The bones of the spine are called vertebrae, and they are separated by small round, quarter-sized discs. Called intervertebral discs, these cushioning spinal components have a tough outer layer (annulus) that surrounds a gel-filled, watery nucleus. A herniated disc, also called a ruptured or slipped disc, is when the inner disc material pushes out the annulus and into the spinal canal.
What is the purpose of intervertebral discs?
The discs of the spine act as shock absorbers for the vertebrae (spinal bones). They allow for spinal motion and flexibility, and prevent bones from rubbing together.
What causes a herniated disc?
With a herniated disc, a fragment of the nucleus pushes out of the annulus through a crack or tear in the tough, outer disc layers. Discs often herniated in early stages of degenerative disc disease (DDD). A single, excessive strain or traumatic injury can cause a disc to herniate. However, with age and wear-and-tear, the ligaments that hold discs in place begin to weaken. With degenerative progression, twisting or straining can lead to nucleus rupture through the annulus.
Who is at risk for a herniated disc?
Anyone can suffer a herniated disc, and they most often occur in the lower spine. Research shows that herniated discs are more common in men, people who perform heavy labor duties, and those with a predisposition.
What are the symptoms of a herniated disc?
The symptoms of a herniated disc vary depending on the size of the herniation and location of injury. When a herniated disc does not impinge on nerves, most people report only mild back pain. When the nucleus material puts pressure on one or more spinal nerves, it can produce pain that radiates into an arm or leg, as well as weakness, and numbness of the extremity. With a lower back (lumbar spine) herniated disc, pressure often affects the sciatic nerve, which supplies each of the lower legs. This pressure can produce an electric shock-like pain that is more severe with walking or standing.
How is a herniated disc diagnosed?
Diagnosis of a herniated disc is made based on the patient’s medical history, a physical examination, and diagnostic testing. Tests used to assess the spine include:
- X-rays – Use of radiation to produce a picture of the spine to assess alignment of joints and bony structures.
- Computed tomography (CT) scan – A diagnostic image created by computer technology. This scan can show the shape and size of the spinal canal, as well as spinal structures and components.
- Magnetic resonance imaging (MRI) scan – This test produces 3-D images of spinal structures using computer technology and magnets.
How is a herniated disc treated?
- Medications – For pain relief, the doctor can prescribe a combination of medications. These include narcotic analgesics, nonsteroidal anti-inflammatory drugs (NSAIDs), anticonvulsants, and antidepressants.
- Epidural steroid injection (ESI) – Using x-ray guidance, the doctor can inject the space around the spinal cord with a steroid agent and anesthetic. This offers pain relief for up to 3 months.
- Physical therapy – The therapist will perform an in-depth assessment to design a treatment plan. Therapy can include massage, pelvic traction, heat/ice treatments, ultrasound, and electrical muscle stimulation. Stretching and strengthening exercises are used to improve spinal function.
- Lumbar laminotomy – This surgery is used to relieve leg pain and sciatica. The surgeon removes a portion of the lamina (vertebra component) as well as the herniated disc.
- Spinal fusion – Often performed along with a laminotomy, this procedure involves fusing vertebra together to provide spinal support.
How common is a herniated disc?
According to a recent study, symptomatic herniated lumbar disc affects around 2% of the general population. The highest prevalence is among persons aged 30 to 50 years. Men are affected twice as often as women (2:1 ratio), and 95% of herniated discs occur in the lower spine. Thoracic (middle spine) and cervical (neck) disc herniates are more common among persons age 55 years and older.
Jordon J, Konstantinou K, & O’Dowd J (2009). Herniated lumbar disc. BMJ Clin Evid, 1118.