Chronic suppurative otitis media (CSOM) is characterized by intermittent or continuous otorrhea lasting for longer than 6 weeks. Most cases can be treated conservatively using antibiotic drops and oral antibiotics. However, some cases will not respond to conservative treatment and demonstrate persistant discharge. In these cases, especially if a CT-scan shows opacification of the mastoid air cells, a mastoidectomy can be considered as treatment modality. In recent years, obliteration of the mastoid cavity following mastoidectomy is gaining popularity. However, the effectiveness of obliterating the mastoid in comparison to mastoidectomy alone is uncertain for CSOM. In this retrospective cohort study, our aim is to compare mastoidectomy to mastoidectomy + mastoid obliteration in a cohort of patients suffering from CSOM with mastoid involvement. The hypothesis is that obliterating the mastoid cavity will result in a higher frequency of dry ears and in a lower frequency of revision surgeries.

Inclusion Criteria:

• Suffering from CSOM, as indicated by otorrhea as main complaint preoperatively
• At least one year of follow-up, in order to asses the primary outcome
• Opacification of the mastoid air cells on preoperative CT-scans, as indication for mastoid involvement
• Canal wall up or canal wall down mastoidectomy
• Operated between 2010 and 2022

Exclusion Criteria:

• Patients suffering from middle ear cholesteatoma

All patients that underwent canal wall up or canal wall down mastoidectomy between 2010 and 2022 will be evaluated. Only cases that full-fill the in- and exclusion criteria will be selected. Patients will be stratified for whether they received mastoid obliteration or not.