Sciatica

What is actually happening

The sciatic nerve is formed from nerve roots leaving the lower spine at L4 through S3. Sciatica is what you feel when one of those roots is compressed or chemically irritated — most often by a herniated disc pressing against it, sometimes by narrowing of the canal or the bony opening the nerve travels through.

The pain is worse than the back pain that comes with it, and it follows a strip down the leg rather than aching everywhere. That pattern is the diagnosis. Where in the leg it travels tells us which nerve root is involved before we look at a single image.

First-line care

Most sciatica improves. Roughly three out of four people are substantially better within six to twelve weeks with time, activity modification, anti-inflammatories and physical therapy. Bed rest makes it worse; gentle, frequent movement makes it better.

We start conservatively when the picture allows it. Where we intervene sooner is when the pain is severe enough to stop you sleeping or working, when it has already dragged on for six weeks without change, or when there is measurable weakness.

Epidural steroid injection for sciatica

The most effective interventional treatment is an epidural steroid injection placed at the affected nerve root under live X-ray guidance. It reduces the inflammation around the nerve, which is what most of the burning pain comes from.

Relief usually starts within two to seven days and commonly lasts three to six months — often long enough for the disc herniation itself to shrink, which most do over time. Some patients need only one injection, ever.

Red flags — do not wait

• Loss of bladder or bowel control, or numbness in the groin — emergency room now
• Rapidly worsening leg weakness or a foot that drags
• Sciatica on both legs at once
• Fever, chills or unexplained weight loss with the pain