What is Lumbosacral Discogenic Syndrome?
Low back pain is a frequent reason for disability amongst people, with hefty costs for the American healthcare system. Chronic low back pain can come from a variety of sources, which might be due to issues with the joints, muscles, spinal discs, fractures, or herniations. This explanation will concentrate on lumbosacral discogenic syndrome and pain from intervertebral disc disorders, which are problems related to the discs in your lower back.
Intervertebral discs are a type of cushion made from a special type of connective tissue called fibrocartilage, located between the bones of your spine. They make up about one third of your spinal column’s total height. These discs are primarily responsible for handling the weight of your body and muscle activity, and they assist in movements like bending and twisting of your spine.
Each disc is made up of two main parts: a central, jelly-like substance known as the nucleus pulposus and a tougher outer layer called the annulus fibrosis. The nucleus is kept together by a network of fibers known as collagen and elastin. These fibers, along with the substance’s water and proteoglycans (a type of protein), allow the nucleus to withstand compression. The annulus fibrosis comprises bundles of another type of collagen arranged in several layers of slanting bands, also known as lamellae. Healthy discs have a high water content in the nucleus and inner annulus. The outermost annulus withstands tension. A healthy disc is usually 7 to 10 mm thick and 4 cm in diameter in the lower back region.
The sinuvertebral nerve (SVN) offers nerve supply to the intervertebral discs and innervates (provides nerve supply to) the annulus and a ligament along the back of the spine. In healthy individuals, the nerve penetration into the annulus extends to about 3 mm, corresponding to the outer three layers of the lamellae.
The intervertebral discs have very little blood supply, with the nucleus and inner annulus depending on tiny blood vessels originating from the vertebral bodies. Only the outermost part of the annulus is supplied with blood. Due to this limited blood supply, it’s hard for intervertebral discs to recover from injury, and they often get worse over time as they cannot repair themselves effectively. This isn’t just because of lack of blood supply, but also due to a decrease in cell numbers.
Back pain may come from disc-related issues. However, not all damaged or worn-out discs cause pain. Disc abnormalities can often be seen on MRI scans in people who do not have symptoms. Given the other potential sources of lower back pain with similar symptoms, this poses a challenge to those providing treatment.
What Causes Lumbosacral Discogenic Syndrome?
As people age, the discs in their spine undergo natural changes. After young adulthood, there is a decrease in cell density in the nucleus of the disc (the center part of the disc). There is also an increase in older, non-functioning cells. This leads to a reduction in proteoglycan content (a type of protein), water content, and the regeneration of the extracellular matrix (a network of proteins and other molecules that surround cells). As a result, the outer ring of the disc, known as the annulus, becomes stiffer and has to bear more pressure.
Sometimes, the cartilage endplates, located on the top and bottom of each disc, can detach due to the loss of internal pressure in the disc. This can cause the nucleus to bulge into the body of the vertebra (the main part of the bone in the spine), leading to the annulus bulging out and the loss of disc height. This puts more stress on parts of the spine resulting in arthritis of the facet joints (where the vertebrae link together) and the formation of bony outgrowths known as osteophytes. These changes can cause back pain. Another aging-related change is the decrease in the ability of the vertebra endplates (the top and bottom surfaces of the vertebrae) to allow substances to pass through, which is different from disc degeneration where this ability actually increases due to damage.
Disc degeneration is defined as an abnormal, cell-driven response to ongoing structural failure, often accompanied by signs of early or severe aging. Causes of disc degeneration can include genetic factors, advanced age, poor transport of substances within the disc, and a history of heavy physical activities. These factors set the stage for normal daily activities to lead to structural failure in the disc.
Disc degeneration can lead to damage like fractures to the endplate, radial fissures (cracks spreading outwards), and herniation where the nucleus bulges out causing the disc to tear. This often occurs in the lower back due to its significant role in movement. Different types of tears can include circumferential (around the disc caused by shear stresses), peripheral (usually in the front part of the disc related to trauma), and radial (associated with breakdown of the nucleus and bulging at the back). If the nucleus bulges out significantly, this is referred to as a herniated or slipped disc, which can lead to disc material bulging out (protrusion), being squeezed out (extrusion), or being separated (sequestration). Additionally, damage to the endplate can cause an increase in substances that break down the disc and promote cell death (pro-apoptotic factors).
