Medial Branch Injection Procedure

Medial branch nerve block injections are simple outpatient procedures that involve the insertion of a thin needle near the medial branch nerves of a facet joint to deliver anesthetic and/or corticosteroid medication.

Preparing for a Medial Branch Block Procedure

Before administering a medial branch block injection, a standard assessment process is typically conducted to ensure the procedure's suitability and safety^,:

• Reviewing the patient's health, including medical conditions, medications, and allergies
• Conducting a physical examination to locate the spinal region involved and to rule out alternative causes of pain
• Utilizing medical imaging and laboratory tests to evaluate facet joint damage or inflammation

Pain management doctors, anesthesiologists, or spine specialists (eg, physiatrists or orthopedic surgeons) are usually consulted to perform the initial assessment and medial branch block injection.

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Next steps after medical clearance for a medial branch block procedure

Individuals taking blood-thinning medications are usually advised to adjust their dose or temporarily stop the medication 2 to 7 days before the procedure to reduce the risk of excessive bleeding. To ensure safety, it is recommended to consult with the prescribing physician before discontinuing the medication or making any changes to the dosage.

Although it is not required, it is advisable to stop smoking before a medial branch block procedure as a proactive measure for improving health as smoking is associated with slowed healing and an increased risk of complications.

Medial Branch Block Injection Procedure: A Step-By-Step Guide

Medial branch blocks are typically performed in an outpatient setting while the patient is alert and awake, and the entire procedure typically takes between 15 and 30 minutes.

Sedation is avoided because it interferes with the interpretation of the results of the procedure, but a calming medication is offered for those who have significant anxiety related to the procedure.^,

If anti-anxiety medication is used, patients are not permitted to drive home and should schedule a friend or family member to drive them home. 

The medial branch block injection process is detailed below.

1. Positioning and preparation. The patient lies face-down on the procedure table, and a local anesthetic is injected to numb the skin and superficial tissues near the facet joint.^,
2. Needle placement. The doctor uses x-ray (fluoroscopy) or ultrasound imaging to guide the precise placement of two thin needles – one near each of the medial branch nerves supplying the targeted facet joint. In some cases, a single-needle technique may be used.^,
3. Confirmation of correct location. A small amount of contrast dye is injected through the needle(s) to confirm precise delivery of the medication near the medial branch nerve and avoid injecting the medication into a blood vessel.^,
4. Injection of medication. The doctor then slowly injects a local anesthetic onto each medial branch nerve.^,

Patients are observed for 30 to 60 minutes after the injection. During this time, they are asked to perform small movements that would usually provoke facet joint pain to assess pain relief.

Medial branch block injections for multiple spinal levels

When facet-mediated pain affects multiple spinal levels, it is reasonable to inject 2 to 3 levels in one session as this is more convenient for the patient and more efficient for diagnosing the source of pain.

Pain Relief After a Medial Branch Block

If the facet joint is the source of discomfort, partial or complete pain relief is typically experienced within 2 to 6 hours after a medial branch block. Maintaining a pain journal or documenting any alterations in pain symptoms on the day of the injection is recommended as it allows doctors to assess the procedure's effectiveness accurately.

Generally, a patient should experience at least 80% improvement in their pain during the first 2 to 6 hours after each diagnostic injection to be considered a candidate for radiofrequency neurotomy.^, 

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Duration of pain relief from a medial branch block

The local anesthetics used in medial branch blocks are short-acting, and the pain-relieving effects of the anesthetic are felt quickly but only last for 4 -12 hours, based on the type of anesthetic used.^,

Returning to normal activities after a medial branch block

Individuals are usually able to resume their normal activities on the day after a medial branch block procedure. 

Patients who undergo a diagnostic medial branch block should anticipate the return of their initial pain within a few days after the procedure. 

To prevent injury or worsening of discomfort, it's advisable to refrain from engaging in activities that require significant physical effort or strain, even during this pain-free interval, to avoid potential injury or worsening of discomfort. 

It is generally recommended to avoid activities that involve soaking in water (eg, bathtub, swimming, or hot tub) for at least 48 hours to reduce the risk of infection.