Sacroiliac Joint Injection
Sacroiliac Joint (SIJ) injections are commonly used to determine what is causing back pain. SI joint injections are primarily diagnostic injections, meaning that they help your doctor determine the cause of your back pain but may not provide you with any long-term relief from the pain. These injections eliminate pain temporarily by filling the SI joint with an anesthetic medication that numbs the joint, the ligaments, and joint capsule around the SI joint. If the SI joint is injected and your pain goes away for several hours, then it is very likely that the joint is causing your pain. Often long acting cortisone like medications are used to extend duration of pain control.
What parts of the body are involved?
At the lower end of the spine, just below the lumbar spine lies the sacrum. The sacrum is a triangular-shaped bone that is actually formed by the fusion of several vertebrae during development. The sacroiliac (SI) joint sits between the sacrum and the iliac bone - this is why it is called the sacroiliac joint. You can see these joints from the outside as two small dimples on each side of the lower back at the belt line. The SI joint is one of the larger joints in your body. The surface of the joint is wavy and fits together similar to the way two gears fit together. Very little motion occurs in the SI joint. The motion that does occur is a combination of sliding, tilting and rotation. The most the joint moves in sliding direction for couple of millimeters, and it may tilt and rotate only two or three degrees. The SI joint is held together by several large and very strong ligaments. The strongest ligaments are in the back of the joint outside of the pelvis. Because the pelvis is a ring, these ligaments work somewhat like the hoops that hold a barrel together. If these ligaments are torn, the pelvis can become unstable. This sometimes happens when a fracture of the pelvis occurs and the ligaments are damaged. Generally, these ligaments are so strong that they are not completely torn with the usual injury to the SI joint. The SI joint hardly moves in adults. During the end of pregnancy as delivery nears, the hormones that are produced cause the joint to relax. This allows the pelvis to be more flexible so that birth can occur more easily. Multiple pregnancies seem to increase the amount of arthritis that forms in the joint later in life. Other than the role the joint plays in pregnancy, it does not appear that motion is important to the function of the joint. The older one gets, the more likely that the joint is completely ankylosed - completely stiffened with no movement at all. It appears that the primary function of the joint is to be a shock absorber and to provide just enough motion and flexibility to lessen the stress on the pelvis and spine.
What does my physician hope to achieve?
If your doctor is recommending a SI joint injection, then he/she is trying to determine if one or both SI joints are the cause of your back pain. This type of injection is primarily a diagnostic injection. The injection may only help your pain temporarily, sometimes just for a few hours. Once your doctor is sure that it is the SI joint causing your pain, other procedures may be recommended to reduce your pain for a longer period of time. During a SI joint injection, the medications that are normally injected include an anesthetic and cortisone. The anesthetic medication (such as novocaine or lidocaine) is the same medication used to numb an area when you are having dental work. The medication causes temporary numbness lasting one hour to six hours, depending on which type of anesthetic is used. Cortisone is an extremely powerful anti-inflammatory medication and when this type of medications are injected into a painful, inflamed joints, they can reduce the inflammation and swelling. Reducing the inflammation reduces pain. If cortisone like medications are also injected into the joint at the same time, you may get several weeks' to months worth of relief from your pain. This can allow you to get started in a physical therapy program, strengthen the muscles, and begin normal movement again. When the cortisone wears off, the pain may not return.
How will I prepare for the procedure?
Your doctor may tell you not to eat or drink upto four hours before the procedure. This means no coffee, no tea, no juice - not anything. You may take your usual medications with a small amount of water. Check with your doctor if you are unsure what to do. You should tell your doctor if you are taking any medications that thin your blood or interfere with blood clotting. The most common blood thinner is coumadin, other medications also slow down blood clotting are Aspirin, Ibuprofen, Advil, Aleve, Motrin and nearly all of the other anti-inflammatory medications. Medications used to prevent strokes, such as Plavix, can also affect blood clotting. These medications usually need to be stopped seven to tend days prior to the injection. Be sure to let your doctor know if you are on any of these medications.
What happens before treatment?
