Overview of Sacroiliac Joint Injection
Sacroiliac (SI) joint pain is a frequent reason for lower back pain. Research shows between 10% to 27% of general lower back pain could be linked to pain in the SI joint. This pain might occur with or without pain in your legs. Problems with the SI joint can occur due to degenerative conditions or imbalances between the SI joints. There’s a higher chance of experiencing SI joint pain as you age or if you have issues such as leg length discrepancies, inflammatory arthritis, are pregnant, have had trauma, or have a history of spine surgery.
Classic SI joint pain is usually experienced as pain below the fifth lumbar vertebra (the lowest part of your lower back). Certain physical examination techniques, such as the FABER, Gaenslen’s, and compression tests, can bring out pain resulting from issues with the SI joint. If both your SI joints are painful and the pain is symmetrical, it could indicate inflammatory conditions such as ankylosing spondylitis, a type of arthritis that affects your spine.
If needed, an SI joint injection can help diagnose and treat SI joint pain. This procedure involves placing a local anesthetic or a mixture of local anesthetic and corticosteroids directly into the SI joint. Once this provides long-lasting and sufficient pain relief, you can return to your normal activities or begin a physical therapy program.
Anatomy and Physiology of Sacroiliac Joint Injection
The human body contains two sacroiliac (SI) joints, located where the ilium (part of the hip bone) meets the sacrum (the triangular bone at the bottom of the spine) on each side of the body. These joints are unique in that they have features of both ‘moving’ (diarthrosis) and ‘immovable’ (synarthrosis) joints. A capsule of ligaments (tough, flexible tissues) surrounds these joints, helping to connect the sacrum and ilia.
During pregnancy, a hormone named relaxin is released which can cause these ligaments to loosen. However, it’s important to note that understanding about how the nerves in the SI joint work is still unclear. Some say that the nerve fibers that create the feeling of pain for the joint come from certain nerves that come out from the spinal cord.
While the main job of the SI joints is to provide stability to the body and minimize the forces coming from the legs, they do have a small amount of movement. Research has shown that they can move around 2 degrees in all directions.
The SI joints can move in a few different ways. The joint can tilt forwards (anterior) and backwards (posterior) on the sacrum (innominate tilt), There’s also a motion called ‘nutation’ where the sacrum moves forwards and downwards, while the tailbone (coccyx) moves backwards compared to the ilium. The opposite motion, called ‘counternutation’, happens when the sacrum moves backwards and upwards, while the tailbone moves forwards relative to the sacrum.
Why do People Need Sacroiliac Joint Injection
If a person is experiencing pain in the sacroiliac (SI) joint area, doctors may decide to use a method known as an SI joint injection to both identify and treat the source of the discomfort. The sacroiliac joint connects the lower spine and the pelvis, and can sometimes cause pain in the lower back or legs.
Before administering an SI joint injection, doctors will typically talk to the patient about their symptoms, examine their physical health, and perform special tests to determine the cause of the pain. Generally, if a patient reacts positively to three or more specific tests geared toward identifying SI joint pain, it’s a good indication that an SI joint injection should help.
During the diagnostic part of the SI joint injection, an anesthetic (a substance that blocks feeling) is injected into the SI joint. If this results in a 75% reduction in pain when the patient moves in ways that previously caused them discomfort, and this reduction lasts while the anesthetic is active, then the patient can be diagnosed with SI joint dysfunction.
For treatment, doctors combine a local anesthetic (meaning it only affects a specific area) with a corticosteroid medication, which is used to lessen pain and inflammation. This combined injection is given in the SI joint to help manage pain. There are two methods for the injection, either inside the joint (intraarticular) or around the joint (periarticular). Recent studies suggest that injections inside the joint might be better than those around it for relieving pain.
When a Person Should Avoid Sacroiliac Joint Injection
There are certain cases where injections into the sacroiliac (SI) joint, which connects the spine to the hip, cannot be done. These cases are:
– When the patient has experienced or knows they are allergic to cortisone injections. Cortisone is a type of medicine often used to reduce inflammation.
– If a patient has a local cancerous tumor.
There are other situations where the injections should be carefully considered, such as:
– If the patient has a condition causing issues with blood clotting, or if they are currently using or have recently used medication to thin their blood.
– If a patient is pregnant.
– If a patient has a systemic infection, septic joint, or osteomyelitis. These are conditions that involve severe infection in the body, joint or bone.
– If a patient has Type II Diabetes and has had problems in the past with controlling their blood sugar levels.
Equipment used for Sacroiliac Joint Injection
In simpler terms, doctors use specific tools to perform a lower back (SI joint) injection procedure under the guidance of a special X-ray device called a fluoroscopic C-arm. They use local anesthetics such as lidocaine or bupivacaine to numb the area and minimize discomfort during the procedure. Other medications include corticosteroids, which have anti-inflammatory properties and help reduce swelling and pain. It might be familiar names like triamcinolone, methylprednisolone, betamethasone, or dexamethasone.
Other important tools in this procedure include a contrast solution, which is a special dye used to help doctors see the joint and surrounding tissues clearly on the X-ray. The doctor also uses sterile gloves and drapes and a germ-killing solution called betadine to maintain cleanliness and prevent infection. The injection is typically delivered using a long, thin needle (25-gauge, 5-inch, styletted spinal needle). In cases where the joint is worn out or hardened, a slightly larger needle (22-gauge) might be used.
