Tracer Molecule Delivery in the Cisterna Magna: A Method to Deliver Fluorescent Tracer Molecules via Direct Cannulation of the Cisterna Magna in Pig

Ensure that one person elevates and flexes the head and neck of the animal, while the other palpates for the cisterna magna, making a note of its anatomical location. Introduce a 22-gauge cannula slowly and carefully into the cisterna magna through the dura, at an angle oblique to the longitudinal axis. Then, retract the needle from the cannula and place a cap on the lock.

Start with applying superglue and an accelerator where the cannula enters the tissue. Then, apply the dental cement. Wait five minutes for the cement to harden. Remove the cap carefully from the cannula. Attach the cannula to the male end of the IV line tap with the tracer using a 10-centimeter extension.

Inject the tracer slowly at a rate of 100 microliters per minute either by hand or using a micro-infusion pump. Remove the IV line tap and replace it with the cap. Check if the tracer is visible, pulsating at the base of the cannula. Then, place sandbags under the neck of the animal to maintain some flexion.

Release the head, and leave the animal in a resting, prone position. Release the self-retaining retractors and replace the muscles. Use the surgical towel clamps to bring the skin together over the muscles. First use gauze, and then, a blanket to cover the towel clamps and the incision to limit heat loss. Allow the tracer to circulate for the desired amount of time.