Patent Description:
Brief Statement of the Prior Art Problems to be Addressed by the Present Invention Non-ambulatory patients suffering with minor illness or simple leg bone injuries, or the like, do not normally require the use of special purpose wheelchair cushions. However, in those long term care (LTC) cases where the patient suffers from serious postural injury or physical conditions involving pelvic or spinal related abnormalities expressing pelvic obliquity issues, anterior pelvic tilt issues, posterior and/or pelvic tilt issues, or pelvic rotation issues, the use of specially configured cushioning or other body positioning, orienting or supporting means may be required. The present invention is intended to address this need and to provide an adjustable wheelchair cushion that can be specified, prescribed and/or used by LTC therapists to improve the efficacy of wheelchair cushioning used in this environment. The following is included to provide background information relating to some of the postural abnormalities toward which the present invention is directed, and how an LTC therapist has sought to provide, or has in fact provided, patient relief during use of a standard wheelchair and cushioning means.

ASIS & PSIS at equal height: no pelvic tilt.

L ASIS & R ASIS at equal height: no obliquity.

L ASIS & R ASIS at equal depth: no rotation.

Spine balanced and upright; no rotation, no lateral curvature.

Normal lordosis in cervical and lumbar spine and normal kyphosis in thoracic spine creating the desired "S" shape. The head is functionally upright with only mild forward/lateral flexion or rotation.

When fitting an LTC user for a wheelchair, an LTC therapist will usually try to maintain proper patient postural alignment with a STANDARD cushion (and back support).

PELVIC OBLIQUITY - generally depicted in <FIG> of the Drawings.

In patients with this abnormality, the pelvis sits with the L or R ASIS higher than the other, causing the raising up of one hip. When one side of the pelvis is raised higher than the other, the thoracic spine curves away from the higher side creating a scoliosis over time.

The neck will go into lateral flexion as if the person is dropping an ear to his or her shoulder. The lateral flexion will usually be towards the side where the hip is higher.

Pressure redistribution is the therapist's support goal whether the deformity is FIXED or FLEXIBLE.

If FLEXIBLE: the pelvis should be leveled by building up the lower side.

If FIXED: the deformity should be accommodated by protecting the bony prominences from pressure by "filling in" the higher side and immersing the lower side IT.

With this abnormality, the pelvis sits with ASIS higher than the PSIS resulting in the posterior pelvic tilt which produces the sacral sitting posture. With excessive lordosis of the lumbar and cervical spine, the patient hyperextends his or her back over the sling back of the chair, placing him or her at risk to tip the chair backwards.

Excessive lordosis of cervical spine causes hyperextension of the neck and upward eye gaze. With this abnormality, the goal is normally to utilize a cushion and back support that maximizes contact with the seat surface for optimal pelvic and spinal stability and pressure redistribution. Stability is the goal, so a back support is normally used that is tall enough for the patient. Measurements are made from seat surface to the top of shoulder. A moldable back support to conform to the curvature of the spine is normally used.

With this abnormality, the pelvis sits with ASIS higher than the PSIS resulting in the posterior pelvic tilt which produces the sacral sitting posture. Excessive thoracic kyphosis, producing "C" shape spine, "flattening out" of the lordosis of the cervical spine and "flattening out" of the lordosis of the lumbar spine.

Decreased lordosis in cervical spine causes forward neck flexion & downward eye gaze to floor/lap. A cushion with medial and lateral contour is often used to promote LE alignment and pelvic stability. Appropriate cushion depth should be used to prevent the patient from sliding forward as he seeks reduced pressure behind the knees.

A rigid insert is often used to prevent hammocking of the seat and cushion and to keep the pelvis from collapsing into a posterior pelvic tilt.

If FLEXIBLE: A cushion with tapered adductors can be used to load the trochanters, stabilizing the pelvis in the resident's most neutral alignment.

If FLEXIBLE: A cushion with an anti-thrust component can be used to reduce forward sliding of the pelvis into posterior pelvic tilt.

If FIXED: An immersion style cushion that contours to the shape of the patient used to promote maximum pressure redistribution, minimizing peak pressures.

If FIXED: Opening seat-to-back angle in conjunction with a fixed tilt in the wheelchair is often used to match the patient's ROM limitations and minimize forward sliding.

Pelvis sits with L or R ASIS more forward than the other producing rotation in the hips.

