Abstract:
A scalpel enabling both safe blade engagement or disengagement and safe passing among personnel during surgical procedures. The scalpel is positionable in three configurations, including a blade shielded position, a blade exposed and operational position and a fully extended position for engagement and disengagement of the blade.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to surgical scalpels and, in particular, to surgical scalpels that have disposable, retractable and ejectable blades. 
       BACKGROUND 
       [0002]    Surgical scalpels are indispensable in the medical field. Numerous types of scalpels are available on the market. Desirable features in a surgical scalpel include safety, convenience of use, and cost. Surgery involves exposure to sharp objects, bodily fluids, and biomedical waste, and can be dangerous for a patient, the surgeon, and the surgery team. It is therefore desirable to have a scalpel that meets stringent occupational health and safety requirements. A scalpel should be designed for safe surgical contact with a patient. It is desirable that a scalpel be capable of being sterilized. It is also desirable that a scalpel blade be retractable and ejectable so that a user does not risk physical contact with the blade. An exposed blade can easily cut or prick someone and bring that person into contact with possibly contaminated or unsanitary material. Because a surgeon may not always have both hands available to handle a scalpel, it is also desirable that a retractable and ejectable scalpel be operable with one hand. Finally, it is desirable that a scalpel not need added lubricant. 
       SUMMARY 
       [0003]    This invention provides a retractable (or shieldable) and ejectable, disposable or replaceable-blade scalpel assembly that can be easily manipulated with one hand. A blade shield may be slid forward to cover the blade during periods of non-use or slid back to expose the blade for use. The movement can be accomplished with one hand with thumb pressure in the direction of the desired movement. It is common for surgical instruments to be passed between surgical personnel, and because the blade of this scalpel can be covered, the scalpel can be passed from one person to another without risk of contact with the blade. The scalpel&#39;s blade is also ejectable by use of thumb pressure in a forward-then-back pattern, to uncover the base of the blade, enabling the blade to be dropped from its position on the handle assembly into a proper receptacle. 
         [0004]    Embodiments of the scalpels of this invention permit the significant majority of all disposable scalpel blades to be engaged, concealed, and ejected without any physical contact between the user and the blade. 
         [0005]    Among other desirable features of some embodiments of this invention, movement of the blade shield between “blade exposed” and “blade covered” positions is accomplished with intuitively logical pressure on the button in the direction the shield must slide to cover or expose the blade as desired. By contrast, movement of the shield far enough distally on the handle to completely expose the blade for removal and replacement requires a slightly more complex and less intuitive application of force first to the button proximally until the shield moves a small distance proximally on the handle, further covering the blade, and then pressure must be applied distally to the shield (but not to the button) to slide the shield distally until the blade is released. Similarly, movement of the shield beyond the “safe passing,” “blade covered” position on the handle to entirely remove the shield and disassemble the scalpel requires a likewise somewhat more complex and less intuitive application of force. Force must be applied first to the button distally until the shield moves a small distance distally on the handle in the direction opposite that desired, and then pressure must be applied proximally to the shield (but not to the button) to slide the shield proximally until it disengages from the handle. While these sequences of application of pressure to replace the blade or disassemble the scalpel may be easily learned, use of each sequence tends to require intentional action, reducing the likelihood that blade disengagement or scalpel disassembly will be accomplished accidentally. 
         [0006]    The scalpels of this invention may be made, among other materials, of stainless steel and high-temperature resistant plastic. Use of these materials permit scalpel sterilization using both steam and chemical sterilization techniques, which protects patients while allowing the scalpel assembly to be reused, in contrast to disposable sterile scalpels that can only be used once. 
         [0007]    Scalpels of this invention are compatible with cleaning and sterilization protocol. 
         [0008]    Scalpels of this invention are ergonomic to help surgeons maintain proper control of the scalpel during use, and their geometry can provide excellent visualization around the proximal end of the scalpel. The construction of the scalpel is relatively light weight but has sufficient heft to feel familiar and appropriate to experienced surgeons. When engaged, the blade is locked firmly in place and facilitates firm incisions using the scalpel. Raised areas on the assembly components facilitate use and manipulation of the scalpel and its components without slipping. 
