Is a sacroiliac joint (SIJ) injection with image guidance (fluoroscopy or computed tomography (CT)) considered medically necessary for a patient with lower back pain who had a previous SIJ injection with no documented significant pain relief?

Medical Necessity Determination for Repeat SIJ Injection

The requested sacroiliac joint injection is NOT medically necessary based on the available documentation, as there is no evidence of at least 70% pain relief from the previous injection, which is the threshold required by established guidelines for repeat therapeutic injections. 1, 2

Critical Missing Documentation

The case lacks the essential outcome data from the previous bilateral SIJ injection performed on the earlier date. The clinical notes explicitly state:

• Post-injection assessment documented 0% pain relief - The patient reported "0 pain relief currently" approximately 1.5 hours after bilateral SI joint injections [@Case Summary@]
• The plan's medical necessity criteria requires at least 70% reduction in pain from the previous injection to justify additional therapeutic injections [@CPB 0016@]
• Without documented significant relief from the prior injection, the criteria for repeat injection are not met 1, 2

Evidence-Based Threshold Requirements

The Spine Intervention Society's appropriate use criteria specify that repeat injection with steroid is appropriate only if:

• There was ≥75% relief from a diagnostic local anesthetic SIJ injection, OR
• There was at least 50% relief for at least 2 months after the first injection to suggest therapeutic benefit from steroid effect 1, 2

The American College of Physical Medicine and Rehabilitation recommends:

• Patients must demonstrate at least 70-80% pain relief from diagnostic SI joint injections to confirm the SI joint as the primary pain generator before proceeding with additional interventions 2, 3
• This threshold provides diagnostic specificity of 78% for identifying the SI joint as the true pain source 2

Analysis of This Case

The documented injection history reveals a concerning pattern:

• The patient has received multiple interventions including L3-4 lumbar epidural steroid injections and bilateral SI joint injections [@Case Summary@]
• The L3-4 interlaminar epidural "did not provide significant relief" [@Case Summary@]
• The most recent bilateral SI joint injections provided 0% pain relief at 1.5 hours post-procedure [@Case Summary@]
• The false-positive rate for diagnostic SI joint injections ranges from 11-63%, making stringent response criteria essential 3

Alternative Pain Generators

Given the lack of response to SI joint injections, other sources of lower back pain must be thoroughly evaluated:

• Lumbar disc pathology (particularly given the L3-4 epidural injection history) 4, 3
• Lumbar facet joint disease 4, 3
• Lumbar spinal stenosis 3
• Lumbar spondylolisthesis 3

Common Pitfall in This Case

The assumption that a "huge gap between two injections" implies the previous injection provided pain relief is not supported by clinical documentation. [@Case Summary@] The gap between injections could represent:

• Patient delay in seeking care
• Trial of other conservative treatments
• Referral delays
• Insurance authorization processes

Without documented objective pain relief measurements (numeric rating scale scores pre- and post-injection), medical necessity cannot be established. 1, 2

Required Documentation Before Approval

To meet medical necessity criteria, the following must be documented:

• Pre-injection pain score using numeric rating scale (NRS) 1
• Post-injection pain score at appropriate intervals (typically 30 minutes to 2 hours for anesthetic effect, and 2 weeks to 3 months for steroid effect) 1
• Calculation showing ≥70% reduction in NRS score from the previous injection [@CPB 0016@, 2]
• Duration of pain relief from the previous injection (should be at least 2 months if claiming 50% relief threshold) 1, 2

Recommendation

Deny the requested SIJ injection as not medically necessary. The available clinical documentation demonstrates 0% pain relief from the most recent bilateral SI joint injections, which falls far below the required 70% threshold for repeat therapeutic injections. [1,2, @CPB 0016@]

Contact the provider to:

• Obtain complete documentation of pain relief outcomes from all previous SI joint injections
• Request objective pain scores (NRS) before and after previous injections
• Clarify the duration of any pain relief experienced
• Discuss evaluation for alternative pain generators given the poor response to SI joint interventions 4, 3