The thoracic spine follows and rotates in the same direction as the pelvis. Therefore, if the right side of the pelvis is rotated more forward, the right side of the spine is rotated more forward as well. The neck will go into lateral flexion as if the person is dropping the ear to his or her shoulder.

In addressing this abnormality, the objective is to stabilize the pelvis in the patient's most neutral position - adjusting for flexible or fixed postures - to prevent further pelvic rotation. One option is to apply an anti-thrust force to reduce forward migration of the pelvis.

If FLEXIBLE: use tapered adductors and a medial abductor to create leg troughs for midline LE alignment and to maintain a pelvic neutral position.

If FIXED: use a cushion with less aggressive contouring. Protect the bony prominences with an immersion-style cushion.

<CIT> is an example of the background art. This document teaches a cushion having a shaped base on which is positioned a resilient, cushioning layer. The shaped base is constructed from a supportive foam and has front and lateral bolsters, The cushioning layer is an inflatable air cushion having a flexible base and an array of individual air cells arranged in rows across the flexible base.

An object of the present invention is to provide an adjustable wheelchair cushion apparatus that can be adapted to accommodate the particular anatomical support needs of a user having postural abnormalities.

Another object of the present invention is to provide an improved anatomical support cushion apparatus including at least one thermoplastic elastomer honeycomb cushion panel and a plurality of selectable inserts that serve to conform, support and/or stabilize a wide variety of wheelchair user sitting positions, user anatomies and disabilities.

Another object of the present invention is to provide an improved adjustable anatomical support cushion apparatus for providing pelvic and trunk stability for a wheelchair user having postural abnormalities.

Still another object of the present invention is to provide an adjustable anatomical support cushion apparatus for maximizing functional activities of daily living for a wheelchair user having postural abnormalities.

Yet another object of the present invention is to provide an improved anatomical support cushion apparatus for protecting skin and preventing wounds, and/or promoting the healing of existing wounds suffered by a wheelchair user having postural abnormalities.

A further object of the present invention is to provide an adjustable support cushion apparatus for maximizing comfort for a wheelchair user having postural abnormalities.

Another object of the present invention is to provide an adjustable anatomical support cushion apparatus for minimizing unwanted skeletal movement by a wheelchair user having postural abnormalities.

Yet another object of the present invention is to provide an adjustable support cushion for preventing progression of postural abnormalities.

A still further object of the present invention is to provide an adjustable anatomical support apparatus that is breathable to permit cooling of the user.

Another object of the present invention is to provide an adjustable anatomical support apparatus that can be tailored to create certain desired cushioning and stabilizing characteristics without having to introduce elements such as foam, fluids or other means which add cost or reduce durability.

Still another object of the present invention is to provide an adjustable anatomical support apparatus constructed of materials that are fast drying, and can be easily disinfected and sterilized by chemical wash, microwave treatment, detergent wash, or other means.

Briefly stated, the present invention is directed to an adjustable wheelchair seat cushion apparatus including a resilient thermoplastic honeycomb seat cushion member and a pivotally attached base member forming a planar base upon which the upper cushion member will rest when folded about the pivot to engage and lay thereupon. The base member may also be made of one or more layers of a more rigid thermoplastic honeycomb material. Positioned upon the base member and disposed between it and the overlying cushion member are user and/or LTC therapist installable, prescriptively sized and shaped pelvic obliquity elements, pommel elements and/or wedge elements operative to deform the cushion member when engaged therewith. Once the obliquity, pommel and/or wedge elements are positioned and affixed to the base member, the cushion member is rotated into engagement therewith and deformed thereby, and the assembly is inserted into its fabric cover, the zipper is retracted and the cushion-assembly is ready for use. In some cases, an ischial pad may also be inserted into a pocket provided in the back-center portion of the cover to protect the patient's ischial bone.

An important advantage of the present invention is that the thermoplastic elastomeric honeycomb material used in the construction of the apparatus is an anisotropic material having improved pressure relief, stability, compression set resistance, durability and low maintenance characteristics.

Another advantage of the present invention is that in fitting the cushion apparatus for a particular user, an LTC therapist may select from a wide variety of preformed shaping elements and cushion positions therefor to customize and individually tailor the cushion apparatus for an individual user.

Yet another advantage of the present invention is that a single size and shape of cushion can be matched with a variety of individually selectable, preformed shaping elements to support the specific requirements of a particular wheelchair user.

