Coding for Low Back Pain | Blog

Coding for Low Back Pain

Low Back Pain is one of the most common Chief Complaints and problems by patients presenting to physicians in general and to Orthopedic Surgeons in the practice of general orthopedics, right up there with knee pain and shoulder pain. For practical purposes, at some point in their life, most everybody suffers an episode of lower back pain. Much of the introduction to this Blog is spent discussing the anatomy of the lower back, and its complexities. This discussion may seem excessive to Coders, but it also helps explain why the exact diagnosis for the cause of the low back pain is so difficult to zero in on. When I refer to the topic of Low Back Pain, I am including the Thoracolumbar Spine (functionally from T11-L2), the Lumbar Spine (L1-L5), the Lumbosacral Spine/junction (L5-S1), the Sacrum, and the Sacroiliac Joints. All of these areas can be the source of low back pain. Although technically the Thoracolumbar Spine includes T12 and L1, from a functional standpoint I consider the thoracolumbar spine/junction/region to include T11, T12, L1, and L2. The ribs of the T11 and T12 vertebrae do not have a direct anatomical connection of the rest of the rib cage (T1-T10). The rib cage contributes to the stability of the Thoracic Spine, but since the lower 2 ribs are not connected to the rib cage, they do not provide the same additional support and stability to T11 and T12. In that respect, the T11 and T12 vertebrae function more like Lumbar Spine vertebrae. This is a segment of the spine that transitions from the more stable, less mobile Thoracic Spine (T1-T10) to the more mobile and flexible Lumbar Spine. Also, this is the transition zone from the dorsal kyphotic curve of the Thoracic Spine to the lordotic curve of the Lumbar Spine and Sacrum. Because of these transitions, this segment of the spine can be exposed to greater stresses and strains. In the Lumbar Spine, normally there are 5 lumbar vertebrae. However, during the development of the lower lumbar spine and its junction with the sacrum (which is several fused vertebral segments), variations in the anatomy do occur. Occasionally the 5th Lumbar vertebra can be partially or completely fused to the Sacrum in such a way that it functions more as a Sacral vertebra than a Lumbar vertebra. This is considered incomplete segmentation of the spine. In the situation sited, this is referred to as “Sacralization of L5.” At the other end of the spectrum is another developmental segmentation problem in which the 1st Sacral vertebrae is not completely fused or incorporated into the sacrum, and from a functional standpoint functions more like a 6th Lumbar vertebra. This variation is referred to as “Lumbarization of S1.” There are also some developmental abnormalities in the completion of the development and closure of the bony neural arch such that it does not completely close, which is Spinal Bifida. Most commonly this is very limited to about the S1 level and is called Spina Bifida Occulta. This is often seen on x-rays of the lumbar and sacral spine, but in this very limited form is not a cause of low back pain. The more extreme version of Spina Bifida can cover several segments of the lumbar and sacral spine with associated meningomyelocele, and which can cause devastating neurologic and orthopedic problems. These appear at birth and require immediate surgical attention. Another significant aspect of the anatomy of the spine, both from the neurologic and the skeletal aspect, is that the spinal cord does not go the entire length of the spine. It generally terminates at about the level of L1 and beyond that point is converted into the nerve roots of the Lumbar and Sacral spine, called the Cauda Equina. This means that from about T12-L1 on down through the remaining Lumbar Spine, disorders of the Lumbar Spine affect only the nerve roots, not the spinal cord itself. Therefore, Myelopathy which is neurologic damage to the spinal cord can only occur in the cervical and thoracic regions down to the terminal spinal cord at L1. Myelopathy cannot occur where there is no spinal cord. However, Radiculopathy, which is damage to the spinal nerve roots (radicals) can occur at any level of the spine. However, since there is no spinal cord in the Lumbar Spinal Canal, disorders of the lumbar spine can only result in radicular problems such as radiculitis or radiculopathy. As stated, although this may seem to be an excessive amount of “education” regarding anatomy, it helps explain the difficulty in accurately identifying the cause of a patient’s low back pain, i.e. with specificity.

