Overview
A lumbar nerve root block is used to diagnose and treat nerve related leg pain. Each spinal nerve root supplies sensation and movement to a defined area of the leg. When a particular nerve root becomes irritated because of disc bulge, spinal narrowing, inflammation, or degenerative change, it may produce pain, numbness, tingling, or weakness following a specific pattern down the leg.
A lumbar nerve root block targets one nerve root at a time. By placing medication directly next to the affected nerve, the procedure can help reduce inflammation and confirm whether that nerve root is responsible for the symptoms. This information can guide further treatment decisions.
Who this treatment helps
Lumbar nerve root block may be considered for people with:
- Leg pain following a clear nerve distribution
- Suspected irritation of a single nerve root
- Disc related leg pain or sciatica
- Persistent symptoms not improving with conservative care
- Diagnostic clarification before further procedures or surgery
A specialist consultation is required to confirm suitability and identify the nerve most likely to be responsible for the symptoms.
What is a lumbar nerve root block
A lumbar nerve root block involves placing a fine needle next to the targeted nerve root using imaging guidance. A small amount of local anaesthetic, sometimes combined with steroid medication, is injected around the nerve.
The local anaesthetic can temporarily numb the nerve and help confirm that it is the source of symptoms. When steroid medication is used, it may also reduce inflammation and provide longer lasting pain relief.
What to expect during the procedure
Your consultant will review the treatment plan and explain the procedure before treatment begins.
- Consultant assessment and confirmation of the treatment target
- Comfortable positioning on the procedure table
- Local anaesthetic used to numb the skin
- Image guided needle placement next to the nerve root
- Targeted medication delivery
- Short observation period before discharge
The procedure is usually performed as a day case treatment and typically takes only a short time to complete.
After the procedure
Following a lumbar nerve root block it is normal to experience some temporary changes in the treated leg.
- Temporary numbness or mild weakness in the leg
- Mild soreness at the injection site
- Gradual improvement in symptoms over time
Most people return to normal activities the next day, although strenuous activity should be avoided for a short period.
Benefits
- Helps identify the exact source of nerve related pain
- May reduce inflammation around the affected nerve
- Minimally invasive procedure
- Supports accurate treatment planning
- May reduce the need for unnecessary procedures
Possible risks and side effects
Lumbar nerve root block is generally safe when performed by experienced clinicians, but all procedures carry some risk.
- Temporary increase in pain
- Local bruising or soreness
- Infection, which is rare
- Bleeding
- Allergic reaction to medication
- Very rare nerve irritation
Your consultant will discuss the potential risks and expected benefits during your assessment.
When to consider other options
If symptoms persist or the response to injection is limited, other treatments may be discussed. These may include epidural steroid injection, epidural lysis of adhesions and PRP, rehabilitation programmes, medication review, or further specialist evaluation depending on the diagnosis.
Safety note
Please inform your consultant about medications, allergies, diabetes, bleeding disorders, active infection, or pregnancy before treatment. This helps ensure that the procedure can be planned safely.
Arrange a consultation to discuss whether a lumbar nerve root block may be suitable for your symptoms.
You can also explore our leg pain and sciatica treatments, view all pain treatments, or learn more about our pain management services.