         [0009]    Scalpels of this invention also function without any need for lubricant, making them convenient and easy to maintain and use. 
         [0010]    The distal end of the scalpel of this invention is blunt to serve as a dissector or probe or aide to push tissue out of the way during surgery. 
         [0011]    These and numerous other features and benefits of the scalpels of this invention will become apparent by reference to the following descriptions and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of a disposable blade and scalpel assembly according to one embodiment of this invention, shown with the blade exposed. 
           [0013]      FIG. 2  is an exploded perspective view of the scalpel assembly shown in  FIG. 1 . 
           [0014]      FIG. 3  is a top view of the handle of the scalpel assembly shown in  FIG. 1 . 
           [0015]      FIG. 4  is a bottom view of the handle shown in  FIG. 3 . 
           [0016]      FIG. 5  is a perspective view of the bottom of the scalpel assembly shown in  FIG. 1 . 
           [0017]      FIG. 6  is a top view of the locking hold-down shown in  FIG. 2 . 
           [0018]      FIG. 7  is a bottom view of the locking hold-down shown in  FIG. 6 . 
           [0019]      FIG. 8  is a profile view of the locking hold-down shown in  FIG. 6 . 
           [0020]      FIG. 9  is a perspective view of the shield shown in  FIG. 1 . 
           [0021]      FIG. 10  is a top view of the shield shown in  FIG. 9 . 
           [0022]      FIG. 11  is a bottom view of the shield shown in  FIG. 9 . 
           [0023]      FIG. 12  is a perspective view of the blade of the scalpel assembly shown in  FIG. 1 . 
           [0024]      FIG. 13  is a perspective view of the locking hold-down shown in  FIG. 6 . 
           [0025]      FIG. 14  is a profile view of the scalpel assembly shown in  FIG. 1  with the blade covered. 
           [0026]      FIG. 15  is a profile view of the scalpel assembly shown in  FIG. 1  with the blade exposed. 
           [0027]      FIG. 16  is a profile view of the scalpel assembly shown in  FIG. 1  with the blade cover retracted so that the blade is disengaged. 
           [0028]      FIG. 17  is a bottom view of the scalpel assembly shown in  FIG. 1  with the blade exposed. 
           [0029]      FIG. 18  is a top view of the scalpel assembly shown in  FIG. 1  with the blade covered. 
           [0030]      FIG. 19  is a top view of the scalpel assembly of  FIG. 1  with the blade cover retracted so that the blade is disengaged. 
           [0031]      FIG. 20  is a bottom view of the scalpel assembly of  FIG. 1  with the blade covered. 
           [0032]      FIG. 21  is another bottom view of the scalpel assembly of  FIG. 1  with the blade exposed. 
           [0033]      FIG. 22  is a view, from the proximal end, of the handle shown in  FIG. 3 . 
           [0034]      FIG. 23  is a view, from the proximal end, of the shield shown in  FIG. 9 . 
           [0035]      FIG. 24  is a view, from the distal end, of the shield shown in  FIG. 9 . 
           [0036]      FIG. 25  is a profile view of the button shown in  FIG. 2 . 
           [0037]      FIG. 26  is a perspective view of the button shown in  FIG. 2 . 
           [0038]      FIG. 27  is an enlarged partial perspective view of the shield of  FIGS. 9 and 10 . 
           [0039]      FIG. 28  is an enlarged partial view of the shield and button of  FIG. 2 , with the button shown in cross section. 
           [0040]      FIGS. 29-32  illustrate various views of an alternative embodiment of a scalpel of this invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0041]    An exemplary scalpel assembly of this invention (illustrated in  FIG. 1 ) includes a handle  50 , a hold-down  60  (not shown), a shield  70 , and a button  80  and may be assembled with a standard scalpel blade  90 . 
