@article{oai:nagoya.repo.nii.ac.jp:00015389, author = {SUZUKI, ASAKATSU and NAMBA, YOSHIMICHI}, issue = {1-2}, journal = {Nagoya Journal of Medical Science}, month = {Nov}, note = {We have been sterilizing the operating microscope and flexible fiber-optic illuminator on a mobile stand by formaldehyde gas at ambient temperature for the past four years. The instruments were wrapped in two polyvinyl bags and 60 g of formaldehyde-adsorbed plaster were placed in the bottom of the bags. The efficiency of this sterilizing procedure has been periodically tested by examination with spores of Bacillus subtilis and Bacillus stearothermophilus. Of the 245 tests 17 (6.9%) showed positive growth of bacterial spores, the exposure time of the positive growth ranging from 10 hrs and 30 min to 68 hrs and 15 min. The positive growth rate was markedly higher in the operating microscope than in the flexible fiber-optic illuminator. However, after January of 1980 the exchange interval of the formaldehyde-adsorbed plaster was shortened from 4 to 2 weeks, and as a result, all tests longer than a 25-hr exposure time showed negative growth. Therefore, we concluded that a 24-hr exposure time is satisfactory to obtain sterility of the instruments with this method.}, pages = {43--48}, title = {Sterilization of Operating Microscope and Flexible Fiber-Optic Illuminator by Formaldehyde Gas}, volume = {45}, year = {1982} }