Interspinous Ligament Injection

Question:

Our doctor performed an interspinous Ligament injection L3-4 for the diagnosis of lumbar interspinous bursitis. I billed CPT 20550 but was unable to code the anatomical modifier LT or RT because it was injected directly into the ligament. Would CPT code 22899 be more appropriate, as 20550 requires an anatomical modifier?

Answer:

If an interspinous ligament injection is performed due to bursitis, the correct CPT code would be 20550. Unlisted CPT codes are utilized when a specific CPT code does not exist.

A specific CPT code exists for this procedure therefore, 20550 is used. 

*This response is based on the best information available as of 04/02/26.