Medial Branch Nerve Block
Overview
Medial branch nerve block is to inject anesthetic agent to the junction area between superior process and transverse process of the facet joint. It blocks nerve temporarily. It is a diagnostic test, not a treatment. It is trying to confirm if the pain comes from the facet joint. The medial branch nerve branches off from its nerve root and passes through the junction area between superior process and transverse process of the facet joint, and then innervates to facet joints. The medial branch nerve carries pain signal from facet joint to brain. When the nerve is blocked with anesthetic agent, the pain signal from facet joint is blocked. The pain does not travel to brain any more. Then the pain can be reduced or relieved temporarily and it confirms that the pain comes from the face joint. Medial branch nerve radiofrequency is indicated once it is confirmed that the pain comes from facet joint. Medial branch nerve radiofrequency blocks medial branch nerve permanantly. It is the treatment for facet joint pain. Please click here for further information about medial branch nerve radiofrequency. The procedure can be done in doctor’s office or in a hospital.
The neck, mid-back and low back pain commonly comes from facet joints. Facet joints are tiny small joints between every two vertebrae. There are two facet joints in each level. Facet joints are lining up from neck to the low back and it is located in the back of spine. This pain is referred to as facet joint pain syndrome, facet arthropathy, osteoarthritis, facet arthritis.
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Facet joint
superior articular process
medial branch nerve
transverse process
transverse process
superior articular process
The medial branch nerve branches off from its nerve root and passes through the junction area between superior process and transverse process of the facet joint, and then innervates to facet joints.
The medial branch nerve is located at the junction area between superior process and transverse process of the facet joint.
Indications for Medial Branch Nerve Block
The following pain conditions are indicated for medial branch nerve block:
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Low back pain
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Neck pain
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Mid-back pain
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Postlaminectomy syndrome
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Failed back surgery syndrome
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History of spine fusion
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Post-whiplash injury
The medial branch nerve block is a diagnostic procedure. The purpose of this block is to confirm if the pain indeed comes from facet joint. The pain in the neck and back can be very complicated and sometimes we just do not know where the pain comes from even though we have all modern diagnostic tools. The medial branch nerve block can help us to sort it out. This block can be considered as confirmatory injection and it is the gold standard for diagnosing the facet syndrome currently.
Local anesthetics such as Marcaine (long-acting Norvocain) is injected to the junction area between superior process and transverse process of the facet joint to block medial branch nerves, and we can then observe the patient to see if she or he has good pain relief for a period of time, or if she or he can aggravate his or her pain with painful activities. The result will guide the treating physician for the treatment subsequently.
There are three possibilities:
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The pain is resolved completely. The pain comes from facet joint we blocked solely. Treatment should focus on the facet joint.
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The pain is reduced partially. The pain comes from the facet joint partially. If the patient has significant pain relief, we can continue to treat facet joint pain. However, there is other pain generator or source we may have to look for.
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The pain is unchanged at all. This means that the pain does not come from the facet joint we blocked. The treating physician has to look for other source of the pain.
Contraindications
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Systemic infection
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Skin infection over puncture site
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Bleeding disorders or coagulopathy
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Allergy to the medications
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Pregnancy
Preparation for Procedure
The treating physician will review the medications the patient takes again. The patient should provide the treating physician full medication record, including prescription medications and over-the-county medications. The blood thinner may have to be stopped because it can thin the blood and increase risk of bleeding. Follows are the most common medications which may increase the risk of bleeding:
Anticoagulants:
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Coumadin has to be stopped 5 days before the injection and check PT/INR in the morning of the injection. INR has to be around 1 to proceed with the procedure.
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Lovenox has to be stopped 24 hours before the nerve block.
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Plavix, Pradaxa, Eliquis and Xarelto should also be stopped before the procedures.
Anti-inflammatory medications(NSAID):
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Ibuprofen, Motrin, Advil, Aleve, Naproxen, aspirin and other anti-inflammatory medications should be stopped for 7 days before the nerve block.
The patient should not eat or drink anything after midnight the night before your procedure if you are going to have IV sedation. The patient may also need to consult with his or her physician to find out what other medications he or she can take or can’t take.
The physician may prescribe Valium for the patient if the patient is very anxious and if the patient doesn't need sedation.
The patient needs a driver to drive him or her home after the procedure. The patient may need driver to drive him or her to the facility and home if the patient takes Valium.
Procedure
The procedure can be performed in a doctor's office or in the hospital. The nerve block itself may only take about 5 minutes. However, the entire procedure may take about 20 minutes.
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The treating physician may review the patient's case again with the patient and answer questions before the procedure. The patient should always mention their allergy to the treating physician before the procedure.
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The patient is going to sign consent form first.
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The patient is brought to the procedure room and placed in the prone position (face down) in a surgical table.
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An X-Ray machine (fluoroscope) is brought into field to locate injection sites.
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The treatment area is disinfected with Beta-dine three times.
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Local anesthetic agent is used to numb the injection sites with a very fine needle. The patient may feel some discomfort with transient burning sensation.
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Spinal needles are then inserted under the guidance of real-time fluoroscope.
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The needle is advanced to the junction area of superior process and transverse process of the related facet joint.
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X-Ray is used to confirm the needle position.
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A long-term local anesthetic agent is injected into the area.
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The needle is withdrawn and puncture area is dressed with Band-Aid or any other sterile dressing.
The patient will be observed for about 20 minutes after the procedure.
The X-Ray figure shows that two needles are located at the junction area between superior process and transverse process of the facet joint.
A needle is located at the junction area between superior process and transverse process of the facet joint.
Post Procedure Care
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The patient should not drive the day of the injection unless approved by the treating physician.
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If sedation was used, the patient should not drive for 24 hours after the procedure.
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The patient should follow up with treating physician in about 1 week or so to assess the effect of the nerve block and to plan further treatment
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The patient should have pain dairy, i.e. write down the pain level before the nerve block and every hour for 6 hours after the block. This will help the treating physician to find out if the block has any effect on the patient and planning future tests and treatment. This is critical for the patient because it will tell the treating physician if the pain is generated in the blocked joint. There are several possibilities:
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There is significant pain relief for the first 4-6 hours: It confirms that facet joint is the pain generator. The patient may proceed with the second medial branch nerve block or medial branch nerve radiofrequency.
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There is no significant pain relief for the first 4-6 hours: The pain does not come from the facet joint. Other source of pain should be searched.
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The patient may hold pain medicine within the first six hours after the injection.
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The patient may remove dressing in 6 hours and may take shower at the night.
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The pain may have significant pain relief for 6 or more hours after the block. It is due to effect of local anesthetic. The pain is to come back after anesthetic wear off. The pain can be worse occasionally. It can be because the patient does not have the pain for a while and does not tolerance for the same pain well any more.
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If the injection site is uncomfortable after the injection, the patient may apply cold pack to reduce the pain for the first 48 hours.
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The patient may resume regular activities after the injection. However, the patients should avoid doing any strenuous activities. The patients should get advice from the treating physician when to start regular exercise and what precaution should be followed.
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If the patient has sign of infection, such as fever, chills, or redness or drainage at the treatment site or have temperature of 101 degrees or greater, call the treating physician’s office or go to emergency room if the treating physician is not available.
Risks and Complications
The potential risks and complications are very low and complications are rare.
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Bleeding
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Infection
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Nerve or spinal cord damage
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Allergy to local anesthetic agent
Those are very rare risks and complications. However, as general rule, patients should always consult with his or her treating physician about the risks and complications about the procedure and mention their allergy to treating physician before any procedures.
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