A medial branch block is a diagnostic test that places a small dose of local anesthetic on the nerves carrying pain from a facet joint. If your usual pain eases while it works, radiofrequency ablation is more likely to help. At YOUNIFY Clinic, a Healthy Aging & Wellness Center based in Bangkok, Thailand, in Silom, we test first.
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Contents
Key Takeaways
- A medial branch block (MBB) is a short diagnostic test under X-ray guidance, not a treatment.
- Clear relief while the local anesthetic lasts suggests the facet joint is the source, so radiofrequency ablation (RFA) is more likely to help.
- Guidelines commonly use one or two diagnostic blocks before RFA. The evidence for these procedures is debated, and testing first helps avoid treating nerves that are not carrying your pain.
What is a medial branch block?
A medial branch block briefly numbs the tiny medial branch nerves that carry pain signals from the facet joints, the small paired joints at the back of the spine.
Irritated facet joints can cause a deep ache in the neck or lower back. Each joint has two medial branch nerves, which do not control strength or feeling in the limbs. Our pain medicine physician guides a thin needle by X-ray and places local anesthetic beside them. The effect lasts some hours, and then your usual pain returns.
Why is a diagnostic block done before radiofrequency ablation?
The block comes first because it shows whether the facet joint is the likely source before any nerve is treated with heat.
Pain can also come from discs, nerve roots, the sacroiliac joints, or muscles, and facet wear often shows on scans of people without pain. If your usual pain drops meaningfully while the anesthetic works, radiofrequency ablation of the same nerves has a better chance of helping. Because one block can mislead, the American Society of Interventional Pain Physicians (ASIPP) facet joint guideline and others commonly use one or two diagnostic blocks before RFA. Skipping the test lowers the chance that RFA helps, because the heat may reach nerves that are not carrying your pain.
How do a medial branch block and RFA compare?
The block tests the joint, and RFA treats it.
| Medial branch block (MBB) | Radiofrequency ablation (RFA) | |
|---|---|---|
| Purpose | Tests whether a facet joint is the pain source | Aims to reduce pain signals from confirmed joints |
| What is used | Thin needle, X-ray guidance, local anesthetic | Thin probe, X-ray guidance, radiofrequency heat |
| How long the effect lasts | Some hours | Months in some people; nerves can regrow |
| Day of procedure | Outpatient, most patients go home the same day | Outpatient, as for the block |
| Starting price | starting from THB 22,000 | starting from Confirmed in your written quotation after assessment. |
Prices depend on levels and sides. See how long RFA lasts and RFA and epidural injection costs.
How strong is the evidence?
The evidence is debated, and you should know this before deciding.
A 2025 guideline in The BMJ made a strong recommendation against radiofrequency ablation for chronic non-cancer spine pain, while other guidelines such as ASIPP and NICE take a more selective view. Testing first does not settle that debate, but it helps avoid treating nerves that are not carrying your pain. Exercise stays at the center of your plan whatever the result.
What is the block day like?
It is a short outpatient visit under local anesthetic, and most patients go home the same day with a pain diary.
1. We review your medicines beforehand, especially blood thinners, with your prescribing doctor.
2. You score your usual pain from 0 to 10, so there is a clear starting point.
3. Thin needles are placed under X-ray guidance, with light or no sedation so the result is your own.
4. You score your pain again at set times, often hourly, after movements that usually hurt, and note when relief began and ended.
