WO2019243171A1 - Foot loading monitoring apparatus - Google Patents

Abstract

Embodiments of a loading of a body part, such as the foot, are disclosed. In some embodiments, an apparatus for monitoring load bearing of a foot, the apparatus includes a housing formed from a substantially flexible and conformable material, the housing sized and configured to be attached to the foot, the housing defining an interior volume, a sensor positioned in the interior volume, the sensor configured to provide data associated with strain on the housing as a result of loading of the foot, and a controller positioned in the interior volume, the controller configured to, based on the data associated with the strain on the housing produced by the sensor, determine and provide indication that the foot is loaded. The housing can be at least partially encapsulated in a conformal coating configured to provide cushioning when the housing is attached to the foot.

Description

FOOT LOADING MONITORING APPARATUS

Field

Embodiments of the present disclosure relate to apparatuses, systems, and methods for the monitoring of body loading, which can be applicable for monitoring or treatment of pressure ulcers.

Description of the Related Art

Pressure ulcers, which are also known as pressure sores, bedsores, or decubitus ulcers, are injuries to skin and underlying tissue resulting from prolonged pressure on the skin, soft tissue, muscle, or bone above capillary filling pressure (approximately 32 mmHg).

One type of pressure ulcer that develops on a foot is known as a diabetic foot ulcer (DFU), which tends to occur with higher frequency and intensity in the diabetic population. Management and treatment of diabetic foot ulcers requires offloading the wound by using cushioned footwear, such as a support boot, cast, shoe, etc. While offloading can be effective, because many offloading devices are removable, it has been found that patient non-compliance with the offloading devices plays a large role in the delayed healing of diabetic foot ulcers.

However, prior art approaches and systems provide no or little information regarding patients’ lifestyle and non-compliance or compliance with the offloading devices and support surfaces. Gaining insight into patients’ lifestyle can be important for prevention and healing of pressure ulcers. However, because of these limitations, prevention and healing of patients’ pressure ulcers using prior art approaches and systems may be delayed or, worse yet, the condition could worsen leading to prolonged discomfort, hospitalization, or even surgery.

SUMMARY

An apparatus for monitoring load bearing of a body part, such as a foot, can include a housing formed from a substantially flexible and conformable material. The housing can be sized and configured to be attached to the foot. The housing can have an interior volume. The apparatus can further comprise a sensor positioned in the interior volume. The sensor can be configured to provide data associated with strain on the housing as a result of loading of the foot. The apparatus can further comprise a controller positioned in the interior volume. The controller can be configured to, based on the data associated with the strain on the housing produced by the sensor, determine and provide indication that the foot is loaded. The apparatus can further comprise a housing that can be at least partially encapsulated in a conformal coating configured to provide cushioning when the housing is attached to the foot.

The apparatus of the preceding paragraph or any of the apparatuses disclosed herein can include one or more of the following features. The sensor can be a strain gauge. The strain gauge can be folded in half. The sensor can be attached to the housing. The controller can be configured to determine that the foot is loaded based on comparing the data associated with the strain on the housing to a loading threshold. The controller can be further configured to, based on the data associated with the strain on the housing produced by the sensor, determine and provide indication that the foot is unloaded. The controller can be further configured to determine a duration of time during which the foot is loaded based on determining a difference between a first time during which the foot is determined to have been loaded and a second time during which the foot is determined to have been unloaded. The controller can be further configured to calibrate the sensor. One or more of the controller or sensor can be positioned on a circuit board. The apparatus can further comprise a cushioning positioned over at least a portion of the circuit board. The apparatus can further comprise a portion of the circuit board with a region of substantially non- stretchable material. The conformal coating can be substantially stretchable.

An apparatus for monitoring load bearing of a body part can include a sensor configured to be attached to the body part and to provide data associated with strain on the sensor as a result of loading of the body part. The apparatus can include a circuit board with a controller, the controller configured to, based on the data associated with the strain produced by the sensor, determine and provide indication that the body part is loaded. The circuit board can be at least partially encapsulated in a conformal coating configured to provide cushioning when apparatus is attached to the body part.

The apparatus of any of the preceding paragraphs or any of the apparatuses disclosed herein can include one or more of the following features. The apparatus can include a housing enclosing the circuit board. The housing can enclose the circuit board but not the sensor. The sensor can be attached to the circuit board. The sensor can be adhered to the circuit board. The sensor can be adhered to the circuit board with substantially non- stretchable coating. The sensor can be substantially flexible. The sensor can be stretched, folded, or rolled up.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present disclosure will be apparent from the following detailed description, taken in conjunction with the accompanying drawings of which:

Figure 1 illustrates pressure ulcers including to diabetic foot ulcers according to the prior art.

Figure 2 shows a load- measuring apparatus according to some embodiments.

Figure 3 shows electronics of the apparatus of Figure 2.

Figures 4A and 4B show an encapsulated load- measuring apparatus according to some embodiments.

Figure 5 shows graphs of monitored load according to some embodiments.

DETAIFED DESCRIPTION

Introduction to Wound Monitoring and Therapy

Embodiments disclosed herein relate to apparatuses, systems, and methods for the monitoring of body loading and body position for treatment of pressure ulcers. Foading can refer to transferring or placing at least a threshold amount of force on a body part. Placing such threshold amount of force on the body part causes the body part to support weight. For example, loading of a foot can refer to transferring or placing at least a portion of the body weight (or body weight in combination with external weight) on the foot such that the foot is supporting at least such portion of the body weight. At least such portion of the body weight can serve as a threshold for determining that the foot has been loaded.

Some of the disclosed implementations can be utilized with a dressing (also sometimes referred to as wound dressing) alone or in combination with negative or reduced pressure. The apparatuses and components including an overlay and packing materials or internal layers, if any, are sometimes collectively referred to herein as dressings.