Who is needed to perform Sacroiliac Joint Injection?
The medical team doing your treatment might include a doctor or another medical provider like a Physician Assistant, Nurse Practitioner, or medical trainee (like a Resident or Fellow). Also, there will be an assistant and a specialist operator who manages a piece of equipment called a Fluoroscopic C-arm, which helps the doctors see into your body. All these team members know how to handle any unexpected issues that might happen during your treatment. If you’re getting a treatment that uses a CT scan to guide the injection into your body, a CT technician is included in the team. This technician’s job is to capture the CT scan images which will help your doctor with the treatment.
Preparing for Sacroiliac Joint Injection
Before a medical injection can take place, it’s crucial that the patient fully understands the risks and benefits involved. This detailed discussion ensures the patient’s consent is knowledgeable and informed. Doctors use a process known as ‘time-out’ to confirm the patient’s identity and the exact location for the injection. During the procedure, the patient is asked to lay face down, and at this point, the doctor can begin to identify the specific joint where the injection will be made.
How is Sacroiliac Joint Injection performed
In a procedure called fluoroscopic guidance, a doctor or specialist uses special imaging tools to look inside your body and guide their actions. This is often used when injecting medication or other substances into a specific part of your body. For the procedure under discussion, you will most likely lie flat on your stomach with a pillow under your lower stomach area. This position helps your doctor see a small part of your pelvis, known as the ‘sacroiliac (SI) joint’, more clearly. An imaging tool called a C-arm is used first to help line up pictures of the lower part of this joint. The area is then cleaned and the doctor uses this fluoroscope to guide a needle to the exact spot in the SI joint. You may feel a slight pop when the needle reaches the right spot.
Once the needle is in place, a small amount of a substance known as contrast is injected into the joint. This substance helps to highlight the SI joint on the images, confirming that the needle is in the right place. After that, the actual treatment fluid is injected. The right amount of fluid varies, but in general, the doctor will stop injecting when they feel resistance, see the fluid leaking out of the joint, or reach a total of 2.5 ml.
A similar procedure called CT-guidance is also used. Here, you also lie flat on your stomach and a CT scan is done first to map out the path to the SI joint. This path is then marked on the skin which is also cleaned to keep things sterile. A local anesthetic is used to prevent pain, and a fine needle is inserted into the lower, back part of the SI Joints, again guided by the CT images. After the needle is confirmed to be in the right place, a mixture of medications is injected into the joint. The needle is then removed, and pressure is applied to stop any bleeding.
These procedures are very precise to make sure the medication gets exactly where it is needed. This, and the use of local anesthetic, helps to minimize any discomfort you may feel during the procedure.
Possible Complications of Sacroiliac Joint Injection
A systematic review has found that only a small portion of patients might experience immediate temporary reactions like a fainting or feeling of faintness (known as a vasovagal reaction) after a certain treatment. The most common side effects include increased pain and soreness.
However, there are a few rare but serious complications that could potentially occur. These include injury to the nerves, unintended injection into the spine’s holes (or foramina) through which nerves pass, formation of a blood clot within a blood vessel (hematoma), weakness in the sciatic nerve (sciatic palsy), inflammation of the membranes surrounding the brain and spinal cord (meningitis), a collection of pus (abscess), and a full body infection. There have also been isolated reports of a bacterial infection in the sacroiliac joint (pyogenic sacroiliitis) and a case of herpes simplex, a viral infection.
There could also be risks associated with the use of steroids and local anesthetics – substances used to reduce pain. Additionally, studies have reported that in around 10% of cases, the technique used for the treatment might not be successful.
What Else Should I Know About Sacroiliac Joint Injection?
When suspecting pain in the sacroiliac joint (SI joint, the joint connecting your spine and hip), doctors often use a technique called “SI joint blocks” to diagnose and treat the pain. This involves inserting a needle into the joint and injecting medication to decrease inflammation and relieve pain. While it’s possible to perform these injections without using an imaging technique to guide the needle, studies have shown that the chance of successfully reaching the target area in the SI joint is only 12% to 22% without guidance.
Different imaging techniques, like an ultrasound or a CT scan, can be used to guide the needle. However, fluoroscopy (a type of X-ray imaging that shows real-time moving images of the inside of your body) is generally the preferred method. This is because it not only ensures correct placement of the needle, but it also allows doctors to visualize the spread of the medicine from the joint to nearby areas in the body, which cannot be seen as effectively with CT scans.
After an SI joint injection, if the patient experiences more than a 75% decrease in pain when performing movements that were previously painful, this therapy is considered successful. Some doctors might also use a controlled local anesthetic block to confirm success and eliminate false positive results.
Evidence shows that SI joint injections can help significantly in relieving chronic low back pain or pain in the lower extremity (below the fifth bone in your lower spine, called the “L5 vertebra”). In one study, patients with SI joint dysfunction and a particular kind of joint disease, spondyloarthropathy, experienced pain reduction for more than 6 weeks in two-thirds of the cases after an SI joint injection treatment.
If the pain is not relieved adequately through this injection therapy, doctors might consider other options, such as prolotherapy (where an irritant solution is injected into the joint to stimulate healing), radiofrequency ablation (a procedure that uses radio waves to decrease pain signals), viscosupplementation (injecting a fluid into the joint to improve its functioning), or minimally invasive SI joint fusion (a surgical procedure where the SI joint is fused to minimize its movement and relieve pain).
