A cast saw is an oscillating power tool used to remove orthopedic casts. Unlike a circular saw with a rotating blade, a cast saw uses a sharp, small-toothed blade rapidly oscillating or vibrating back and forth over a very small angle to cut material. This device is often used with a cast spreader.
The patients' skin frequently comes into contact with the cast saw blade without cutting although it can cause lacerations when used over bony prominences. The design enables the saw to cut rigid materials such as plaster or fiberglass while soft tissues such as skin move back and forth with the blade, dissipating the shear forces, preventing injury. A general technique in the use of cast saw often involves a demonstration before actually cutting the cast. 
Cast removal procedures result in complications in less than 1% of patients. These complications can include skin abrasions or thermal injuries from friction between the saw and cast. Temperatures exceeding 101 °C (214 °F) have been recorded during removal of fiberglass casts. Proper use of the saw is to perforate (instead of cutting) the cast, which can then be separated using a cast spreader.
Alternatives include cast cutting shears which were patented in 1950 by Neil McKay.
- "Do You Know How to Safely Remove a Cast Easily?". Verywell Health. Retrieved 2018-03-25.
- Dresing, Klaus; Trafton, Peter G. (2014-12-17). Casts, Splints, and Support Bandages: Nonoperative Treatment and Perioperative Protection. Thieme. ISBN 9783131753519.
- Staheli, Lynn (2008). Fundamentals of Pediatric Orthopedics. Philadelphia: Lippincott Williams & Wilkins. p. 51. ISBN 9780781774970.
- Halanski, Matthew A. (June 2016). "How to Avoid Cast Saw Complications". Journal of Pediatric Orthopaedics. 36: S1–S5. doi:10.1097/BPO.0000000000000756. ISSN 0271-6798. PMID 27152901.
- Swiontkowski, Marc; Stovitz, Steven (2013). Manual of Orthopaedics. Philadelphia: Lippincott Williams & Wilkins. p. 149. ISBN 9781451115925.
- Plaster cast cutter, 1945-04-02, retrieved 2018-03-25
- US 2602224, McKay, Neil, "Plaster cast cutting shears", published 28 August 1950, issued 8 July 1952