Sacroiliac joint pain is increasingly recognized as a meaningful contributor to chronic lower back and buttock pain, yet it is sometimes underdiagnosed because its symptoms can resemble other spinal conditions. This overview explains what the sacroiliac (SI) joints are, common symptom patterns, and how physicians typically approach diagnosis and management.
What Are the Sacroiliac Joints?
The sacroiliac joints connect the sacrum (the triangular bone at the base of the spine) to the iliac bones of the pelvis, one on each side. These joints allow limited movement but play an important role in transferring load between the upper body and the legs. When these joints become a source of pain — whether from injury, degenerative changes, pregnancy-related ligament laxity, or altered biomechanics — the resulting symptoms are often referred to as SI joint pain or SI joint dysfunction.
What Symptoms Are Commonly Associated with SI Joint Pain?
Symptoms attributed to the sacroiliac joint can vary, but commonly reported patterns include:
- Pain localized to one side of the lower back or buttock, near the dimple of the pelvis
- Pain that may radiate into the posterior thigh, though usually not below the knee
- Discomfort worsened by prolonged sitting, standing on one leg, climbing stairs, or transitioning from sitting to standing
- A sensation of instability or "giving way" in the pelvis for some patients
Because these symptoms overlap considerably with facet joint pain, disc-related pain, and hip pathology, a physician evaluation is generally needed to help clarify the likely source.
How Do Physicians Typically Diagnose SI Joint Pain?
Diagnosis usually combines clinical history, a physical examination involving specific provocative maneuvers, and sometimes imaging to rule out other causes. Because no single physical exam test is considered fully definitive on its own, physicians often use a diagnostic SI joint injection — placing local anesthetic (and sometimes a corticosteroid) into or around the joint under imaging guidance — to help confirm whether the joint is a significant contributor to the patient's pain.
What Interventions Might Physicians Consider?
Management of confirmed SI joint pain is generally approached in a stepwise, multidisciplinary manner. Initial approaches often include physical therapy focused on pelvic stabilization, activity modification, and medication management under physician guidance. For patients with diagnostically confirmed SI joint pain that has not responded adequately to conservative measures, physicians may consider radiofrequency ablation of the sensory nerves supplying the SI joint (sometimes called lateral branch RF denervation) as a further option. INVAMED's Peta RFA System is designed to support this type of nerve-targeted radiofrequency application as part of a physician-directed care plan. All procedures carry risks, and suitability is determined individually.
Frequently Asked Questions
How common is the sacroiliac joint as a source of low back pain?
Commonly cited estimates suggest the SI joint is a meaningful, though frequently underrecognized, contributor to chronic low back pain in a subset of patients, which is part of why targeted diagnostic evaluation is often recommended.
Can SI joint pain be confused with sciatica?
Yes, referred pain patterns from the SI joint can sometimes mimic sciatica, though SI joint pain less commonly extends below the knee. A physician evaluation, sometimes supported by diagnostic injections, helps distinguish between these sources.
Is SI joint pain more common after pregnancy?
Ligament laxity and biomechanical changes during and after pregnancy are commonly discussed contributing factors to SI joint-related symptoms in some individuals, though a physician evaluation is needed to confirm the specific cause in any given case.
Related INVAMED Resources
- Peta Radiofrequency Ablation (RFA) System, Nerve
- Pain Management & Spine (Algology) products
- Contact INVAMED for Product Information
Medical Disclaimer: This article is provided for general informational and educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendation. It is not a substitute for consultation with a qualified healthcare professional. Product indications, availability, and regulatory status vary by country. Always refer to the official Instructions for Use (IFU) and consult a licensed physician for guidance specific to your situation. INVAMED devices are intended for use by trained healthcare professionals.