Patent Issued for Passage-defining prosthetic limb structure and fabrication method (USPTO 11291563): Arizona State University

2022 APR 25 (NewsRx) -- By a News Reporter-Staff News Editor at Insurance Daily News -- A patent by the inventors LaBelle, Jeffrey (Tempe, AZ, US), Mason, Courtney (Chandler, AZ, US), filed on March 2, 2020, was published online on April 5, 2022, according to news reporting originating from Alexandria, Virginia, by NewsRx correspondents.

Patent number 11291563 is assigned to Arizona State University (Scottsdale, Arizona, United States).

The following quote was obtained by the news editors from the background information supplied by the inventors: “In the United States, about two million people have lost a limb, with hospital costs for amputations of approximately $8.3 billion each year. It is estimated that the total number of lower limb amputees in the United States is about 1.46 million, with the number of transtibial or below-the-knee amputees growing by about 185,000 per year. 54% of limb losses are attributable to vascular diseases, including diabetes and peripheral arterial disease; about 45% of limb losses are attributable to physical trauma; and fewer than 2% of limb losses are attributable to cancer, with a ratio of upper limb to lower limb loss of 1:4. Prosthetics can cost up to $50,000 per limb, and a significant number (possibly a majority) are not covered by insurance. Additionally, many prosthetics need to be replaced as the user grows, and health insurance frequently does not cover the cost of continual replacement.

“Current state of the art designs for below the knee (BTK) prosthetics features a simple titanium post for the load bearing portion of the prosthetic. FIG. 1 shows a conventional prosthetic leg 101 having a socket 121 with a recessed surface arranged to engage an end of a user’s amputated limb (e.g., remaining leg portion). The socket 121 may embody a padded plastic structure that distributes compressive forces on the end of the amputated limb. The bottom of the socket 121 is attached to a pylon 123 which may embody a tubular metal (e.g., titanium) support. The bottom of the pylon 123 may attach to an artificial foot 125 that can be a molded plastic structure. The prosthetic leg 101 may include a foam covering 127 that can be attached to the socket 121 and the pylon 123 to provide a more lifelike shape. Components of the prosthetic leg 101 can be coupled together using fasteners such as screws, bolts, and adhesives.

“Current BTK prosthetic designs can be uncomfortable for patients. Typically, patients most frequently report that discomfort emanates from the socket. However, there is a source of discomfort that patients might not link to their prosthetic or simply attribute it to prosthetic use. Titanium pylons may be too strong and rigid for gait impact while using the prosthetic. Although light and easily manufactured, a typical pylon doesn’t yield at all on impact and can send shock forces up the stump, through the thigh, and can affect the hip and back. Typically, such forces are softened by the ankle pad and lower limb joints, but amputees lack such cushioning, and the knee joint not only is under new stresses from the socket but also takes more shock due to the lack of padding. Additionally, BTK prosthetics users have asymmetrical and compensatory gaits due to the loss of the ankle plantar flexors, which can further aggravate the effects of the pylon. While this is a concern for amputee athletes, it can also cause problems with overweight amputees (which make up a significant portion of BTK amputees due to Type II Diabetes). Any patient with a BTK amputation therefore could experience these issues.

“Currently, shock absorbing pylons include spring-like mechanisms so the pylon shortens with axial loads. At best, the effectiveness of shock absorbing pylons is inconsistent; at worst, they have no effect. This may be attributable in part to the fact that during heel strike, the load is not axial, since the leg is at a non-vertical angle when ground contact is made.

“Functional prosthetics include categories of body-powered and externally-powered prosthetics. Body-powered prosthetics typically use cables and harnesses strapped to the individual to mechanically maneuver the artificial limb, but can be fatiguing to operate. Externally powered artificial limbs, including myoelectric prosthetics, seek to reduce user fatigue using batteries and electronic systems to control movement. A myoelectric prosthetic may be attached to a user’s remaining limb portion using suction technology or other means, and sensors may be used to detect minute muscle, nerve, and electromyographic activity. Muscle activity triggered by a user is translated into information used by electric motors to control movement of the artificial limb. Myoelectric limbs may look and even move much like a natural limb. The primary disadvantages to such limbs are weight and cost. Moreover, endoskeletal designs leave limited room for other prosthetic components.

