At least 80% of people in the U.S. will experience an episode of low back pain at least once in their lives. Approximately 15% of these episodes will progress to chronic back pain.
Books and volumes have been written about low back pain, and a complete discussion is beyond the scope of this site. But we would like to present you with some facts and ideas that you may not hear anywhere else.
Low Back Stability, Structures & Pain
The low back gets its stability from several structures—the bones and joints, the intervertebral discs, the ligaments, and the muscles.
The Bone & Joints
The bones and joints form the building blocks of the spine. The joints of the low back are called the facet joints. They are the small joints located on the back of the spinal column. Compression fractures of the vertebral bodies, arthritis of the facet joints, surgery that removes facet joints (such as a laminectomy), and fractures or congenital abnormalities of the portion of bone between the facet joints (called the “pars interarticularis”), causing a “spondylolysis,” all can disrupt the stability of the bony spine.
Under normal conditions in the healthy spine, the facet joints bear about 25% of the axial load the spine, and the discs bear the remaining 75%. When the discs start to wear out, more of the load is shifted to the facet joints, which causes premature wear, arthritis, and subsequent instability and pain. Arthritic change in the facet joints is known as degenerative joint disease.
The discs act as shock absorbers between the vertebrae. The disc is a fluid-filled structure, with a thick fibrous outer ring, called the annulus, surrounding a gelatin-like center, called the nucleus pulposis. The discs are firmly attached to the vertebrae above and below. There is therefore no such thing as a “slipped disc.”
Like a water balloon when you squeeze it, discs bulge under pressure or load. They’re supposed to do this! This is how they help cushion the bones. In other words, disc bulging is normal. Problems occur when they bulge too much, thereby stretching the outer fibrous ring and irritating the attached nerves.
Over time, the fluid inside the discs begins to diminish, and the disc undergoes “degeneration,” a type of wear and tear. Again this is normal. However, sometimes excessive physical or sports activities, injuries to the disc, and genetic factors can cause a disc to wear out prematurely. This is known as degenerative disc disease.
It is used to be thought that degenerative discs did not cause pain. But recent research is questioning this, and some researchers believe that as the disc breaks down, occasionally it leaks out inflammatory chemicals that irritate surrounding nerves and ligaments.
A herniated disc occurs when a tear develops in the outer ring (the annulus), allowing some of the gelatin-like nucleus to squirt out. This puts pressure on the nerve exiting the spine and causes symptoms of sciatica.
MRI Evaluation of Disc Problems
Patients often ask that an MRI be performed to look for disc problems. The problem is that not all disc cause pain. A study published in 1994 in the new England Journal of Medicine, performed MRIs on almost 100 people with no history of back pain (Jensen et al. N Engl J Med. 1994;331:115-116). 64% of these “normal” people had at least one abnormal disc—52% had bulging discs, 27% had disc protrusion, and 1% had a frankly herniated disc. 38% of the subjects had more than one abnormal disc. But none of them had any pain! MRIs and CT scans can show disc abnormalities, but they cannot tell whether a disc is causing pain.
Low Back Ligaments
Ligaments connect bone to bone. They hold the joints together. They are the “guy wires” that limit and control motion. They also have a strong nerve supply, which is why it hurts so much when you sprain something. Damage to a ligament is called a sprain.
The ligaments of the low back help stabilize the low back joints. The ligaments are damaged in several ways. Lifting an item improperly, bending and twisting (such as shoveling snow or reaching into the trunk of your car), childbirth, or repetitive strain over time all can injure them. When a ligament is damaged, spine stability can become compromised, occasionally leading to slightly increased motion in the joints.
Sprains can range from mild overstretching to complete tearing of the whole ligament. In the low back, complete tearing almost never occurs. More commonly, overstretching or small tears cause the pain. Ligament injuries in the low back can cause pain in many ways. The ligament itself can cause pain over the injured area or it can refer pain to another location. They can cause the muscles of the low back to tighten up, both because of the pain and because the muscle is trying to stabilize the spine in the face of a loosened ligament. Ligament injuries also can cause pain due to the increased motion in the joints, as noted above, resulting in additional wear on the joints and discs.
The pictures below show the referred pain patterns (the stippled areas) from the key low back ligaments.
The muscles of the low back are critical for support, stability, and movement. In fact, a human spine with all of the muscles stripped away (leaving only the ligaments) will collapse under only 5 pounds of force! Strong muscles help take stress off the discs, joints and ligaments. In addition, strong muscles provide the endurance to perform physically demanding tasks throughout the day. Think of the muscles as the “shock absorbers” of the spine.
The muscles of the low back work in close conjunction with the muscles of the buttocks and legs to provide stability for the low back. This coordinated muscle activation is so closely intertwined that, when one muscle is not working properly, other muscles will begin to work harder to compensate for it, leading to pain.
