Sciatica

What is sciatica?

Sciatica is pain resulting from irritation of the sciatic nerve. The sciatic nerve is the largest nerve in the body and begins from nerve roots in the spinal cord in the low back and extends through the buttock area to send nerve endings down the lower limb. Sciatica pain is typically felt from the low back to behind the thigh and radiating down below the knee.

What are the causes?

While sciatica is most commonly a result of a disc herniation (disc prolapse) directly pressing on the nerve, any cause of irritation or inflammation of this nerve can reproduce the symptoms of sciatica. These cause include irritation of the nerve from adjacent bone, tumours, muscle, internal bleeding, infections or injury.

What are the symptoms?

In sciatica, the pain travels below the knee, and may involve the foot. There may be numbness or weakness of the lower leg muscles. The order in which the symptoms appear may vary. Sometimes, the back pain comes before the sciatica, and sometimes it follows.
One or more of the following sensations may occur:

• Pain in the buttocks and/or leg that is worse when sitting
  
• Burning or tingling in the leg
  
• Weakness, numbness or difficulty in moving the leg or foot
  
• A constant pain on one side of the buttocks
  
• A shooting pain that makes it difficult to stand up

How is it diagnosed?

A physical examination may help pinpoint the irritated nerve root. The doctor may ask you to squat and rise, walk on the heels and toes or perform a straight leg raising test. Most cases of sciatica affect the L5 or S1 nerve roots. Later, X-rays and other specialized imaging tools such as MRI (magnetic resonance imaging) may confirm which nerve roots are affected. These test show the soft tissue structures in the spine, as well as the bones, and will show whether a nerve is being squeezed by a disc, or whether something else is causing irritation of the nerve.

What is the treatment?

Treatment for sciatica is aimed at helping to manage the pain without long-term use of medications. At least a few days of bed rest is needed for the inflammation to go away. Other treatments for sciatica include addressing the underlying cause, medications to relieve pain and inflammation and relax muscles, and physical therapy.  

Nonsteroidal anti-inflammatory medications (NSAIDs) such as ibuprofen, aspirin or muscle relaxants may help. It might help to apply gentle heat on the painful muscles. It is necessary to find positions that are comfortable and to be as active as possible. Movement helps to reduce inflammation. Most of the time, the condition will get better within a few weeks. Physical therapy with stretching exercises be started as soon as possible.

If the pain is severe and very disabling and cannot be controlled with simple painkillers and/or anti-inflammatory medication, the doctor may suggest an epidural injection, which is an injection into the spine, which soothes the nerves that are causing the pain.

Surgery is necessary only if after 3 months or more of treatment the disabling leg pain persists. A part of the herniated disc may be removed relieve the pressure on the nerve. The surgery may be done under local, spinal or general anaesthesia. Avoid driving, excessive sitting, lifting or bending forward for at least a month after surgery. The doctor may suggest some exercises to strengthen the back.