US 3656475 A
Process for applying a novel lightweight, X-ray transmissive orthopedic cast to an injured member in a convenient manner and in an amount of time less than conventional casts. A tubular knitted fabric base sleeve is drawn over the portion of the member being treated. An inert, impermeable barrier layer is provided thereover to space said base sleeve from an outer tubular knitted fabric sleeve which is drawn over said base sleeve. The out sleeve is impregnated, at least at its surface, with a liquid composition capable of setting in a rapid manner to form a rigid resin, e setting of said resin rendering said outer sleeve rigid.
Description (OCR text may contain errors)
llnited States Patent Hanrahan, Jr.
 3,656,475 [451 Apr. 18, 1972  ORTHOPEDIC CAST AND PROCESS FOR APPLYING SAME  Inventor: James R. Hanrahan, Jr., 45 Sturges Road,
Fairfield, Conn. 06430  Filed: Mar. 5, 1970  Appl. No.: 16,907
Related U.S. Application Data  Continuation-impart of Ser. No. 81 1,766, Apr. 1,
 U.S. C1 ..128/90  Int. Cl...... ..A6lf5/04  Field of Search ..128/90, 91, 89
 References Cited UNITED STATES PATENTS 2,853,067 10/1958 Puharich ..128/90 2,947,307 9/1960 Hoppe ....128/90 3,307,537 3/1967 Simon et al.... ....128/90 3,301,252 1/1967 Mahoney ....128/90 3,089,486 5/1963 Pike 128/90 2,960,984 11/1960 Parker 1 28/91 FOREIGN PATENTS OR APPLICATIONS 657,419 3/1961 Canada ..l28/90 Primary ExaminerRichard A. Gaudet Assistant ExaminerJ. Yasko Attorney-Johnson and Kline  ABSTRACT Process for applying a novel lightweight, X-ray transmissive orthopedic cast to an injured member in a convenient manner and in an amount of time less than conventional casts. A tubular knitted fabric base sleeve is drawn over the portion of the member being treated. An inert, impermeable barrier layer is provided thereover to space said base sleeve from an outer tubular knitted fabric sleeve which is drawn over said base sleeve. The out sleeve is impregnated, at least at its surface, with a liquid composition capable of setting in a rapid manner to form a rigid resin, e setting of said resin rendering said outer sleeve rigid.
16 Claims, 4 Drawing Figures PATENTEDAPR 18 m2 'INVENTOR. James R Han/2172a, Jr
ATTORNEYS ORTHOPEDIC CAST AND PROCESS FOR APPLYING SAME This application is a continuation-in-part of parent application Ser. No. 81 1,766, filed Apr. 1, 1969, now abandoned.
Orthopedic casts, sometimes referred to as splints, braces, supports, or the like, have been proposed as replacements for the conventional plaster casts which are in common usage. It has long been recognized that plaster casts are disadvantageous in many respects. They require a length of time to apply and to set. They are heavy and thick and thus are burdensome and inconvenient for the wearer. They are not completely permeable to X-rays and thus retard examination of the progress of the treatment.
It has been proposed to overcome these disadvantages by providing resinous orthopedic casts. However such proposals have not met with commercial success, primarily because they are difficult to apply and require complicated application devices, and because they introduce new problems and dangers to the patient, so that the plaster cast remains as substantially the only orthopedic cast in use today. Substantially all resinous or resin-forming compositions have dermatological toxicity to some extent and thereby can produce serious skin irritation on application and/or on prolonged contact with the skin. Foamed resins have been suggested but these produce bulky casts and/or require rigid reinforcements which add to the weight and complicate the application of the casts.
It is the principal object of the present invention to provide novel orthopedic casts which represent a substantial improvement over conventional plaster casts both with respect to ease of application and comfort, convenience and safety of the wearer, and which do not have the disadvantages of the plastic or resinous orthopedic casts proposed in the past.
It is another object of this invention to provide a lightweight orthopedic cast which can be applied and set in substantially less time than required for other known casts and with a minimum amount of equipment whereby use under adverse conditions, such as on the battlefield, is completely practical.
It is still another object of the invention to provide an orthopedic cast which can be applied to an injured member in a rapid manner without subjecting the injured member to undue stress, and which permits the cast to be repositioned in simple manner prior to the setting operation, if such is required, as may be determined by means of an X-ray.
These and other objects and advantages of the present invention will be clear to those skilled in the art in the light of the present disclosure, including the drawings, in which:
FIG. 1 is a perspective view of an apparatus for r applying a barrier layer to a tubular knitted fabric sleeve according to the invention.
