Patent ID: 12213901

DETAILED DESCRIPTION

Referring now toFIGS.1through7generally, and to the implementation shown inFIGS.1-3in particular, a cast21of the present disclosure is adapted for use on a lower extremity to be treated. The use of cast21and other cast implementations and variations encompassed by this disclosure may be used As explained herein, cast21may be applied as shown to lower extremity a without requiring water activation. One set of applications for cast21involves treatment of lower extremities of diabetics suffering from wounds, amputations, ulcers, and other surgeries or treatments related to the foot. Such conditions may require not only isolation and healing of wounds and injuries facilitated by casts, but potentially immobilization or limited ankle movement, off-loading of forces from heel or injured areas, such as during the gait cycle, and distribution of weight (“weight bearing”) during standing and other activities. Treatment of still other lower extremity conditions benefitting from stabilization of the foot or ankle joint relative to the leg are likewise contemplated. For the sake of clarity, the use of casts disclosed herein, and their association with “treatment” or a lower extremity “to be treated,” encompasses the full range of medical conditions, whether the person is wounded, injured, or at-risk of developing a wound, injury or other medical condition, and whether such condition is dermatologic, orthopedic, neurological, biomechanical, or surgical, whether for diabetics or other persons.

In the illustrated implementation, as seen inFIG.3, cast21may assume a first, pre-application configuration23, shown as a cast blank21′, in which sheet-like material25has dimensions to circumferentially enclose the lower extremity to be treated.

In order for material25to enclose a variety of sizes of lower extremities, it will be appreciated that the surface area of sheet-like material25may be chosen to give some slack or extra room in terms of applicable dimensions. Lower extremities may also be carrying bandaging or other surface treatments which thus may increase the circumferential size of lower extremities to be received within cast21and the volume defined by sheet-like material25.

In this implementation, sheet-like material25terminates in an upper end27to be located on a patient's leg in a manner consistent with a lower-extremity cast of any suitable length that is distal to the knee and proximal to the ankle, and a lower end29to be located on the patient's foot. More particularly, cast21includes a pair of cut-outs28located relative to ends27,29so as to expose heel b and optionally ankle c when lower extremity a is enclosed therein. The distance between upper end27and lower end29is also selected so that, when cut-outs28are suitably positioned about heel b/ankle c, lower end29terminates anterior to the ankle b and posterior to toes d. Cast21, as illustrated inFIGS.1-4, is an open-toe, open-heel cast.

In another implementation, seen inFIG.4, sheet-like material25is of sufficient stiffness to be formed into another pre-application configuration24in the form of a hollow cylinder31which defines a volume26into which the lower extremity is receivable. Hollow cylinder31includes a cylindrical wall33and a longitudinally extending slit35formed in cylindrical wall33and extending between upper and lower ends27,29of cast21. As such, slit35defines opposing edges37.

In the illustrated implementation, sheet-like material25comprises at least a first layer39and a second layer41(FIG.2) of the sheet-like material25, the layers39,41having a pre-determined combined flexibility selected so that the layers are manually transformable from a, pre-application configuration, such as shown at23(FIG.3),24(FIG.4) to a second, post-application configuration40(FIG.1) in contact with the lower extremity when received therein.

Sheet-like material25and its at least two layers39,41have a predetermined combined flexibility, in particular, so that side edges38of cast blank21′ may be manually displaced in the directions indicted by arrows A, generally orthogonally to the plane of blank21′. By such displacement, opposite side edges38are brought adjacent to or overlapping each other as they are applied around the circumference of the lower calf and foot to form post-configuration40shown inFIG.1. Furthermore, the pre-determined flexibility of sheet-like material25and its two layers39,41is selected so that, when in pre-application configuration24, opposing edges37of cylindrical wall33may be manually parted or separated from each other at slit35by a sufficient amount so that cylinder31may be positioned around the lower extremity by receiving the lower extremity into the expanded slit35. Thereafter, by manually urging opposing edges37toward each other, volume26enclosed by cylindrical wall33is lessened and inner surfaces43of the cylindrical wall33are brought into substantial contact with the lower extremity received therein.

