Patent Application
20090171259
The present invention is related to the field of hernia care and prevention and, more particularly, to a post-operative garment with particular elastic properties for the prevention of hernias.
Hernia is an abnormal protrusion of an organ or parts thereof through the wall of a body cavity. A special type of hernia is an incisional (ventral) hernia that may appear when persons have undergone surgery, where the incision goes through various tissues, and the tissue is thus weakened by the incision. The incision can be any cut or hole made in the skin possibly extending through the fascia. It includes midline, transverse, oblique or other incisions made during laparotomy, key-holes made during laparoscopy and trocar sites. The incidence of incisional hernia varies from a few percent to more than 30% depending on the reasons for surgery (diagnosis), operation procedures used and general wound healing ability of the patient. Incisional hernia can appear a relatively long time after the surgery, i.e., months or even years. The recurrence rate of hernia can be very high.
To protect the hernia incision after surgery, compression garments can be worn. These are particularly important to reduce the risk of wound healing complications relating to temporary increases in intraabdominal pressure. Intraabdominal pressure (IAP) is defined as the pressure concealed within the abdominal cavity and varies with respiration. Sudden large increases in IAP occurs i.e. when the user sneezes, coughs, moves, vomits or defecates as well as during heavy lifting and exercise. During such a peak in IAP the wound is subjected to a significant shear force, tending to pull the wound edges apart which may result in increased scar formation, wound rupture (dehiscence), later incisional hernia formation or other wound healing complications.
While compression garments can help protect the wound during healing, patients often find them uncomfortable. As a result, patients often do not comply with post-operative instructions, choosing instead to remove the garment and thereby increasing the risk of healing complications.
An example of a fitting garment for preventing spread of operative wound is known from WO0024349 which discloses a garment having support bodies made of a non-slip material sandwiching the operative wound and having non-stretchable panels fixed to the support bodies on their outer surface. The free ends of the panels are joined to each other over the wound so as to draw the support bodies towards the wound thereby preventing spread of the operative wound.
FR2039950 discloses a bandage made of elastic material which has a layer of non-stretchable material fixed at the abdominal region. The bandage further comprises three reinforcements adapted for attaching two straps supporting the groin area.
A need still exists for an effective hernia prevention and treatment device that provides the necessary compression while, at the same time, providing comfort and adjustability so that wearer compliance with post-operative instructions calling for the consistent wearing of such a device is increased.
The present invention is directed to a compression garment providing protection to a wound area or as a hernia prevention garment, which at the same time is comfortable to wear so as to increase compliance.
An object of the invention is to provide a garment having a supportive section of a material with a controlled stretch-profile for covering the wound or hernia area and where the garment has another section of an elastic material for providing the necessary compression and comfort for the patient. The supportive section of a material with a controlled stretch-profile provides a plate effect around the wound, so as to counteract further stretch in the material covering the wound.
A further object of the invention is to provide different garments having a supportive section and another section of an elastic material. Examples of the different garments are an abdominal binder or tube, an undershirt, underpants and a bodysuit.
The invention also provides a hernia prevention regimen using a garment with the two different materials sections.
A major aspect of the invention relates to a compression garment comprising two elastic sections, a linear elastic section being made of a material with linear elastic properties, and a progressive elastic section being made of a material with progressive elastic properties wherein the progressive elastic section below 20% extension has linear elastic material properties.
The boundary for the transition in the materials properties of the progressive elastic section may preferably be anywhere between 15% and 25% elongation, e.g. 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23% or 24%. It may even be as low as 10% or as high as 30%. Another wording for this boundary is lower strain limit.
The present invention may be worn by anyone recovering from hernia repair, trying to prevent hernia formation or other certain surgeries. Certain patient groups have a higher than average risk of wound rupture or hernia formation and will especially benefit from using the present invention. Such high-risk groups include the obese, diabetics, smokers, patients with chronic obstructive lung disease (COLD) and patients with abnormal collagen I/III ratio (e.g. patient suffering from abdominal aorta aneurysm). However, all patient groups will benefit from the comfort and support offered by the invention which reduces post-operative pain during movement and provides the patient with an increased sense of security, i.e. allowing an earlier mobilization of the patient. Fast mobilization of patients is the most important factor in avoiding post-operative complications and reducing lengths of hospital stay.
In the long-term perspective, the risk of developing incisional hernia or recurrence of a repaired hernia will be reduced, when using the garment of the invention.
Not only will the product according to the invention reduce the wound healing complications caused by sudden increases in IAP (Intra Abdominal Pressure), but a constant pressure is also applied to the wound area reducing the formation of edema, seroma and hematoma as known, e.g., from compression stockings.
An important part of the present invention relates to a supportive section of the compression garment with a controlled stretchability. If elastic fabric is placed on the wound there is a risk that the fabric will tend to tear the wound/bandage and stress the wound when the patient moves or is moved or handled by the caregiver. In contrast, when a supportive fabric with a controlled stretchability protects the wound, there is virtually no transverse stress.
The invention is based on the realization that a non-stretchable section of material is excellent in preventing wound rupture or hernia recurrence, but would cause complications due to abdominal compartment syndrome and would also be very uncomfortable to wear. An elastic or stretchable section of material would however not be able to prevent wound rupture or hernia recurrence but would provide the comfort and compression needed as well as allowing the necessary movement of the abdominal region. Therefore, a combination of a supportive section having a controlled stretchability with an elastic section would provide the necessary protection of the wound area while at the same time provide the necessary comfort for the user.