Some embodiments disclosed herein relate to wound monitoring or therapy for a human or animal body. Therefore, any reference to a wound herein can refer to a wound on a human or animal body, and any reference to a body herein can refer to a human or animal body. The disclosed technology embodiments may relate to preventing or minimizing damage to physiological tissue or living tissue, or to the treatment of damaged tissue (for example, a wound as described herein).

As used herein the expression“wound” may include an injury to living tissue may be caused by a cut, blow, or other impact, typically one in which the skin is cut or broken. A wound may be a chronic or acute injury. Acute wounds occur as a result of surgery or trauma. They move through the stages of healing within a predicted timeframe. Chronic wounds typically begin as acute wounds. The acute wound can become a chronic wound when it does not follow the healing stages resulting in a lengthened recovery. It is believed that the transition from acute to chronic wound can be due to a patient being immuno-compromised.

Chronic wounds may include for example: venous ulcers (such as those that occur in the legs), which account for the majority of chronic wounds and mostly affect the elderly, diabetic ulcers (for example, foot or ankle ulcers), peripheral arterial disease, pressure ulcers, or epidermolysis bullosa (EB).

Examples of other wounds include, but are not limited to, abdominal wounds or other large or incisional wounds, either as a result of surgery, trauma, sterniotomies, fasciotomies, or other conditions, dehisced wounds, acute wounds, chronic wounds, subacute and dehisced wounds, traumatic wounds, flaps and skin grafts, lacerations, abrasions, contusions, bums, diabetic ulcers, pressure ulcers, stoma, surgical wounds, trauma and venous ulcers or the like.

Wounds may also include a deep tissue injury. Deep tissue injury is a term proposed by the National Pressure ETlcer Advisory Panel (NPUAP) to describe a unique form of pressure ulcers. These ulcers have been described by clinicians for many years with terms such as purple pressure ulcers, ulcers that are likely to deteriorate and bruises on bony prominences.

Wound may also include tissue at risk of becoming a wound as discussed herein. For example, tissue at risk may include tissue over a bony protuberance (at risk of deep tissue injury/insult) or pre-surgical tissue (for example, knee tissue) that may have the potential to be cut (for example, for joint replacement/surgical alteration/reconstruction).

Some embodiments relate to methods of monitoring or treating a wound with the technology disclosed herein in conjunction with one or more of the following: advanced footwear, turning a patient, offloading (such as, offloading diabetic foot ulcers), treatment of infection, systemix, antimicrobial, antibiotics, surgery, removal of tissue, affecting blood flow, physiotherapy, exercise, bathing, nutrition, hydration, nerve stimulation, ultrasound, electrostimulation, oxygen therapy, microwave therapy, active agents ozone, antibiotics, antimicrobials, or the like.

Alternatively or additionally, a wound may be treated using topical negative pressure or traditional advanced wound care, which is not aided by the using of applied negative pressure (may also be referred to as non-negative pressure therapy).

Advanced wound care may include use of an absorbent dressing, an occlusive dressing, use of an antimicrobial or debriding agents in a wound dressing or adjunct, a pad (for example, a cushioning or compressive therapy, such as stockings or bandages), or the like.

In some embodiments, treatment of such wounds can be performed using traditional wound care, wherein a dressing can be applied to the wound to facilitate and promote healing of the wound.

Some embodiments relate to methods of manufacturing a wound dressing including providing a wound dressing as disclosed herein.

The wound dressings that may be utilized in conjunction with the disclosed technology include any known dressing in the art. The technology is applicable to negative pressure therapy treatment as well as non-negative pressure therapy treatment.

In some embodiments, a wound dressing includes one or more absorbent layer(s). The absorbent layer may be a foam or a superabsorbent. In some embodiments, wound dressings may include a dressing layer including a polysaccharide or modified polysaccharide, a polyvinylpyrrolidone, a polyvinyl alcohol, a polyvinyl ether, a polyurethane, a polyacrylate, a polyacrylamide, collagen, or gelatin or mixtures thereof. Dressing layers including the polymers listed are known in the art as being useful for forming a wound dressing layer for either negative pressure therapy or non-negative pressure therapy.

In some embodiments, the polymer matrix may be a polysaccharide or modified polysaccharide. In some embodiments, the polymer matrix may be a cellulose. Cellulose material may include hydrophilically modified cellulose such as methyl cellulose, carboxymethyl cellulose (CMC), carboxymethyl cellulose (CEC), ethyl cellulose, propyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, carboxyethyl sulphonate cellulose, cellulose alkyl sulphonate, or mixtures thereof.

In certain embodiments, cellulose material may be cellulose alkyl sulphonate. The alkyl moiety of the alkyl sulphonate substituent group may have an alkyl group having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, or butyl. The alkyl moiety may be branched or unbranched, and hence suitable propyl sulphonate substituents may be 1- or 2-methyl- ethylsulphonate. Butyl sulphonate substituents may be 2-ethyl-ethylsulphonate, 2,2-dimethyl- ethylsulphonate, or l ,2-dimethyl-ethylsulphonate. The alkyl sulphonate substituent group may be ethyl sulphonate. The cellulose alkyl sulphonate is described in WO 10061225, US2016/1 14074, US2006/0142560, or US 5,703,225, the disclosures of which are hereby incorporated by reference in their entirety.

Cellulose alkyl sulfonates may have varying degrees of substitution, the chain length of the cellulose backbone structure, and the structure of the alkyl sulfonate substituent. Solubility and absorbency are largely dependent on the degree of substitution: as the degree of substitution is increased, the cellulose alkyl sulfonate becomes increasingly soluble. It follows that, as solubility increases, absorbency increases.

In some embodiments, a wound dressing also includes a top or cover layer. The thickness of the wound dressing disclosed herein may be between 1 to 20, or 2 to 10, or 3 to 7 mm.

Wound Dressing for Standalone Use

In some embodiments, the disclosed technology may be used in conjunction with a non-negative pressure dressing. A non-negative pressure wound dressing suitable for providing protection at a wound site may comprise:

an absorbent layer for absorbing wound exudate and

an obscuring element for at least partially obscuring a view of wound exudate absorbed by the absorbent layer in use.

The obscuring element may be partially translucent. The obscuring element may be a masking layer. The non-negative pressure wound dressing may further include a region in or adjacent the obscuring element for allowing viewing of the absorbent layer. For example, the obscuring element layer may be provided over a central region of the absorbent layer and not over a border region of the absorbent layer. In some embodiments, the obscuring element is of hydrophilic material or is coated with a hydrophilic material. The obscuring element may include a three-dimensional knitted spacer fabric. The spacer fabric is known in the art and may include a knitted spacer fabric layer. The obscuring element may further include an indicator for indicating the need to change the dressing.

In some embodiments, the obscuring element is provided as a layer at least partially over the absorbent layer, further from a wound site than the absorbent layer in use.

The non-negative pressure wound dressing may further include a plurality of openings in the obscuring element for allowing fluid to move therethrough. The obscuring element may comprise, or may be coated with, a material having size-exclusion properties for selectively permitting or preventing passage of molecules of a predetermined size or weight.

The obscuring element may be configured to at least partially mask light radiation having wavelength of 600 nm and less. The obscuring element may be configured to reduce light absorption by 50% or more. The obscuring element may be configured to yield a CIE L* value of 50 or more, and optionally 70 or more. In some embodiments, the obscuring element may be configured to yield a CIE L* value of 70 or more.

In some embodiments, the non-negative pressure wound dressing may further include at least one of a wound contact layer, a foam layer, an odor control element, a pressure- resistant layer and a cover layer.

In some embodiments, the cover layer is present, and the cover layer is a translucent film. Typically, the translucent film has a moisture vapour permeability of 500g/m2/24hours or more. The translucent film may be a bacterial barrier.

In some embodiments, the non-negative pressure wound dressing as disclosed herein includes the wound contact layer and the absorbent layer overlies the wound contact layer. The wound contact layer carries an adhesive portion for forming a substantially fluid tight seal over the wound site.

The non- negative pressure wound dressing as disclosed herein may include the obscuring element and the absorbent layer being provided as a single layer. In some embodiments, the non-negative pressure wound dressing disclosed herein includes the foam layer, and the obscuring element is of a material including components that may be displaced or broken by movement of the obscuring element.

In some embodiments, the non-negative pressure wound dressing includes an odor control element, and in another embodiment the dressing does not include an odor control element. When present, the odor control element may be dispersed within or adjacent the absorbent layer or the obscuring element. Alternatively, when present the odor control element may be provided as a layer sandwiched between the foam layer and the absorbent layer.

In some embodiments, the disclosed technology for a non-negative pressure wound dressing includes a method of manufacturing a wound dressing, including: providing an absorbent layer for absorbing wound exudate; and providing an obscuring element for at least partially obscuring a view of wound exudate absorbed by the absorbent layer in use.

In some embodiments, the non-negative pressure wound dressing is may be suitable for providing protection at a wound site, including: an absorbent layer for absorbing wound exudate; and a shielding layer provided over the absorbent layer, and further from a wound facing side of the wound dressing than the absorbent layer. The shielding layer may be provided directly over the absorbent layer. In some embodiments, the shielding layer includes a three-dimensional spacer fabric layer.

The shielding layer increases the area over which a pressure applied to the dressing is transferred by 25% or more or the initial area of application. For example the shielding layer increases the area over which a pressure applied to the dressing is transferred by 50% or more, and optionally by 100% or more, and optionally by 200% or more.

The shielding layer may include 2 or more sub-layers, wherein a first sub-layer includes through holes and a further sub-layer includes through holes and the through holes of the first sub- layer are offset from the through holes of the further sub-layer.

The non- negative pressure wound dressing as disclosed herein may further include a permeable cover layer for allowing the transmission of gas and vapor therethrough, the cover layer provided over the shielding layer, wherein through holes of the cover layer are offset from through holes of the shielding layer. The non-negative pressure wound dressing may be suitable for treatment of pressure ulcers.

A more detailed description of the non-negative pressure dressing disclosed hereinabove is provided in W02013007973, the entirety of which is hereby incorporated by reference.

In some embodiments, the non-negative pressure wound dressing may be a multi layered wound dressing including: a fibrous absorbent layer for absorbing exudate from a wound site; and a support layer configured to reduce shrinkage of at least a portion of the wound dressing.

In some embodiments, the multi-layered wound dressing disclosed herein, further includes a liquid impermeable film layer, wherein the support layer is located between the absorbent layer and the film layer.

The support layer disclosed herein may include a net. The net may include a geometric structure having a plurality of substantially geometric apertures extending therethrough. The geometric structure may for example include a plurality of bosses substantially evenly spaced and joined by polymer strands to form the substantially geometric apertures between the polymer strands.

The net may be formed from high density polyethylene. The apertures may have an area from 0.005 to 0.32 mm2. The support layer may have a tensile strength from 0.05 to 0.06 Nm. The support layer may have a thickness of from 50 to 150 pm.

In some embodiments, the support layer is located directly adjacent the absorbent layer. Typically, the support layer is bonded to fibers in a top surface of the absorbent layer. The support layer may further include a bonding layer, wherein the support layer is heat laminated to the fibers in the absorbent layer via the bonding layer. The bonding layer may include a low melting point adhesive such as ethylene -vinyl acetate adhesive.

