A 10-year review of malignant otitis externa: a new insight

OBJECTIVES: This study aims to assess the clinical trends of malignant otitis externa (MOE) and classify MOE based on the findings related to high-resolution computed tomography (HRCT) of the temporal bone and 99-Tech3-Phase Bone Scintigraphy (TPBS). We also reconstruct a treatment algorithm for MOE in our institution.

METHODOLOGY: A 10-year retrospective review was carried out on MOE in a single otology institution from January 2011 to December 2020. The MOE was classified based on proposed Tengku's radiological stratification according to HRCT and TBPS findings. Phase I is defined as inflammation limited to the soft tissue in the external auditory canal, without involvement of the bone. Phase II is the inflammation beyond the soft tissue, involving bone, but limited to the mastoid. Phase III is when the inflammation extends medially, involving the petrous temporal bone or temporomandibular joint, with or without parapharyngeal soft tissue involvement. Phase IV refers to inflammation extending medially to involve the nasopharynx, with or without abscess formation. Finally, Phase V is inflammation that further extends to the contralateral base of the skull.

RESULTS: A sample of 49 patients was involved in this study. Majority of the patients were having Phase III (36.7%) of the disease, followed by Phase V (24.5%), Phase II (18.4%), Phase IV (16.3%), and Phase I (4.1%). A comprehensive treatment algorithm was drafted based on our institution's experience in managing MOE. The mortality rate was low (8.2%), mainly involving patients in advanced phase of the disease (Phases IV and V).

CONCLUSION: This study has revealed the evidence of progression of MOE based on the proposed radiological stratification. This stratification is simple and practically applicable in clinical settings. We suggest the use of our proposed treatment algorithm as a standard diagnostic and treatment protocol for MOE.