From the standpoint of the incidence of Low Back Pain, Idiopathic Low Back Pain, which essentially means back pain for which we cannot identify a specific cause, is the most common. This would be coded as a Regional Pain. Often however there is associated muscular involvement resulting in muscular pain (myalgia, myofascial), with or without associated muscle spasm. But, muscular pain and/or spasm can be the “primary” abnormality/element of the back pain (i.e. the cause), or the muscular pain and spasm can be “secondary,” i.e. the result of some other spinal or associated soft tissue disorder or disease. That disorder causes the pain, but the muscles are recruited into the process as they are activated and work to help support and protect the injured bone or soft tissue. It is sometimes impossible to determine whether the muscular involvement is primary or secondary. This makes “Low Back Pain with Muscular Pain and/or Spasm” a common diagnosis. The other frequent elements or causes of Low Back Pain are Intervertebral Disc Disorders, with or without nerve root or radicular involvement. This would include such things as disc degeneration and disc herniations, ruptures, protrusions, extrusions (which are included in the term “displacement“ in ICD-10). "Bulging disc” is a mild form of early disc degeneration, but according to most authorities is not considered a symptom causing lesion. In other words, if a patient suffers from low back pain, it is not the result of a “bulging disc.” With time and as a result of the aging process degenerative processes occur through the lower spine leading to Arthritis/Spondylosis of the spine. Spondylosis/Spondylopathy is the term used in ICD-10. The wear and tear and degenerative processes in the spine can affect all the anatomic elements including the discs, the vertebral bodies (spurs and spur formation), facet joints, and other soft tissues and ligaments that can then cause pain in and of themselves, and stenosis of the spinal canal and/or the neural foramina which can affect the nerves as they pass down the spinal canal or as they exit through the foramina to go out to the rest of the body, i..e. radicular involvement.

In the process of coding for Low Back Pain, which is also/sometimes called Lumbago, the most generic code for this Regional, Site of Pain, comes from Dorsalgia (Other Dorsopathies) and comes from the M54 Code Set. The Code for Low Back Pain is M54.5 (Lumbago NOS), which Excludes strain, disc disorders, and Lumbago with Sciatica (M54.4). This is the code that would apply to Idiopathic Low Back Pain, the Regional Pain in the lower back, which may be an isolated phenomenon, without any other identifiable spinal or soft tissue disorder causing or contributing to the back pain. There are other codes in the Dorsalgia Code Set that add to the confusion of coding for Low Back Pain. There is code M54.3: Sciatica/Sciatic Neuropathy, but this Excludes Disc Disorders as a cause. Isolated Sciatica can occur, but rarely as an isolated phenomenon not caused by some other disorder. Then there is M54.4: Lumbago with sciatica, but this also Excludes Intervertebral Disc Disorders. This code/diagnosis is too vague and nonspecific to be very useful when compared to the more specific codes from the M51 Code Set: Thoracic, Thoracolumbar, Lumbar, and Lumbosacral Intervertebral Disc Disorders with myelopathy (M51.0 ), with radiculitis or radiculopathy (M51.1 ), Disc “Displacement" (M51.2 ) which includes disc herniation, rupture, protrusion, and extrusion, and Disc Degeneration (M51.3 ). Of course, there is always “Other" (M51.4 ) which literally means something other than the above. One of the codes in the Dorsalgia Code Set is M54.0: “Panniculitis,” which literally means “inflammation of the subcutaneous fat characterized by the development of single or multiple subcutaneous nodules.” Many patients have tender subcutaneous “nodules" in the lumbosacral region. I do not know whether these are fatty or fibrous nodules. In 40 years of clinical practice, I have never used the term Panniculitis as an explanation of the patient's low back pain. As it refers to the Dorsalgia Code Set, the 5th Characters are 5 for the Thoracolumbar Spine, 6 for the Lumbar Spine, 7 for the Lumbosacral Spine/junction, and 8 for the Sacral Spine. Although I will discuss muscular and soft tissue aspects of low back pain later in this Blog, it is important to note that more often than not there is not a single diagnosis or code that can be used for coding Low Back Pain. Often it will require a list of codes starting with the generic code for Low Back Pain and supplemented by other codes that may either indicate associated findings such as muscular pain or spasm, or other diagnoses that could be possible or contributing causes for the back pain. In other words the coding may result in something like "Low Back Pain with or associated with…” It may be impossible with a list of several possible/probable contributing problems to prioritize them accurately.

