Condition · Sacroiliac Joint · Naples & Fort Myers FL
SI Joint Dysfunction
& Sacroiliitis
The sacroiliac joint is responsible for 15–30% of chronic low back pain — yet it is one of the most commonly missed diagnoses in spine care. Pain in the lower back, buttock, groin, and down the leg that worsens with position changes may not be a disc problem. It may be the SI joint. And the treatment is completely different.
"SI joint dysfunction is responsible for 15 to 30 percent of chronic low back pain — but it is not a diagnosis every surgeon believes in or looks for. The physical exam findings overlap with lumbar disc disease, and the imaging rarely shows the diagnosis directly. Patients spend years being told they have a disc problem, get a lumbar fusion, and wake up with the same pain. The SI joint was the source all along. Every patient with chronic low back pain should have the SI joint explicitly evaluated before any lumbar surgery is planned."
Dr. G. Katsevman, MD · Neurosurgeon & Spine SurgeonUnderstanding the diagnosis
What is SI joint dysfunction?
And why is it so often missed?
The sacroiliac (SI) joint connects the sacrum — the triangular bone at the base of the spine — to the iliac bones of the pelvis on each side. There are two SI joints, one on each side, and they bear the full load of the upper body, transferring weight and absorbing impact between the spine and the legs with every step.
When the SI joint becomes inflamed, degenerated, hypermobile, or hypomobile due to injury, arthritis, prior lumbar surgery, pregnancy, or trauma, it produces pain in patterns that mimic lumbar disc disease almost exactly. This is the central diagnostic problem. Because the SI joint can refer pain to the lower back, the buttock, the groin, and even down the thigh, it is routinely misidentified as a disc herniation, lumbar stenosis, or lumbar facet problem — and treated as such.
The consequences of misdiagnosis are serious. A patient with SI joint dysfunction who receives a lumbar fusion will often wake up with the same pain — because the fusion addressed a lumbar segment that was not the pain generator. The SI joint, still untreated, continues to produce symptoms. This is one of the most common causes of persistent pain after technically successful lumbar surgery.
Sacroiliitis specifically refers to inflammation of the SI joint, which can occur as part of degenerative SI joint disease, inflammatory arthritis (including ankylosing spondylitis and psoriatic arthritis), or as an isolated finding. The term is sometimes used interchangeably with SI joint dysfunction, though sacroiliitis has a more specific inflammatory connotation.
Why it’s missed — no single test confirms itStandard MRI and X-ray often appear normal in SI joint dysfunction. There is no single physical exam finding that reliably identifies it. Diagnosis requires a combination of clinical exam (provocation tests), patient history, and image-guided diagnostic injection.
Not every surgeon evaluates itSI joint dysfunction remains a contested diagnosis in some spine surgery circles. Surgeons who do not regularly diagnose and treat it may not include it in their differential for low back pain — meaning patients are never offered the evaluation.
Can coexist with disc diseaseSI joint dysfunction does not exclude lumbar pathology. Both can be present simultaneously — which is why each must be independently evaluated before surgery is planned for either.
Higher prevalence after prior lumbar fusionPatients who have had a prior lumbar fusion have a significantly elevated risk of developing SI joint dysfunction. The altered mechanics of a fused lumbar segment concentrate stress at the SI joint. Prior lumbar surgery is an important risk factor.
Common in women, post-pregnancy patientsHormonal ligament laxity during and after pregnancy can produce SI joint hypermobility and chronic pain. Women are affected at higher rates than men in many clinical series.
responsible for 15–30% of chronic low back pain
Based on articles retrieved from PubMed, a comprehensive review by Cohen et al. published in Expert Review of Neurotherapeutics found that sacroiliac joint pain affects between 15 and 30% of individuals with chronic, nonradicular low back pain — making it one of the most common sources of lower back pain overall. A separate review by Gartenberg et al. published in the European Spine Journal described SI joint dysfunction as an "under-recognized source of low back pain" requiring improved diagnostic methods. And a 2020 literature review by Martin et al. in the International Journal of Spine Surgery concluded directly that "clinicians should examine the SI joint and include SI joint pain in their differential diagnosis for low back pain patients." Despite this evidence, the SI joint is not included in the routine evaluation of many spine surgery practices — and patients continue to receive lumbar fusions for pain that originates in the SI joint.
