When you or a loved one is living with sciatica, learning the causes of sciatica is a valuable tool. When you understand the causes, the symptoms, and the treatment options, you will be able to make informed decisions regarding your treatment.
Even though we talk about having sciatica, sciatica is not a disease or a diagnosis, sciatica is only a "symptom" of the real problem.
Sciatica is caused by pressure on, or irritation of the sciatic nerve.
Descriptions of the pain vary depending on what is causing the problem, exactly where the problem lies, and how severe the problem is.
"Sciatica is caused by pressure"
Some people complain of a needles and pins sensation in the back of the thigh. Some will report a severe ache, "like a toothache", deep in their buttock. Others will swear up and down that the problem is in their hip. Along with these more severe symptoms, many people will have numbness in the calf or foot.
The sciatic nerve is formed by the joining of five nerve roots after they exit the spinal canal. It then runs across the posterior pelvis, and along the back of the thigh. Near the knee it divides into the peroneal nerve, and the tibial nerve, which in turn divide into smaller nerves further along the leg.
"felt anywhere along the course of these nerves"
Problems, or the causes of sciatica, may develop anywhere along the length of these nerves. Signs and symptoms of sciatica pain may be felt anywhere along the course of these nerves, and there is often very little relationship between where the nerve is being irritated and where you feel the pain or symptoms.
"The most common causes..."
The most common causes of sciatica are a bulging or herniated disc, Lumbar Spinal Stenosis, spondylolisthesis, piriformis syndrome, trauma, and pregnancy. Less common causes of sciatica include infections, tumors, and other disease processes may occur within the body of the nerve itself.
A bulging or herniated disc can cause problems by putting pressure on nerve root, as it exits the spinal canal. The spinal vertebrae are separated by the intervertebral discs. These discs are formed by a ring of tough ligament around the outside (called the annulus), with a center made up of softer material (called the nucleus pulposis). With the wear and tear of just living your life, the annulus may develop a weak spot and begin to bulge, or it may herniate forcing the nucleus pulposis out of the disc. If this occurs at a location that places pressure on a nerve it can cause sciatica. The severity of the sciatica will depend on how tight the nerve is being squeezed.
Spinal Stenosis occurs when the lumbar spinal canal becomes narrowed, leaving little or no space for the nerves. This is generally found in people over 50 years of age, and it is usually caused by a combination of three different factors.
(1) There are large ligaments that run down the inside of the spinal canal, and with a lifetime of lifting and bending, they get big and overgrown, taking up space the for the nerves.
(2) The little joints in your back, called facet joints can get arthritis. As they get big and overgrown with bone spurs, like any arthritic joint, they can grow into the space for the nerves.
(3) If you have a bulging disc, bulging into the spinal canal, this can also take up the space for the nerves. When these factors combine to put pressure on a nerve symptoms may be felt anywhere along the buttock, thigh, and calf.
Spondylolisthesis occurs when one vertebra slips forward on another. This slippage may be mobile, causing symptoms only with activity, or solid causing symptoms that are constant. Spondylolisthesis causes symptoms because the small passageway where the nerves exit the spinal canal, is formed with the top half of the hole with the top vertebra, and the bottom half of the hole with the bottom vertebra. When the top half of the hole slips forward on the bottom half, the nerve can get pinched, often causing symptoms in the buttock, thigh, or leg.
Piriformis Syndrome occurs when the sciatic nerve is compressed as it passes under or through the piriformis muscle in the buttock. This condition is difficult to diagnose because there are no imaging or other studies that will clearly define the problem. Often Piriformis Syndrome will be the diagnosis when all of the other possibilities have been eliminated.
Trauma to the nerve roots that makeup the sciatic nerve or to the sciatic nerve itself, may cause sciatic pain in the buttock or thigh, or even into the calf or foot, depending on where the injury occurs. A car or a motorcycle accident may cause spinal fractures damaging the nerve roots exiting the spinal canal, a fall landing on your buttock may bruise the sciatic nerve, or the retractors used during hip replacement surgery may stretch the sciatic nerve. Any of these and many other types of mishaps may cause sciatica symptoms.
Sciatica in pregnancy may be associated with low back pain, and it is generally treated very conservatively for obvious reasons. Sciatica stretches and sciatica exercises for treatment in pregnancy are usually safe, but they should be discussed with your obstetrician.
Although these are not causes of sciatica, anytime you are dealing with sciatica you must be alert for any signs or symptoms of cauda equina syndrome.
"can cause permanent injury and disability"
If you begin having any problems with your bowels or bladder or if you are having any progressive weakness in your lower extremities you need to be seen by a doctor immediately. If your doctor cannot see you right away, you should go to an emergency room for evaluation. You may be developing cauda equina syndrome, which can cause permanent injury and disability if not treated immediately.
Other Causes do Exist
These are the most common causes of sciatica, but others do exist. The severity of the symptoms with any of these can range from only annoying or barely noticeable to very severe and incapacitating.
If your symptoms are more than just bothersome, you need to be evaluated by a medical professional to find out about the causes of sciatica and what can be done.