Protocol for canalostomy in rats to enable inner ear injection

Here, we present a protocol for precise inner ear access in rats using a refined canalostomy technique. We describe steps for surgical exposure of the mastoid bone, localization of the target semicircular canal, fenestration using a cranial drill, and quantitative microinjection of agents. We further validate this approach by presenting fluorescence-based assessment results. This standardized approach enables reproducible delivery of chemicals or viruses into the inner ear.