Spinal Anatomy

The spine is composed of vertebral bodies, the bones. Between the vertebral bodies are the intervertebral discs. The facet joints are small joints in the back of the spine that help stabilize it by limiting our bending and twisting. The bony spine with the facet joints and discs protects the spinal cord and nerves traveling down. Small nerve roots come off the spinal cord.

How common is low back pain?

Low back pain is very common: it’s the second leading cause of a visit to a physician. Up to two-thirds of the population will experience low back pain at some point in their lives. About 5% of people experience back pain in a year, and 25% of people that experience back pain will end up seeing a doctor.

Most patients who come in with low back pain are between 30 and 50 years old. The peak incidence of herniated discs, discussed below, is 40-45 years old. The likelihood of back pain for obese patients is about twice as high as for non-obese patients. Having increased weight puts more pressure on the low back, but increased weight by itself is not a reason to have low back pain. Finally, cigarette smokers are more likely than non-smokers to experience low back pain.

Scientists have done many studies on physical fitness and low back pain. In a study on firefighters, the least physically fit firefighters had a nine-fold increase in low back pain compared to the most physically fit firefighters. In studies on core strength and low back pain, people who suffer with low back pain have lower core strength, or strength in the abdominal muscles and pelvic muscles that support the spine, than the people who don’t have low back pain. On the other hand, while it’s important to be strong, weightlifters are more likely to have back pain than the general population. Weightlifters have an incidence of low back pain at about 23% compared with about 5% for the general population, so not pushing too far and putting too much stress on your back is also important.

Diagnosing Low Back Pain

The history and physical exam are the most important parts of diagnosing a patient with low back pain. Typical questions include asking where the pain is, does the pain radiate, is there associated numbness or tingling, is there weakness in the legs, what’s the quality of the pain, and what helps relieve the pain (is it better sitting, standing, or walking). We also screen for red flags, such as fevers, chills, or patients experiencing a bowel or bladder incontinence.

When people have had pain for at least a few weeks, we’ll get x-rays taken. X-rays mainly show spinal alignment, and if there is any evidence of fractures or arthritis in the spine. X-rays don’t show soft tissues, so we cannot see if there is a pinched nerve, a spinal cord injury, disc herniation, or similar problem.

The next step would be to get an MRI scan of the low back to look at the soft tissues, to see disc herniations and pinched nerves. An MRI can also show a subtle fracture that doesn’t show up on x-rays, cancer of the spine or infections in the spine. Patients who cannot undergo an MRI, such as having a pacemaker or being extremely claustrophobic, may receive a CT scan instead. A CT scan doesn’t show quite as much detail as an MRI.

Overview of Common Back Injuries

Sprains and Strains

Sprains and strains include people throwing their back out or getting whiplash. These patients tend to be younger because they tend to be more active. This back pain is a sudden or acute onset of low back pain that’s worse with bending or lifting. The exact cause is not entirely clear. It may be a tear of the muscle fibers in the back or a tear of the disc resulting in muscle spasms.

An important note is that there are no neurologic signs associated with sprains and strains. In other words, people aren’t experiencing pain shooting down the legs with numbness, tingling and weakness. If imaging is performed, it’s generally normal.

Pinched Nerve

Pinched nerves in the low back are very common. The clinical term is radiculopathy; other common terms are herniated disc or sciatica. The disc is similar to a jelly donut. The center part, or the nucleus pulposus, is like a gel. The outer part, or the annulus, is a tough fibrous tissue to hold the nucleus pulposus in place.

As we get older, the discs get weaker. If you get a tear in the outer portion of the disc, the inner gel can leak out and pinch against the nerve.

People with pinched nerves in the back typically experience pain in the back, which often radiates into the buttocks and may go down into the toes. Numbness and tingling are very common, and weakness can happen as well. Usually sitting is uncomfortable, but depending on where the disc herniation is standing could be more uncomfortable.


Sacroiliitis is inflammation of the sacroiliac joints, which are formed where the pelvis meets the tailbone. Falls onto the buttocks can irritate that joint and cause sacroiliitis, or arthritis may develop in these joints. The pain is primarily in the buttock, but it can radiate around the front to the groin or go down the thigh. Typically patients will not have neurologic symptoms (numbness, tingling or weakness).

Facet Joint Arthritis

The facet joints in the back of the spine can get arthritis. Arthritis is inflammation of a joint and as the inflammation gets worse the cartilage in the joint starts to degrade or wear down. When the cartilage is gone the bones rub against each other, which is painful. Facet joint arthritis typically causes pain through the low back that generally does not radiate down the legs. There’s no numbness or tingling with it, but it’s usually worse when we stand or bend or twist just because those movements put more pressure on the joints.

Degenerative Disc Disease

Degenerative disc disease is degeneration of the spine that occurs with microtrauma. Years of hard work causes wear and tear and wear the disc down so the bones are touching. There’s likely a genetic component, as people frequently recognize that their parents had the condition. Usually the lower discs in the spine are affected because most of our body weight is placed on those discs.

