Taking Ear Impressions with Large Mastoid Cavities

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Answer

I've done about half a dozen of these. A lot depends on the size and shape of the cavity. Take extra time with otoscopy, particularly at the margin of the surgical area, so you'll know precisely how to pack it. If this is the kind of cavity where you can see everything with a flashlight as well as you can with an otoscope, you might do better with cotton packing material rather than otoblocks. No strings needed in this case and you can pick the cotton out with alligator forceps.

If this is not the kind of cavity where you can see everything, your otoblock material must have strings. The surgical area may delve in any direction. I recommend filling the surgical area with otoblock material. The block should extend all the way to the margin of the normal EAC section and maybe a little into the normal section. That will give you a better opportunity to make a mold of the proper depth with much less chance of blow-by.

If you try to keep the otoblock in a normal section of the EAC that's distal to the surgical area and the surgical area balloons closer to the TM, it's likely you'll push the block into the surgical area when you start laying impression material. It's also possible your impression will be shorter than you want if you manage to keep from pushing the block. Make sure you have enough impression material prepared. A surgical ear may take more than normal.

Don't worry about the impact of multiple strings because the ear mold company can fill in. The ear mold company is likely to recognize a mold from a surgical ear but it's best to tell them. Think carefully about style and material. If this is an experienced user they'll have a preference. A surgical ear is often more sensitive than normal. If it's a new user I'd probably pick acrylic for ease of insertion.

David Taylor, M.A., is an audiologist and the owner of Ears to You in Newport News, VA. He is a graduate of San Diego State University and has been practicing audiology for over 12 years.