Updated: Nov 26, 2020
Most commonly, mechanical issues and soft-tissue injuries are the cause of low back pain. These injuries can include damage to the intervertebral discs, compression of nerve roots, and improper movement of the spinal joints. The most common cause of lower back pain is a torn or pulled muscle and/or ligament.
Muscle Strain and Ligament Sprain
Strains occur when a muscle is stretched too far and tears, damaging the muscle itself.
Sprains happen when over-stretching and tearing affects ligaments, which connect the bones together.
For practical purposes, it does not matter whether the muscle or ligament is damaged, as the symptoms and treatment are the same.
Common causes of sprain and strain include:
Lifting a heavy object, or twisting the spine while lifting
Sudden movements that place too much stress on the low back, such as a fall
Poor posture over time
Sports injuries, especially in sports that involve twisting or large forces of impact
While sprains and strains do not sound serious and do not typically cause long-lasting pain, the acute pain can be quite severe.
Causes of Chronic Lower Back Pain
Pain is considered chronic once it lasts for more than three months and exceeds the body’s natural healing process. Chronic pain in the low back often involves a disc problem, a joint problem, and/or an irritated nerve root. Common causes include:
Lumbar herniated disc The jelly-like center of a lumbar disc can break through the tough outer layer and irritate a nearby nerve root. The herniated portion of the disc is full of proteins that cause inflammation when they reach a nerve root, and inflammation, as well as nerve compression, cause nerve root pain. The disc wall is also richly supplied by nerve fibers, and a tear through the wall can cause severe pain.
Degenerative disc disease At birth, intervertebral discs are full of water and at their healthiest. As people age over time, discs lose hydration and wear down. As the disc loses hydration, it cannot resist forces as well, and transfers force to the disc wall that may develop tears and cause pain or weakening that can lead to a herniation. The disc can also collapse and contribute to stenosis.
Facet joint dysfunction There are two facet joints behind each disc at each motion segment in the lumbar spine. These joints have cartilage between the bones and are surrounded by a capsular ligament, which is richly innervated by nerves. These joints can be painful by themselves, or in conjunction with disc pain.
Sacroiliac joint dysfunction. The sacroiliac joint connects the sacrum at the bottom of the spine to each side of the pelvis. It is a strong, low-motion joint that primarily absorbs shock and tension between the upper body and the lower body. The sacroiliac joint can become painful if it becomes inflamed (sacroiliitis) or if there is too much or too little motion of the joint.
Spinal stenosis This condition causes pain through narrowing of the spinal canal where the nerve roots are located. The narrowing can be central, forminal, or both, and can be at a single level or multiple levels in the lower back.
Spondylolisthesis This condition occurs when one vertebra slips over the adjacent one. The pain can be caused by instability (back) or compression of the nerves (leg).
Osteoarthritis This condition results from wear and tear of the disc and facet joints. It causes pain, inflammation, instability, and stenosis to a variable degree, and can occur at a single level or multiple levels of the lower spine. Spinal osteoarthritis is associated with aging and is slowly progressive. It is also referred to as spondylosis or degenerative joint disease.
Deformity. Curvature of the spine can include scoliosis or kyphosis. The deformity may be associated with lower back pain if it leads to the breakdown of the discs, facet joints, sacroiliac joints or stenosis.
Trauma Acute fractures or dislocations of the spine can lead to pain. Lower back pain that develops after a trauma, such as a motor vehicle accident or a fall, should be medically evaluated.
Compression fracture A fracture that occurs in the cylindrical vertebra, in which the bone essentially caves in on itself, can cause sudden pain. This type of fracture is most common due to weak bones, such as from osteoporosis, and is more common in older people.
It is important to note that the presence of one or more of these conditions does not necessarily mean that is the cause of pain. For example, osteoarthritis or degenerative disc disease could appear on an imaging study but the person may not report pain.
Less Common Causes of Low Back Pain
While considerably less common, low back pain may also be caused by:
Infection Also called osteomyelitis, a spinal infection is rare but can cause severe pain and is life threatening if untreated. It can be caused by surgical procedures, injections, or spread through the blood stream. Patients with a compromised immune system are more susceptible to developing an infection in the spine.
Tumor Most spinal tumors start in another part of the body and metastasize to the spine. The most common tumors that spread to the spine start from cancer in the breast, prostate, kidney, thyroid, or lung. Any new symptoms of back pain in a patient with a known diagnosis of cancer should be evaluated for possible spinal metastasis.
Lower Back Pain Symptoms
The lumbar spine, or low back, is a remarkably well-engineered structure of interconnecting bones, joints, nerves, ligaments, and muscles all working together to provide support, strength, and flexibility. However, this complex structure also leaves the low back susceptible to injury and pain.
