Coding for meaningful data: ICD-10-PCS root operations

Root operations are core concepts at the heart of the ICD-10-PCS classification (PCS for short). Root operations are not created equal—some are more narrowly defined than others. It would be great if we could diagram the 31 root operations as a well-proportioned tree, with a single general root operation at the trunk, splitting to a more specific group of “major branch” root operations, and on to a final level of even more specific branches. But we can’t—it’s not that simple. The level of “wiggle room” in a PCS root operation definition varies, such that some root operations can serve as “general” options in certain contexts and “specific” options in others.

Some people use the “root operation groups” for understanding these core concepts. The root operation groups include groupings like “Root operations that always involve a device” and “Root operations that alter the diameter/route of a tubular body part.” The root operation groups help introduce the conceptual framework of PCS, but like anything that creates mental pigeonholes, they are only a starting point, one of several ways of examining the relationships between root operations.

In this blog, I offer another way of looking at PCS root operations, as an interplay between general and specific root operation definitions. Since creating meaningful coded data is all about finding the most specific code to describe the level of effort and risk involved in a procedure, the first question to ask when coding a procedure is, what is the most specific root operation that describes what was done?

Root operations are general or specific in the context of three things: written instruction in the form of PCS coding guidelines/Coding Clinic advice, the operative report itself, and other possible root operations that could be considered.

ICD-10-PCS guidelines and Coding Clinic advice recommend certain root operations as the “default” option when a more specific root operation does not apply. The most commonly used default root operations are Inspection and Repair.

According to the PCS coding guideline B3.3, the root operation Inspection can be coded for situations where a procedure is discontinued before any other root operation has been performed. For example, if a planned thoracoscopic excision of a lung tumor is discontinued because the patient becomes hemodynamically unstable, then the root operation Inspection applies instead of the root operation Excision. This is using the root operation Inspection in its “general” sense, because Inspection is being used to capture some useful information about the site of the procedure (lung) and the level of invasiveness (thoracoscopic) without overstating the outcome of the procedure. Nothing was excised, so the root operation Excision would not be a defensible option in this case, and Inspection is the most specific root operation that describes what was done.

PCS designates the root operation Repair “to be used only when one of the other root operations does not apply,” including when the PCS tables do not include the desired specific root operation. Coding Clinic has made liberal use of this default coding advice, and some of it has become obsolete as the PCS tables are updated. (In these first two update years after implementation, we had work our way through the backlog of changes identified but not implemented because of the code freeze.) For example, procedures to correct congenital cardiac anomalies did not initially have specific root operations available for the body parts being corrected, and so root operation Repair was often used as a default. Many of these scenarios do not have the desired specific root operations available.

Inspection and Repair are not exclusively used as a default. In many situations, they are the Goldilocks option, “just right” for the coding scenario. For example, if the procedure described is a diagnostic bronchoscopy, then Inspection is precisely the root operation to use, and not a default or a compromise at all. By the same token, if the procedure described is suture of a laceration, then Repair is the precisely the root operation to use for that scenario.

In terms of the language, root operations can also be understood as general or specific in relation to each other. I’m going to use the super simple example of a coronary artery bypass graft (CABG for short) to illustrate. The root operation Bypass is the best, most specific root operation to describe a CABG procedure, but I’m going to play devil’s advocate and look at the other candidates.

A CABG could be Repair, since the root operation definition says Repair is “restoring a body part to it anatomical structure and function to the extent possible,” and a CABG is certainly doing that—along with a ton of other procedures. But the explanation that follows the root operation definition says it is to be used only when one of the other root operations does not apply, so Repair is out.  What about the root operation Supplement? It is a bit more specific and it also applies to a CABG. Supplement is defined as Putting in or on biological or synthetic material that physically reinforces and/or augments the function of a portion of a body part. And then there’s Reposition, which works too. Reposition is defined as Moving to its normal location, or other suitable location, all or a portion of a body part.

So why is Bypass the most specific option for describing a CABG, over Reposition and Supplement and Repair? Let’s look at the root operation that describes the procedure. Bypass’ PCS definition spells out the precise objective of root operation and the specific physical method for achieving that objective. The objective of Bypass is to “alter the route of passage of the contents of a tubular body part,” and is achieved by “rerouting the contents [of the body part] to a downstream area” using “one or more anastomoses.” Since all of the key portions of the root operation definition apply (in other words, by assigning this code we aren’t claiming something was done that was in fact not done) and Bypass is clearly more specific than the other options, then Bypass is the root operation to code for a CABG.

Now, no trained coder is going to get hung up on which root operation to choose for a CABG. But something more subtle, like a revision of a “neobladder” conduit, can give even the most experienced coder pause. Coders can tie themselves in knots over choosing the root operation by considering all the possible root operations as equals, but they can untie that knot more easily by focusing their search in this way, by looking for the most specific root operation that describes the procedure.

Next blog, I’ll talk about what the interplay between general and specific root operations means for the coded data—what you can and can’t know from the data.

Rhonda Butler is a clinical research manager with 3M Health Information Systems.