Another advantage is that a garment of a given size with such a supportive section provides a higher compression than a similar all-elastic garment of the same size. Thus, the supportive section provides a firm compression, which resembles a plate effect. This allows for a more elastic textile, and thus one that is more comfortable, and/or a smaller elongation compared to an all-elastic garment.
In an embodiment the supportive section (the progressive elastic section) reaches a maximum level of stretch where further stretch is impossible. Such a supportive section may be referred to as a substantially non-stretchable part or section.
In one embodiment of the invention the compression garment is a garment where the progressive elastic section is made of a material with non-linear elastic properties which has an increasing MoE within an extension of 20%-40% and which material is non-stretchable with an extension above 40% with a brittle rupture at increased force and where the force required for rupture is higher than 0.5N/mm.
The upper boundary for the transition between non-linear elastic material properties to non-stretchable material may be anywhere between 30% and 50%, e.g. 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44% or 45%.
Another embodiment of the compression garment is a garment where the progressive elastic section is made of a material with different linear elastic properties depending on the extension which material within an extension above 20% has linear elastic material properties with an MoE at least three times higher than the MoE of the material within an extension below 20%.
The MoE of the progressive elastic section above 20% elongation may be a factor of 2 to 10 greater than the MoE of the section below 20% elongation, e.g. a factor 3, 4, 5, 6, 7, 8 or 9.
The linear elastic section provides the elasticity needed to obtain compression, and at the same time making the garment able to be donned.
The progressive elastic section provides the support and protection of the wound area or the area likely to develop a hernia rupture. This is due to the fact that the progressive elastic section has a controlled extension profile meaning that the material is able to extend relatively easy up to 20% extension after which the resistance to extension is more pronounced. Eventually further extension may be impossible. The consequence of this extension profile is that a patient wearing a compression garment according to the invention would be able to breath and would not experience discomfort due to a totally inelastic garment section. However, when a sudden large increase in IAP occurs, the garment is able to control the movement of the abdominal wall in the weak area surrounding the wound or hernia, thereby preventing wound rupture and a recurrence of hernia. Example 5 illustrates the difference in strain in the progressive elastic (supportive) and the elastic section.
By a progressive elastic section that covers an incision is essentially meant a homogeneous, supportive section of the garment. Prior art garments might have non-stretchable parts in the shape of zippers, seams, plates etc., but these are not suitable for the present invention which is directed to a supportive section with a controlled stretchability, preferably textile, that covers a wound arising from an incision. Such a part cannot comprise a zipper, for example, as that structure would conflict with the healing process and the sensitive skin around the wound.
The combination of the two elastic sections provides a unique garment, which at the same time is comfortable to wear and provides the necessary protection for the weak area of the abdominal wall.
In one embodiment the progressive elastic section of the material is made of a layered material where the layers have different material properties, a first layer having linear elastic material properties and another layer being slightly oversized compared to the first layer. This layered structure makes it possible to carefully control the extension profile of the material as the degree of over-sizing determines at which extension point the influence of the material properties of the oversized layer begins. This corresponds to the transition at the lower strain limit.
It is preferred that the first layer of the layered material corresponds to the material of the linear elastic section of the garment. This makes it possible to conceal the supportive progressive elastic section in the garment hence making the garment look like a regular non-supportive garment.
By selecting the oversized layer to be made of a virtually non-stretchable fabric or a fabric with a much higher MoE, e.g. three times the material of the first layer it is possible to control the stretchability of the layered structure.
The oversized layer has to be attached at both sides to the circular tube or binder of the compression garment. This ensures that expansion of the tube or binder in the radial direction does not cause noticeable expansion of the part of the garment intended to protect the wound. If the oversized layer were attached in only one side, the garment would act as if the supportive section was not present. The oversized layer may be attached by detachment components.
If the oversized layer is made of a virtually non-stretchable fabric it is preferred that the material has holes so it is possible to slightly deform the material. This makes the transition between the influence from the first and second layer of the garment less pronounced and hence the garment will be more comfortable to wear.
Preferably the oversized layer has holes corresponding to 25-50% of the area of the oversized layer, more preferred 30%, 35%, 40% or 45%.
A suitable yarn for making such a non-stretchable material is polyamide filament yarn.
The linear elastic material in the linear elastic section of garment has an MoE of 0.2-1.0 N/mm where the MoE is defined as illustrated in Example 1. An MoE of this order enables the material to be stretched easily while at the same time allowing the garment to provide the desired degree of compression to the patient.
The linear elastic section may have zones with different linear elastic properties thereby providing a three-dimensional effect and assuring an anatomic fit.
The extension in the linear elastic section should be linear at least up to 100% extension. This makes the garment able to easily stretch to at least twice the circumference, which makes it much easier to be donned.
To provide the necessary compression, it is preferred that the compression is between 1 mmHg and 40 mmHg. To be sure to avoid occurrence of abdominal compartment syndrome when the garment is used at a compression garment in the abdominal area, it is preferred that the compression is below 25 mmHg. To prevent hernia or wound rupture it is preferred that the compression is between 5 mmHg and 15 mmHg or even more preferred between 7 mmHg and 13 mmHg. Examples 1, 3 and 6 show calculations of compression in garments according to the invention. Example 6 provides the calculations showing the maximum compression to be below 25 mmHg even when a wrong size is used. When the right size is used the compression is between 5 and 13 mmHg at a strain of 10-30% in the supportive section and a strain of 20-100% in the elastic section.
All types of garments according to the invention comprise a circular knit tube.
