Radiating Leg Pain / numbness

Sciatica is the symptom of shooting or radiating nerve pain that generally begins in the lower back or buttock(s) and spreads down the leg(s). Whilst the pain often spreads down the back of the thigh to the lower leg and can reach the foot, sometimes the pain can radiate to the outer part of the thigh and or the front of the thigh. Some patients describe pain in the lower leg without pain in the thigh. Occasionally the pain radiates into the groin.

Sciatica is often associated with numbness or sensory disturbance either in a similar distribution of the pain or beyond the pain and commonly into the foot. Sciatica can be associated with a feeling of weakness in the leg or foot or even big toe. Weakness should be taken seriously, and a clinic appointment arranged.

This symptom was originally named after the largest nerve in the body the Sciatic nerve which travels through the buttock the to the back of the thighs. However, the pain is usually caused by pressure on one or more of the nerve roots in the lower back due to a herniated disc, bony arthritic spurs or rarely muscle inflammation and not  commonly due to irritation of the Sciatic nerve itself.

Seek medical help immediately if:

• You have real leg weakness, numbness in the genital area, or loss of bladder or bowel function. These are signs of a condition called cauda equina syndrome.
• If you have a problem called "foot drop," which is when you cannot seem to hold your foot up. You might notice this especially while walking.
• Back or leg pain along with a fever or other symptoms that worry you.

What are the causes of Sciatica?

• Herniated Disc / Disc Prolapse: A part of the jelly-like centre of the spinal disc can bulge or rupture through a weak area in the outer disc wall and compress the adjacent nerves.
• Osteoarthritis: As discs naturally age, they dry out and shrink. Small tears in the disc wall develop and can be painful. The facet joints enlarge and ligaments thicken. Bone spurs can also form. These spurs can pinch the nerves and cause Sciatica.
• Stenosis: The processes described above can result in a general narrowing of the central canal in the spine which can compress the spinal nerves and cause the pain
• Spondylolisthesis: A weakness or old stress fracture in a narrow section of bone (the Pars) of the lumbar spine can allow a vertebra to slip out of position and pinch the nerves.
• Piriformis syndrome: Tightening or spasm of the piriformis muscle can sometimes result in radiating leg pain which mimics the pain of a slipped disc.
• Trauma: A sports injury or fall can fracture the spine or tear a muscle and damage nerves.
• Referred Pain: Leg pain can also be due to a problem in the hip or sacroiliac joint. This type of pain is termed “Referred Pain”.

How is a diagnosis made?

A careful medical exam will attempt to determine the type and cause of your spine problem and the treatment options. A diagnostic evaluation includes a medical history and physical exam. Often imaging scans (e.g., x-ray, CT, MRI) and tests to check muscle strength and reflexes are used.