“Sciatica is a set of symptoms including pain that may be caused by general compression and/or irritation of one of five nerve roots that give rise to the sciatic nerve, or by compression or irritation of the sciatic nerve itself. The pain is felt in the lower back, buttock, and/or various parts of the leg and foot. In addition to pain, which is sometimes severe, there may be numbness, muscular weakness, and difficulty in moving or controlling the leg. Typically, the symptoms are only felt on one side of the body.
The medical term for sciatica is a radiculopathy, which means that a spinal disc has extended beyond its normal position and is irritating the Radicular nerve (nerve root) in the lower back, which connects with the sciatic nerve. The sciatic nerve branches off as it travels down the lower extremity through the back of the leg. Sciatic pain can be experienced along this nerve route.
Although sciatica is a relatively common form of low back pain and leg pain, the true meaning of the term is often misunderstood. Sciatica is a set of symptoms rather than a diagnosis for what is irritating the root of the nerve, causing the pain. This point is important, because treatment for sciatica or sciatic symptoms will often be different, depending upon the underlying cause of the symptoms.
Causes of sciatica
Sciatica is generally caused by the compression of lumbar nerves L4 or L5 or sacral nerves S1, S2 or S3, or far less commonly, by compression of the sciatic nerve itself. When sciatica is caused by compression of a dorsal nerve root (radix) it is considered a lumbar radiculopathy (or radiculitis when accompanied with an inflammatory response) from a spinal disc herniation (a herniated intervertebral disc in the spine), or from roughening, enlarging, and/or misaligning of the vertebrae (spondylolisthesis), or degenerated discs. Sciatica due to compression of a nerve root is one of the most common forms of radiculopathy.
"Pseudo-sciatica," which causes symptoms similar to spinal nerve root compression, is caused by the compression of peripheral sections of the nerve, usually from soft tissue tension in the piriformis or related muscles (see piriformis syndrome and see below).
Spinal disc herniation
One cause of sciatica is a spinal disc herniation, pressing on one of the sciatic nerve roots. The spinal discs are composed of a tough spongiform ring of cartilage (annulus fibrosus) with a more malleable center (nucleus pulposis). The discs separate the vertebrae, thereby allowing room for the nerve roots to properly exit through the spaces between the L4, L5, and sacral vertebrae. The discs cushion the spine from compressive forces, but are weak to pressure applied during rotational movements. That is why a person who bends to one side, at a bad angle to pick something up, may more likely herniate a spinal disc than a person falling from a ladder and landing on his or her back. Herniation of a disc occurs when the liquid center of the disc bulges outwards, tearing the external ring of fibers, extrudes into the spinal canal, and compresses a nerve root against the lamina or pedicle of a vertebra, thus causing sciatica. This extruded liquid from the nucleus pulposus may cause inflammation and swelling of surrounding tissue which may cause further compression of the nerve root in the confined space in the spinal canal.
Sciatica can be caused by tumours impinging on the spinal cord or the nerve roots. Severe back pain extending to the hips and feet, loss of bladder or bowel control, or muscle weakness, may result from spinal tumours. Trauma to the spine, such as from a car accident, may also lead to sciatica.
Spinal stenosis
Other compressive spinal causes include spinal stenosis, a condition wherein the spinal canal (the spaces through which the spinal cord runs) narrows and compresses the spinal cord, cauda equina, and/or sciatic nerve roots. This narrowing can be caused by bone spurs, vertebral dislocation, inflammation, or herniated disc which decreases available space for the spinal cord, thus pinching nerves from the spinal cord that travel to the sciatic nerve and irritating them with friction.
Piriformis syndrome
In 15% of the population, the sciatic nerve runs through the piriformis muscle rather than beneath it. When the muscle shortens or spasms due to trauma, it can compress or strangle the sciatic nerve beneath the muscle. This cause of sciatic symptoms is piriformis syndrome. This may be the major cause of sciatica when the nerve root is normal.
The risk of self-inflicted sciatica has increased in recent years with the fashion trend of lower-hanging trousers as well as lower-positioning of the pockets. For instance, sitting on a wallet for prolonged hours every day can cause self-inflicted sciatica. Symptoms of numbness and/or pain behind the knee cap are associated with this form of sciatica.
Sacroiliac joint dysfunction
Another cause of sciatic symptoms is sacroiliac joint dysfunction. Unhealthy posture, habits such as sitting in chairs for excessive lengths of time and sleeping in the foetal position, along with insufficient stretching and exercise of the relevant myofascial areas, can lead to both the vertebral and soft tissue problems associated with sciatica.
