Sciatica - symptoms, pain relief, treatment

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Sciatica is pain caused by problems with the sciatic nerve, which runs from the lower back, down the back of each leg to the feet.

Sciatica may occur in people in their 30s and 40s as a result of strenuous physical activity like sports or heavy lifting, or older people as a result of ageing and degeneration of the spine. It is estimated that up to 40% of the New Zealand population will experience sciatica at some point in their lives.

Causes

The sciatic nerve is the largest and longest nerve in the body. It originates in the lower spine, branches into the pelvis, then travels through the buttocks, down the back of each leg.

Sciatic pain occurs when there is pressure on, or damage to, the sciatic nerve. The most common cause is a herniated disc (also known as slipped disc or disc prolapse). This occurs when one of the soft, gel-filled discs between the vertebrae of the spine bulges or ruptures, compressing and/or irritating the sciatic nerve.

Muscle spasms can also cause sciatica by compressing the sciatic nerve as it travels through the muscles. Less common causes of sciatica include infection, pelvic injury or fracture, and tumours.

In older age groups, sciatica may occur as the result of conditions caused by spinal degeneration, such as spinal stenosis. This is where the pathways through which the sciatic nerve travels are narrowed, causing compression and/or irritation of the nerve. Age-related outgrowths of bone (bone spurs) on the vertebrae can also compress the sciatic nerve.

While any injury or process which causes compression of the sciatic nerve can cause sciatic pain, in many cases there may be no specific cause identified for the sciatic pain.

Factors that increase the likelihood of developing sciatica include:

Older age
Pregnancy
Being overweight
Smoking
Jobs that involve twisting of the back or carrying heavy loads
Sitting for long periods.

Signs and symptoms

The pain caused by sciatica can range from being mild to very severe. It can occur suddenly or have a gradual onset. Sciatic pain is commonly described as a cramp-like pain that can be burning or sharp in nature. It may be associated with sensations such as pins and needles, tingling, numbness and weakness.

Sciatic pain is typically felt in the lower back and hip and radiates down the back of one leg. The characteristic that distinguishes it from other types of back pain is that the pain travels below the knee. The pain may be aggravated by specific actions, such as sneezing, coughing, lifting or sitting.

Pain and symptoms are usually most severe in the early stages of the condition, when compression and inflammation of the sciatic nerve are at their greatest. It is common for the pain to gradually reduce until it resolves completely - usually within four to eight weeks.

In rare cases compression of the sciatic nerve can be so severe that there is progressive weakness in the legs and/or loss of bowel and bladder function. If these symptoms are experienced, medical attention should be sought immediately as they can signal severe nerve damage.

Diagnosis

To make a diagnosis a doctor will ask about the nature and duration of the symptoms, and what action or event led to the onset of the pain. They will assess neurological function by checking the strength, sensation and reflexes in the legs. If loss of bowel or bladder control has been experienced, the doctor may perform a rectal examination to check for loss of sensation and muscle tone.

If the sciatic pain persists for a number of weeks, x-rays may be taken to assess any changes to the bones of the spine and pelvis and to rule out other causes for the pain such as tumours and infection. A CT (computerised tomography) scan or MRI (magnetic resonance imaging) may be recommended in some cases in order to assess the nerves, discs and spine in more detail.

Electromyography (EMG) that may be used to test for nerve compression, such as that caused by a herniated disc or spinal stenosis.

Pain relief and treatment

The primary goal of initial treatment is the relief of pain. Treatment and relief options for sciatica include:

Moderate activity
Bed rest had traditionally been recommended in the treatment of sciatica but this is no longer the case. Research has indicated that bed rest does not tend to speed recovery and may in fact hinder it. It is now recommended that heavy physical activity should be avoided, but moderate activity should be maintained. It is thought that maintaining activity assists with overall recovery by helping to reduce inflammation.

Medications
Pain relieving medications such as paracetamol and ipuprofen are commonly used to treat sciatic pain. In cases where muscle spasms are thought to be the cause, muscle relaxant medications may be recommended. When pain is severe the use of opioids (eg: pethidine, morphine) may be necessary. Other medications that may be used are low-dose anti-depressants to reduce nerve stimulation, and cortisone injections near the spine to reduce pain and inflammation.

Physiotherapy and physical therapy
Manipulation and specific exercises may be helpful in the treatment of the condition. Once the pain has improved, a physical therapist may design a rehabilitation programme to prevent future injury.

Home care and alternative treatments
Applying cold or hot packs to the painful area may help with pain relief, as might stretching exercises for the lower back. Some people may find relief of symptoms through osteopathy, chiropractic, massage or acupuncture.

Surgery
While most cases of sciatica resolve within 12 weeks, surgery may need to be considered in severe, prolonged cases where non-surgical treatment has been unsuccessful or where rapid pain relief and mobility improvement is required. Surgery aims to relieve the pressure on the sciatic nerve. This may involve removal of abnormal disc material (discectomy) or bone spurs. All other forms of treatment should be exhausted before surgery is considered.

Prevention

While back pain due to sciatica, and other causes, is common, there are a number of measures that can help to prevent it occurring or recurring:

Maintain correct posture when standing, walking and sitting
Undertake exercise that maintains fitness, strength and flexibility in the abdominal and spinal muscles
Practice safe lifting techniques. When lifting bend the knees, keep the back straight and hold the object close to your body. By doing this, the strain is taken by the hips and legs, rather than the lower back
Ensure that your back is well supported when seated. Use chairs that provide good back support and are designed to provide a good seating posture. A lumber roll or contoured cushion can help to provide lower back support
Quit smoking
Maintain a healthy body weight.

References

Pubmed Health (2018) Sciatica (Web Page). Bethesda, MD: US National Library of Medicine. https://medlineplus.gov/ency/article/000686.htm. [Accessed: 19/06/19]
Mayo Clinic (2018). Sciatica (Web Page). Rochester, NY: Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/diseases-conditions/sciatica/symptoms-causes/syc-20377435. [Accessed: 19/06/19]
O’Toole, M.T. (Ed.) (2017). Sciatica. Mosby’s Dictionary of Medicine, Nursing & Health Professions (10th ed.). St Louis, MI: Elsevier.Ropper, A.H., Zafonte, R.D. (2015). Sciatica. N Engl J Med. 2015 Mar 26;372(13):1240-8

Last Reviewed – June 2019