Last Updated on October 29, 2023
A sacroiliac joint injection is also called a sacroiliac joint block. It is primarily used either to diagnose or treat low back pain and/or sciatica symptoms associated with sacroiliac joint dysfunction.
Relevant Anatomy
The sacroiliac joint is an amphiarthrodial joint, formed between the auricular surfaces of the sacrum and the ilium.
Interosseous ligament, the anterior and posterior sacroiliac ligaments. Are the major stabilizers of sacroiliac joints.
Sensory innervation the dorsal side of SI joint comes from the dorsal root ganglions of L4 to S2and the ventral innervation originates from L1 to S2.
Indications of Sacroiliac Joint Injection
Indications for sacroiliac joint injection are –
- Diagnosis of the cause of pain suspected to be of sacroiliac origin
- Treatment of pain diagnosed to be of sacroiliac origin
Often the two are combined into one injection [First the diagnosis, then treatment]
It must be noted that the methodology involved in injection application is similar in both the cases and the difference is only of the material injected.
Diagnosis
A diagnostic sacroiliac joint injection is used to confirm a suspected diagnosis of sacroiliac joint dysfunction by anesthetizing the sacroiliac joint with local anesthetic (e.g. lidocaine) under fluoroscopy.
After the injection, the patient is asked to try and reproduce the pain by performing activities which are painful to him.
A relief of 75-80% for the normal duration of the anesthetic suggests a tentative diagnosis of sacroiliac joint dysfunction.
For confirmation, a second injection using a different anesthetic (e.g. Bupivicaine) is used in order to confirm the diagnosis.
If this second injection also results in 75-80% pain relief, then most likely, pain source is sacroiliac joint.
Pain Relief
For pain relief, the injection is performed using the same, except that anti-inflammatory medication (corticosteroid) is included in the injection to provide pain relief by reducing inflammation within the joint.
Contraindications
Absolute contraindications
- History of significant allergic reactions to injected solutions
- Local malignancy
Relative contraindications
- Congestive heart failure
- Uncontrolled diabetes mellitus
- Pregnancy
- Systemic or local infection at the site of a planned injection
- Bleeding disorder
- Patient on anticoagulants
In cases where patients take anticoagulants, the medications should be held for 7 days prior to the injection and for 24 hours after the injection.
Sacroiliac Joint Injection Procedure
After informed consent has been obtained, the patient lies face down on his or her stomach on the radiography table. A pillow might be placed under the hips for patient comfort.
Anxiolytics may be used in anxious patients.
The skin overlying the sacroiliac joint injection is cleansed using Povidine-Iodine or chlorhexidine solution.
The needle insertion site is often numbed using a local anesthetic.
The insertion of a single needle in the inferior aspect of the joint is preferred. Insert the needle in a medial-to-lateral direction.
The needle is advanced through the skin, capsule, and ligaments of the joint until it is introduced into the joint.
Approximately 1 mL of contrast is injected. It should outline the joint, which can be easily viewed under fluoroscopy
Two types of medications are typically injected:
For the diagnostic purpose, a local anesthetic (lidocaine or bupivacaine) is injected into the joint and pain relief is gauzed.
For treatment, a corticosteroid [admixed with anesthetic for initial pain relief] which may help reduce inflammation within the joint and relieve symptoms for a longer period [Several months to a year].
The patient is monitored for about 30 minutes for adverse/allergic reactions.
In either strategy [diagnosis or treatment], the patient’s pain level is assessed by having the patient perform activities that would usually provoke pain. The percentage of pain relief is documented.
At least 75 percent improvement of the patient’s painful activity-related symptoms. If a second diagnostic injection is positive, then the sacroiliac joint is considered the likely source of the patient’s painful symptoms.
Some authors recommend extra-articular or periarticular corticosteroid which has been found to provide significantly higher in various studies. This is said to be due to nociceptive fibers in The interosseous membrane and the surrounding ligaments.
This is significant if the pain is originating from soft tissues rather than joint itself.
As many as two-thirds of patients may have significant improvement of approximately 9 months duration with steroid injection. The pain may recur, and the injection can be repeated.
Complications of Sacroiliac Joint Injections
Adverse effects seen with sacroiliac joint injection are minimal.
The most commonly reported immediate adverse effect is a vasovagal reaction.
The common adverse effects are
- Temporary increase in pain
- Allergic reaction to a medication
- Bruising and/or soreness at the injection site.
- Infection
