Cervical Medial Branch Block Volume Dependent Dispersion Patterns as a Predictor for Ablation Success: A Cadaveric...

Area of Science:

• Pain Management
• Interventional Radiology
• Anatomy

Background:

• Neck pain is a leading cause of chronic pain and disability, often linked to facet arthropathy.
• Cervical radiofrequency ablation (RFA) is a treatment for refractory neck pain, guided by diagnostic cervical medial branch blocks (MBBs).
• Current MBB techniques have high false positive rates, potentially due to large injectate volumes (≥0.50 mL) reducing diagnostic specificity.

Purpose of the Study:

• To compare injectate dispersion between 0.25 mL and 0.50 mL volumes during cervical MBBs in a cadaveric model.
• To assess the impact of injectate volume on the spread and coverage of targeted nerves and adjacent structures.

Main Methods:

• A cadaveric study utilizing six human cervical spines.
• Bilateral cervical MBBs were performed using posterior approach under fluoroscopic guidance.
• 0.25 mL or 0.50 mL of contrast and dye solution was injected, followed by CT imaging and gross dissection to evaluate spread.

Main Results:

• Both 0.25 mL and 0.50 mL volumes adequately coated the targeted medial branches.
• The 0.50 mL volume showed dorsal spread to superficial muscles and distant nerves, indicating potential non-target coverage.
• The 0.25 mL volume remained localized within deep and intermediate muscular layers adjacent to the targeted nerves.

Conclusions:

• Injecting 0.50 mL in cervical MBBs may lead to non-specific nerve coverage, reducing diagnostic accuracy.
• 0.25 mL injectate volume effectively bathes the target medial branches with minimal extravasation.
• Using smaller volumes (0.25 mL) in cervical MBBs can increase specificity and potentially improve radiofrequency ablation planning for neck pain.