The doctor who will perform the injection will review your medical records and imaging studies to plan for the best location for these injections. Patients who are taking aspirin or blood thinners may need to stop taking the several days before the SIJ injection, doctor will provide specific instructions. Discuss any medications with your doctors, including the one who prescribed them and the doctor who will perform the injection. The injection is usually performed in an outpatient procedures suite that has access to fluoroscopy. You will need make arrangements to have someone drive you to and from the office or outpatient center the day of the injection.
What happens during treatment?
Before your injection, you will be asked to sign consent forms, list medications you are taking, and list any allergies to medications. Procedure may last 15-30 minutes followed by a recovery period. Patients remain awake for these procedures. Sedatives can be given to help lessen anxiety. The patient will be lying face down on the table, will receive a local anesthetic, which will numb the skin before the injection is given. If IV sedation is used, your blood pressure, heart rate and breathing will be monitored during the procedure. With the aid of a fluoroscope (a special X-ray), the doctor will direct a hollow needle through the skin and muscles of your back into the SIJ joints or next to the sensory nerves that carry pain away from the inflamed SI joint(s). Fluoroscopy allows the doctor to watch the needle in real-time on the fluoroscope monitor to make sure that the needle goes to the specific facet joint. Contrast agent may be injected into the SI joint(s) to confirm correct needle position. Some discomfort may occur, but patients typically feel more pressure than pain. After the needles are confirmed to be in correct position, the doctor will inject mixture of local anesthetic and corticosteroid medication into your SI joint(s). The needle is then removed.
What happens after treatment?
Most patients can walk immediately after the procedure. After being monitored for a short time, you can usually leave the office or suite. Someone must drive you home. Typically patients will resume full activity the next day. If soreness around the injection site is present the following day, it may be relieved by using ice and taking mild pain medications such as Tylenol. The doctor’s office may want to follow up with you 7 to 14 days after the procedure to assess your response to this injection. You may be provided a diary to record your response to this procedure. You may notice a slight increase in pain after the numbing medicine wears off and before the corticosteroid medication starts to take effect. If discs are the source of pain, you may begin to notice pain relief in two to five days after the injection. If there is no improvement after 10 days, a second injection may be given. If after three injections you experience no or a little pain relief, then it is unlikely that you will benefit from more injections. Additional diagnostic tests may be needed to accurately diagnose your pain.
What are the risks?
The potential risks associated with inserting the needle include bleeding, infection, allergic reaction, headache, and nerve damage (rare), corticosteroid medication induced side effects such as weight gain, water retention, flushing (hot flashes), mood swings or insomnia, and elevated blood sugar levels in diabetics. These usually resolve within 3 days. Patients who are being treated for chronic conditions (e.g. heart disease, diabetes, rheumatoid arthritis, or those who cannot temporarily discontinue anti-clotting medication) should consult their personal physician for a risk assessment. With few risks, SI injections are considered an appropriate nonsurgical treatment for some patients. Like most procedures where medications are injected, there is always a risk of allergic reaction. The medications that are commonly injected include lidocaine, bupivicaine, radiographic dye, and cortisone. Allergic reactions can be as simple as developing hives or a rash. They can also be life threatening and restrict breathing. Most allergic reactions will happen immediately while you are in the procedure room so that help is available immediately. Most reactions are treated and cause no permanent harm. You should alert your doctor if you have known allergies to any of these medications. Any time a needle is inserted through the skin, there is a possibility of infection. Before any injection is done, the skin is cleansed with a disinfectant and the health care provider doing the injection uses what is called sterile technique. This means that the needle and the area where the needle is inserted remains untouched by anything that is not sterile. The provider uses sterile gloves. Infections can occur just underneath the skin, in a muscle, or in the SI joint. You should watch for signs of increasing redness, swelling, pain, and fever. Almost all infections will need to be treated with antibiotics. If an abscess forms, then a surgical procedure may be necessary to drain the pus in the abscess. Antibiotics will also be necessary to treat the infection.
What if the pain increases?
Not all injections work as expected. Sometimes, injections cause more pain. This may be due to increased spasm in the muscles around the injection. The increased pain is usually temporary, lasting a few hours or a few days. Once the medication has a chance to work, the injection may actually perform as expected and reduce your pain. Increased pain that begins several days after the injection may be a sign of infection. You should alert your doctor if this occurs.