Accuracy of ultrasound-guided injections of thoracolumbar articular process joints in horses: a cadaveric study.
Authors: Fuglbjerg V, Nielsen J V, Thomsen P D, Berg L C
Journal: Equine veterinary journal
Summary
# Editorial Summary: Ultrasound-Guided Injections of Thoracolumbar Articular Process Joints Arthrosis affecting the articular process joints (APJs) in the caudal thoracolumbar spine is a recognised cause of back pain, poor performance and lameness in horses, yet ultrasound-guided injection techniques for these structures remain poorly characterised in the literature. Fuglbjerg and colleagues performed 154 blue-dye injections targeting APJs from T14 to L6 in 12 cadaver horses, then dissected the spines to determine whether deposits were intra-articular or within 2 mm of the joint capsule. Only 27% of injections achieved true intra-articular placement; however, 77% overall were either within or very close (≤2 mm) to the joint capsule, with the medial approach and 18-gauge needles significantly improving accuracy, whilst operator experience and specific joint location did not materially affect outcomes. These findings suggest ultrasound-guided APJ injection is a technically viable procedure in principle, though the relatively modest intra-articular success rate warrants careful consideration of technique refinement—particularly adoption of the medial approach—before clinical application in live horses; further investigation is essential to establish whether the 77% near-capsule deposition rate translates to meaningful diagnostic or therapeutic benefit in practice.
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Practical Takeaways
- •Use a medial approach with 18 gauge needles when performing ultrasound-guided APJ injections in horses with thoracolumbar pain or arthrosis
- •Accept that even with ultrasound guidance, achieving true intra-articular placement is challenging in cadavers; clinical outcomes should be monitored closely in live horses
- •This technique may offer diagnostic and therapeutic value for horses with suspected articular process joint disease, but requires further clinical validation
Key Findings
- •Only 27% of ultrasound-guided injections were intra-articular, but 77% were within 2 mm of the joint capsule
- •Medial approach and 18 gauge needles were significantly associated with accurate intra-articular placement or close capsular deposition
- •Operator experience and specific joint location did not significantly affect injection accuracy
- •Ultrasound guidance proved reliable for targeting articular process joints in the thoracolumbar region