In some embodiments, the multi-layered wound dressing disclosed herein further includes an adhesive layer attaching the film layer to the support layer.

In some embodiments, the multi-layered wound dressing disclosed herein further includes a wound contact layer located adjacent the absorbent layer for positioning adjacent a wound. The multi-layered wound dressing may further include a fluid transport layer between the wound contact layer and the absorbent layer for transporting exudate away from a wound into the absorbent layer.

A more detailed description of the multi-layered wound dressing disclosed hereinabove is provided in GB patent application filed on 28 October 2016 with appbcation number GB1618298.2, the entirety ofwhich is hereby incorporated by reference.

In some embodiments, the disclosed technology may be incorporated in a wound dressing including a vertically lapped material including: a first layer of an absorbing layer of material, and a second layer of material, wherein the first layer being constructed from at least one layer of non-woven textile fibers, the non-woven textile fibers being folded into a plurabty of folds to form a pleated structure. In some embodiments, the wound dressing further includes a second layer of material that is temporarily or permanently connected to the first layer of material. Typically the vertically lapped material has been slitted.

In some embodiments, the first layer has a pleated structure having a depth determined by the depth of pleats or by the slitting width. The first layer of material may be a moldable, lightweight, fiber-based material, blend of material or composition layer.

The first layer of material may include one or more of manufactured fibers from synthetic, natural or inorganic polymers, natural fibers of a cellulosic, proteinaceous or mineral source.

The wound dressing may include two or more layers of the absorbing layer of material vertically lapped material stacked one on top of the other, wherein the two or more layers have the same or different densities or composition.

The wound dressing may in some embodiments include only one layer of the absorbing layer of material vertically lapped material.

The absorbing layer of material is a blend of natural or synthetic, organic or inorganic fibers, and binder fibers, or bicomponent fibers typically PET with a low melt temperature PET coating to soften at specified temperatures and to act as a bonding agent in the overall blend.

In some embodiments, the absorbing layer of material may be a blend of 5 to 95 % thermoplastic polymer, and 5 to 95 wt % of a cellulose or derivative thereof. In some embodiments, the wound dressing disclosed herein has a second layer includes a foam or a dressing fixative. The foam may be a polyurethane foam. The polyurethane foam may have an open or closed pore structure. The dressing fixative may include bandages, tape, gauze, or backing layer.

In some embodiments, the wound dressing as disclosed herein includes the absorbing layer of material connected directly to a second layer by lamination or by an adhesive, and the second layer is connected to a dressing fixative layer. The adhesive may be an acrylic adhesive, or a silicone adhesive.

In some embodiments, the wound dressing as disclosed herein further includes layer of a superabsorbent fiber, or a viscose fiber or a polyester fiber.

In some embodiments, the wound dressing as disclosed herein further includes a backing layer. The backing layer may be a transparent or opaque film. Typically the backing layer includes a polyurethane film (typically a transparent polyurethane film).

A more detailed description of the multi-layered wound dressing disclosed hereinabove is provided in GB patent applications filed on 12 December 2016 with application number GB1621057.7; and 22 June 2017 with application number GB1709987.0, the entirety of each of which is hereby incorporated by reference.

In some embodiments, the non-negative pressure wound dressing may include an absorbent component for a wound dressing, the component including a wound contacting layer including gel forming fibers bound to a foam layer, wherein the foam layer is bound directly to the wound contact layer by an adhesive, polymer based melt layer, by flame lamination or by ultrasound.

The absorbent component may be in a sheet form. The wound contacting layer may include a layer of woven or non-woven or knitted gel forming fibers. The foam layer may be an open cell foam, or closed cell foam, typically an open cell foam. The foam layer is a hydrophilic foam.

The wound dressing may include the component that forms an island in direct contact with the wound surrounded by periphery of adhesive that adheres the dressing to the wound. The adhesive may be a silicone or acrylic adhesive, typically a silicone adhesive. The wound dressing may be covered by a film layer on the surface of the dressing furthest from the wound. A more detailed description of the wound dressing of this type hereinabove is provided in EP2498829, the entirety of which is hereby incorporated by reference.

In some embodiments, the non-negative pressure wound dressing may include a multi layered wound dressing for use on wounds producing high levels of exudate, characterized in that the dressing including: a transmission layer having an MVTR of at least 300 gm2/24 hours, an absorbent core including gel forming fibers capable of absorbing and retaining exudate, a wound contacting layer including gel forming fibers which transmits exudate to the absorbent core and a keying layer positioned on the absorbent core, the absorbent core and wound contacting layer limiting the lateral spread of exudate in the dressing to the region of the wound.

The wound dressing may be capable of handling at least 6g (or 8g and 15g) of fluid per l0cm2 of dressing in 24 hours. The wound dressing may include gel forming fibers that are chemically modified cellulosic fibers in the form of a fabric. The fibers may include carboxymethylated cellulose fibers, typically sodium carboxymethylcellulose fiber. The wound dressing may include a wound contact layer with a lateral wicking rate from 5mm per minute to 40mm per minute. The wound contact layer may have a fiber density between 25gm2 and 55gm2, such as 35gm2. The absorbent core may have an absorbency of exudate of at least lOg/g, and typically a rate of lateral wicking of less the 20mm per minute. The absorbent core may have a blend in the range of up to 25% cellulosic fibers by weight and 75% to 100% gel forming fibers by weight.

Alternatively, the absorbent core may have a blend in the range of up to 50% cellulosic fibers by weight and 50% to 100% gel forming fibers by weight. For example the blend is in the range of 50% cellulosic fibers by weight and 50% gel forming fibers by weight. The fiber density in the absorbent core may be between l50gm2 and 250gm2, or about 200 gm2.

