Abstract:
The apparatus of the present invention stretches the carpal ligament and the flexor retinaculum, as well as the superficial structures and muscles of the hand, in a safe manner under precise control of the patient or a healthcare professional. Various embodiments of the inventive apparatus include a housing for receiving the patient&#39;s hand with an open top portion and with two internal regions adapted and configured to contact the thenar and hypothenar regions of the patient&#39;s palm, while a closeable cover, that fits over the open top region of the housing, includes a pressure element positioned and configured to apply pressure to the dorsal portion of the hand when the cover is depressed and/or closed such that opposing forces of the internal regions pressing on the thenar and hypothenar regions of the palm while the pressure element is pressing on the dorsal portion of the hand cause the carpal ligament and the flexor retinaculum to stretch expanding the carpal tunnel and relieving pressure on the median nerve.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application Serial No. 60/315,088, filed Aug. 27, 2001. This application is related to four concurrently filed co-pending patent applications, namely U.S. Ser. No. ______, entitled Configurable Apparatus and Method for Treating Carpal Tunnel Syndrome, U.S. Ser. No. ______, entitled Adjustable Apparatus and Method for Treating Carpal Tunnel Syndrome, U.S. Ser. No. ______, entitled Adaptable Apparatus and Method for Treating Carpal Tunnel Syndrome, U.S. Ser. No. ______, entitled Automatic Apparatus and Method for Treating Carpal Tunnel Syndrome, as well as co-pending patent application U.S. Ser. No. 10/199,747, entitled Apparatus and Method for Treating Carpal Tunnel Syndrome, filed Jul. 18, 2002, the contents of which are all hereby incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates generally to treatment of carpal tunnel syndrome, and more particularly to a non-invasive apparatus and method for treatment of carpal tunnel syndrome.  
         BACKGROUND OF THE INVENTION  
         [0003]    Carpal tunnel syndrome is a physiological disorder that afflicts over 850,000 people each year in the United States alone. In order to better understand the cause of the carpal tunnel syndrome and the difficulty in treating this serious disorder, a detailed explanation of the physiological factors and causes of carpal tunnel syndrome is presented below. Carpal tunnel syndrome is caused by a deleterious increase in pressure on the median nerve which passes through the carpal tunnel (or canal) in the hand, adjacent to the wrist. The deleterious increase in pressure, which is commonly brought on by prolonged repetitive motion of the hand and digits, is often caused by inflammation or damage to tendons for the hand which pass through the carpal tunnel along with the median nerve. Pressure increases can also be caused by narrowing of the carpal canal and by generalized swelling of the structures in the hand. Thus, when the carpal tunnel is narrowed from ligament shortening, muscle development or structural inflammation, the median nerve is undesirably compressed.  
           [0004]    The carpal tunnel is formed by the eight carpal bones of the hand adjacent the wrist, which bones are arranged in two rows forming a generally U-shaped inverted arch-like “tunnel” structure. The three large carpal bones of the proximal row (i.e., closest to the chest), beginning laterally (i.e., from the outside with the hand directed downward and the palm facing forward), are the scaphoid, lunate, and triquetrum; the smaller pisiform bone sits on the palmar surface of the triquetrum. The distal row, from lateral to medial, consists of the trapezium, trapezoid, capitate, and hamate carpal bones. The vault of the carpal tunnel is formed by the carpal ligament and the flexor retinaculum. Nine tendons, their tendon sheaths, and the median nerve pass through the tunnel.  
           [0005]    The carpal ligament is made of collagen and elastin and extends from the pisiformis and hamulus of hamate bones on the ulnar aspect of the tunnel to the tubercle (i.e., projection) of trapezium and the tubercle of the scaphoid bones on the radial (i.e. lateral) aspect of the carpal tunnel. The flexor retinaculum also stretches across the carpal tunnel and attaches to, on the medial aspect of the carpal tunnel, the pisiform bone and the hook of hamate, and, on the lateral aspect, the tubercle of the scaphoid and trapezium bones. The proximal border of the flexor retinaculum corresponds generally to the transverse skin crease at the base of the hand/wrist. The carpal ligament and flexor retinaculum, along with the carpal bones, form the restricted space through which the median nerve and several tendons pass.  