In addition, muscles can also react to damage to the discs, joints and ligaments by tightening up. Think of it as the body’s attempt to protect and stabilize itself. This can cause chronic muscle tightness. It also can cause trigger points to form in the muscles.
Trigger points are small focal areas of muscle irritability. The pain from trigger points can be either local or it can refer to other areas. It can be steady or intermittent, dull and aching, often deep. It may occur at rest, or only with movement. It varies from being a low-grade discomfort to severe and incapacitating. Also, the pain from trigger points can mimic other causes of pain, occasionally leading to wrong diagnoses and unnecessary treatment.
The brain is actually the most important “pain” structure. It is our brain that interprets the various nerve signals as “pain” and then tells us how to react or respond to them. Dr. Tortland recalls one patient who had chronic back pain that failed to respond to all treatments—physical therapy, manipulation, injections, medication—and she was discharged. Several months later Dr. Tortland met her in the grocery store, and she told him her back pain completely disappeared one week after she quit her job!
While not all back pain is due to stress, stress and psychological factors certainly can play a role in back pain.
In addition, as noted above the brain and central nervous system can become sensitized in the face of chronic pain, resulting in persistent pain processing, even long after the original injury heals.
Diagnosing Low Back Pain
First, no matter what someone tells you, there is no test available to diagnose “pain” per se. X-rays, MRI’s, CT scans, bone scans, etc. look at structures, but they cannot tell whether those structures are causing pain, even if the structures are abnormal. As noted above, over half of normal people with no back pain will have abnormal discs on an MRI scan.
Does that mean it’s worthless to perform these studies? Absolutely not. At the very least, these studies can help tell us what is NOT causing the pain, and they can help pinpoint possible causes of pain. But it is an inexact science at best, the test results need to be considered in the context of the clinical picture (symptoms, physical exam, etc.).
Also, not every study needs to be done to make a diagnosis. Not every case of low back pain requires an MRI or even an x-ray. The experience and clinical judgment of the physician should dictate whether a study will aid in the diagnosis and treatment.
History and Physical Exam
The single greatest tool in diagnosing LBP is the History and Physical Exam. How/when the pain started, where the pain is located and refers to, what makes it better/worse, what treatments have been attempted—all these are important to help understand potential causes of LBP. In many cases, a thorough history alone can point to a probable cause.
The Physical Exam of course gives the doctor an opportunity to look for signs that may help indicate the source of the pain. An exam should be more than simply having you bend forward and checking your reflexes! If a doctor does not physically examine you—feel for tenderness, muscle spasm, trigger points, restricted range of motion, muscle firing patterns, etc.—it simply is an incomplete exam.
Special tests can be performed to help determine the cause of pain. These can be as simple as certain tests of movement done in the office, to a novocaine injection to numb a suspected cause of pain, to tests that have to be done in a special facility.
For example, to help determine whether a disc is causing pain, sometimes a discogram is done. Under x-ray guidance, fluid is injected directly into the suspected disc in an effort to reproduce the patient’s symptoms. If the identical symptoms develop, then the disc is likely the source of the pain.
Your doctor will advise you as to what additional tests he/she thinks are appropriate.
Treating Low Back Pain
Entire texts have been written about treating LBP, but the following is an overview, including the approaches we use here at Valley Sports Physicians.
There is no medication that exists that will completely eliminate pain. Period. The goal of medication is reduce pain to a level that enables you to perform the tasks of work and daily activities with the least amount of intrusion.
Medications that are commonly used to treat pain include anti-inflammatory medications, such as ibuprofen (Advil®, Motrin®), naproxen (Aleve®), and Celebrex; Tylenol; various narcotic preparations, including hydrocodone, oxycodone, morphine, methadone; and narcotic-like medications, such as tramadol (Ultram®, Ultracet®).
Medications that are not specifically pain medications but that are very useful in treating chronic pain include various anti-depressants, including Cymbalta® and Lexapro®; anti-seizure medications such as gabapentin (Neurontin®) and pregabalin (Lyrica®); and central nervous system medications such as Gabitril®.
Muscle relaxers also are commonly used, typically in combination with other medications.
Most often a combination of two or more different types of medications is used in order to take advantage of the different mechanisms of action. In addition, occasionally several different medications may be tried in order to find the one(s) that best help treat the pain.
However, medication by itself is rarely the sole answer to treating pain. Medication most often is used to help reduce the pain so you can pursue the other treatments, such as exercise and physical therapy.
In chronic low back pain, the goal of physical therapy more appropriately is to improve function. In chronic pain, whether as a result of the original injury or as a result of muscular compensation, most people develop altered movement and muscle firing patterns. Some muscles become weak or inhibited, while other muscles become tight or over-activated. These altered muscle firing patterns lead to changes in motor control, which then helps perpetuate the chronic pain.