The wound dressing when wet may have shrinkage that is less than 25 % or less than 15 % of its original size/dimension. The wound dressing may include a transmission layer and the layer is a foam. The transmission layer may be a polyurethane foam laminated to a polyurethane film. The wound dressing may include one or more layers selected from the group including a soluble medicated film layer; an odor-absorbing layer; a spreading layer and an additional adhesive layer. The wound dressing may be 2mm and 4mm thick. The wound dressing may be characterized in that the keying layer bonds the absorbent core to a neighboring layer. In some embodiments, the keying layer may be positioned on either the wound facing side of the absorbent core or the non-wound facing side of the absorbent core. In some embodiments, the keying layer is positioned between the absorbent core and the wound contact layer. The keying layer is a polyamide web.

A more detailed description of the wound dressing of this type hereinabove is provided in EP 1718257, the entirety of which is hereby incorporated by reference.

In some embodiments, the non-negative pressure wound dressing may be a compression bandage. Compression bandages are known for use in the treatment of oedema and other venous and lymphatic disorders, for example, of the lower limbs.

Compression bandage systems typically employ multiple layers including a padding layer between the skin and the compression layer or layers. The compression bandage may be useful for wounds such as handling venous leg ulcers.

The compression bandage in some embodiments may include a bandage system including an inner skin facing layer and an elastic outer layer, the inner layer including a first ply of foam and a second ply of an absorbent nonwoven web, the inner layer and outer layer being sufficiently elongated so as to be capable of being wound about a patient's limb. A compression bandage of this type is disclosed in W099/58090, the entirety of which is hereby incorporated by reference.

In some embodiments, the compression bandage system comprises: a) an inner skin facing, elongated, elastic bandage including: (i) an elongated, elastic substrate, and (ii) an elongated layer of foam, said foam layer being affixed to a face of said substrate and extending 33% or more across said face of substrate in transverse direction and 67% or more across said face of substrate in longitudinal direction; and b) an outer, elongated, self-adhering elastic bandage; said bandage having a compressive force when extended; wherein, in use, said foam layer of the inner bandage faces the skin and the outer bandage overlies the inner bandage. A compression bandage of this type is disclosed in W02006/1 10527, the entirety of which is hereby incorporated by reference. In some embodiments other compression bandage systems such as those disclosed in US 6,759,566 and US 2002/0099318, the entirety of each of which is hereby incorporated by reference.

Another example of a multi-layer wound dressing is the ALLEVYN dressing, including ALLEVYN Life and ALLEVYN Gentle Border dressings, available from Smith & Nephew, which include a moist wound environment dressing that is used to treat the wound.

Pressure Ulcers

Pressure ulcers may typically develop on skin that covers bony areas, such as heels, ankles, hips, shoulder blades, spine, elbows, back of the head, and tailbone as illustrated in Ligure 1. Persons whose mobility is limited due to age or medical conditions are at an increased risk of developing pressure ulcers because of their inability to change positions while sitting or lying down. Management and treatment of pressure ulcers include repositioning of the injured limb or body part and using support surfaces, such as a mattress, cushion, or the like.

Also shown in Ligure 1, a diabetic foot ulcer (DLU) is a common pressure ulcer which occurs with higher frequency and intensity in the diabetic population. Offloading the wound by using cushioned footwear, such as a support boot, cast, shoe, etc. is a common way of management and treatment of diabetic foot ulcers. However, as many offloading devices are removable, it has been found that patient non-compliance with the offloading devices plays a large role in the delayed healing of diabetic foot ulcers. The device described herein can offer a way to allow clinicians to monitor whether a patient is complying with offloading his or her foot. Although this specification is directed to monitoring the load of a foot, the disclosed embodiments can also be reconfigured to monitor load bearing regions of other parts of the body such as, but not limited to, bony areas, such as heels, ankles, buttocks, hips, shoulder blades, spine, elbows, back of the head, and the tailbone.

Loading Monitoring

In some cases, loading of a patient’s body part, such as a foot, can be monitored by a device or apparatus that attaches to the body part. In case of attachment to the foot, the device can be attached to the sole of the foot to detect or measure loading of the foot. Because weight can be placed on the device when the foot is loaded, the device can be at least one of flexible, conformable, small, or the like in order to minimize pain or discomfort. As described herein, the device can be designed to protect the electronic components from malfunctioning or breaking due to force being applied during the loading. Figure 2 illustrates a load-measuring apparatus or device 200 according to some embodiments. The device 200 can be attached to the patient’s body part, such as to the foot, to measure loading of the body part. The device can be attached by adhesive (which can be positioned on a housing of the device), strips, bandages, tape, wound dressing, or the like. The device 200 can, in some cases, monitor loading based on monitoring the force applied to the body part (for example, weight borne by the foot).

In some cases, the load- measuring device comprises of an upper housing 202, a cushion 204, a cushion 206 (such as, a smaller cushion insert, a circuit board 208, a port (as described herein) 210, and a lower housing 212. The upper housing 202 and lower housing 212 can be used to support, secure, or enclose one or more sensors and the board 208. The upper housing 202 and lower housing 212 can be made of hard or conformable and flexible material, such as one or more of thermoplastic elastomer (TPE) (such as, Verbatim PRIMAlloy), polyurethane, thermoplastic polyurethane (TPU), silicone, polycarbonate, polyethylene, polyimide, polyamide, polyester, polyethelene tetraphthalate (PET), polybutalene tetreaphthalate (PBT), polyethylene naphthalate (PEN), polyetherimide (PEI), along with various fluropolymers (FEP) and copolymers, or another suitable material.

