Canalostomy for Local Drug Delivery into the Inner Ear of an Adult Mouse

Begin with an anesthetized mouse placed in a right lateral position.

Make an incision behind the ear and dissect the underlying muscles to expose the semicircular canals.

Excise a small muscle piece for later use.

Locate the posterior semicircular canal or PSC, a fluid-filled duct within the inner ear.

Make a hole in the middle of the PSC and clean the area.

Take a cannula connected to a drug-filled micro-syringe, which is attached to a syringe pump.

Insert this cannula into the hole on the PSC and move it towards the crus commune, a region where the posterior canal merges with the anterior canal, to access the inner ear.

Inject the drug solution through the cannula into the inner ear, ensuring local drug delivery.

Post-delivery, remove the cannula and place the excised muscle piece into the hole to prevent leakage. Finally, close the incision with sutures.

Begin by placing the anesthetized mouse on a pre-heated electric pad. Set the temperature of the electric pad to approximately 37 degrees Celsius. Cover the animal's eyes with eye ointment, then shave the left postauricular region with an electric animal clipper, and disinfect the skin three times with 75% ethanol.

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