Causes and Risk Factor of Sciatica

Syukriah & Jesslyn =)

Causes
 Spinal Disc Herniation
 Spinal Stenosis
 Piriformis Syndrome
 Spondylolisthesis
 Injury

Spinal Disc Herniation
• Occurs when nucleus pulposus herniates through the annulus fibrosus.
• Usually occurs at the L4/L5 (49.8%) or L5/S1 (46.9%) level.
• Pressing against an adjacent nerve root and compress delicate nerve tissue.
• Older- IV disc start deteriorate à drier à flatter and brittle

Spinal Stenosis
• Narrowing of the spinal canal, thus putting pressure on the spinal cord or on the roots of the branching nerves.
• Nerves can become compressed, either within the spinal cord, or as the spinal nerves exit the spinal cord.
• Narrowing due to bone spurs, vertebral dislocation, inflammation and herniated disc.
• The enlargement of the joints compresses the nerves as they exit from the spinal column.
• The reduced height associated with disc collapse leads to shrinkage of the foraminal canal where the nerves exit.
• The development of spurs on the bones of the vertebral column and these make the space smaller.
Other acquired conditions that may lead to spinal stenosis include rheumatoid arthritis, spinal tumors, Paget's disease, and traumatic damage to the vertebral column. Inherited conditions that lead to spinal stenosis include congenital spinal stenosis, scoliosis

Piriformis Syndrome
 Begins at the front surface of the sacrum (the V-shaped bone between the buttocks at the base of the spine) and passes through the greater sciatic notch to attach to the top of the thigh bone (femur) at its bony prominence called the greater trochanter. The gluteus maximus muscle covers over the piriformis muscle in the buttocks.
 Aids in external rotation of the hip joint.
 The piriformis tendon and sciatic nerve cross each other behind the hip joint, in the deep buttock. Both structures are about one centimeter in diameter.
 Irritation of the sciatic nerve caused by compression of the nerve within the buttock by the piriformis muscle.
 Typically, the pain of the piriformis syndrome is increased by contraction of the piriformis muscle, prolonged sitting, or direct pressure applied to the muscle.


Spondylisthesis
• It is characterized by one vertebra slipping forward over an adjacent vertebra.
• When a vertebra slips and is displaced, spinal nerve root compression occurs.

Most common causes of spondylolisthesis are degenerative and isthmic spondylolisthesis
Degenerative Spondylolisthesis
 Far most common cause of spinal segments slipping on top of each other.
 Aging causes changes to the tissues of the body, including the bones, joints, and ligaments that hold the vertebral column together.
 If the degenerative changes progress to a point when the ligaments and joints cannot hold the proper position of the spinal column, then degenerative spondylolisthesis is the result

Isthmic Spondylisthesis
 Isthmic spondylolisthesis is due to a specific bony defect in the spine called spondylolysis.
 Spondylolysis is a defect in a specific region called the pars interarticularis. A pars defect is most commonly the result of repetitive microtrauma during childhood.
 Some sports are thought to make children more susceptible to developing spondylolysis, including artistic gymnastics(16.96%), rowing (16.88%), throwing sports(26.67%), diving, and football due to the excessive lumbar hyperextension and rotation

Trauma
 Sciatica can result from direct nerve compression caused by external forces to the lumbar or sacral spinal nerve roots.
 Eg : motor vehicle accidents, falling down, football and other sports.
The impact may injure the nerves or occasionally fragments of broken bone may compress the nerves.

Risk Factor

 Age
Age-related changes in the spine are a common cause of sciatica. The discs in your back begin to lose water content and degenerate, increasing the risk of disc problems and back pain, especially after age 40. Most people who develop herniated disks are in their 30s and 40s.

 Occupation.
Work that requires the following motions puts additional stress on the back:
- Heavy lifting
- Bending or twisting
- Exposure to vibrations, such as riding in a car or operating heavy machinery
*Back pain was responsible for around 60% of cases of people missing work due to pain involving the upper body.

 Improper Lifting Techniques
Lifting objects using your back muscles instead of the stronger muscles in your legs increases your risk of back injury.

 Diabetes
This condition, which affects the way your body uses blood sugar, increases your risk of nerve damage. Extra pounds can increase pressure on the spinal muscles and disks.

 Walkers and runners
- This is likely due to the repeated contraction of a muscle in the hip (PM), a key muscle used in walking and running. PM becomes tight and cause irritation to the sciatic nerve.
- A study conducted in Finland and published in Spine Journal (2002) showed that walking is associated with the onset of sciatica symptoms, while jogging is associated with a continuation of symptoms

 Participating in Strenuous or Contact Sports
Injuries from contact sports or falls can result in back pain

 Cigarette Smoking
Smoking may contribute to degeneration of the discs in the spine

 Prolonged sitting. People who sit for prolonged periods or have a sedentary lifestyle are more likely to develop sciatica than active people are.

 Sedentary Job or Lifestyle
Muscles that support the back can become weak with lack of exercise

 Pregnancy
Pregnant women are prone to back pain due to a shifting of abdominal organs, the forward redistribution of body weight, and the loosening of ligaments in the pelvic area as the body prepares for delivery. Tall women are at higher risk than short women