In one possible implementation, cast21and all of its layers consist essentially of material that is non-water-activatable. More generally, cast21is formed to consist essentially of material which enables the end-user or medical professional to apply cast21to a lower extremity by manipulation of material25itself, without need for water or other curative agents, and without the need to add additional time for setting of the casting material, as in the case of plaster and other comparable materials.

As such, the first layer39may comprise an inner layer comprising a water-resistant or waterproof flexible material, optionally including some cushioning material and some breathability characteristics, such inner layer in substantial contact with the lower extremity and having inner surface43in contact (direct or indirect) with such lower extremity. Second layer41is disposed to the outside of first layer39, directly or indirectly overlying first layer39. In certain implementations, outer, second layer41may consist essentially of bands of semi-rigid, non-water-activated polymeric material, such as vinyl, arranged in a suitable weave pattern, such as a pattern to form a spica. The spica would comprise a series of intersections and at least one opening, such opening being locatable at the heel of the extremity when received therein and at least one of the intersections of the spica being advantageously positioned at one or more points on the ankle joint of the lower extremity. Second layer41may comprise one or more materials selected from the group consisting of vinyl, elastic, PVC, paper, rubber, plastic, polyethylene, and other polymeric materials, flexible metal, wood fibers and pulp-based derivatives, flexible ceramic components, nylon, knitted or technical fabrics, tapes, including bands of any of the foregoing, elasticized plaster, pre-formed fiberglass, and alginate.

Layers39,41may be suitably adhered to each other, fused, sputtered, flocked, or otherwise processed to form a two-layer composite and thus substantially resemble a single layer. Such fusion and integration of the characteristics identified above for layers39,41is within the scope and definition of the two layers when referred to herein and within the scope of this disclosure. Suitable adhesive may likewise be used between opposing surfaces of adjacent layers, or as a separate adhesive layer. In addition, layer39may have its inner surface equipped with fugitive or other adhesive having a tack appropriate for contact with the skin and removal therefrom without inappropriate discomfort, such tack likewise being sufficient to assist in maintaining inner surface43in substantial contact with underlying portions of the lower extremity received in cast21.

Similarly, a third, intermediate layer45may be interposed between inner layer39and outer layer41, such intermediate layer45providing any number of desirable properties, whether adding to the composite flexibility or stiffness of overall cast21, providing padding, or providing wicking, water-resistant or waterproof characteristics. In one variation, cast21comprises three layers39,45,41wherein the inner layer39is a water-resistant, breathable material, such as GORTEX, intermediate layer45is of material serving primarily a padding function, and outer layer41is vinyl or other polymeric material, with the majority of flexibility or stiffness being provided by such outer layer41. For this three-layer implementation, the average thickness may range (in millimeters (“mm”)) from 15 mm to 35 mm, generally, and from 9.5 mm to 15 mm for applications where less weight-bearing or off-loading is needed. Outer layer41may comprise two layers of vinyl bands, each layer having respective thickness of 0.4 to 0.5 mm, so that layer41has a thickness of 0.8 to 1.0 mm, or one such vinyl layer may be used in other applications. An outer layer41of semi-rigid polymeric material ranging from 0.4 to 4.0 mm has been found suitable for many treatment protocols, including those associated with diabetic injuries, wounds, or at-risk conditions, but also encompassing non-diabetic conditions.

Further variations and dispositions of multiple layers of sheet-like material25are likewise within the scope of the current disclosure. Likewise, the overall or average thicknesses of cast21or other implementations within the scope of this disclosure may be below or above the ranges stated for the above-described implementation, so long as the semi-rigidity of the resulting sheet material25permits manipulation from a pre-application configuration to a post-application configuration around the extremity, in which the therapeutically desired immobilization or weight-bearing is achieved.

