Open and closed cavity mastoid operations: comparing early hearing results

The aim of the study is to compare audiological results in patients treated surgically with either an open or closed cavity mastoidectomy. A prospective review of a single surgeon’s case series based at two district general hospitals. All patients with 1-year post-operative hearing results following an open or closed cavity mastoid surgery were included. Outcome measured included the preoperative and postoperative air-bone gap (ABG). Belfast rule of thumb was used to assess the benefit from middle ear surgery. A total of 128 patients were identified from the database with 1 year post-operative hearing results. Sixty-three patients had undergone an open cavity mastoidectomy and 65 had a closed cavity mastoidectomy. The mean post-operative ABG in patients with open cavity mastoidectomy was 24 dB and for closed cavity 21 dB (p = 0.12). There was no statistical difference between open and closed cavity mastoidectomy with or without ossiculoplasty and if the underlying pathology was squamous or mucosal disease. However, patient with post-operative ABG below or equal to 20 dB was 41% for closed cavity compared to 21% for open cavity. Using the Belfast rule of thumb, 79% of the patients in both groups had successful hearing results post surgery. The 1-year post-operative audiological results between open and closed cavity masoidectomy showed no statistical difference. The pathology affecting the middle ear also had no influence on the hearing results between the two groups. However, there was a higher percentage of patients with closed cavity procedures who had a post-operative ABG that was below or equal to 20 dB.