Still another advantage of the present invention is that the anatomical support apparatus may be constructed from a perforated core thermoplastic elastomer honeycomb panel that is breathable to allow perspiration removal and cooling of the apparatus user.

Another advantage of the present invention is that different thermoplastic elastomeric honeycomb core designs and/or multiple panels of different thermoplastic honeycomb core designs may be utilized to maximize design flexibility of the improved anatomical support apparatus.

Still another advantage of the present invention is that the thermoplastic elastomeric honeycomb core is fabricated from recyclable materials that are fast drying, and easily disinfected and sterilized.

These and other objects and advantages of the present invention will no doubt become apparent to those skilled in the art after having read the following detailed description of the preferred embodiments which are contained in and illustrated by the various drawing figures.

Referring now to <FIG> of the Drawings which, as pointed out above, depicts a conventional wheelchair <NUM> having disposed thereon a removable, improved anatomical support cushion <NUM>. As will be described in greater detail below, the cushion <NUM> is constructed of at least one flexible thermoplastic elastomer honeycomb core panel built in accordance with the present invention. It should also be noted that although the cushion assembly <NUM> is particularly well suited for wheelchair applications, the cushion assembly, or analogs thereof, may also be used in a variety of other anatomical support applications (e.g., mattresses, automobile and airline seats, arm rests, etc.).

<FIG> is provided to illustrate optimal user posture when seated in a standard wheelchair.

<FIG> are provided to respectively illustrate postural conditions identified as pelvic obliquity, anterior pelvic tilt, posterior pelvic tilt and pelvic rotation; all are conditions that can be aided through use of the present invention.

<FIG> generally depicts the principal components of an adjustable wheelchair seat cushion apparatus <NUM> including a multi-layered resilient thermoplastic honeycomb seat cushion member <NUM> and a pivotally attached base member <NUM> forming a planar base upon which the upper cushion member <NUM> will rest when folded about the pivot <NUM> to engage and lay thereupon. The base member <NUM> may also be made of one or more layers of a more rigid thermoplastic honeycomb material. Positioned upon the base member <NUM> and disposed between it and the overlying cushion member <NUM> are user and/or LTC therapist installable, prescriptively sized and shaped pelvic obliquity elements <NUM>, pommel elements <NUM> and/or wedge elements <NUM> operative to deform the cushion member <NUM> when engaged therewith. Once the obliquity, pommel and/or wedge elements are positioned and affixed to the base member <NUM>, the cushion member <NUM> is rotated into engagement therewith and deformed thereby, and the assembly is inserted into its fabric cover <NUM>, (<FIG>), the cover zipper <NUM> (<FIG>) is retracted and the cushion assembly is ready for use. In some cases, an ischial pad <NUM> may also be inserted into a pocket <NUM> provided in the back-center portion of the cover <NUM> to protect the patient's ischial bone.

<FIG> illustrates a multi-layered honeycomb panel structure constructed from thermoplastic elastomer materials. The panels include a honeycomb-like core preferably made of bonded together and expanded strips or ribbons of plastic material to which facing sheets of perhaps heavier gauge material are thermo-compression bonded. The illustrated cover member <NUM> is an anisotropic three-dimensional structure having predetermined degrees of flex along the X, Y and Z axes. Each cell is formed, in part, by four generally S-shaped wall segments each of which is bonded to and shared by an adjacent cell. In addition, each cell shares a double thickness wall segment with two adjacent cells.

Panel <NUM> has high tear and tensile strength and is highly resilient, with optimal compression load and shock absorption or distortion characteristics, yet is extremely light weight. Selected combinations of elastomer material, honeycomb cell configurations, core thicknesses and facing material variables will determine the panel's characteristics of softness or hardness, resilient recovery rate and rigidity or flex as required for a particular application. The facing materials can be selected from a wide variety of films, including thermoplastic urethanes, foams, EVAs, rubber, neoprene, elastomer impregnated fibers and various fabrics, etc. The manufacturing and fabrication of the panel14 is described in greater detail in our <CIT>.