Risk Factors and Frequency for Lumbosacral Discogenic Syndrome
Lumbar intervertebral discs, the cushion-like parts of your lower back, can often lead to chronic back pain. In fact, about 26% to 42% of people with a condition called disc herniation, where the disc gets displaced or moves, experience this kind of pain. It’s hard, however, to find out how many people have disc degeneration because often it doesn’t cause any symptoms. A study found that when they did scans of people’s lower backs who didn’t have any pain, they found signs of disc degeneration in 37% of people who were only 20 years old! And as people got older, the chances increased. By the time people were 80 years old, almost all of them – 96% – had signs of disc degeneration. But, the study suggested that these changes might just be a normal part of aging, rather than something that always needs to be treated.
Signs and Symptoms of Lumbosacral Discogenic Syndrome
Discogenic pain, a type of back pain, usually affects the middle spine or the region close to the spine, sometimes extending to the sides or buttocks. Patients often feel this pain when they put weight on their spine, sit down, or bend their lower back. On the other hand, extending the lower back or lying flat on the back can help alleviate the pain. It’s also quite common to experience stiffness along with the pain. Due to the similar symptoms of other kinds of lower back pain, it can be challenging to diagnose discogenic pain correctly using a physical exam. Therefore, there are no specific physical tests that can definitively diagnose this condition.
Testing for Lumbosacral Discogenic Syndrome
If you’re experiencing ongoing low back pain, your doctor may want to give you a series of tests to better understand what’s causing the discomfort. This condition, known as discogenic pain, can sometimes be hard to tell apart from other causes of back pain; as such, imaging scans and certain procedures are often needed.
Throughout our lives, the discs in our spine can undergo wear and tear, a natural process known as disc degeneration. This can be seen in people who aren’t experiencing any discomfort, but usually becomes more common as we age. When looking at these imaging results, your doctor will always interpret these within the context of your symptoms.
Regular x-ray images can show that the space between your spinal discs has become narrower, a sign of disc degeneration. Other abnormal findings could include an accumulation of nitrogen gas known as a vacuum disc phenomenon, hardening of the end of the vertebrae (endplate sclerosis), and the formation of new bone (osteophytes). A CT scan, which provides more detailed images, might be able to detect these changes earlier in the disease process.
Magnetic resonance imaging (MRI) is typically the doctor’s preferred imaging method for disc degeneration because it provides exceptional detail of the soft tissues in the spine. One MRI finding related to disc degeneration, known as a High-Intensity Zone (HIZ), can indicate damage to the discs and potentially suggest a source of pain.
Besides HIZ, your MRI can show something called Modic changes – three different types of changes found in your spinal bones that relate to aging and disc degeneration. Type I Modic changes, visible as bright areas in your MRI, are strongly linked to disc degeneration and can cause pain.
If your doctor highly suspects that your pain might be coming from one of your spinal discs based on your symptoms and imaging results, they might propose a diagnostic procedure called provocative discography. Using x-ray guidance, your doctor will inject a contrast dye into the jelly-like center of the suspected painful disc. By putting pressure on the disc, the injection might replicate your pain symptoms, indicating the disc as the pain source.
This procedure isn’t without risks, though, and can potentially cause infection, tears in the protective covering of your spinal cord, leaks in your disc from too much dye, or even worsening of your disc degeneration. It can also be challenging to define the reliability of the procedure due to lack of gold standard comparison. Given these considerations, your doctor would only recommend this procedure if it would significantly affect your treatment plan.
Treatment Options for Lumbosacral Discogenic Syndrome
The first course of action for axial lower back pain is usually a conservative approach, involving physical therapy and exercises to perform at home. Different types of medication can also be used for reducing the pain, such as NSAIDs (Nonsteroidal anti-inflammatory drugs), like aspirin or ibuprofen. However, these should be used with caution over a longer period, as they can have effects on the digestive and urinary systems.
