<prompt> What is the COMMONEST complication of CSOM?Subperiosteal abscessMastoiditisBrain abscessMeningitis  <response>: Mastoiditis is the most common complication of CSOM. Acute mastoiditis usually accompanies or follows acute suppurative otitis media. Complications of otitis media are classified into two main groups: A.Intratemporal: Mastoiditis Petrositis Facial paralysis Labyrinthitis B.Intracranial: Extradural abscess Subdural abscess Meningitis Brain abscess Lateral sinus thrombophlebitis 