What is Bulging Disc?
Written by Neil Badlani, M.D., Chief Medical Officer, North American Spine

In its most basic definition, a bulging or herniated disc occurs when an intervertebral disc, which serves as a cushion between the vertebrae, loses its typical shape and compresses a spinal nerve. To understand what a bulging or herniated disc is, we first need to understand the basic structure of an intervertebral disc.

An intervertebral disc has two main parts: an outer shell of fibrous cartilage (the annulus fibrosis) and an inner filling of a jelly-like material (the nucleus pulposus). The outer wall of an intervertebral disc can become weakened for a variety of reasons. As people age, the fibrous material becomes more brittle. Excessive strain can rupture the annulus fibrosis. Poor diet and exercise habits can also weaken the disc.

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More About Bulging Disc

lumbar foraminotomyRegardless of the cause, once the tough shell of the disc is weakened or cracked, the soft gel of the nucleus pulposus can deform the disc. Once deformation occurs, the disc may irritate or pinch one or more spinal nerves, causing pain.

Though the two terms are often used interchangeably, there is a subtle difference between a “herniated” disc and a “bulging” disc. On one hand, a herniated disc is a condition in which the tough outer wall of an intervertebral disc has been weakened, allowing the softer insides to deform the shape of the disc. In some cases, a herniated disc will press against the spinal nerves, causing pain. A bulging disc, on the other hand, results when an intervertebral disc, which serves as a cushion between the vertebrae, loses its typical shape and compresses a spinal nerve.

Bulging discs (also called “protruding discs”) have undergone changes in their shape and structural integrity that can lead to spine pain or other problems. Unlike herniated discs, bulging discs have not broken through their outer shell-like casing. Sometimes, a bulging disc and a bone spur occur at the same time. This condition is known as disc osteophyte complex.

If your lower back is hurting, there is a good chance that a bulging or herniated disc may be the cause. Although any one of the intervertebral discs in your spinal column can become damaged, herniated discs are more common in the lumbar region of the spine. This is because the lumbar region supports more weight than other parts of the back. When excess weight is put on this area, there is an increased risk of rupturing a disc.

Whether it’s a herniated or bulging disc, both conditions are easily treated using the same minimally invasive methods. And these methods, whether non-surgical, decompression, or fusion, are certain to have you living a pain free life in a matter of days.

What are the symptoms?

In most cases, bulging discs appear at the rear and side portions of the affected disc, and can put abnormal pressure on the nerve below the disc, causing a range of pain types. In severe cases, you may experience heaviness in your legs and/or difficulty walking. 

Common symptoms of Bulging Disc include:

  • In the lumbar spine: pain, numbness, tingling, burning, and weakness in the lower back, buttocks, legs, and feet
  • In the cervical spine: pain, numbness, tingling, burning, and weakness in the neck, arms, hands, and sometimes in the head
  • In the thoracic spine (less common): pain in the upper back, radiating through the stomach or chest, which patients often confuse for cardiovascular problems

How is a Bulging Disc Diagnosed?

Pain is the first indicator of a bulging disc that needs attention. Once identified, there are typically four steps to the process

•  Physical Examination:

This involves the doctor assessing things like levels of pain in response to specific motions or palpation (physical touch). It may also include testing flinching reactions in arms or legs, and assessment for atrophied muscles.

•  Symptom Assessment:

The doctor needs to know as much as possible about the symptoms the patient is experiencing. This involves answering a series of questions to give a sense of whether pain is dull or sharp, as well as where and when it’s likely to occur.

•  Medical History:

As with any kind of disease or condition, diagnosis also needs to take into account the patient’s full medical history. This allows the doctor to figure out if other conditions are causing the pain, and they’ll learn about previous diagnoses, any drugs taken, previous surgeries and other important pieces of information.

•  Diagnostic Imaging:

Though often believed to be diagnosis in itself, medical imaging like X-rays or MRI scans are actually only meant to confirm that there’s a problem. This also lets the doctor see more exactly where the issue is taking place.

Interestingly enough, there are many cases where disc problems don’t actually cause pain; an MRI, in itself, is not enough to serve as diagnosis. It’s only when the physical exam and symptoms match up with the imaging results that a diagnosis can truly be established.

What are the causes of a bulging disc?

low back pain

Bulging discs occur when pressure on a spinal disc damages or breaks down the once healthy disc, causing it to compress or change its normal shape. This can in turn put pressure on spinal nerves, causing pain and inflammation. Potential causes of this pressure include:

  • Age-related wear and tear, which can lead to Degenerative Disc Disease
  • Back or neck strain due to repetitive physical activity, poor posture, imbalances in the musculature, or heavy lifting
  • Direct physical injury such as a car accident or fall
  • Genetics, whether or not the symptoms appeared in your parents

How are Bulging Discs treated?

Treatment and procedure options for Bulging Disc range from conservative options like injections to more intensive procedures like spinal fusions.

