Sacroiliac Joint Fusion: What It Is and What to Expect
Medically reviewed by Sumiran Racherla, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor provides Sacroiliac Joint Fusion?
An orthopedic surgeon, a doctor who operates on bones and joints, or a neurosurgeon, a doctor who operates on the brain and spine, performs sacroiliac joint fusion. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What it is
The sacroiliac joint, or SI joint, is where the sacrum and the iliac bones join. The sacrum is at the base of your spine. The iliac bones are the two large bones that make up the sides of your pelvis.
Fusion surgery holds the joint still, which removes the motion thought to cause pain in the joint. Surgeons can fuse the joint with open surgery or with a minimally invasive approach, which was developed in 2008 to address the shortcomings of open fusion.
Why a doctor might recommend it
The SI joint is a common cause of low back pain. People with SI joint problems typically have pain in the buttocks that may spread to the groin, the sides, and the upper legs. Doctors consider fusion for lasting, moderate to severe pain that limits daily life. They also look for no relief after at least six months of intensive care without surgery. Fusion is generally the next step when test results show that the SI joint is the source of the pain.
How to prepare
Before surgery, doctors need to confirm that the SI joint is the source of the pain.
- A CT or MRI scan can help rule out other causes, such as infection, fractures, and cancer.
- Your provider may want you to have an injection into the joint to find the exact spot of your pain.
- A CT scan of the pelvis taken before surgery helps the surgeon plan how to reach the joint.
What happens during it
In open fusion, a piece of bone is removed from the ilium to show the surface of the joint. The bone piece is then put into the joint space, which creates an environment for the joint to fuse. Plates with screws hold the fusion in place, and the cut is closed.
In the lateral minimally invasive approach, you are first placed face down under general anesthesia. The surgeon uses imaging, called fluoroscopy, to find the right starting point. The surgeon makes a small cut. Screws are placed across the SI joint, generally two or three. At the end, the surgeon rinses the site and closes the cut in layers.
Recovery
Recovery is faster and hospital stays are shorter with minimally invasive surgery than with open surgery. After open fusion, you cannot put weight on the affected side for three months or until a solid fusion is seen.
Contact your provider if you have sudden numbness or tingling in your lower back and hips. Also call if you have weakness or numbness in your legs. Also call if you have problems controlling your bowel or bladder. Also call if you have a fever. Call 911 or go to the emergency room if you have bleeding that will not stop, trouble breathing, chest pain or discomfort lasting two minutes or more, or fainting.
Risks and side effects
The lateral approach goes through the muscles of the buttock. This risks injuring nearby nerves and an artery. The most common reason for a second surgery after minimally invasive fusion is an implant in the wrong position. Screws in the wrong place have caused serious problems. These include lasting lower back pain, pinched nerves, nerve irritation, and loss of nerve function.
Problems reported after minimally invasive lateral fusion include more hip, back, and buttock pain. More serious problems, such as deep wound infection and pinched nerve roots, have also been reported.
Who performs it
An orthopedic surgeon or a neurosurgeon performs this surgery.
Common questions
What treatments do doctors try before SI joint fusion?
Doctors generally try measures such as pain medicines called NSAIDs, muscle relaxants, and physical therapy first. An injection into the SI joint can also be part of early diagnosis and treatment.
Can I put weight on the affected side after open SI joint fusion?
Not at first. After open fusion, you cannot put weight on the affected side for three months or until a solid fusion is seen.
How does a direct primary care or concierge doctor fit in?
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
Sources
- National Library of Medicine (PubMed Central) - Minimally invasive sacroiliac fusion: current insights and a comprehensive literature review
- National Library of Medicine (PubMed Central) - A Review and Algorithm in the Diagnosis and Treatment of Sacroiliac Joint Pain
- MedlinePlus - Sacroiliac joint pain - aftercare
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