More specifically, the present invention relates to an adjustable seat cushion assembly including an upper component preferably made of multiple layers of resilient thermoplastic honeycomb material, shaped and bonded together to form a user supporting cushion member, and a generally planer lower component preferably made of at least one relatively thin sheet of more rigid honeycomb material, and having an edge thereof hingedly connected to the cushion member, preferably along it's rearmost extremity. The lower component is adapted to form a relatively rigid base member upon which the overlying cushion member will be supported when folded about the hinged connection to lie thereover. Removably disposed between the base member and the cushion member, and preferably attached to the upper surface of the base member at predefined locations, are one or more cushion deforming elements selected to define the user support characteristics of the cushion assembly.

With the upper cushion member rotated upwardly relative to the base member, the upper surface of the base member forms a supporting surface for an assortment of prescriptively sized and shaped pelvic obliquity elements, pommel elements and/or wedge elements.

These elements are selected, positioned and secured by the user and/or assisting therapist or clinician on the upwardly facing base member surface so as to deform the overlying resilient cushion member to support, raise, align, orient or otherwise adjust the user's skeletal components supported by the cushion assembly to provide pelvic and trunk stability, maximize the user's comfort and function during ADLs, protect the user's skin and prevent wounds, or assist in the healing of existing wounds, minimize unwanted movement of the user on the cushion surface, correct or accommodate postural abnormalities and/or prevent or mediate progression of postural abnormalities.

As will be further described below, these elements are adapted to deform the cushion member as it is lowered (folded down) into supporting engagement therewith. The preformed obliquity elements, pommels_and wedges are carefully selected and positioned to provide a desired customizing deformation of the overlying cushion member so that the cushion provides the supporting needs of the user when the assembly is folded into its closed, or folded, configuration.

Once folded, the cushion assembly is inserted into an enveloping fabric cover that is configured to conform to the shape of the cushion assembly and is provided with perimeter zippering means, or the like, to securely house the cushion assembly and maintain it in its closed and functional configuration. The cover may also be provided with internal and/or external pockets for receiving additional ischial pads, pommels or wedges, etc..

In <FIG> a multi-layered cushion member embodiment, the details of which are more fully disclosed in Applicant's <CIT>, is shown modified to include a lower flap or base member as described above to more clearly illustrate attachment of the flap edge by thermocompression bonding along the rear side of the upper cushion. Alternatively, the flap edge may be otherwise attached to the upper cushion member.

In <FIG>, side views of the above described cushion assembly are shown in more detail.

In <FIG> a frontal view is depicted and in in <FIG>, a partially broken side view is shown further illustrating the cushion assembly disposed within its fabric cover.

Note that a closing zipper is provided around three sides of the lower edge of the cover, and a second, medially disposed expansion zipper and excess material facility_is suggested to accommodate an assembly of larger cushion deforming elements should that be necessary.

Claim 1:
An adjustable anatomical support and seat cushion assembly (<NUM>) for wheelchairs (<NUM>) comprising:
a generally rectangular, resilient seat cushion member (<NUM>) and a generally rectangular, planar base member (<NUM>),
characterized in that
the seat cushion member (<NUM>) is formed of a plurality of layers of thermoplastic honeycomb material;
the planar base member (<NUM>) is formed of at least one layer of a thermoplastic honeycomb material, the base member (<NUM>) being disposed beneath the seat cushion member (<NUM>) and having a rear edge (<NUM>) thereof pivotally attached to a corresponding rear edge of the seat cushion member (<NUM>) at a hinge, the base member (<NUM>) being rotatable between a non-parallel disposition relative to the seat cushion member (<NUM>), and a parallel disposition relative to the seat cushion member (<NUM>); and the adjustable anatomical support and seat cushion assembly (<NUM>) for wheelchairs (<NUM>) further comprises:
a plurality of prescriptively sized and shaped pelvic obliquity elements (<NUM>), pommel elements (<NUM>) and/or wedge elements (<NUM>) affixed to a surface of the base member (<NUM>) generally facing the seat cushion member (<NUM>), the pelvic obliquity elements (<NUM>), pommel elements (<NUM>) and/or wedge elements (<NUM>) being operative to engage and deform the seat cushion member (<NUM>) when the base member (<NUM>) is rotated from the non-parallel disposition relative to the seat cushion member (<NUM>) into the parallel disposition relative to the seat cushion member (<NUM>), the plurality of prescriptively sized and shaped pelvic obliquity elements (<NUM>), pommel elements (<NUM>) and/or wedge elements (<NUM>) being removable from the base member (<NUM>).