A diagnostic medical branch nerve injection, also called a medial branch nerve block, is minimally invasive procedure that determines the cause and location of a patient’s back pain. Medial nerves stem from facet joints in the spine, and they carry sensory signals from these joints to the brain. If these nerves become damaged or diseased, they will begin sending pain signals to the brain, causing an array of symptoms such as pain, numbness, or tingling in the lower extremities. A medial branch block is used as part of a two-step diagnostic plan where the injection is administered first, then a subsequent procedure called radiofrequency neurotomy is considered for long-term pain relief. Radiofrequency neurotomy is performed on the patient after the success of the diagnostic medical branch nerve injection has been confirmed.
During a diagnostic medial branch nerve injection, the patient lies face down on a table with their neck or back exposed. Shortly thereafter, the physician cleanses the surgical site and injects a local anesthetic to numb the skin and surrounding tissues. Using X-ray guidance, the physician then directs a small needle over the medial branch nerves to inject a contrast dye. This injection helps confirm whether or not the medicine will cover the damaged medial branch nerves. Once the placement has been confirmed, an anesthetic and steroid medicine will be injected into each targeted nerve. The patient will be asked to report their pain levels after each injection. If the patient experiences significant pain relief immediately after the injection, then the physician can assume that particular facet joint is the source of the patient's pain. As soon as the patient has reported complete pain relief, the needle will be removed and a bandage will be placed over the injection site. Patients are then sent to a separate room to recover.
After the procedure, patients may experience partial or complete pain relief. This is due to the anesthetic, and the numbing medication should wear off within four to six hours. Patients will have their vitals monitored immediately after the procedure to rule out any post-procedural complications. After the patient returns home, he or she will be asked to take it easy for a day or two after the injection. If more than one injection was administered, the patient may be asked to take time off of work. It is difficult to predict how long an injection will last, but patients may experience pain relief that lasts several days, weeks, or months. While complications are rare, patients should report any signs of a fever, infection, swelling, redness, or increased pain to their Orthopedic and Wellness physician.