Severe sciatica

The short version: sciatica usually resolves on its own, and the evidence for most interventions is thin, conflicted, or based on studies that compare the wrong groups.

Severe sciatica is a symptom, not a diagnosis. The underlying cause is usually a herniated disc or spinal stenosis compressing a nerve root. The first question is whether you need urgent evaluation. Red flags that require immediate attention include progressive leg weakness, numbness in the saddle area, loss of bladder or bowel control, and a history of cancer with new back pain [4, 5]. In emergency departments, about 2 in 100 people with back pain have cauda equina syndrome or radiculopathy with weakness, and about 1 in 100 have a spinal infection or tumor [4]. A history of cancer raises the probability of spinal cancer substantially [4]. If you have none of these, the odds of a dangerous cause are low.

The natural history is your friend. About 75 to 90 out of 100 people with acute low back pain recover within six weeks with no specific treatment [6]. Imaging often finds things that look abnormal but mean nothing. MRI shows disc bulges or nerve root compression in 20 out of 100 people who have no pain at all [6]. A large randomized trial found that MRI findings at one year did not distinguish people who got better from those who did not [3]. Routine MRI for sciatica without red flags leads to more surgery, not better outcomes.

The evidence for treatments is weaker than most doctors admit. Epidural steroid injections reduce pain in the short term, but the studies are small and funded by the procedure itself. One study of 18 people found that women reported more pain relief than men after the injection, but there was no unvaccinated—sorry, no untreated control group [2]. The study compared the injected to the injected. Spinal manipulation showed a short-term change in muscle activity in a 27-person trial, but the effect was small and the follow-up was a single session [1]. Surgery for a herniated disc speeds recovery in the first few months but by one year the results are the same as for people who did not have surgery [3].

My call: for severe sciatica without red flags, the best evidence supports waiting, staying active, and avoiding bed rest. Imaging and injections are overused and understudied. Surgery is a last resort for persistent weakness or unrelenting pain after six to eight weeks. Confidence: moderate.