Procedure Description
Sacroiliac joint fusion is a minimally invasive surgical procedure designed to treat chronic sacroiliac (SI) joint pain that has not responded to conservative treatments. The SI joints connect the base of the spine (sacrum) to the pelvis and play a critical role in absorbing shock and stabilizing movement between the upper body and legs.
The fusion procedure involves placing small implants or bone grafts across the SI joint to promote bone growth and stabilization, effectively eliminating abnormal motion that causes pain. Modern techniques allow for fusion through a small incision, often with minimal disruption to surrounding tissue and faster recovery times compared to open surgery.
What It Treats
SI joint fusion is typically recommended for:
Chronic SI joint dysfunction or instability
SI joint pain due to arthritis (sacroiliitis)
Post-traumatic SI joint pain
Pain after lumbar fusion (“adjacent segment disease”)
Leg or buttock pain originating from the SI joint
Common symptoms include:
Deep, aching lower back pain, often one-sided
Buttock pain, sometimes radiating into the hip or thigh
Pain worsened by sitting, standing, climbing stairs, or turning in bed
How It Is Performed
You will receive general or spinal anesthesia in an outpatient or short-stay surgical setting.
A small (1-2 Inch) incision is made near the buttock or lateral hip area.
Using fluoroscopic (X-ray) guidance, specialized instruments are advanced to access the SI joint with minimal soft tissue disruption.
The joint is prepared by removing cartilage and creating space for fusion.
Implants (usually titanium or cannulated screws) and/or bone graft material are placed across the joint to encourage bone growth and permanent fusion.
The incision is closed with sutures or surgical glue, and a sterile dressing is applied.
The entire procedure usually takes 30–60 minutes, and patients often go home the same day.
Pre-Procedure Instructions
Do not eat or drink for at least 6–8 hours before the procedure if anesthesia is planned.
Discuss your medications with your provider—blood thinners, anti-inflammatories, or diabetes medications may need to be adjusted.
Inform your provider if you:
Are pregnant or breastfeeding
Have allergies to implants, anesthesia, or antibiotics
Have a history of infection or poor bone healing
Arrange for a responsible adult to drive you home.
Wear loose, comfortable clothing to your appointment.
What to Expect After the Procedure
You may experience soreness or swelling at the incision site for a few days.
Pain relief often begins within weeks, with full results developing as the bone fusion matures over 3–6 months.
You will likely need to limit certain movements (like twisting or lifting) during the early recovery period.
Your provider may recommend physical therapy to restore mobility and strengthen surrounding muscles.
Most patients return to light activity within 1–2 weeks, with full recovery in 6–12 weeks, depending on activity level and healing.
Call your provider if you experience:
Fever or chills
Wound redness, drainage, or swelling
Severe or worsening pain
Numbness, tingling, or difficulty walking
Evidence
There are now two peer-reviewed prospective publications specifically evaluating the Catamaran SI Joint Fusion System, both from the ongoing MAINSAIL multicenter study. The results are encouraging, but the evidence base is still relatively small and lacks a randomized comparator.
The initial 2024 publication was a prospective, single-arm, multicenter post-market study involving 33 consecutive patients at six U.S. sites. At 6 months, 80% met the composite primary success endpoint. Mean SIJ pain VAS fell from 80.9 mm to 31.1 mm, and ODI improved from 51.9% to 29.6%. There were no reported device-related serious adverse events or surgical reinterventions, and 93.3% of patients reported being satisfied at 6 months.
A second peer-reviewed publication appeared in 2025, reporting 12-month clinical and CT outcomes. In the 12-month cohort, mean VAS decreased from approximately 78.8 to 23.0, and ODI decreased from 51.6% to 20.8%, both statistically significant. Independent CT review found bridging-bone fusion in 19 of 23 patients, or 83%, at 12 months. No serious device-related adverse events, reoperations, vascular injuries, or nerve injuries were reported.
Those numbers are clinically meaningful. A roughly 56-point VAS reduction and 31-point ODI improvement compare favorably with outcomes reported for established minimally invasive SI fusion techniques. However, I would interpret that comparison cautiously because MAINSAIL was not designed as a head-to-head trial.
The biggest limitation is the level of evidence. MAINSAIL is prospective and multicenter, which is substantially better than a retrospective case series, but it remains single-arm, relatively small, and industry-associated. There is currently no Catamaran-specific RCT comparing it against conservative therapy, iFuse, Rialto, LinQ, or another SI fusion system. The longest peer-reviewed Catamaran clinical outcome data Is 12 months.
Notable is 83% CT-confirmed bridging-bone fusion rate. That’s different from some posterior SIJ procedures where the evidence has historically emphasized pain improvement without convincing radiographic arthrodesis. Catamaran’s implant actually transfixes the sacrum and ilium and is intended to create true arthrodesis rather than simply placing an allograft within the ligamentous portion of the joint.
Lasting Stability and Relief from SI Joint Pain
At Parkview Spine & Pain, we offer minimally invasive sacroiliac joint fusion for patients suffering from persistent lower back and buttock pain due to SI joint dysfunction. This procedure can provide durable relief and improved quality of life when other treatments have failed.
👉 Schedule your consultation today to find out if SI joint fusion is right for you.