In one aspect of the invention, the compression garment is in the shape of an undershirt. The undershirt preferably has comfort fabric in the upper part of the undershirt, as donning would be very hard if the entire garment were made from the compression providing material. To make donning easier, the garment comprises sections with easily stretchable fabric. The undershirt has a lower part providing compression and an upper part of easily stretchable fabric. The whole undershirt is preferably knitted in one process and there is preferably a seamless transition from the compression lower part to the easily stretchable upper part. With this design the undershirt can be donned more easily, especially by stepping into the garment and pulling it upwardly from beneath. Example 3 illustrates the compression as a result of wearing an undershirt according to this aspect of the invention. In another aspect of the invention the garment is in the shape of an abdominal binder. In a preferred embodiment, the binder is higher in the front than it is in the back. Examples 3 and 6 illustrate the elastic properties of the abdominal binder.
In one embodiment the abdominal binder comprises a closure mechanism, which could be any means of closure well known in the art including zippers, straps, VELCRO, hooks and loops, buttons, magnets as well as hooks and eyes. Disposable closing mechanisms such as e.g. adhesive tapes can also be used.
In the early stages after surgery, the wound needs to be examined and there is a risk of bleeding and infection. Thus, wearing a compression garment during this time requires that the wound be easily accessible. However, the movements required to remove conventional clothing will increase the risk that wound healing is affected and increases the risk of wound complications and rupture. Thus, in a preferred embodiment of the invention, the supportive section, or parts thereof, is removable. In a related embodiment, the supportive section, or parts thereof, is replaceable. This is desirable, for example, if the part should become contaminated e.g. by blood.
When the supportive section, or parts thereof, is replaceable, the tube portion of the compression garment may be used for a longer period of time and is both more economical, easier for the caregiver and more comfortable to the patient, as lifting or rolling the patient is avoided. It is preferred that the supportive section is attached to the compression garment by any means of closure mechanisms like the ones used in connection with the abdominal binder. A preferred example of such closures, or fixation components, is a hook and eye combination.
The supportive section (which may be the front section) may further comprise elastic straps at the upper and lower corners. These straps make the detachment and attachment of the section to the tube part easier, as they can be used as “handles”.
Another way of making detachment and attachment easier is to provide the abdominal binder with finger holes.
The garment may also be made in the shape of underpants or boxer briefs. The underpants or briefs may have comfort fabric in the lower part of the pants and the transition between the compression fabric and the comfort fabric may be seamless as it is described with the undershirt. The underpants may be worn alone or in combination with an undershirt or an abdominal binder, depending on the position and length of the incision.
Optimal hernia prevention may require wearing the undershirt and the underpants together.
In another embodiment the underpants may extend upwards towards the lower chest area. In a related embodiment, the underpants have an opening in the crotch region, allowing the user to go to the toilet without removing the garment in the incision area.
In another aspect of the invention the compression garment is in the form of an abdominal tube, which may be entirely seamless. The tube is like the binder except that the initial knitted seamless tube has not been cut and provided with the hook and loop closure. Otherwise the tube may be provided with the same supportive section as the binder. The tube may further be provided with easily extendible elastic trims with a silicon pattern on the side facing the skin of the user.
Examples 3 and 6 illustrate calculations of the compression in the abdominal tube.
A high level of comfort is obtained with the compression garment of the invention by a substantially seamless design. That is, the garment, or at least the tubular part thereof, is knitted in one-piece. When worn while lying down, it is uncomfortable to rest on seams.
A bodysuit design is also an option, and so are high underpants extending to the lower chest region.
It is preferred that the compression garment underpants have a similar seamless transition from compression fabric to easily stretchable fabric, e.g. between the body encircling portion to the legs of the underpants and the crotch area, in order to avoid excess pressure to these areas.
The present invention is appropriate for use in connection with a broad range of incision types. One kind of incision is a Caesarian section. Here, a suitable garment is in the form of pants with a transversely oriented, supportive section in one or the other side of the front of the pants. For patients with a midline Caesarean, the pants will have a longitudinally oriented, supportive section in the middle of the front.
Removal of the appendix can be made with an oblique incision. Here, an appropriate garment is in the form of an undershirt having a supportive section on the right hand side of the front covering the incision. The section may have an oblique orientation.
Many procedures that commonly are or were performed in open surgery can today be performed as laparoscopic surgery, which is a method by which surgery is done by making small incisions on the abdominal wall and inserting the instruments through specially designed ports. Laparoscopic surgery is commonly used for removal of the gall bladder, removal of the appendix, tubal ligation (sterilisation) and hernia repair (incisional and other). Here, a desired garment is in the form of an undershirt, possibly in combination with a pair of pants, where one or more square supportive sections cover the incisions. Such a garment can also be used after diagnostic laparoscopy.
In the typical use, especially early after surgery, the incision site is first covered with a wound dressing. This wound dressing will absorb exudates from the wound, and might even promote healing through suitable additives.
Another example is patients operated on because of abdominal aortic aneurysm (AAA). This type of surgery often involves a long midline incision and patients have a high risk of incisional hernia formation. Here, a compression garment is either an abdominal binder or a combination of underpants and undershirt, where a supportive section covers the whole incision.
The supportive section may have a ‘soft’ inner surface. In one preferred embodiment, the section is formed from a piece of so-called “spacer fabric”, which is a three layer fabric construction with a knitted inner side, a knitted outer side and pile yarns such as monofilament yarns forming pillars between the two sides. With this construction, the spacer fabric acts as a pressure distributing material and ensures an overall higher average compression compared to a garment made from compression fabric only.
In one embodiment of the present invention where the garment is a tube-like garment, the supportive section is built into the garment in the form of a front panel of such tube. In other embodiments of the invention, where the garment is an undershirt or underpants, the section is attached, i.e. sewn in, for example, on the inside of the front of the undershirt or underpants. This makes the supportive section non-visible, and makes the garment look essentially like normally underwear.
