Intraoperative ultrasound / intraoperative MRI

What it is

Intraoperative ultrasound and intraoperative MRI are imaging tools used during Chiari surgery to assess the decompression and CSF flow in real time. They help the surgeon confirm whether the surgical goal — restoring CSF flow — is being met and whether further steps are needed.

Understanding Intraoperative ultrasound / intraoperative MRI

After the bony decompression, the surgeon can use intraoperative ultrasound (a probe placed in the surgical field) to see the tonsils and assess CSF flow around them, or, in some centers, intraoperative MRI. This real-time information can help decide whether the decompression is sufficient or whether additional steps (such as opening the dura, adding a duraplasty, or reducing the tonsils) are needed to achieve good CSF flow. Some surgeons use intraoperative imaging to tailor the extent of surgery to each patient, potentially avoiding unnecessary steps while ensuring the goal is met. (Of note, the patient's position during surgery can affect flow, which surgeons take into account.) Understanding intraoperative imaging clarifies how surgeons can assess and guide the decompression during the operation.

Why it matters

Understanding intraoperative imaging helps families see how surgeons can check CSF flow during the operation to confirm the decompression is adequate and decide whether additional steps are needed — tailoring the surgery.