Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates generally to orthopedics
and more specifically to an improved orthopedic cast and method
of constructing same.
Plaster casts have been used in the healing
arts for many years to immobilize and hold in place a fractured
bone. Construction of a plaster cast is a time consuming pro-
cedure requiring a high degree of skill~ Normal procedure is
for the dry plaster ingredients to be impregnated in a gauze
cloth to form what is commonly referred to as a plaster splint. -
After the fractured bone is set in place, and the attendant
portion of the body is covered with a soft cloth, a number of
the plaster splints are moistened and carefully wrapped around
the body portion. A minimum of six and as many as fifteen or
twenty splints are utilized to form a multiple layered immobil-
izing cast. As each splint must be moistened and then carefully
laid over the preceding splint followed by wrapping of the
splint around the body portion, this is a very time consuming
procedure. The person applying the cast must be very careful
to control the amount of moisture applied to the individual
splints as too much moisture will weaken the cast and too little
moisture will result in non-adherence of the individual splints
to each other which also causes a weak spot.
Because of the great amount of time as well
as skill that is required to construct a conventional plaster
cast, it has been impossible to utilize such casts on an emer-
gency basis to immobiliæe a broken bone at the scene of an acci-
dent. ~hile in many instances such temporary immobilization
would greatly facilitate transfer of the patient to a medical
center and possibly prevent further and more serious injury,
it has not been possible to utilize plaster casts on such an
emergency basis.
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It is therefore a primary object of the present
invention to provide an immobilizing orthopedic cast which can
be constructed in a fraction of the time as required for a con-
ventional plaster cast and can therefore be utilized on an emer-
gency and temporary basis at the scene of an accident for facil-
itating transfer of the patient to a medical center.
As a corollary to the above object, it is an
important aim of this invention to provide an immobilizing
orthopedic cast which can be constructed by paramedical personnel
having a minimal amount of training as compared with the amount
of training necessary for a person to be qualified to construct
a conventional plaster cast.
An important object of the invention is to pro-
vide an orthopedic cast and method of constructing same wherein
plaster is encased between two layers of highly absorbent flex-
ible material, one layer of which is of a cellular construction
to promote water absorption and the other layer of which is
of fiber construction to provide reinforcing strength to the
cast.
As a corollary to the above object, one of the
objectives of the invention is to provide an immobilizing ortho
pedic plaster cast and method utilizing a plaster blank wherein
one side of the blank is constructed from a fibrous material
and the other side of the blank is constructed from a resilient
cellular material having a non-affinity for moistened plaster
whereby the latter mentioned side will readily absorb and hold
water and will forma resilient cushion for placing next to the
wearer's body.
It is still another objective of our invention
to provide an orthopedic cast which is easier and quicker to
construct than a conventional plaster cast and is also more
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comfortable forthe patient to wear because of the incor-
poration into the cast as an integral part of a resilient layer
of material between the rigid plaster and the patient's body.
Another one of the objectives of our invention is
to provide an orthopedic cast which may be utilized to set
a fracture and may also be utilized to immobilize or support
portions of the body such as in the cervical or lumbar regions.
Still another object of this invention is to pro-
vide a method of constructing a cast for permanently setting
a fractured bone that is easier for a doctor to utilize
because of the elimination of the multiple steps required in
building a multiple layered cast from individual splints.
In one aspect of the invention there is provided a ~-
method of constructing a casting blank from which a plaster
cast for a portion of the body may be formed, said method
comprising: providing a first outermost sheet of resilient,
cellular, substantially non-extensible water absorptive
material characterized by a non-affinity for moistened plaster;
depositing a quantity of plaster on said first sheet; pro-
viding a second outermost sheet of deformable water absorptive
material; placing said second sheet in overlying relationship
to the plaster on said first sheet; and joining the peripheral -
edges of said first and second sheets to encase said plaster
therewithin.
In a further aspect of the invention there is
provided a casting blank for use in forming a plaster
cast for a portion of the body, said blank comprising: a
first sheet of resilient, cellular, substantially non-exten-
sible water absorptive material characterized by a non-
affinity for moistened plaster; a layer of plaster materialdisposed on said first sheet; and a second sheet of deform-
able, water absorptive material disposed in overlying relation-
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ship to said plaster material to sandwich the latter between
said first and second sheets, said first and second sheets
being joined together at their peripheral edges to enclose
said plaster material within said deformable water absorptive
material.
In the drawings:
Fig. 1 is a top plan view with portions broken
away of a casting blank constructed according to the present
invention for use in the inventive method of constructing
a cast;
Fig. 2 is a perspective view illustrating how the
casting blank would be placed to form a cast around the
ankle and foot;
Fig. 3 is a side elevational view of the ankle
and foot shown in Fig. 2 with the casting blank shaped to
conform to the shape of this portion of the body;
Fig. 4 is a side elevational view of a portion of
the elbow and upper and lower arm of a person encased within -~
a cast constructed according to the teachings of the present
invention;
Fig. 5 is a side elevational view, similar to
Fig. 4, and illustrating a further step which may be utilized
in constructing a cast according to the method of the present
invention; and
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Fig. 6 is another side view of the arm and el-
bow shown in Figs. 4 and 5 with the completed cast therearound.
