In some adult patients with cervical syringomyelia, MRI studies do not identify primary disease within the foramen magnum or spinal canal. To identify the etiology of this idiopathic type of syringomyelia, clinical features and posterior fossa (PF) measurements from 17 of these patients, 17 patients with Chiari I-type syringomyelia, and 32 control subjects were compared. Idiopathic syringomyelia and Chiari I-type syringomyelia manifested central cervical myelopathy and a small PF with narrow CSF spaces, suggesting that they develop by the same mechanism.

Medical article медицинская статья

OBJECTIVE AND IMPORTANCE: The natural history of syringomyelia is highly unpredictable, and some patients experience improvement or stabilization without surgery. However, the mechanisms of the formation and spontaneous resolution of syringomyelia remain controversial. This report concerns two patients with syringomyelia who demonstrated spontaneous reductions in syrinx size, accompanied by symptomatic improvement.CLINICAL PRESENTATION: One patient was a 10-year-old girl with syringomyelia associated with a tight cisterna magna and basilar impression, who demonstrated a spontaneous decrease in syrinx size, accompanied by symptomatic improvement, in 22 months. The other patient was a 39-year-old man with syringomyelia associated with a Chiari I malformation, who demonstrated a spontaneous reduction in syrinx size and neurological improvement, accompanied by elevation of the cerebellar tonsils, 6 months after diagnosis.INTERVENTION: The patients were monitored.CONCLUSION: The mechanisms of spontaneous resolution of syringomyelia, as well as the factors leading to the cerebrospinal fluid flow disturbances that cause syringomyelia, may vary. Resolution of foramen magnum lesion-related syringomyelia may be the result of spontaneous correction of the abnormal cerebrospinal fluid flow, as observed in our cases, or of cavity fluid drainage into the spinal arachnoid space because of spinal cord fissuring.

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. Typical symptoms of CM1 were found in 868 patients. Data from neurological examination and magnetic resonance imaging (MRI) measurement of posterior cranial fossa structures were analyzed. RESULTS: MRI evidence of CM1, defined as cerebellar tonsils lying at least 5 mm inferior to the foramen magnum, was found in 67% of symptomatic patients. Another 33% of symptomatic patients had 2 to 4 mm of tonsillar ectopia, which we defined as “borderline Chiari malformation type 1 (bCM1).” The period prevalence in the entire RT for symptomatic CM1 was 20:100 000; for bCM1 was 10:100 000; and for CM1 and bCM1 together was 30:100 000. Prevalence of patients with CM1 symptoms was greater in the northern than southern districts of Tatarstan, due to a high prevalence (413:100 000) of CM1 in the Baltasy region in one of the northern districts. CONCLUSION: One-third of patients with typical symptoms of CM1 had less than 5 mm of tonsillar ectopia (bCM1). Assessments of the health impact of CM1-type symptoms on a patient population should include the bCM1 patient group. A regional disease cluster of patients with Chiari malformation was found in Baltasy district of RT and needs further study.