FIG. 2 is a diagrammatic cross section of a section of a tubular knitted fabric sleeve, under stress, spot-adhered to a barrier layer during the process of adhering these materials according to the embodiment of FIG. 1.
FIG. 3 corresponds to FIG. 2 and illustrates the element of FIG. 2 after relaxation of the stress on the tubular knitted fabric.
FIG. 4 is a diagrammatic cross section of a section of a tubular knitted fabric sleeve corresponding to FIG. 3 but having a section of tubular fabric thereover as outer fabric sleeve 47.
The present invention provides a novel orthopedic cast comprising an assembly of a tubular knitted fabric base sleeve, an inert liquidimpermeable protective intermediate performed plastic film barrier layer and a porous tubular knitted fabric outer sleeve which is receptive to a liquid resinous composition which can be set to a rigid condition to render said outer sleeve rigid and form the final cast.
The phrase liquid resinous composition is used herein to include compositions which are resinous or resin-forming. The former class includes resins capable of setting through catalysts, further polymerization or cross-linking after application to form the rigid set cast. The latter class comprises monomer systems including single monomers, mixtures of monomers and mixtures of monomers with polymers reactive therewith, which react after application to form the rigid set cast.
The fabric sleeves used according to the present invention may be of identical stretchable fabric, such as 108 needle tubular knitted cotton knit on a 4 inch diameter cylinder, commonly used in the manufacture of hosiery and underwear. The size or diameter of the tubular fabric may be varied depending upon the girth of the member being treated. The sleeve should fit snugly over the member without exerting undue pressure thereon. It should be a stretchable fabric which can be stretched and slipped over the arm, leg or body with relative ease and which will conform to the shape of the member when relaxed. Obviously different diameter sleeves are required for the arm, leg and chest, and for children, adults and animals. Similarly, fabrics other than knit cotton are suitable, including but not limited to those woven from yarns of nylon polyamide, rayon cellulose, acrylic fabrics such as polyacrylonitrile, and the like, and from blends of yarns of such materials. Acrylic fabrics are preferred for their non-allergenic properties, for their ability to retain resin coatings at their surface rather than unduly absorbing them, and for their wicking action which permits evaporation of moisture from the skin through the ends of the acrylic fibers. Fabrics from crimped filaments and yarns are quite stretchable and very suitable. Terry fabrics are preferred materials, particularly for the base sleeve, since the bulkiness of such fabrics allows for trauma associated with breaks and fractures. The uncut pile loops also provide excellent air circulation adjacent the skin and moisture absorption, and thereby reduce the chances of skin irritations resulting from prolonged wearing of the cast.
The inert, liquid-impermeable protective intermediate layer comprises a preformed film or sleeve of flexible plastic film which is either separate from the fabric sleeves or attached to one or both sleeves such as by means of an adhesive, by heatbonding means, and the like. If preattached, the tubular film must be of sufficient diameter that it does not interfere with the stretching of the fabric sleeves during application of the sleeves over the injured member. Also loose films of polyethylene, polypropylene, polyethylene terephthalate polyester, and the like, are suitable because they are inert to most resinous compositions and solvents contained therein. Heat-shrinkable films such as polyethylene films used for contour packaging are also very suitable because a relatively small amount of heat can cause such films to shrink to the contour of the injured member. Thicknesses of from 0.25 mil up to about 2 mil are preferred.
The prime function of the barrier film is to prevent the ingredients of the resinous composition from penetrating through to the skin of the wearer and causing possible dermatological irritation. The barrier layer also serves to concentrate the rigidifying resin in the top sleeve to produce a cast of uniform strength. Also, according to a preferred embodiment, the barrier layer is one which is highly reflective of infrared radiation and functions as a thermal barrier to protect the injured member against discomfort or harm which may be caused by the heat exotherm generated during the curing of the rigid resin-forming composition.
According to one embodiment of this invention, one coated fabric tube may fulfill the functions of both an inner and an outer sleeve and a barrier layer. The sleeve is cut so as to be double the length of the portion of the member to be treated. The sleeve is inverted over itself and pulled on over the first section to produce a double thickness with the barrier layers contacting each other prior to placement on the injured member. Then, after placement on the injured member, the rigidifying resin is formed in the top fabric sleeve to produce the rigid outer sleeve.
According to a preferred embodiment, the barrier layer is a preformed plastic film attached to the fabric sleeve as shown in FIG. 1. Since most plastic films have limited stretchability, the plastic film must be spot-laminated to the fabric sleeve in such a way that the necessary stretchability of the fabric sleeve is retained. This may be accomplished by stretching the fabric sleeve over a flat platen or rounded mandrel, applying spots or lines of adhesive thereto or to the plastic film, wrapping the film around the sleeve with the adhesive therebetween to spotattach the two, and withdrawing the laminate from the surface over which it is stretched.
