Epidural Contrast Patterns and Clinical Implications: An Educational Review.

Purpose of review: The purpose of this educational review is to describe the contrast spread patterns that indicate accurate needle placement in the epidural space and spread patterns associated with erroneous needle insertion.

Recent findings: Epidural injections are minimally invasive and commonly used for patients with acute and chronic back pain that does not respond to conservative management. Imaging with contrast is frequently used during this procedure to improve accuracy and reduce adverse events. Contrast spread patterns are an important tool that can help identify where the needle is placed and whether the placement is accurate. Despite this, there may be discrepancies in the interpretation of spread patterns which ultimately reduce the utility of contrast. Inaccurate needle placement may result in intrathecal/subarachnoid, subdural, fascial, or retrodural space of Okada injections. The correct interpretation of contrast spread patterns on imaging is crucial for confirming accurate epidural needle placement. Furthermore, understanding contrast patterns of improper needle placement can prevent adverse events that result from injection outside of the epidural space.