What is a Medial (Nerve) Branch (a.k.a., medial branch of the dorsal ramus) Nerve?
The spinal facet joints (a.k.a., zygapophyseal joints) are innervated or “supplied” by nerves called the “medial branches” (a.k.a., medial branch of the dorsal ramus). These nerves carry the pain signals from the facet joint to the spinal cord, which are in turn relayed to the brain, where the pain is interpreted.
At Aptiva Health, we offer same-day and walk-in appointments for spine injuries and conditions to evaluate, diagnose, and make the appropriate referral for additional treatment based upon your specific spine injury or condition. We treat spine injuries and conditions in our Spine, Pain Management, General Medicine, Orthopedics, and Physical Therapy departments.
What is the purpose of a Medial Branch Block?
If the nerves are “blocked” or “numbed,” they are unable to carry pain sensations from the facets to the spinal cord. It is like temporarily blocking the “wiring” between the facets and the brain. If your pain is due to facet joint arthritis, you will most likely have pain relief, with associated decreased stiffness. Unfortunately, this procedure is not getting rid of the arthritis, it is more like “faking out” the brain, making it think that the arthritis is not there, because the pain is not there.
How long does the injection take?
The actual injection takes only a few minutes. The amount of time is directly related to how many nerves are blocked.
What is actually injected?
The first injection consists of a short-acting local anesthetic (Lidocaine) and steroid (if appropriate). The second injection is completed with a mixture of a long-acting local anesthetic (Marcaine®) and a steroid medication (Dexamethasone® in the cervical or thoracic spine, and methylprednisone, a.k.a. Depo-Medrol® in the lumbar spine).
Will the injection hurt?
The procedure involves inserting a needle through the skin and deeper tissues, so there is some discomfort. However, the skin and deeper tissue will be numbed with a local anesthetic, using a very small needle, prior to inserting the spinal needle, which blocks the facet joint nerve.
How is the injection performed?
The injection is done with the patient lying on their stomach. The skin of the neck or back is cleaned with Betadine (or Hibiclens) prior to initiation of the injection. The injection is done under fluoroscopic (i.e., “live”) x-ray, in order to assure appropriate location for each injection.
How many injections do I need to have?
In order to reduce the risk of a “False Positive” (i.e., the injection appears to work, but the effect is actually due to a placebo effect), or a “False Negative” (i.e., the injection appears not to work, but actually does), this procedure is performed at 2 separate occasions, usually 1-2 weeks apart. If both injections are effective, this significantly reduces the risk of a “False Positive”, or “False Negative” result. If your pain is on both sides of your back or neck, these injections will need to be completed on one (generally the most symptomatic) side, followed by the other. Again, this reduces the risk of incorrect interpretation of the block results.
How long does the effect of the medication last?
The injections are diagnostic blocks and will typically last as long as the local anesthetic (i.e., 24-48 hours). Since the both injections are performed with steroid, this effect may be felt for approximately 3 to 5 days and may even last for several weeks.
What should I expect after the injection?
Immediately after the injection, you may notice your pain is significantly decreased, or even alleviated completely. This immediate effect is due to the local anesthetic used during the injection. This effect may last for only a few hours, and once your pain returns, you will most likely experience a “sore” neck or back for 24 to 48 hours. This is due to needle insertion through the back muscles, along with irritation from the steroid medication. It is important to keep close track of your pain and stiffness immediately following the injection, as well as the next several days. You will be asked about percentage relief immediately following both blocks, as well as their lasting effects. These percentages will be recorded on your follow-up office visit after both blocks (e.g., “I received 50% relief from block #1, which lasted for 2 days, and 80% relief from block #2, which lasted for 2 weeks”). Your response to the injections will determine if the facets are the cause of your pain, and whether you are an appropriate candidate for radiofrequency ablation (RFA).
Will the Medial Branch Block help me?
If the pain is originating mostly from the facet joints, you should benefit from this procedure on a temporary basis. Some do get a “placebo response” and others may get a “False-Positive” response. Please remember that these are diagnostic injections and may only last for a few hours. The medial branch blocks are done to determine whether the pain is coming from the facet joints. If the pain is coming from the facet joints, we will recommend “Radiofrequency Nerve Ablation,” which will “burn” or “numb” (i.e., cauterize) the same nerves for many weeks to months (or even years).
If the injections work, what’s next?
If both MBB blocks are effective (i.e., adequate percentage relief of pain), the next step is to perform a medial branch radiofrequency nerve ablation (RFA). During this procedure, the skin and deep tissues are anesthetized with local anesthetic, then a probe is placed on the medial branch nerve. The nerve is then burned (i.e., cauterized), completely blocking pain impulse transmission from the facet joint to the brain. This procedure, if effective, can result in alleviation of pain for 6 months to 2 years. The nerve will eventually regenerate (i.e., grow back), and the amount of time the RFA will be effective is directly related to how long it takes the body to regenerate the nerve.
Will I be “put out” for this procedure?
The 2 medial branch blocks are performed under local anesthesia, and there is no sedation. This is necessary to assure appropriate interpretation of the block results. During the RFA procedure, more local anesthetic is used, which will make you more comfortable. You will not be sedated “put to sleep”, since it is necessary to ask you questions during the procedure, to ensure your safety.
What should I do after the procedure?
You should have a ride home following the RFA, though this is not necessary following the facet blocks. We advise patients to take it easy for a day or so after the RF procedure, applying ice to the affected area, often done most effectively using “ice massage”. Patients will generally be given muscle relaxants for the first week following the RF procedure, in order to reduce muscle spasms, which are common. You may perform your usual activities as tolerated.
Can I go to work the next day?
Unless there are complications, you should be able to return to work the next day. The most common thing you may feel is a sore back (if performed on the thoracic or lumbar spine), or a sore neck (if performed on the cervical spine).
What are the risks and side effects?
Generally speaking, this procedure is safe. However, as with any procedure, there are risks, side effects, and the possibility of complications. The most common side effect is pain, which is temporary. Some of the risks involve infection, bleeding, worsening of symptoms, spinal block, epidural block, and nerve or spinal cord damage. Fortunately, the serious side effects and complications are uncommon.
Who should NOT have this injection?
You should not have the injection if you are allergic to any of the medications to be injected, if you are on a blood thinner (e.g. Coumadin®, Plavix®, Eliquis®, etc.), or if you have an active infection.