Abstract:
Vacuum-assist artificial limb assemblies ( 10, 94 ) are provided having a socket ( 22, 104 ) for receiving a residual limb ( 20 ). The assemblies ( 10, 94 ) include a vacuum pump and control assembly ( 18, 100, 102 ) with a selectively operable vacuum pump ( 72, 116 ) controlled by a microprocessor ( 44, 102 ). The microprocessor ( 44, 102 ) is also connected with an on-off switch ( 48, 146 ), pressure adjust buttons ( 68, 148 ), a pressure read-out ( 66, 150 ), and an optional alarm ( 70 ). In use, a pressure transducer ( 74 ) in communication with the interior of socket ( 22, 104 ) and coupled with microprocessor ( 44, 102 ) monitors negative pressure conditions within the socket ( 22, 104 ), and the microprocessor ( 44, 102 ) operates pump ( 72, 116 ) in response to transducer pressure signals. In this manner, the vacuum-assist operation of assemblies ( 10, 104 ) is essentially automatic. In one embodiment, a vacuumization assembly ( 100 ) including an air induction component ( 114 ) and a mated vacuum pump component ( 116 ) are located within a housing ( 108 ) forming a part of socket ( 104 ), and a separate controller ( 102 ) is coupled with vacuum component ( 116 ) for control thereof.

Description:
RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. patent application Ser. No. 11/081,205, filed Mar. 16, 2005, and this application is incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention is broadly concerned with improved prosthetic devices such as artificial limb assemblies of the type incorporating a vacuum pump in order to establish negative pressure conditions serving to securely attach the devices to residual limbs. More particularly, the invention is concerned with such prosthetic devices, and methods of operation thereof, wherein the devices include a vacuum-generating assembly including a powered vacuum source as well as a digital control assembly (e.g., a microprocessor) which is programmed to develop and maintain preselected negative pressure conditions. The digital control apparatus may be permanently mounted upon a portion of the artificial limb assembly (e.g., a pylon) or may be a separate device. In one embodiment, a two-component vacuumization assembly may be located within a housing forming a part of a residual limb-receiving socket.  
         [0004]     2. Description of the Prior Art  
         [0005]     An amputee losing part of an extremity or limb such as an arm or leg normally requires a prosthetic device such as an artificial limb to maintain optimum activity and functionality. The remainder of amputated limbs are commonly referred to as a residual limbs, and these come in various sizes and shapes, which may vary over time. Many new amputations present residual limbs which are slightly bulbous or cylindrical in shape, whereas older amputations may have atrophied to a more conical shape. Residual limbs may also have individual problems owing to scarring, skin grafts, bony protuberances, uneven volume, neuroma, pain, or edema.  
         [0006]     Broadly speaking, prosthetic limb assemblies provide a socket which is typically custom-manufactured for a particular residual limb, in order to ameliorate the problems outlined above. Also, a pylon or other elongate connector is secured to the socket and in turn supports a prosthetic foot or hand device. In recent years, artificial limb assemblies have made use of vacuum sources or pumps in order to generate negative pressure conditions serving to secure the socket to the residual limb. This type of connection has been found to be superior to prior devices using only mechanical connections such as straps.  
         [0007]     For example, Jim Smith Sales, Inc. has distributed vacuum-type prosthetic devices under the Trademark TSS VACULINK. These devices include a vacuum pump which is motion-activated, e.g., as the user walks in the case of a prosthetic leg device, the walking motion and weight of the user provides the power needed to operate the vacuum pump. Other such devices are illustrated in U.S. Pat. Nos. 6,726,726, 6,761,642 and 5,549,709.  
         [0008]     While prior motion or weight-operated vacuum prosthetic devices have achieved substantial success in the market place, they suffer from a number of drawbacks. First, during periods where the amputee is at rest, no vacuum can be generated. Thus, the user may experience a situation where the device becomes loose or even detaches from the residual limb, owing to inactivity over a period of time. Additionally, there is generally no way to periodically or continuously monitor the actual negative pressure conditions within the socket, so that the magnitude of negative pressure may vary over wide limits. It is also generally known that residual limbs tend to lose volume over the course of the day if the negative pressure within the socket decreases beyond a certain threshold. This can be a problem during periods of rest in these weight or motion operated devices. Finally, these prior motion or weight-activated devices are limited to particular applications such as specific types or brands of prosthetics and certain residual limb lengths.  
