Causes of Sciatica

Sciatica pain is caused by irritation and inflammation of the sciatic nerve, a large nerve that branches off the spinal cord. The sciatic nerve is the largest nerve in the body, about the diameter of a finger. Its nerve fibers begin at the 4^th and 5^th lumbar vertebra (L4, L5) and the first few segments of the sacrum. It runs vertically down the back of the thigh, behind the knee, branching into the calf (hamstring muscle) and further down into the heel. The pain usually affects one side of the body, starting in the buttocks and gradually radiating down the back or side of the thigh. It may radiate down the leg below the knee and it may even reach the heel. It is described as:

• Burning
• Sharp
• Dull ache
• Tingling or Numbness
• Continuous or intermittent pain

These painful symptoms may progress to severe pain in the heel or foot along with numbness, tingling and progressive weakness in the affected limb. Additional symptoms are:

• Pain increases with walking
• Pain worsens with prolonged sitting
• Pain may be worse when trying to stand from a low sitting position
• Pain worsens when bending backward, coughing, sneezing, or straining

Several different types of spinal disorders can cause a compression of the spinal nerve, resulting in the pain and inflammation of sciatica. The most common causes are:

• Herniated Disc
• Bulging Disc
• Degenerative Disc Disease
• Lumbar Spinal Stenosis
• Spondylolisthesis
• Piriformis Syndrome
• Spinal Tumor
• Trauma caused by fall, car accident, or sports injury

The most important step in treating sciatica is to determine what is causing the compression of the sciatic nerve roots. Because there are many causes, symptoms and treatment vary from patient to patient. Diagnostic tests and examinations must be complete and thorough. Imaging methods such as MR neurography has been effective in diagnosing 95% of severe sciatica patients. This is a modified MRI technique which provides improved pictures of the spinal nerves and the effects of compression on these nerves. Since some reports show that 15% of sciatica sufferers have disc related problems, this technique is a helpful diagnostic tool. The implementation of an effective treatment plan will be determined by a diagnosis of the cause of the sciatica pain.