Fig 3.

Images obtained in an 86-year-old man with scoliosis and spinal stenosis.

A, In patients such as this one, contrast medium may appear to be within the thecal sac, because it can have a globular shape at the point of injection. In reality, the thecal sac has been displaced to the right, and the patient remained asymptomatic throughout the procedure.

B, An image taken 6 mm inferior from the injection site shows that contrast material spreading within the epidural space, confirming appropriate needle placement.