Assessment of an Ultrasound-Guided Rectus Sheath Block in Foals: A Cadaveric Study.
Authors: Gutiérrez Bautista Álvaro Jesús, Söbbeler Franz Josef, Koch Rüdiger, Viscasillas Jaime, Kästner Sabine
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Ultrasound-Guided Rectus Sheath Block in Foals Umbilical pathology and surgical intervention represent significant sources of postoperative pain and complications in neonatal foals, necessitating effective regional analgesia techniques to improve outcomes. Researchers performed bilateral two-point ultrasound-guided rectus sheath blocks on ten foal cadavers using injections positioned 5 cm cranial and caudal to the umbilicus, administering 0.25 mL/kg at each site, then assessed dye distribution via computed tomography and surgical dissection. The contrast medium extended 0.8–1.4 cm per millilitre of injectate, with consistent staining of thoracic spinal nerves 16, 17, and 18 (at 95%, 85%, and 80% respectively), although abdominal cavity contamination occurred in four cadavers, suggesting the block may breach the peritoneum in some cases. For equine practitioners managing foals undergoing umbilical surgery, this technique offers a promising approach to periumbilical analgesia, though the anatomical variation evident in the cadaveric findings warrants cautious application and consideration of supplementary analgesia until efficacy is confirmed in living animals. Further investigation with varying injectate volumes and clinical validation is essential before widespread adoption into regional anaesthesia protocols.
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Practical Takeaways
- •This cadaveric study validates a practical ultrasound-guided nerve block technique that could reduce pain during umbilical surgery in foals, a common neonatal procedure
- •The bilateral two-point injection approach (5 cm cranial and caudal to umbilicus) consistently blocks the relevant nerves supplying the surgical area
- •Future clinical trials with living animals and optimized injectate volumes are needed before routine adoption in practice; the 40% risk of abdominal contamination warrants investigation
Key Findings
- •Two-point ultrasound-guided rectus sheath block at umbilicus level achieved cranio-caudal contrast extension of 0.8–1.4 cm per mL of injectate
- •Thoracic nerves 16, 17, and 18 were most consistently stained (95%, 85%, and 80% respectively)
- •Abdominal cavity contamination occurred in 4 of 10 cadavers (40%)
- •Block technique shows promise for periumbilical analgesia in foals undergoing umbilical surgery