A fiberglass cast is the plaster cast made from fiberglass material which is s a lighter, synthetic alternative plaster of Paris. Fiberglass is also called glass-reinforced plastic[GRP] or glass fiber reinforced plastic [GFRP] is a fiber reinforced polymer made of a plastic matrix reinforced by fine fibers of glass.
The fiberglass cast is also popularly called the synthetic cast. Traditionally, the orthopedic cast has been made of plaster of Paris and is called plaster cast.
A fiberglass cast is a lightweight and extremely strong material. As compared to traditional plaster of Paris cast, it is light in weight and more durable. It is three times stronger and but is only one third in weight.
Casts made of this material require less maintenance than those made with plaster.
Plaster of Paris casts is white in color. Fiberglass casts come in many colors and some doctors even let the patient choose the color.
Fiberglass cast, like its plaster of Paris counterpart, is applied in case of fracture treatment. The fiberglass cast, however, is not applied in acute settings because this cast is less accommodating to swelling or where the reduction of the fragments necessitates molding. But there are some reports of authors reporting that it is safe to apply fiberglass cast in an acute setting also.
The fiberglass cast is less yielding to molding and to hold fracture fragments, molding is required. In contrast, the plaster of Paris provides excellent molding.
Therefore fiberglass cast is used mostly in those cases where the healing process has already begun, acute period of injury has passed and fractures which are not displaced.
Fiberglass sets quickly, therefore experience is required to time the application well. It is hygroscopic [absorbs water] and setting time decreases with humidity and warmth.
Another aspect that needs to be looked into is the expense. Typically a fiberglass plaster bandage costs more than plaster of Paris bandage but the number of bandages required in a given setting is less.
Despite the cost of a plaster of fiberglass being more than traditional plaster of Paris cast.
Indications for Fiberglass Cast or Splint
The usage profile of fiberglass cast or splint is similar to that of plaster of Paris cast or splint.
But as I mentioned before, the fiberglass material is used less for splint purposes due to the costs involved.
The use of fiberglass cast or splint can be considered in the following situations.
- A temporary splint
- For joint immobilization in ligament injury
- Joint swelling due to disease.
- For fractures.
- Definitive treatment of fractures or ligament injury
- External splint after surgery
- Blocking movements in case of nerve, tendon or vessel repair.
- After osteotomies
- Providing rest to limb or part in case of disease
Fiberglass cast application
- Fiberglass bandages of appropriate size
- Available in a range of 1inch – 6 inches
- The width used is determined by the width of the limb, roughly
- Water at room temperature
- Stockinette of an appropriate width
- Cotton wrap
- Cotton bandages for splinting
- Gloves for applier and assistance
- Protective linen for patient
- Position the patient
- For upper limb – sitting or supine position
- For lower limb – supine or prone
- Apply the stockinette. Extend proximally and distally beyond the limits of where the extent of the cast.
- Over this, a cast padding is wrapped. Take special care to cover the bony prominences.
- Fold both ends of the stockinette sleeve over the cast padding to give attractive well-cushioned ends to the cast.
- The physician and assistants wear gloves [synthetic casting materials can create exfoliative dermatitis when exposed to bare skin or the applier may have allergic reactions to the material]
- Position the limb in the desired position. For example, in the lower limb, short leg cast, the foot is kept in the neutral position mostly but depending on the injury it may be in plantar flexion as well.
- Next, a roll of synthetic cast material is removed from its packaging while the limb is kept in the desired position by assistants.
- Some people apply it after immersing in the water while others apply it directly without immersing.
- In the latter cases, the water is sprinkled over the applied synthetic bandage.
- In very humid environments, the synthetic material, being very hygroscopic absorbs water from the surrounding and extra water may not be required.
- As it is applied, it should be stretched, allowed to relax, and then laid on the limb. The bandage should not be applied in tension. The desired number of bandages are applied depending on limb position, circumference and extent of the cast.
- After some time, the cast material will begin to harden with the exothermic reaction.
Here are two videos on fiberglass cat application.
Fiberglass cast application – Short arm cast
Fiberglass cast application – Leg cast
Care of the Applied Fiberglass Cast
All the casts in case of acute fractures should be recalled the next day to note any discomfort, bluishness, swelling and numbness of the digits.
[Read in detail about the care of the plaster cast]
Here are the basic DOs and DON’Ts of the fiberglass cast [also for other types of casts]
- Do not wet, cut, heat or otherwise interfere with this plaster.
- Report immediately if a problem arises
- Plaster cracks or becomes loose or uncomfortable.
- A pain that is not relieved or worsens
- Discharge or high-grade fever
- Numb fingers or toes
- Swollen or blue digits
- An unrelenting burning sensation at any point throughout the cast extent.
- Elevate the limb as instructed especially for the first 24 hours
- Move the fingers or toes continuously
- Encourages the return of the blood
- Reduces swelling
- Keep the cast clean and dry.
- Pad the rough edges to protect the skin from scratches.
- Do not scratch the skin under the cast by inserting objects inside the cast.
- Instead one can use a hairdryer placed on a cool setting to blow air under the cast
- Do not put powders or lotion inside the cast.