Overview
The sympathetic chain runs along the spine and helps regulate blood flow, temperature, sweating, and certain pain pathways. In some people, sympathetic overactivity can contribute to persistent pain and autonomic symptoms, such as burning discomfort, extreme sensitivity to touch, swelling, or changes in skin colour and temperature.
The T2 and T3 levels of the sympathetic chain sit in the upper thoracic region and can influence sympathetic output to parts of the upper limb and chest. A block at these levels aims to reduce sympathetic nerve activity and may help interrupt the pain amplification cycle. It can also provide useful diagnostic information, helping confirm whether the sympathetic system is an important contributor to symptoms.
This treatment is typically considered when symptoms suggest sympathetic involvement and when conservative care has not provided adequate relief.
Who this treatment helps
A T2 or T3 sympathetic block may be considered for people with:
• Sympathetic pain affecting the arm or hand
• Complex regional pain syndrome in the upper limb in selected cases
• Burning pain or marked sensitivity with temperature or colour changes
• Circulation related symptoms such as coldness or mottling of the hand
• Pain that limits movement, sleep, or rehabilitation progress
• Symptoms that have not responded adequately to medication or physiotherapy
A consultation is required to confirm suitability and to ensure the symptom pattern matches a condition likely to respond to sympathetic blockade.
What is a T2 or T3 Sympathetic Block
This procedure involves placing a fine needle near the sympathetic chain at the T2 or T3 level under imaging guidance. A local anaesthetic is injected to temporarily reduce sympathetic nerve activity. In some cases, additional medication may be used depending on the clinical goal.
The block aims to:
• Reduce sympathetic nerve driven pain sensitivity
• Improve circulation related symptoms in selected cases
• Help confirm sympathetic involvement when the diagnosis is unclear
• Support rehabilitation by improving comfort with movement
Fluoroscopy or CT guidance is often used to support accuracy and safety, given the depth of the target and nearby structures.
What to expect during the procedure
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Consultant review and confirmation of the plan and side being treated
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Comfortable positioning on the procedure table, depending on the technique used
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Cleaning of the skin and local anaesthetic to numb the area
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Imaging guidance to position the needle safely near the sympathetic chain
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Injection of the local anaesthetic, sometimes with contrast confirmation
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Monitoring for a short period after the procedure before discharge
Most procedures are performed as a day case.
After the procedure
Following the block, you may notice:
• Warmth or colour change in the arm or hand on the treated side
• Temporary reduction in pain or sensitivity if the sympathetic chain is involved
• Mild soreness at the injection site
• Temporary lightheadedness
The local anaesthetic effect is usually short lived, but the response helps guide next steps. Some patients may benefit from a series of blocks or from longer lasting options depending on the diagnosis and response.
Your consultant may recommend keeping a brief symptom record to capture changes in pain, temperature, function, and daily activity.
Benefits
• May reduce sympathetic pain and nerve sensitivity in the upper limb
• May improve circulation related symptoms such as coldness or skin colour change
• Can help confirm sympathetic involvement as a diagnostic step
• Minimally invasive and typically performed as a day case
• May support physiotherapy and rehabilitation by improving comfort
• May reduce reliance on medication in selected cases
Possible risks and side effects
T2 and T3 sympathetic blocks are generally safe when performed by experienced clinicians using imaging guidance. Possible risks and side effects may include:
• Temporary soreness or bruising
• Temporary increase in pain
• Lightheadedness
• Allergic reaction to medication or contrast dye, uncommon
• Infection or bleeding, rare
• Very rarely irritation of nearby nerves or structures
Your consultant will discuss individual risks and how they are minimised.
When to consider other options
If symptoms do not improve, or if another pain pathway is more likely, your consultant may discuss:
• Stellate ganglion block
• Lumbar sympathetic block for lower limb symptoms
• Medication optimisation for nerve pain and sensitisation
• A structured rehabilitation approach
• Multidisciplinary pain management for complex cases
Safety note
Please inform your consultant if you take blood thinners, have diabetes, allergies, active infection, are pregnant, or have had previous reactions to local anaesthetic or contrast dye. You may need someone to accompany you home depending on the medications used.
Arrange a consultation to discuss whether a T2 or T3 sympathetic block is suitable for your symptoms.