Essential surgeries for the electrophysiological recording from a behaving non-human primate brain 2 (Craniotomy)
Robert S Turner, Witold J Lipski, Daisuke Kase, Devin R Harsch
Abstract
Outlined below are the steps to complete a craniotomy in an existing recording chamber placed on a cranial implant. This procedure can be done concurrently with the implant surgery (not recommended), or can take place upon recovery from the implant surgery.
Steps
Preparation in the prep room on the day of surgery
Sedate the animal.
Intubate the animal, start the gas anesthesia, and bring it to the surgical suite.
Procedure in the surgical suite
Secure the animal’s head on the stereotaxic frame.
Open the recording chamber.
Clean the surface of the implants (chamber, head fixation post, dental acrylic, etc.) with Betadine and ethanol.
Scrub in for the surgery. Wash hands (5 min per hand) and don a surgical gown and sterile gloves.
Cover the animal’s whole body with a sterile drape.
Put a sterile drill bit in the pin vise, and expose the drill bit about 3-4 mm from the pin vise.
Slowly drill the first hole in the chamber with a pin vise until the pin vice touches the skull. The drill should not pierce the skull if the length is appropriately adjusted.
Extend the drill bit a small amount, approximately 0.5 mm, then return to the hole that you drilled.
Deepen the hole.
Move to the next step if the skull is pierced and you can see the surface of the dura (it will look like a fascia of a piece of chicken). If the skull has not been pierced yet, return to Step 10.
Make many holes to draw a circle of holes in the recording chamber.
Remove the bone between holes with the bone rongeur.
If bones between all holes are entirely removed, there should be a circle-shaped bone in the middle of the recording chamber.
Raise the circle-shaped bone with tweezers and/or excavator spoon slowly and carefully.
Remove the circle-shaped bone with tweezers carefully.
Expand the hole with the bone punches.
Scrape the sharp edge of the skull with the excavator spoon.
Rinse the small pieces of bone from the chamber with saline.
Measure the distance from the top edge of the chamber to the surface of the dura in multiple locations inside the chamber (ex. most medial, lateral, anterior, posterior corners, and center of the chamber).
Place the chamber's cap onto the chamber and secure it.
Stop the gas anesthesia, remove the intubation when the animal starts showing the reflex
Then, return the animal to the home cage.