         [0042]    As shown in  FIGS. 2-4 , the handle  50  may be an elongated bar that may be generally the same size as typical conventional scalpels with a proximal end  52  carrying a blade tang  584  and a blunt, distal or dissector end  54 . The hold-down  60  is seated within a hold-down recess  542  in the handle  50 , and the shield  70  partially surrounds and slides along the handle  50 , with travel limited by the function of the hold-down  60 , which is controlled by the button  80  sliding within a longitudinal slot or travel-way  76  in the shield. 
         [0043]    As will be appreciated by reference to  FIGS. 2 and 22 , handle  50  has a relatively thick middle portion  566  extending from the distal, dissector end  54  to the tang-carrying proximal end  52  to which the blade-receiving tang  584  is attached. As can be particularly well seen in  FIG. 22  the face  56  overlies the middle  566  of handle  50  at both the top  588  and bottom  589  of the handle, and the back  58  similarly extends beyond the middle  566  so that opposed grooves  598  and  599  are formed on the top  588  and bottom  589  of the handle  50  between face  56  and back  58 . 
         [0044]    Shield  70  generally lies against handle face  56  and has top and bottom edges  788  and  789  that extend around the top  588  and bottom  589  of handle face  56  and into the grooves  598  and  599 , thereby enabling shield  70  to be assembled onto handle  50  and, as described below, slide on handle  50  among “blade shielded,” “blade exposed” and “blade removal/replacement” positions. 
         [0045]    As is shown in  FIG. 11 , shield  70  edges  788  and  789  are joined by a shield bridge region  787  from which a shield tongue  72  extends distally so that the proximal end of shield  70  provides a sheath substantially surrounding blade  90  when shield  70  is in the “safety” or “blade shielded” position. 
         [0046]    As shown in  FIGS. 2 ,  3 ,  15  and  16 , blade-receiving tang  584  is configured to receive conventional disposable scalpel blades  90  and may have the same structure as the tang described in published Scalpel Assembly patent application PCT/IB00/00426, WO 00/61014, which is incorporated herein by reference. When a disposable blade  90  (shown in  FIGS. 12 ,  15 ,  16  and  19  for example) is positioned on tang  584  and the distal end  93  of blade  90  is forced or retained against face  65 , the blade  90  will be secured to the tang  584  and cannot be removed by any of the forces or movements that occur during normal surgical use of the scalpel assembly  10  (not referenced on figure). Removal of the force or structure retaining the distal end  93  against face  65  allows blade  90  to be disengaged from tang  584  and removed or dropped off of handle  50 . 
         [0047]    Tang  584  may alternatively have any other structure that will receive and securely hold conventional replaceable surgical blades by application of force to the distal blade end  93  normal to one of the blade sides or otherwise preventing movement of distal blade end  93  so that blade  90  will not move relative to or detach from tang  584  or other structure for receiving and holding blade  90 . Such alternative tangs typically have a protrusion that will pass through the broader, distal end of the slot in conventional blades, with a narrower waist or base supporting the protrusion so that the blade can be moved distally until the protrusion is positioned above the narrower, proximal end of the blade slot. 
         [0048]    Hold-down  60  cooperates with the other components of handle  50  to retain blade  90  on tang  584  and lock shield  70  in either a blade-covered position (as illustrated in  FIG. 18 ) or a blade-exposed position (as illustrated in  FIG. 17 ). 
         [0049]    Hold-down  60  is positioned within a hold-down recess  542  in handle  50 , shown in  FIGS. 2 and 3 . Recess  542  is an elongated depression of sufficient depth to receive and retain hold-down  60  with only two portions extending or extendable above the plane of handle face  56 : (1) a pin or projection  62  on the distal end of hold-down  60  and (2) a blade retaining bar  64  on the proximal end of the hold-down  60 . Interaction between shield  70  and each of blade hold-down arms  642  and projection  62 , enables function of the handle assembly  50 . Recess  542  in handle  50  may be penetrated by cleaning holes  544  to permit entry of steam or other fluids during disinfecting, cleaning and sterilization. 