An important aspect in hernia prevention is that a garment for hernia prevention is to be used as soon as possible after the operation. This sets specific requirements relating to e.g. handling by health care personnel, monitoring of the compression level etc. The Abdominal binders according to the present invention can be worn essentially directly after surgery. Consequently, in one embodiment of the invention, the prevention regimen for hernia starts with a compression garment shaped as an abdominal binder.
In one embodiment the supportive section does not have hook and loops closure but is permanently attached to the tube portion, i.e. by sewing. Another embodiment is a tube-like garment with only one row of hooks and loops along one side of the supportive section. This enables opening and access to the wound, but not replacement of the supportive section separately.
The abdominal tube provides for support and compression, it is very simple and inexpensive to produce, has a compelling streamlined look but still features the protective supportive section.
The supportive section is preferably made of breathable material allowing the wound to heal. At the same time, the material is also preferably water permeable and/or vapor permeable and/or non-absorptive to wound liquids. The supportive section may further have transparent or semi-transparent properties for easy monitoring of the wound. In one embodiment this is achieved by using a mesh inner- or outer surface on the supportive section. This makes the garment useful as a medical bandage.
In order for the supportive section to cover the incision and effectively reduce shear forces on the incision/wound, it is preferable that the supportive section extends more than 1 cm beyond the wound region such as more than 2 cm wide, that is more than 3 cm, or 4 cm, or 5 cm or 6 cm or 7 cm or 8 cm, or 9 cm, or 10 cm, or even wider than 11 cm. This means that the width of the supportive section is at least 6 cm, more preferably at least 10 cm, maybe at least 15 cm or even at least 20 cm. Preferably the width is less than 40 cm and between 15 and 25 cm.
The supportive section may have any shape but is preferably of a shape similar to the wound region. In this way maximum comfort as well as proper protection of the wound is obtained. Whatever the size of the supportive section, it can be readily interchanged with a supportive section of any other size to provide a wide range of adjustability while retaining the same compression garment.
In a preferred embodiment the garment comprises a mechanism for measuring the elongation of the garment, preferably the radial elongation. As the elongation is substantially proportional to the compression obtained, elongation provides an effective monitoring tool for a nurse or the patient, as it is possible to read the compression of the garment. It is important to avoid a too high compression and to assure adequate compression. As the circumference around the abdomen can increase over a relatively short period of time due to, e.g., edema formation after surgery, this can result in an increase in compression. Providing the possibility to monitor the elongation, it is also possible to consider options as regards the increased compression, and one can, for example, choose to change the garment to a garment of a larger size and/or insert a larger non-stretchable part and thus reduce the compression accordingly. This is also an advantage in relation to patient weight gain/loss, or abdominal distension where a change in size of the garment may be appropriate.
Alternatively, if the garment is adjustable in size the monitoring of the elongation can be used for proper adjustment. In a particularly preferred embodiment the mechanism for measuring the elongation of the garment is an easily visible portion, i.e. a colored thread, knitted directly in the tubular item forming a line of a predetermined length, in a transverse direction relative to the tube. The formed line can, for example, be 10 cm long, when the garment lies flat on a plane surface. For example, an elongation to 14 cm (an increase of 40%) may indicate a level of compression recommended by the patient's doctor. A nurse or the patient himself may be provided with a sort of measuring device, such as a simple ruler, indicating the acceptable interval of compression when compared to the colored line in the garment, when the patient is wearing the garment.
When the garment is in the shape of a tube or a binder it is preferred that the garment has an easily extendible elastic trim. In a related embodiment the upper and/or lower part of the circular knit tube further includes silicon in a pattern so as to enhance friction between the garment and the skin under the elastic trim.
Another aspect of the invention relates to a method of preventing hernia or wound rupture for patients with an incision in the abdominal region with a compression garment comprising a circular knit tube with supportive sections (progressive elastic sections) and elastic sections forming a tube wall. The method includes:
The method of preventing hernia may also be known as a hernia prevention regimen.
In connection with a hernia prevention regimen it is of particular interest that the supportive section of the binder or tube is entirely detachable and thus it is possible to change only the part that covers the wound or incision. This part is most likely to become soiled by wound exudate so it may be necessary to change it more often than the rest of the binder or tube.
It may also be preferred to exchange one size of supportive section with another larger or smaller part thereby changing the compression in the garment. The changing of the supportive section may be done without removing the binder or tube, which is an advantage if the patient is temporarily immobilized.
The garment according to the invention is useful for prevention of hernia. Not only is it important to have external compression of the abdomen after abdominal surgery to reduce the incidence of incisional hernia, but in order that the preventive effect is obtained, the patient needs to wear the compression garment 24 hours a day for several months or even years. Interruptions during shower and change of garment are obviously needed. If user compliance is reduced, so is the preventive effect of the garment. To achieve high compliance the garment needs to be comfortable and to have a look that invites the patient to use it without looking like a patient. The preferred seamless knit tube is one aspect in providing comfort.
When the patient is mobilized, further needs arise. First of all, the patient is typically more mobile, for which reason the garment(s) for hernia prevention is preferably designed to allow the user to move around freely, including going to the toilet while the garment(s) stays in place. Discretion, comfort and ease of use are of particular importance. Thus, one embodiment relates to a regimen using a compression garment shaped as an undershirt.
In describing a preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.
For materials characteristics of the materials mentioned in the description of the figures, reference is made to example 2.