The upper housing 202 and lower housing 212 can be made using 3D printing, injection molding, casting, compression molding, transfer molding, or with other molding or casting methods. The lower housing 212 can further comprise a support pin 216 and the cushion 214. The lower housing 212 and upper housing 202 can be connected when assembled. The support pin 216 can be used to secure a sensor. There can be two holes at either end of a sensor. In cases when a sensor is folded (for example, in half), both holes can be superimposed on each other and slotted onto the support pin 216. The support pin 216 can have a ridge or flared edges to secure the sensor from lifting off the board 208. An additional component, such as a washer or plastic layer, can be placed over the sensor via the support pin 216 to form an additional layer to prevent the sensor from lifting off the board 208. When put together, the edges of the housing define a set volume between the upper housing 202 and lower housing 212. The cushions 204 and 206 as well as 214 can provide cushioning to the device and protection of internal componentry. Cushions 204, small 206, and lower cushion 214 can be made of foam or another suitable material and can be a removable insert. In some cases, one or more of the cushions 204, 206, or 214 can be omitted or duplicated.

The board 208 is described in further detail herein. The board 208 can include one or more sensors for detecting loading of the body part. In some cases, a strain sensor, pressure sensor, or the like can be used. For example, an EAP strain sensor manufactured by Parker Hannfiin can be used. The one or more sensors can be small. Additionally or alternatively, at least one sensor can be folded to reduce its size. For instance, a sensor can be folded down in size (for example, folded in half) to create a smaller device or into a shape that is customized to the patient or device. Additionally or alternatively, at least one sensor can be stretched to increase its size or change its shape. For instance, the sensor can be stretched to fit a larger device or into a shape that is customized to the patient or device.

In some cases, the load-measuring device 200 uses an internal power source. In some cases, the internal power source is a battery. In some cases, the battery can be recharged or replaced. In some cases, the internal power source uses motion of the user to recharge the power source. In some cases, the housing can be designed to be re-opened. In some cases, the housing can be connected with a mechanical hinge, natural hinge, or with a snap-lock feature. In some cases, the load-measuring device 200 can comprise a component that provides an uncomfortable stimulus, such as a shock or an uncomfortable texture, which discourages a patient to put any load on his or her body part. In some cases, the load-measuring device 200 can also have a one or more of a moisture detector or an infection detector.

In some cases, any of the components disclosed herein can be designed to be modular, interchangeable, and/or reusable. In some cases, the length of the device 200 can be about 85 mm. In some cases, the length of the device can be about 10 mm or less or more, about 20 mm or less or more, about 30 mm or less or more, about 40 mm or less or more, about 50 mm or less or more, about 60 mm or less or more, about 70 mm or less or more, about 80 mm or less or more, about 90 mm or less or more, about 100 mm or less or more, about 150 mm or less or more, about 200 mm or less or more, etc.

In some cases, the width of the device 200 can be about 25 mm. In some cases, the width of the device can be about 50 mm or less or more, about 40 mm or less or more, about 30 mm or less or more, about 20 mm or less or more, about 10 mm or less or more, 5 mm or less or more, 1 mm or less or more, etc. In some cases, the height of the device can be about 10 mm or less or more, about 20 mm or less or more, about 15 mm or less or more, about 10 mm or less or more, about 5 mm or less or more, about 1 mm or less or more, about 0.5 mm or less or more, or etc. In some cases, the housing and device can mimic the shape and size of the patient’s foot or parts of the patient’s foot.

Figure 3 illustrates electronics 300 of the apparatus 200, including the circuit board 208. The board 208 can include one or more sensors 302, a connector 304 and a port 308 connected to an external device. A cover 310 can cover at least a portion of the board 208. The board 208 also has a cutaway portion 312 for securing the sensor to the support pin 216 as shown in Figure 2. The sensor 302 can be attached to the housing. As described herein, the sensor 302 can be a strain sensor or gauge 302 that measures strain on a body part. In some cases, the strain gauge can measure strain on the housing of the device, which can be correlated with strain on, for instance, the foot when the device is placed on the foot.

In some cases, the strain gauge can include a dielectric polymer sandwiched between two (or more) electrodes. As the load-measuring device is deformed, which causes deformation of the strain gauge, distance between the electrodes changes (for example, gets smaller), causing the electrical capacitance to change. The change in the capacitance can be indicative of loading. In some cases, the strain gauge includes an insulating flexible backing which supports a metallic foil pattern. The strain gauge can be attached to the housing by a suitable adhesive. As the load-measuring device is deformed, the foil is deformed, causing the electrical capacitance or resistance to change. This change can be measured by a Wheatstone bridge, and can be related to the strain by the gauge factor quantity. In some cases, semiconductor strain gauges (such as, piezoresistors) can be used. Nanoparticle -based strain gauges can also be used. Mercury-in-rubber strain gauges can be used. Fiber optic sensing can also be employed to measure strain along an optical fiber. Measurements can be distributed along the fiber, or taken at predetermined points on the fiber. Microscale strain gauges can be used. As alternative to piezoresistive strain gauges, integrated optical ring resonators can be used. Capacitive strain gauges can be used. Vibrating wire strain gauges can be used. Piezoelectric strain gauges can be used. In some cases, the strain gauge 302 can be folded or manipulated to fit in custom sized housing. The board 208 can include one or more indicators, such as visual, audible, tactile, haptic, or the like to indicate status of the device. For example, a light emitting diode (LED) visual indicator can be used, for example 404 in Figure 4A.