           [0006]    Symptoms of carpal tunnel syndrome include tingling sensation in the hand, discomfort, numbness, and pain localized in the hand or radiating up the arm to the shoulder. All of these symptoms can occur during the day or can make the patients wake up at night. In advanced cases, there is atrophy and weakness of the thenar area of the hand which may weaken the grip and cause objects to fall out of the hand.  
           [0007]    Conventional treatment of carpal tunnel syndrome is divided into surgical (invasive) and conservative (non-invasive). Surgical treatment consists of making an incision on the palmar aspect of the hand and splitting the carpal ligament, thus partially opening the carpal tunnel and relieving the pressure. This procedure, while occasionally successful, often has negative consequences, which include, but are not limited to, non-resolution of symptoms often requiring a second surgery, pain in the area of the scar, and injury to the superficial palmar branch of the median nerve causing persistent neurologic symptoms such as loss of full control over the hand. Furthermore, this procedure is very expensive. Understandably, surgical treatment is often considered as a last option.  
           [0008]    Conservative, non-invasive treatment is typically separated into three categories—mild, moderate and alternative. Mild treatments may involve the use of anti-inflammatory medications, application of resting hand splints, physical therapy, modification of patient&#39;s activities that cause the condition, and even a change in the patient&#39;s job. Moderate treatments involve one or more mild treatments coupled with cortisteriod injections. Finally, alternative methods include acupuncture, massage, application of magnets, tai-chi exercises, and the like.  
           [0009]    However, none of the above treatments have produced uniformly positive results. While some treatments may alleviate the symptoms of carpal tunnel syndrome in individual patients, the symptoms often return when the course of treatment is terminated. Furthermore, one of the main disadvantages of the various treatment approaches is that they must be delivered by a healthcare provider such as a physician or a physical or occupational therapist. This adds a significant level of inconvenience to the patient who must allocate time to visit the healthcare provider for injections and/or physical therapy. Medications that are used to provide relieve from the pain and discomfort caused by carpal tunnel syndrome also suffer from a number of disadvantages. For example, certain medications have undesirable side effects or interactions with the patient&#39;s other medications, if any. As a result, a number of techniques for treating carpal tunnel syndrome that address at least some of the above problems have been developed over the years. Some merely maintain the patient&#39;s hand in a neutral position (such as the device disclosed in U.S. Pat. No. 5,014,689) to prevent the symptoms from worsening. Another approach involved mechanical stretching of the carpal ligament, as disclosed in U.S. Pat. No. 5,256,136. Yet another series of techniques advocated placement of a compression bracelet on the forearm (U.S. Pat. No. 5,441,058), or on the wrist (U.S. Pat. No. 5,468,220) to apply a predetermined pressure on certain portions of the forearm, or wrist, respectively, in order to widen the carpal tunnel and thus provide relief to the patient suffering from carpal tunnel syndrome.  
           [0010]    However, the above-described previously known devices suffer from a crucial disadvantage. Application of pressure to different portions of the forearm and/or the wrist only has a minimal effect on widening the carpal tunnel, and may only provide temporary relief from carpal tunnel syndrome rather than eliminating or suppressing the condition.  
           [0011]    Further development in the area of mechanical treatment of carpal tunnel syndrome continued, and eventually resulted in discovery of the Porrata principle, disclosed in the commonly assigned U.S. Pat. No. 6,146,347 to Humberto Porrata, that provides a novel and advantageous device and method for treating carpal tunnel syndrome that solve the problems posed by previously known devices and techniques. Most importantly, research conducted in conjunction with development of the Porrata device, has shown that carpal tunnel syndrome may be treated with great effectiveness by precise controlled transverse stretching of the carpal ligament and the flexor retinaculum. The 6,146,347 patent disclosed a splint-like device that fit over the patient&#39;s hand and a portion of the wrist. The device included rigid sections for contacting the thenar and hypothenar portions of the hand and a selectable active pressure source that, when actuated, applied pressure to the dorsal portion of the patient&#39;s hand opposed by the forces delivered by the thenar and hypothenar sections of the device in such a manner, as to transversely stretch the carpal ligament and the flexor retinaculum in a comfortable and controlled manner.  
