Fluoroscopic Guided Caudal Epidural Steroid Injection – Technique and Overview

Name of Procedure

Caudal Epidural Steroid Injection (ESI)

Sample Opnote


To access the epidural space via a caudal approach. The primary goal for this approach is to cover sacral nerves.


  1. Typical epidural indications such as administration of steroid for chronic pain (sciatica, herniated discs, etc), administration of blood in a blood patch
  2. Local surgical anesthesia



The relevant structures for this procedure are the sacral canal and sacral hiatus, outlined in the diagrams. The sacrococcygeal ligament covers the hiatus and you might feel this ligament as you pop through it.

Of note, the subarachnoid and subdural spaces typically stop around S1-S3, and so the needle tip placement is usually below about S3.

So, entering midline and inferiorly with a steep trajectory can get you into the canal as you “walk up” the posterior border of the sacrum. (red line)


Core Equipment/Disposables: See our disposables/equipment article for “core” items that are common to all procedures.

Core Skills: See our guides to obtain images of the cervical, thoracic, or lumbar spine. Then steer a needle to direct it under the skin.

Special items and suggested setup for this procedure (see quick guide video above for example tray prep):

  • 20g x 3.5″ Tuohy epidural needle
  • 3-5cc normal saline or air in a LOR syringe
  • Steroid + 10cc of normal saline in a 10cc syringe as your injectate
  • 2-3cc contrast in a 3cc syringe
  • 3-5cc 1% lidocaine in a 5cc syringe with a 25g x 1.5″ hypodermic needle for subcutaneous local anesthesia.

Landmarks and Patient Positioning

Position the patient in a basic prone position so that the bottom of the c-arm can go under the table below the sacrum and coccyx.


Although this can be done blind, we’ll focus on a fluoroscopic approach.

  1. You can try to palpate the sacral cornua (as typically taught) and feel for the hiatus in between, but it shouldn’t be necessary.
  2. First, determine how far inferior to enter and what trajectory to use to get the needle tip into the sacral hiatus
    1. Start in a lateral view (use the diagram above and compare to the real images below)
    2. In a lateral view, place a long pointer on the left or right side of the patient. The goal is for the pointer to find an entry point well below the hiatus that will allow for a steep trajectory.
    3. From here, you’ll simply enter at the same point and with the same trajectory, but in the midline.
    4. The blue line is about how your pointer will be oriented, and hence the green dot is your entry point (but in the midline). This gives you a trajectory to the canal (red line).
    5. In the images below the needle is acting as a pointer.
  1. Anesthetize the skin aiming towards the hiatus. 
    1. An image with the 25g needle inserted can help you to gauge depth and trajectory
  2. Insert your epidural needle
    1. Under lateral fluoroscopic guidance direct the needle to the bone just below the sacral hiatus.
    2. Once you contact bone, you can walk superiorly to place the needle through the hiatus and into the sacral canal
    3. You can advance using a normal loss of resistance technique with a Tuohy needle
  3. Once in the epidural space, inject contrast to determine spread in the epidural space.
  1. Inject desired medication (Usually a higher volume to allow spread to higher levels)


  1. As noted above you’ll advance the needle in the sacral canal. Keeping the needle tip below about S3 can help reduce the risk of dural puncture. This will require an AP view.


  1. Caudal Anesthesia
    1. Excellent, thorough topic review along with some images and procedure description
    2. Also includes other techniques such as blind and ultrasound guided.
  2. Caudal epidural injection 
    1. Some topic review and technique description but no photos
  3. Caudal Epidural Block: An Updated Review of Anatomy and Techniques
    1. Good diagrammatic anatomy review of the sacrum, sacral canal, dura, sacral hiatus 
    2. Brief technique descriptions for for blind, fluoroscopic and ultrasound guided
  4. Epidural Steroid Injections – StatPearls
    1. Brief review of epidurals and caudal technique