Choosing an ICD-10 Code For Low Back Pain

Low back pain is a problem for many a patient. Just how common is it? According to the World Health Organization (WHO), 619 million people globally were affected by low back pain in 2020— making it the most prevalent musculoskeletal condition in the world. What’s worse, the WHO projects that as of 2050 the number of low back pain cases will rise to 843 million worldwide as the global population continues to age. 

Given that trend, rehab therapists are likely to see even more low back pain patients in their physical therapy practice in years to come. That means they need to get up to speed on not only treating low back pain but finding the right ICD-10 codes for the condition. But what's the right diagnosis code, and when should you code for low back pain as opposed to using the ICD-10 code for sciatica? We’re here to explain and hopefully make choosing an ICD-10 code for low back pain a pain-free experience.    

What are the different types of low back pain? 

While patients may only be able to articulate that their lower back hurts and roughly how long it’s bothered them, clinicians know that there are three different types of back pain, as laid out by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS):

• Acute low back pain
• Subacute low back pain
• Chronic low back pain

NIAMS also outlines that chronic low back pain can be caused by several factors, such as:

• Mechanical or structural problems, like strains, sprains, or degenerated or ruptured discs,
• Inflammatory conditions like ankylosing spondylitis, or
• Other conditions like osteoporosis, infections, and back pain in pregnancy.   

What’s the ICD-10 code for low back pain?

Coding for low back pain has changed in recent years. As of a few years ago, therapists could use ICD-10 code M54.5 for low back pain — that is until CMS did away with it as of the 2022 final rule. Given that code M54.5 was one of the more commonly used codes for rehab therapists, something needed to fill the void. That’s why, as part of that update, CMS introduced three separate, more specific ICD-10 codes to replace code M54.5:

• M54.50 (Low back pain, unspecified)
• M54.51 (Vertebrogenic low back pain)
• M54.59 (Other low back pain)

Currently, therapists should be using a new code with low back pain patients and not code M54.5.

When is coding M54.50 appropriate?

As always, the key to coding is using the greatest specificity available. ICD-10 code M54.50 is for low back pain, unspecified. The code descriptor also includes loin pain and lumbago non-organic signs and symptoms (NOS). However, if there is a more specific ICD-10 code for a patient’s condition, you should use that.  

Are there any Excludes1 edits for M54.50?

The Excludes1 edits for M54.50 are: 

• low back strain (S39.012)
• lumbago due to intervertebral disc displacement (M51.2-)
• lumbago with sciatica (M54.4-)

The parent M54 codes also have an Excludes1 edit for psychogenic dorsalgia (F45.41).

When should I use M54.51? 

ICD-10 code M54.51 is intended for vertebrogenic low back pain, which, if you need a refresher, is back pain caused by damage to the vertebral endplates. As described by the Cleveland Clinic, the symptoms of vertebrogenic low back pain are “a deep, burning or aching pain in the middle of their lower back” which can be brought on or aggravated by prolonged sitting or physical activity. 

According to the Cleveland Clinic, some of the causes are:

• A family history of low back pain
• Obesity
• Smoking 
• Physically demanding jobs
• Tallness, and  
• Everyday wear and tear.

Are there any Excludes1 edits for M54.51?

The Excludes1 edits for M54.51 are:

• low back strain (S39.012)
• lumbago due to intervertebral disc displacement (M51.2-)
• lumbago with sciatica (M54.4-)

Because it’s part of the M54 family of codes, M54.51 also has an Excludes1 edit for psychogenic dorsalgia (F45.41).

Is there an instance for using M54.59?

As we mentioned earlier, specificity is key in ICD-10 coding—particularly if you want to get paid by CMS or commercial payers for the care you’re providing without denials or requests for more information. Unfortunately, there’s not much to be found in ICD-10 code M54.59, with a long description of simply “Other low back pain.” Like ICD-10 code M54.50, you would likely only use this code if every other code for back pain and related conditions doesn't fit the bill. 

Are there any Excludes1 edits for M54.59?

The Excludes1 edits for M54.59 are:

• low back strain (S39.012)
• lumbago due to intervertebral disc displacement (M51.2)
• lumbago with sciatica (M54.4)

It also has an Excludes 1 edit for psychogenic dorsalgia (F45.41).

What is lumbago?

If you’ve been in the rehab therapy game for a while, you’ve probably heard the term lumbago — heck, if you’re a younger clinician, you may have heard the term yourself from one of your more seasoned peers.  In essence, it's another term for low back pain that is less commonly used in favor of low back pain. 

However, lumbago is different from sciatica — although you’ll often see the two linked in describing a low back pain patient’s condition. In certain instances, patients experiencing low back pain are also suffering from pain that radiates through the leg, which can be caused by an injury to the sciatic nerve — or sciatica.  

In fact, there are three ICD-10 codes for lumbago with sciatica: 

• M54.40 Lumbago with sciatica, unspecified side
• M54.41 Lumbago with sciatica, right side 
• M54.42 Lumbago with sciatica, left side  

What are the ICD-10 Codes for Low Back Pain Due to Disc Degeneration?

Starting October 1, 2024, the codes M51.36 (other intervertebral disc degeneration, lumbar region) and M51.37 (other intervertebral disc degeneration, lumbosacral region) will be deleted from the ICD-10-CM lexicon and replaced by newer, more specific, codes. 

Why, you ask? Well, the name of the game in ICD-10 coding is all about specificity, and up until this point, the prior codes were anything but specific. So, to remedy that, the Centers for Medicare & Medicaid Services (CMS) and the National Center for Health Statistics (NCHS) are trying to make rehab therapists’ lives a little bit easier—for once. To replace M51.36, the new codes are:

• M51.360 (other intervertebral disc degeneration, lumbar region with discogenic back pain only);
• M51.361 (other intervertebral disc degeneration, lumbar region with lower extremity pain only);
• M51.362 (other intervertebral disc degeneration, lumbar region with discogenic back pain and lower extremity pain); and
• M51.369 (other intervertebral disc degeneration, lumbar region without mention of lumbar back pain or lower extremity pain).

And to replace M51.37, the new codes will be: 

• M51.370 (other intervertebral disc degeneration, lumbosacral region with discogenic back pain only);
• M51.371 (other intervertebral disc degeneration, lumbosacral region with lower extremity pain only);
• M51.372 (other intervertebral disc degeneration, lumbosacral region with discogenic back pain and lower extremity pain); and
• M51.379 (other intervertebral disc degeneration, lumbosacral region without mention of lumbar back pain or lower extremity pain); and
• M62.85 (dysfunction of the multifidus muscles, lumbar region).

You might find it interesting that M62.85 (dysfunction of the multifidus muscles, lumbar region) was added to this list. However, when you consider the relationship between multifidus dysfunction and non-specific low back pain, using this ICD-10-CM code may be your best bet. As always, when using any ICD-10 diagnosis code for physical therapy billing and evaluations, use your clinical judgment, be as specific as possible, and back it up with documentation.

Where can I learn more about sciatica?

Can’t get enough of low back, foot pain, and leg pain conditions? You’re in luck! If you want to read up on sciatica, we have a blog post dedicated to the ICD-10 codes for sciatica as well as additional information about the condition and its treatment.

Hopefully, you're better informed to deal with cases of acute low back pain or chronic low back pain in your physical therapy clinic. If you want to learn more about picking the right diagnosis code, check out our other blogs on the ICD-10 code for difficulty in walking or the ICD-10 code for generalized weakness.