           [0012]    Nevertheless, the device of the 6,146,347 patent is susceptible to improvement. First, because of its construction it generally must be fabricated in different sizes to fit various patients, and patients with unusual hand sized or shapes may need custom-fabricated devices. Second, it generally requires an active adjustable pressure source such as a bladder and pump combination for delivering pressure to the dorsal portion of the hand.  
           [0013]    It would thus be desirable to provide an apparatus and method for treating carpal tunnel syndrome by stretching the carpal ligament and the flexor retinaculum of a patient&#39;s hand in a comfortable and controlled manner. It would further be desirable to provide an apparatus and method for treating carpal tunnel syndrome embodied in a device that is dynamically adaptable to patients of various physical characteristics. It would also be desirable to provide an apparatus and method for treating carpal tunnel syndrome embodied in a device that is easy and inexpensive to manufacture.  
         SUMMARY OF THE INVENTION  
         [0014]    The apparatus and method of the present invention advantageously overcome the problems and drawbacks of previously known approaches for treating carpal tunnel syndrome. Similarly to the device disclosed in the commonly assigned U.S. Pat. No. 6,146,347, which is hereby incorporated by reference in its entirety, the main objective of the present invention is to apply the Porrata principle to transversely stretch the carpal ligament and the flexor retinaculum, as well as the superficial structures and muscles of the hand, in a safe manner under precise control of the patient or a healthcare professional. The apparatus and method of the present invention enable the Porrata principle to be implemented in a device that may be readily used by patients with any size or shape hands. Furthermore, the inventive apparatus is very simple and inexpensive to manufacture.  
           [0015]    Controlled and monitored use of the inventive apparatus dynamically treats carpal tunnel syndrome through the application of pressure to portions of the palm of the hand (in the thenar and hypothenar areas) while at the same time providing application of pressure, in the opposite direction, to a portion of the dorsum of the hand. This procedure stretches the carpal ligament, the flexor retinaculum, and superficial structures and muscles of the hand in the palmar aspect of the hand, in a readily, safely controllable and comfortable manner.  
           [0016]    Considering that the constitutions of the carpal ligament and the flexor retinaculum are soft tissue composed of collagen and elastin, stretching the carpal ligament and the flexor retinaculum is effective for decreasing compression on the median nerve by increasing the diameter of the tunnel and decreasing the rigidity of the retinaculum and the carpal ligament, thus alleviating the symptoms of carpal tunnel syndrome.  
           [0017]    Various embodiments of the inventive apparatus commonly include a housing for receiving the patient&#39;s hand with an open top portion and with two internal regions adapted and configured to contact the thenar and hypothenar regions of the patient&#39;s palm, while a closeable cover that fits over the open top region of the housing includes a pressure element positioned and configured to apply pressure to the dorsal portion of the hand when the cover is depressed and/or closed.  
           [0018]    Accordingly, the inventive apparatus is inexpensive and readily usable by any patient to prevent progression of carpal tunnel syndrome and to provide relief from symptoms by increasing the cross sectional area of the carpal tunnel, thus decreasing compression on the median nerve and decreasing the resulting symptoms.  
           [0019]    Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    In the drawings, wherein like reference characters denote like elements throughout the several views:  
         [0021]    [0021]FIG. 1 is a cross section view of a first embodiment of the inventive apparatus for treating carpal tunnel syndrome;  
         [0022]    [0022]FIG. 2 is an isometric top view of the first embodiment of the inventive apparatus for treating carpal tunnel syndrome of FIG. 1;  
         [0023]    [0023]FIG. 3 is a cross section view of the first embodiment of the inventive apparatus for treating carpal tunnel syndrome of FIG. 1 during utilization.  
