I had to look it up,
Ear canal ablation and bulla osteotomy
•Dogs that have had long-standing ear infections may develop irreversible damage to the ear canal. Due to chronic inflammation, the ear canal becomes very thickened and can turn into bone. As a result, the infection will not resolve with medication. The middle ear cavity (tympanic bulla) frequently is infected as the ear drum is commonly ruptured with chronic ear infections.
•Cancer of the ear canal is another disease requiring this type of surgery. In dogs, surgery is usually curative for malignant cancer (adenocarcinoma) of the ear canal, if the tumor has not invaded through the cartilage or into the middle ear cavity. If your pet has an ear tumor, chest radiographs (x-rays) will be taken to help rule out the possibility of spread of the cancer to the lungs.
•Congenital imperforate ear canal resulting in middle ear infection.
In other words, people who put off going to the vet with those pesky ear infections and home treat can cause this.
This site describes the procedure and says,
"In most cases, the results are nearly miraculous. Patients demonstrate more energy now that their headaches are gone. There is no more odor, ear cleaning, or pain."
Total Ear Canal Ablation and Ventral Bulla Osteotomy: The TECA Procedure - VeterinaryPartner.com - a VIN company!