The next major category of Spinal Disorders is the Deforming Dorsopathies (M40-M43) which Includes Kyphosis and Lordosis (M40), but which Excludes Congenital (Q76) and Post-procedural Deformities (M96); Scoliosis (M41) (which Excludes Congenital forms (Q codes) and Post-procedural Deformities (M96), but Includes Infantile (M41.0), Juvenile and Adolescent (M41.1), Other Idiopathic (M41.2), Thoracogenic (M41.35 for the TL spine), Neuromuscular (M41.4), “Other” Secondary (M41.5), and finally “Other" Forms (M41.8) of Scoliosis. During the ages of growth and development, these deformities are not necessarily a cause of back pain, but as time and aging occur, the spine starts to degenerate as result from these deformities, and then these can evolve into secondary spondylopathies/arthritis of the spine in adulthood that can be a source of back pain.

Next, comes Spinal Osteochondroses (Osteochondritis) (M42). The only one of any relevance is Scheuermann's disease (Juvenile Osteochondrosis of the Spine) seen during the teenage years and more frequently in boys than girls, and most commonly occurs in the mid and lower Thoracic Spine, but can go into the upper Lumbar Spine. This can be a source of back pain. It causes a Kyphotic “hump" of the back best seen when the patient bends forward, and particularly when viewed from the side. The "Inflammation” (Chondritis) involves the vertebral body at the epiphyseal rings resulting in abnormal growth of the vertebral body resulting in wedging deformities of the vertebrae. This causes the kyphotic “hump."

In the M43 Code Set for Other Deforming Dorsopathies, are the codes for Spondylolysis and Spondylolisthesis. The code for Spondylolysis is M43.0, which Excludes Congenital Spondylolysis (Q76.2) and Spondylolisthesis (M43.1). Spondylolysis is a defect in the bony ring (neural arch) surrounding the spinal canal that can be a cause of pain, and can result in spinal instability Spondylolisthesis (M43.1), which is a displacement (slippage) of the vertebrae above with the defect in relation to the vertebrae below without this bony defect. There are different gradations (I-IV) which designate the progression from mild to severe, depending on the amount of displacement. This can be painful, but surprisingly, not always. The most common levels involved are L5-S1, followed by L4-L5, and far less frequently above this level. There is a type of Acquired Spondylolysis, but rarely with any listhesis (displacement) which has been identified in young adult athletes, particularly gymnasts and college level football players. This has been categorized as a "Stress Fracture” of the neural arch, i.e. Spondylolysis. This is most common in the low lumbar spine, and would be coded from the M48.4 Code Set (M48.46X for the Lumbar Spine above L5, and M48.47X for the Lumbosacral Spine, which would involve the L5 vertebrae). This particular Code Set requires 7 characters to complete the code, with options of A, D, G, or S. Another code from the M43 Code Set is M43.24: “Spontaneous" Spinal Fusion, which can occur in the lumbar spine, but is very rare, and more often than not, is the result of advanced and aggressive arthritic processes such as Hypertrophic Spondylopathy (M48.1). This “Spontaneous Fusion” results from bony spurs from the vertebral body margin that bridge over the intervening disc space and unite with the spurs from the adjacent vertebra.

The next group would be the Spondylopathies (M45-M49), Arthritis of the spine. M45.0 is for Ankylosing Spondylitis, which is isolated Rheumatoid Arthritis of the Spine. It is a variation of Rheumatoid Arthritis, but isolated to the spine. Rheumatoid Arthritis is a generalized disorder of the body, but can affect the spine, most significantly and severely in the cervical region. As for Ankylosing Spondylitis, it generally starts in the sacroiliac regions then progresses upward through the entire spine all the way to the skull when the process is complete. It can result in significant pain and deformity of the spine. The M46 Code Set applies to "Other" Inflammatory or Infectious Spondylopathies. These are usually a manifestation of a systemic inflammatory or infectious disease which has some spinal involvement. However, occasionally some of these disorders such as Osteomyelitis and Pyogenic and/or Non-pyogenic Discitis can occur as isolated spinal disorders causing pain. M46.2 is for Vertebral Osteomyelitis. M46.3 is for Pyogenic Discitis, i.e. result of a bacterial infection of the disc. M46.4 is for Non-pyogenic Discitis, which is a Discitis for which an infectious agent cannot be confirmed. M46.5 is for Other Infectious Spondylopathies, and M46.8 is for Other Specified Inflammatory Spondylopathies. These again would tend to be spinal manifestations of a systemic disease either inflammatory or infectious. If it as an infection, the infectious disease and/or infecting agent would also have to be coded.

