DEAR DOCTOR K >> I suffer from sciatica, which has caused a lot of pain over the past six month. My doctor has recommended epidural injections, but I hear that they have been disproven. Can you help me sort this out?
DEAR READER >> Here's an answer I'm sure you'll find satisfying — It depends! It depends on what's causing the sciatica, and on which studies you believe.
Sciatica is a persistent aching or burning pain felt along the sciatic nerve. The two sciatic nerves are the longest nerves in the body. They run from the lower back down through the buttocks and into each of the lower legs. The pain of sciatica can be severe. It can go away on its own, but for many people, sciatica is a chronic condition that keeps coming back.
Sciatica occurs when the sciatic nerve is pinched, irritated or injured. Inflammation, arthritis or a displaced disk in the lower spine is often to blame.
Doctors commonly treat sciatica with epidural injections into the spine. (The word "epidural" refers to a particular area in the spine.) The injections contain a steroid, which reduces inflammation. The injections can also contain a long-lasting painkiller.
The different causes of sciatica may be one reason that studies come to different conclusions. If a person's sciatica is caused by inflammation rather than by arthritis, it may be more successfully treated by steroids — since the main effect of steroids is to reduce inflammation.
The best kind of study for any treatment procedure, like an injection of medicines, is a randomized trial that includes a sham procedure. In this kind of study, every person gets an injection, but only some people, chosen at random, get an injection of the real medicine; the rest get just a placebo injected or nothing injected (a sham procedure).
Unfortunately, different randomized trials have come to different conclusions. What doctors do in such a situation is to pool the results of all the different studies to see if they collectively come to a clear conclusion.
Probably the best such study was published in 2012. These were patients like you — as best I can tell from your letter. They all had been suffering from sciatica that was not going away with conservative treatment: exercises and mild painkillers. The conclusion of the study was that the epidural injections produced a small improvement in leg pain over the next three months. However, by one year later, there was no clear benefit.
Given the severity of your sciatica pain, it might be worth trying an epidural injection.
Talk to your doctor about whether simpler treatments such as exercises, physical therapy, compresses, painkilling medicines, chiropractic manipulation, massage, yoga or acupuncture might be worth considering.
Dr. Komaroff is a physician and professor at Harvard Medical School.