Coding for the Subluxation: ICD-9 vs. ICD-10

By Evan Gwilliam, DC, MBA, CPC

When I attended chiropractic school, I was taught that chiropractors approach health care differently than the traditional medical establishment. I was instructed to seek out the so-called "vertebral subluxation complex" or "VSC" and remove it, thus allowing the body to heal itself. This lesion, and its treatment, were reserved for only the chiropractic profession. Later, I became a certified professional coder and became well-acquainted with ICD-9 codes. So, naturally, I took a closer look at the 739 codes chiropractors use for the subluxation. What I found is a little murky, particularly in how they translate to the ICD-10 code set.

The Subluxation and ICD-9

It turns out that the official definition of 739 codes is "nonallopathic lesions, not elsewhere classified." The term nonallopathic is not found in any major medical dictionaries, but allopathy is recognized as traditional or organized medicine. The phrase "not elsewhere classified" (or NEC) is used when the medical record provides detail for which a specific code does not exist (ICD-9 coding guidelines, section I.A.5.a).

In other words, 739 is a code that does not describe a subluxation. It does not even say what the patient has; it says that there is no code to describe what the patient has.

Fortunately, the inclusion notes in the tabular list provide a little more clarification. They say the code includes somatic and segmental dysfunction. This helps clarify it a little, but it is safe to assume that my chiropractic college professors were not consulted when this code description was written.

Certified professional coders are taught to code by looking up the words for the diagnosis in the alphabetic index and then confirming the code in the tabular list of ICD-9. None of the terms in the description for 739 appears in the alphabetic index, making it hard for a non-chiropractic coder to intuitively find the right code for the "subluxation."

However, there is a heading under the word subluxation. Unfortunately, the instructions there say "see also dislocation" and the only choice that mentions vertebra refers the coder to "fractures," neither of which are in the within the scope of chiropractic care.

Most medical dictionaries simply define a subluxation as "partial dislocation" or "significant structural displacement," and that appears to be the way it is used in ICD-9. While the World Health Organization recognizes that a "chiropractic subluxation" is different, clearly the elusive "vertebral subluxation complex" I learned about in school has no place in the ICD-9 code set. All we get is 739, which is a code for conditions that do not have a code.

The ICD-9 allopathic "subluxation" is more in line with the "partial dislocation" viewpoint, which is usually treated by medical doctors with medication and/or immobilization. Medicare, which tells most chiropractors to use the 739 codes for subluxations, defines it reasonably well on behalf of the chiropractic profession:

"A motion segment, in which alignment, movement integrity and/or physiological function of the spine are altered although contact between joint surfaces remains intact. For the purposes of Medicare, subluxation means an incomplete dislocation, off-centering, misalignment, fixation, or abnormal spacing of the vertebra anatomically."

Put more simply, it is a condition of minor, sometimes painful, misalignment that is treatable by manipulation. ICD-9 has never provided a code that truly describes this and differentiates between the chiropractic subluxation and the allopathic subluxation. Chiropractors have been compelled to try to fit a square peg into a round hole for many years.

The Subluxation and ICD-10

ICD-10 contains five times as many codes as ICD-9 and at first glance, appears to be a chiropractic coder's dream. It offers a wide range of new possibilities; however, the jury is still out on the way these codes will be used by payers.

ICD-10 code equivalents can be found by several methods, including translation from ICD-9 to ICD-10 using a GEMs [General Equivalency Mappings] code map, and looking up the terms in the alphabetic index.

According to GEMs (courtesy of the National Center for Health Statistics and the free smartphone app "Find-A-Code"), the commonly used ICD-9 code of 739.1 (Nonallopathic lesions, NEC; cervical region cervicothoracic region), is approximate to M99.01. This M99.0_ group of codes is listed on the future drafts of most Medicare Local Coverage Determinations, and is therefore very likely to be the official replacement for 739. The only difference in the description is that the word nonallopathic is replaced with biomechanical. While this is an improvement, it still differs little from ICD-9 and does not use "subluxation," as taught to me in school.

It turns out that chiropractors were able to provide input into ICD-10 codes because nearby, we find the code M99.11, which is defined as "subluxation complex (vertebral) of the cervical region." At first, it appears this is the solution; finally, coders and chiropractors can get along in perfect harmony. This code uses the words taught by chiropractic college instructors.

Unfortunately, GEMs points this code back to 839.00, not 739.1, in ICD-9. 839 codes are for "other, multiple, and ill-defined dislocations" and 839.00 is the code for "closed dislocation, cervical vertebra, unspecified."

In other words the new "chiropractic subluxation" code of M99.1_ in ICD-10 does not map to the old "chiropractic subluxation" code of 739 in ICD-9. Instead, the word subluxation leads the coder to the "closed dislocation" of the 839 codes.

When the government put together the GEMs crosswalk, it did not consider the chiropractic definition of "subluxation", and it still doesn't recognize it in the new codes. Hence, few payers are likely to allow this M99.1_ code. It does not show up in any of the Medicare coverage drafts, so it may be most useful when used internally to record diagnoses for patients on wellness care.

If we turn to "subluxation" in the alphabetic index in ICD-10, we are actually not led to the M99 codes at all. It says, "See also dislocation," which implies that the medical lexicon still applies in ICD-10. However, under the subheading of "vertebral," we learn that ICD-10 separates the codes into two groups: recurrent and traumatic.

The recurrent category is M43.5_ (other recurrent vertebral dislocation). The instructional notes in the tabular list say, "Excludes biomechanical lesions NEC M99._ _." This means a patient may have one diagnosis or the other, but never both. Drafts of Medicare guidelines do not include the M43.5_ _ as a code chiropractors can use, probably because it is intended for medical intervention.

The traumatic vertebral subluxation codes, S13 (cervical), S23 (thoracic), and S33 (lumbar), use the words subluxation and vertebra in their descriptions. When all seven characters of the code are selected, they provide information about the specific spinal level, whether it is a subluxation or dislocation, and whether the encounter is the initial or a follow-up visit. This is detail that chiropractic physicians have never been able to report using ICD-9.

However, GEMs points these codes back to the 839 category, rather than the 739 category in ICD-9. If you use 839s for some payers now, then you will likely use these "S" codes when we transition to ICD-10. However, it is also possible that these codes may be intended for use by allopathic physicians for dislocations, rather than for the "chiropractic subluxation," since all the chapter 19 "S" codes in ICD-10 are for traumatic injuries.

So, Which Codes Should You Use?

The most likely scenario is that M99.0_ will replace 739; and S13, S23, and S33 will replace 839. However, payers will have to determine which codes will properly document medical necessity, and this is the big mystery. They have their business rules encoded for ICD-9 and limited information is available to providers about what payers will do with all of these new options in ICD-10.

Will payers be able to apply old decision logic to these new codes? Chiropractic coders probably won't find out until they submit the first claims after the ICD-10 implementation date. We will just have to wait and hope the subluxations we have been diagnosing all these years will finally be reportable with ICD-10-CM.

Dr. Evan Gwilliam graduated as valedictorian from Palmer College of Chiropractic in 2003 and later earned a master's of business administration. He is the only chiropractic physician who is also an AAPC-certified ICD-10 instructor and sits on the editorial board for He is also a certified professional coder, medical compliance specialist and certified professional medical auditor; and speaks on compliance and coding topics all over the country as vice president of the ChiroCode Institute. He can be reached at .

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