2007 ICD-9-CM Procedure 20.42 Radical mastoidectomy 20.42 is a specific code that can be used to specify a procedure 20.42 contains 3 index entries View the full Volume 3 20.* hierarchy Index entries containing 20.42: Mastoidectomy (cortical) (conservative) 20.49 radical 20.42 modified 20.49 Mastoidotympanectomy 20.42 Tympanomastoidectomy 20.42