Sciatica vs "Back Pain" — How to Tell if a Nerve Is Involved
Quick Answer
True sciatica means nerve root compression causing pain that follows a specific path down your leg—usually past the knee. Mechanical back pain stays local or spreads diffusely. The distinction matters because nerve involvement changes both prognosis and treatment urgency.
If your leg pain is worse than your back pain, follows a dermatomal pattern, and comes with numbness or weakness, you likely have nerve compression. If pain stays in your back or buttock and moves around unpredictably, it's probably mechanical.
MRI timing matters: early imaging helps if you have progressive weakness or severe radicular pain not improving with conservative care. For pure mechanical pain, we often wait 6 weeks before ordering advanced imaging.
A Common Scenario
A patient comes in saying they have "sciatica." When I ask where it hurts, they point to their lower back and maybe their buttock. No leg pain past the knee. No numbness. No weakness.
That's not sciatica. It's mechanical low back pain, possibly with some referred pain into the hip or upper thigh. The treatment approach is completely different.
Then someone else walks in limping, tells me their back barely hurts, but their right leg is "on fire" from buttock to foot. They can't stand on their toes on that side. They have numbness on the bottom of their foot. That's nerve compression—and it changes everything about how we approach their care.
Symptom Patterns That Matter
The word "sciatica" gets misused constantly. Technically, it means irritation or compression of the sciatic nerve or its nerve roots (usually L5 or S1). The sciatic nerve runs from your lower back, through your buttock, down the back of your thigh, and into your lower leg and foot.
True radicular pain—nerve root pain—has specific characteristics. It's sharp, electric, burning, or shooting. It follows a predictable path. It often gets worse with certain movements: bending forward, sitting, coughing, or sneezing.
Mechanical back pain is different. It's achy, stiff, or sore. It stays in your back or spreads vaguely into your hips or thighs. It doesn't follow a nerve distribution. It usually improves with movement after initial stiffness.
| Feature | True Sciatica (Nerve) | Mechanical Back Pain |
|---|---|---|
| Pain location | Leg pain worse than back pain, usually past knee | Back, buttock, maybe upper thigh |
| Pain quality | Sharp, electric, burning, shooting | Achy, stiff, sore, dull |
| Distribution | Follows specific nerve path (dermatomal) | Diffuse, moves around, non-specific |
| Numbness/tingling | Common, in specific areas (e.g., top of foot, outside of calf) | Rare, vague if present |
| Weakness | Possible (foot drop, toe weakness, ankle weakness) | No true weakness, just guarding from pain |
| Worse with | Sitting, forward bending, coughing, sneezing | Prolonged positions, twisting, lifting |
| Straight leg raise | Positive (reproduces leg pain) | Negative or just back tightness |
Nerve root compression follows predictable patterns. L5 affects the top of the foot and big toe. S1 affects the outside of the foot and small toes.
What I Look For on Exam and Imaging
On physical exam, I'm checking several things:
Straight leg raise: I lift your leg while you're lying down. If this reproduces your leg pain (not just back tightness) before we get to 60 degrees, that's a positive test for nerve tension.
Motor strength: Can you walk on your heels? On your toes? Can you lift your big toe against resistance? Specific weakness patterns tell me which nerve root is compressed.
Reflexes: Diminished or absent ankle reflex suggests S1 involvement. Knee reflex changes point to higher levels.
Sensation: I check specific areas. Numbness on top of the foot? L5. Outside of the foot? S1. These aren't random—they follow dermatomal maps.
If your exam suggests nerve compression, or if your symptoms aren't improving after 4–6 weeks of appropriate conservative care, I order an MRI. Not a CT. Not an X-ray. MRI shows soft tissue—discs, nerves, ligaments.
What I'm looking for: Is there a herniated disc? Where is it? Is it compressing a nerve root? Is there canal stenosis? Foraminal stenosis? Does the imaging match your symptoms?
That last part is critical. Lots of people have disc bulges on MRI with zero symptoms. The imaging has to correlate with your clinical picture. If you have left leg pain and your MRI shows a right-sided disc herniation, that's not your problem.
