Page 118 - Manual of Equine Field Surgery

114 LIMB SURGERIES

Figure 19-1 Supplies used in cast application. From Figure 19-4 A cast where all layers have cured

left to right, stockinette, orthopedic felt, foam cast simultaneously,

padding, and fiberglass casting material.

Figure 19-2 Applying a double layer of stockinette. Figure 19-5 A cast where individual layers of cast

material have cured separately. The result is a weak cast

prone to break.

water. Specific directions for handling vary with

each manufacturer. Generally, the cast material is

immersed in water at room temperature ( 68° to

77° F, 20° to 25° C) and squeezed four to five times

while immersed, before application. Cast material

curing time can be slowed slightly by exposing the

material to cooler water for a shorter time period.

As cast material cures, it stiffens to provide rigid

support. All layers of the cast should cure simul-

taneously to provide adequate strength. Once cast

application is begun, subsequent layers of cast

tape must be applied rapidly to avoid individual
Figure 19-3 Orthopedic felt applied at the antici-

pated proximal limit of the cast. layers of cast material stiffening before becoming

bonded to the surrounding layers (Figures 19-4

Handling of Cast Material and 19-5).

The strength of a cast depends on the thickness of Application of Cast Material

the cast and the bonding between the individual

layers of cast tape. The polyurethane resi11 iI1 the A layer of cast padding is applied before the cast

casting tape starts to cure when immersed in material is applied to ensure even contact between