When a layer of cast21is described herein as being in “contact” with, or “overlying” the lower extremity, unless the context indicates otherwise, such description includes both direct and indirect contact, such that the layer operates as intended. Thus, for example, the foregoing three layers39,45,41are each in “contact” with opposing portions of lower extremity a, as each imparts its characteristics thereto, including one or more of water-resistance, padding/protection, and immobilization.

Similarly, it will be appreciated that other intersecting weave patterns besides a spica are suitable for either outer layer41or first layer39, as are any number of overlapping configurations of tape, bands of material, and the like. Second layer41and its polymeric material, as well as layers39,45may also be in a non-weave pattern or not formed of bands, but rather be formed of a substantially uniform, composite, woven or formed material.

Whatever the weave, pattern, uniformity, composition, layering, or other physical characteristics of sheet material25, the resultant cast21is formed with a combined, pre-determined flexibility not only to remain in substantial contact with the underlying lower extremity a, but also to substantially control movement of ankle c, especially relative to leg f, within a therapeutically desired range, to off-load forces away from heel b or other pressure points, and to bear sufficient weight, based on therapeutic needs. The appropriate, therapeutically selected range will vary depending on the lower extremity condition being treated.

For certain lower extremity conditions, the foregoing therapeutic goals or a desired amount of pain relief may be accomplished by having the mechanical properties of resultant cast21include sufficient rigidity or stability of material25so that cast21substantially remains in its post-application configuration40except for a therapeutically acceptable range of movement of ankle c (or other lower extremity anatomy) during walking, standing, and other anticipated activity involving the lower extremity. In certain cases, the rigidity or stability of cast21achieves immobilization, pressure relief, off-loading, and the other desired therapeutic or pain-relief goals without requiring a separate splint, CAM walker, boot, brace, or other lower-extremity orthosis appropriate to treat the injured lower extremity to hold material25in position.

In other cases, cast21has a combined flexibility pre-determined to achieve a level of immobilization by resisting movement about ankle c and maintain post-application configuration40during most anticipated activities, while using cast21in combination with a splint, CAM walker, boot, brace, or other lower-extremity orthosis appropriate to treat the injured lower extremity to provide pressure relief or off-loading to the lower extremity being immobilized by the rigidity of cast21. So if cast21has been fitted to lower extremity a in the neutral position shown inFIG.1, in which foot e forms an angle β of about 90° with leg f, the pre-determined flexibility of cast21restricts motion of ankle c (and related anatomy of lower extremity a) to a therapeutically acceptable range during a therapeutically determined percentage of anticipated patient activity. Among the orthopedic motions of potential therapeutic interest to limit by means of cast21would be the degrees of plantar flexion γ and dorsiflexion θ.

As seen inFIG.14, in a version of cast21used with a lower-extremity orthosis, such as a CAM walker419, while a certain amount of weight-bearing and off-loading may be accomplished by cast21, additional weight-bearing and off-loading may be accomplished by CAM walker419.

While the mechanical properties of sheet-like material25, cast21and other aspects of this disclosure are described using the term “flexibility,” mechanical properties of cast21and its material25may be expressed using complementary and related mechanical properties of cast21and its material25, such as the complement of flexibility, namely rigidity, stiffness or resiliency. Flexibility and stiffness may be determined and expressed as a function of one or more degrees of freedom, and in terms of moments of force. As such, flexibility and rigidity of portions of material25of cast21, whether located at, or proximal, distal, lateral or medial of the ankle joint, may be characterized in terms of resistance to dorsal, plantar, lateral, or medial flexion at the ankle joint, as well as eversion or inversion of the foot.

