Effect of Casting Material on the Cast Pressure After Sequential Cast Splitting

Area of Science:

• Orthopedics
• Biomaterials Science
• Clinical Engineering

Background:

• Circumferential casting is crucial for nonoperative fracture management.
• Casts are often valved to reduce pressure and prevent complications from swelling.
• Limited data exists on how casting materials influence internal cast pressure.

Purpose of the Study:

• To investigate the effect of different casting materials and padding on pressure within long-arm casts.
• To determine which cast padding type provides the most significant pressure reduction after bivalving.

Main Methods:

• Seventy-five long-arm casts were created on volunteers, divided into five groups based on cast material (plaster/fiberglass) and padding (cotton, synthetic, waterproof).
• A pediatric blood pressure cuff bladder was inflated to 100 mm Hg within each cast.
• Pressure readings were recorded after sequential release stages: cast bivalve, padding release, and stockinet release.

Main Results:

• Cast type did not affect pressure changes; however, cast padding significantly influenced internal pressures.
• Waterproof padding showed the highest sustained pressures, followed by synthetic padding.
• Cotton padding consistently demonstrated the lowest pressure readings across all measurement points.

Conclusions:

• The type of cast padding is a significant determinant of pressure within a long-arm cast, even after bivalving.
• Cotton cast padding allows for the greatest pressure reduction, making it suitable for acute fracture management.
• Synthetic and waterproof padding are not recommended for acute fractures due to their tendency to retain pressure.