Orthopaedic Associates of Wisconsin, Pewaukee, Wisconsin.
Department of Orthopedics and Rehabilitation (M.A.H. and K.J.N.), University of Wisconsin School of Medicine and Public Health (K.G.), Madison, Wisconsin.
J Bone Joint Surg Am. 2018 Apr 18;100(8):e49. doi: 10.2106/JBJS.17.00389.
The act of applying, univalving, and spreading a plaster cast to accommodate swelling is commonly performed; however, cast saws can cause thermal and/or abrasive injury to the patient. This study aims to identify the optimal time to valve a plaster cast so as to reduce the risk of cast-saw injury and increase spreading efficiency.
Plaster casts were applied to life-sized pediatric models and were univalved at set-times of 5, 8, 12, or 25 minutes. Outcome measures included average and maximum force applied during univalving, blade-to-skin touches, cut time, force needed to spread, number of spread attempts, spread completeness, spread distance, saw blade temperature, and skin surface temperature.
Casts allowed to set for ≥12 minutes had significantly fewer blade-to-skin touches compared with casts that set for <12 minutes (p < 0.001). For average and maximum saw blade force, no significant difference was observed between individual set-times. However, in a comparison of the shorter group (<12 minutes) and the longer group (≥12 minutes), the longer group had a higher average force (p = 0.009) but a lower maximum force (p = 0.036). The average temperature of the saw blade did not vary between groups. The maximum force needed to "pop," or spread, the cast was greater for the 5-minute and 8-minute set-times. Despite requiring more force to spread the cast, 0% of attempts at 5 minutes and 54% of attempts at 8 minutes were successful in completely spreading the cast, whereas 100% of attempts at 12 and 25 minutes were successful. The spread distance was greatest for the 12-minute set-time at 5.7 mm.
Allowing casts to set for 12 minutes is associated with decreased blade-to-skin contact, less maximum force used with the saw blade, and a more effective spread.
Adherence to the 12-minute interval could allow for fewer cast-saw injuries and more effective spreading.
应用、分开并展开石膏夹板以适应肿胀的操作很常见；但是，使用石膏锯可能会对患者造成热损伤和/或磨蚀损伤。本研究旨在确定分开石膏夹板的最佳时间，以降低石膏锯损伤的风险并提高展开效率。
将石膏夹板应用于真人大小的儿科模型上，并在设定的 5、8、12 或 25 分钟时分开。评估指标包括分开时施加的平均和最大力、刀片与皮肤的接触次数、切割时间、展开所需的力、展开尝试次数、展开的完整性、展开距离、锯片温度和皮肤表面温度。
与设置时间<12 分钟的石膏夹板相比，设置时间≥12 分钟的石膏夹板的刀片与皮肤接触次数明显减少（p<0.001）。对于平均和最大锯片力，各个设定时间之间没有显著差异。但是，在较短组（<12 分钟）和较长组（≥12 分钟）之间的比较中，较长组的平均力较高（p=0.009），但最大力较低（p=0.036）。锯片的平均温度在各组之间没有差异。“爆开”或展开石膏夹板所需的最大力在 5 分钟和 8 分钟的设置时间更高。尽管需要更大的力来展开石膏夹板，但在 5 分钟时有 0%的尝试和在 8 分钟时有 54%的尝试成功完全展开了石膏夹板，而在 12 分钟和 25 分钟时有 100%的尝试成功。在 12 分钟的设置时间下，展开距离最大，为 5.7 毫米。
将石膏夹板放置 12 分钟可减少刀片与皮肤的接触，使用锯片时的最大力降低，并且展开效果更好。
遵守 12 分钟的间隔时间可能会减少石膏锯伤并提高展开效果。