         [0009]     Accordingly, there is a need in the art for improved vacuum-type prosthetic devices which overcome the problems inherent in prior devices and are operable to establish and maintain negative pressure conditions on an essentially automatic basis regardless of the degree of activity of the user.  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention overcomes the problems outlined above and provides improved prosthetic devices such artificial limbs which have an electrically-powered on-board vacuum pump controlled by a digital controller such as a microprocessor. Broadly speaking, the artificial limb assemblies of the invention include a socket for receiving a residual limb and a vacuum source operatively coupled with the socket in order to generate a negative pressure therein; additionally, the assemblies have a digital control assembly coupled with the vacuum source and operable to control the operation thereof in order to maintain sufficient and consistent negative pressure within the socket to keep the limb assembly in place on the residual limb. The socket is preferably a hypobarically controlled prosthetic socket and the vacuum source is preferably a dual diaphragm, rechargeable battery or battery powered, microprocessor-controlled vacuum pump capable of maintaining a high level of negative pressure in the socket.  
         [0011]     The preferred digital control assemblies of the invention include user-operated structure for adjusting the output of the vacuum source for adjusting the level of negative pressure within the socket. In this way, maximum comfort and operational flexibility can be obtained. These effects are enhanced by means of a read-out device forming a part of the control assembly for displaying the negative pressure conditions within the socket. Preferably, the entire vacuum pump and control assembly is self-contained and mounted on the artificial limb, such as on the upright pylon of an artificial leg assembly. Optionally, a perceptible alarm may also be included which will give an alarm signal (e.g., audible or visual) if the battery fails or is low. In preferred forms, the read out device will be able to display a variety of information selected from the group consisting of current vacuum pressure within the socket, the set point of the maximum and minimum vacuum pressures to be drawn in the socket, and remaining battery life.  
         [0012]     Digital control of the vacuum pump is achieved by using the digital controller to periodically or essentially continuously monitor vacuum conditions within the socket. To this end, a pressure transducer is preferably coupled in communication with the interior of the socket and delivers pressure signals to the digital controller; the latter initiates or terminates pump operation in response to such pressure signals. Preferably, the range of pressures to be maintained will be able to be programmed on each individual pump unit. For example, some individuals will prefer to have a negative pressure variation of 1 inch of mercury or less while others will prefer a wider range. However, it is understood that the invention herein is capable of all such types of variation.  
         [0013]     In one preferred embodiment of the present invention, the invention includes a socket assembly, a flexible liner, and a vacuum pump and control assembly. The flexible liner is preferably a synthetic resin sock such as a conventional urethane liner adapted to snugly fit over a residual limb. The socket assembly generally includes an upright, open-top socket having a closed lower end adapted to receive and attach to a prosthetic limb. The open top of the socket receives the residual limb and liner therein. A opening adapted to receive a vacuum hose is also present on the socket assembly and this opening fluidly connects the exterior of the socket assembly with the interior. In some preferred forms, the opening is a threaded bore or is adapted to receive a conventional barb connector therein. A vacuum hose connects the opening with the vacuum pump and control assembly. Initiation of a pump cycle begins when the digital control responds to a pressure signal below the minimum threshold set by the user. The vacuum generated by the pump draws the liner to the socket and the residual limb to the liner, thereby providing a secure fit, a decrease (or elimination) of gaps between the residual limb, liner, and socket, consistent negative pressure within the socket assembly, and a decrease in residual limb volume loss.  
         [0014]     Alternately, a vacuumization assembly including an air induction component and a mated vacuum pump component are located within a specially configured housing forming an integral part of the residual limb-receiving socket. In this embodiment, a separate, user-controlled digital microprocessor controller is operatively coupled with the vacuum pump component in order to energize and control the operation thereof.  
         [0015]     In other preferred forms, the invention is coupled with a conventional prosthetic pylon and appendage such as a hand or foot. Advantageously, the socket assembly of the present invention is not limited to any particular prosthetic brand and does not require any particular stump length or size. Accordingly, it is universally adaptable to a wide variety of currently existing applications.  
         [0016]     Thus, the vacuum pump and control assembly may be secured to the prosthetic device using any conventional means including tape, elastic bands, screws, bolts, hook and loop wraps or straps, custom designed pockets, clips, and the like. However, it is understood that components of the vacuum pump and control assembly may also be secured to a location remote from the prosthetic such as on or in the socket assembly (e.g. in a custom container mounted on the socket) or even to the individual.  
         [0017]     Preferred forms of the invention may also include a sealing means adapted to maintain separation between the interior of the socket assembly to which the vacuum pressure is applied and the outside atmosphere. This can be accomplished using a variety of means including customized synthetic resin sleeves, conventional sealing sleeves, gators, tape, and elastic bands. A good sealing means will decrease the number of pump cycles the vacuum pump will initiate. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a side view partially in phantom of an artificial limb assembly in accordance with the invention, shown mounted upon a residual limb;  
         [0019]      FIG. 2  is an enlarged view partially in vertical section depicting the socket assembly forming a part of the artificial limb assembly;  
         [0020]      FIG. 3  is a schematic representation of the vacuum pump and control assembly of the artificial limb assembly;  
         [0021]      FIG. 4  is a side view partially in phantom of an artificial limb assembly in accordance with the invention, shown mounted on a residual limb and having a two-component vacuumization assembly located within an integral housing forming a part of the socket of the assembly;  
         [0022]      FIG. 5  is an enlarged, fragmentary view in partial vertical section, depicting the construction of the socket depicted in  FIG. 4 , with the two-component vacuumization assembly therein;  
         [0023]      FIG. 6  is an exploded perspective view illustrating the preferred vacuumization assembly for the limb assembly of  FIG. 4 ;  
         [0024]      FIG. 7  is an exploded perspective view similar to that of  FIG. 6 , but illustrating the vacuumization assembly from the bottom thereof; and  
         [0025]      FIG. 8  is an elevational view of the preferred controller forming apart of the artificial limb assembly of  FIG. 4 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
     Embodiment of FIGS.  1 - 3   
       [0026]     Turning now to the drawings, an artificial limb assembly  10  is depicted in  FIG. 1  and broadly includes a socket assembly  12 , a pylon  14 , a prosthetic foot  16 , and a vacuum pump and control assembly  18 . The limb assembly  10  is adapted to be coupled with a residual limb  20 , in this case, the residuum of a below-the-knee amputation. It will be appreciated, however, that the invention is not limited to this specific type of artificial limb assembly, but can be used for other varieties, e.g., above-tie-knee amputations or for artificial arm assemblies.  
         [0027]     The socket assembly  12  is best illustrated in  FIG. 2 , where it will be seen that it includes an upright, open-top relatively rigid socket  22  presenting a lower closed-end  24  and an upper margin  26 . It will also be seen that the socket  12  includes a threaded bore  28  receiving a threaded pneumatic nipple  30 , which is important for purposes to be described. Generally, the socket  22  would be custom-prepared for an individual patient, in order to best accommodate the residual limb  20 .  
         [0028]     The pylon  14  is itself conventional and includes a primary aluminum and/or composite rod  32  having endmost upper and lower clamps  34  and  36 . The upper clamp  34  includes a socket adapter  38  which is received within the body of socket  22  at end  24 , and selves to provide an appropriate connection between socket  22  and pylon  14 . Similarly, lower clamp  36  has an adaptor  40  affording a connection to prosthetic foot  16 .  
         [0029]     The vacuum pump and control assembly  18  is located within a housing  42  secured to pylon rod  32  by any conventional means such as those described previously. Generally speaking, the function of assembly  18  is to create negative pressure conditions within socket  22  and to maintain these conditions within predetermined limits. Attention is directed to  FIG. 3  which depicts the components of assembly  18 . Specifically, assembly  18  includes a digital microprocessor controller  44  powered by a battery  46  and with an on-off switch  48  located in the leads  50  between the controller and battery. The microprocessor  44  is operatively connected to a number of components via leads  52 ,  54 ,  56 ,  58 ,  60 ,  62 , and  64 . Specifically, the leads  52 ,  54  are coupled to a conventional pressure display  66  while leads  56  and  58  are coupled to manual pressure adjust buttons  68 . The leads  60  are connected with a vibratory alarm  70  while leads  62  are coupled to a vacuum pump  72 . Finally, the leads  64  are connected with a pressure transducer  74 .  
         [0030]     The pump  72  includes a vacuum inlet  76  as well as an opposed venting outlet  78 . A flexible vacuum line  80  extends between inlet  76  and nipple  30  and is equipped with a check valve  82 . If desired, an in-line filter (not shown) may be installed in the line  80  between the pump and the socket in order to filter small particles, lint and dust and to prevent these from entering the pump. As illustrated, the transducer  74  is in communication with line  80  upstream of check valve  82 .  
         [0031]     In use, the residual limb  20  is first inserted with socket  22 . Normally, the residual limb is covered by a pliable synthetic resin sock or liner  84  having a resilient layer  86  and an outer layer  88 . An optional synthetic resin sleeve  90  may be applied over the juncture between the residual limb  20  and upper margin  26  of socket  22 , with the sleeve  90  being held in place by elastic band  92 .  
         [0032]     Next, the assembly  18  is used to create negative pressure conditions within socket  22  serving to hold residual limb  20  in place therein. This involves actuating on-off switch  48  which, through microprocessor  44 , initiates operation of vacuum pump  72  to generate a predetermined vacuum pressure within the socket  22 . As manufactured, the controller  44  would typically be set to establish and maintain negative pressure conditions of between 10-15 inches of mercury, which has been found to maintain optimal suspension and residual limb control during normal activity. The practical limit of negative pressure is around 22-25 inches of mercury, these being the maximum levels the pump will achieve for extremely high activity levels, such as patient&#39;s competing in sports. However, the nominal level can readily be changed by manipulation of the pressure adjust buttons  68 . The pressure transducer  74  measures the negative pressure conditions within line  80  and thus socket  22 , and the microprocessor  44  uses the transducer output to control the operation upon vacuum pump  72 . This occurs not only during initial start-up, but periodically or even essentially continuously while the assembly  10  is being worn. Thus, if the negative pressure conditions within socket  22  reach a point outside of the predetermined, selected range for the user, the microprocessor  44  initiates operation of pump  72  as needed. For example, a given user may select a range of 12-19 inches of mercury. When the vacuum conditions within socket  22  bleed down to 12 inches or below, the pump  72  is actuated to return the vacuum level to the desired 19 inches of mercury, whereupon the pump operation is terminated. Also, as a separate safety measure, the alarm  70  may be actuated in the event of any out of specification pressure conditions, to generate a perceptible alarm signal such an audible or vibratory signal.  
       Embodiment of FIGS.  4 - 8   
       [0033]     This embodiment is similar in many respects to that of  FIGS. 1-3 , and where appropriate identical reference numerals will be used to indicate identical components.  
         [0034]     In more detail, the artificial limb assembly  94  of  FIG. 4  broadly includes a socket assembly  96 , pylon  98 , prosthetic foot  16 , vacuumization assembly  100 , and controller  102 . The assembly  92  is adapted to be coupled with exemplary residual limb  20 .  
         [0035]     The socket assembly includes an upright, open top, relatively rigid socket  104  presenting an upper margin  106  as well as a depending, hollow, lower housing  108  terminating in a generally horizontal, apertured bottom wall  110 . The socket  104  would be custom-prepared for each individual patient in order to best conform with residual limb  20 .  
         [0036]     The pylon  98  is identical with previously described pylon  14 , except that the pylon  98  has an uppermost, apertured flange  112  which mates with housing bottom wall  110  as will be described.  