5. Someone accompanies you home, and we review the diary with you before any decision about RFA.
When to see a doctor urgently
Seek emergency care if neck or back pain comes with:
- New weakness in an arm or leg
- Loss of bladder or bowel control
- Numbness in the saddle area
- Fever
- Pain after a major fall
- Unexplained weight loss
- New difficulty with balance or fine hand movements
When we may advise against a procedure
We may advise against a block or RFA, or suggest waiting, when:
- Blood thinners cannot yet be managed safely
- There is an active infection
- You are pregnant, since X-ray guidance is used
- The pain source is not confirmed or points elsewhere
- Diabetes is poorly controlled and a corticosteroid injection is considered
- The expectation is a lasting fix from either procedure alone
Physician perspective
[รอ approve] In our clinic, we treat the diagnostic block as a question that needs a clear answer. The evidence for radiofrequency ablation in chronic spinal pain is still debated, so the block is the checkpoint that protects you from a procedure you do not need. Before booking, we check that the pain fits a facet joint: mainly in the neck or back, and worse when you lean back or twist. We then choose the levels that most closely match your symptoms and agree in advance how much the pain must drop to count as meaningful. If relief falls short or is unclear, we do not go straight to ablation at those levels; we discuss the next options, and exercise continues whatever the result.
An illustrative example
Illustrative example, not a real patient: an office worker has lower back pain, worse when standing and leaning back, despite physiotherapy. The MRI report shows facet joint wear. After a block at two levels, the diary shows clear relief in the afternoon and the usual pain returning by evening. The physician then discusses the evidence and the next step.
What happens next
1. Send your MRI or X-ray report and a short history.
2. Our pain medicine physician reviews it.
3. You receive a written plan and a written quotation.
4. If suitable, the block is done at our Silom clinic near BTS Sala Daeng.
5. We review your diary together and agree on the next step.
Send your imaging and a short history for a physician review by WhatsApp (+66 81 556 9696, https://wa.me/66815569696) or LINE (https://lin.ee/5MIGher). See our medial branch block page and chronic pain service.
Frequently Asked Questions
Does a medial branch block hurt?
Most patients feel a brief sting from the skin anesthetic and some pressure as the needles are positioned. The needles are thin and guided by X-ray, and most patients go home the same day. Mild soreness may follow for a short time.
Why did my pain come back after the block?
That is expected. The local anesthetic wears off after some hours, and your usual pain returns. What matters is whether the pain dropped clearly while it was working. A clear drop followed by a return of pain is the pattern of a positive test.
What if the block does not help?
That is still a useful result. It suggests the facet joints are unlikely to be the main source, so RFA of those nerves would be unlikely to help. Your physician then considers other sources, such as a disc, a nerve root, or the sacroiliac joint.
Can I have RFA on the same day as the block?
In our clinic, RFA is planned as a separate visit. The diary is read first, and sometimes a second block is advised. This gives you time to see your result, ask about the evidence, and receive a written quotation before committing to treatment.
How much does a medial branch block cost in Bangkok, and does insurance cover it?
A medial branch block at YOUNIFY Clinic is priced starting from THB 22,000, and RFA starting from Confirmed in your written quotation after assessment., confirmed in a written quotation. We prepare a medical report and an itemized receipt for your own insurance claim, and coverage depends on your policy.
Is a facet joint injection the same as a medial branch block or RFA?
No. A facet joint injection places medicine, sometimes a corticosteroid, inside the joint itself. A medial branch block tests the nerves outside the joint, and RFA treats those nerves with heat. A facet joint injection is quoted after a physician assessment.
References
- Manchikanti L, et al. Comprehensive Evidence-Based Guidelines for Facet Joint Interventions in the Management of Chronic Spinal Pain (ASIPP Guidelines). American Society of Interventional Pain Physicians (ASIPP), 2020.
- Busse JW, et al. Commonly used interventional procedures for non-cancer chronic spine pain: a clinical practice guideline. The BMJ, 2025.
- Low back pain and sciatica in over 16s: assessment and management (NG59). National Institute for Health and Care Excellence (NICE), 2016, updated 2020.
- Interventional Spine and Pain Procedures in Patients on Antiplatelet and Anticoagulant Medications (Second Edition). ASRA Pain Medicine, Regional Anesthesia and Pain Medicine, 2018. · DOI 10.1097/AAP.0000000000000700
Medical Note
This article is for general information and does not replace medical examination, diagnosis, or treatment. If symptoms are severe, changing quickly, or urgent, seek medical care promptly.
Individual results may vary. Please consult a doctor before treatment.
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