Similarly, rigidity of the portions of cast21located on plantar surface161(Fig. of the foot may be expressed in terms not only of rigidity, but also in terms of their capacity to off-load a force at one plantar location to another, such as from the heel toward the mid-foot, or to bear or distribute weight so as to relieve pain points on the foot. Otherwise stated, flexibility and rigidity may be in relation to moments of force, compressive forces, tensile forces, shear forces, tangential, orthogonal, or other force vectors, or resistance to such forces. Flexibility and rigidity as applied to sheet material25and cast21may be designed, determined, or selected by reference to established ASTM or ISO standards associated with casts or lower-extremity orthoses. As such, the biomechanical properties of cast21and sheet-like material25are likewise quantifiable using the same metrics currently used for evaluating properties and performance of current casts, immobilizing devices, boots, or braces, such as CAM walkers, or other lower-extremity orthoses appropriate to treat the lower extremity.

In a further variation of this disclosure, there may be a plurality of casts21, each having an associated, pre-determined flexibility associated therewith, so that a practitioner may select an appropriate one of the casts21, and form it from its pre-application configurations23,24to its second, post-application configuration40, and thus have associated therewith the pre-determined flexibility of material25for the therapeutically desired range of motion for the condition being treated.

In still further implementations, it will be appreciated that the pre-determined, combined flexibility for a given portion of cast21may vary depending on its location on blank21′ or cylindrical wall33relative to ends27,29. Thus, for example, those portions of sheet-like material25likely to be subjected to increased bending moments or other forces during walking or other activity of the lower extremity, such as plantar impact surface61(FIG.1) may be designed to have increased rigidity (less flexibility) at or adjacent to such regions to maintain the substantial contact, the therapeutically desired range of ankle movement, or the other desired therapeutic benefits to cast21.

Second layer41, or the combined flexibility of sheet material25, may be selected so that cast21is suitable for bearing weight or distributing downward force of the user, such as when standing. With reference to the kinetics of the gait cycle, the flexibility (or its complementary property of rigidity) may be such as to offload a therapeutically significant percentage of force forward of the heel, or to bear weight or distribute force of the user during heel strike, toe-off, propulsive, or other phases of the gait cycle. The flexibility and rigidity of cast21may be selected to control ankle movement during the gait cycle at levels comparable to those of a water-activated cast or to those of a CAM walker or any number of boots, braces, or other lower-extremity orthoses appropriate to treat the lower extremity, and may likewise bear/transfer weight, thereby eliminating the need to use such braces and boots. Again, though cast21may permit a lower extremity received therein to become weight-bearing and otherwise not require additional bracing or support structure, this disclosure is not so limited, and the cast21herein may be used in conjunction with other orthoses, such as a CAM walker, boot, brace, or other lower-extremity orthosis appropriate to treat the lower extremity.

Cast21may be implemented to include another layer, either adhered or otherwise fused to inner surface43of inner layer39or manually separable therefrom, forming a lining or sock (not shown). In one suitable implementation, this lining or sock comprises knitted or non-woven technical fabric or fabrics, the fabric configured to have properties which benefit treatment of the lower extremity received therein. The lining or sock may be in direct contact with the lower extremity, such that overlying inner layer39(and outer layer41) are in indirect contact with such lower extremity. The lining or sock may have anti-microbial properties, insulative properties, wicking properties, or anti-friction properties, or any combination of the foregoing.

As such, in one implementation, not only does cast21consist essentially of material that is non-water-activatable, but also such cast comprises the following layers of sheet-like material, whether separable or fused together, the four layers circumferentially enclosing and disposed relative to the lower extremity, from innermost to outermost as follows: a lining or sock, layer39of water-resistant/waterproof material layer45of padded material, and semi-rigid layer41.

Variations to pre-application configuration23are contemplated by this disclosure, such that material25need not be in the planar form of blank21′ or cylindrical form31, may not require slit35, and may not be pre-formed. For example, the cast layers39,41may be tightly rolled when in their pre-application configuration. Pre-application configurations may likewise include more than one piece, such as one flat or cylindrical piece for the leg and one for the foot, such multiple pieces having portions designed for overlapping at the ankle. Still other pre-application configurations are possible.

