Below they describe injection of painful scar tissue as 64999. In contrast, below is stating for a scar neuroma injection to use 64450. I couldn't find when 11900 it is suggested to be used for scar injections .
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AMA CPT Assistant September 2010 page 10
Surgery: Nervous System, 64999 (Q&A)
Question: The patient has postmastectomy pain in the scar tissue area and not in the muscle. An injection was performed into the scar tissue of the chest area using a mixture of triamcinolone topical, lidocaine with epinephrine, and bupivacaine hydrochloride with epinephrine. What CPT code should be reported for this procedure?
Answer: Injection of painful scar tissue is reported using CPT code 64999, Unlisted procedure, nervous system. When reporting an unlisted code to describe a procedure or service, it is necessary to submit supporting documentation (eg, procedure report) along with the claim to provide an adequate description of the nature, extent, and need for the procedure, and the time, effort, and equipment necessary to provide the service.
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https://www.aapc.com/memberarea/forums/showthread.php?t=16475
Inquiry Question:
What is the best code for a Scar Neuroma Injection?
11900?
64640?
64999?
Please be advised that your inquiry was forwarded to our CPT Advisor representing the American Academy of Pain Medicine for review. Based solely upon the information provided in your electronic inquiry, from a CPT coding perspective and per our CPT Advisor, ?It would be appropriate to report a nerve block injection code for the anatomic site involved or a destruction code if neurolysis is the goal. Most specifically, CPT codes 64450, Injection, anesthetic agent; other peripheral nerve or branch, or 64640, Destruction bby neurolytic agent; other peripheral nerve or branch, for this injection(s), since these codes respectively address the additional work of an injection of an anesthetic agent (nerve block), neurolytic or sclerosing agent into the peripheral nerves.