         [0050]    While numerous other structures and materials may be used for hold-down  60 , the embodiment illustrated in the figures may be fabricated from a single piece of precipitation hardenable stainless steel,  400  or  300  series family with two working ends. On its proximal end, hold-down  60  provides a blade retaining bar  64  for contact with the distal blade end  93 . Bar  64  is supported in the illustrated embodiment by arms  642  that attach to resistance arms  682  surrounding a hold-down head  63  penetrated by a rivet hole  66 . When the components are assembled, rivet hole  66  is positioned on a rivet pin  548  protruding from an up-standing hold-down stand or promontory  546 . Stand  546  also includes an optional proximally-facing bracket or centering hold-down limiter  550 . 
         [0051]    Hold-down  60  also provides a distal end pin or projection  62  formed at an end of the bar  63  structure by a flex arm  628  configured to urge projection  62  upward out of recess  552  and against shield  70  and button  80 . A distally-facing tang  622  protruding from the base of projection  62  is received in a recess  590  in handle  50  that defines a lip  592  that overlies tang  622  and thereby limits movement of projection  62  out of recess  552 . This recess  590  can be provided by forming a flat-bottom cleaning hole that does not quite penetrate face  56 . 
         [0052]    As shown in  FIG. 4 , the back  58  of the handle  50  includes handle grips  522  extending from the proximal end of the back  58  to nearly the midpoint of the back  58 . In the embodiment shown in the figures, the handle grips  522  are a series of raised bumps surrounded by a surface below the bottom face  58 , so that the tops of the grips are at least approximately even with the back  58 . 
         [0053]    As is illustrated in  FIGS. 1 ,  14 - 19 , and  25 - 28 , an elongated sliding component or button  80  is attached to and slides along a portion of the face  77  of shield  70 . Details of one embodiment of the button  80  and portions of the shield  70  are illustrated in  FIGS. 26-28 . Portions of button  80  have a cross-sectional shape similar to an I-beam where the button face or “top flange”  804  lies against the shield face  77  and is attached by an interconnecting “web”  806  (positioned within a longitudinally-extending slot or travel-way  76  in the shield  70 ) to a narrower lower face or “bottom flange”  808 . 
         [0054]    The button  80  includes a plurality of lateral ridges  82 . In one embodiment, the lateral ridge on each end of the button is a longer ridge  84 . The top surface also includes a long ridge  86  positioned longitudinally. In an alternative embodiment, shown for example in  FIGS. 29-32 , the ridges are curved, and may include curved arrowhead shapes pointing in the direction of the slide. 
         [0055]    The web  806  of the button  80  engages the side walls  784  and  786  of travel-way  76  to lock the button into the travel-way  76 . Detent recesses  821 ,  822 ,  823 , and  824 , along the web  806  of button  80  engage protrusions  780  and  782  at either the “blade exposed” or “blade shielded” configuration to reduce the likelihood that button  80  will slip out of position. Cut outs  825  and  826  at the midpoint of bottom plate  808  allow the button to snap into travel-way  76  over protrusions  780  and  782 . 
         [0056]    Shield  70  is penetrated by transverse detent slots  770  and  774  that can receive projection  62  of locking hold-down  60  when shield  70  is positioned on the handle  50  with one or the other of detent slots  770  or  774  aligned with projection  62  and with button  80  clear of the slot. As either detent slot  770  or  774  aligns with projection  62  the flex arm  628  forces projection  62  upward, creating an audible “click” as projection  62  rises into detent slot  770  or  774 , locking the shield  70  in place. Sliding button  80  toward the proximal end of shield  70  covers detent slot  770  pushing projection  62  out of slot  770  (or preventing entry of projection  62  into slot  770  if it is not already in it). Sliding button  80  toward the distal end of shield  70  likewise covers detent slot  774 , pushing projection  62  out of, or preventing projection  62  from entering, detent slot  774 . 
