My 6yo is having a mastoidectomy, can anyone tell me what to expect?

Consult w/ your ENT: There are different types of mastoidectomy procedures depending on your situation; some types may result in a degree of hearing loss. Complications are less common; healing depends on the type of performed, your level of infection, and your physiology (how well you heal/recover). Alternatives include medication or delay of treatment. I recommend a thorough discussion with your surgeon & referring doctor.