Medial Branch Nerve Block

Dr. Sumaiya Khan Apr 29, 2019
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Medial branch nerve block is a procedure that is done as a therapeutic and diagnostic procedure. Have a look at the procedure details, outcomes, risks, and contraindications of this procedure.
Medial branch block is a controlled surgical procedure where the medial branch nerves are targeted. Medial branch nerves are very small nerve branches that control the sensation to a part of the spine known as facet joints (the joint where each vertebra connects with the next).
These nerves are not responsible for sensation in muscles of the back, arms, or legs. They are only responsible for carrying pain signals to the spinal cord, from where, these signals eventually reach the brain, where the pain is registered. Thus, trying to identify and inactivate these nerves does not cause any adverse effect on any muscle of the body.
This is one of the reasons why bilateral medial branch block is such a favored procedure in patients suffering from chronic refractory back pain. This medial branch block injection can act as both, a diagnostic and/or a therapeutic procedure as it may help identify and/or treat back pain. Here are the details of this procedure and its complications.

Procedure

  • First, the patient is placed on the X-ray table and is asked to relax. For this, purpose, he can be given intravenous medication.
  • With the help of X-ray, the doctor identifies the target area for needle placement.
  • After the entry point for the needle is identified, the doctor applies a numbing medication on the site which may sting for a few seconds.
  • With a procedure called fluoroscopy, a small needle is directed towards medial branch nerves using X-ray guidance. The injection contains several drops of contrast dye to help confirm the location of medial nerves.
  • Once its confirmed, the medial branch block is given, consisting of a small mixture of numbing medicine which directly acts on medial nerves.

Possible Outcomes

  • The first effect of the medial branch block is that there is absolutely no significant impact of the procedure on the person, that is, the pain does not go away or decrease in intensity even a bit. Thus, from the ineffectiveness of the medial branch block on the pain, we can infer that the pain is not coming from the facet joints.
  • Another possibility is that after the procedure, the pain goes away temporarily; however, after a while, it comes back, and there is no further mitigation of pain. This means that the pain is, in all probability, coming from the joints.
  • The last and rarest outcome of the procedure may be that the pain goes away immediately after the procedure, and it progressively gets more and more diminished over a course of a few days. This would be indicative of a lasting effect of the medication on the pain.

Risks and Contraindications

  • People who are on blood-thinning medications, like low-dose aspirin, warfarin, etc should not undergo this procedure, especially, a cervical medial branch block. These patients run an added risk of developing complications, which is the reason why they are advised to stop their medication for a given period of time prior to the procedure. 
  • Patients who are immunocompromised or are suffering from other major debilitating illness must get a proper consultation before opting for the procedure.
  • Risks include an increase in pain. The pain may be aggravated after the procedure with worsened symptoms, and may be accompanied by a spinal block, epidural block, etc., requiring immediate pain relief.
  • There may also be bleeding or infection at the site of the injection. However, these complications are relatively rare and mostly avoidable, and hence, medial branch block is said to be a relatively safe procedure.
If a diagnostic medial branch block is done, depending on the reaction of nerves, further treatment plan as part of back pain relief is done. If the pain subsides after the procedure and returns after sometime, it's due to medial nerves. In this case, one can opt a procedure called radiofrequency lesioning, which selectively inactivates the medial nerves.
Thus, medial branch block is an excellent alternative to surgery, as so many of the risks involved with surgery are bypassed with the help of this procedure. Hence, if the block is successful, surgery can often be avoided. Therefore, medial branch block is soon turning out to be a favorable option for people suffering from long-standing back pain.
Disclaimer: This is for informative purposes only, and should not be used as a replacement for expert medical advice.