         [0057]    Travel way  76  has a centrally located travel-way stop  768  formed by protrusions  780  and  782  in the side walls  784  and  786  of travel-way  76 . The web  806  of the button  80  engages the side walls  784  and  786  to releasably lock the button in desired positions along the travel-way  76 . Detent recesses  821 ,  822 ,  823 , and  824 , along the web  806  of button  80  engage protrusions  780  and  782  at either the “blade exposed” or “blade shielded” configuration to prevent the button  80  from slipping out of position. With protrusions  780  and  782  received in recesses  821  and  822 , button  80  is held at an extreme of travel within travel-way  76 . With protrusions  780  and  782  received in recesses  823  and  824 , button  80  is held at the other extreme of travel within travel-way  76 . Gaps  825  and  826  in bottom plate  808  of button  80  are aligned over and receive stops  780  and  782  when button  80  is assembled to shield  70 . 
         [0058]    Shield  70  is illustrated in  FIGS. 9-11 . As noted above, shield  70  generally lies against handle face  56  and has external top and bottom edges  788  and  789  that extend around the top  588  and bottom  589  of handle face  56  and into the grooves  598  and  599  of handle  50 , thereby enabling shield  70  to be assembled onto handle  50  and to slide on handle  50  among “blade shielded,” “blade exposed” and “blade removal/replacement” positions. 
         [0059]    The shield  70  has a generally rectangular but relatively complex cross-sectional shape. A face  77  is equal in width to the width of the handle  50  back  58  and, in the embodiment illustrated in  FIGS. 14-16 , about two-thirds of the length of the handle  50 . Face  77  has projecting “bumps” or grips  748  near its proximal end, and a centrally positioned longitudinal travel-way  76  near its distal end. A bridge  787  connects edges  788  and  789  at the proximal end of shield  70  and supports a shield tongue  72  that extends distally from the bridge  787 . This bridge  787  permits shield  70  to entirely encircle handle  50  at the shield  70  proximal end, and bridge  787  and tongue  72  (together with a proximal portion of the face  77  of shield  70 ) substantially cover blade  90  when shield  70  is in its proximal, “blade shielded” position on handle  50  (as illustrated in  FIG. 20 ). Tongue  72  slides into a tongue recess  524  in handle  50  when shield  70  is in its retracted, blade exposed position, and tongue  72  fully occupies tongue recess  524  when shield  70  is in the blade removal/replacement position illustrated in  FIGS. 16 and 19 . This configuration provides shield structure on the back of the assembly  10  long enough to substantially cover blade  90  when shield  70  is in the blade covered position while not preventing contact between a user&#39;s hand and relatively proximal region of handle  50  in the blade exposed configuration. 
         [0060]    The lower, proximal corner  746  of the shield  70  is “eased” or removed to provide unobstructed access to blade  90 . The shield grips  748  are defined by removing or omitting adjacent material to establish a surrounding surface below that of shield  70  face  77  around travel-way  76  and the region of face  77  at the proximal end of the shield  70 . These grips facilitate sliding shield  70 , and lateral ridges  82  on button  80  facilitate application of thumb pressure to button  80  and rise above the shield grips  748 , thereby providing a differential tactile response to a user, confirming location of the user&#39;s thumb on one or the other of the button  80  or shield  70  grips  748 . A distal promontory  772  that rises above shield face  77  to the same plane as lateral ridges  82  provides a tactilely continuous structure when the button abuts the promontory  772 . Alternatively, when button  80  is positioned proximally on the shield  70 , promontory  772  provides a structure against which thumb pressure can be exerted to slide shield  70  to its most distal, blade-ejecting and -replacement position. In addition, promontory  772  gives added strength to the shield  70  and accommodates inner face  778 . The inner face  778  of shield  70  under promontory  772  slopes to facilitate assembly of shield  70  onto handle  50 . 
         [0061]    Assembly of the exemplary scalpel components of this invention illustrated in the figures is accomplished by positioning button  80  in travel-way  76 , positioning locking hold-down  60  in handle  50  recess  542  with rivet pin  548  in rivet hole  66  (compressing hold-down arms  642 ) and sliding shield  70  onto the proximal end  52  of handle  50  until hold-down projection  62  seats in one of the detent slots  770  or  774  in shield  70 . 
