Management of Chiari Malformation Type I with Posterior Fossa Decompression without Dural Opening

Object Chiari malformation type I is a condition where there is impaired CSF circulation through the foremen magnum and cerebellar tonsillar herniation on MRI > 5 mm below the foramen magnum, and is often treated by posterior fossa decompression but the controversy exists over whether the dural needs to be opened or not.

Methods Twelve patients were subjected to this study on whom posterior fossa decompression without dural opening were performed. Patients' clinical symptoms and signs and radiological findings were reviewed.

Results Eleven patients (91.6%) showed excelled clinical improvement or even resolution of their symptoms; the remaining patient who did not improve had tonsillar herniation > 9mm

Conclusion Cases of Chiari malformation type I with tonsillar herniation < 9 mm will benefit from posterior fossa decompression without dural opening which avoids major complications.

Keywords Chiari malformation; posterior fossa decompression; non dural opening