         [0024]    [0024]FIG. 4 is a cross section view of a second embodiment of the inventive apparatus for treating carpal tunnel syndrome;  
         [0025]    [0025]FIG. 5 is a cross section view of a third embodiment of the inventive apparatus for treating carpal tunnel syndrome;  
         [0026]    [0026]FIG. 6 is a cross section view of a fourth embodiment of the inventive apparatus for treating carpal tunnel syndrome;  
         [0027]    [0027]FIG. 7 is a cross section view of a fifth embodiment of the inventive apparatus for treating carpal tunnel syndrome;  
         [0028]    [0028]FIG. 8 is a cross section view of a sixth embodiment of the inventive apparatus for treating carpal tunnel syndrome; and  
         [0029]    [0029]FIG. 9 is an isometric top view of the sixth embodiment of the inventive apparatus for treating carpal tunnel syndrome of FIG. 6.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0030]    The present invention is described with reference to various materials that compose the inventive structures and elements thereof, and to various devices for selectively applying pressure to a specific area of the hand, by way of example only—it should be understood that the apparatus and method of the present invention may be utilized with any materials or selective pressure sources having properties similar to those described in the exemplary embodiments, without departing from the spirit of the invention.  
         [0031]    The essence of the Porrata approach, disclosed and described in greater detail in the above-incorporated U.S. Pat. No. 6,146,347, involves applying pressure to a portion of the top surface of the hand (i.e., the central dorsal region), while at the same time applying opposing pressure to the thenar and hypothenar regions of the palm. The apparatus and method of the present invention advantageously implement the Porrata principle in a simple to use device that works equally well with different hand shapes and sizes.  
         [0032]    Referring now to FIG. 1, a first embodiment of an inventive apparatus  10  is shown. The apparatus  10  includes a housing  12  with a first support element  14  for supporting the thenar region of the hand, and a second support element  16  for supporting the hypothenar region of the hand. The housing  12  has side walls  11  and may be composed of a rigid material such as metal, hard plastic or wood, or a resilient material such as fiberglass or resilient plastic, or a combination thereof. The support elements  14 ,  16  may be rigid portions of the housing  12  composed of the same material or, alternately, may incorporate respective resilient comfort elements  28 ,  30  to improve contact with the respective thenar and hypothenar regions of the hand and to improve patient comfort. The support elements  14 ,  16  are substantially parallel to each other generally along the longitudinal axis of the patient&#39;s hand. The comfort elements  28 ,  30  may be composed of any resilient material, including but not limited to: soft plastic, silicone gel, padding, foam, spring elements, and a fluid or air-filled bladder. Optionally, the comfort elements  28 ,  30  may incorporate active pressure sources such as inflatable bladders or electromagnetic plates. The support elements  14  and  16  may be adjustable in position and orientation to better correspond to the size and shape of the patient&#39;s hand. Alternatively, the support elements  14  and  16  may incorporate active pressure sources such as inflatable bladders or electromagnetic plates.  
         [0033]    A cover  18  is pivotably attached to the housing  12  by a hinge element  20 , which may be a hinge or a piece of a flexible material. The cover  18  includes an elongated pressure element  22  disposed along its length and configured to contact a substantially central dorsal region of the hand along its longitudinal axis when the cover  18  is closed. Preferably, the pressure element  22  is sized to cover a sufficiently large portion of the surface of the dorsal portion of the hand, particularly in the transverse direction, to reduce the pressure applied to any particular nerve or artery in the hand. The pressure element  22  may be composed of a rigid material, such as metal, wood, plastic or fiberglass, or it may be composed of a resilient material such as soft plastic, silicone gel, padding, foam, and a fluid or air-filled bladder, or a combination of one or more resilient and rigid materials.  
         [0034]    Referring now to FIG. 2, a different view of the apparatus  10  is shown. FIG. 2 also shows that the apparatus  10  may also include an electronic device  40  that includes a laser or similar device adapted to specifically denature the proteins that make up the ligaments in the body, thus making it easier to stretch the ligaments. The electronic device  40  is preferably aligned with the flexor retinaculum or carpal ligament as the hand is placed in the apparatus  10 . The electronic device  40  may also include conventional sensors to measure the amount of stretching or elongation of the flexor retinaculum or carpal ligament through, e.g., tension measurements or displacement of carpal bones.  