In still other implementations, referring more particularly toFIGS.5-7, cast121and its corresponding blank121′ may have sheet material25(with a variety of functional layers as described with reference toFIGS.1-4, especiallyFIG.2. Sheet material25is arranged so as to include one or more tabs151, may exclude the cut outs28shown in the embodiment ofFIGS.1-4, and may include a foldable section153which can be disposed anteriorly around the toes. As such, sheet material25may assume a pre-application configuration134corresponding to blank121′ and a post-application configuration140, corresponding to the closed toe, closed heel arrangement shown. Two apertures159are suitably sized and located on blank121′ to potentially receive all or part of the malleoli of ankle c therein when cast121has been transformed into its post-application configuration140engaging lower extremity a, with the goal of improving fit or comfort. Similarly opposite sides138have been provided with detents157to potentially become located above the heel proximate to the Achilles tendon when in its post-application configuration140with the goal of improving fit or comfort. As such, cast121and its corresponding blank121′ form a closed heel, closed toe configuration as shown inFIGS.6and7.

Still further implementations of this disclosure may enclose or expose heel, toe and other portions of lower extremity a to effectuate desired treatments. As such, referring toFIGS.8-10, a closed-heel, open-toe cast221(and corresponding blank221′) includes sheet-like material225having the functional layers discussed previously, such as inner and outer layers39,41(FIG.2), and upper and lower ends227,229sized and located similarly to upper and lower ends27,29ofFIG.3, with opposite, longitudinal side edges238, and apertures259and detents257similar to apertures159and detents157ofFIGS.5-7. Blank221′ may be manipulated from a substantially planar pre-application configuration223, such as by moving opposite side edges238generally orthogonally to the plane ofFIG.8as indicated by arrows A, and sheet material225has a preselected semi-rigidity to hold its post-application configuration240shown inFIGS.9and10. As a result, blank221′ encloses heel b, yet leaves toes d open. A self-sticking surface treatment portion230may be provided, here extending longitudinally along one of the side edges238, to assist in avoiding peel back of corresponding side edge238when in post-application configuration240(FIGS.10,11).

Referring toFIGS.11-13, an open-heel, closed-toe cast321(and corresponding blank321′) includes upper and lower ends327,329sized and located as discussed with reference to the previous implementations, including cut-outs328to generate an opening about heel b but toe portion353is manually moveable to enclose toes d, as shown. Blank321′ is composed of sheet material25(like reference numbers throughout this disclosure referring to like elements in previously described implementations). Similarly, variations on previously described features have been given corresponding reference numbers with respect to cast321, including cut-out portions328to expose the heel when received therein, tabs351, and side edges338. As previously described, blank321′ may be manipulated into a post-application configuration340(FIGS.12-13) from pre-application configuration323(FIG.11).

An orthosis419incorporating features of the casts described herein is shown inFIG.14. Orthosis419in this implementation comprises a CAM walker with a rigid frame430and cast421. Rigid frame430has an inner surface432forming a volume suitable for receiving cast421therein. Cast421has features and structures as described with reference to the previous implementations of casts21,121,221, or321, including sheet material25as described herein. Cast421has been manipulated into its post application configuration440around lower extremity a. Cast421has a corresponding blank as described previously for the other implementations, formed of semi-rigid material with suitable flexibility/rigidity described above. Cast421has a plantar portion434and a leg portion436, the portions having respective outer surfaces438. Inner surface432of rigid frame430engages at least one of the outer surfaces438of the cast421.

In one possible variation, cast421is formed of at least two layers of sheet-like material, with the layers having a predetermined, combined flexibility selected to have the layers manually transformable from a first, pre-application configuration in the form of the blank with side edges, such as blanks21′,121′,221′, and321′ previously discussed, before fitting on the lower extremity, to the second, post-application configuration440after the fitting on the lower extremity.

As in previous implementations, post-application configuration440is formed in response to manual force applied to the blank to bring side edges of the blank relatively toward each other to define a volume into which the lower extremity is received and to define an inner surface to substantially contact opposing portions of the lower extremity when received therein. The predetermined flexibility is selected so that cast421, separate and apart from frame430, limits at least one of plantar flexion, dorsiflexion, eversion, and inversion of the ankle of the lower extremity by at least 50% compared to a corresponding, non-casted movement of said ankle.

