Sacroiliac (SI) joint dysfunction is a frequently overlooked cause of low back and buttock pain, arising from the joint that connects the spine to the pelvis. Because its symptoms overlap with lumbar disc and hip problems, accurate diagnosis is essential — and when confirmed, SI joint pain responds well to targeted treatment including minimally invasive fusion.
What are the symptoms?
- Pain in the lower back and buttock, often on one side, that may radiate into the groin or upper thigh
- Pain that worsens with prolonged sitting, standing, climbing stairs, or transitioning from sitting to standing
- A feeling of instability or 'giving way' in the pelvis or lower back
- Pain when putting weight on one leg or lying on the affected side
- Symptoms that mimic sciatica but typically do not extend below the knee
- Tenderness directly over the SI joint at the back of the pelvis
What causes it?
- Degeneration: Age-related wear of the SI joint cartilage and ligaments
- Prior lumbar fusion: Fusing the lumbar spine increases mechanical stress on the SI joints, a common cause of new SI pain after back surgery
- Pregnancy and childbirth: Hormonal ligament laxity and pelvic changes can destabilize the joint
- Trauma: A fall onto the buttock or a motor vehicle accident can disrupt the joint
- Leg-length discrepancy or gait abnormality: Asymmetric loading stresses one SI joint over time
How is it diagnosed?
SI joint dysfunction is challenging to diagnose because its symptoms overlap with lumbar and hip conditions. Diagnosis begins with a focused physical examination using provocative maneuvers that stress the SI joint. The definitive diagnostic test is a fluoroscopically-guided SI joint injection — if numbing the joint produces significant pain relief (typically greater than 75%), the SI joint is confirmed as the pain source. MRI and CT rule out other causes and assess the degree of joint degeneration.
Your Non-Surgical Roadmap — Surgery Is the Last Step
Most patients with this condition get better without surgery. Here's the path Dr. Chavarria follows before an operation is ever on the table:
- 1
Start conservative
Physical therapy, activity changes, anti-inflammatory or nerve medication, and time — the first line for nearly every spine condition.
- 2
Add targeted relief
If symptoms persist, image-guided injections (epidural or nerve blocks) can calm inflammation and pinpoint the source of pain — often avoiding surgery entirely.
- 3
Re-evaluate together
Dr. Chavarria reviews your progress and imaging with you, honestly, and explains exactly where you stand — no pressure, no rush to the OR.
- 4
Surgery — only if it's truly the best option
Reserved for severe or worsening nerve compression, instability, or when conservative care has had a fair chance. When it is right, you'll understand why and what to expect.
Treatment Options in Reno, NV — Conservative Care First
Most SI joint dysfunction improves with conservative care — physical therapy targeting core and pelvic stabilization, anti-inflammatory medications, SI joint steroid injections, and radiofrequency ablation of the nerves supplying the joint. When the SI joint is confirmed as the pain generator and conservative measures fail, Dr. Chavarria performs minimally invasive SI joint fusion: titanium implants are placed across the joint through a small incision to eliminate painful motion and promote fusion. This is particularly valuable for patients who developed SI joint pain after a prior lumbar fusion.
Treatment Procedures
SI Joint Fusion
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.
Learn More →Lumbar Spinal Fusion (TLIF/PLIF)
Lumbar spinal fusion permanently connects two or more vertebrae together, eliminating painful motion at an unstable or severely degenerated spinal segment. Techniques such as TLIF (Transforaminal Lumbar Interbody Fusion) and PLIF (Posterior Lumbar Interbody Fusion) restore disc height, decompress the nerve, and stabilize the spine — and can be performed with minimally invasive techniques through small incisions.
Learn More →