Therapeutic stump treating air sac prosthesis

Abstract

A prosthesis is provided in which an amputative leg stump is surrounded by an air sac surrounded by a casing which confines the pressure of the air sac inwardly against the stump. Means are provided for supporting the distal end of the air sac around and beneath the patient's stump. Protuberances are provided between the air sac and the casing, distorting the surface of the air sac and giving it vertical stability with respect to the supporting means.

Description

BRIEF DESCRIPTION OF THE INVENTION

This invention relates to a prosthetic device for an amputative limb, particularly, an amputative leg stump. It relates particularly to the provision of a prosthetic device which may be used immediately in the post operative phase following surgical amputation.

BRIEF DESCRIPTION OF THE PRIOR ART

In recent years, many advantages have been obtained by the use of a temporary prosthetic fitting in the rehabilitation of patients in the immediate post operative period. However, known techniques such as the use of rigid plastic sockets and the like have resulted in severe pain, stump damage and various other difficulties, all of which severely interfere with the physical and mental recovery of the patient from the trauma of the amputation procedure.

Various devices have been created in an effort to bring about early ambulation, overcome problems such as stump damage, collection of edema in the area, and pain and discomfort to the patient during the period of use of the prosthetic device. For example, J. M. Little, in Med. J. Aust. 1972, 1:1300-1302 describes the combination of a rigid frame with a pneumatic prosthesis, which is described as being useful in connection with lower-limb prosthesis, and which is capable of modification for use by above-knee amputees. In such case a webbing harness is provided, running over the patient's shoulders and attached to the metal frame of the prosthesis.

It has been my experience, however, with prosthesis of this type, that serious difficulties have been encountered in actual use. For example, I have found that when the distal end of the stump is unsupported a "mushrooming" effect occurs in which edema collects at the distal end, with resulting extreme discomfort to the patient, and with interference with the orderly procedure of the rehabilitation process. Further, the air sac has been subject to accidental deflation by contact with sharp objects, cigarettes or the like, with near-catastrophic results with respect to the post-operative stump. All of these factors have tended toward enforced bed rest during the immediate post-operative period.

Post-operative edema is a serious problem which almost always occurs after amputation. Further, the trauma afforded to the extremity by surgery causes a subsequent stasis of blood in veins and capillaries, and tends to create a clotting situation in the veins which is referred to as phlebothrombosis. This is a serious condition and may have serious consequences; the clot may break loose and pass on to the heart or to the lung causing a pulmonary infarct, which may result in sudden death. Further, if clotting remains in veins in the post amputative area, the clots seriously interfere with the return circulation of the body fluids of the stump to the heart, thus producing a condition of edema with venous insufficiency. Should the clotting occur in the arteries of the stump, then a condition of vascular arterial insufficiency occurs, which results in an inadequate blood supply to the stump, with resultant poor healing or failure to heal. This may cause a gangrenous condition of the stump, sometimes requiring re-amputation at a higher level. This possibility subjects the patient to double jeopardy with respect to his life, and to the trauma of the subsequent amputation.

Other complications, in addition to the failure to obtain rapid and proper healing of the incision, include the lack of absorbtion of the extra vasated blood and other waste materials which necessarily follow surgery and are not removed by a surgical drain or the like. Still another complication is the development of contracture of the joint above the situs of the amputation, due to a lack of immediate mobility of the stump.

Other complications that may occur when there is lack of immediate mobility of the stump include decreased metabolism, development of thrombotic phenomenon in the extremity which has not been operated upon, as well as in the stump, with resultant jeopardy of limb and life, respiratory problems, possible development of decubitus ulcers due to the pressure of the body against bony prominences -- further complicating the rehabilitation of the patient, and various psychological effects.

Among the sequelae may be mentioned the organization of extravasated blood into dense, fibrous connective tissue resulting in hard tumorous masses which interfere with the fitting of a permanent prosthesis, even after several weeks or months of healing time. These fibrous collections are frequently painful in themselves and also cause pain by exerting pressure on adjoining structures such as nerves, bones, etc. This may further jeopardize the patient by subjecting him to further surgical intervention. Further, the development of smaller fibrous whorls results in pain to the patient and may result in inadequate circulation.

It is, of course, of critiical importance that the post-amputative healing must be such as to produce a stump that is pain free so that it may be fitted for permanent prosthesis. Many of the post-amputative patients are quite elderly, or quite ill, and are so weak that they cannot walk with one leg and with crutches after amputation. The supplemental support of a lightweight, temporary prosthesis, on which the patient can bear weight, can make a critical difference between ambulation or bed-chair confinement, with all attendant complications. It is especially important to provide a prosthesis which is light enough in weight to permit weakened patients to ambulate.

OBJECTS OF THE INVENTION

It is accordingly an object of this invention to provide a temporary prosthetic device, usable in connection with post-amputative patients, which not only eases the rehabilitation procedure but also provides beneficial manipulation of the post-amputative member.