Conservative Options

Conservative treatment options include nerve root blocks and steroid injections. These are designed to provide temporary relief (up to one year), and you may elect to have the procedure done multiple times. Other conservative strategies may include the placement of a spinal cord stimulator–or STIM–which is designed not to correct the underlying degeneration, but to lessen the pain the condition causes.


Minimally invasive decompression surgery aims to relieve pressure on the nerves of the spine. This pressure is often caused by stenosis, bulging or herniated discs, and more. Relieving this pressure can be achieved by reducing or removing soft tissue (disc material or scar tissue) or bone (bone spurs, a section of the lamina or foramina) to decompress the affected nerve. When the compression is caused by soft tissue material, a surgical laser may be used to shrink the impinging material.


Fusion surgeries are similar in goal–to remove damaged disc tissue and fuse the bones together–but differ in approach, including the use of specialized hardware to reinforce stability, and the location used to gain access to the spine. A related procedure is an artificial disc replacement, in which a damaged cervical disc is replaced with a synthetic disc, and the vertebrae are not fused.

How Much Does Treatment Cost?

Treatment cost depends on several factors, especially what insurance you have and how much of your deductible has been met. IN the last two years, 90% of our patients have paid less than $2000 out-of-pocket. Some have paid literally nothing, and other have paid much more than that. It depends. The good news is: our Patient Care Managers will handle as much as they can directly with your insurance company, and all your costs will be known up-front.

Important note: spine surgery often pays for itself within a year or two. Many people actually spend more money trying to live with the pain than they do getting the pain fixed. The following calculator is intended to give you a sense of what you spend on managing—rather than eradicating—your pain.


Calculate how much you've spent on back pain this year.


This past year you have spent on your pain treatment:

Get surgery now. Getting surgery now is the smartest financial move. Over the last two years, the average North American Spine patient spent around $2,000 out-of-pocket for treatment. You’ve spent that much or more this year to manage your back pain than you could to fix it.

Get surgery soon. Over the last two years, the average North American Spine patient spent around $2,000 out-of-pocket for treatment. At your current rate, you will spend that much or more within the next two years. The sooner you get treatment, the sooner it will pay for itself.

Keep an eye on your spending. Currently, you are managing your pain efficiently from a financial perspective but over time, your expenses could add up. Surgery should be strongly considered if you start missing more work or spending more on treatment medication.

Great job! You are spending very little on your back pain. Keep it up!

Equipment Used in Diagnosis and Treatment of a Bulging Disc

In an IntelliSpine procedure, your physician will access your spine with a small, hollow needle using a live x-ray for guidance. A discogram will confirm the herniation visually, showing the extent of degeneration as well as the presence of tears. A laser will then be guided through the needle to shrink the bulging/herniated disc material or scar tissue impinging on a spinal nerve.

Very small incisions are made, and recovery time is very quick compared to traditional, open surgery.


How Does Bulging Disc Compare to Other Spine Conditions?

Different people refer to bulging discs in different ways. For example, some call a bulging disc a “a disc protrusion”, others call it a “herniated disc.” Here is a list of terms that may refer to a bulging disc or a closely related condition:

  • Collapsed Disc
  • Herniated Disc
  • Herniated Nucleus Pulposus (HNP)
  • Slipped Disc
  • Disc Extrusion
  • Disc Protrusion
  • Pinched Nerve
  • Compressed Nerve

While some of these terms are interchangeable, some are not. In general, all of these terms refer to stages in the process of disc herniation. A disc is a kind of shock absorber located between vertebral segments. It is encased by a protective sac. When the disc loses its shape, herniation results. When this herniation stays within its sac, it is often called a “Bulging” or “Collapsed Disc.” When the disc actually breaks through its sac, it is called a “slipped,” “torn,” or “extruded” disc.

So, a bulging disc is a less severe form of herniation than a torn—or extruded—disc, but all forms of herniation have the potential to cause significant pain. This is because the herniated disc material may “impinge upon,” “compress,” or “pinch” a nerve.

Finally, most disc herniations are the result of an underlying process of deterioration called “Degenerative Disc Disease,” “Degenerative Spine Disease,” or “Arthritis of the Spine.”

So recap: Degenerative Disc Disease is usually an underlying cause of bulging discs (which are sometimes called by another name), which in turn cause the painful phenomenon of a pinched (or compressed, or impinged) nerve.

Analogy: Blow-Out vs Flat Tire

A bulging disc is like a flat tire, a slipped disc is like a blowout. When you have a flat tire, the wheel’s material loses its shape, but it stays more or less together. In a blowout, the inside of the wheel becomes exposed to the outside.

Both conditions can cause pain, and both should be professionally evaluated. And don’t forget: a bulging disc (flat tire) can progress to become a slipped disc (blowout).


Blow-Out = Instant Rupture

Flat Tire

Flat Tire = Slow Leak

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