Spinal Stenosis

Spinal stenosis is similar to disc herniation, but in spinal stenosis the canal in the spine where the nerves come through becomes tight for a multitude of reasons. The disc could be bulging back, or the facet joints may become calcified and grow larger as they become arthritic. Regardless of the reason, you get crowding of the canal where the spinal cord and nerves come through.

In spinal stenosis, people tend to get low back and buttock pain, including pain shooting down the legs and numbness and tingling similar to a disc herniation. With spinal stenosis, symptoms are usually worse with standing or walking. A common complaint is that a patient must stop and take a break halfway through a grocery trip: their legs get numb and tingling and pain is shooting down the legs. After a short break, they are able to walk again for another few minutes.

Non-Surgical Treatments


If someone hurt their back a few hours ago up to a day or two ago, rest is the first treatment. We’re trying to get the inflammation to calm down. However, we don’t recommend bed rest for more than a day or two; people become weaker on bed rest so it is counterproductive.

Physical Therapy

Physical therapy will often start early. Core muscles are very important to help stabilize the spine, so strengthening the core muscles can take the pressure off of the discs, nerves and joints. Chiropractic care is helpful in some situations as well.


Medications may be used, including topical medications like Voltaren gel, an over-the-counter anti-inflammatory. Lidocaine patches include a numbing medication to help relieve some pain. Oral anti-inflammatories, or NSAIDs, like ibuprofen, Aleve or meloxicam, may be tried. Sometimes oral corticosteroids like prednisone, a stronger anti-inflammatory medication, are used. Muscle relaxants are also used, which tend to cause drowsiness or grogginess so aren’t the best for everyone. Finally, medications for nerve pain may be used, like gabapentin or Lyrica.


If people have tried resting, anti-inflammatory medications and therapy and nothing seems to be helping, we may try spinal injections. These injections are done under x-rays so we can accurately target where we want the medication to go by the pain generator. Typically we’ll inject a little bit of dye under the x-rays to confirm that the flow of medication is going in the correct place.

Typically the injections are corticosteroids, or a type of prednisone that we’re injecting. Once we can get the inflammation calmed down with steroids, the pain typically improves.

Steroid injections may be repeated if the symptoms return. Around 60% to 70% of patients achieve significant benefit from the injections.

Radiofrequency Ablation

Radiofrequency ablation or radiofrequency neurotomy is a procedure where the doctor cauterizes or burns the small nerves that go to the facet joints. The idea is that blocking the pain signals from those joints helps relieve the arthritis pain.

The process has several steps. Under x-ray, we numb the tiny nerves to see if it relieves the pain. This process serves as a diagnostic test. If it works to relieve the pain, insurance regulations generally require that we try it again two weeks later to confirm that the patient still receives relief. Then the procedure is approved, and the nerves may be burned. To burn them, a special needle is used under x-ray. The tip of the needle can heat up and create a very small burn on the tiny nerve.

These nerves tend to regrow after about a year, so the procedure may be repeated.

Sometimes patients will ask about burning the nerves that go down the legs to provide pain relief from pain in the legs. However, we can only burn the tiny nerves in the facet joints. Burning the larger nerves that go down the legs would paralyze the patient.

Frequently asked questions

What is the difference between a herniated disc and a bulging disc? Will a herniated disc heal?

There are different classifications of disc bulges. A disc bulge is generally milder than a protrusion which is milder than a disc herniation, although I tend to use the terms interchangeably.

In some situations, your body can absorb the gel that protrudes out and heal. However, in most situations, the bulges don’t go away. When the disc bulges out or herniates, the nerve will get irritated. Once the nerve settles down, typically it will do well even though the disc bulge is still there.

How do you prevent being bent forward as you get older?

In many cases, people stand in that way because of arthritis in their backs. The forward posture tends to provide some relieve, so people maintain that posture because it is more comfortable. In other cases, people have had compression fractures in their back that bend them forward, so the reasons can vary case-by-case. Keeping your back as strong as possible and doing those core strengthening exercises is the best way to prevent it.

If there’s numbness without pain, is that a risk for anything in the future? Should it be treated?

When a nerve is irritated, you may get pain, numbness, tingling, or weakness. Some people get numbness by itself. Generally, I wouldn’t consider it to be anything to be tremendously concerned about for a few weeks. If it persists, I would get it checked out to confirm there is nothing more serious going on. Long term, there are some people who have had a disc herniation who have chronic numbness. It may be annoying but it doesn’t bother them too much and it is acceptable to live with.

Is low back pain the same on both sides of your body?

It depends on what is happening with the spine. These conditions may affect one side of the spine or both sides of the spine.

Do you recommend heat or ice for low back pain?

Generally, within the first 48 hours of an injury, we tell people to ice and the idea behind that is to help reduce inflammation. Beyond that, the studies are not really clear. Generally, what I tell folks is beyond 48 hours I would do whatever feels better. Some folks do well with ice, some folks do well with heat and some people alternate and get benefit.