Ultrasound-guided erector spinae plane block in horses: a cadaver study

Area of Science:

• Veterinary Anatomy
• Regional Anesthesia
• Equine Medicine

Background:

• The erector spinae plane (ESP) block is a regional anesthesia technique with potential applications in equine pain management.
• Understanding dye spread and nerve involvement is crucial for assessing efficacy and safety.

Purpose of the Study:

• To delineate dye distribution and spinal nerve contact following a simulated ESP block in equine cadavers.
• To evaluate the potential of ESP blocks for desensitizing thoracic spinal nerves in horses.

Main Methods:

• An experimental cadaver study involving 10 adult equine cadavers.
• Ultrasound-guided injection of a lidocaine/dye solution into the ESP at the Th16 level.
• Dissection and magnetic resonance imaging to assess dye spread, nerve staining, and epidural migration.

Main Results:

• Dye stained the thoracolumbar fascia in 85% of injections, with intramuscular placement in 15%.
• Multisegmental dorsal rami staining occurred in all evaluated specimens; ventral rami staining was observed in 3/14.
• Epidural spread was noted in 20% of injections, with no dye found in thoracic/abdominal cavities or on the sympathetic chain.

Conclusions:

• The ESP block demonstrates potential for targeting dorsal thoracic spinal nerves in horses.
• Further investigation is warranted to address the risk of epidural contamination and associated complications.