Physical therapy procedures such as hot packs, cold packs, ultrasound, and electrical stimulation may help you feel better in the very short term, but they do nothing to address the altered motor control problems. Furthermore, most physical therapy stretches and exercises likewise not only most often do not address the motor control issues, but more often just reinforce the underlying muscle firing dysfunction. This is one of the reasons why many physical therapy programs either do not help—or even sometimes aggravate—chronic back pain conditions.
There are two other problems with most traditional physical approaches to treating chronic pain. First, most therapy clinics do not allow enough one-on-one time between the patient and therapist. Many therapy clinics have the therapist treating more than one patient at a time in order to maximize revenue. Treating chronic pain requires at least 30 minutes, and preferably 45-50 minutes, of dedicated one-on-one time. Second, physical therapy for treating chronic back pain is best performed once every 1-3 weeks over a several month period, not 2-3 times a week for just a few weeks.
Most physical therapists, while well-meaning and sincere in their desire to help patients, are not properly trained in the rehabilitation techniques to identify and address the underlying neuromuscular firing abnormalities. At Valley Sports Physicians, we regularly send our therapists to special training courses, taught by internationally-recognized rehabilitation experts in chronic pain and motor control. Please see our section on Physical Therapy.
Manual treatment, such as Osteopathic Manipulative Treatment or chiropractic treatment, can be a useful treatment as well. Rarely does this type of treatment cure chronic back pain. However, it can help improve and maintain mobility and help the other treatment approaches work more effectively. Be careful, though—manipulation treatments that are too frequent can actually worsen your condition by creating further instability. In our opinion, there really is no indication for manipulation treatment multiple times a week, and usually not more than one or a few times a month.
There are a number of injection therapies that may be tried for the treatment of chronic LBP.
Trigger Point Injections
As noted above, trigger points are small focal regions of muscle irritability that can cause local and referred pain. In addition, trigger points prevent the muscle from being stretched fully. When you try to stretch a muscle that has a trigger point in it, the stretching activates the trigger point, causing the muscle reflexively to tighten up. Trigger points are treated by injecting them with novocaine, then almost immediately, while the trigger point is still numb, stretching the muscle. Numbing the trigger temporarily inactivates it so you can then stretch the muscle more fully. If you do not stretch the muscle after doing the injection, you have almost wasted the injection. Many times trigger points need to be treated multiple times in order to “break” the cycle or pattern. If the triggers continue to return, however, then there is usually something else going on that is causing the triggers to form.
Epidural Steroid Injections
The epidural space is the space between the dura mater (a membrane covering the brain and spinal cord) and the wall of the vertebral column. It is filled with fat and small blood vessels. It is located just outside the dural sac. The dural sac surrounds the nerve roots and cerebrospinal fluid (the fluid that the nerve roots are bathed in).
An “epidural” is an injection that delivers steroid medication directly into the epidural space in the spine. Sometimes a flushing solution (either lidocaine or normal saline) is also used to help “flush out” inflammatory proteins from around the area that may be the source of pain.
There are often inflammatory factors and other substances that generate pain that are associated with a lumbar disc herniation, and this inflammation can cause significant nerve root irritation and swelling.
Steroids (corticosteroids) have been shown to reduce inflammation by inhibiting the production of substances that cause inflammation. The epidural steroid injection can be highly effective because it delivers the medication directly to the site of inflammation.
Epidural injections can be used diagnostically as well as therapeutically. If the diagnosis or cause of the pain is unclear, particularly if there is a question about whether a disc is causing the pain, an epidural can be done. If there is significant pain relief, then it is more likely that the disc or disc-related structures are causing the pain, and further treatment can be directed accordingly.
Epidural injections are performed under special x-ray guidance by physicians properly trained in the procedure.
Facet Nerve Blocks
The facet joint is the small bony joint on either side of the vertebrae. Like all joints in the body, there is a nerve that innervates the joint. As noted above, the facet joint can be sprained or undergo arthritic change and cause pain. The nerve that innervates the facet joint can be numbed temporarily to see if there is pain relief. Like epidural injections, this is done under x-ray guidance.
Prolotherapy is a special injection procedure designed to repair damaged ligaments and tendons. Many times, low back pain is due to ligament and tendon injuries (sprains & strains). If physical therapy and other conservative treatments don’t help, prolotherapy may be indicated. A more thorough discussion on Prolotherapy is contained elsewhere on this web site.
Surgery may be indicated for certain herniated discs or disc-related problems. However, most studies indicate that over 90% of herniated disc do not require surgery. Fairly recent technological advances have made disc replacement surgery a reality for many patients, and a spine surgeon can advise you as to whether you may be a candidate for this. However, except for a few rare circumstances, surgery is almost always a last resort.
Many alternative therapies may be useful as part of a comprehensive treatment plan for chronic LBP. These can include:
- Massage therapy
- Yoga or TaiChi
- Therapeutic Touch
Ask your doctor about the appropriateness of these for your particular condition.