Shunting with Repair of Myelomeningocele

Parent

McMillan²

1995

Pediatr Neurosurg

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“…None of the 4 patients treated in utero had significant cerebellar herniation, while the vast majority of an unselected group treated conventionally did. These findings are supported by both a necropsy series [7] and by larger series of patients with Chiari II studied with MRI [8][9][10]. In those studies more than 95% of patients with myelomeningocele had cerebellar and/or brainstem elements extending below the foramen magnum.…”

Section: Discussionmentioning

confidence: 65%

Reduced Hindbrain Herniation after Intrauterine Myelomeningocele Repair: A Report of Four Cases

Tulipan¹,

1998

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Background: It has been theorized that fetal myelomeningocele repair may reduce ongoing intrauterine injury and perhaps allow healing and regeneration of dysplastic neural tissue. We report on the postnatal imaging studies of the first 4 patients to have undergone intrauterine myelomeningocele repair at our institution. Methods: Each of the 4 patients underwent postnatal sonographic and MRI. In addition, the postnatal ultrasounds of these 4 were compared to a group of retrospective controls. Results: MRI scans of the 4 experimental subjects revealed no evidence of hindbrain herniation while other stigmata of the Chiari-II malformation persisted. In comparison to the retrospective controls this absence of herniation was distinctly unusual. Conclusion: Intrauterine myelomeningocele repair may reduce the degree of hindbrain herniation normally seen in patients with myelomeningocele. This raises the possibility that intrauterine repair may decrease the morbidity associated with the Chiari type-II malformation including brainstem dysfunction, hydrocephalus and syringomyelia.

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“…The degree of downward displacement of the cerebellum depends on the length and elasticity of the attached inferior medullary velum [17]. Whereas in ACMII fetuses, the cerebellum is rarely seen herniating below the level of the foramen magnum [21, 22], in ACMII neonates, it mostly does [10, 23, 24]. It seems logical to assume that in those cases, the cerebellar herniation develops during the 3rd trimester of pregnancy.…”

Section: Discussionmentioning

confidence: 99%

The Arnold-Chiari Type II Malformation at Midgestation

Beuls

Vanormelingen²,

Aalst

et al. 2003

Pediatr Neurosurg

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The Arnold-Chiari malformation type II (ACMII) is reported to be reversible after closure of a myelomeningocele at midgestation. To elucidate the developmental state of the ACMII malformation at the approximate time fetal surgery is performed, the ACMII of a 20-week human fetus was investigated in vitro using high-field magnetic resonance microscopy at 9.4 T and compared with the hindbrain of a neurologically intact fetus of the same gestational age. Up to 20 weeks of gestation, the developmental failures caused by the early embryonic herniation of the posterior fossa contents are the dominant feature of fetal ACMII, but after 20 weeks, the accelerated and disproportionate growth of the cerebellum dominates. As midgestational surgery stops the leakage of cerebrospinal fluid, the posterior fossa will expand in time to allow further normal growth of both the cerebellum and brain stem. Some early developmental anomalies already present in the primitive rhombencephalon due to early embryonic hindbrain herniation as well as some intra-axial anomalies are probably not reversible.

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MR imaging of Chiari II malformation

Cited by 50 publications

References 1 publication

Contemporaneous Shunting with Repair of Myelomeningocele

Contemporaneous Shunting with Repair of Myelomeningocele

Reduced Hindbrain Herniation after Intrauterine Myelomeningocele Repair: A Report of Four Cases

The Arnold-Chiari Type II Malformation at Midgestation

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