Degenerative Disc Disease
Updated: Nov 26, 2020
Degenerative disc disease in the lumbar spine, or lower back, refers to a syndrome in which age-related wear and tear on a spinal disc causes low back pain.
Intervertebral discs are tough, fibrous structures that act as ligaments between vertebrae, absorbing pressure and providing cushioning for the spinal column. Discs are flexible yet sturdy enough to facilitate movement such as bending forward, backward, and side to side.
Despite what the name suggests, degenerative disc disease is neither considered a true disease nor does it progressively worsen with time. Discs naturally stiffen with use and age, and everyone experiences some disc degeneration. Degenerative disc disease refers only to the condition of painful disc degeneration, and it is not uncommon for symptoms to alleviate as the spine gradually stabilizes.
Makeup of Intervertebral Discs
An intervertebral disc consists of three main parts:
Annulus fibrosis. The disc’s exterior is made up of concentric rings of collagen that twist and bend as the spine moves.
Nucleus pulposus. The disc’s interior is a gel-like mixture of water and proteins that provides cushioning between vertebral bodies.
Cartilaginous endplates. Between the disc and each vertebral body is an endplate made of cartilage that connects the disc to the vertebrae and acts as a gatekeeper, controlling the flow of oxygen and nutrients into the disc space.
A degenerated disc is marked by a significant decrease in hydration, making the disc inflexible, smaller, and more prone to tearing in the exterior. When one disc degenerates, it can alter the structure and mechanics of the lumbar spine, particularly at the segment surrounding the disc.
Lumbar Degenerative Disc Disease Symptoms
Most cases of lumbar degenerative disc disease consist of a low-grade, continuous but tolerable back pain that will occasionally intensify for a few days or more.
Symptoms can vary, but general characteristics usually include:
Moderate, continuous low back pain. Painful aches at the site of a damaged disc is the most common symptom of a degenerative disc. Pain may spread to the buttocks, groin, and upper thighs. This pain typically feels achy, dull, and can range from mild to severe.
Occasional pain flare-ups. Back pain may intensify for several days or weeks then return to a more moderate level. Flare-ups happen as the disc continues to degenerate and the spine gradually stabilizes. Pain flare-ups can be severe and sudden, and can temporarily reduce mobility.
Local tenderness. The area of the low back surrounding the degenerated disc may be sensitive to touch. Local soreness is caused by inflammation and muscle tension surrounding the degenerated disc.
Leg pain. Neurological symptoms including numbness, weakness, or sharp, shooting pains in the buttocks, hips, and/or back of the leg may be felt if the disc space collapses enough to pinch a nerve root exiting the spine. Leg pain from lumbar degenerative disc disease usually does not go below the knee.
Giving out symptoms. A feeling of sudden weakness or instability can happen as the disc becomes weaker, creating a sensation that the low back will “give out” with sudden movements.
Additionally, pain will typically feel better or worse with certain movements, positions, and postures, such as:
Pain with sitting. Sitting for prolonged periods often causes more severe low back pain and stiffness until standing up or changing positions. Sitting in a reclined, supported position is usually well tolerated.
Exacerbated pain with bending or twisting. Twisting the spine and forward, backward, and side-to-side bending can cause intense, concentrated pain around the disc.
Pain relief when walking or changing positions. When the spine changes positions, pressure is removed from the discs and placed on muscles and joints. Frequently changing positions, alternating between standing and sitting, or taking short walks can help alleviate stiffness and keep pain to a minimum.
Disc degeneration should not cause symptoms of bowel/bladder dysfunction, fever with back pain, unexplained and rapid weight loss, or intense stomach pain. These symptoms are suggestive of more serious conditions and should receive prompt medical attention.
In addition to low back pain from degenerative disc disease, other symptoms may occur that are caused by or related to the disc degeneration. For example:
The proteins in the disc space can cause significant inflammation if they come into contact with surrounding spinal structures, and this inflammation can lead to low back muscles spasms, as well as nerve root pain radiating to the hips and down the back of the legs (also called sciatica).
Lumbar disc degeneration can contribute to the development of lumbar stenosis and/or lumbar osteoarthritis, as well as other lower back conditions.
A degenerated disc may also lead to a lumbar herniated disc. Neurological symptoms are common when a disc herniates, including sciatica pain in the backs of the thighs that feels hot, sharp, or stinging.
Symptoms caused by a degenerated lumbar disc can vary widely, depending on how quickly or thoroughly the disc degenerates and how it affects the surrounding spinal structures.
Causes and Risk Factors of Lumbar Degenerative Disc Disease
Pain from degenerative disc disease is typically caused by strain on the muscles supporting the spine and inflammation around the disc space.
Degeneration occurs because of age-related wear-and-tear on a spinal disc, and may be accelerated by injury, health and lifestyle factors, and possibly by genetic predisposition to joint pain or musculoskeletal disorders. Degenerative disc disease rarely starts from a major trauma such as a car accident. It is most likely due to a low-energy injury to the disc.
