Non-specific low back pain or lumbago (pron.: /lʌmˈbeɪɡoʊ/) is a common musculoskeletal disorder affecting 80% of people at some point in their lives. In the United States it is the most common cause of job-related disability, a leading contributor to missed work, and the second most common neurological ailment — only headache is more common. It can be either acute, subacute or chronic in duration. With conservative measures, the symptoms of low back pain typically show significant improvement within a few weeks from onset.
Lower back pain may be classified by the duration of symptoms as acute, subacute and chronic. Within these classifications, there is no agreement across medical organizations for the specific duration of symptoms, but generally pain lasting less than six weeks is classified as acute, pain lasting six to 12 weeks is subacute, and more than 12 weeks is chronic.
The majority of lower back pain is referred to as non specific low back pain and does not have a definitive cause. It is believed to stem from benign musculoskeletal problems such as muscle or soft tissues sprain or strains. This is particularly true when the pain arose suddenly during physical loading of the back, with the pain lateral to the spine. The full differential diagnosis includes many other less common conditions.
Pain sensation and perception
In general, pain is an unpleasant feeling in response to stimuli that have the potential to damage the body's tissues (noxious stimuli). There are four fundamental steps in the process of pain perception: transduction, transmission, perception and modulation. The process starts when the painful event stimulates the endings of the pain-sensing nerve cells (nociceptors). A nociceptor converts the stimulus into an electrical signal by transduction. Several different types of nerve fibers carry out the transmission of the electrical signal from the transducing nociceptor to the dorsal horn of the spinal cord, from there to the brain stem, and then from the brain stem to the various parts of the brain such as the thalamus and the limbic system, where pain signals are processed and given context in the process of pain perception. Through modulation, the brain can then modify the sending of further pain impulses by signaling the release of neurotransmitters that either inhibit them (for example, serotonin and endorphins) or excite them.
The lumbar region (or lower back region) is made up of five vertebrae (L1-L5). In between these vertebrae lie fibrocartilage discs (intervertebral discs), which act as cushions, preventing the vertebrae from rubbing together while at the same time protecting the spinal cord. Nerves stem from the spinal cord through foramina within the vertebrae, providing muscles with sensations and motor associated messages. Stability of the spine is provided through ligaments and muscles of the back, lower back and abdomen. Small joints which prevent, as well as direct, motion of the spine are called facet joints (zygapophysial joints).
Causes of lower back pain are varied. Most cases are believed to be due to a sprain or strain in the muscles and soft tissues of the back. Overactivity of the muscles of the back can lead to an injured or torn ligament in the back which in turn leads to pain. An injury can also occur to one of the intervertebral discs (disc tear, disc herniation). Due to aging, discs begin to diminish and shrink in size, resulting in vertebrae and facet joints rubbing against one another. Ligament and joint functionality also diminishes as one ages, leading to spondylolisthesis, which causes the vertebrae to move much more than they should. Pain is also generated through lumbar spinal stenosis, sciatica and scoliosis. At the lowest end of the spine, some patients may have tailbone pain (also called coccyx pain or coccydynia). Others may have pain from their sacroiliac joint, where the spinal column attaches to the pelvis, called sacroiliac joint dysfunction which may be responsible for 22.6% of low back pain. Physical causes may include osteoarthritis, rheumatoid arthritis, degeneration of the discs between the vertebrae or a spinal disc herniation, a vertebral fracture (such as from osteoporosis), or rarely, an infection or tumor.
In the vast majority of cases, no noteworthy or serious cause is ever identified. If the pain resolves after a few weeks, intensive testing is not indicated.[unreliable source]
For correct diagnosis, non-specific low back pain must be differentiated from radiculopathy and serious spinal problems such as a tumor, infection or spinal fracture. Certain signs, termed "red flags," may indicate a more serious condition, and prompt a more extensive investigation using diagnostic imaging or laboratory testing; even so, most individuals seeking treatment for acute low back pain have one or more red flags but no serious underlying problem. With other causes ruled out, people with non-specific low back pain typically are treated symptomatically, without exact determination of the underlying cause.
X-rays, CT or MRI scans are not required in lower back pain except in the cases where "red flags" are present. If the pain is of a long duration X-rays may increase patient satisfaction. However routine imaging may be harmful to a person's health and more imaging is associated with higher rates of surgery but no resultant benefit. From 1994 to 2006, in the United States MRI scans of the lumbar region increased by more than 300%.
Risks of imaging
Complaints of lower back pain are one of the most common reasons why people visit doctors. Although many patients and doctors try to find the cause of the pain with imaging tests such as an X-ray, CT scan, or MRI, in most cases these tests are not necessary. Most people with lower-back pain feel better after a month regardless of whether they get imaging. Fewer than 1% of imaging tests identify the cause of a problem.
