الملخص

objective: To study the causes of failure (canal wall down) mastoidectomy procedure.Design: A prospective case series study.Setting: ENT department, Al-Jamhory teaching Hospital during the period of May 1996 to May 2000.Participation: Twenty five patients underwent canal wall down operation over a period of four years. They were reviewed for the final result after the operation.Results: Fifteen patients were noticed to have complete dryness and healing. Eighty percent of the patients get dry ear within the first three months after the operation. failure to get healed cavity was seen in patients with large cavities, high facial ridge and inadequate meatoplasty.conclusion: Recognition -of the possible causes of failure to get dry ear, the surgeon's experience and the regular follow up of the patient, may help in achieving better results.