A material with progressive elastic properties is defined as a material having a non-constant and increasing MoE and where the MoE for higher extensions leaves the material section with a high resistance to further stretch or maybe even non-stretchable. For definitions of MoE used in this application, see example 1. This indicates that the material section would stretch relatively freely up to a certain level (the lower strain limit) after which further stretch will be virtually impossible. This is clear when compared to the extendibility of the elastic section, as described in the following, see
The front piece 30 can be connected to the elastic tube 20 by means of front closures 40. In the shown embodiment two row polyamide/polypropylene bands with covered metal eyes 41 are sewn together with the spacer fabric front piece. Corresponding polyamide/polypropylene bands with covered metal hooks 42 are sewn into the edges 39 of the elastic tube 20. In a preferred embodiment, a vertical separation of 2.5 cm between adjacent hooks on the band is chosen which is larger than usually employed but ensures that the closure remains closed during use but still is relatively fast to close. Including a vertically extending reinforcement element within the edges 43 of the front piece 30 could provide greater spacing.
The horizontal separation of the metal eyes is about 2 cm, providing a total adjustment of about 4 cm and wider separation distances could also provide for greater adjustment.
Closure components 41 are attached to both sides of the front piece. This provides the opportunity to access the wound from the most convenient side and to change the front piece without having to change the whole binder and thereby having to move or roll the patient over.
The upper and lower edges of the tube 20 and front piece 30 are provided with 25 mm wide, easily extendible elastic trims 50 with silicon dots or pattern on the side facing the skin of the user. Such silicon dots provide a comfortable and non-occlusive means of keeping the garment in place during use. In the embodiment shown in
To obtain a three-dimensional effect, assuring an anatomic fit, the tube is knitted with different zones 70-74 of varying stitch density. The back zone 70 of fabric variant C2 is the tighter structure, followed by transition zones 71, 72, towards the more elastic front zone 74 of fabric variant C1. Front zone 73 has an intermediate density providing support to the abdomen of the user.
The material and the different zones are characterized by their elastic properties, which can be measured by tensile testing as is well known in the art. Fabric samples as located in different zones are illustrated in
Finally, the binder is provided with a knitted-in coloured line 80 in a specific length, e.g., 10 cm. When the binder is in use, the elongation of the fabric can be read off directly from the elongation of the line. The measured elongation can then be combined with tensile test results as shown in
The lower part of the undershirt is made from material C with different zones 170-174 of varying elasticity and density similar to zones 70-74 of the abdominal binder. Zone 170 is made from fabric variant C2, and zone 174 is made from fabric variant C1, with other zones 171, 172, 173 being intermediate as discussed in connection with zones 71, 72, 73 of the abdominal binder. The undershirt is provided at the lower portion of the lower part 120 with an elastic trim 150 with silicon dots or pattern on the side facing the skin of the user, and a knitted-in colored line 180 for measurement of the fabric elongation.
The undershirt includes a seamless transition 190 from the low density, essentially easily stretchable, comfort fabric D of the upper part 110 to the dense and highly elastic compression fabric C of the lower part 120. The comfort fabric of the upper part 110 allows the undershirt to be donned from beneath, like a women's one-piece bathing suit. An undershirt made only from highly elastic compression fabric cannot be donned in any reasonable way without an opening mechanism such as a zipper, which is highly uncomfortable for the user and very hard to zip due to the compression power of the fabric.
The combination of an easily stretchable upper part 110 and a compression lower part 120 allows the undershirt to be easily donned and provides a look very close to normal underwear.
The front waistline 255 of the pants is positioned lower than the back waistline 256 and even lower than in normal underpants. This ensures that the pants will be placed below the stomach of a user. It may be an advantage as the stomach of the user, for newly operated patients, may be distended or swollen. When the pants 200 are used together with the undershirt 100 of
The pants are provided at the top end thereof with an elastic trim 250 with silicon dots or pattern on the side facing the skin of the user.
The front piece 330 can be connected to the elastic tube 320 by means of front closures 340. In the shown embodiment, a hook and loop system is used with a 38 mm wide hook material 341, such as male VELCRO, attached to the elastic compression material and a loop material 342, such as female VELCRO, attached to the supportive section or front piece 330.
The upper and lower edges of the tube 320 and front piece 330 are provided with 25 mm wide, easily extendible, elastic trims 350 with silicon dots or pattern on the side facing the skin of the user. Such silicon dots or pattern provide a comfortable and non-occlusive means of keeping the garment in place during use. In the embodiment shown in
To obtain a three-dimensional effect, assuring an anatomic fit, the tube is knitted with different zones 370, 371, 372, 374 of varying stitch density. The back zone 370 of fabric variant C2 is the tightest structure, followed by transition zones 371, 372 towards the more elastic front zone 374 of fabric variant C1.
The material and the different zones are characterized by their elastic properties, which can be measured by tensile testing as is well known in the art, see example 1.
Finally, the binder is provided with a knitted-in colored line 390 marking the centerline on the back of the binder. This feature is useful when the user is bed-ridden and health-care personnel apply the binder.
These figures discloses a binder allowing large adjustment in size, compression and fit by means of the hook and loop closure solution. There is no distinction between the upper and lower edges of the binder according to this embodiment, i.e., the binder can be worn with either edge “up”, enabling the hook and loop closure to be placed on the left or right part of the abdomen as the user wishes.
The binder can be opened and closed, and the size adjusted by means of front closures 440. In the shown embodiment a hook and loop system is used with a hook material (male Velcro) 441 attached to one end of the elastic compression material and a loop material 442 attached to the other end.
