Sacroiliac (SI) joint fusion is a minimally invasive procedure that stabilizes the SI joint — the joint connecting the sacrum to the pelvis — when it is the confirmed source of chronic low back, buttock, and leg pain. Using a lateral approach through a small incision, implants are placed across the joint to eliminate painful motion and promote bony fusion.
What Is SI Joint Fusion?
The sacroiliac joint is a large, weight-bearing joint that connects the base of the spine (sacrum) to the pelvis (ilium) on each side. It absorbs significant forces during walking, standing, and transitioning between positions. SI joint dysfunction — whether from degeneration, ligamentous laxity, prior lumbar fusion that increases SI joint stress, or trauma — can cause chronic pain in the lower back, buttock, groin, and sometimes radiating into the upper leg, mimicking lumbar disc or hip pathology.
Minimally invasive SI joint fusion is performed through a small lateral incision with the patient lying on their side. Under fluoroscopic (X-ray) and CT-based guidance, a series of implants — typically titanium triangular or cylindrical implants — are precisely placed across the SI joint, spanning from the ilium into the sacrum. The implants provide immediate stability and create a scaffold for bone ingrowth, leading to solid fusion over 6–12 months. The procedure preserves the overlying gluteal musculature and avoids the large incisions of open SI joint procedures.
Accurate diagnosis is the most critical step. Because SI joint pain overlaps in presentation with lumbar disc disease, facet pain, hip pathology, and piriformis syndrome, Dr. Chavarria requires confirmation of the SI joint as the pain generator — typically through a diagnostic SI joint injection with fluoroscopic guidance. Significant pain relief (typically >75%) from a properly performed diagnostic injection is required before surgical planning.
Are You a Candidate?
- Patients with chronic SI joint pain confirmed by diagnostic SI joint injection (>75% pain relief)
- Patients with SI joint degeneration, dysfunction, or disruption causing daily back, buttock, or leg pain
- Patients with SI joint stress following prior lumbar fusion (adjacent joint phenomenon)
- Patients with sacroiliac joint disruption from trauma or ligamentous injury
- Patients who have failed conservative treatment including physical therapy, SI joint injections, and radiofrequency ablation
- Patients without active infection or severe osteoporosis that would compromise implant fixation
What to Expect
Pre-operative: Diagnostic workup includes a fluoroscopically-guided SI joint injection. MRI and CT are used to evaluate joint degeneration. X-rays assess pelvic alignment. The diagnosis must be confirmed by injection before proceeding.
Day of surgery: The procedure takes 45–75 minutes under general or spinal anesthesia. A 2–3 cm incision is made over the lateral buttock. Three implants are typically placed under imaging guidance. Most patients are discharged home the same day or after one overnight stay.
First 4 weeks: Partial weight-bearing with a walker or crutches for 2–4 weeks is typical to protect the implants during early bone healing. Activity is gradually increased. Pain at the incision site and some post-operative discomfort is managed with oral medications.
3–12 months: Most patients experience significant improvement in SI joint pain by 3 months as fusion progresses. Physical therapy focusing on core stabilization and gait retraining begins at 4–6 weeks. CT imaging may be used at 6–12 months to confirm fusion.
Why Choose Dr. Chavarria for Your SI Joint Fusion in Reno?
- Minimally invasive — small incision, no cutting of gluteal muscles
- Highly effective for confirmed SI joint pain — clinical studies show 75–85% patient satisfaction
- Same-day or next-day discharge for most patients
- Precise implant placement under dual fluoroscopic and CT-based guidance
- Durable long-term solution for a frequently overlooked pain generator
- Particularly effective for patients with increased SI joint stress after prior lumbar fusion