“Prosthetics with endoskeletal structures or exoskeletal structures are known. Endoskeletal prosthetics include at least one internal support, such as an aluminum, titanium, or carbon fiber pylon. Exoskeletal prosthetics include an outer structure providing structural rigidity, typically including laminated reinforcement materials such as fiberglass, nylon, Dacron®, carbon fiber, and Kevlar®, which may be bound with polymer resin. Depending on the skeletal structure, providing sufficient space and convenient passage for actuating components can present challenges. It can also be challenging to tailor the size, shape, and appearance of a prosthetic to match a remaining limb of a user in a rapid and cost-effective manner.

“Due to their custom character and potentially high complexity, prosthetic devices typically require significant manufacturing time and entail high production costs. Need exists for prosthetic devices and prosthetic device fabrication methods to address limitations of conventional devices and methods.”

In addition to the background information obtained for this patent, NewsRx journalists also obtained the inventors’ summary information for this patent: “In certain aspects, a prosthetic device includes an internal frame assembled from multiple longitudinal members and multiple transverse members, wherein each member is substantially planar and defines peripheral slots therethrough, and wherein the longitudinal members and transverse members are arranged to mate with one another to join the longitudinal members with the transverse members. Each transverse member defines a medially arranged opening, and the medially arranged opening of each transverse member is substantially registered with the medially arranged opening of at least one adjacent transverse member. At least some transverse members of the plurality of transverse members differ from other transverse members of the plurality of transverse members in one or more of shape, length, or width. Longitudinal and transverse members of various materials may be used to produce lightweight and crush-resistant prosthetic device structures capable of withstanding substantial axial and torsional loads.

“Substantially planar longitudinal members and transverse members can be fabricated using various materials and various fabrication techniques. Examples of materials that may be used according to certain embodiments include, but are not limited to, the following: polymeric materials, fiber-reinforced materials, composites, laminated composites, multi-layer laminates, carbon fiber, paperboard, wood-based materials, fiberglass, metals, metallic materials, and combinations of two or more of the foregoing. Examples of techniques that may be used to produce longitudinal members and transverse members include, but are not limited to, the following: thermoforming, molding, stamping, forging, casting, milling, blade cutting, laser cutting, liquid jet cutting, three-dimensional printing, multi-layer additive material deposition, and combinations of two or more of the foregoing.

“The term “substantially planar” as used herein refers to an element preferably having length and width dimensions that substantially exceed a thickness dimension, wherein at least one face is preferably substantially flat in character. In certain embodiments, length and/or width dimensions of substantially planar members disclosed herein each exceed corresponding thickness dimensions by a factor of at least five, at least ten, at least fifteen, at least twenty, at least thirty, at least forty, at least fifty, at least seventy-five, or at least one hundred.

“In certain embodiments, at least some transverse members (or all transverse members) may be arranged along planes substantially parallel to one another.

“In certain embodiments, at least some transverse members, at least two transverse members, or all transverse members, may be arranged substantially perpendicular to longitudinal members with which the transverse members are assembled.”

The claims supplied by the inventors are:

“1. A prosthetic device sized and shaped to correspond to at least a portion of a limb of a human user, the prosthetic device comprising: an internal frame that comprises: a plurality of longitudinal members, wherein each longitudinal member of the plurality of longitudinal members is substantially planar and comprises a plurality of first peripheral slots defined through an entire thickness of the respective longitudinal member; and a plurality of transverse members, wherein each transverse member of the plurality of transverse members is substantially planar and comprises a plurality of second peripheral slots defined through an entire thickness of the respective transverse member; wherein each first peripheral slot of the plurality of first peripheral slots is arranged to mate with a different second peripheral slot of the plurality of second peripheral slots, to join the plurality of longitudinal members with the plurality of transverse members; wherein each transverse member defines a medially arranged opening, and the medially arranged opening of each transverse member is substantially registered with the medially arranged opening of at least one adjacent transverse member; and wherein at least some transverse members of the plurality of transverse members differ from other transverse members of the plurality of transverse members in one or more of shape, length, or width.

“2. The prosthetic device of claim 1, wherein the plurality of longitudinal members is devoid of any longitudinal members that are radially arranged relative to a central axis extending through the plurality of transverse members.

