conclusion our results concerning cranium morphometry support the theory that hypoplastic posterior cranial fossa due to mesodermal insufficiency may play a role in the etiology of tonsillar herniation. results in individuals with tonsillar herniation, while the front-back diameter of the foramen magnum, the cerebellum height, and the sagittal diameter of the cerebellum increased, the maximum c...

abstract meningeal melanocytoma is a primary melanocytic neoplasm with certain mr and immunohistochemical characteristics worthy to note. in a 38-year-old man with a complaint of headache for a couple of years and recently added nausea, vomiting, diplopia, progressive visual blurring and hearing loss, magnetic resonance imaging (mri) was remarkable for t1 shortening of leptomeninges and certain...

Downward displacement of cerebellar tonsils more than 5 mm below the foramen magnum is named as Chiari type I malformation and named benign tonsillar ectopia if herniation is less than 3 mm. It does not just depend on congenital causes. There are also some reasons for acquired Chiari Type 1 and benign tonsillar ectopia/herniation. Trauma is one of them. Trauma may increase tonsillar ectopia or ...

OBJECT Indications for duraplasty in treatment of Chiari malformation Type I (CM-I) remain unclear. In the present study, the authors evaluate their surgical experience to determine whether intraoperative ultrasonography is effective in the selection of patients with CM-I who can be adequately treated with craniectomy alone without duraplasty. METHODS The authors reviewed the records of 256 c...

BACKGROUND AND PURPOSE The cause of syringomyelia in patients with Chiari I remains uncertain. Cervical spine anatomy modifies CSF velocities, flow patterns, and pressure gradients, which may affect the spinal cord. We tested the hypothesis that cervical spinal anatomy differs between Chiari I patients with and without syringomyelia. MATERIALS AND METHODS We identified consecutive patients wi...

OBJECTIVE In this study, we aimed to investigate the underlying ethiological factors in chiari malformation (CM) type-I (CMI) via performing volumetric and morphometric length-angle measurements. METHODS A total of 66 individuals [33 patients (20-65 years) with CMI and 33 control subjects] were included in this study. In sagittal MR images, tonsillar herniation length and concurrent anomalies...

BACKGROUND Cervical spinal canal tapering may increase CSF velocities and pressures. One report suggests that the cervical spinal canal tapers more steeply in patients with Chiari I than in healthy subjects. The goal of this study was to test the conclusion by measuring spinal canal tapering in another cohort of patients. MATERIALS AND METHODS Consecutive patients with scoliosis and MR imagin...

Smaller posterior fossa (PF) volume has been suggested to be one of the mechanisms responsible for tonsillar herniation through the foramen magnum in patients with Chiari I malformation (CM I). Although previous radiological analyses of the cranial anatomy have suggested a smaller PF volume in patients with CM I, the relationship of the PF volume to decompressive surgery has not been reported. ...

A 19-year-old woman presented with a five month history of headaches. Initially the headaches had been intermittent. For the two months prior to presentation the patient had a constant headache. There was no precipitant at onset. The headache was improved by recumbancy. It was associated with daily vomiting resulting in a 20 pound weight loss but no photophobia or phonophobia. The neurological ...

We present a 41-year-old man with Chiari type 1 malformation and cervical syringomyelia. Although the tonsillar herniation persisted, his syringomyelia was almost completely resolved during an eleven-year time period without surgery.