Ganglion of Impar Block – Technique and Overview

Name of Procedure

  • Ganglion Impar Block
  • Ganglion of Walther Block
  • Tailbone Block

Sample Opnote


To administer medication around the ganglion of impar.


Usually to treat coccydynia or pain that is mediated by sympathetic nerves from the ganglion impar (such as lower parts of the GI and GU system)



coming soon…


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

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

  1. 25g x 1.5″ hypodermic needle
  2. 3cc 0.25% bupivicaine (with or without steroid) in 3cc syringe
  3. 2cc contrast in 3cc syringe

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 tailbone.


  1. Get a simple lateral view of the coccyx
  2. Place a pointer on either side of the patient to get a sense of where to insert the needle:
    1. You’re inserting the needle midline but you need to know how far superior/inferior to enter. So a pointer at the patient’s side mimicking your desired trajectory can show you where to insert.
    2. You’ll look for a sacrococcygeal segment that looks like a needle can pass through and one that doesn’t require you’re entry point to be too inferior.
  3. Once you know your entry point and trajectory simply insert the 25g hypodermic needle, pass through the sacrococcygeal segment and land the tip just anterior to the bone.
  4. Inject a small amount of contrast to confirm spread:
  1. Use live fluoroscopy to confirm lack of vascular uptake
  2. Inject your medication.


  1. There may be several sacrococcygeal segments available. You want to try to avoid starting too low or you’ll be in an awkward/less clean are for your entry point. Also the lower the segment the more curved it is so you’ll have an awkward trajectory.
  2. Here is another example.
    1. This required a more angled trajectory.
    2. The needle is faintly visible near the bottom of the coccyx.
    3. There may be one more sacrococcygeal segment above that could have worked as well.


Ganglion impar block in patients with chronic coccydynia