The Small Posterior Cranial Fossa Syndrome and Chiari Malformation Type 0.

Patients showing typical Chiari malformation type 1 (CM1) signs and symptoms frequently undergo cranial and cervical MRI. In some patients, MRI documents >5 mm of cerebellar tonsillar herniation (TH) and the diagnosis of CM1. Patients with 3−5 mm TH have “borderline” CM1.

Posterior cranial fossa and cervical spine morphometric abnormalities in symptomatic Chiari type 0 and Chiari type 1 malformation patients with and without syringomyelia.

Background: To better understand how anatomical features of Chiari malformation type 0 (CM0) result in the manifestation of Chiari malformation type 1 (CM1) signs and symptoms, we conducted a morphometric study of the posterior cranial fossa (PCF) and cervical canal in patients with CM1 and CM0.

Methods: This retrospective study had a STROBE design and included 120 adult patients with MRI evidence of a small PCF (SPCF), typical clinical symptoms of CM1, and a diagnosis of CM1, CM0, or SPCF-TH0-only (SPCF with cerebellar ectopia less than 2 mm and without syringomyelia). Patients were divided by MRI findings into 4 groups: SPCF-TH0-only, SPCF-TH0-syr (CM0 with SPCF and syringomyelia), SPCF-CM1-only (SPCF with cerebellar ectopia 5 mm or more without syringomyelia), and SPCF-CM1-syr (CM1 with syringomyelia).

Epidemiology of Symptomatic Chiari Malformation in Tatarstan: Regional and Ethnic Differences in Prevalence.

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.