What are the recommended fluoroscopic on-time benchmarks for lumbar facet and intra-disc injections?

Fluoroscopic On-Time Benchmarks for Lumbar Facet and Intra-Disc Injections

The recommended fluoroscopic on-time benchmark for lumbar facet injections is approximately 37 seconds, while CT fluoroscopy-guided procedures should aim for under 5 seconds of actual fluoroscopy time to minimize radiation exposure. 1, 2

Radiation Exposure Considerations for Lumbar Injections

Fluoroscopy vs CT Guidance

• Conventional fluoroscopy-guided lumbar facet injections:

  • Mean fluoroscopy time: 37 seconds 1
  • Effective dose: 0.85 mSv for conventional fluoroscopy 1
  • For facet joint injections specifically: 0.10 mSv ± 0.11 2

• CT fluoroscopy-guided procedures:

  • Mean procedural fluoroscopy time: 4.7 seconds 1
  • Effective dose from fluoroscopy component: 0.45 mSv 1
  • Total effective dose including planning CT: 3.35 mSv 1
  • For facet joint injections specifically: 0.33 mSv ± 0.13 2

Radiation Exposure Comparison

The radiation dose from CT fluoroscopy itself is lower than conventional fluoroscopy due to shorter fluoroscopy times. However, the overall radiation dose for CT-guided injections is typically higher when including the preliminary planning CT scan, which contributes the majority of radiation exposure (2.90 mSv) 1.

Technique-Specific Considerations

Lumbar Facet Injections

• Intra-articular injections require less fluoroscopic time than periarticular injections (geometric mean: 39 vs 52 seconds) 3
• Both intra-articular and periarticular fluoroscopically guided facet injections provide similar pain relief outcomes 3
• Fluoroscopic guidance is essential for accurate needle placement, with studies showing that clinically significant pain reduction can be maintained for up to 3 months 4

Radiation Exposure to Practitioners

• Interventionalist radiation exposure is higher during fluoroscopy-guided compared to CT-guided procedures:
  • For lumbar transforaminal injections: 0.42 × 10⁻³ mSv vs 0.11 × 10⁻³ mSv (body dosimeter) 2
  • For wrist exposure: 1.44 × 10⁻³ mSv vs 0.14 × 10⁻³ mSv 2

Clinical Efficacy Considerations

Despite differences in radiation exposure, clinical outcomes do not differ significantly between fluoroscopy-guided and CT-guided injections 2. This suggests that the choice of imaging modality should primarily consider radiation exposure minimization while maintaining adequate visualization for accurate needle placement.

Recommendations for Minimizing Radiation Exposure

1. For conventional fluoroscopy:

   • Target fluoroscopy time under 40 seconds for facet injections
   • Use pulsed fluoroscopy rather than continuous mode
   • Limit the number of spot images taken

2. For CT fluoroscopy:

   • Limit actual CT fluoroscopy time to under 5 seconds
   • Minimize the dose from the preliminary planning CT scan by:
     • Reducing the z-axis coverage to only the necessary levels
     • Using low-dose protocols

Common Pitfalls and How to Avoid Them

1. Excessive radiation exposure: Use intermittent rather than continuous fluoroscopy and limit the number of spot images.

2. Unnecessary planning CT scans: When using CT fluoroscopy, consider whether a full diagnostic lumbar CT scan is truly necessary or if a limited scan would suffice.

3. Inaccurate needle placement: While minimizing fluoroscopy time is important, accuracy should not be compromised. Use appropriate imaging to confirm needle position before injection.

4. Failure to document fluoroscopy time: Consistently record and monitor fluoroscopy times to ensure adherence to benchmarks and identify opportunities for improvement.

By adhering to these fluoroscopic on-time benchmarks and implementing radiation reduction strategies, practitioners can minimize radiation exposure while maintaining the clinical efficacy of lumbar facet and intra-disc injections.