Sciatica: Causes, Tests, and Non-Surgical Options

Sciatica is the name given to pain that radiates from the lower back down one leg, usually following the path of the sciatic nerve. It is one of the most distinctive symptoms in orthopedic practice and one of the most distressing for patients — the pain is often sharp, electric, and disrupts sleep, work, and movement. The good news is that the great majority of sciatica resolves without surgery. This article explains what sciatica actually is, the most common causes, the role of imaging and tests, and the treatment options from conservative to surgical.

What sciatica is — and isn't

Sciatica is a symptom, not a diagnosis. It describes leg pain caused by irritation of a lumbar or sacral nerve root in the spine. The classic presentation is sharp pain shooting from the lower back or buttock down the back or side of the thigh, past the knee, sometimes to the foot. Tingling, numbness, and weakness in a specific pattern follow the affected nerve root.

Leg pain that doesn’t follow this pattern — that stays in the buttock or thigh without going past the knee, that is felt all over the leg, or that is worse at night without movement — is often something else: hip pathology, piriformis syndrome, or a vascular condition.

What causes sciatica

The most common causes:

• Lumbar disc herniation — a fragment of the intervertebral disc bulges out and presses on the nerve root. Most common cause in patients under 50.
• Spinal stenosis — narrowing of the spinal canal or nerve root canal. More common in patients over 60.
• Spondylolisthesis — slipping of one vertebra on another, compressing the nerve.
• Less commonly — infection, tumour, or bony spurs.

The examination

A careful examination tells most of the story. The straight-leg raise test (lifting the affected leg with the patient supine to reproduce the leg pain) is highly suggestive of a disc-related cause. Reflex testing, muscle strength testing in specific patterns (foot drop suggests L5; weakness pushing off the foot suggests S1), and sensory testing localise the affected nerve root. Specific test findings often predict the level of the disc problem within one segment.

When to image

MRI of the lumbar spine is the imaging test of choice for sciatica that is severe, persistent beyond 4–6 weeks, or accompanied by neurological symptoms. Earlier imaging is appropriate when red flags are present (see the back pain article).

Conservative treatment

Most sciatica improves substantially within 6–12 weeks without surgery. The standard pathway:

• Activity modification — avoiding aggravating movements but not bed rest
• Pain relief — paracetamol, NSAIDs, and for severe nerve pain, neuropathic agents such as gabapentin or pregabalin
• Structured physiotherapy with a focus on lumbar mobility, core stability, and graded exercise
• An epidural or selective nerve root injection in severe cases — particularly useful for buying time to allow rehabilitation

Around 60–80% of patients improve enough on this regimen to avoid surgery.

When to consider surgery

Surgery is recommended when:

• Severe pain persists despite 6–12 weeks of high-quality conservative care
• Neurological deficits are progressing
• Cauda equina syndrome develops (urgent surgery)
• Function is significantly limited and the patient is unable to work or sleep

The most common operation for a herniated disc is a microdiscectomy — a small open or minimally invasive operation through a 2–3 cm incision to remove the disc fragment compressing the nerve. Excellent leg pain relief in well-selected patients, typically 90% improvement; return to office work in 2–3 weeks; return to manual work in 6 weeks. For spinal stenosis, laminectomy (removal of the bony arch to decompress the nerves) is the standard option.

The decisions that matter

The most important decisions in sciatica are made jointly between patient and surgeon. How disabling is the pain? How long are you willing to wait? Are you prepared for the small risk profile of an operation versus the prolonged uncertainty of conservative care? There is rarely one right answer — but there is usually a right answer for a specific patient.