A Code Set M47 is for Spondylosis, which is Degenerative Arthritis of the Spine, which is very common, and when compared to the disorders discussed above for M45 and M46, is the most common degenerative disorder of the spine. The most common is M47.8: Other Spondylosis, without myelopathy or radiculopathy, i.e. without neurologic involvement. As it regards Spondylosis with Myelopathy (spinal cord compression) (M47.1), this can only occur at the T11-T12-L1 segments, as that is the only level of the lower spine for this discussion which contains the terminal end of the spinal cord. Therefore, this would be limited to M47.15 for the T11 or T12 level, and M47.16 for the L1 level. Spondylosis with Radiculopathy (nerve damage) is M47.2 , with a 5th Character of 5, 6, or 7 as previously defined. This causes neuritic pain originating in the lower back and extending into the lower extremity (Sciatica or Femoral Neuropathy). As an isolated disorder, Spondylosis rarely does this on its own, but as a part of other aspects of spinal degeneration that all add up and combined to result in nerve compression. These include the "Other" Spondylopathies of the M48 Code Set, and in particular Spinal Stenosis (M48.0 ), possibly Ankylosing Hyperostosis (M48.1 ), and Traumatic Spondylopathy (M48.3 ). I would be careful using M48.3 unless the previous “trauma" is vague and ill-defined. There may be a history of “trauma” which resulted in the Traumatic Spondylopathy which if identifiable should also be coded. Also, Disc Disorders in the Other Dorsopathies (M51 Code Set) can go along with these Spondylosis disorders. This would include Disc Disorder with Myelopathy (M51.0 ) (T11-T12, T12-L1 only), with Radiculopathy (M51.1 ), and Disc "Displacement" (M51.2 (which includes disc rupture, herniation, extrusion, and protrusion), and Degenerative Disc Disorder (M51.3 ). It may take multiple codes from these code sets to adequately cover all the possible/probable causes of the Low Back Pain, with or without neural involvement, as more than one may be at play.

Fatigue/Stress Fractures of the vertebrae (Code Set M48.4) are very rare in normal, healthy bone such that these would be rare in the lower back region. Furthermore, this Code Set Excludes all forms of pathologic fractures. The only one that I think would fit into this category is the one described previously in the paragraph regarding Spondylolysis. As stated there, in young adult athletes with healthy bone an Acquired Spondylolysis has been identified. This is considered by most of the people that have studied it to be a Stress Fracture of the bony vertebral arch. From what I know about this, it occurs most commonly at the L5 level, which is part of the lumbosacral segment of the spine, and would be coded as M408.47X . If it were to occur at the L4 level or above, it would be M48.46X . As also stated before, these require a 7th Character of A, D, G, or S.

As for the Code Set M48.5: Collapse/Wedge Compression Vertebral Fracture, this is not a particularly useful Code Set in the lower back either because this code set confines itself to this occurring in basically normal healthy bone. This Code Set Excludes current injury or trauma (S codes), all forms of pathologic fractures, and Stress/Fatigue Fractures (M48.4). These codes imply that "normal, healthy” vertebral bone fractured “spontaneously” during normal daily levels of activity. For practical purposes, this does not really happen in the Thoacolumbar, Lumbar, or Lumbosacral Spine. If a vertebral fracture of this type is identified, then you would have to look for some other underlying disease process, i.e. a pathologic process/fracture, or some traumatic insult of sufficient magnitude to cause normal bone to collapse (S Code).

