Sciatica is the name given to pain caused by irritation of the sciatic nerve. Anything that irritates this nerve can cause pain, ranging from mild to severe.
Sciatica is usually caused by a compressed nerve root in the lumbar (lower) spine. Often, the term "sciatica" is confused with general back pain. However, sciatica is not just limited to the back.
The sciatic nerve is the longest and widest nerve in the human body. It runs from the lower back, through the buttocks, and down the legs, ending just below the knee.
This nerve controls several muscles in the lower legs and supplies sensation to the skin of the foot, and the majority of the lower leg.
Sciatica is not a condition, but rather a symptom of another problem involving the sciatic nerve. Some experts estimate that up to 40 percent of people will experience sciatica at least once in their life.
Fast facts on sciatica
Here are some key points about sciatica. More detail and supporting information is in the main article.
- The sciatic nerve is the longest nerve in the human body
- The most common cause of sciatica is a slipped (herniated) disk
- Cognitive behavioral therapy can help some people manage the pain of sciatica
- Sciatica is not a condition, it is a symptom
Overview of the types of sciatica
The sciatic nerve branches from the lower back, through the buttocks, and down the legs.
Sciatica is often split into two categories:
Acute sciatica (short-term)
Acute sciatica does not typically require professional treatment; OTC painkillers combined with hot and cold packs and exercise can significantly reduce symptoms.
Acute sciatica normally lasts 4-8 weeks.
Chronic sciatica (long-term)
Chronic sciatica, on the other hand, may require physical therapy, which can include exercise, applied heat, and other techniques. In rare cases, surgery might be required.
Chronic sciatica persists for 8 weeks or more.
Causes of sciatica
Sciatica is a common symptom of several different medical conditions; however, an estimated 90 percent of cases are due to a herniated (slipped) disk.
The spinal column is made up of three parts:
- Vertebrae (individual bones in the spine that protect underlying nerves)
Disks are made of cartilage, which is a strong and resilient material; the cartilage acts as a cushion between each vertebrae and allows the spine to be flexible.
A herniated disk occurs when a disk is temporarily pushed out of place, putting pressure on the sciatic nerve.
Other causes of sciatica include:
- Lumbar spinal stenosis - a narrowing of the spinal cord in the lower back that may compress the sciatic nerve.
- Spondylolisthesis - a condition where a disk slips forward over the vertebra below it, pinching the sciatic nerve.
- Tumors within the spine may compress the root of the sciatic nerve.
- Infection within the spine.
- Injury within the spine.
- Cauda equina syndrome - a rare, but serious condition that affects the nerves in the lower part of the spinal cord; it requires immediate medical attention. Cauda equina syndrome may permanently damage the nervous system and even lead to paralysis.
In many cases of sciatica, there is no single obvious cause. Anything that irritates the sciatic nerve can produce sciatic pain. However, it is thought that a combination of muscle, joint, and bone strain may lead to sciatica, which is why it is more common in people over 40.
Risk factors for sciatica
Common risk factors for sciatica include:
- Age - due to the deterioration of disks, people in their 30s and 40s have a higher risk of developing sciatica
- Profession - jobs that require lifting heavy loads for long periods
- Sedentary lifestyle - people who sit for long periods and are physically inactive are more likely to develop sciatica, compared with physically active individuals
Although sciatica-like pain can be a problem during pregnancy, sciatica due to a herniated disk is no more likely during pregnancy.
Symptoms of sciatica
The main symptom of sciatica is a shooting pain anywhere along the sciatic nerve; from the lower back, through the buttock, and down the back of either leg (usually, only one leg is affected).
This pain can range from mild soreness to a sharp pain or severe discomfort, and may be aggravated by sitting for long periods.
Other common symptoms of sciatica include:
- Numbness in the leg along the nerve; occasionally, this numbness in one part of the leg may be accompanied by pain in a different part of the leg
- Tingling sensation (pins and needles) in the feet and toes
Diagnosis of sciatica
If the symptoms of sciatica are mild and do not last longer than 4-8 weeks, it is probably acute sciatica, and medical attention is not usually necessary as it tends to resolve itself.
A complete medical history may help speed up the diagnosis. Doctors will also have the individual perform basic exercises (paying close attention to the legs) that stretch the sciatic nerve. A shooting pain down the leg while performing these exercises usually indicates sciatica.
If pain persists for more than 4-8 weeks, imaging tests such as an X-ray or MRI may be necessary to help identify what is compressing the sciatic nerve and causing the symptoms.
Treatments for sciatica
We will look at treatments for acute and chronic sciatica individually:
Most cases of acute sciatica respond well to self-care measures, which may include:
- OTC painkillers - relieve symptoms of pain. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as Ibuprofen, are recommended. Acetaminophen (Tylenol, paracetamol) is recommended for extended use. Not all painkillers are suitable for every patient; be sure to review options with a doctor.
- Exercises such as walking or light stretching.
- Hot or cold compression packs help to reduce pain. It is often helpful to alternate between the two.
Treatment of chronic sciatica usually involves a combination of self-care measures and medical treatment.
- Prescription painkillers - amitriptyline, gabapentin, codeine (a mild opiate-based painkiller), which is often prescribed in combination with paracetamol, and if sciatica symptoms are severe, diazepam
- Physical therapy - teaches exercises to strengthen back muscles and improve flexibility, and how to prevent strain on the back
- Chiropractic treatment - can maneuver the spine to alleviate pressure on the nerves, consequently relieving pain
- Cognitive behavioral therapy (CBT) - helps manage chronic pain by training people to react differently to their pain
Surgery may be an option if symptoms have not responded to other treatments and continue to intensify. Surgical options include:
- Lumbar laminectomy - widening of the spinal cord in the lower back to reduce pressure on the nerves
- Discectomy - partial or entire removal of a herniated disk
Depending on the cause of sciatica, a surgeon will go over the risks and benefits of surgery and be able to suggest a suitable surgical option.
Prevention of sciatica
In some cases, sciatica cannot be prevented. However, there are several lifestyle changes that can reduce the chances of developing it, including:
- Regular exercise - focus on strengthening core muscles (in the abdomen and lower back) necessary for proper posture
- Proper posture - standing and sitting upright, lifting objects correctly, and selecting a mattress and pillow that support the spine
Three exercises for sciatica
In this video, a specialist from Madden Physical Therapy looks at three exercises for the sciatic nerve: