LAUSR

BACKGROUND Chiari 1 malformation is a structural abnormality of the hindbrain and posterior fossa characterised by herniation of the cerebellar tonsils through the foramen magnum. Although asymptomatic in some cases, hindbrain herniation may be associated with disruption of cerebrospinal fluid flow dynamics at the craniovertebral junction and syrinx formation leading to symptoms. Foramen magnum decompression with or without duraplasty is the most commonly performed surgical procedure in the management of this condition. Management of syringomyelia associated with Chiari malformation is more challenging and controversial. Although associated syrinx can significantly improve following craniovertebral decompression and restoration of cerebrospinal fluid flow, in some cases it persists despite decompressive surgery and may even continue to enlarge. CASE DESCRIPTION We describe a 4 year old boy with non-craniosynostotic Chiari malformation and extensive cervical syrinx who despite foramen magnum decompression and a further revision, continued to deteriorate clinically and radiologically. Posterior calvarial augmentation was performed as a salvage procedure with resolution of tonsillar herniation and syrinx. CONCLUSION Posterior calvarial augmentation is a viable option in Chiari cases refractory to foramen magnum decompression.