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 pain is typically felt below the knee, which differentiates it from back pain.
Sciatica may occur in people in their 30s and 40s as a result of strenuous physical activity like sports or heavy lifting, or in older people as a result of ageing and degeneration of the spine. It is estimated that up to 40 per cent of the New Zealand population will experience sciatica at some point in their lives.
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.
Vertebrae are the stacked individual interlocking bones (vertebra) that form the spine (vertebral column). Another cause of sciatica is spondylolisthesis, which is when a vertebra slips out of position causing pressure on 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 that 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
- Diabetes, which increases the risk of nerve damage
- Being overweight, which increases stress on the spine
- Jobs that involve twisting of the back or carrying heavy loads
- Sitting for prolonged 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 sciatica 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.
Sciatic pain and other 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.
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 vertebrae 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.
Pain relief and treatment
The primary goal of initial treatment is the relief of pain. Treatment and relief options for sciatica include:
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.
Pain relieving medications such as paracetamol and ibuprofen 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 (e.g., pethidine, morphine) may be necessary. Other medications that may be used are low-dose anti-depressants to reduce nerve stimulation, and corticosteroid 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.
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.
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 an object, 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 correct seating posture. A lumber roll or contoured cushion can help to provide lower back support
- Quit smoking
- Maintain a healthy body weight.
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Mayo Clinic (2022). Sciatica (Web Page). Rochester, MN: Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/diseases-conditions/sciatica/symptoms-causes/syc-20377435. [Accessed: 18/11/22]
NHS (2020). Sciatica (Web Page). Redditch: National Health Service (NHS)
England. https://www.nhs.uk/conditions/sciatica/ [Accessed: 18/11/12]
O’Toole, M.T. (Ed.) (2017). Sciatica. Mosby’s Dictionary of Medicine, Nursing & Health Professions (10th ed.). St Louis, MI: Elsevier.
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Last Reviewed: November 2022