The upper and lower edges of the tube 410 are provided with 35 mm wide easily extendible elastic trims 450 with a silicon pattern on the side facing the skin of the user. Such a silicon pattern provides a comfortable and non-occlusive means of keeping the garment in place during use. In the embodiment shown in
This embodiment is made using only one stitch density (fabric variant C1) of the tube material 420. However, a three-dimensional effect can easily be obtained using different zones of varying stitch densities as described e.g. in the reference of
The tube material is characterized by its elastic properties, which can be measured by tensile testing as well known in the art, see example 1.
The binder is provided with a knitted-in colored line 495 marking the centerline on the front of the binder. This feature is useful when applying the binder ensuring that the substantially non-stretchable protective fabric is placed correctly over the incision, wound or dressing.
Finally, this binder is provided with finger holes made by cuts 492, 493 and stitches 494 in the loop material 442 as shown in
This binder allows large adjustment in size, compression and fit by means of the hook and loop closure solution. There is no up and down of the binder of this embodiment, hence, the hook and loop closure can be placed on the left or right part of the abdomen as the user wishes.
Instead of a binder a tube may be provided. The tube may be entirely seamless and is similar to the binder except for the hook and loop closure of the binder, which is lacking in the tube. Like the different binders, the tube is also provided with the supportive section made of fabric B (see example 2 for materials characteristic) sewn to the inside of the front of a knitted tube made of elastic compression material C. The tube is furthermore provided with easily extendible elastic trims with a silicon pattern on the side facing the skin of the user.
It is essential that the garment provide suitable compression. However, no consensus exists on how e.g. abdominal compression is defined and how it should be measured. The torso of most humans have a somewhat ellipsoidal shape which implies that the pressure provided by e.g. an abdominal binder varies around the torso according to the LaPlace equation. Hence, a distinction between local measurements made by, e.g., a probe, and overall materials characteristics is needed. In the following, guidance is provided as to how the elastic stress is measured and related to compression as defined here.
When an elastic material is stretched or elongated the material experiences an elastic stress. This elastic stress depends on the elongation and the fundamental properties of the elastic materials. It can be measured by standard mechanical tensile testing as is well known in the art.
Tensile testing is performed by applying a given force (F) to the material and measuring the elongation (Δx) of the material as illustrated in
The force and elongation measured depends on the size of the sample used for testing. For elastic fabrics (having a negligible thickness) one may define:
The elasticity of the fabrics may then be represented by either force-elongation curves or stress-strain curves. The systematic unit of force is Newton (N) and stress is in this case stated in N/m, N/cm or N/mm. Other units of force are also used as indicated in Table 1. Strain is usually given as either a percentage (%) or in pure numbers.
When stress is defined as force per width of sample, one may use the stress-strain relationship for linear-elastic materials for elastic fabrics as well
σ=E·ε
where σ is the stress and E is strain. Hence E, which usually denotes the modulus of elasticity (MoE), may represent an expression for the elasticity of the fabric, even though it is not a MoE in the normal sense. Accordingly, the MoE of elastic fabrics is in this case defined as the slope of the stress-strain curves, provided that the stress is defined as force per width of sample.
When an elastic material, such as a compression textile, is stretched across a curved surface a resulting inwardly directed force is obtained i.e. an overpressure or compression is generated. The compression (Δp) depends on the local radius (r) of curvature according to
where σ is the stress (N/mm) in the plane of the textile at a given elongation.
The fact that the compression generated by a compression textile depends on the local radius of curvature has important implications for the design of such textiles. Most people and hence patients have an abdominal, i.e. waist circumference, which is more ellipsoidal than circular in shape. The ellipsoidal character of the waist is more pronounced in people with a small waist, whereas people with a large waist tend to be more circular in profile. This implies that people wearing a compression textile covering the waist/abdomen will experience a higher compression on or above the hips, where the radius of curvature is small, compared to on the centre of the abdomen or on the back, where the radius of curvature is larger.
More specifically, if the waist circumference is described by an ellipsoid of semi-major axis a and semi-minor axis b, as common in the art, then the radius of curvature varies between rmin and rmax given by
The corresponding maximum compression (at the hips) is then
The minimum compression (around the midline of the abdomen or back) is
Finally, the average compression can be expressed approximately by
This corresponds to the compression of a circular profile having the same perimeter as the ellipsoid defined by semi axes a and b.
Thus, a compression garment is characterized by the elastic forces provided by the fabric used to manufacture the garment. The compression obtained when using various sizes of the garment on humans is illustrated in the following sections.
The systematic unit for pressure, and hence compression, is the Pascal (Pa=N/m2). However, traditionally other units such as mmHg are used.
As shown above estimation of the compression of a given abdominal compression textile depends on the size and waist profile of the user
For the further calculations a simple relationship between waist size and ellipsoidal a and b axes is assumed, which is illustrated in
An approximate expression for the relationship is the following, where w is the waist size in cm.
Material A: Spacer Fabric
Warp knitted spacer fabric
Construction: Double needle bar raschel fabric with a plain back side and a hole pattern on the front side (see-through).
Yarn: 100% Polyester, filament yarns and monofil pile yarn
Fabric Characteristics:
This fabric is an example of a virtually non-stretchable cushioning fabric.
Material B: Tricot Fabric, Mesh Fabric
Warp knitted fabric
Construction: Single needle bar warp knitted fabric with hole structure.
Yarn: 100% Polyamide, filament yarn
Fabric Characteristics:
This fabric is an example of a virtually non-stretchable thin fabric.
Material C: Santoni Compression Fabric
Bodysize Santoni SM 8-8 circular weft knitted fabric
Composition: Polyamide covered Elastane yarn, 50% Polyamide, 50% Elastane.
Knitting structure: Single pique 1-1.
