Sacroiliac joint (SI) injections are used to diagnosis and treat pain emanating from
the sacroiliac joints. At the bottom of the spine, there is a triangle-shaped bone
known as the sacrum. The sacrum connects to the ilium bones of the pelvis via the
sacroiliac joints. There is cartilage and strong ligaments between the sacroiliac
joints. Patients with sacroiliac joint pain typically complain of pain at the low
back/buttock which may also radiate to the back of the thigh.
What is a sacroiliac joint injection?
A sacroiliac joint injection is an injection of local anesthetic and corticosteroid
into the sacroiliac joint. At Loudoun Spine and Rehabilitation, sacroiliac joint
injections are only performed under fluoroscopy (x-ray guidance) to ensure patient
safety, patient comfort, and to make sure the medication will be delivered to the
targeted area precisely. A sacroiliac joint injection procedure performed without
x-ray guidance is rarely successful in delivering the medication intra-articularly
(into the joint).
How is a sacroiliac joint injection diagnostic?
It is widely accepted that the sacroiliac joints can be a pain source when one experiences
low back/buttock pain. Unfortunately there is not a history or physical examination
finding or an imaging study finding which reliably diagnoses pain from the sacroiliac
joints. The local anesthetic component of the sacroiliac joint injection is the
“gold standard” for determining if a patient has pain from the joint. If the local
anesthetic relieves a significant amount of the patient’s low back/buttock pain,
this suggests their pain is emanating from the sacroiliac joint. Usually the patient
will asked to complete a Pain Diary for a few hours after the procedure to track
the amount of pain relief obtained from the injection. The patient does not need
to stay at our office to complete the Pain Diary. The Pain Diary can be completed
at home or work.
How can a sacroiliac joint injection be therapeutic?
If a patient has pain from the sacroiliac joints, the corticosteroid component of
the sacroiliac joint injection will reduce the inflammation at the joint and thus
reduce pain from the joint.
What is involved when having a sacroiliac joint injection?
Before an injection, patient history and targeted examination are performed, patient’s
spinal imaging if available is reviewed, risks and benefits of the procedure discussed,
and signed consent is obtained.
The patient is then taken to our fluoroscopy (x-ray) suite and will lie flat on an
x-ray table. Pillows will be used to position the spine for comfort as well as to
provide optimal positioning for performing the procedure. The skin overlying the
injection site is prepped (cleaned) in a sterile fashion and then sterile drapes
are placed around the prepped area.
The skin is then numbed with a local anesthetic. Under x-ray guidance a needle is
inserted. The needle is advanced under x-ray guidance to the targeted area. X-rays
pictures from different angles are used to ensure pin-point accuracy of the needle
tip. After the needle is placed properly, a small amount of contrast is injected
to ensure that the medication will go to the sacroiliac joint accurately as well
as to ensure patient safety. When optimal contrast flow is obtained, the medication
is injected. The medication consists of a corticosteroid and local anesthetic.
The procedure including preparation time on average requires 20-30 minutes. Afterwards,
a small Band-Aid is placed over the injection site, post-procedure instructions are
given, and then the patient is monitored for 5-10 minutes before going home
What is expected after the injection?
Typically the injection site will be numb for 1-2 hours. After that, the injection
site is usually sore. Intermittent application of an ice pack to area is recommended
if the area is sore. A temporary mild increase in a patient’s symptoms may occur
until the effect of the corticosteroid takes place (usually within 2-3 days). The
corticosteroid will reduce the inflammation causing the patient’s pain.
What about additional injections?
At Loudoun Spine and Rehabilitation, we will perform follow-up injections depending
on the outcome of prior injections. Often only one or two injections are required
to substantially reduce a patient’s pain symptoms.
How long will the injections last?
Although the effect of the corticosteroid is typically only a few weeks, the patient
may have pain relief for much longer. If the inflammation causing the patient’s
pain is significantly reduced, the pain may not come back.