Myringosclerosis develops within 9 h of myringotomy

The aim of the present experimental study was to elucidate the temporal dev elopment of myringosclerosis. Twenty-four Sprague-Dawley rats were myringot omized bilaterally. At 3, 6, 9, 12, 18, 24, 30, 36, 48, 60, 72 and 84 h aft er the myringotomy, 2 animals at each time were examined otomicroscopically and thereafter sacrificed. The pars flaccida and pars tensa were excised a nd prepared for light- and electron-microscopic studies. Otomicroscopically , myringosclerosis was visible in the pars tensa 24 h after myringotomy, wh ereas no sclerotic lesions were noted in the pars flaccida. Histologically, sclerotic lesions were present in the pa rs tensa and pa rs flaccida 9 and 12 h, respectively, after myringotomy. The pars flaccida responds promptly with an inflammatory reaction characterized by abundant macrophages. Myrin gosclerosis develops promptly after myringotomy and its establishment is re lated to an inflammatory reaction.