When it comes to Soft Tissue Causes (M60-M79), the Code Set of M60: Myositis, which is "inflammation" of the muscle, has some application to lower back pain. Myositis can be the result of an infectious process (M60.0), non-infectious or sterile myositis (M60.1), or secondary to an intramuscular embedded foreign body (M60.2) such as a residual foreign body from a gunshot wound, etc. These could cause low back pain. The most useful of this Code Set would be in M62.8: Other Specified Disorders of Muscles, and in particular M62.830: Muscle Spasm or Cramp of the back. As for Synovial and/or Tendinous problems (M65-M67), there is really nothing that I can identify that is really relevant/useful to coding Low Back Pain. In Other Soft Tissue Disorders (M70-M79), there is the M70 Codes Set which includes Occupational Disorders for Pain secondary to use, overuse, and pressure, i.e. Occupational Low Back Pain for which there is no other clearly identifiable cause of the low back pain other than the stresses of work activities by the patient, particularly repetitive spinal motions. The code for this would be M70.88, with the 5th Character 8 standing for “other site”, i.e. the low back. This code also requires an Activity Code from the Y93 Code Set. Then there is good old plain “Muscular Pain” from M79.1, which includes Myalgia and Myofascial Pain (Syndrome), but Excludes Fibromyalgia (M79.7) and Myositis (M60.). Myalgia as such is not particularly specific so I would not use it as an isolated or primary code for low back pain. Myalgia has to be differentiated from Fibromyalgia (M79.7) (which is also called fibromyositis, myofibrositis, or fibrositis). Fibromyalgia is a more generalized pain disorder involving multiple areas of the back including the neck and shoulders, upper back, and can include the low back and hip regions. Confusion arises from the mixture of terms that are used. Many physicians will use the term Myofascial Pain (without necessarily including Syndrome) as a diagnosis, even though there is no identifiable pathology of the muscle or fascia, and the term just means there is localized muscle and/or fascial pain and tenderness. Others may use such terms as Localized Fasciitis or Fibrositis for the same thing. The M79.1 code is for localized muscle fascia pain and tenderness, whereas M79.7 is for the more generalized disorder of which localized findings in the lower back and hips may be just a part of the whole picture.

In the category of Osteopathies (M80-M85), there are a large group of disorders that can cause Low Back Pain, in particular the Pathologic Fractures that occur from Osteoporosis (M80.0) for Age-related Osteoporosis including Involutional, Postmenopausal, and Senile Osteoporosis; M80.84 Other Osteoporosis (i.e. Secondary Osteoporosis), and M84.4, 5, and/or 6 for various Other Types of Pathologic Fractures. For these codes, the 6th Character is 8 for vertebral fractures. The M80 and M84 codes do require 7 characters to complete the code, with options of A, D, G, K, P, and S. The M81 Code Set is for Osteoporosis without current Pathologic Fracture and is the basic or primary code for Osteoporosis, which in and of itself does not cause pain. If there is low back pain in the presence of generalized osteoporosis and without a current pathologic fracture, then another cause for the pain needs to be identified and coded. Most often this would be associated arthritis of the spine. M83: Adult Osteomalacia (which literally means "softening of the bone”) would not in and of itself be a cause of Low Back Pain, and again some other cause for the pain would need to be identified. However, the softened bone might result in a pathologic fracture. As for Other Osteopathies (M86-M90) these do not really contain any useful codes for common causes for Low Back Pain except for Paget’s Disease of Bone (Osteitis Deformans), M88.1 for vertebral involvement, but not as a manifestation of a neoplastic disorder. If there is a neoplastic disease, Paget's Disease can be a manifestation, and the most correct code would be M90.68, but the neoplastic disorder also needs to be coded.

There is also the possibility of Low Back Pain resulting from the Code Set M96: Intra-operative and Post-procedural Complications and Disorders of the Musculoskeletal System. This has many possible diagnoses that could result in chronic low back pain as the lumbar spine is a common site of surgical intervention, particularly if that surgery involves the use of spinal implants and devices for stabilization. The code for a Failed Spinal Fusion/Arthrodesis which would be a Pseudoarthrosis is M96.0. Post-Laminectomy Syndrome (M96.3) would be for ongoing low back pain following a lumbar spine surgical procedure/laminectomy, i.e. a failed procedure. M96.69: Bone Fracture following insertion of Orthopedic Implant or Device could certainly occur in lumbar spine surgery resulting in persistent postoperative low back pain. M96.8 includes Intra-operative and Postoperative Complications and Disorders of the Musculoskeletal System, which includes Intra-operative bleeding disorders such as Hemorrhage or Hematoma from a spinal procedure. The code for this would be M96.810. There also could be Accidental Puncture or Laceration of a Musculoskeletal Structure during a Musculoskeletal Procedure, which would be code M96.820. For Post-procedural bleeding disorder (hemorrhage or hematoma) following a Musculoskeletal procedure the code would be M96.830. As of the 2017 coding updates and changes, Intra-operative and Post-procedural hemorrhage and hematoma have not been separated into separate codes for hemorrhage and for hematoma as has been done for these complications for Skin and Subcutaneous Procedures and for Neurosurgical procedures. (See the Coding Blog for 2017 Coding Changes and Updates)

