Exposing Brachial Plexus: A Surgical Technique to Visualize Brachial Plexus in Neonatal Piglet

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.

1. Animal Arrival and Acclimation

1. Quarantine 1–2 day-old piglets for at least 24 h after arrival.
2. House piglets in clean and sanitized stainless-steel cages (36 in x 48 in x 36 in) on aspen chip bedding and feed ad libitum with pig milk replacer.
3. Maintain the room temperature at 85 °F to ensure a thermo-neutral environment.

2. Day of Experiment

1. Remove the feed 2 h prior to the experiment.
2. Inject piglets with an intramuscular injection of ketamine (10–40 mg/kg)/xylazine (1.5–3.0 mg/kg IM) and transport via a transport cage to the surgical space.

3. Induction and Maintenance of Anesthesia

1. Administer 4% isoflurane inhalation anesthetic mixed in oxygen by nose cone and confirm that the animal is deeply anesthetized by assessing the absence of palpebral and withdrawal reflexes.
2. Intubate the animal by placing it in the supine position and use a laryngoscope (straight blade) to help guide the intubation tube (diameter 2.5–2 mm) into the trachea.
3. Place the animal on the ventilator once intubation tube is secured.
4. Ensure that piglets receive a mix of isoflurane (0.25%–3% maintenance), oxygen, and nitrous oxide.
5. Provide a dose of fentanyl (10 μg/kg) and continue giving a dose every 1–2 h to ensure continued adequate depth of analgesia and sedation and to avoid motion artifacts that could risk dislodgment of the endotracheal tube.
6. Establish intravenous (IV) access in the subcutaneous abdominal vein or any other peripheral vein.
7. Establish the arterial line through the femoral artery. This can be done non-invasively or by performing a cut-down.

4. Brachial Plexus Surgery

1. Place the animal in a supine position on the operating table after proper anesthesia as described in section 3, with the upper limb in abduction, exposing the axillary region.
2. Use any surgical drape to cover the animal. Use clean but non-sterile techniques.
3. Expose the brachial plexus complex on both sides of the spine by making a midline incision (using a #10 blade) over the skin and fascia overlying the trachea, down to the upper third of the sternum, corresponding to spine levels between C3–T3.
4. Extrapolate the incision using the forceps and hemostat horizontally on each side from the suprasternal notch along the edge of the clavicle to the upper arm, while sparing the cephalic and basilic veins.
5. Release the superior and inferior flaps by blunt dissection using scissors and forceps, allowing access to the cervical and thoracic regions of the brachial plexus, respectively.
6. Identify the axis (C2) and first rib at the T1. Using these landmarks, identify the lower three cervicals (C6–C8) and first thoracic (T1) spinal vertebral foramen, then examine the plexus carefully to locate bifurcations of the divisions (M shape) to achieve exposure.
7. Label (using nerve loops) the brachial plexus regions above these bifurcations closer to the spine as root/trunk and label those below these bifurcations as chords followed by the nerve, which are located closer to the arm.