This article presents a model for understanding symptoms, physical findings, imaging studies, and injection techniques to come to a precise diagnosis.
Once an accurate diagnosis of the cause of the lower back pain is attained, treatment options can be selected based on today’s best medical practices.
The Lumbar Spine, What Can Go Wrong
The low back supports the weight of the upper body and provides mobility for everyday motions such as bending and twisting. Muscles in the low back are responsible for flexing and rotating the hips while walking, as well as supporting the spinal column. Nerves in the low back supply sensation and power the muscles in the pelvis, legs, and feet.
Most acute low back pain results from injury to the muscles, ligaments, joints, or discs. The body also reacts to injury by mobilizing an inflammatory healing response. While inflammation sounds minor, it can cause severe pain.
There is a significant overlap of nerve supply to many of the discs, muscles, ligaments, and other spinal structures, and it can be difficult for the brain to accurately sense which is the cause of the pain. For example, a degenerated or torn lumbar disc can feel the same as a pulled muscle – both creating inflammation and painful muscle spasm in the same area. Muscles and ligaments heal rapidly, while a torn disc may or may not. The time course of pain helps determine the cause.
Range of Lower Back Pain Symptoms
Low back pain can incorporate a wide variety of symptoms. It can be mild and merely annoying or it can be severe and debilitating. Low back pain may start suddenly, or it could start slowly—possibly coming and going—and gradually get worse over time.
Depending on the underlying cause of the pain, symptoms can be experienced in a variety of ways. For example:
Pain that is dull or achy, contained to the low back
Stinging, burning pain that moves from the low back to the backs of the thighs, sometimes into the lower legs or feet; can include numbness or tingling (sciatica)
Muscle spasms and tightness in the low back, pelvis, and hips
Pain that worsens after prolonged sitting or standing
Difficulty standing up straight, walking, or going from standing to sitting
In addition, symptoms of lower back pain are usually described by type of onset and duration:
Acute pain. This type of pain typically comes on suddenly and lasts for a few days or weeks, and is considered a normal response of the body to injury or tissue damage. The pain gradually subsides as the body heals.
Subacute low back pain. Lasting between 6 weeks and 3 months, this type of pain is usually mechanical in nature (such as a muscle strain or joint pain) but is prolonged. At this point, a medical workup may be considered, and is advisable if the pain is severe and limits one’s ability to participate in activities of daily living, sleeping, and working.
Chronic back pain. Usually defined as lower back pain that lasts over 3 months, this type of pain is usually severe, does not respond to initial treatments, and requires a thorough medical workup to determine the exact source of the pain.
Types of Low Back Pain
There are many ways to categorize low back pain – two common types include:
Mechanical pain. By far the most common cause of lower back pain, mechanical pain (axial pain) is pain primarily from the muscles, ligaments, joints (facet joints, sacroiliac joints), or bones in and around the spine. This type of pain tends to be localized to the lower back, buttocks, and sometimes the top of the legs. It is usually influenced by loading the spine and may feel different based on motion (forward/backward/twisting), activity, standing, sitting, or resting.
Radicular pain. This type of pain can occur if a spinal nerve root becomes impinged or inflamed. Radicular pain may follow a nerve root pattern or dermatome down into the buttock and/or leg. Its specific sensation is sharp, electric, burning-type pain and can be associated with numbness or weakness (sciatica). It is typically felt on only one side of the body.
There are many additional sources of pain, including claudication pain (from stenosis) myelopathic pain, neuropathic pain, deformity, tumors, infections, pain from inflammatory conditions (such as rheumatoid arthritis or ankylosing spondylitis), and pain that originates from another part of the body and presents in the lower back (such as kidney stones, or ulcerative colitis).
It is also possible for low back pain to develop with no definitive cause. When this happens, the primary focus is on treating the symptoms (rather than the cause of the symptoms) and the patient’s overall health.
For subacute and chronic lower back pain, a thorough diagnosis is important to lay the foundation for appropriate treatment and rehabilitation. Lower back pain treatment reduces the likelihood of recurrent back pain flare-ups and helps prevent the development of chronic lower back pain.
Common Symptoms of Lower Back Problems
Specifically identifying and describing symptoms can help lead to a more accurate diagnosis and effective treatment plan.
Low back pain is typically characterized by a combination of the following symptoms:
Dull, aching pain
Pain that remains within the low back (axial pain) is usually described as dull and aching rather than burning, stinging, or sharp. This kind of pain can be accompanied by mild or severe muscle spasms, limited mobility, and aches in the hips and pelvis.