Fabric Variant C1, Corsinel:
Fabric Characteristics:
Thickness: 1.09 mm (internal test method).
Stitch density: 1080 (cm−2), 60 courses per cm and 18 wales per cm.
Square meter weight 402 g/m2. (ISO 3801:1997).
Bulk density: 0.37 g/cm3 (calculated).
Fabric Variant C2:
Fabric Characteristics:
Thickness: 1.24 mm (internal test method).
Stitch density: 1320 (cm−2), 82 courses per cm and 16 wales per cm.
Square meter weight 493 g/m2. (ISO 3801:1997).
Bulk density: 0.40 g/cm3 (calculated).
C1 and C2 are examples of compression fabrics with high recovery “power”.
Material D: Santoni Comfort Fabric
Santoni circular weft knitted fabric, washed.
Composition: 97% Polyamide, 3% Elastane (3 yarns knitted together)
Knitting structure: Single mini jacquard
Fabric Characteristics:
This material is an example of an easily stretchable fabric.
Elastic properties of the materials were measured using British Standard BS 4952; 1992 using 50 mm wide samples. The results are provided in Table 3 below:
Non-stretchable fabric (A or B) shows an elongation at 2 kgf below 60% in both weft and warp directions.
A compression fabric (C1) is stretchable with an elongation at 2 kgf above 60% in both weft and warp directions but has a high recovery power defined as a force at 40% elongation above 0.2 kgf in both weft and warp directions.
Stretchable cushioning fabrics (D) shows an elongation at 2 kgf above 60% in both weft and warp directions and a force at 40% elongation below 0.2 kgf in both weft and warp directions.
Table 4 shows the composition of the compression garments, that is the pants, binder and tube.
In this example the supportive section is considered to be entirely non-stretchable in the calculations of the compression obtained.
The abdominal binder as shown in
Test samples 1-6, each having a size of about 75 mm×25 mm, were cut from an abdominal binder as indicated in
σ=0.1972·ε+0.0756
where σ is the stress in N/mm and is the elongation in absolute value. These measurements were made on small pieces of fabric cut from the actual binder and hence cannot be directly compared to the measurements of example 2 which were measured on large pieces of fabric made specifically for the test.
Compression in Abdominal Tube I
Consider an abdominal tube made wholly of compression fabric C1, hence
σ=0.1 972·ε+0.0756
It will be assumed that the user of the tube has an ellipsoidal waist profile with a=206.6 mm and b=111.7 mm. This corresponds to a waist perimeter of close to 1000 mm. If it is further assumed that the un-stretched tube has a waist perimeter of 625 mm, then the elongation is 60% when the tube is worn, and the elastic stress is 0.1939 N/mm according to the above expression. Using the assumptions and calculations shown in example 1, the following compression estimates may then be calculated:
Compression in Abdominal Tube II
Next considered is an abdominal tube similar to that of the previous section but provided with a 170 mm wide, non-stretchable supportive section. In this case the elastic part of the un-stretched textile has a width of 625 mm−170 mm=455 mm. When stretched, the elastic part has a width of 1000 mm−170 mm=830 mm; hence the elongation of the elastic textile is 82%. The stress in the fabric is then 0.2354 N/mm using the stress-strain expression. Compression estimates are:
It is clear that the tube with supportive section provides a higher compression than a similar tube made from compression fabric only. Hence, if a given compression is needed, the use of a supportive section allows the use of a more elastic textile material and/or a smaller elongation than that needed with a wholly elastic tube.
Compression in Abdominal Tube III
A calculation of the compression provided by the abdominal binder of
The table below provides calculated compression estimates for the abdominal binder of
Compression in Undershirt
The results of similar calculations relating to the undershirt of
An abdominal tube was made of compression fabric C with a stress-strain relationship of
σ=0.2156·ε+0.0869
as measured by tensile testing. The tube included a 170 mm wide, substantially non-stretchable, front piece made of material A. The tube had a total un-stretched waist size of 860 mm (elastic width 690 mm) and was mounted on a cylindrical plastic tube of 400 mm in diameter. The perimeter of the tube was 1256.6 mm, corresponding to an elongation of 57% of the elastic material. The calculated stress was 0.210 N/mm and the calculated compression was 7.8 mmHg everywhere (circular profile).
To test the calculation, a pressure sensor was inserted below the front piece of the abdominal tube between the abdominal binder and the plastic tube and the compression was measured directly. The equipment used was the I-SCAN® Lite Pressure Measurement System from Tekscan, Inc., 307 West First Street, South Boston, USA, comprising a type 5101 sensor in the form of a rectangular shaped matrix (112 mm×112 mm) forming squares and resulting in a 44×44 grid (1936 active measuring cells). Frames were captured, exported to a spreadsheet and averaged.
The measured compression in this case was approximately 7 mmHg, which is considered in good agreement with the calculated value.
The garments of the invention all comprise a knitted tubular compression section, which comprises an elastic section and a supportive section. In this example measurements on the linear elastic section (Corsinel or material C1, see example 2) as well as measurements of the supportive or progressive elastic section (layered material consisting of one layer of Corsinel, material C1 and one layer of mesh fabric, tricot fabric, material B, see example 2) were used as basis for the calculations. During the measurements the layered materials had the same size.
Test Setup
Force-elongation curves were obtained by tensile testing of test samples following BS 4952 1996, section 2.1.
Elastic Properties, Elastic Section
The linear functions appear from Table 10.
The Corsinel fabric is equal to the fabric C1, which was used in relation with example 3. The difference in the equations may be due to the difference in test set-up, e.g. sample size, measuring on second cycle as opposed to the first cycle and so forth.
