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Sacroiliac Joint Fusion (MIS SIJ)

Overview

What is MIS SIJ?

Sacroiliac (SI) joint fusion is a surgical procedure designed to stabilise the joint between the sacrum and ilium, which connects your spine to your pelvis. The minimally invasive (MIS) approach has become the preferred method for managing SI joint pain that does not improve with conservative treatments, reducing recovery time and tissue disruption compared to traditional open surgery.​

Who is it for?

If you have chronic lower back or buttock pain due to SI joint dysfunction—and have not found relief after six months of medications, injections, and physiotherapy—you may be considered for MIS SI joint fusion.

This procedure is suitable for people experiencing:

  • SI joint degeneration, arthritis or instability
  • Severe pain following trauma or after lumbar spinal fusion
  • Persistent pain not relieved by non-surgical management
  • Confirmed diagnosis with imaging and/or diagnostic injections

What the Procedure Involves

Here’s what to expect during minimally invasive SI joint fusion:

  • The procedure is performed under general anaesthesia; you will be positioned face down on the table
  • A small (less than 2-inch) incision is made over the affected joint, and muscles are gently separated (not cut)
  • Using fluoroscopy or computer navigation, the surgeon places guidewires across the SI joint for precision
  • Specialised tools prepare the joint space
  • One or more titanium implants are placed across the joint to promote fusion and stability
  • The incision is closed with sutures or staples, and a sterile dressing is applied
  • The operation typically takes less than an hour; most patients stay in hospital for one night​

Risks and Complications

While the minimally invasive technique reduces risk compared to open surgery, important risks can include:
Be aware of the following potential complications:

  • Infection at the surgical site
  • Bleeding or blood clots
  • Nerve injury leading to numbness or weakness in the leg
  • Failure of the bones to fuse (non-union), which may require further surgery
  • Implant complications (loosening, movement, misplacement)
  • Persistent pain or adjacent segment disease (stress on neighbouring joints or spine)
    Most complications are uncommon but will be discussed by your surgeon before surgery.

Recovery expectations and duration

Recovery from MIS SI joint fusion occurs in stages and is generally faster than with traditional open surgery. Here’s what most patients experience:

  • Walking (with assistance) can usually begin within 24 hours of surgery
  • Most patients go home the day after surgery
  • Crutches are often used for the first 6 weeks, with limited weight through the affected side during that period
  • Light daily activities can usually resume within 2–6 weeks, including cooking or light chores
  • Return to office work or driving is possible after about 2 weeks, if comfortable and not using strong pain medication
  • Physical therapy focuses on gentle mobility at first, then progressive strengthening
  • Full recovery—meaning return to most activities and maximal pain relief—often takes 2–6 months, and high-impact exercise is delayed until fusion and healing are confirmed​
    Your surgeon will schedule regular follow-up visits, often at 2 weeks, 6 weeks, 3 months, 6 months, and 12 months post-surgery, to monitor healing and function

FAQs

Will I feel the implant or notice changes in movement?
Most people do not feel the implant after healing, and movement of the pelvis is not usually noticed in day-to-day activities.

How successful is this procedure?
Most patients achieve significant, lasting pain relief and return to valued activities, particularly when rehabilitation instructions are closely followed.