FAQ’s on Medial Branch Block
What is a medial branch nerve block?
A medial branch block is an injection performed for arthritis in the spinal joints. The joints, called facet joints, are about the size of a thumbnail and are on each side of the spine at every level from the skull down to the sacrum.
Tens of millions of Americans experience pain from arthritis. When a person has arthritis in one of the spinal joints, usually it is present in a few.
Each joint has a nerve supply which allows it to feel pain from arthritis. This nerve supply comes from small nerve endings that come off of spinal nerve roots called medial branches.
A “block” of the medial branch involves placement of numbing medicine and steroid around the spinal joint that has pain from arthritis.
Why is a medial branch block performed?
There are two reasons to perform a medial branch block. The first is for a diagnostic purpose. When a pain management doctor works up neck or back pain and deems the pain to be coming from that spinal joint, a medial branch block can confirm the suspicion.
The second reason to perform a medial branch block is for therapeutic reasons. The injection can provide pain relief for a few months at a time.
What Conditions benefit from the Injection?
Medial branch blocks are very helpful for either neck pain, mid-back pain or low back pain coming from an arthritis problem in the facet joints. These are the spinal joints in the back of the spine responsible for allowing the considerable range of motion humans enjoy with their spine. Unfortunately as arthritis develops, that movement can become painful, and a medial branch block can reduce that discomfort. The injection will not help leg or arm pain, but it may help also reduce some of the referred pain that comes from a painful facet joint such as in the sides of the back/neck, buttock and even shoulder pain.
At times, headaches may be coming from arthritis in the neck. It may be possible to reduce both the frequency and severity of headaches with a medial branch block around facet joints of the neck.
How is the injection performed?
A pain management doctor typically uses real time x-ray for the procedure, called fluoroscopy. IV sedation is not usually necessary for the procedure. The skin and soft tissues are numbed down to the area of the spinal joint. Then contrast is injected around the joint to ensure accuracy.
Once positioning is verified, the doctor injects the numbing medicine and steroid over both areas of medial branches. Each joint actually has 2 medial branch nerve endings supplying the joint with sensation, so the injection is placed in 2 distinct places to cover both medial branches.
Once the injection is completed, the patient is monitored for a time to ensure stable vital signs and no allergic reaction occurs.
What are the outcomes?
Medial branch block injections work very well for both of their purposes, both diagnostic and therapeutic. The average duration of pain relief from medial branch blocks has been shown to be over 4 months (Manchikanti et al, Int J Med Sci. 2010 May 28;7(3):124-35).
With regards to how well medial branch blocks work in diagnosing the facet joint as a pain generator, the evidence has been strong (Datta et al, Pain Physician. 2009 Mar-Apr;12(2):437-60.
If the pain relief works and then wears off from the block, a radiofrequency ablation of the joint(s) may provide pain relief for 6 to 18 months.
What are the risks of a medial branch block injection?
The risks of the procedure are very low. There is a small risk of infection, bleeding, or nerve injury. Considering the facet joints are on the outside of the spinal canal, the risk of nerve injury is exceptionally low. If the patient is on blood thinning medications, those should be ceased 5 to 7 days prior to the procedure. Check with your pain management doctor for the exact time frame.