Trigger points
Another source of sciatic symptoms is active trigger points of the lower back and the gluteus muscles.[citation needed] In this case, the referred pain is not consequent to compression of the sciatic nerve, though the pain distribution down the buttocks and leg is similar. Trigger points occur when muscles become ischemic (low blood flow) due to injury or chronic muscular contraction. The most commonly associated muscles with trigger points triggering sciatic symptoms are: the quadratus lumborum, the gluteus medius, the gluteus minimus, and the deep hip rotators.
Pregnancy
Sciatica may also be experienced in late pregnancy, primarily resulting from the uterus pressing on the sciatic nerve, and, secondarily, from the muscular tension and / or vertebral compression consequent to carrying the extra weight of the fetus, and the postural changes inherent to pregnancy
Diagnosis and treatment
Because of the many conditions which can compress nerve roots and cause sciatica, treatment and symptoms often differ from patient to patient. Diagnostic tests can come in the form of a series of exams a physician will perform. Patients will be asked to adopt numerous positions and actions such as squatting, walking on toes, bending forward and backward, rotating the spine, sitting, lying on back, and raising one leg at a time. Increased pain will occur during some of these activities.
Treatment of the underlying cause of the compression is often the most effective course. When the cause is due to a prolapsed or lumbar disc herniation, research has shown that, with supportive treatment to help relieve pain, 90% of disc prolapse will recover with no specific intervention. Genetics appear to influence the risk of developing disc herniation.
Imaging methods such as MR neurography may help diagnosis and treatment of sciatica. MR neurography has been shown to diagnose 95% of severe sciatica patients, while as few as 15% of sciatica sufferers in the general population are diagnosed with disc-related problems. MR neurography is a modified MRI technique using MRI software to provide better pictures of the spinal nerves and the effect of compression on these nerves. MR neurography may help diagnose piriformis syndrome which is another cause of sciatica that does not involve disc herniation.
Most cases of sciatica can be treated by one or more of the following:
1.Acupuncture
2.Anti-inflammatory medications (for example NSAIDs or oral steroids)
3.Chiropractic
4.Osteopathy
5.Pain medication (for example acetaminophen)
6.Physical therapy
7.Surgery
8.Stretching exercises
9.Structural integration
10.Yoga
Specific surgical techniques include:
Intradiscal Electrothermoplasty (IDET)
A needle is inserted into the affected disc, guided by x-ray. A wire is then threaded down through the needle and into the disc until it lies along the inner wall of the annulus. The wire is then heated which destroys the small nerve fibers that have grown into the cracks and have invaded the degenerating disc. The heat also partially melts the annulus, which triggers the body to generate new reinforcing proteins in the fibers of the annulus
Radiofrequency Discal Nucleoplasty (Coblation Nucleoplasty)
A needle is inserted into the affected disc, although instead of a heating wire, a special RF probe (radio frequency) is used. This probe generates a highly focused plasma field with enough energy to break up the molecular bonds of the gel in the nucleus, essentially vaporizing some of the nucleus. The result is that 10-20% of the nucleus is removed which decompresses the disc and reduces the pressure both on the disc and the surrounding nerve roots. This technique may be more beneficial for sciatica type of pain than the IDET, since nucleoplasty can actually reduce the disc bulge, which is pressing on a nerve root. The high-energy plasma field is actually generated at relatively low temperatures, so danger to surrounding tissues is minimized.
The term sciatica describes the symptoms of leg pain and possibly tingling, numbness or weakness that travels from the low back through the buttock and down the large sciatic nerve in the back of the leg. The vast majority of people who experience sciatica get better with time (usually a few weeks or months) and find pain relief with non-surgical sciatica treatment. For others, however, sciatica can be severe and debilitating.
The clinical diagnosis of sciatica is referred to as a "radiculopathy", which means simply that a disc has protruded from its normal position in the vertebral column and is putting pressure on the radicular nerve (nerve root) in the lower back, which forms part of the sciatic nerve.
An important thing to understand is that sciatica is a symptom of a problem — of something compressing or irritating the nerve roots that comprise the sciatic nerve — rather than a medical diagnosis or medical disorder in and of itself. This is an important distinction because it is the underlying diagnosis (vs. the symptoms of sciatica) that often needs to be treated in order to relieve sciatic nerve pain.
