Brachial plexus injuries coding help!!!


Irvine, CA
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Hello! Are there any experienced Plastic Surgery coders on here or anyone who is very familiar with coding for brachial plexus injury codes? I am trying to understand not only how to bill these cases, but how to bill the number of units. I get so many denials for exceeding number of units. Any help is appreciated. Some CPT codes that we use often are:

and usually with multiple units on each.


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These are complex procedures and redacted op notes would be needed to provide guidance on exact codes and units for a given procedure. However, a good place to start would be with the Maximum Unit Edits (MUEs) published by Medicare. You can access them here:,the improper payment rate for Part B claims. Once you get to the web page, you can click on the "Practitioner Services MUE Table - Effective 10-01-2020" link in the downloads box to view the latest MUEs that will go into effect this week.

MUEs are helpful because they can tell you whether more than 1 unit of a code is permitted, and if so, how many units are generally expected.

  • For 64861, the MUE is 1 unit and the MAI indicator (reason for edit) is "2: Date of Service." That is a binding edit for Medicare and payers following their rules. This means that you will never receive payment for more than 1 unit of that code on a given DOS and coding more than 1 unit is considered a coding error based on the code definition or Medicare policy. So I would not report more than 1 unit on 64861.
  • For CPT 64856 and 64901, the MUE is 2 units with an MAI indicator of "3: Date of Service." This means that Medicare would generally not expect to see more than 2 units of each of these codes reported on any given date of service but in rare cases where documentation supports coding in excess of that MUE, you can report more than 2 units. If you find yourself routinely reporting more than 2 units, though, that is a prompt to pause and verify understanding of the code and the documentation (it is possible but not likely to appropriately report more than 2 units regularly based on the definition of the code and CMS policy). If you do have documentation to support more than 2 units of each code, suggest reporting up to 2 units on a single line and then the additional units on a separate line with a modifier 59 (e.g., 64856 x2 and 64856.59 x1). This will allow your first 2 units which are usually not denied to pay cleanly and then let you appeal the denial for the third unit and beyond with notes. You will always get an initial denial if you code in excess of MUEs with an MAI indicator of "3: Date of Service" because what is being reported is not typical- from there, you have to support your code with documentation on appeal.
  • For CPT 64902, the MUE is 1 unit with an MAI indicator of "3: Date of Service." Same payment rules as noted above for 64856 and 64901. If you find yourself routinely coding more than 1 unit, take a pause and make sure that is correct. If it is, suggest 64902 x1 on one line and 64902 x ___ (units) with a modifier 59 on a separate line to allow the claims process to play out as smoothly as possible.
I hope that helps :)