Rigid frame430may include a plantar support member450and a leg bracing member545. Plantar support member450is sized so that it may receive thereon the plantar portion434of the cast, and the leg bracing member545is configured to engage the leg portion436of cast421.

Testing was performed for one of cast implementations set out herein (without the related rigid orthosis), in which inner layer39comprises water-resistant material, layer45comprises padding, and outer layer41comprises two, 0.43 mm-thick layers of vinyl bands in a woven pattern forming a spica. It was found that the foregoing combination of non-water activated materials formed a combined flexibility to achieve desired therapeutic goals after application to a lower extremity. For example, measurements were taken of the range of motion of the ankle joint, subtalar joint, metatarsophalangeal joints, and gait analysis—all in relation to the motions of dorsiflexion, flexion, plantar flexion and inversion/eversion. The above-described testing was performed on a lower extremity having a base-line, non-casted range of motion. For the ankle joint, results/testing showed dorsiflexion limited to 90% compared to the non-casted range of motion, plantar flexion limited to 95% of the otherwise non-casted range of motion and ankle joint inversion/eversion limited to 95% compared to a non-casted range of motion. For the subtalar joint, motions were limited by more than 90% compared to non-casted. With regard to the metatarsophalangeal joints, plantar flexion was limited to 90%, while dorsiflexion was limited to 80%, the foregoing again compared to the base-line non-cast-range of motion.

With regard to the gait analysis, stride length was shortened by application of cast21, speed of floor propulsion decreased. No true heel strike was witnessed, thereby achieving off-loading. Steppage gait occurred with contact made with substantially all of the plantar surface of the foot from the metatarsophalangeal joints proximal to the heel. Rigidity and/or flexibility of cast21was such as to substantially limit the range of motion at the ankle and achieve slight, circumductive gait, with subjects reporting transmission of pressure/force otherwise felt at the foot up the leg to the tibia and calf area.

Operation and use of the cast21is apparent from the foregoing description. A patient, medical practitioner or other third party, by manual force, is able to transform the pre-application configuration of sheet-like material25,134and its multiple layers39,41, to a post-application configuration40,140around the lower extremity to be treated as shown inFIGS.1, and6-7, respectively. The resultant cast21exhibits mechanical properties of flexibility/rigidity selected to provide control of ankle movement or substantial immobilization, weight-bearing, offloading of pressure, a therapeutic environment, and other therapeutic benefits during the biomechanics of walking or other activity.

Cast21may be used as part of a computer-implemented system to diagnose, analyze, or otherwise evaluate performance of cast21itself, as well as any associated CAM walker, boot, brace, or other lower-extremity orthosis associated with the lower extremity under treatment. Data may be gathered by associating cast21with sensors capable of obtaining inputs on force, pressure, temperature, acceleration and the like, when cast21is being worn on the lower extremity a. In one possible implementation, such sensors are deployed at suitable, corresponding locations on inner surface43of cast21, such as on the portion of the inner surface opposing the plantar surface of the lower extremity received therein. Data thus gathered may be used as inputs to modify the rigidity or other parameters of cast21, or to design or modify the design of cast21or of orthoses associated with the lower extremity treatment, as set out in U.S. Pat. No. 9,201,413, the contents of which are incorporated herein by reference.

The foregoing is provided for purposes of illustrating, explaining, and describing implementations of this disclosure. Thus, although specific arrangements have been illustrated and described herein, other arrangements may achieve the same or similar purposed and may be substituted for the specific arrangement shown. Combinations of the above arrangements, and other arrangements not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. Therefore, it is intended that the disclosure not be limited to the particular arrangement(s) disclosed herein, and that such alternatives and equivalents are within the spirit and scope of this disclosure, as defined in the following claims.