Sciatica occurs most frequently in people between 30 and 50 years of age. Often a particular event or injury does not cause sciatica, but rather it tends to develop as a result of general wear and tear on the structures of the lower spine.
Sciatica symptoms
For some people, the pain from sciatica can be severe and debilitating. For others, the pain might be infrequent and irritating, but has the potential to get worse.
While sciatica can be very painful, it is rare that permanent nerve damage (tissue damage) will result. Most sciatica pain syndromes result from inflammation and will get better within two weeks to a few months. Also, because the spinal cord is not present in the lower (lumbar) spine, a herniated disc in this area of the anatomy does not present a danger of paralysis.
Sciatica symptoms that may constitute a medical emergency include:
1.Progressive weakness in the leg
2.Bladder/bowel incontinence or dysfunction.
Common Causes of Sciatica:
1.Lumbar herniated disc
2.Spinal stenosis
3.Degenerative disc disease
4.Spondylolisthesis
Patients with either of the above symptoms may have cauda equina syndrome and should seek immediate medical attention. In general, patients with complicating factors should contact their doctor if sciatica occurs, including people who (1) Have been diagnosed with cancer; (2) Take steroid medication, (3) Abuse drugs, (4) Have unexplained, significant weight loss, or (5) Have HIV.
Sciatica medical definition: Radiculopathy
To clarify medical terminology, the term sciatica (often misspelled as ciatica, cyatica or siatica) is often used very broadly to describe any form of pain that radiates into the leg. However, this is not technically correct. True sciatica occurs when the sciatic nerve is pinched or irritated and the pain along the sciatic nerve is caused by this nerve (radicular pain) and is called a radiculopathy. When the pain is referred to the leg from a joint problem (called referred pain), using the term sciatica is not technically correct. This type of referred pain (e.g. from arthritis or other joint problems) is quite common.
Practical point
Symptoms of sciatica pain can vary greatly but usually decrease after a few weeks or months with non-surgical treatment.
Sciatica treatment
Sciatica nerve pain is caused by a combination of pressure and inflammation on the nerve root, and treatment is centered on relieving both of these factors. Typical sciatica treatment include:
Non-surgical sciatica treatments, which may include one or a combination of medical treatments and alternative (non-medical) treatments, and almost always includes some form of exercise and stretching. The goals of non-surgical sciatica treatment should include both relief of sciatica pain and prevention of future sciatica symptoms.
Sciatica surgery, such as microdiscectomy or lumbar laminectomy and discectomy, to remove the portion of the disc that is irritating the nerve root. This surgery is designed to help relieve both the pressure and inflammation and may be warranted if the sciatic nerve pain is severe and has not been relieved with appropriate manual or medical treatments.
Active exercise is important for sciatica (radiculopathy) relief
While it may seem counterintuitive, exercise is usually better for healing sciatic pain than bed rest. Patients may rest for a day or two after their sciatica flares up, but after that time period, inactivity will usually make the pain worse. Without exercise and movement, the back muscles and spinal structures become deconditioned and less able to support the back.
The deconditioning and weakening can lead to back injury and strain, which causes additional back pain. Exercise is also important for the health of the spinal discs. Movement helps exchange nutrients and fluids within the discs to keep them healthy.
Many sciatica exercises focus on strengthening the abdominal and back muscles in order to provide more support for the back. Stretching exercises for sciatica target muscles that cause pain when they are tight and inflexible. When patients engage in a regular program of gentle strengthening and stretching exercises, they can recover more quickly from a flare up of sciatica and can help to prevent future episodes of pain.
Specific sciatica exercises depend on the cause of the pain
A physical therapist, certified athletic trainer (ATC), chiropractor, physiatrist or other spine specialist who treats the back pain and leg pain associated with sciatica may recommend exercise as part of a treatment program. It is important to first get an accurate diagnosis for the cause of sciatic pain, as the specific exercises recommended will depend on the cause of the sciatica. It is also important to get a diagnosis before starting any sciatica exercises because, while rare, sciatic pain can be caused by some serious medical conditions (such as an infection or tumor) that require prompt medical attention.
Caring for sciatica should be considered part of one's daily living, not just something to add to the routine at the end of the day. In addition to an exercise routine, patients with sciatica should minimize everyday stress on the lower back, including using good ergonomics while lifting, maintaining good posture, making sure the lower back is supported while sitting, and avoiding standing for long periods of time.
Practical point
For many people with herniated discs, extension exercises that arch the spine backward rather than flex it forward will provide more relief.
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