Pain that travels to the buttocks, legs, and feet
Sometimes low back pain includes a sharp, stinging, tingling or numb sensation that moves down the thighs and into the legs and feet, also called sciatica. Sciatica is caused by irritation of the sciatic nerve, and is usually only felt on one side of the body.
Pain that is worse after prolonged sitting
Sitting puts pressure on the discs, causing low back pain to worsen after sitting for long periods of time. Walking and stretching can alleviate low back pain quickly, but returning to a sitting position may cause symptoms to return.
Pain that feels better when changing positions
Depending on the underlying cause of pain, some positions will be more comfortable than others. For example, with spinal stenosis walking normally may be difficult and painful, but leaning forward onto something, such as a shopping cart, may reduce pain. How symptoms change with shifting positions can help identify the source of pain.
Pain that is worse after waking up and better after moving around
Many who experience low back pain report symptoms that are worse first thing in the morning. After getting up and moving around, however, symptoms are relieved. Pain in the morning is due to stiffness caused by long periods of rest, decreased blood flow with sleep, and possibly the quality of mattress and pillows used.
Of course, there are other ways people experience low back pain. Low back pain varies on an individual level, and many factors influence the pain experience, including mental and emotional health, financial stress, or exercise and activity level.
Onset of Low Back Pain Symptoms
Depending on the cause of low back pain, the onset of symptoms can vary widely. Back pain may include:
Pain that develops slowly over time
Symptoms caused by repetitive motions or stress-inducing positions tend to come on slowly and progressively worsen. Pain may develop after certain activities or at the end of a long day, and may feel like a constant ache.
Pain that comes and goes, but worsens over time
Low back pain caused by degenerative disc disease can be felt off and on, but pain flare-ups get progressively more severe over a long period of time.
Immediate pain after an injury
Sudden or jarring movements can damage the spine and its supportive muscles, causing immediate, acute pain.
Delayed symptoms after injury
Sometimes symptoms develop or get worse a few hours or days after an accident or injury. Delayed pain is generally thought of as a side effect of natural healing processes of muscles.
Symptoms That Require Immediate Attention
Sometimes low back pain can signal a serious underlying medical condition. People who experience any of the following symptoms are advised to seek immediate care.
Loss of bladder and bowel control
Recent weight loss not due to lifestyle changes, such as diet and exercise
Fever and chills
Severe, unrelenting pain in the abdomen
Additionally, people who experience pain symptoms after a major trauma (such as a car accident) are advised to see a doctor. If low back pain interferes with daily activities, mobility, sleep, or if there are other troubling symptoms, medical attention should be sought.
Chronic low back pain is usually correlated with other symptoms. Most people with ongoing low back pain and/or leg pain report difficulty with sleeping (falling asleep and/or staying asleep), depression and anxiety.
Diagnosing Lower Back Pain
Obtaining an accurate diagnosis that identifies the underlying cause of the pain, and doesn’t just correlate to the symptoms, is important in guiding treatment.
As a foundation of the diagnostic process, the patient provides a detailed description of symptoms and medical history. From this information, a doctor will usually have a general idea of the source of the patient’s pain.
Before starting a physical exam, the patient will be asked to provide information regarding symptoms and medical history. Inquiries typically include:
Information about current symptoms
Is the pain better or worse at certain times of day, such as waking up or after work? How far does the pain spread? Are there other symptoms at the same time, such as weakness or numbness? What does the pain feel like—achy, sharp, tight, dull, hot, stinging?
Does the person lead a generally more active or sedentary lifestyle? For example, does work require sitting at a desk or standing at an assembly line for long periods of time? How often does the person exercise?
As a general rule, how many hours of sleep does the patient get? What sleep position is preferred? What kind of and/or quality of mattress and pillow does the patient use?
What kind of posture feels comfortable or uncomfortable? Does the patient typically sit upright or slouch?
Has the person had any recent injuries? Has there been an injury in the past that might be relevant now?
Answers to these questions provide a doctor with a fuller picture of the patient’s daily life, indicating more specific possibilities for low back pain. A medical history is often the most powerful tool for finding a diagnosis.
The goal of a physical exam is to further narrow down possible causes of pain. A typical physical for low back pain includes some combination of the following steps:
A doctor will feel by hand (also called palpation) along the low back to locate any muscle spasms or tightness, areas of tenderness, or joint abnormalities.
Diagnosis will likely include a motor exam, which involves manual movement of hip, knee and big toe extension and flexion (movement forward and backward) as well as ankle movement. A sensory exam will likely include testing the patient’s reaction to light touch, a pin prick, or other senses in the lower trunk, buttock and legs.
Range of motion test
The patient may be asked to bend or twist in certain positions. These activities are done to look for positions that worsen or recreate pain, and to see if certain movements are limited by discomfort.
