If you’ve been told that you have sciatica, it is not a disease itself but a symptom of an underlying condition. Sciatica describes leg pain, often accompanied by numbness, weakness or tingling, that starts in the lower back and runs down the buttocks and sciatic nerve behind each leg. It is very important to find out the underlying diagnosis of what’s causing your sciatica so that you can get the appropriate treatment. NYC Spine Surgeon Dr. Fischer at NYU Langone Medical Center in New York City can provide the correct diagnosis and get you started on the road to recovery. Some of the most common root causes of sciatica are described below.
Lumbar herniated disc
Each of the discs along your vertebrae is filled with soft material on the inside. If that material leaks out though the outer core of the disc, it’s called a herniated disc. Other popular names for this condition are ruptured disc, slipped disc, protruding disc, bulging disc, or pinched nerve. No matter what it’s called, the result is that the disc pinches or irritates the nerve root and causes discomfort.
Degenerative disc disease
It is normal for discs along the spine to degenerate somewhat with age, but sometimes it is more than the normal degree of deterioration. One or more discs in this condition can irritate a nerve root and lead to sciatica. In some cases, bone spurs also develop and press against nerves.
Lumbar spinal stenosis
Most common in adults over age 60, lumbar spinal stenosis can occur naturally with age. It often results in a herniated disc pressuring nerve roots, enlarged joints, or narrowing of the spinal canal. Any of these conditions can cause sciatica. Lumbar spinal stenosis is also linked to spinal arthritis, also a contributor to sciatica discomfort.
Sacroiliac joint dysfunction
If the sacroiliac joint at the bottom of the spine becomes irritated, it can mimic sciatic pain. The sacroiliac joint lays right under the L5 nerve, making it a common cause for pain when that nerve becomes irritated.
When a minor stress fracture of a vertebrae causes it to move forward onto another vertebrae, it is called isthmic spondylolisthesis. The nerve can become pinched when there is a fracture, a collapse of disc space, and a vertebrae that slips onto another one. This combination may produce sciatica.
The piriformis is a muscle in the buttock that runs on top of the sciatic nerve. If the piriformis muscle pinches a nerve root or otherwise irritates the nerve, it may cause pain similar to sciatica. Although it’s not considered one of the clinical definitions of sciatica, the leg pain feels very similar to it.
In addition to the most common reasons for sciatica above, various other conditions can be the culprit for sciatica. Dr. Fischer sometimes diagnoses sciatica related to these other reasons:
- Pregnancy – body changes and weight shifts may cause sciatica
- Muscle strain – lower back muscle strains or spasms can pressure nerve roots and cause sciatica
- Fracture – fractures in the lumbar vertebra, often due to a fall or car accident, may cause sciatica
- Scar tissue – scar tissue pressing on a lumbar nerve root can produce sciatica
- Ankylosing spondylitis – chronic spinal inflammation typically causes pain in the sacroiliac joints, but may later progress to sciatica
- Infection – rarely, a lower back infection can damage the nerve root and cause sciatica
- Spinal tumor – also rare, a spinal tumor may press a nerve root and produce sciatica symptoms