Use of quiet cast saw for cast removal lowers noise exposure compared to standard orthopaedic cast saws

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.

Aaron Shaw et al conducted the study at the Department of Orthopaedic Surgery, Dwight D. Eisenhower Army Medical Center, Fort Gordon, Georgia. It has been published in ‘the journal of bone & joint surgery.’

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.

Key findings of the study were:

• 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).

• 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.

The authors concluded that – “this study demonstrated that casting material and cast quality exhibit a significant influence on noise generation during cast removal. Fiberglass material produces significantly lower noise levels in comparison with plaster casting material during cast removal, and increasing cast thickness increases noise levels. These between-group differences, however, can be mitigated by incorporating quiet cast saws for removal, which also significantly reduce occupational noise exposure. As such, we recommend that providers pay close attention to casting material thickness during cast application to mitigate the risk of both unnecessary noise exposure and thermal injury. Although all casting groups did not exceed threshold noise exposure levels, we suggest the application of ALARA principles to noise exposure by consideration for either use of quiet cast saws during cast removal or the incorporation of patient and provider hearing protection to mitigate the occupational risk of noise-induced hearing loss.”

Further reading:

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

K. Aaron Shaw, Casey Mueller et al

TH E JOURNAL OF BONE & JOINT SURGERY- JBJS.ORG

VOLUME 104-A, NUMBER 17, S EPTEMBER 7, 2022

http://dx.doi.org/10.2106/JBJS.22.00158