The patient’s reflexes in the legs will be checked to evaluate weakened reflexes and decreased muscle strength. If reflexes are diminished, a nerve root might not be responding as it should.
Leg raise test
The patient is asked to lay on the back and raise one leg as high and as straight as possible. If this leg raise test recreates low back pain, a herniated disc might be suspected.
Usually, a doctor is able to diagnose low back pain based on the information gleaned from a medical history and a physical exam, and further testing is not needed.
Diagnostic Imaging Tests
An imaging scan is sometimes needed to gain more information on the cause of a patient’s pain. A diagnostic imaging test may be indicated if the patient’s pain is severe and does not get better with nonsurgical treatments.
Common imaging tests include:
X-rays are used to look at the bones of the spine. X-rays show abnormalities, such as arthritis, fractures, bone spurs, or tumors.
A CT scan/Myelogram provides a cross-sectioned image of the spine. In a CT scan(Computer Tomography) an x-ray is sent through the spine, which a computer picks up and reformats into a 3D image. This detailed image allows doctors to look closely at the spine from different angles. Sometimes a myelogram is performed in tandem with a CT scan, in which dye is injected around nerve roots to highlight spinal structures, giving the image more clarity.
An MRI, or Magnetic Resonance Imaging scan, provides a detailed image of spinal structures without using the radiation required with x-rays. An MRI of the spine can detect abnormalities with soft tissues, such as muscles, ligaments, and intervertebral discs. An MRI might also be used to locate misalignments or joint overgrowth in the spine.
Injection studies are fluoroscopic-directed injections of local anesthetic and steroid medication into specific anatomic structures. They are helpful in confirming the source of the pain. They are used in diagnosis, in conjunction with rehabilitation, and are considered predictive of surgical outcomes.
Sometimes doctors know what is causing low back pain but not exactly where it is happening, so an imaging test will be used to locate the source more specifically. Imaging tests are also used for patients having surgery so doctors and surgeons can plan the procedure beforehand.
Early Treatments for Lower Back Pain
Many treatment options for low back pain can be tailored to an individual patient’s needs. Treatments include care administered at home, medicinal remedies, alternative care, or surgery.
Depending on the patient’s diagnosis, some treatments may be more effective than others. Many people find that a combination of treatments is best.
Self-Care for Low Back Pain
Basic remedies applied at home can be effective for treating mild or acute pain from muscle strain, as well as reducing the effects of chronic, severe pain. Self-care is administered by the individual and can easily be adjusted. These methods include:
Short rest period
Many episodes of lower back pain can be improved by briefly avoiding strenuous activity. It is not advised to rest for more than a few days, as too much inactivity can make healing more difficult.
One variant of resting is to stay active but avoid activities and positions that aggravate the pain. For example, if long periods of sitting in a car or at a desk make the pain worse, then set a timer to get up every 20 minutes and walk around or gently stretch. If standing makes the pain worse, avoid chores that require standing such as washing dishes at the sink. Avoiding, or minimizing, activities and positions that worsen the pain will help prevent or reduce painful back spasms and allow for a better healing environment.
Heat from a warm bath, infra-red lamp, hot water bottle, electric heating pad, or chemical or adhesive heat wraps can relax tense muscles and improve blood flow. Increased blood flow brings nutrients and oxygen that muscles need to heal and stay healthy. If the low back is painful due to inflammation, ice or cold packs can be used to reduce swelling. It’s important to protect the skin while applying heat or ice to prevent tissue damage.
Alternating heat and ice can be especially helpful when returning to activity: applying heat before activities helps relax muscles, allowing for better flexibility and mobility; applying ice after activity reduces the chances of an area becoming irritated and swollen from exercise.
Over-the-counter pain medications
The most common over-the-counter (OTC) medications are aspirin, ibuprofen and acetaminophen. Aspirin, ibuprofen, and naproxen are anti-inflammatory medicines, which alleviate low back pain caused by a swollen nerves or muscles. Acetaminophen works by interfering with pain signals sent to the brain.
Self-care treatments generally do not need guidance from a doctor, but should be used carefully and attentively and not for more then 10-15 days. Any type of medication carries possible risks and side effects. If a patient is unsure which kinds of self-care would work best, talking to a doctor is advised.
Exercises for Low Back Pain
Exercises and physiotherapy should always be taken only after a consultation from a Spine Doctor (A Neurosurgeon or an Orthopedician) who would evaluate the patient’s medical condition and would rule out any chances of further injury which can happen if Physiotherapy is initiated in an ‘un-stable’ spine. Types of exercises used to rehabilitate the spine include: