Ultrasound-Guided Dorsolateral Approach for Quadratus Lumborum Block in Rabbits (Oryctolagus cuniculus): A...

Area of Science:

• Veterinary Anesthesiology
• Comparative Anatomy
• Regional Anesthesia Techniques

Background:

• Ultrasound-guided (US-guided) loco-regional anesthesia offers analgesia and anesthetic-sparing benefits in rabbits.
• The quadratus lumborum (QL) muscle's anatomy in rabbits is crucial for developing targeted blocks.

Purpose of the Study:

• To investigate rabbit thoraco-lumbar anatomy, focusing on the QL muscle.
• To design a rabbit-specific US-guided QLB.
• To determine the optimal injectate volume for effective nerve coverage without adverse effects on pelvic limb innervation.

Main Methods:

• Sixteen adult rabbit cadavers were used.
• US-guided QLB was performed with varying injectate volumes (0.1-0.4 mL/kg) and injection sites (right/left QL fascia).
• Injectate consisted of lidocaine, iodinated contrast, and tissue dye; spread was evaluated using CT and dissection.

Main Results:

• A dorsolateral approach using 0.3 mL/kg of injectate was adequate in most cases.
• 0.4 mL/kg consistently covered target nerves (T11-L3) but also affected L4 and beyond.
• 0.3 mL/kg appears optimal for targeted analgesia without compromising pelvic limb function.

Conclusions:

• A rabbit-specific US-guided QLB is feasible.
• An injectate volume of 0.3 mL/kg is recommended for effective analgesia of the thoraco-lumbar region.
• This technique offers a precise approach to loco-regional anesthesia in rabbits.