Recognizing the condition
Symptoms of SI joint dysfunction —
what patients actually feel
The hallmark of SI joint pain is that it changes with position — particularly with transitions: sitting to standing, getting in and out of a car, rolling over in bed, climbing stairs. This positional sensitivity is a key clinical clue. The pain pattern is also distinctly one-sided in most cases.
Pain typically felt at or just below the beltline, on one side. Unlike lumbar disc pain which is often central, SI joint pain localizes to one side and rarely crosses the midline. The area directly over the SI joint — just medial to the posterior superior iliac spine — is often the focal point.
Pain radiating into the buttock on the affected side is extremely common and often the dominant complaint. The SI joint also refers pain into the groin — a feature rarely produced by lumbar disc disease — which is a particularly useful diagnostic clue. Groin pain with lower back pain should raise immediate suspicion for the SI joint.
The SI joint can refer pain into the thigh and even the knee — mimicking sciatica and lumbar radiculopathy. Unlike true radiculopathy, SI joint leg pain rarely reaches below the knee and does not follow a strict dermatomal distribution. However, the overlap with disc-related leg pain is significant and contributes to frequent misdiagnosis.
Worsening pain with transitions — sitting to standing, getting in or out of a car, rolling over in bed, standing from a low chair — is one of the most characteristic features of SI joint dysfunction. The joint is most stressed during these loading transitions. Patients often describe a moment of severe pain that then slightly eases once fully upright.
Difficulty lying on the affected side due to direct pressure on the SI joint. Sleep is frequently disrupted. Patients may find themselves repositioning repeatedly at night to find a comfortable position — one of the quality-of-life markers that distinguishes SI joint pain from other sources.
Long periods of sitting — at a desk, on a plane, at a dinner table — typically worsen SI joint pain as load compresses the joint. Prolonged walking also aggravates it. Patients often unconsciously shift their weight to the unaffected side when sitting. Pain relief with standing and movement is common.
How it’s diagnosed
Diagnosing SI joint dysfunction —
why it requires a specific evaluation
Standard lumbar MRI and X-ray do not diagnose SI joint dysfunction. The SI joint rarely shows diagnostic abnormality on routine spine imaging. Diagnosis requires a dedicated clinical and procedural evaluation — which many patients have never received.
Patients with SI joint dysfunction can almost always point with one finger to the area of maximum pain — just inferior and medial to the posterior superior iliac spine (PSIS). This localization pattern, described as the Fortin Finger Test, has high specificity for SI joint origin. If a patient consistently points to this exact area, the SI joint must be evaluated, regardless of what the lumbar MRI shows.
No single test reliably identifies SI joint pain, but a battery of three or more positive provocation tests significantly predicts response to SI joint injection. Standard tests include FABER (Flexion, ABduction, External Rotation), FADIR, distraction, compression, Gaenslen’s test, and the thigh thrust. Three or more positive provocation tests is a strong clinical indication to proceed to diagnostic injection.
X-rays, CT, and MRI are used to rule out other structural causes of pain — fractures, tumors, inflammatory arthritis visible on bone marrow edema — and to evaluate sacroiliac joint anatomy. A normal MRI does not rule out SI joint dysfunction. In degenerative SI joint pain, imaging is often unremarkable. The absence of MRI findings does not exclude the diagnosis.
The definitive diagnostic step is an image-guided injection of local anesthetic into the SI joint under fluoroscopic or CT guidance — ensuring the needle is accurately placed within the joint space. If pain is reduced by 50% or more after the injection, the SI joint is confirmed as the source or a major contributor to lower back pain. This is the accepted standard for SI joint diagnosis and a prerequisite for surgical candidacy.
