Ultrasound-guided interfascial rectus sheath-associated plane block in sheep: a cadaveric study

Area of Science:

• Veterinary Anatomy
• Regional Anesthesia
• Surgical Techniques

Background:

• The rectus sheath block (RSB) is a valuable regional anesthesia technique in human medicine.
• Its feasibility and efficacy in ovine species require investigation due to anatomical differences.

Purpose of the Study:

• To assess the anatomical feasibility of an ultrasound-guided interfascial rectus sheath (RS)-associated plane block in sheep cadavers.
• To evaluate dye distribution and nerve staining following the block.

Main Methods:

• A prospective, experimental, randomized cadaveric study involving 22 ovine cadavers.
• Anatomical and ultrasonographic examinations were performed, followed by ultrasound-guided injections of methylene blue into the rectus abdominis muscle (RAM) and its internal sheath plane.
• Dye distribution and nerve staining were assessed via dissection.

Main Results:

• The one-injection approach demonstrated consistent staining of the eleventh thoracic nerve.
• Limited dye spread was observed, indicating compartmentalization within the interfascial plane.
• Staining of the twelfth and thirteenth thoracic nerves was inconsistent.

Conclusions:

• The evaluated ultrasound-guided rectus sheath block technique in sheep cadavers resulted in limited spread and nerve staining, likely due to species-specific anatomy.
• Targeting individual muscular compartments may offer an alternative approach.
• Further research using the traditional RSB technique is recommended to confirm its applicability in sheep.