The circuit board 208 can include one or more controllers or processors. One or more processors can control, determine, or provide indication that the foot is loaded based on the data associated with the output of the one or more sensors. The board 208 can also have an independent power source or can be powered from an external power source, such as through the port 308. In some cases, a substantially non-extensible or non- stretchable coating can be used to at least partially shield or protect the electronics from stress or strain, coming into contact with fluids, or the like. This coating can be one or more of a suitable adhesive, epoxy, polyester, polyimide, polyamide, PET, PBT, or another type of material with a high Young’s modulus, such as Dymax 1901-M or 900 l-E Dymax. The coating can be thin, such as about 100 microns thick, less than about 100 microns thick, or more than about 100 microns thick. The coating can be applied and cured using one or more of UV, light, or thermal curing. In some implementations, the coating can be applied to or support a connector 304 between the sensor 302 and other components on the board 208. In some cases, the board can be a substantially flexible circuit board.

In some cases, structures or harder/non-stretchable materials can be used to reinforce the board 208 at areas such as, but not limited to, the circuit board connector 304, the port 308, or any other area of the board 208. In some cases, the board 208 can contain a wired or wireless transmitter that can send data over to a processing device or display device. In some cases, the board 208 can include a memory storage for the recorded data. In some cases, the port 308 can be used to recharge an internal power source. In some cases, the port 308 can be used to communicate data to or from one or more components on the board 208, such as a processor, sensor, or the like. The port 308 cam allow for connection to a computing device. In some cases, the port 308 can be designed to be configured with a USB cable, micro-USB cable, thunder cable, or etc. In some cases, the device 200 can transmit or receive and receive data wirelessly.

Figures 4A and 4B illustrate an encapsulated load- measuring device or apparatus 400 according to some embodiments. In Figure 4A, a status indicator, such as a light source 404, can be used. In Figure 4B, the port 308 can remain uncovered. The device 400 can be substantially encapsulated in coating (which can also be referred to as conformal coating). Coating 402 can be applied to the upper and lower housing 202, 212 as shown in Figure 2 to substantially encapsulate the housing of the device. This can be advantageous when the housing is not biocompatible or hydrophobic. Coating 402 can provide cushioning for the device 400. Coating 402 can be biocompatible. Coating 402 can be hydrophobic. Coating 402 can be substantially stretchable or extensible. Coating 402 can be the same or different for both sides of upper and lower housing 202, 212. As described herein, coating 402 can be substantially stretchable or extensible and can include one or more of a suitable polymer, adhesive, such as Dymax 1072-M UV, light, or thermal curable or cured adhesive, Optimax adhesive, Dymax 1 165M UV/visible light curable or cured adhesive, parylene (such as, Parylene C), silicone, epoxy, urethane, acrylated urethane, or another suitable material. The coating can be applied and cured using one or more of UV, light, or thermal curing. In some cases, acrylated urethanes can be used as coating 402 as these polymers have suitable adhesive properties and extensibility. Coating 402 can fluoresce when placed under ultraviolet or other types of light. The fluorescing capabihty may be used in inspection phases when determining the quality of the coating apphcation, integrity of the coating, or the hke.

In some cases, the load-measuring device, such as the device 200 or 400, may not include a housing, such as the upper and lower housing 202, 212. Without the housing, the one or more sensors can be formed or transformed into one or more of shape(s) or dimension(s) to conform to the body part or region of interest. This can increase comfort and facilitate collection of measurements over a larger area. The one or more sensors can be flexible or extensible or substantially flexible or extensible. For example, the one or more sensors can be stretched or lengthened or folded in one or more directions. As another example, the one or more sensors can be rolled (such as rolled up), twisted, curled, or the like. For instance, the one or more sensors can be formed into a band, such an elastic band. To facilitate robustness and to protect the device from damage or malfunction during use, the one or more sensors can be securely connected to the circuit board using, for example, the substantially non-extensible or non- stretchable coating described herein. The coating can be used to connect the one or more sensors to the circuit board, for instance, using adhesion. As described herein, such coating can be one or more of a suitable adhesive, epoxy, polyester, polyimide, polyamide, PET, PBT, or another type of material with a high Young’s modulus, such as Dymax 1901-M or 9001-E Dymax.

The circuit board may be enclosed in a housing even when the outer housing, such as the upper and lower housing 202, 212, is not used. The material of the circuit board housing can be any of the housing materials described herein, such as polycarbonate (which is a hard material) or silicone (which is a flexible material). The one or more sensors may not be enclosed in the housing as described herein.

Figure 5 illustrates load graphs 500 and 510 according to some embodiments. The illustrated graphs can be associated with load detected by one or more sensors of a device, such as the device 200 or 400. For example, the graphs can be a minimum force graph 500 and a maximum force graph 510 that can be detected by a strain gauge due to loading. The graphs 500, 510 both have a y-axis 502 of amplitude of the detected signal and an x-axis of time 504. Calibration back to zero 506 indicates when the strain gauge is calibrated. The curves increase when a force is applied 508. Once the strain gauge is calibrated, which can be performed using one or more processors, loading can be detected by an increase in amplitude at 508 when force is applied. This increase can be detected by comparing raw or processed (for example, low-pass filtered to remove noise) data produced by the strain gauge to one or more thresholds. As illustrated, the value of increase in amplitude depends on the amount of force applied. For example, loading of the foot by a smaller person can be illustrated in graph 500 (minimum force), and loading of the foot by a larger person can be illustrated in graph 510 (maximum force). This way, regardless of the weight of a patient, loading can be detected reliably. Additionally or alternatively, unloading can be detected by detecting an amplitude drop (not shown). Duration of time during which the body part has been loaded can be determined. This can be performed by measuring a difference between a first time at which has been determined that the foot is loaded and a second time at which it has been determined that the foot is unloaded. Indication of the duration of time can be provided as described herein. The sensor can be calibrated (as described herein) for a particular patient when the device is used on that particular patient. Other Variations

Although this disclosure describes certain embodiments, it will be understood by those skilled in the art that many aspects of the methods and devices shown and described in the present disclosure may be differently combined and/or modified to form still further embodiments or acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure. Indeed, a wide variety of designs and approaches are possible and are within the scope of this disclosure. No feature, structure, or step disclosed herein is essential or indispensable. Moreover, while illustrative embodiments have been described herein, the scope of any and all embodiments having equivalent elements, modifications, omissions, combinations (for example, of aspects across various embodiments), substitutions, adaptations and/or alterations as would be appreciated by those in the art based on the present disclosure. While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of protection.