Another object is to provide a temporary prosthesis which may be used by weakened patients in the immediate post-operative period and which significantly contributes to post-amputative healing.

A further object of this invention is to provide such a device which is strong, lightweight, inexpensive, easy to use and which is readily adaptable to various lengths, sizes, types and configurations of amputative stumps.

Still another object of this invention is to provide such a device which is easily applied and removed, making it possible to inspect the stump at any time.

Other objects and advantages of this invention will further become apparent hereinafter, and in the drawings.

DRAWINGS

Of the drawings, FIG. 1 is a view in section, showing one particular form of prosthetic device embodying features of this invention, and

FIG. 2 is a sectional view taken as indicated by the lines and arrows II--II which appear in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Although the following description will employ specific terms for the sake of clarity and for convenience in referring to the specific embodiment of the invention selected for illustration in the drawings, it will be appreciated that these terms, and the specific form illustrated in the drawings, are not intended to limit the scope of the invention, which is defined in the appended claims.

Referring to FIG. 1, the letter S designates the post-amputative stump, which is surrounded as shown in the drawings, by an air sac 10 which has an inner wall 11 and an outer wall 12. The casing 13, of fiberglass or the like, is shown as being reinforced by vertical internal ribs 14 and by rings 15 which may be circular in shape as shown in FIG. 2.

The number 16 designates straps, secured to the casing 13, and suspended across beneath the distal end of the air sac 10, immediately beneath such distal end. Accordingly, the straps 16 form a web extending in several directions across the prosthetic device, immediately beneath the end of the patient's stump and the lower ends of the air sac 10.

The ribs 14 curve inwardly at 20 and converge to join with a support 17, which is connected slidably and telescopically to another support 18 which in turn is affixed to a solid ankle cushion heel type foot 21. The foot 21 is also sometimes referred to as an "SACH" foot, as is well known in the art. The number 22 designates an adjustment screw device, conveniently arranged for adjusting the length of the prosthetic device, and for adjusting the direction of the foot.

It is important in accordance with this invention that the air sac 10 is substantially completely surrounded, as shown in FIG. 2, by the rigid casing 13. The casing 13 rigidly confines the outermost portions of the air sac 10, preventing them from yielding outwardly, or "ballooning" in a manner to impede the effectiveness of the air sac in maintaining, supporting and centering the stump S in position with respect to the supporting structure of the prosthetic device.

It is also important in accordance with this invention that a plurality of rings or protuberances 23 are provided, shown in the drawing as rings running in a complete circle around the inside of the casing 13, such rings being spaced apart from each other longitudinally with respect to the prosthetic device. As will be observed from the drawings, these protuberances or rings project toward the casing of the air sac 10, displacing it inwardly, thus providing vertical stability of the air sac 10 with respect to the casing 13, the ribs 14, and the supports 17 and 18 and the SACH foot 21. This is an important and advantageous feature of the invention, since otherwise considerable vertical slippage has been encountered, between the air sac 10 and the casing 13, in the actual use of the device.

It is a further important feature of this invention that the webbing or straps 16, or equivalent devices, are provided immediately beneath the distal end of the air sac 10. This is particularly true in the case of a preferred form of air sac, as shown in the drawings, having an annular distal end 24, 24. The webbing 16, in the normal use of the prosthetic device, exerts a force upwardly against the distal end 24, 24, in the direction indicated by the arrows f, f, providing active support for the distal end of the air sac, which in turn reinforces the active nature of the further forces f', f' between the distal end of the air sac 10 and the end of the amputative stump S. This is a most important and advantageous feature of this invention, since otherwise there is severe danger of the so-called "mushrooming" effect, whereby edema has been found to develop and to accumulate in the distal end of the stump S. The webbing 16 is also a protective device in the case of sudden deflation of air sac 10, and prevents catastrophic damage to the stump S.

It will be appreciated that a wide variety of changes may be made without departing from the scope of the invention by substituting various other active shock absorbing supports in place of the webs or straps 16, provided such supporting means exerts an active force upwardly on the distal end of the air sac 10. For example, the space beneath the distal end 24, 24 may be filled with straw, foam rubber or other resilient supporting material which is capable of exerting an active force upwardly in the manner of the forces f, f. As another example, a spring loaded device such as a dashpot or the like may be used, preferably having a padded surface for the absorbtion of shock in the event that the pressure should accidentally be lost in the air sac 10.

It will be observed that the air sac 10 has an air valve 25 through which air can be conveniently introduced or released, in order to fill or to empty the air sac or to adjust the air pressure to a desirable level.