Lumbar Degenerative Disc Disease Causes
The low back pain associated with lumbar degenerative disc disease is usually generated from one or both of following sources:
Inflammation, as the proteins in the disc space irritate the surrounding nerves—both the small nerve within the disc space and potentially the larger nerves that go to the legs (the sciatic nerve).
Abnormal micro-motion instability, when the outer rings of the disc, called the annulus fibrosis, are worn down and cannot absorb stress on the spine effectively, resulting in movement along the vertebral segment.
Over a long period of time the pain from lumbar degenerative disc disease eventually decreases, rather than becoming progressively worse. This pain relief occurs because a fully degenerated disc no longer has any inflammatory proteins (that can cause pain) and usually collapses into a stable position, eliminating the micro-motion that generates the pain.
The Degenerative Cascade
When a disc endplate is damaged, the blood supply to the discs is compromised, leading to a lack of nutrients and oxygen that are essential for restoring damaged tissues. Once one stress or injury occurs, a disc can begin to wear down relatively quickly in a process called the degenerative cascade.
The degenerative cascade is a slow process that typically continues for 10 to 30 years and usually consists of the following cycle:
An initial stress or injury may occur, causing acute pain that may be severe. Stiffness and limited mobility may occur immediately after the initial injury or stress to the disc. In many cases, there is no clear injury that causes the onset of symptoms.
The affected spinal segment then undergoes a long period of relative instability. As the disc height decreases, the muscles, ligaments, and facet joints around the disc space gradually adjust to stabilize the spine again. During this phase, there are periodic flare-ups of moderate or intense low back pain.
Once the spinal segment stabilizes, pain and other symptoms tend to alleviate.
It is common that back pain from degenerative disc disease is more severe between ages 30 and 40 than past age 60.
Risk Factors for Degenerative Disc Disease
Lifestyle factors that affect overall health can have an impact on the spinal discs. Risk factors for degenerative disc disease include:
Family history of back pain or musculoskeletal disorders
Excessive strain on the low back caused by sports, frequent heavy lifting, or labor-intensive jobs
Strain on the lumbar spinal discs due to prolonged sitting and/or poor posture
Lack of support for the discs due to weak core muscles
Smoking, or any form of nicotine intake
Disc degeneration is a common part of aging, but not all people develop pain or any remarkable symptoms. Symptoms tend to arise when spinal instability, muscle tension, and possibly nerve root irritation occurs.
Diagnosing Lumbar Degenerative Disc Disease
The first steps for a lumbar DDD diagnosis include the following:
A medical history is collected that details current symptoms, including when the pain began, if pain is accompanied by other symptoms such as numbness or tingling, and if pain started after an injury. A medical history also gathers information on regular physical activity, sleep habits, and past injuries.
A physical exam tests the spine’s range-of-motion and strength. A physical exam may include feeling by hand (called palpation) along the lower spine to locate areas of tenderness, inflammation, or physical abnormalities. Additionally, movement tests that determine which motions or positions alleviate or worsen pain can help indicate where pain is produced in the spine.
The above diagnostic methods are typically enough to diagnose pain from a spinal disc, and most cases can be diagnosed by visiting a primary care physician. Other cases may require insight from a spine specialist and/or additional testing. In order to locate the specific segment of disc degeneration, diagnostic imaging tests may be used.
Diagnostic Imaging for Degenerative Disc Disease
A definitive diagnosis for lumbar DDD may require an MRI scan to ensure that other issues are not contributing to pain, such as a fracture or disc herniation. If surgery is needed, an imaging test is required prior to the procedure to accurately locate the degenerated disc and plan the surgery.
An MRI (magnetic resonance imaging) scan uses a high-powered magnet to align and detect water molecules in the body, which allows doctors to visualize soft tissues such as muscles, ligaments and tendons, and spinal discs. MRI scans rely on magnetism rather than radiation—used in x-ray and CT scans—so there is little risk involved in an MRI scan, and scans are not painful.
MRI scans can provide useful information concerning:
Disc hydration (if there is little or no hydration, it may be referred to as a black disc, as the disc will appear black on the MRI scan)
Studies have shown that MRI findings of mild or significant disc degeneration are found on scans of patients with severe pain and minimal or no pain. Additionally, many painful conditions may not show up on an MRI, such as a tear in the disc’s outer rings or some cases of herniated discs. For this reason, a diagnosis cannot rely solely on imaging tests and must be used in combination with a medical history and physical examination.
Lumbar Degenerative Disc Disease Treatment
Treatment for painful degenerative disc disease focuses on minimizing pain, stabilizing the spine, and improving or maintaining mobility.
Degenerative disc disease can usually be treated with a combination of pain management techniques, physical therapy, surgery and other approaches.
