Cast saw noise does not reach occupational hazard levels.

Post, Joel M; Switzer, Kyle D; Brown, David K; Meinzen-Derr, Jareen; Dively, Jennifer; Dunkin, Bradley S; Mehlman, Charles T

BACKGROUND The purpose of our study was to measure the sound level generated by selected commercially available cast saws. These levels were then compared with the level of everyday sounds and to accepted intensities by Safety Administrations to see whether the mandatory use of hearing protection should be recommended to prevent noise-induced hearing loss. METHODS We assessed the sound levels generated by the Quiet Cast Removal System (QCR; OrthoPediatrics Corp., Warsaw, IN), Stryker 986 Cast Vac (Stryker Corp.), and the Stryker 840 Cast Cutter (Stryker Corp.). The sound generated by these saws was measured with a sound level meter at the source and at 6, 12, and 36 inches. The sound level from each device was assessed both while operating alone and while cutting casts for a total of 3 repetitions at each of the distances tested and analyzed statistically. RESULTS The maximal mean sound intensity of the Stryker 986 and Stryker 840 saws was 90.7 and 88.6 dBA at 36 inches, respectively while cutting a cast, whereas the QCR System produced 50.1 dBA at this distance. At 6 inches, the mean sound intensity was 99.4, 96.4, and 64.5 dBA for the Stryker 840, 986, and QCR, respectively. Statistically significant differences in sound intensity between Stryker and QCR saws were noted under all testing scenarios (P<0.0001). CONCLUSIONS None of the cast saws produced intensities exceeding recommended standards for a single exposure or intensities reaching occupational hazard levels. The QCR saw was significantly quieter than both the Stryker 840 and 986 under all scenarios. The need for a recommendation of mandatory usage of hearing protection for patients and office personal could not be demonstrated. CLINICAL RELEVANCE Cast saw noise is common in orthopaedic clinics. Our study demonstrates sound levels from commercially available saws do not reach occupational hazards but are sufficiently high that practical methods to reduce intensity may be warranted.