What You Can Try First
Most acute radicular pain improves without surgery. The natural history of a herniated disc is actually favorable—your body resorbs disc material over time, inflammation settles, and nerve irritation resolves.
Here's what I recommend initially:
Activity modification: Avoid prolonged sitting, forward bending, and heavy lifting. Stay active within your tolerance—walking is usually fine. Bed rest beyond 1–2 days makes things worse.
Anti-inflammatories: NSAIDs like ibuprofen or naproxen can help if you tolerate them. They reduce nerve root inflammation, not just pain.
Physical therapy: Once acute pain settles (usually 2–3 weeks), PT focuses on core stability, nerve gliding exercises, and posture. Not aggressive manipulation early on.
Epidural steroid injection: If you're not improving after 4–6 weeks, a targeted injection can reduce inflammation around the nerve root. It's not a cure, but it can break the pain cycle and let you participate in PT.
For mechanical back pain without nerve involvement, the approach is similar but less urgent. We focus on movement, core strengthening, and addressing any underlying instability or muscle imbalance.
When Surgery Becomes Reasonable
Surgery for sciatica is elective in most cases. The main indication is persistent, disabling leg pain despite appropriate conservative treatment—usually 6–12 weeks.
I consider surgery sooner if:
- You have progressive motor weakness (foot drop developing or worsening)
- Your pain is so severe you can't function despite medications
- You've had multiple recurrent episodes and want definitive treatment
- Conservative care has clearly failed and your quality of life is significantly impaired
The goal of surgery is decompression—removing whatever is compressing the nerve. For a herniated disc, that's usually a microdiscectomy or endoscopic discectomy. We remove the herniated fragment, decompress the nerve, and leave the rest of the disc intact.
Success rates are high for well-selected patients: 85–90% get significant leg pain relief. Back pain is less predictable. Recovery is typically 2–6 weeks for return to normal activity, depending on your job and the surgical approach.
Risks include infection (low, <1%), nerve injury (rare, <1%), recurrent herniation (5–10% over time), and dural tear (5%, usually not a major issue). We discuss all of this in detail before proceeding.
For pure mechanical back pain without nerve compression, surgery is rarely indicated. Fusion might be considered for instability or severe degenerative changes, but that's a different conversation with different risk-benefit calculations.
Red Flags — Seek Urgent Care
Go to the emergency department or call your surgeon immediately if you develop:
- Bowel or bladder dysfunction: Loss of control, inability to urinate, or numbness around your genitals/anus (saddle anesthesia). This suggests cauda equina syndrome—a surgical emergency.
- Progressive weakness: Foot drop that's getting worse, inability to stand on toes or heels, leg giving out.
- Fever with back pain: Especially if you have a history of IV drug use, recent infection, or immunosuppression. Could indicate spinal infection.
- History of cancer: New back pain with a cancer history needs urgent imaging to rule out metastatic disease.
- Significant trauma: Fall, car accident, or injury with new neurological symptoms.
Decision Framework
Identify the pain pattern
Leg pain worse than back pain, past the knee, in a specific distribution → likely nerve compression. Back pain only or vague hip/thigh pain → likely mechanical.
Check for red flags
Bowel/bladder changes, progressive weakness, fever, cancer history, trauma → urgent evaluation needed.
Start conservative treatment
Activity modification, NSAIDs, PT. Give it 4–6 weeks unless symptoms are severe or worsening.
Consider imaging if not improving
MRI if radicular symptoms persist beyond 4–6 weeks or if there's weakness. Match imaging findings to clinical symptoms.
Epidural injection if appropriate
Can help break the pain cycle and facilitate PT. Not a long-term solution, but useful in the right context.
Surgical consultation if conservative care fails
After 6–12 weeks of appropriate treatment without improvement, or sooner if there's progressive weakness or intolerable pain.
Medical Disclaimer: This article provides general educational information about sciatica and back pain. It is not personal medical advice and should not replace consultation with a qualified healthcare provider. If you're experiencing back or leg pain, seek evaluation from a spine specialist who can assess your specific situation.
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