         [0035]    Referring now to FIG. 3, the operation of the apparatus  10  is shown. A patient places a hand  300  into the housing such that the thenar region of the palm is positioned over the support element  14  and the hypothenar region of the palm is positioned over the support element  16  (or over optional comfort elements  28 ,  30 ). The wrist of the hand  300  is received through an open side portion of the housing  12 . The cover  18  is closed over the open top portion of the housing  12  such that the pressure element  22  contacts and presses down on the central dorsal region of the hand  300  along its longitudinal axis, which pressure is balanced and opposed by a second force formed by retaining action of the support elements  14 ,  16  exerted on the respective thenar and hypothenar regions of the hand. These opposing forces cause carpal bones of the hand to separate to stretch a carpal ligament and a flexor retinaculum of the hand, thus implementing the Porrata principle to widen the carpal canal and provide treatment of carpal tunnel syndrome to the patient.  
         [0036]    Referring back to FIG. 1, an optional releasable locking device  24 ,  26  may be positioned on the cover  18  and housing  12 , respectively to maintain the cover  18  in a locked position when it is closed over the hand. The locking device  24 ,  26  may be a clasp, a hook and loop combination (i.e. Velcro), a latch or any other releasable retaining device.  
         [0037]    Referring now to FIG. 4, a second embodiment of the inventive apparatus is shown as an apparatus  50 . The apparatus  50  includes a housing  52  with a side  54 , having a first set of independent support elements  62 ,  64  for supporting the thenar region of the hand, and a second side  56  having a second set of independent support elements  58 ,  60  for supporting the hypothenar region of the hand. The housing  52  may be composed of a rigid material such as metal, hard plastic or wood, or a resilient material such as fiberglass or resilient plastic, or a combination thereof. The independent support elements  58 ,  60 ,  62 ,  64  may be composed of a resilient material, including, but not limited to: soft plastic, silicone gel, padding, foam, and a fluid or air-filled bladder. Alternatively, they may be composed of a rigid material having a resilient lining, or spring elements  55  in contact with sides  54  and  56 . Multiple independent support elements  58 ,  60 ,  62 ,  64  are advantageous because they enable the apparatus  50  to adjust to the shape of the patient&#39;s hand. While only two independent support elements are shown on each side  54 ,  56 , a greater number of independent support elements may be implemented without departing from the spirit of the present invention.  
         [0038]    A cover  66  is pivotably attached to the housing  52  by a hinge element which may be a hinge or a piece of a flexible material. The cover  66  includes an elongated pressure element  68  disposed along its length and configured to contact a substantially central dorsal region of the hand along its longitudinal axis when the cover  66  is closed. The pressure region  68  may be composed of the same material as the cover  66 , such as metal, wood, plastic or fiberglass, or it may incorporate a resilient contact pad  70  composed of a resilient material such as soft plastic, silicone gel, padding, foam, and a fluid or air-filled bladder. An optional releasable locking device  72 ,  74  may be positioned on the cover  66  and housing  52 , respectively to maintain the cover  66  in a locked position when it is closed over the hand. The locking device  72 ,  74  may be a clasp, a hook and loop combination (i.e. Velcro), a latch, or any other releasable retaining device.  
         [0039]    Referring now to FIG. 5, a third embodiment of the inventive apparatus is shown as an apparatus  100 . The apparatus  100  is similar in construction and operation to the apparatus  10  of FIG. 1, except that a first mobile cylindrical roller  108  is positioned along a thenar support region  104 , and a second mobile cylindrical roller  110  is positioned along a hypothenar support region  106 . The cylindrical rollers are configured such that when a patient places their palm on the rollers  106 ,  108  and a cover  112  is closed, the pressure exerted by a pressure element  114  on the dorsal part of the hand causes the rollers  106 ,  108  to move away from a central portion of the palm along the respective sides  104 ,  106  to contact and support the respective thenar and hypothenar regions of the palm. Thus, this embodiment provides a dynamically adjustable support to the thenar and the hypothenar regions of the hand irrespective of the hand&#39;s size.  
