Basilar invagination and Chiari malformation associated with cerebellar atrophy: report of two treated cases

We report two patients with an unusual complex of anomalies wherein the basilar invagination and Chiari malformation was associated with marked cerebellar atrophy. Both patients presented with relatively severe lower cranial nerve deficits and showed clinical improvement following a posterior foramen magnum bony decompression. The pathogenesis of the anomalies is discussed and the rationale of treatment is analysed.