Chiari Malformations
Chiari malformations designate a group of developmental disorders characterized by anatomical deformities of the posterior fossa. They are either evident at birth or even prenatally or become symptomatic during adolescence or adulthood. Diagnosis relies m
- PDF / 387,461 Bytes
- 14 Pages / 439.37 x 666.142 pts Page_size
- 48 Downloads / 211 Views
85
Mario Manto and Herweh Christian
Abstract
Chiari malformations designate a group of developmental disorders characterized by anatomical deformities of the posterior fossa. They are either evident at birth or even prenatally or become symptomatic during adolescence or adulthood. Diagnosis relies mainly on MRI. Chiari type I is the most common form and is characterized by herniation of the cerebellar tonsils through the foramen magnum and consecutive forward compression of the lower brainstem. Chiari type II mainly combines a caudal herniation of the cerebellar vermis and brainstem, lumbar myelomeningocele, and supratentorial abnormalities typically of the corpus callosum. Chiari type III associates some intracranial defects of Chiari type II with a high cervical meningomyelocele. Chiari type IV is characterized by cerebellar hypoplasia with aplasia of the tentorium cerebelli. Syringomyelia is the most common spinal cord defect found in association with Chiari malformations. About 40–80% of patients with Chiari type I malformations have a syrinx. The central cavitation is usually located at the cervical level, but may extend cranially to the brainstem or caudally to the lower segments of the spinal cord. Asymptomatic patients diagnosed with Chiari type I in the absence of concomitant syringomyelia are not considered as candidates for surgical therapy in most cases. Surgery of symptomatic malformations consists usually in decompression of the foramen magnum. Nonsurgical therapies include management of neuropathic pain, physical therapy, and rehabilitation.
M. Manto (*) Unite´ d’Etude du Mouvement (UEM), FNRS, Neurologie ULB Erasme, 808 Route de Lennik, 1070 Bruxelles, Belgium e-mail: [email protected] H. Christian Department of Neuroradiology, University of Heidelberg, Medical Center, Im Neuenheimer Feld 400, Heidelberg D-69120, Germany e-mail: [email protected] M. Manto, D.L. Gruol, J.D. Schmahmann, N. Koibuchi, F. Rossi (eds.), 1873 Handbook of the Cerebellum and Cerebellar Disorders, DOI 10.1007/978-94-007-1333-8_85, # Springer Science+Business Media Dordrecht 2013
1874
M. Manto and H. Christian
Introduction Chiari malformations represent the most common malformations of the posterior fossa (Manto 2010). They share the presence of anatomical deformations of the brainstem and cerebellum (Schijman 2004). All of them are characterized by a “crowded” foramen magnum, along with a “crowded” posterior fossa whose size may be reduced. The spectrum of clinical manifestations is large, ranging from asymptomatic cases to major neurological disabilities leading to death.
Historical Aspects Historically, the first description of what was called later a Chiari type II (see below) was made by Cleland in 1883, who described a case of spina bifida with hydrocephalus and malformation of the posterior fossa (Peach 1965; Madsen et al. 2002). Chiari described the tonsillar herniation through the foramen magnum characterizing Chiari type I malformation in a 17-year-old woman (Chiari 1891). One year later,
Data Loading...
