Orthopaedic PresentationPLASTER OF PARIS (POP) By: Muhammad Syafiq Hilmi Musa Ahmad Soufi Ahmad Fuad
What is Plaster of Paris? Plaster – basic building material for coating walls and ceilings. Starts as a dry powder, harden when applied together with water and heat. Different type – − Plaster of Paris (Gypsum) − Lime plaster − Cement plaster
Different type use in different setting. As in architecture, art, fire protection and even in medicine. Plaster of Paris is widely used in Medical setting espescially in Orthopaedic department. POP results from the calcination of gypsum or calcium sulfate dihydrate (CaSO4, 2 H2O), which partially dehydrates to produce a hemi- hydrate (CaSO4 , ½ H2O).
History- The term plaster of Paris was first used in the 17 th century due to large quarry deposits of gypsum located in Montmartre, a district of Paris. They mostly use them for sculpturing, decoration and surface for painting.- But researcher has found plaster wall and artifacts for interior of Great Pyramids. This prove usage of plaster has been since ancient times.- Invention of plaster bandage can be attributed to Arabic doctor in 1000 C.E. (Al-Tasrif). But POP bandages were first used by Matthysen, a Dutch military surgeon in 1952.
Indication of Plaster Usage1) Chronically stiff joint.2) Hard end feel contractions of any joint. Secondary to: - fracture, amputation, tendon rupture, lacerations or repair, nerve repairs and burns3) Deformity.
Plaster Type1) Plaster of Paris (POP) - Roll of muslin stiffened by dextrose or starch and impregnated with hemihydrate calcium sulfate. - It is cost-effective, non allergic and easy to mould. - But it is heavy and fragile if contact with water.2) Fibreglass - Strong but lighter than Plaster of Paris. - It is cool, water resistant and radiolucent. - But it is more expensive.
Cast Application- Clean skin and apply dressing if there is wounds. Apply uniform thickness of cotton padding- Soak plaster roll in water at room temperature- Gently pick up the ends of the bandage with both hands and lightly squeeze it, pushing the ends together without twisting or wringing
- Hold relevant body part steady in correct position- Apply the plaster by unrolling the bandage as it rests on the limb. Overlap the previous layer of plaster by about half the width of the roll- Mould the plaster evenly, rapidly and without intervention. Rubs each layer firmly with the palm so that the plaster forms a mass.- Mould until firm and let it completely dry for 24 hours.- Same methods goes with fibreglass type plaster.- For removal, we can use plaster shears or electric saw.
Types of Cast1) Bivalved - Can be removed, secured with Velcro2) Drop out cast - part of the extremity can be moved3) Cylindrical cast - typical fracture cast4) Weight bearing casts - to hold extremity in position to assist in weight bearing
Short leg patella tendon bearing cast Typical Cast Long arm castMinerva jacketCylinder cast Short arm thumb spica cast Hip spica cast
ComplicationsDue to tight cast: Due to improper- Pain application:- Pressure sore - Joint stiffness- Compartment - Blisters and soressyndrome - Breakage- Peripheral nerve injury Others: Due to plaster allergy: - Deep vein trombosis - Allergic dermatitis (DVT)
Advice to patients- Do not get the cast wet. Use plastic bags to cover the cast while bathing.- Do not walk on the cast.- Do not stick anything down to the splint to scratch or itch. This may lead injury and infection.- Instruct patient to return if there is numbness, tingling, increase pain and impaired sensation.