Understanding Noise Exposure During Cast Removal: The Effect of Cast Saw Type and Casting Material

Cast removal can be associated with considerable noise exposure, especially impacting the pediatric patient and provider. Although noise generation from cast saws has been deemed safe by the U.S. Occupational Safety and Health Administration and the U.S. Centers for Disease Control and Prevention standards, there are no current studies on the effects of cast material on noise levels generated.

A simulated casting model utilizing plaster, fiberglass, and plaster with fiberglass overwrapping was used for experimental testing. Four different casting conditions were tested, with 5 samples in each group. Samples were tested using 2 different cast saws: a standard cast saw and a quiet saw. Each saw was used for 30 seconds of continuous cutting for each sample, measuring peak, mean, and minimum sound levels in decibels with sound level meters. Noise levels were measured at 18, 36, and 72 in (20, 91, and 183 cm) from the saw, comparing saw and cast types against ambient noise and baseline cast-saw noises. Between-group comparisons were performed using univariate analyses.

Mean noise generation differed between casting materials, with plaster material demonstrating significantly greater noise levels than fiberglass casts at all distances for each saw type. Increasing fiberglass thickness significantly increased the mean noise levels with standard (18-in distance for 10 and 5 ply: 87.4 and 85.8 dB; p = 0.0004) and quiet cast saws (78.3 and 76.1 dB; p = 0.041. Additionally, the quiet cast saw provided a 5.7 to 10.6 dB reduction in mean and peak noise levels, varying by casting material and distance.

Occupational noise exposure can be mitigated with the use of fiberglass casting material that is not >5 ply in thickness, with a quiet cast saw for removal. The use of a quiet cast saw substantially decreased noise exposure to patients and staff members over standard orthopaedic cast saws.