The apparatus of FIG. 1 comprises a mandrel 40 and a heated roller 41 driven in reverse rotation thereto, as illustrated, for adhering the plastic film barrier layer to the fabric sleeve. The diameter of the mandrel corresponds to the diameter of the fabric sleeve 11 when the sleeve is stretched to the desired degree corresponding to the end use to which the final cast will be put, i.e. an arm, leg or chest cast.
The plastic film 44 is preferably a conventional metallized film such as vacuum-aluminized Mylar polyethylene terephthalate polyester film having a thickness of from about 0.5 mil to about 2 mils. The vacuum-deposited aluminum is a continuous layer of minute thickness which does not interfere with the weight or flexibility of the plastic film. However it provides a thermal barrier and affords substantial insulation to the treated member against heat generated during cure of the rigid resin-forming composition. Metal coatings other than aluminum may be used, or the barrier coating or film may be pigmented or otherwise inherently have heat-reflective properties.
The plastic film 44 may be joined to the fabric sleeve by applying to the surface of the plastic film a series ofspaced parallel stripes of heat-active adhesive which extend widthwise on the film illustrated in FIG. 1, i.e. perpendicular to the length of the film and parallel to the length of the fabric sleeve.
The adhesive may be any conventional heat-sensitive, heatactivatable composition. Such known compositions are printed onto the barrier film or, if desired, onto the fabric sleeve in the form of a solution of the adhesive composition as spaced applications such as spots or stripes having a width of about one-fourth inch and spaced by about three-fourths inch. After evaporation of the solvent, the spots are dry and nontacky to the touch but are activatable at temperatures above room temperature and below a temperature detrimental to the fabric sleeve. A preferred activation temperature range is from about 150 F to 250 F.
Referring specifically to FIG. 1, the fabric sleeve 11 is stretched and drawn over the mandrel 40 so that a substantially equal length of the sleeve remains off the mandrel. The mandrel 40 and the heated roller 41 are in close association, so that the fabric sleeve is slightly compressed therebetween, and are slowly counter-rotated as illustrated so as to draw and compress the barrier film 44 therebetween against the fabric sleeve. The barrier film carries heat-adhesive stripes on the underside thereof adjacent the fabric sleeve and parallel to the length of the fabric sleeve, and a vacuum-applied aluminum layer 45 on the opposite surface.
The heated roller has a surface temperature of about 200 F which is sufficient to tackify the adhesive stripes and bond the barrier film to the stretched fabric sleeve. A sufficient length of plastic film is used to completely cover the circumference of the fabric sleeve and slightly overlap itself. At this point the film is cut, the laminate is withdrawn from the mandrel, a new fabric sleeve is drawn over the mandrel and the process is repeated.
FIG. 2 illustrates the cross-section of the laminate comprising the barrier film 44 and the fabric sleeve 11 immediately prior to withdrawal from the mandrel and viewed along the length of the mandrel. The sections of the adhesive stripes 46 unite the underside of the film to the fabric at uniformly spaced intervals and the top surface of the film carries a heatrefiective layer 45.
FIG. 3 illustrates the laminate of FIG. 2 after withdrawal from the mandrel. The fabric sleeve 11 has contracted, causing the spacing between the adhesive stripes 46 to be reduced and causing the barrier film 44 to corrugate, as illustrated. Thus, the barrier film is corrugatedly attached to the sleeve by adhesive stripes 46.
The portion of the fabric sleeve 11 which is not laminated to the barrier film, as shown in FIG. 1, is inverted over the barrier film to provide the assembly having the resin-receptive outer fabric sleeve 47, as shown in FIG. 7, prior to application of the assembly to the injured member. This isolates the barrier film 44 between the inner fabric sleeve 11 and the outer fabric sleeve 47 and facilitates the application of the assembly.
The rigid outer sleeve 13 is produced after the assembly has been slipped over the injured member by uniformly wetting the receptive surface of the outer fabric sleeve, such as sleeve 47 of FIG. 4, with a liquid resinous composition capable of setting to a rigid structure on curing, and then curing the resinous composition. The resinous composition is preferably of the type which develops a relatively low exotherm during the curing or setting reaction, and which can be applied in aerosol form from a spray can. Preferred materials in this regard are the polyurethane-forming compositions such as those disclosed in US. Pat. No. 3,378,511 which comprise polyisocyanate, polyether polyol, plasticizer and an aliphatic alcohol. Such compositions begin to gel and cure to an opaque, hard, dense product in about 2 minutes and generate an acceptably low exotherm. Other rigid resin-forming compositions are also suitable including water-reducible polyesters, phenoxy resins, epichlorohydrin-bisphenol-A copolymers, polyester polyurethanes, and polyether urethanes in association with bifunctional cross-linking agents possessing reactive hydrogen groups such as diamines and dibasic acids. If desired, the resin-forming components may be applied separately, such as by impregnating the fabric sleeve with one or more of the resin-forming components and then applying a curing agent or crosslinking agent to set the resin.