Treatment pathway
From conservative care
to minimally invasive SI joint fusion
Treatment begins with conservative options and progresses toward surgery only when non-surgical options have failed to provide lasting relief. Surgery is not the first step — but when conservative care fails, minimally invasive SI joint fusion has strong evidence for durable pain relief and functional improvement.
- Physical therapy targeted at SI joint stabilization — distinct from standard lumbar PT
- SI joint belt to provide external compression and stability during activity
- Oral anti-inflammatory medications for acute flares
- Activity modification — avoiding prolonged sitting, asymmetric loading, high-impact activity
- Therapeutic SI joint injections — intra-articular corticosteroid, typically fluoroscopic-guided
- Peri-articular injections targeting the ligamentous structures around the joint
- Radiofrequency ablation (RFA) of the lateral sacral branches — provides relief lasting several months to over a year in appropriately selected patients; does not address underlying structural pathology
- Chiropractic manipulation in patients with hypomobility
- Small lateral incision — typically 2–3 cm, posterior to the greater trochanter
- Triangular titanium implants inserted across the SI joint under live fluoroscopy
- Same-day discharge in most patients at an ambulatory surgical center
- Durable relief confirmed at 1 and 2 years in randomized controlled trials
- Insurance-covered procedure through Medicare and most major insurers
The clinical evidence
What the data shows —
minimally invasive SI joint fusion outcomes
Based on articles retrieved from PubMed, a systematic review by Chang et al. published in the Spine Journal (2022) analyzed 40 studies including 2 randomized controlled trials and found consistent, durable evidence for the effectiveness of minimally invasive SI joint fusion. Every reviewed study in a separate 2020 literature review reported clinical benefit.
The randomized controlled trial data shows improvements in pain and function that are maintained at 1- and 2-year follow-up — not just acute post-operative relief. Opioid use was also reduced in the surgical group compared to conservative management. A separate review by Martin et al. in the International Journal of Spine Surgery noted that every reviewed study reported clinical benefit across multiple implant manufacturers and surgical approaches, with low complication rates overall.
Common questions
What patients ask
about SI joint dysfunction
How do I know if my lower back pain is from the SI joint and not a disc? +
The two conditions produce overlapping symptoms, which is exactly why SI joint dysfunction is so commonly missed. Several clinical features suggest SI joint origin rather than disc origin: pain that is clearly one-sided at or below the beltline (rather than central); groin pain on the same side (the SI joint commonly refers to the groin; lumbar discs rarely do); worsening with position transitions (sitting to standing, getting in or out of a car) rather than just with flexion or extension; and a normal lumbar MRI that does not explain the symptoms. However, these features are not definitive — the only way to confirm SI joint origin is a positive response to an image-guided diagnostic injection.
My surgeon says SI joint dysfunction isn’t a real diagnosis. What should I know? +
This is a real clinical phenomenon. The idea that SI joint dysfunction is not a legitimate diagnosis represents an outdated minority view, not current evidence. Based on articles retrieved from PubMed, the medical literature consistently documents SI joint pain as a source of 15–30% of chronic nonradicular low back pain, with validated diagnostic criteria (provocation testing plus image-guided injection) and strong randomized controlled trial evidence for minimally invasive surgical treatment. The Spine Journal, the European Spine Journal, and the International Journal of Spine Surgery have all published substantial literature confirming both the diagnosis and the efficacy of treatment. If your surgeon does not evaluate the SI joint, a second opinion from a surgeon who does is appropriate — particularly before any lumbar fusion is planned.