The elastic section has linear-elastic material properties as defined in example 1.
Elastic Properties, Supportive Section.
The supportive section has progressive elastic material properties, which, as explained earlier, may have similar strain as the elastic section until a lower strain limit of about 20%. In one extreme situation the supportive section is entirely non-stretchable above the lower strain limit. In another extreme situation the supportive section has a higher elasticity above the lower strain limit as expressed by the definition of the MoE as illustrated in example 1. In the preferred embodiment the supportive section has an increasing elasticity as expressed by the definition of the MoE between the lower strain limit and an upper strain limit of about 40%, following which, the fabric becomes entirely non-stretchable.
One embodiment of making a material with progressive elastic material properties is to make a layered material with a first fabric layer of an elastic material and a second oversized layer of another material. The second oversized layer may be made of materials having an MoE which is much higher than the MoE of the first fabric, this would correspond to curve no. 2 in
Another embodiment of a material with changing properties is a material made of a fabric, which is completely un-stretchable but where the material is provided with a certain amount and size of holes. The holes will have the effect of making the fabric able to stretch relatively freely up to a limit where the holes are beginning to deform following which the MoE will increase as the holes are deforming. Finally the holes are completely deformed and the material will not be able to stretch further.
This kind of material may also be used as the second oversized layer in the layered material. In this case it will make a smooth transition over the lower strain limit while still provide the complete control at the upper strain limit due to the non-stretchability of the material occurring when the holes are completely deformed.
The polynomials appear from Table 11.
Elastic Properties of the Tube and Binder
The stress-strain relationship of the tube can be calculated combining the corresponding relationships for the elastic section and the supportive section. The force in the compression section must be same independent of whether the elastic section or the supportive section is considered. In the following we will disregard any effect of the waist elastic and simply assume that it follows the elastic or supportive section respectively, when they stretch. We will use the average (width/length) stress-strain curves (force application) to calculate the stresses in the Corsinel fabric, the elastic section and the layered structure, the supportive section, when the binder or tube is stretched.
The difference in strain in the supportive section and the elastic section is illustrated in
The total elongation may be found as the sum of the elongations of the separate sections, where each elongation is the strain times the length of the section. So the following conditions apply:
Felastic=Fsupportive
Δxtotal=Δxelastic+Δxsupportive
Δxsection=εsection·lsection
Using these conditions, it is possible to calculate numerically how a total elongation (strain) is distributed between the elastic section and the supportive section. The tube is assumed to have a total circumference of 71 cm (=710 mm) and a layered supportive section of a width of 27.6 cm (=276 mm) leaving an elastic section of 43.4 cm (=434 mm). One has to take into consideration that the supportive section may have linear elastic material properties until strain of 20% (0.2). Provided that the material within this limit (below strain of 20%) has properties like the elastic section corresponding to the Corsinel fabric, the stress at 20% is equal to 0.07 N/mm, see
Table 12 shows calculations of strain and elongations in the elastic section and the supportive section. Calculations of the total elongation in the tube are also illustrated.
By dividing the total elongation by the initial length of the binder (710 mm) it is possible to calculate a value for the total strain in the tube. The result of the calculations is shown in
Using the fitted polynomial curve of Table 11 and the linear regression of Table 10 it is possible to calculate the strain in the layered supportive section as a function of the overall strain.
Force-Compression Relationship
We will consider a simple one-dimensional model calculating the compression around the abdomen disregarding the effects of different heights of the garments. Assuming a given total circumference of the binder or tube, a given waist size of the user and using the waist profile relationship from
In case of the binder, one needs to take the hook and loop fabric into account; which account for between 3 and 10 cm of the circumference depending on how tight the binder is adjusted. The hook and loops fabrics are fully in-elastic, hence all elongation of the binder is distributed between the Corsinel fabric and the supportive front section.
Sizes of the Binder and Tube
The binder comes in two heights (low and high) and five sizes (XS, S, M, L, XL): Parameters (after wash at 80° C.) are given in Table 13.
The tube is identical to the binder except that the initial knitted seamless tube has not been cut and provided with the hook and loop closure. Otherwise the tube is provided with the same sandwich front and provided with easily extendible elastic trims with a silicon pattern on the side facing the skin of the user.
The tube comes in one height and five sizes (XS, S, M, L, XL): Parameters (after wash at 80° C.) are given in Table 14.
Compression
Table 15 provides the calculated average compressions for the tube, while Table 16 provides the calculated maximum and minimum compressions for the tube. The unit for the compression is mmHg.
The average compression varies between 0 and 22 mmHg, but if the sizing recommendations are followed, average compressions between 5 and 13 mmHg are obtained.
The average compression varies between 0 and 21 mmHg, but if the sizing recommendations are followed, average compressions between 5 and 12 mmHg are obtained.
The foregoing descriptions and drawings should be considered as illustrative only of the principles of the invention. The invention may be configured in a variety of shapes and sizes and is not limited by the dimensions of the preferred embodiment. Numerous applications of the present invention will readily occur to those skilled in the art. Therefore, it is not desired to limit the invention to the specific examples disclosed or the exact construction and operation shown and described. Rather, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| PA 2005 01731 | Dec 2005 | DK | national |
| PA 2005 01782 | Dec 2005 | DK | national |
| PA 2006 00207 | Feb 2006 | DK | national |
| PA2006 01098 | Aug 2006 | DK | national |
| PA 2006 01572 | Nov 2006 | DK | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DK2006/000690 | 12/5/2006 | WO | 00 | 1/7/2009 |
| Number | Date | Country | |
|---|---|---|---|
| 60789148 | Apr 2006 | US |