         [0040]    Referring now to FIG. 6, a fourth embodiment of the inventive apparatus is shown as apparatus  150 . The apparatus  150  is similar in operation to the apparatus  10  of FIG. 1 (for example, sides  156  and  156  correspond to support elements  14  and  16 , and comfort elements  158  and  160  correspond to comfort elements  28  and  30 ), except that a cover  162  is composed of a flexible material or a resilient stretchable material. A pressure element  164  may be configured to move along the cover  162  via an adjustment device  166 . For example, the pressure element  164  (which may be similar to the pressure elements of the various other embodiments described herein) may include a knob seated within a slot in cover  162  by which the user may slide the pressure element  164  within the slot. This arrangement is advantageous because stretching tension can be applied to the cover  162  to thereby exert greater pressure on the dorsal region of the hand via the pressure element  164 . This adjustment device  166  may be incorporated into any of the other embodiments described herein. The adjustment device  166  may include or be coupled with a pressure measuring gauge allowing the user to increase the pressure on the dorsal portion of the hand to a pre-determined level. A releasable retaining device  168 ,  170  is configured to releasably retain the cover  162  when it is closed and is optionally configurable to maintain different levels of tension in the cover  162  when the cover  162  is stretchable.  
         [0041]    Referring now to FIG. 7, a fifth embodiment of the apparatus of present invention is shown as an apparatus  200 . The apparatus  200  is similar in operation to the apparatus  100  of FIG. 3 except that rollers  208 ,  210  in contact with spring elements  212 ,  214  move along a bottom of a housing  202 , rather than at an angle as in apparatus  100  of FIG. 3. Apparatus  200  includes sides  204 ,  206 , cover  216  with attached pressure element  218 , hinge  224 , and optional releasable locking device  220 ,  222 .  
         [0042]    Referring now to FIG. 8, a sixth embodiment of the inventive apparatus is shown as an apparatus  250 . The apparatus  250  includes a housing  252  having a generally semi-circular cross-section, with a first support element  254  for supporting the thenar region of the hand disposed along one side of an internal concave region of the housing, and a second support element  256  for supporting the hypothenar region of the hand disposed along the other side of the concave region of the housing. The housing  252  may be composed of a rigid material such as metal, hard plastic or wood, or a resilient material such as fiberglass or resilient plastic, or a combination thereof. The support elements  254 ,  256  may be composed of any resilient material, including but not limited to: soft plastic, silicone gel, padding, foam, spring elements, and a fluid or air-filled bladder. Optionally, the support elements  254 ,  256  may incorporate active pressure sources, such as inflatable bladders or electromagnetic plates. The support elements  254 ,  256  may be adjustable in position and orientation to better correspond to the size and shape of the patient&#39;s hand. Alternatively, the support elements  254 ,  256  may be composed of a substantially rigid material such as metal, plastic, wood or fiberglass.  
         [0043]    A cover  258  is pivotably attached to the housing  252  by a hinge element  266 , which may be a hinge or a piece of a flexible material. The cover  258  includes an elongated pressure element  260  disposed along its length and configured to contact a substantially central dorsal region of the hand along its longitudinal axis when the cover  258  is closed. The pressure element  260  may be composed of a rigid material, such as metal, wood, plastic or fiberglass, or it may be composed of a resilient material such as soft plastic, silicone gel, padding, foam, and a fluid or air-filled bladder, or a combination of one or more resilient and rigid materials. Referring now to FIG. 9, a different view of the apparatus  250  is shown.  
         [0044]    Referring back to FIG. 8, an optional releasable locking device  262 ,  264  may be positioned on the cover  258  and housing  252 , respectively to maintain the cover  258  in a locked position when it is closed over the hand. The locking device  262 ,  264  may be a clasp, a hook and loop combination (i.e. Velcro), a latch, or any other releasable retaining device.  
         [0045]    It should be noted that the individual elements shown in the various embodiments may be readily utilized in different embodiments or mixed without departing from the spirit of the invention. For example, the flexible cover  162  of the apparatus  150  of FIG. 6 may replace the rigid cover of the apparatus  10  of FIG. 1. In addition, the electronic device  40  illustrated in FIG. 2 may be incorporated into the various other embodiments. Furthermore, while cross sections of the various embodiments of the inventive apparatus are shown to be of rectangular or elliptical in shape, the cross section of the inventive apparatus may comprise any other geometrical shape without departing from the spirit of the invention.  
         [0046]    Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to preferred embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices and methods illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.