Lower Back Pain
Sacroiliac Joint Pain
Pain arising from the sacroiliac joint, where the base of the spine meets the pelvis
Evidence: Well-Supported — ASPN 2024: Level I · Grade B*
CAUSES
- Wear-and-tear degeneration of the SI joint
- Pregnancy-related ligament laxity
- Trauma
- Asymmetric loading after a prior lumbar fusion
- Prolonged standing or repetitive twisting
SYMPTOMS
- One-sided low back or buttock pain, often just below the belt line
- Pain aggravated by standing up from sitting, or transitioning positions
- Pain with stairs or standing on one leg
- Occasional pain radiating into the back of the thigh
IMAGING
X-ray or CT can show joint degeneration in advanced cases, but the best diagnostic test is an injection of local anesthetics directly into the joint showing temporary pain relief.
CAN PRP HELP?
In patients who’ve had a positive diagnostic block confirming the SI joint as the pain source, PRP appears to offer longer lasting relief compared to a corticosteroid injection.
Leukocyte Preparation: Leukocyte-Poor
Dosing: Single or Short Series
ASPN 2024 CONSENSUS GUIDELINE
ASPN grades this Level I, Grade B — one of the stronger ratings in the whole guideline. The asterisk matters: this evidence, like all of ASPN’s spine indications, was built almost entirely under fluoroscopic (X-ray) guidance for reliable needle-tip confirmation inside the joint. The guideline is explicit that ultrasound-only guidance for the SI joint hasn’t been validated the same way. An ultrasound-guided injection here can still be a reasonable clinical choice, but it’s technically a different procedure than the one this Grade B evidence was built on — worth discussing directly if this is being considered.
Sources: D’Souza et al. (ASPN Consensus), Journal of Pain Research, 2024 · Rothenberg et al., Regenerative Medicine, 2021 · Burnham et al., Pain Medicine, 2020
FREQUENTLY ASKED QUESTIONS
How do you confirm the SI joint is causing my pain?
The most useful test is an image-guided diagnostic injection of numbing medication directly into the joint. If that relieves the pain, it confirms the SI joint as the source. X-ray or CT can show degeneration in more advanced cases, and MRI helps rule out inflammatory sacroiliitis or a lumbar spine cause.
Does SI joint injection need to be done under X-ray guidance rather than ultrasound?
ASPN’s Level I, Grade B evidence was built almost entirely under X-ray guidance for reliable needle-tip confirmation inside the joint. Ultrasound-only guidance hasn’t been validated the same way. It can still be a reasonable clinical choice, but it’s technically a different procedure than the one this evidence was built on.
How does PRP compare to a steroid injection for SI joint pain?
In patients with a positive diagnostic block confirming the SI joint as the pain source, PRP appears to offer more durable relief than a corticosteroid injection.
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