Other systems are also suitable such as the use of polymers of styrene, methyl methacrylate or other unsaturated low polymers in association with bifunctional unsaturated monomers as cross-linking agents. Suitable monomers include allyl alcohol and divinyl benzene. Also, the unsaturated alkyd polyester resins are suitable in combination with styrene monomer or low polymer as crosslinking agent. Glyptal alkyds of maleic anhydride and ethylene glycol are preferred, in association with styrene.
The selection of any particular resin-forming system is a matter of choice to one skilled in the resin art in the light of the present disclosure. The important considerations are low exotherm, fast-setting action, convenience of form and acceptable toxicity.
The rigid resin-forming composition is preferably applied to the outer fabric sleeve in aerosol form using a codispensing valve which meters the required quantity of resin-forming ingredients from separate containers, mixes them in the valve and sprays the mixture onto the fabric sleeve.
The use of texturized acrylic knitted fabric sleeves offers an important advantage in that acrylic fabrics tend to repel liquid solutions and retain them on the surface while the texture of the fabric permits retention of sufficient resinous composition to produce the desired strength. The rigidifying resin preferably is applied as a uniform layer having a thickness of about 1 mil and is concentrated at the surface of the outer sleeve to permit quick setting. Substantially greater thicknesses, as caused by complete absorption of the resin solution into the outer sleeve, retard drying and setting and require longer curing periods.
In the instance of a broken or fractured arm, a piece of continuous tubular knit fabric is used measuring approximately 40 inches long. Half of this fabric is knitted terry cloth on the inside. This fabric is knit with 1/22 acrylic yarn under loose tension on a 4 inch 108 Needle Standard H knitting machine.
To apply the present cast, the open end of the assembly is gently pulled up over the am so that the other end of the latex coating or plastic film is at the lowest extremity of the area to be immobilized. Any excess tubing gathered on the upper part of the arm may be trimmed off a few inches above the upper extremity to be immobilized. Now the assembly is positioned.
The remaining section of tubular knitted fabric, the outer sleeve, is doubled over the coating or plastic film and is also gently pulled up over the barrier layer until the crease at the lowest extremity meets the terry fabric under the latex coating. Again any excess tubing gathered on the upper part of the arm may be trimmed off to coincide with the end of the base sleeve. Now both the base sleeve and the outer sleeve are positioned.
The exposed surface of the outer sleeve is receptive to a resinous coating. Any minor adjustments are made on the sleeves and final positioning of the broken or fractured arm is made. This being completed, the fabric is sprayed with the resin, ideally to a thickness of 1 mil. Care is taken not to overspray on the exposed skin. It is desirable to end the spray application about 1 inch from either end. This area may be masked out. The physician may find it also desirable to cover the exposed skin with a towel, plastic film or protective cream as an added precaution. Further care should be taken to avoid open flame near the application as resin compositions, particularly those containing volatile solvents, are flammable. The resin composition preferably is pigmented to create a flesh-tone coloration.
The fabric having been completely sprayed, the resin composition begins to react. The solvent, if present, begins to be released by evaporation. The cooling effect of the evaporation of such solvents is useful in offsetting much of the exothermic heat generated during curing of the resin composition. Also a thermal barrier layer is preferably used where the exotherm is high. The cure of the resin composition provides a hard, tough, rigid coating within from less than 1 minute up to about 8 minutes. The set-up time can be reduced in most cases by the application of heat from an infrared lamp.
The cast, now complete, measures between one-eighth inch to one-fourth inch thick. It is inconspicuously colored fleshtone, very light and impervious to water, permitting the patient to bathe with much more case than with the conventional plaster cast. The cast is easily removed with a pair of heavy bandage shears.
The present casts may be provided with windows or openings which are occasionally necessary in connection with fractures which pierce the skin. To provide such a window, the cast is applied in normal manner except that a piece of resin-impervious material, such as adhesive tape or plastic film, which corresponds to the size of the desired window is applied to the desired location of the outer sleeve prior to the application of the rigidifying resin to the outer sleeve. Then the impervious material is removed and the protected underlying areas of the sleeves and barrier layer are cut out with a scissors to provide a window to the desired section of the injured member.