It has been discovered that the provision of an air sac 10 having an annular, sealed distal end 24, 24 is of great advantage. It can, of course, be applied very easily around the amputative stump. It may, indeed, be stored in a flat, sheet-like manner when it is not inflated, and may be wrapped gently around the amputative stump S and then secured as by a longitudinal zipper or the like, in the desired position. It may then be inserted into the casing 13 in the correct position with the distal end 24, 24 wholly or partially surrounding the end of stum S, adjacent to the straps 16 and air introduced and brought to the desired pressure through the air valve 25.

It has been discovered that, because of a "milking" phenomenon attributable to the annular distal end 24, 24, post-operative edema has been rapidly cleared up by the mechanical action of the surrounding annular end of the air sac upon the amputated area of the stump S, resulting in much more rapid, complete and satisfactory recovery for the patient.

It is believed that the rapid elimination of post-operative edema is caused by the patient's own activity in alternately driving the stump down into the air sac and removing weight, in an alternating style as a part of the walking operation. This mimics the physiologic muscle contractions which are the main means of returning fluid from the extremities to the heart. The air sac 10, as shown in the drawings, is empty except for the presence of air and there are no obstacles impeding the free flow of air from place to place within the air sac 10. The milking action is greatly enhanced by the presence of the outer casing 13, which prevents the air sac from ballooning outwardly excessively, and which exerts pressure uniformly on the stump. In the same manner, the supporting means such as the straps or webs 16, for example, perform an analgous function at the distal end of the air sac 10. Accordingly, the following features are achieved and advantages enjoyed in the early use of a prosthetic device according to this invention:

1. Confinement of forces in a confined space, prohibiting abnormal distortion within the air sac.

2. The establishment of uniform vector forces directed inwardly at essentially all portions of the stump.

3. Provision of protection for the patient, ensuring his safety and preventing sudden deflation of the air sac 10, and even preventing catastrophy in the event of sudden deflation.

4. The provision for uniformly distributed pressure on the stump, even while the patient is resting. The provision of such uniform pressure, even at the distal end of the stump, provides the patient the benefits of a uniform pressurized environment for the stump, all without creating any problems of skin irritation that are often created with an elastic bandage, which is difficult to wrap with uniform pressure and sometimes produces a "tourniquet" effect.

It will be appreciated that the casing 13 may be made of any desired rigid material. Although fiberglass is excellent for its strength and light weight, various metals may be substituted. Although the casing 13 may be composed of an opaque material if desired, it is often very helpful to provide it as a transparent material, so that the attending physician may have an opportunity to observe the condition of the stump and the effectiveness of the prosthetic device visually. Other materials may also be selected, all within the skill of the art.

It will be appreciated that similarly, the air sac may be composed of any desired material, but plastic air sacs have been found to be quite advantageous. The air valve 25 serves conveniently for inflating the air sac, and a small separate air tank of appropriate size and design may be selected for use in combination with the air sac 10 in the actual use of the prosthetic device.

It will also be appreciated that various protuberances of different sizes and shapes may be substituted for the rings that are shown in FIG. 1. The important consideration is that they project inwardly and cause a deviation of the smooth contour of the air sac 10, providing a gripping effect between the air sac 10 and the casing 13. This provides an excellent phenomenon of vertical stabilization which is an important and advantageous feature of the invention.

Accordingly, it will be appreciated that this invention provides a novel combination including an air sac which is intimately in contact with the amputative stump, a rigid covering means which prevents inadvertent puncturing of the air sac and adds stability and resistance to the air sac, and a webbing or other supporting means which extends across the space beneath the distal end of the air sac, confining the air sac as does the casing 13, all contributing to a synergistic effect, providing a surprising "milking" action on the end of the stump S to reduce edema. This is particularly important in connection with use of the device shortly after the amputation procedure has been effected.

Although this invention has been described with reference to certain specific forms thereof, it will be appreciated that various changes may be made, including substitution of equivalent elements for those shown and described, the use of certain features independently of other features, and reversals of parts, all without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

The following is claimed:

1. In a prosthetic device for therapeutic treatment of an amputative stump, the combination which comprises means providing an air sac shaped for arrangement in intimate contact with the sides and bottom of the amputative stump, said air sac being essentially empty except for said air, and being internally open and unimpeded with respect to flow of air from place to place within said sac, means for introducing air into said sac for maintenance of said air under pressure therein, said air sac having an internal and an external side wall which are shaped downwardly and inwardly in a manner to provide an air space which is adapted to wrap substantially around the distal end of the stump, means for providing a substantially rigid casing surrounding and confining said air sac, and supporting means for said casing, wherein said air sac has a sealed distal end adapted to be located in the area of the distal end of the amputative stump, and wherein a shock-absorbing resilient supporting means is provided extending under and in contact with said distal end of said air sac, and arranged to exert a force against said distal end in a direction to urge it upwardly toward and against said distal end of said stump.

2. The prosthetic device defined in claim 1, wherein said supporting means includes a plurality of straps extending across the prosthetic device.

3. The prosthetic device defined in claim 1, wherein said sealed end is annular.