The negative effects of imaging include the following:
- The tests rarely result in a faster or better recovery
- X-rays and CT scans involve exposure to potentially harmful radiation
- They can detect harmless abnormalities which encourage the patient to request further unnecessary testing or to worry
- Testing for acute back pain often leads to unnecessary surgery
- The tests are expensive
Medical societies do not recommend imaging tests for lower back pain within a few weeks of the onset of pain as the pain is likely to subside.
Exercise is effective in preventing recurrence of non-acute pain, however in the treatment of acute episodes results are mixed. Proper lifting techniques may be useful. Lumbar support does not appear effective. Firm mattresses have demonstrated less effectiveness in preventing back pain than medium-firm mattresses.
Cigarette smoking impacts the success and proper healing of spinal fusion surgery in patients who undergo cervical fusion; rates of nonunion are significantly greater for smokers than for nonsmokers. Smoke and nicotine accelerate spine deterioration, reduce blood flow to the lower spine, and cause discs to degenerate.
For acute cases that are not debilitating, the treatment goal is to restore normal function and return the individual to work while minimizing pain. The condition is normally not serious, most often resolves without significant intervention, and recovery is aided by attempting to resume normal activity as soon as possible within the limits of pain; providing afflicted individuals with coping skills through reassurance of these facts is effective in hastening recovery. Low back pain may be best treated with conservative self-care, including: application of heat or cold, and continued activity within the limits of the pain.[unreliable source]
Engaging in physical activity within the limits of pain aids recovery. Prolonged bed rest (more than 2 days) is considered counterproductive. Even with cases of severe pain, some activity is preferred to prolonged sitting or lying down - excluding movements that would further strain the back.[unreliable source] Structured exercise in acute low back pain has demonstrated neither improvement nor harm. Heat application may have a modest benefit. The evidence for cold therapy however is limited.
Physical therapy can include heat, ice, massage, ultrasound, and electrical stimulation. Active therapies can consist of stretching, strengthening and aerobic exercises. Exercising to restore motion and strength to your lower back can be very helpful in relieving pain and preventing future episodes of low back pain.Treatment according to McKenzie method is somewhat effective for acute low back pain, but not for chronic low-back pain. The benefit in the short term does not appear clinically significant.
Short term use of pain and anti-inflammatory medications, such as NSAIDs or acetaminophen may help relieve the symptoms of lower back pain. NSAIDs are slightly effective for short-term symptomatic relief in patients with acute and chronic low-back pain without sciatica. Muscle relaxants for acute and chronic pain have some benefit, and are more effective in relieving pain and spasms when used in combination with NSAIDs. Oral steroids have not been shown to be useful.
It is not known if chiropractic care improves clinical outcomes in those with lower back pain more or less than other treatments. A 2012 Cochrane review found that spinal manipulation was no more effective than either inert interventions, sham manipulation, or other treatments and adding it to other treatment does not appear to increase the benefit. A 2010 systematic review found that most studies suggest SM achieves equal or superior improvement in pain and function when compared with other commonly used interventions for short, intermediate, and long-term follow-up. In 2007 the American College of Physicians and the American Pain Society jointly recommended that it be considered for people who do not improve with self care options. Acupuncture and massage is without substantial benefit.
Low back pain is more likely to be persistent among people who previously required time off from work because of low back pain, those who expect passive treatments to help, those who believe that back pain is harmful or disabling or fear that any movement whatever will increase their pain, and people who have depression or anxiety.[unreliable source] A number of factors predict disability from back pain and include those who have poor coping behaviors or who fear activity are about 2.5 times as likely to have poor outcomes at a year. Intensive multidisciplinary treatment programs may help subacute or chronic low back pain.[unreliable source] Behavioral therapy may be useful.
Exercise therapy appears to be slightly effective at reducing pain and improving function in the treatment of chronic low back pain. Compared to usual care, exercise therapy improved post-treatment pain intensity and disability, and long-term function. Exercise programmes are effective for chronic LBP up to 6 months after treatment cessation, evidenced by pain score reduction and reoccurrence rates. There is no evidence that one particular type of exercise therapy is clearly more effective than others. The Alexander technique appears useful for chronic back pain. There is tentative evidence to support the use of yoga.
Antidepressants appear ineffective in the treatment of chronic back pain even though some previous studies found them helpful. Tricyclic antidepressants are recommended in a 2007 guideline by the American College of Physicians and the American Pain Society. Prolotherapy, facet joint injections, and intradiscal steroid injections have not been found to be effective. Epidural corticosteroid injections provide only slight temporary relief of sciatica with no long term benefit. The role of narcotics for chronic low back pain is uncertain.
