Sacroiliac (SI) joint fusion is often a successful surgery for those with chronic lower back pain due to SI joint dysfunction, including older adults. It may provide pain relief that lasts for 5 years.

If conservative treatment methods such as medications, exercises, and injections don’t help relieve lower back and pelvic pain, surgical treatments such as SI joint fusion may help.

Your sacrum and the ilium naturally form a joint, and this fusion procedure joins the two together.

Innovations in SI joint fusion allow doctors to perform the surgery using a minimally invasive approach. Keep reading to learn about how and for whom this procedure can help.

This is likely because your SI joint helps you bend and withstands pressure while doing so, transferring force and pressure from your lower back to your legs.

This leaves your SI joint vulnerable to stress and injury, which can lead to pain.

The goal of SI joint fusion is to reinforce your SI joint and help reduce pain. Besides pain relief, other benefits of an SI joint fusion may include:

  • a better quality of life
  • enhanced daily function
  • reduced disability

Not everyone will benefit from SI joint fusion, but it may be most effective for:

  • older adults who have chronic (long-term) symptoms of back pain due to SI joint dysfunction
  • people who haven’t had spinal surgery before

The surgery may be less effective for:

  • those who take opioids (pain medication) most of the time
  • those who smoke
  • those who have undergone previous spinal fusion

A doctor will carefully study your symptoms to determine the likelihood that the surgery will relieve your discomfort.

Surgeons can perform SI joint fusion using an open or minimally invasive approach.

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Illustration by Jason Hoffman

Open approach

The open surgical procedure involves:

  1. The use of general anesthesia, so you’ll be asleep.
  2. Your surgeon makes an incision that’s 7 to 8 inches (17.8 to 20.3 centimeters [cm]) in your lower back to expose your SI joint.
  3. Your surgeon removes a block of bone to access your sacrum’s cartilage-covered surface.
  4. Your surgeon removes the cartilage that’s over your sacrum.
  5. Your surgeon replaces the block of bone and uses plates and screws to fix it in place to help stabilize the joint.
  6. The surgeon irrigates (uses saline to clean) the surgical site to ensure there are no extra bits of bone or tissue. They then close the wound using sutures.

The entire procedure takes about 3 hours. You may need to stay in the hospital for up to 5 days after the operation.

Minimally invasive approach

Surgeons may opt to perform SI joint fusion as a minimally invasive surgery.

The steps for a minimally invasive SI joint fusion are similar to the open approach and may include:

  1. The use of general anesthesia.
  2. A surgeon makes a small, 3- to 5-cm (or smaller) incision on the side of your buttock.
  3. The surgeon dissects (cuts) through your gluteal (butt) muscles to access your ilium, or the upper portion of your pelvis.
  4. A surgeon uses a special guide pin to access your ilium and drill so implants can be passed toward your sacrum.
  5. A surgeon guides the instruments for implantation through the passage they created in your ilium and secures the implants using screws and pins.
  6. The surgeon irrigates (uses saline to clean) the surgical site to ensure there are no extra bits of bone or tissue. They then close the wound using sutures.

The procedure takes about 1 hour. You usually will be ready to go home the next day.

If SI joint fusion is performed in a minimally invasive fashion, surgeons typically encourage you to get up and walk around as soon as you’re able after surgery.

You may need an ambulatory assist device, such as a cane or crutches, to avoid excessive pressure on the operative site.

Surgeons typically recommend limiting weight-bearing activity, heavy lifting of more than 10 pounds (4.5 kilograms), and excessive bending at the waist for up to 6 weeks after surgery, no matter the type.

Some doctors may recommend avoiding these activities and movements for up to 12 weeks after surgery to ensure your bone and surgical implants heal properly.

A surgeon may recommend follow-up imaging about 6 months after surgery before you can return to full physical activity.

Adverse side effects aren’t usual following a SI joint fusion, but common risks of this procedure may include:

  • new-onset back pain in another location
  • trochanteric bursitis (hip pain)
  • infection
  • bone fracture
  • “nonunion,” or failure of the bone to heal

Other potential, but less common, side effects include:

  • bleeding
  • hematoma (collection of blood due to damage to blood vessels)
  • bruising
  • nerve pain
  • blood clots in your legs or lungs

The ability to perform the surgery in a minimally invasive fashion has helped improve outcomes and reduce serious effects, according to a 2019 study.

Medicare will typically cover SI joint fusion.

Other insurance providers also typically cover this surgery, but you may have to obtain precertification before undergoing it.

According to Medicare.gov, if the surgery takes place at an ambulatory surgery center, you may pay about $3,193. If the surgery is at a hospital outpatient department, you may pay around $1,834.

However, this price doesn’t include surgeon fees or additional procedures (if needed). Your costs may also vary based on your location and health needs.

How successful is SI joint fusion in relieving lower back pain?

While you may not experience total pain relief after SI joint fusion, people typically experience significant relief that lasts 5 years or more.

SI joint dysfunction commonly contributes to lower back pain.

SI joint fusion performed with a minimally invasive approach has improved outcomes and reduced recovery times.

If you experience significant lower back pain that conservative measures haven’t helped, you may want to talk with a doctor about this potential treatment approach.