Patient population
Data was retrospectively collected at a single institution from 2009, July to 2018, January. The inclusion criteria are patients diagnosed of chronic focal myringitis with the symptoms signs for more than one month. We treated those enrolled with ear drop, containing Boric acid, Alcohol and Glycerin Ear Drop (BAAG) otic solution three drops once and three times daily for at least one month. If symptoms persisted or only partial clinical improvement, surgical treatment was implied. The surgery group were divided into the CO2 laser and caustic agent cauterization with trichloroacetic acid (TAA). The flow chart of data collection was presented in figure. 1. The distribution of CO2 laser and TAA cauterization were all randomized. Both the CO2 and TAA group were carried out by a single surgeon under microscope in the operation room, with the record document by the rotated residency at the “Blinded for review”. The excluded criteria were described as below: (1) the patients who had diffused granular myringitis; (2) the disease involve middle ear cavity or external ear canal; (3) accepted surgical treatment differ from CO2 laser or TAA cauterization; (4) those who had loss followed-up after surgery or refused surgical treatment. We defined the successful criteria as no granulation tissue noted in local finding and symptom improved with post-operative follow up at least four months. If local findings showed granulation tissue again and symptom relapsed within four months to a year after surgery, it will be regarded as recurrence. At last, if symptoms show up again or clinically discover granulation on tympanic membrane after a year after the surgery, we consider it a new onset.