Opioids, a class of drug that includes morphine and codeine, are sometimes used in the treatment of chronic (long-term) back pain, but there is little evidence to suggest they are effective in these cases. Furthermore, the use of opioids can lead to increased sensitivity to pain, dependence, and risk of overdose. As a result, health organizations like the CDC recommends against their routine use for chronic low back pain.
If your back pain does not respond to these treatments, your healthcare provider might suggest interventional therapies. These are treatments designed to target the pain where it is coming from and include methods such as epidural steroid injections, needle procedures on the spinal disc, and heat treatments like intradiscal electrothermal therapy (IDET) and biacuplasty. Some of these treatments aim to reduce inflammation and pain by applying heat to destroy sensory nerves within the disc.
Other possibilities include injections of glucocorticoid (a type of steroid that can reduce inflammation) and stem cell solutions, which aim to repair and regenerate tissues. Platelet-rich plasma (PRP) therapy is another emerging option that uses a concentrate of your own blood to facilitate tissue repair and regeneration. Some early trials have shown this treatment can have pain relief effects, but more studies are needed to confirm.
Finally, if other treatments haven’t helped, your doctor may suggest surgical fusion, a procedure that joins two or more vertebrae into one solid bone, or artificial disc replacement. These surgical options aim to alleviate the pain while still preserving the natural movement of the spine. However, studies are currently still ongoing to verify the usefulness and safety of these procedures.
What else can Lumbosacral Discogenic Syndrome be?
Discogenic pain is a type of back pain that originates from the discs of the spine. However, there are other sources of back pain that can be a bit similar. Here’s a list of them:
- Joint disease in the backbone (facet arthropathy)
- Strain or minor injury in the muscles around the spine (paraspinal muscle sprain or strain)
- Strain or minor injury in the spine’s ligaments (ligament sprain or strain)
- Wear and tear in the spinal discs and joints (lumbar spondylosis)
- Stress fractures in the bones of the spine (lumbar spondylolysis)
- Slippage of one vertebral bone over another (lumbar spondylolisthesis)
Doctors use a combination of thorough medical history, detailed physical examination, and relevant imaging studies to differentiate between these conditions and make an accurate diagnosis.
What to expect with Lumbosacral Discogenic Syndrome
For patients who are disabled due to chronic low back pain for over six months, fewer than half of them likely return to their jobs. After two years, this likelihood reduces further. For people less than 45 years old in America, chronic low back pain is the most common reason for disability, regardless of what causes it.
Because of this, it’s crucial to start conservative treatments, such as physical therapy or lifestyle modifications, as soon as possible. With chronic low back pain, factors that can negatively affect recovery include emotional distress, ongoing legal issues, a tendency to feel physical symptoms related to psychological issues (somatization), and chronic smoking.
On the other hand, conditions that offer a better outlook include strong social support and symptoms that align with what is found in MRI results.
Possible Complications When Diagnosed with Lumbosacral Discogenic Syndrome
Disc-related pain can lead to serious problems, including physical disability and a negative impact on a patient’s mental health. Patients often experience heightened stress, depression, and anxiety following the onset of lower back pain. In cases where the spinal disc degeneration progresses rapidly, there may be a decrease in disc height. This can reduce the width of the spinal canal, leading to nerve root compression and radiculopathy which is pain radiating along the nerve due to the nerve irritation or inflammation.
The potential complications include:
- Significant disability
- Effects on psychological well-being
- Increased stress, depression, and anxiety
- Rapid degenerative disc disease
- Loss of disc height
- Decrease in the spinal canal diameter
- Compression of the nerve root
- Radiculopathy
Preventing Lumbosacral Discogenic Syndrome
A notable advantage of starting physical therapy soon includes teaching patients how to manage their symptoms and prevent them from getting worse. Patients have the opportunity to learn about different methods of putting a safe amount of pressure on their bodies, be educated on correct posture, start a walking regimen, and also experience lower back taping. A popular approach used in physical therapy for persistent lower back pain is the McKenzie method.
This method not only assesses your condition but also provides a specific treatment plan based around your preferred movements and comfort levels. Depending on what exactly is causing your pain, you will receive information about specific body positions and repeated movements that can help alleviate your pain and promote healing.