Sacroiliac Joint Injection is Medically Indicated
This 52-year-old female with sacroiliitis meets all medical necessity criteria for a repeat left sacroiliac joint injection, and the procedure should be authorized and performed. 1, 2
Diagnostic Criteria - Fully Met
The patient satisfies the rigorous diagnostic requirements for SI joint-mediated pain:
Pain duration >3 months: Patient has chronic sacroiliitis with pain persisting beyond the required threshold 1, 3
Positive Fortin Finger Test: Documented positive Fortin's Point, indicating ability to localize pain to the posterior superior iliac spine region 1, 2
≥3 of 5 provocative maneuvers positive: Patient demonstrates 4 of 5 positive tests (Fortin's Point, SI Joint Compression, SI Joint Distraction, Patrick's/FABER sign, and Thigh Thrust on the left), which provides 94% sensitivity and 78% specificity for SI joint pain diagnosis 4, 1, 3
Conservative Treatment Requirements - Fully Met
The patient has exhausted appropriate conservative management:
6 weeks of physical therapy/home exercise program: Documented completion of PT and ongoing home exercise regimen 1, 2
Pharmacotherapy trials: Currently on celecoxib 200mg daily, pregabalin 150mg BID, methocarbamol 500mg TID PRN, and acetaminophen as needed 5
Activity modification: Patient has attempted multiple conservative modalities including chiropractic care 1
Previous Response Justifies Repeat Injection
The patient's prior injection history strongly supports medical necessity for repeat treatment:
7/20/23 Left SI Joint Injection: Achieved 50% pain relief 2, 6
6/17/21 Bilateral SI Joint Injections: Achieved 80% pain relief 2
Most recent injection (4/23/2025): Patient reported >50% sustained improvement in pain with enhanced ability to walk, stand, sleep, work, and lift for 3 months 2
According to Spine Intervention Society guidelines, repeat injection is appropriate when there was at least 50% relief for at least 2 months after the first injection 2. This patient exceeded this threshold with 3 months of significant functional improvement.
Imaging Adequately Rules Out Alternative Diagnoses
While the policy requires ruling out other causes of low back pain, the available imaging is sufficient:
12/18/2019 X-ray: Shows only mild chronic degenerative changes of bilateral SI joints 3
4/10/2021 X-ray lumbosacral spine: Demonstrates mild spondylosis only 3
4/19/2021 MRI thoracic spine: No acute changes, very mild spondylosis 3
Critical point: The patient's physical examination is negative for radicular pain, negative straight leg raise, and lacks neurogenic claudication, effectively ruling out significant lumbar disc herniation, spinal stenosis, or nerve root compression 1, 3. The mild spondylosis noted on imaging does not explain the severity of symptoms or the positive SI joint provocative testing.
Comprehensive Pain Management Program - Met
The injection is not being used in isolation but as part of a multimodal approach:
Ongoing pharmacotherapy with NSAIDs, neuropathic pain medication, and muscle relaxants 1, 2
Continuation of home exercise regimen post-injection 1
Plan includes consideration for medial branch blocks and potential radiofrequency ablation if diagnostic blocks are positive 2
Frequency and Number Limitations - Compliant
Timing: Last documented SI joint injection was 7/20/23 (>18 months ago), well exceeding the minimum 7-day interval requirement 4, 2
Annual limit: Plan appropriately limits to 4 injections per year, which aligns with policy 2
Procedural Safety and Expected Outcomes
Fluoroscopic guidance will be used, which is the preferred imaging modality ensuring accurate intra-articular needle placement and ruling out intravascular positioning 4, 7. The procedure carries minimal risk, with common side effects limited to injection site soreness (12.9%), pain exacerbations (5.3%), and vasovagal reactions (2.5%) 4. Serious complications such as infection are exceedingly rare 4.
Based on recent observational data, 60.6% of patients achieve minimal clinically important difference in pain scores at 1 month, 42.1% at 3 months, and 47.5% at 6 months following fluoroscopically guided intra-articular SI joint injection 6.
Critical Caveat Regarding the 70% Relief Criterion
The policy states that additional therapeutic injections require 70% reduction in pain after the previous injection. 1 The patient achieved only 50% relief from the 7/20/23 injection. However, this criterion appears to apply to determining if a patient should proceed beyond the initial 2 diagnostic/therapeutic injections to additional therapeutic injections within the same treatment series.
In this case, sufficient time has elapsed (>18 months) that this represents a new treatment episode rather than continuation of the previous series. 2 The patient demonstrated >50% relief for 3 months, which meets the Spine Intervention Society threshold for considering repeat injection 2. Additionally, the earlier 6/17/21 bilateral injections achieved 80% relief, demonstrating the patient is capable of robust response to this intervention 2.
Functional Improvement Documentation
The Pain Disability Index score improved from 39 (2/5/25) to 19 (3/11/25), representing a clinically significant reduction in disability that correlates with the therapeutic effect of the most recent injection 6.
Authorization should be granted for the planned left sacroiliac joint injection with fluoroscopic guidance using local anesthetic and corticosteroid. 4, 7