The present casts may also be provided with additional support where the cast is to be subjected to heavy stress, such as in the case of a foot cast which must support the weight of the body. In such cases, the cast is applied in the manner described herein. The rigidifying resin is applied and then a narrow strip of fiberglass tape is applied over the resin while the latter is still tacky. After the resin has set, more resin is applied over the fiberglass tape and when the additional resin has set, the reinforced cast will support the weight of the body with ease. For a foot and ankle cast, a 2 inch wide fiberglass tape may be applied over the cast down the back of the leg, over the heel and under the foot. A button" may be provided on the fiberglass tape beneath the heel, if desired, to provide a contact element with the floor, as is conventional with foot and leg casts.
Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.
1. Process for applying an orthopedic cast to an injured member which comprises the steps of:
1. providing a stretchable tubular sleeve assembly comprising (a) a stretchable tubular knitted fabric base sleeve having a wicking action with respect to moisture and which is adapted to conform itself to the shape of the injured member, (b) a tubular flexible barrier layer over said base sleeve comprising a preformed plastic film having a circumference which is greater than the circumference of said tubular base sleeve and which is sufficiently large to permit stretching of said base sleeve, and (c) a stretchable tubular knitted fabric top sleeve of stretchable tubular fabric over said barrier layer which is also adapted to conform itself to the shape of the injured member;
2. stretching said tubular sleeve assembly over an injured member and allowing it to conform to the shape of the injured member;
3. applying a substantially uniform liquid layer of rigidresin-forming composition to the surface of said top sleeve of said assembly, said barrier layer preventing migration of said liquid layer to the base sleeve; and
4. curing said liquid layer to form a rigid resinous layer at the surface of said top sleeve to provide said orthopedic cast.
2. Process according to claim 1 in which said base sleeve and said top sleeve comprise a'unitary length of sleeve which is folded over itself to confine the barrier layer therebetween.
3. Process according to claim 1 in which said barrier layer is a preformed tubular plastic film which has a substantially greater diameter than said sleeves and is spot-attached to one of said sleeves to permit substantial stretching of said sleeves.
4. Process according to claim 1 in which said barrier layer is highly reflective of heat and functions as a thermal barrier.
5. Process according to claim 1 in which said rigid-resinforming composition comprises a polyurethane resin-forming composition.
6. Process according to claim 1 in which said base sleeve comprises a knitted terry acrylic fabric.
7. Process for producing a stretchable tubular sleeve as sembly adapted to be applied to an injured member for forming an orthopedic cast thereon comprising:
a. providing a tubular base sleeve of stretchable tubular knitted fabric which has a wicking action with respect to moisture and which is adapted to conform to the shape of an injured member;
b. stretching said base sleeve and applying thereover a tubular flexible barrier layer comprising a preformed plastic film which overlies said base sleeve to prevent penetration of a liquid therethrough to the base sleeve and which has a circumference approximating the stretched circumference of said base sleeve; and
c. stretching over said barrier layer a stretchable tubular knitted fabric top sleeve which is also adapted to conform to the shape of the injured member and which overlies said barrier layer and confines said layer between itself and the base sleeve, said plastic film barrier is spot-attached to one of said sleeves while said sleeve is stretched, relaxation of said tubular sleeve leaving said film corrugatedly attached thereto and said assembly being adapted to be stretched over an injured member and said top sleeve being adapted to receive a liquid layer of rigid-resin-forming composition which is prevented from penetrating to said base sleeve by said barrier layer.
8. Process according to claim 7 in which said plastic film barrier layer is spot-attached to said base sleeve while said sleeve is stretched, relaxation of said tubular sleeve leaving said film corrugatedly-attached thereto.
9. Process according to claim 7 in which said tubular base sleeve and said tubular top sleeve comprise a continuous length of tubular knitted fabric material, the barrier layer being applied over a length thereof forming the base sleeve and a remaining length thereof being inverted over said base layer to form said top sleeve.
10. Process according to claim 7 in which said base sleeve comprises knitted terry acrylic fabric.
11. Process according to claim 7 in which said barrier layer is heat-reflective.
12. A stretchable tubular sleeve assembly produced according to the process of claim 7.
13. A stretchable tubular sleeve assembly produced according to the process of claim 8.
14. A stretchable tubular sleeve assembly produced according to the process of claim 9.
15. A stretchable tubular sleeve assembly produced according to the process of claim 10.
16. A stretchable tubular sleeve assembly produced according to the process of claim 11.