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Objectives To observe the benefit of endoscopic surgery for the treatment of lacrimal duct obstruction in revisional surgeries after external dacryocystorhinostomy. Study Design and Setting Retrospective nonrandomized study. Eleven cases of recurrent lacrimal duct obstruction after external dacryocystorhinostomy were submitted to endoscopic dacryocystorhinostomy. Results The rate of success after revisional surgery was 90.9%. The major causes of failure of the external approach were the presence of granulation tissue, septal deviations and synechiae near the opening of the fistula, inadequate removal of the bony wall adjuvant the lacrimal sac, technical error in the localization of the lacrimal sac, and excessive perioperative bleeding that impaired the surgical field. Conclusion Endoscopic dacryocystorhinostomy in revisional cases proved to be a safe technique of low morbidity, permitting effective resolution of the lacrimal obstructions. Significance Endoscopic surgery allows greater visibility of the lacrimal sac and its neighbor anatomic alterations and leads to better results.

Auditory conditioning consists of the pre-exposure to low levels of a potential harmful agent to protect against a subsequent harmful presentation. The agent that was first tested was noise. This paradigm was more recently successfully tested with other agents. Nonetheless, the vast majority of the studies utilize the same agent to condition and to cause the trauma. The aim of this study was to verify whether conditioning with an agent different from the agent used to cause the trauma can also be effective. Thus, the following groups were organized: group Cont, which is the noise trauma control group, was exposed to 110-dB broadband noise centered at 4 kHz for 72 h; group Gent, which is the gentamicin conditioning control group, was administered 30 mg/kg of gentamicin daily for 30 consecutive days; and group Expt was conditioned with gentamicin similarly to group Gent and then subjected to a noise trauma similarly to group Cont. The animals were functionally and morphologically evaluated through the measurement of the auditory brainstem response and scanning electron microscopy, respectively. The following variables were investigated: outer hair cell injury and auditory threshold shift. The group that was conditioned with the drug exhibited significantly less outer hair cell damage, 10.8 and 22.9 %, respectively (p = 0.0146), although did not maintain the proper functioning of the auditory system. We, therefore, conclude that conditioning with a different agent from that used to cause the trauma is effective, which suggests that both agents that were used promote similar mechanisms of self-protection.