Referring initially to Fig. 1, the present in-
vention encompasses a novel casting blank 10 and a method of
constructing it. A first sheet 12 of deforrnable water absorptive
resilient material is placed on a working surface and trimmed
to an appropriate size. Even though resilient and deformable
in a direction corresponding to its thickness, sheet 12 should
be substantially non-extensible in the directions of its length
and width. A number of plaster splints 14 are then placed over
sheet 12 in general alignment with the latter. Each splint 14
is of a construction well known to those skilled in the art and
normally comprises a layer of gauze cloth impregnated with the -~
dry plaster ingredients. It is to be understood, however, that
the term "plaster splint" as used in this application is intended
to include any plaster-like material which will harden after
water has been added, impregnated in a carrier such as the gauze
cloth. While it is much preferred to utilize the plaster splints
14, for some applications it is possible to utilize dry plaster
ingredients without the cloth carrier strips.
The number of plaster splints 14 may also b~
varied in accordance with the requirements for the particular
cast being constructed. For most applications at least six of
the splints 14 will be required to give the necessary support
and additional splints may be utilized as needed.
A second sheet 16 of water absorptive deformable
material is trimmed to the appropriate size and placed over
the splints 14 on the first sheet. The sheets 12 and 16 are
each of a size such that they present a surface area larger
3~ than the surface area of the splints 14 so that the edges of
the sheets extend beyond the edges of the splints. Both of sheets
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12 and 16 are formed from a water absorptive deformable material.
Both sheets 12 and 16 are substantially non-extensible as explain-
ed for sheet 12 previously. A preferred construction for many
applications is to use a first sheet of resilient non~extensible
cellular construction, such as foam rubber, and a second sheet
of fiber material, such as flannel cloth. The foam rubber mate-
rial will absorb water very rapidly thus facilitating wet-out
of the plaster. The foam rubber is also a material to which
the plaster will not adhere thus prov ding a comfortable resilien-t
~0 padding to be placed next to the wearer's body. The flannel
material, on the other hand, while also being non-extensible,
readily absorbs a quantity of plaster and the latter becomes
embedded within the fibers of cloth. The fibers serve as rein-
forcing strands which significantly increase the strength of
the completed cast. In other applications it may be desirable
to construct both layers of flannel or other fiber material.
In still other applications a construction utilizing two layers
of cellular material may be desired.
Next, the edges of sheets 12 and 16 are joined
together through use of a suitable adhesive, or other appropriate
means. The completed casting blank 10 will thus comprise upper
and lower layers of a deformable water absorptive material (ei-
ther the same material or different material) with a quantity
of plaster sandwiched between the two layers. It has been found
helpful to provide a centering ring 18 imprinted on the surface
of one of the sheets to facilitate centering of a portion of
the body such as foot 20 to be enclosed within the cast formed
from blank 10.
When a cast is to be constructed from blank
10, the latter is saturated with water to activate the chemical
reaction that will harden the plaster. Because splints 14 are
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enclosed within sheets 12 and 16, the amount of water utilized
is easier to control. Generally, by submerging blank 10 for
from 20 to 40 seconds (until the dry plaster becomes soft) the
sheets 12 and 16 will become saturated and an adequate but not
excessive quantity of water is available for splints 14. Excess
water is drained and pressed from blank 10 before the latter
is moved into position for shaping around foot 20. The blank
is shaped around the foot to conform to the shape of the latter
by folding and "kneading" it into place. The completed cast
as illustrated in Fig. 3 and designated by the numeral 22 will
normally harden in ten minutes or less although this time may
be accelerated by the application of warm air.
The blank 10 is illustrated in Fig. 3 shaped
into an elbow cast 240 It will generally be preferred for a
cast formed from blank 10 to be wrapped with tape 26 to hold
the cast in place while it is drying. Tape 26 may be an inelas-
tic adhesive type or may comprise an elastic material commonly
referred to as an elastic bandage. The tape remains in place
after the plaster cast hardens and provides some additional sup-
port for the cast as well as a degree of protection against dam-
age. As a final dressing for the cast, a stockinette 28 may
be pulled over the tape 26. Manifestly, stockinette 28 may be
easily removed and washed as required.
While the foregoing method has been described
with particular reference to use of a cast in immobilizing a
fractured bone, the economy and simplicity of a cast constructed
according to the present invention makes it readily usable in
the lumbar and abdominal regions for support purposes. It may
also be used in the cervical area to provide support and immo-
bilization to a degree not heretofore possible with conventional"collars", yet in situations which would not justify the place-
ment of a conventional cast.
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In another novel application of plaster casts
made possible by the present invention a girth-type band is pro-
vided for wearing around the waist of a patient~ A pocket in
the lumbar region receives a cast formed from a casting blank
and using the method of the present invention. In this manner
support and immobilization of the back is achieved to an extent
previously not possible unless a large, uncomfortable cast was
utilized. In any use of the cast, after hardening it may be
cut into for examination of the injured area and then replaced
by wrapping tightly with tape.
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