Features, materials, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example are to be understood to be applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The protection is not restricted to the details of any foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of protection. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the processes illustrated and/or disclosed may differ from those shown in the figures. Depending on the embodiment, certain of the steps described above may be removed, others may be added. For example, the actual steps and/or order of steps taken in the disclosed processes may differ from those shown in the figure. Depending on the embodiment, certain of the steps described above may be removed, others may be added. For instance, the various components illustrated in the figures may be implemented as software and/or firmware on a processor, controller, ASIC, FPGA, and/or dedicated hardware. Hardware components, such as processors, ASICs, FPGAs, and the like, can include logic circuitry.

Furthermore, certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations, one or more features from a claimed combination can, in some cases, be excised from the combination, and the combination may be claimed as a subcombination or variation of a subcombination.

Moreover, while operations may be depicted in the drawings or described in the specification in a particular order, such operations need not be performed in the particular order shown or in sequential order, or that all operations be performed, to achieve desirable results. Other operations that are not depicted or described can be incorporated in the example methods and processes. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the described operations. Further, the operations may be rearranged or reordered in other implementations. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the processes illustrated and/or disclosed may differ from those shown in the figures. Depending on the embodiment, certain of the steps described above may be removed, others may be added. Furthermore, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure. Also, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products.

For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

Conditional language, such as“can,”“could,”“might,” or“may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and/or steps are included or are to be performed in any particular embodiment. The terms“comprising,”“including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term“or” means one, some, or all of the elements in the list. Further, the term“each,” as used herein, in addition to having its ordinary meaning, can mean any subset of a set of elements to which the term“each” is applied.

Conjunctive language such as the phrase“at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one ofY, and at least one of Z.

Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and“substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms“approximately”,“about”,“generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. As another example, in certain embodiments, the terms“generally parallel” and “substantially parallel” refer to a value, amount, or characteristic that departs from exactly parallel by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, 0.1 degree, or otherwise.

The scope of the present disclosure is not intended to be limited by the specific disclosures of preferred embodiments in this section or elsewhere in this specification, and may be defined by claims as presented in this section or elsewhere in this specification or as presented in the future. The language of the claims is to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non- exclusive.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for monitoring load bearing of a foot, the apparatus comprising: a housing formed from a substantially flexible and conformable material, the housing configured to be attached to the foot, the housing defining an interior volume; a sensor positioned in the interior volume, the sensor configured to provide data associated with strain on the housing as a result of loading of the foot; and

a controller positioned in the interior volume, the controller configured to, based on the data associated with the strain on the housing produced by the sensor, determine and provide indication that the foot is loaded,

wherein the housing is at least partially encapsulated in a conformal coating configured to provide cushioning when the housing is attached to the foot.

2. The apparatus of any of the preceding claims, wherein the sensor comprises a strain gauge.

3. The apparatus of claims 2 wherein the sensor is folded in half.

4. The apparatus of any of the preceding claims, wherein the sensor is attached to the housing.

5. The apparatus of any of the preceding claims, wherein the controller is configured to determine that the foot is loaded based on comparing the data associated with the strain on the housing to a loading threshold.

6. The apparatus of any of the preceding claims, wherein the controller is further configured to, based on the data produced by the sensor and indicative of the strain on the housing, determine and provide indication that the foot is unloaded.

7. The apparatus of any of the preceding claims, wherein the controller is further configured to determine a duration of time during which the foot is loaded based on determining a difference between a first time during which the foot is determined to have been loaded and a second time during which the foot is determined to have been unloaded.

8. The apparatus of any of the preceding claims, wherein the controller is further configured to calibrate the sensor.

9. The apparatus of any of the preceding claims, wherein the at least one of the controller or sensor is positioned on a circuit board.

10. The apparatus of claim 9, further comprising a cushioning positioned over at least a portion of the circuit board.

1 1. The apparatus of any of claims 9 to 10, wherein at least a portion of the circuit board includes a region of substantially non-stretchable material.

12. The apparatus of any of the preceding claims, wherein the conformal coating is substantially stretchable.

13. A method of operating the apparatus of any of the preceding claims.

14. An apparatus for monitoring load bearing of a body part, the apparatus comprising:

a sensor configured to be attached to the body part and to provide data associated with strain on the sensor as a result of loading of the body part; and

a circuit board comprising a controller, the controller configured to, based on the data associated with the strain produced by the sensor, determine and provide indication that the body part is loaded,

wherein the circuit board is at least partially encapsulated in a conformal coating configured to provide cushioning when apparatus is attached to the body part.

15. The apparatus of claim 14, further comprising a housing enclosing the circuit board.

16. The apparatus of claim 15, wherein the housing encloses the circuit board but not the sensor.

17. The apparatus of any of claims 14 to 16, wherein the sensor is attached to the circuit board.

18. The apparatus of claim 17, wherein the sensor is adhered to the circuit board.

19. The apparatus of claim 18, wherein the sensor is adhered to the circuit board with substantially non-stretchable coating.

20. The apparatus of any of claims 14 to 19, wherein the sensor is substantially flexible.

21. The apparatus of any of claims 14 to 20, wherein the sensor is stretched, folded, or rolled up.

22. A method of operating the apparatus of any of claims 14 to 21.