         [0037]     The vacuumization assembly  100  is best illustrated in  FIGS. 6 and 7  and includes an upper air induction component  114 , as well as a mated, lower vacuum pump component  116 . As described, these components  114 ,  116  are designed to fit within housing  108  of socket  104 . The air induction component  114  is generally cylindrical but presents a somewhat dished concave upper surface  118  which communicates with the interior of socket  104 . The component  114  has a total of three vacuum ports  120  extending through upper surface  118  and which communicate via lateral ports (not shown) with a central, lower vacuum port  122 ; the port  122  is located within a recess  124  formed in the bottom of component  114  ( FIG. 7 ). A pair of outer and inner O-ring seals  126 ,  128  are located within corresponding groves  126   a,    128   a,  located about the outer sidewall of component  114  and the inner sidewall of recessed  124 , respectively.  
         [0038]     The vacuum pump component  116  is also of generally cylindrical design and mates with component  114  within housing  108 . The component  116  houses conventional vacuum pump and pressure transducer apparatus (not shown). The component  116  further has an upstanding tubular coupler  130  equipped with a screen-type filter  132  extending from the upper surface thereof The coupler  130  is designed to snugly fit within recess  124 , with O-ring  128  serving to seal the connection. Again referring to  FIGS. 6 and 7 , it will be seen that the component  116  has an exhaust port  134  and a plug-receiving bore  136  for controller  102 . Finally, the bottom surface of component  116  is equipped with four recessed, threaded nuts  138  in registry with corresponding bottom wall openings  139 , which are important for purposed to be described.  
         [0039]     As best illustrated in  FIG. 5 , the components  114 ,  116  are located within housing  108  in stacked relationship, i.e., the bottom wall of component  116  contacts housing bottom wall  110 , and component  114  sits atop component  116 , with coupler  130  extending into recess  124 ; the O-rings  126  and  128  effect substantially air-tight seals between the outer surface of component  114  and the inner surface of housing  108 , and between coupler  130  and the sidewall of recess  124 , respectively. The housing  108  also has access openings (not shown) which register with port  134  and bore  136 .  
         [0040]     The pylon  98  is secured to socket assembly  96  by means of four attachment screws  140  which extend through flange  112  and pass through openings  139  for receipt within the threaded nuts  138 .  
         [0041]     The controller  102  includes a controller box  142  having a battery compartment  144  and appropriate control circuitry of the type described in connection with the first embodiment. Such circuitry includes a digital microprocessor and related components, well-known to those skilled in the art. The controller  102  also has an on-off switch  146 , vacuum control buttons  148 , a digital vacuum read-out  150 , and optional alarm (not shown), all coupled with the internal control circuitry. An elongated lead wire  152  coupled with the internal control circuitry extends from the box  142  and has a terminal jack or plug  154  which is adapted to extend through housing  108  and into bore  136  of component  116  (see,  FIG. 4 ).  
         [0042]     The use of limb assembly  94  is very similar to that of assembly  10 , and again like reference numerals will be used where appropriate to indicate identical components. Generally, the vacuum pump within component  116  draws a negative pressure within socket  104  through the ports  120 ,  122 , the former being adjacent the layer  88  of air-permeable sock or liner  84  (see  FIG. 5 ). However, in this case the controller  102  is separate from the remainder of the assembly  94 , and can be mounted onto socket  104  by means of Velcro or a mounting clip. Alternately, the user may maintain controller  102  in a pants pocket or pouch separate from the socket  104 . In any case, the controller  102  is coupled to component  116  via lead  152  and jack  154  throughout the operation of the assembly  94 .  
         [0043]     Typically, the user would initiate operation of component  116  via controller  102  in order to establish an appropriate negative pressure condition within socket  104 , as determined by the pressure transducer. The controller  102  then operates to maintain this negative pressure within socket  104  over time, by appropriate energization of the vacuum pump within component  116  as necessary. Also, the user may adjust the negative pressure level by appropriate manipulation of buttons  148  on box  142 .  
         [0044]     The invention provides a number of advantages not heretofore possible with vacuum-type artificial limb assemblies. Use of the microprocessor  44  in assembly  18 , or in controller  102 , permits essentially automatic operation which can be readily programmed to achieve and maintain a desired vacuum condition. The invention does not rely upon any weight or motion-activation, which can be problematic during periods of patient rest or where there are patient limits on the use of such equipment. Moreover, there is no practical patient weight limitation when using the limb assemblies of the invention, because of the non-structural usage of the assemblies.