Cannula Implantation into the Cisterna Magna in a Mouse Model

Begin with an anesthetized mouse placed in a stereotaxic frame, its head tilted downward to allow easier access to the cisterna magna, a space filled with cerebrospinal fluid or CSF.

A midline scalp incision exposes the cisterna magna, which appears as an inverted triangle between the cerebellum and medulla, covered by the dural membrane.

Use a cotton swab to clean excess fluid from the dura.

Using tweezers, grasp a cannula near the needle portion.

Insert the needle at an angle through the dura into the cisterna magna’s center, avoiding penetration in the cerebellum and medulla.

Clean any leaked CSF.

Apply adhesive to the dura to secure the cannula, then add a glue accelerator for immediate adhesion.

Cover the incision with a mixture of cement and adhesive, followed by a glue accelerator.

The intracisternal cannulated mouse is ready for targeted CSF delivery of therapeutic agents.

Fix the mouse in the stereotaxic frame, making use of either the intraneural arch or the zygomatic arch. Then, tilt the head slightly so that it forms an angle of 120 degrees to the body.

Next, apply ophthalmic ointment and reapply it as needed during the surgery. Find the occipital crest, which is the part of the skull protruding immediately above the neck muscles. Lift the overlying skin using a pair of tweezers and cut an almond-shaped piece of skin of approximately one centimeter along the midline.

Then, using the occipital crest as a reference point, pull apart the superficial connective tissue to expose the neck muscles below. Use cotton swabs or eye spears to control any resultant bleeding. To proceed, separate the muscles at the midline by carefully running the tweezers down the middle of the incision site in the anterior to posterior axis.

Then, with a pair of curved forceps in each hand, join the tips in the middle near the bottom of the skull and pull the muscles aside to expose the cisterna magna. The cisterna magna looks like a tiny inverted triangle, outlined by the cerebellum above and medulla below. Using a surgical eye spear or cotton swab, wipe the dural membrane covering the CM.Next, with curved tweezers in the dominant hand, grasp the cannula near the tube-covered needle.

Then, place the middle finger of the other hand on the ear bar to create a stable rest for the cannula. Now, at the center of the CM, puncture the dura at 45 degrees relative to the mouse head. Only insert the needle to where the bevel is under the dura to avoid penetrating into the cerebellum or medulla.

If necessary, clean off any leaked CSF with a spear or swab. Then, apply a few drops of cyanoacrylate onto the dural membrane surrounding the cannula and add a drop of glue accelerator to cure the glue immediately. Next, combine dental cement and cyanoacrylate glue.

Then, cover the entire incision site and quickly apply a drop of glue accelerator to cure.