         [0062]    While holding button  80  in its most proximal position, force is applied distally to shield  70 , causing shield  70  to slide as far distally on handle  50  as it is capable of moving. Continued distal force against shield  70  while maintaining a proximal force on button  80  slides shield  70  to the fully extended blade position. This also exposes hold-down  64 , allowing hold-down  64  to lift enough to release the distal end  93  of blade  90 , allowing it to fall off tang  584 . A new blade  90  can then be placed on and held in position on tang  584  while shield  70  is slid proximally on handle  50  until hold down  64  is pressed down by the proximal end of shield  70 , and projection  62  is received in detent slot  770  (for use with the blade  90  exposed) or in detent slot  774  (for safe passing with the blade  90  covered). 
         [0063]    The blade  90  can be alternatively covered for safe passing or exposed for safe use by application of force, typically with the user&#39;s thumb, on the button  80 , first, to slide the button  80  within the travel-way  76  and relative to the shield  70  and then to slide the button  80  and shield  70  together until the locking hold-down  60  projection  62  seats in one or the other of the detent slots  770  and  774 . Because of the tactile features on the scalpel  10  components and the audible “click” that occurs when the projection  62  seats in a detent slot  770  or  774 , a user can very quickly learn to manipulate the shield without looking at the scalpel. 
         [0064]    The scalpel assembly of this invention can be produced in numerous alternative embodiments. In other embodiments the hold-down  60  need not be a continuous structure. The projection  62  may be spring loaded, or forced upward by a resistance arm, independent of the hold-down arms  642  and the flex arm  628 . The projection  62  also need not travel normal to face  56  and button  80 . Other embodiments, for instance may feature a projection that moves parallel to face  56  and/or button  80 . The important feature is that the shield  70  locks at two different locations ( 770  and  774  in the embodiment above). 
         [0065]    Another embodiment may locate the blade  90  on the back  58  of the handle, in which case the hold-down arms  642  would have to pull the blade against back  58  or another surface. 
         [0066]    Other embodiments may include two stationary buttons instead of one slidable button  80 . A separate button at each detent slot  770  and  774  could be able to both receive and disengage projection  62 . The user could then apply a force (distally or proximally) and slidably move the shield  70  to a desired position. 
         [0067]    Another embodiment may associate projection  62  with detent slot  774  at the blade exposed position, and with detent slot  770  at the blade covered position. 
         [0068]    Handle  50  may be machined, molded, forged, cast or otherwise manufactured of steel, stainless steel, high temperature and chemical-resistant plastic such as PEK (poly-ether-ketone), PEEK (poly-ether-ether-ketone) or PEKK (poly-ether-ketone-ketone), or composites of these materials or of any other material using any other technique that results in a handle having acceptable characteristics of strength, rigidity, heft, durability, sterilizability, and cleanability. 
         [0069]    Button  80  and shield  70  likewise may be machined, molded, forged, cast or otherwise manufactured of steel, stainless steel, high temperature and chemical-resistant plastic such as PEK (poly-ether-ketone), PEEK (poly-ether-ether-ketone) or PEKK (poly-ether-ketone-ketone) or of any other material using any other technique that results in a handle having acceptable characteristics of strength, rigidity, heft, durability, sterilizability, and cleanability. While not indispensable, it is desirable that one or both of buttons  80  and shield  70 , and of shield  70  and handle  50  have properties of lubricity to facilitate sliding contact without the need for additional lubrication. 
         [0070]    Locking hold-down  60 , or components providing the function of locking hold-down  60 , may be fabricated from a similar range of materials utilizing a similar range of techniques provided that such manufacture achieves adequate properties of springiness, resistance, strength, durability, cleanability, sterilizability and the like. 
         [0071]    As should be apparent from the foregoing description of this invention and alternative structures, manufacturing techniques, and materials, this invention is not limited by such exemplary embodiments but includes all variations and alternative embodiments within the scope and spirit of the foregoing description, the accompanying drawings, and the following claims.