Common Degenerative Disc Disease Treatments
Initial pain management methods for degenerative disc pain typically include a combination of the following:
Over-the-counter (OTC) pain medications. Aspirin, ibuprofen, or naproxen are common pain medications that can relieve inflammation that contributes to discomfort, stiffness, and nerve root irritation. Acetaminophen is a pain reliever that interferes with pain signals sent to the brain.
Prescription pain medications. Severe pain that is not relieved with OTC medications may be muscle relaxants or narcotic painkillers. These medications are commonly used to treat intense, acute pain that is not expected to last more than a few days or weeks. These medications can be addictive and cause serious side effects, so they must be used with caution and according to instructions provided by the prescribing doctor.
Heat and ice. Applying heat to the low back improves circulation, which reduces muscle spasms and tension and improves mobility. Ice packs can reduce inflammation and numb mild pain. It can be helpful to apply heat before physical activities to relax the muscles, and to apply ice after activity to minimize inflammation.
Massage therapy. Massage therapy can reduce tension and spasms in the low back muscles, reducing pressure on the spine and alleviating pain. Additionally, massage therapy can improve circulation, providing healing nutrients and oxygen to tense muscles.
Epidural steroid injections (ESIs). A steroid injection administered in the space surrounding the spine can reduce pain signals as well as inflammation. A steroid injection may be used in combination with a physical therapy program to provide pain relief during exercise and rehabilitation. When effective, an epidural steroid injection may alleviate pain for a couple weeks up to one year.
In many cases a combination of treatments is needed for effective pain management. A process of trial and error is typically necessary to find the treatments that best provide meaningful pain relief.
Prolonged bed rest is not recommended, and typically makes back pain worse. It may be helpful to rest for a day or so when pain is most severe, but staying inactive for prolonged periods can weaken the muscles and stiffen the spine, leading to increased pain.
Physical Therapy and Activity Modification
Physical therapy is often suggested or prescribed to help maintain healthy mobility in the spine. A thorough low back exercise program should include a combination of:
Exercise and Physical Therapy
Stretching exercises for muscles in the low back, hips, and pelvis, as well as the hamstring muscles. Tightness in these muscles places more pressure on the lumbar spine and contributes to low back pain.
Strengthening exercises that build lower back and abdominal muscles to maintain healthy postures and better support the spine. Strengthening exercise programs might include a customized physical therapy program, dynamic lumbar stabilization, tai chi, Pilates, or others.
Low-impact aerobic exercise that elevates the heart rate to improve circulation and deliver nutrients and oxygen necessary for healing the body’s tissues. Examples of aerobics that are gentle on the spine include walking, swimming and water aerobics, stationary biking, and running on an elliptical.
Physical therapy programs are usually tailored on a case-by-case basis according to overall health, severity of pain, and personal preferences.
Additionally, making small adjustments to everyday activities (lifestyle modifications) can effectively mitigate pain. For example, wearing a back brace while lifting, or avoiding twisting while lifting, can prevent pain from flaring up due to overuse. Using an ergonomic chair and supportive mattress can also provide daily relief.
Surgery for Lumbar Degenerative Disc Disease
Surgical treatment is an option in cases of severe, debilitating lumbar degenerative disc disease, and is usually recommended if the conservative treatment is not useful or if patient develops signs and symptoms of weakness in any or both the lower limbs, numbness or tingling, or loss of control of urinary or faecal sensation.
Lumbar Spinal Fusion Surgery
The standard surgical treatment for lumbar degenerative disc disease is a fusion surgery, in which two vertebrae are grafted together. The goal of fusion surgery is to reduce pain by eliminating motion at the spinal segment.
Fusion procedures can differ in how the spine is approached and the methods or tools used to fuse the joint. All spinal fusion surgeries consist of the following:
The affected spinal disc is entirely removed from the disc space (a discectomy).
The set-up for fusion is put in place, which may consist of a bone graft and/or instruments that further stabilize the spine, such as implants, plates, rods, and/or screws attached to the two vertebrae being fused.
The vertebrae then grow together, changing the joints to a solid, immobile structure.
Physical therapy, pain medication, and/or a back brace may be prescribed following surgery to manage pain and help strengthen the low back as the spine heals.
Artificial Disc Replacement Surgery
Artificial disc replacement has been developed in recent years as an alternative to spinal fusion. An artificial disc replacement surgery consists of removing the full spinal disc (a discectomy), returning the disc space to a natural height, and implanting an artificial disc device.
These devices are typically made of:
Two metal endplates that attach to the vertebral bodies and typically include a porous coating that encourages the bone to graft to the device.
A central core made of surgical-grade plastic (polyethylene) or metal (Titanium) that bends or turns to allow for movement at the spinal segment.
This procedure is intended to maintain movement in the spine similar to natural movements, reducing the chance of increased pressured placed on adjacent spinal segments.