Preprocedural Radiographic Measurements Facilitate Centesis of the Equine Navicular Bursa.

Overview

• This study evaluates the use of radiographic measurements to improve the accuracy of needle placement for centesis (fluid aspiration) of the equine navicular bursa, which is a small fluid-filled sac in a horse’s hoof.
• The research found that using specific radiographic landmarks helped novice veterinary students achieve a high success rate in needle placement, suggesting this method could be a valuable aid in clinical settings.

Background and Purpose

• The equine navicular bursa is a structure located near the navicular bone in a horse’s hoof, and centesis is a procedure used to inject medication or withdraw fluid from it.
• Correct needle placement is essential and typically confirmed using radiographs (X-rays), but this can be difficult logistically during the procedure.
• The study aimed to determine whether preprocedural radiographic measurements could guide needle placement without relying heavily on live radiographic confirmation.

Methodology

• Researchers used 26 isolated equine limbs and took lateromedial radiographs to identify and measure the center of the flexor surface of the navicular bone—a key anatomical landmark for injection.
• Based on these measurements, 21 veterinary students with limited experience each performed multiple needle placements (totaling 130 attempts) using an axial distal palmar approach.
• Each needle placement involved injecting one of five different colored dyes into the cadaver limbs to simulate the procedure.
• After injections, dissections were performed to assess the success of needle placement by checking for the presence of dye on the bursal surface and within the deep digital flexor tendon.

Key Findings

• The overall success rate was high at 84.6%, indicating that the students were able to accurately place the needles most of the time using only the radiographic measurements as guidance.
• There were significant differences in success related to the dye color used, with pink and brown dyes being less often found in the correct location—suggesting either dye-related procedural factors or visibility issues during dissection.
• No significant differences in success were observed between different limbs, indicating consistent applicability of the measurement technique.

Implications

• The study supports the potential use of precise radiographic measurements taken before the procedure to facilitate accurate needle placement during navicular bursa centesis.
• If future in vivo (live horse) validation confirms these findings, this technique could reduce the need for real-time radiographic confirmation, simplifying the procedure.
• This could be particularly helpful in clinical settings where immediate radiographic confirmation is impractical or unavailable, enhancing the efficiency of treatment delivery in equine medicine.

Limitations and Future Directions

• The study was conducted on isolated limbs, not live animals, so tissue response and movement factors in living horses were not assessed.
• Variability in dye visibility suggests that technique refinement and standardization may be needed to ensure consistency in practical use.
• Further research is required to validate these radiographic measurement techniques in live horses and to assess the clinical outcomes following their use.