Abstract Objective: To compare the incidence and the histopathological aspect of spontaneous and two induced Mongolian gerbils’ models of cholesteatoma: External Auditory Canal (EAC) obliteration model and the Auditory Tube (AT) cauterization model. Methods: Fifty-four ears of 27 animals were divided into EAC obliteration, AT cauterization, and control groups and histologically assessed for cholesteatoma incidence and classification at intervals of 2, 4, 8, and 16 weeks. Results: Cholesteatoma was diagnosed in 30 of the 53 ears evaluated with a significantly higher incidence in groups that received some type of intervention (p < 0.0001). It was not possible to histologically distinguish cholesteatomas of the same stage between the study groups. Conclusion: Although we observed a significant increase in cholesteatoma incidence with the two methods used when compared to the control group, all developed cholesteatomas were apparently identical from a histological point of view.

Abstract Introduction Cholesteatoma is a disease with significant clinical impact but is incompletely understood. The challenge of performing studies with long-term follow-up in humans is a factor that has restricted the advance of knowledge in this field. Thus, the use of animal models is highly pertinent, and the Mongolian gerbil model has emerged as one of the most useful. Objective The present study aims to evaluate, through serial otoendoscopies, the development and characteristics of pars flaccida retraction pocket and cholesteatoma in Mongolian gerbils after obliteration of the eustachian tube and compare it with the control group. Methods Forty Mongolian gerbils were divided into two groups of 20 animals each. In the intervention group, the animals were followed with serial otoendoscopies after eustachian tube obliteration. In the control group, the animals were only followed through serial otoendoscopies. Results At the end of the 16-week follow-up, cholesteatoma was present in 13 of 38 (34.2%) ears in the intervention group, and in 7 of 34 (20.6%) in the control group (p = 0.197). When we considered cholesteatoma and its potential precursor, pars flaccida retraction pocket, in a combined way, we verified it in 23 of 38 (60.8%) in the intervention group and in 11 of 34 (32.3%) in the control group (p = 0.016). Conclusions Over the 16 weeks of follow-up, serial otoendoscopies enabled us to evaluate the formation and development of pars flaccida retraction pockets and cholesteatomas in Mongolian gerbils and proved to be an excellent diagnostic tool.

Abstract Introduction The treatment of cholesteatoma is generally surgical, and the major obstacle is the high prevalence of recidivism. The endoscopic ear surgery technique is proposed to minimize this problem. Objectives To utilize endoscopes to visualize and manipulate cholesteatoma residues after microscopic removal Methods Cross-sectional study. Thirty-two patients with cholesteatoma underwent microscopic wall-up mastoidectomy combined with the endoscopic approach. The subjects were assessed for the presence and location of covert disease. Results Of the 32 cases, 17 (53.12%) had residual cholesteatoma in the endoscopic phase. Minimal disease was found, usually fragments of the cholesteatoma matrix. Pars tensa cholesteatomas had more covert disease than pars flaccida cholesteatomas (62.50% vs 43.75%). Posterior recesses (47.05%) and tegmen tympani (41.17%) were the locations with more covert disease (p< 0.05). Conclusion Cholesteatomas of the pars tensa presented more residual disease and were significantly more common in the posterior recesses and tegmen tympani.