The effectiveness of spinal manipulation is more or less equal to other commonly prescribed treatment for chronic low-back pain, such as, exercise therapy, standard medical care or physiotherapy. Some national guidelines consider its use optional, some do not recommend and others suggest a short course in those who do not improve with other measures. Manipulation under anaesthesia, or medically assisted manipulation, currently has insufficient evidence to make any strong recommendations. Acupuncture may help chronic pain; however, a more recent randomized controlled trialsuggested insignificant difference between real and sham acupuncture. Transcutaneous electrical nerve stimulation (TENS) has not been found to be effective in chronic lower back pain. Massage therapy may benefit some to those with prolonged pain.
Surgery may be indicated when conservative treatment is not effective or when a person develops progressive and functionally limiting neurological symptoms such as leg weakness, bladder or bowel incontinence. Spinal fusion has been shown not to improve outcomes in those with simple chronic low back pain.Discectomy, in those with a herniated disc causing nerve root compression, resulted in better outcomes at one year but not in four to ten years. Benefits of spinal surgery are limited when dealing with degenerative discs. Surgical implants increased the risk with no added improvement in pain or function.
Most people with acute lower back pain recover completely over a few weeks. At 6 weeks complete recovery rates have been reported at between 40-90%.
Low back pain that lasts at least one day and limits activity is a very common and widespread complaint. Globally, approximately 11.9% of people have lower back pain at any given point in time, and nearly one quarter (23.2%) report having it at some point over any given one-month period. Prevalence is highest among women, and among people aged 40–80 years, with the overall number of individuals afflicted expected to increase as the population ages. Women may be more prone to the complaint due to pain related to osteoporosis, menstruation or pregnancy, or women may be more willing than men to report pain due to differences in social expectations between the two groups. Prevalence is elevated among adolescents, with females reporting it earlier than males, possibly showing a correlation between low back pain and the onset of puberty, as females enter puberty earlier than males. Over a lifetime, 80% of people have lower back pain, with the difficulty most often beginning between 20 and 40 years old. Of American adults, 26% report pain of at least one day in duration every three months. 41% of adults aged between 26 and 44 years reported having back pain in the previous 6 months.
Low back pain has been with humans since at least the Bronze Age. The oldest known surgical treatise - the Edwin Smith Papyrus, dating to about 1500 BCE - describes a diagnostic test and treatment for a physician to use on encountering a vertebral sprain. Hippocrates (c. 460 BCE – c. 370 BCE) was the first to make use of terms for sciatic pain and low back pain; Galen (active mid to late second century CE) detailed the concepts. Physicians through the end of the first millennium did not attempt back surgery of any kind, and recommended only watchful waiting. Through the Medieval period, folk medicine practitioners provided treatments for back pain based on the belief that it was caused by spirits.
By the start of the 20th century, physicians thought low back pain was simply caused by inflammation of or damage to the nerves, with neuralgia and neuritis frequently cited; the popularity of such proposed neural main etiologies declined steadily throughout the century. In the 1920s and 30s, new theories for the cause of low pack pain arose, with physicians proposing a combination of nervous system and psychological disorders such as neurasthenia, hysteria, or psychogenesis. Muscular causes such as "muscular rheumatism" (now called fibromyalgia) were cited with increasing frequency as well.
Emerging technologies such as radiography gave physicians new diagnostic tools, which revealed the intervertebral disk as a source for back pain. In 1938, orthopedic surgeon Joseph S. Barr reported on cases of disk-related sciatica improved or cured with back surgery; consequently, in the 1940s, the vertebral disk model of low back pain took over, dominating the literature through the 1980s, especially after the rise of new imaging technologies such as CT and MRI. Such discussion later subsided as further research showed that it was actually relatively uncommon for disk problems to be the source of the pain, but even with the knowledge that diagnostic tools could show abnormalities probably unrelated to the patient's pain, physicians would still look to the tools' results instead of physical examinations for diagnosis and treatment plans. Since then, physicians have come to question whether it is likely that they will be able to identify a specific cause for a complaint of low back pain, or whether finding one is even necessary, as most complaints resolve themselves within six to 12 week regardless of treatment.
In the United States, estimates of the costs of low back pain range between $38 and $50 billion a year and there are 300,000 operations annually. Back and neck operations are the third most common form of surgery in the United States.Between 1990 and 2001 there was a 220% increase in spinal fussions in the United States, despite the fact that during that period there were no changes, clarifications, or improvements in the indications for surgery or new evidence of improved effectiveness.
Women may experience acute low back pain due to certain medical conditions of the female reproductive system, including endometriosis, ovarian cysts, ovarian cancer, or uterine fibroids.
An estimated 50-70% of pregnant women experience back pain. As one gets farther along in the pregnancy, due to the additional weight of the fetus, one’s center of gravity will shift forward causing one’s posture to change. This change in posture leads to increasing lower back pain..