Back pain accompanied by pain radiating down one or both legs is sciatica, right? While that’s often the case, several other back problems can be confused for highly common sciatic type pain, according to Kaliq Chang, MD, of Atlantic Spine Center.
First, what is sciatica? It’s not a condition in itself, but actually a term used to describe symptoms caused by compression of the sciatic nerve, explains Dr. Chang who is an interventional pain management specialist. All sciatica cases have one thing in common: The pain begins in nerve roots located on either side of the lower spine, but radiates down the spine in a way that can be much worse than back pain alone.
“This radiating pain can worsen while sitting or it can show up as a sharp, constant pain on the back of the leg that hinders standing or walking,” Dr. Chang says. “Some cases of sciatica result in numbness or tingling down one leg, and severe cases, which are rare, can include weakness or loss of motor function in the leg or foot.”
Causes of sciatica:
When the sciatic nerve is compressed, the resulting pain is due to one of several underlying common conditions, Dr. Chang says. These include:
- Bulging spinal disc
- Herniated spinal disc
- Spinal stenosis (a narrowing of the canal surrounding the spinal cord)
- Scar tissue
- Spinal bone spurs
“Essentially, any condition coming from the lower back that’s close enough to the sciatic nerve can prompt sciatica,” he says. “Symptom severity, however, is highly variable. For one patient, the pain is mild, while for another, it may stop them in their tracks.”
Conditions mimicking sciatica and how doctors can tell the difference:
Several causes of leg pain certainly feel like sciatica but aren’t because they’re due to other conditions. These include:
- Piriformis syndrome, which happens when the piriformis muscle in the buttocks, irritates the sciatic nerve, causing radiating pain down the leg. “Although piriformis syndrome feels extremely similar to sciatica, it differs because the nerve irritation doesn’t stem from the lower back,” Dr. Chang explains.
- Spinal joint problems such as arthritis. These joint problems can result in “referred” pain from the affected joint into the leg that feels like sciatica but isn’t, Dr. Chang says.
- Sacroiliac joint dysfunction, which occurs when the sacroiliac joint – which connects the bottom of the spine to the pelvis – moves too little or too much. “The resulting pain can radiate down the legs like sciatica,” Dr. Chang says.
While these variations may seem small, they can mean big differences in how a back condition is treated. How can doctors correctly diagnose sciatica and differentiate it from similar conditions? Fortunately, there’s a test that accomplishes this known as the straight leg raise, Dr. Chang says.
For the test, patients are asked to lay flat on their back with their legs extended straight in front of them. The physician slowly raises each leg, noting the elevation the patient’s pain begins. The test helps doctors determine where the sciatic nerve is being compressed and can also help determine the cause.
“X-rays or imaging scans such as CTs or MRIs may also be used to pinpoint sciatica’s cause after the straight leg raise,” Dr. Chang explains. “The key thing is to see a physician for a correct diagnosis. Depending on the true cause of your pain, prompt treatment may be crucial.”