Foramen magnum decompression in adults with Chiari type 1 malformation: use of intraoperative ultrasound to guide extent of surgery.

Background: Foramen magnum decompression (FMD) is an established technique for patients with Chiari-1 malformation. However, the extent of decompressive surgery is controversial, in particular whether dural opening is undertaken.

Objective: In this study, we report outcomes with our technique utilising intraoperative ultrasound (iOU) findings.