The last of the Musculoskeletal categories is M99: Biomechanical lesions, not elsewhere classified (5th Character 2 for the TL spine, 3 for the L-spine, and 4 for the Sacral region). Most of these do apply to the spine (M99.1, 2, 3, 4, 5, 6, and 7) and could be causes for low back pain. However, these codes should not be used if the condition or cause of the pain can be identified more specifically elsewhere. This is a last resort code.

There are Congenital Malformations, Deformations (Q00-Q07) that can result in low back pain problems in older patients such as Q05: Spina Bifida with or without hydrocephalus; Q67: Congenital Musculoskeletal Deformities of the Spine (Q67.5: Congenital Scoliosis and Postural Scoliosis); Q76: Congenital Malformations of the Spine, including Spina Bifida Occulta (Q76.0) which as stated earlier is not a cause for low back pain; Q76.2: Congenital Spondylolysis and Spondylolisthesis; Q76.3: Congenital Scoliosis; and Q76.4: Other Congenital Malformations of the Spine not associated with scoliosis. As has been previously stated, these are not necessarily painful disorders during the growth and development of the patient, but when older and in adulthood, they could cause pain, particularly with degenerative processes occurring in the spine with aging.

Of the R Codes: General Symptoms and Signs (R50-R69) there is R52: Unspecified pain, which Includes acute pain and generalized pain, but Excludes Acute and Chronic Pain (G89) and Localized pain such as low back pain, with the coding directive to Code to Pain by Site. For practical purposes, this has no use for coding of low back pain problems.

For the G Codes: Diseases of the Nervous System (G00-G99), there are the Code Sets for Nerve, Nerve Root, and Plexus Disorders (G50-G59). These have little use in the coding of Low Back Pain with neurologic involvement (radiculopathy, radiculitis, etc.) since all of these codes Exclude identifiable spinal and/or disc disorders resulting in nerve and nerve root compression. The code(s) for the Spinal Disorder causing the neurologic dysfunction would have to be used. This goes back to the M Codes previously discussed. This leaves the code set of G89 for coding Pain (NEC). The useful codes from this set are not "stand alone” codes, but can be used as supplemental codes to the underlying disease code and Site of Pain Codes such as M54 for Low Back Pain. These would be “second listed” to the primary diagnosis, “first listed" code to help provide additional emphasis to the nature and severity of the patient’s pain. The exception to this is in the field of Pain Management where the purpose of the evaluation and treatment is for the treatment of the pain, not the underlying disorder causing the pain. In this case the G89 code would be "first listed," and supported or supplemented by the underlying diagnosis/disease code (“second listed”). The codes from this set that would be useful in coding for Low Back Pain are G89.1: Acute pain (NEC) including G89.11: Acute pain due to trauma (however, the injury to the lower back could not have an identifiable trauma or S code to explain the pain), and G89.18: Other Acute post-procedural or postoperative pain, i.e. more severe pain and would be expected from the procedure, and not explained by an identifiable surgical complication (T84 code). G89.2 codes are for Chronic Pain (NEC) with G89.21: Chronic pain due to trauma (with the same restrictions as for G89.11), and G89.28: Other chronic post-procedural and postoperative pain (again not related to an identifiable surgical complication (T84 code)). G89.3 is for for Neoplasm related pain, acute or chronic. This could be used to supplement back pain secondary to primary or metastatic neoplastic pain in the lower spine.

This is a long and extensive discourse on the coding of Low Back Pain, trying to cover as many relevant areas as possible out of the ICD-10 Codes. As stated at the beginning of this Blog, this is a very complicated region of the body with multiple bones, joints, muscles, ligaments, and tendons from which pain can arise. It has to be quite lengthy in order to provide sufficient education in detail for anyone who is involved with this area of coding. It is impossible to make it simple and straightforward.

Posted in Coding Blogs on Sep 19, 2016

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