“3. The prosthetic device of claim 2, wherein longitudinal members of the plurality of longitudinal members are tangentially arranged relative to an imaginary circle concentrically arranged with the central axis, wherein the imaginary circle comprises a diameter smaller than a lateral extent of each transverse member of the plurality of transverse members.

“4. The prosthetic device of claim 1, further comprising at least one of an actuator or a control element extending through medially arranged openings of multiple transverse members of the plurality of transverse members.

“5. The prosthetic device of claim 1, wherein two or more transverse members of the plurality of transverse members each define a peripheral recess, wherein for each transverse member of the two or more transverse members, at least two peripheral slots of the plurality of second peripheral slots extend from the peripheral recess into an interior of the transverse member without intersecting the medially arranged opening.

“6. The prosthetic device of claim 5, wherein the peripheral recess of each transverse member of the two or more transverse members is registered with the peripheral recess of each other transverse member of the two or more transverse members.

“7. The prosthetic device of claim 1, wherein two or more transverse members of the plurality of transverse members each define a peripheral recess, wherein the peripheral recess of each transverse member of the two or more transverse members is registered with the peripheral recess of each other transverse member of the two or more transverse members.

“8. The prosthetic device of claim 7, further comprising at least one of an actuator, an energy storage element, a sensor, or a control element arranged in the peripherally arranged recesses of the two or more transverse members.

“9. The prosthetic device of claim 1, further comprising an outer shaping member arranged to cover and compressively engage at least a portion of the internal frame.

“10. The prosthetic device of claim 1, wherein at least two transverse members of the plurality of transverse members are arranged substantially perpendicular to the plurality of longitudinal members.

“11. The prosthetic device of claim 1, wherein the plurality of transverse members is bonded to the plurality of longitudinal members.

“12. The prosthetic device of claim 1, wherein at least some members of at least one of (i) the plurality of longitudinal members or (ii) the plurality of transverse members comprises polymeric materials.

“13. The prosthetic device of claim 1, wherein at least some members of at least one of (i) the plurality of longitudinal members or (ii) the plurality of transverse members comprises paperboard materials, wood fiber-based materials, or laminated composite materials.

“14. The prosthetic device of claim 1, wherein at least some members of at least one of (i) the plurality of longitudinal members or (ii) the plurality of transverse members comprises metals or metallic materials.

“15. The prosthetic device of claim 1, wherein the plurality of longitudinal members consists of four longitudinal members.

“16. The prosthetic device of claim 1, further comprising a socket positioned at an upper end of the internal frame, wherein the socket is configured to receive a residual limb of the human user.

“17. A method for fabricating a prosthetic device according to claim 1, the method comprising mating each first peripheral slot of the plurality of first peripheral slots with a different second peripheral slot of the plurality of second peripheral slots to join the plurality of substantially planar longitudinal members with the plurality of substantially planar transverse members to form the internal frame of the prosthetic device.

“18. The method of claim 17, further comprising bonding at least some transverse members of the plurality of substantially planar transverse members to the plurality of substantially planar longitudinal members.

“19. The method of claim 17, further comprising providing an outer shaping member to cover at least a portion of the internal frame.

“20. The method of claim 17, further comprising measuring one or more dimensions of a prosthetic recipient, and fabricating (i) the plurality of substantially planar longitudinal members and/or (ii) the plurality of substantially planar transverse members responsive to said measuring.

“21. The method of claim 17, further comprising fabricating at least some members of (i) the plurality of substantially planar longitudinal members and/or (ii) the plurality of substantially planar transverse members by at least one step selected from thermoforming, molding, stamping, or casting.

“22. The method of claim 17, further comprising fabricating at least some members of (i) the plurality of substantially planar longitudinal members and/or (ii) the plurality of substantially planar transverse members by at least one step selected from milling, blade cutting, laser cutting, or liquid jet cutting.

“23. The method of claim 17, further comprising fabricating at least some members of (i) the plurality of substantially planar longitudinal members and/or (ii) the plurality of substantially planar transverse members by at least one step selected from three-dimensional printing or multi-layer additive material deposition.”

URL and more information on this patent, see: LaBelle, Jeffrey. Passage-defining prosthetic limb structure and fabrication method. U.S. Patent Number 11291563, filed March 2, 2020, and published online on April 5, 2022. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=11291563.PN.&OS=PN/11291563RS=PN/11291563

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