I had a lumbar fusion and still have the same pain. Could it be the SI joint? +
Yes — and this is one of the most important clinical scenarios in which SI joint evaluation is essential. Persistent pain after technically successful lumbar fusion is a well-documented problem, and the SI joint is one of the most common causes. Two mechanisms are at work: first, SI joint dysfunction may have been the actual pain generator before surgery and was simply never diagnosed; second, prior lumbar fusion itself increases stress on the SI joint by eliminating motion at the fused segment and redistributing it to the sacropelvic junction — a well-recognized cause of new or worsened SI joint pain after lumbar surgery. Every patient with pain persisting after lumbar fusion should have a dedicated SI joint evaluation before any additional lumbar surgery is considered.
What does the SI joint fusion procedure actually involve? +
Minimally invasive SI joint fusion is performed through a small lateral incision — typically 2–3 cm — posterior to the greater trochanter. Under live fluoroscopic guidance, triangular titanium implants are placed across the SI joint to stabilize it and eliminate abnormal motion. The implants engage the cortical bone of the ilium and sacrum and provide immediate mechanical stability while long-term bony fusion consolidates. Most patients are discharged the same day from an ambulatory surgical center. Weight-bearing is typically allowed immediately with gradual return to full activity. Full details of the procedure are on the SI joint fusion procedure page.
Does insurance cover minimally invasive SI joint fusion? +
Yes — minimally invasive SI joint fusion is covered by Medicare and most major commercial insurers when specific criteria are met: confirmed diagnosis by clinical examination and image-guided injection, failure of at least 6 months of conservative treatment, and appropriate imaging findings. Prior authorization is typically required. The practice manages insurance coordination for all patients. Coverage criteria vary slightly by insurer, and specific requirements are reviewed during the consultation.
Can SI joint pain go into the groin? I was told that’s a hip problem. +
Yes — groin pain is a well-documented referral pattern from the SI joint, and it is one of the most diagnostically useful features. The SI joint refers pain anteriorly into the groin, posteriorly into the buttock, and laterally into the hip area. This overlap with hip pathology is another reason SI joint dysfunction is commonly misattributed. Hip osteoarthritis, hip labral tears, and iliopsoas pathology also produce groin pain — but so does the SI joint. When a patient has groin pain with lower back pain, both the hip and the SI joint should be specifically evaluated before a diagnosis is assigned to either.
"The SI joint is responsible for 15 to 30 percent of chronic low back pain, and a meaningful proportion of patients recommended lumbar fusion have never had their SI joint evaluated. It is not a difficult evaluation — it takes provocation testing in the office and, if positive, a diagnostic injection. But if your surgeon doesn't believe in the diagnosis, it will never happen. The result is lumbar fusions performed for the wrong pain generator, and patients who wake up from technically successful surgery with the same pain they came in with."
Gennadiy (Gene) A. Katsevman, MD
Neurosurgeon & Minimally Invasive Spine Surgeon · Naples & Fort Myers FL
★★★★★ Hundreds of five-star reviews — Google, Healthgrades, WebMD
Naples Top Doctor — Neurosurgery 2024, 2025, 2026
Minimally invasive SI joint fusion — same-day discharge
TOPS™ · Disc replacement · Barricaid® · MIS laminectomy
PRP & BMAC biologics — optional intraoperative enhancements
Robotic navigation · EOS imaging · Intraoperative CT
Neuromonitoring on every fusion
No residents · No fellows · Every surgery performed personally
Fellowship — Barrow Neurological Institute under Dr. Juan Uribe
30+ peer-reviewed publications
Naples: 6101 Pine Ridge Road #101 · (239) 649-1662
Fort Myers: 8380 Riverwalk Park Blvd #320 · (239) 437-1121
SI Joint Dysfunction · Naples & Fort Myers FL · Telemedicine Available
If your lower back pain hasn’t
responded to treatment — has anyone checked your SI joint?
SI joint dysfunction is responsible for 15–30% of chronic low back pain and is frequently missed, particularly before lumbar surgery is recommended. Bring your imaging. Dr. Katsevman reviews it personally and evaluates each patient for SI joint dysfunction as part of a complete lower back pain workup.
6101 Pine Ridge Road #101, Naples, FL 34119
Fort Myers, FL 33919
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