Prevalence of Chiari type I malformation on cervical magnetic resonance imaging: a retrospective study

Abstract

Chiari malformation, also known as Arnold-Chiari malformation, is characterized by the caudal herniation of posterior fossa structures through the foramen magnum into the cervical spinal canal. It is a congenital malformation of the craniovertebral junction and hindbrain often associated with other abnormalities of the cerebrospinal axis. [1][2][3][4][5][6][7][8] Chiari malformation is classically classified into four types. Chiari type I is the caudal herniation of cerebellar tonsils through foramen magnum by no more than 3 or 5 mm. [1,3,4,6,7,[9][10][11] In Chiari type II, there is a caudal herniation of the brainstem and the fourth ventricle into upper cervical canal through foramen magnum, frequently associated with myelomeningocele, and rarely associated with spina bifida occulta. Chiari type III is the most severe form in which posterior fossa structures herniate into an occipitocervical meningocele sac. Severe cerebellar hypoplasia in absence of cerebellar herniation is observed in Chiari type AbstractObjectives: Chiari malformation is characterized by caudal herniation of cerebellar tonsils from foramen magnum into the cervical canal on radiological images. Type I Chiari malformation is the herniation of cerebellar tonsils more than 3 mm which does not cause any symptoms until adulthood. In this study, we aimed to investigate the prevalence of Chiari type I malformation. Methods:In this retrospective study, cervical magnetic resonance images taken between 2013 and 2015 were retrospectively analyzed. The patients were 18-70 year old males and females. Type I Chiari malformation was defined as an inferior displacement of the cerebellar tonsils more than 3 mm below the opisthion-basion line. The patients with intracranial lesions, hydrocephalus or previous craniotomy were excluded from the study. Results:The prevalence of Chiari type I malformation was found as 4% when both genders were taken into consideration. The prevalence was 3.3% in females and 0.7% in males. Chiari type I malformation was associated with syringomyelia in 0.5% of females and 0.2% of males. In the present study, concomitant syringomyelia was observed in 0.7% of the patients. On the other hand, incidence of Chiari type I malformation was found relatively higher in the patients with scoliosis (15.4%). The ratio of this co-occurrence was higher in females (11.4%) when compared to the males (4%). Conclusion:In the present study, the prevalence of Chiari type I malformation was investigated in a large population, consisting of 2480 individuals, and its association with syringomyelia and scoliosis.

Signs of Intracranial Hypertension, Hypermobility, and Craniocervical Obstructions in Patients With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

“…That criteria was fulfilled by 3.4% of our participants as compared to prevalence in a normal population, which is estimated to be 0.3–1%, indicating at least a three-fold higher prevalence in our participants with ME/CFS ( 12 ). Others have used a definition for Chiari 1 malformation when the position of the tonsils are > 3 mm below the McRae line, which occurred in 4% of patients referred for MRI for different diagnosis in a retrospective study of 2,480 MRI scans ( 19 ). Normal values vary with age and sex, and the position of the cerebellar tonsils rises with age due to general cerebral atrophy ( 12 ).…”

Bragee Bertilson et al. - ME CFS and Intracranial Hypertension now published please redirect to Frontiers

“…That criteria was fulfilled by 3.4% of our participants as compared to prevalence in a normal population, which is estimated to be 0.3-1%, indicating at least a threefold higher prevalence in our participants with ME/CFS (12). Others have used a definition for Chiari 1 malformation when the position of the tonsils are >3 mm below the McRae line, which occurred in 4% of patients referred for MRI for different diagnosis in a retrospective study of 2,480 MRI scans (19). Normal values vary with age and sex, and the position of the cerebellar tonsils rises with age due to general cerebral atrophy (12).…”

Dural Closure in Chiari I Malformation. Technique Description and Analysis of Results

“…The low availability and high cost of heterologous grafts or dural substitutes makes the reconstruction after posterior fossa decompression a procedure with potential harmful complications related to CSF fistula and its consequences [18][19][20][21][22][23] . A low cost, safe and efficient method for dural closure is a valuable alternative to address these complications [18][19][20][21][22][23] .…”