Abstract:
A scalpel ( 10 ) having a handle assembly ( 16 ) and one of a plurality of modular blade assemblies ( 18 ). Each blade assembly includes a casing ( 46 ) within which is a retractable rod ( 48 ) having a distal end to which is permanently affixed a blade ( 12 ), and also includes a spring ( 56 ) having an unstressed state wherein the retractable rod and its blade are retracted within the casing. The handle assembly ( 16 ) includes a handle casing ( 20 ) within which is slidably disposed a handle rod ( 32 ) that is manipulatable between a retracted position and an active position with respect to the handle casing. In the active position, the handle rod&#39;s distal end engages and pushes the proximal end ( 66 ) of the retractable rod ( 48 ) to urge the blade ( 12 ) distally for performance of a procedure, while in the retracted position, the handle rod ( 32 ) permits the retractable rod ( 48 ) to self-retract within its casing ( 46 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. Provisional Patent Application Ser. No. 61/280,399 filed Nov. 4, 2009. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This relates to the field of medical devices and more particularly to scalpels. 
       BACKGROUND OF THE INVENTION 
       [0003]    In ophthalmic surgery, and in neurosurgery, intricate incisions must often be made on tissue surfaces that are not planar, e.g., on spherical surfaces such as the eye. This requires the use of fine, precision blades such as diamond blades that have cutting edges of different designs to attain subtly different incisions. Cutting edges and their resultant incisions are disclosed, for example, in U.S. Pat. No. 5,713,915. Scalpel instruments to which such diamond blades are affixed are also known. 
         [0004]    Certain scalpels are known in which the blade tip is retractable into the scalpel&#39;s distal end for safety reasons; for precision diamond blades, retraction of the blade importantly serves to protect the extremely fragile blade. See U.S. Pat. Nos. 5,342,379 and 5,431,671, wherein the blade is retractable by a spring, and U.S. Pat. No. 5,665,099, wherein the blade is retractable by a vacuum. U.S. Pat. No. 6,884,240 discloses a slidable guard that is movable distally to a locked position to surround and enclose the blade. In U.S. Pat. No. 6,544,277, a scalpel is disclosed wherein a common handle is adapted to receive one of a plurality of blade assemblies disconnectable therefrom, enabling a surgeon to select a blade assembly having the desired blade design. The patent also discloses a plurality of blade cutting edge designs. 
         [0005]    It is desired to provide a scalpel assembly wherein a plurality of blade assemblies are each adapted to be easily and quickly connected to and released from a common handle by the surgeon during a procedure, and wherein the blade tip is retractable into the scalpel assembly&#39;s distal end by the surgeon when desired. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    Briefly, the present invention is a modular scalpel assembly, wherein a handle assembly is adapted to receive affixable thereonto one of a plurality of blade assemblies that are distinguished from each other by the particular blade design or size, or both, and wherein the blade is retractable into its blade assembly for safety and blade protection purposes. The retraction is achieved by a handle rod that is slidable between a first and a second position within its handle casing, with its first or active position forcing the blade from the blade assembly casing for performance of surgery, and with its second or retracted position permitting the blade to self-retract within the blade assembly&#39;s casing. 
         [0007]    In the preferred embodiment, the blade assembly comprises a blade assembly casing within which is secured a retractable rod having a distal end whereonto is permanently affixed a blade, and having a proximal end engageable and cooperable with the handle rod of the handle assembly. Preferably, the retractable rod is movably secured within the blade assembly casing by an inner collar of the casing; a first fitting is affixed to the retractable rod near a distal end thereof that abuts the inner collar from distally thereof; a second fitting is affixed to the retractable rod at a proximal end thereof; and a compression spring is disposed about a portion of the retractable rod, held between the second or proximal fitting and the inner collar of the casing. 
         [0008]    Also, in the preferred embodiment, the handle assembly comprising the handle casing and the handle rod defines an arrangement for relative axial positioning of the handle rod with respect to the handle casing, the preferred arrangement comprising an axially extending slot defined in the handle casing having distal and proximal ends whereat doglegs extend radially to define first and second detents, for active and retracted states of the scalpel, in cooperation with a radially outward pin of the handle rod that is disposed within the axially extending slot upon assembly. 
         [0009]    Such a modular scalpel assembly permits easy assembly of the handle assembly and a selected one of the blade assemblies, such as by using male and female threaded connection sections of the respective casings at the connection interface, that permit the open proximal end of the blade assembly to allow access thereto and engagement by the retractable rod&#39;s proximal end and the distal end of the handle rod that will urge the retractable rod distally into an active state wherein the blade is exposed for use in surgery. The modular scalpel assembly is easily sterilizable for reuse, and includes a plurality of blade assemblies each having a blade, preferably a diamond, having a particular design to achieve a particular kind of cut, and is especially useful in ophthalmic surgery, neurosurgery and the like, wherein precision cuts of subtle but distinct shapes are essential. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate the presently preferred embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain the features of the invention. In the drawings: 
           [0011]      FIG. 1  is a plan view of a scalpel assembly of the present invention, with its blade extended for use; 
           [0012]      FIG. 2  is a plan view of the scalpel assembly of  FIG. 1  with the handle assembly exploded from the blade assembly, in a first or active state wherein the handle rod distal end protrudes from the distal end of the handle casing, and the blade affixed to the retractable rod is shown projecting from the blade assembly casing; 
           [0013]      FIG. 3  is a plan view of the scalpel assembly of  FIG. 1  with the handle assembly exploded from the blade assembly, in a second or retracted state wherein the handle rod distal end is recessed within the distal end of the handle casing, and the blade affixed to the retractable rod is recessed within the blade assembly casing; 
           [0014]      FIG. 4  is an exploded view of the components of the retractable rod and its related components; 
           [0015]      FIG. 5  is a cross-sectional view of the blade assembly casing, with its inner collar discernible near its distal end; 
           [0016]      FIG. 6  is a cross-sectional view of the blade assembly as assembled, with the blade shown recessed within the distal end of the blade assembly casing, and the spring disposed between the proximal fitting and the inner collar in a substantially unstressed state; 
           [0017]      FIG. 7  is a plan view of the scalpel assembly displayed in a tray such as for sterilization, showing the handle assembly and a plurality of representative blade assemblies each having a blade with a different design of cutting edge from the others; and 
           [0018]      FIG. 8  illustrates a plurality of diamond blades having respectively different designs of cutting edges, or different sizes. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    In the drawings, like numerals indicate like elements throughout. Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. The terms “distal” and “proximal” refer, respectively, to directions closer to and away from a patient for a procedure. The terminology includes the words specifically mentioned, derivatives thereof and words of similar import. The terms and expressions used herein, and the embodiments illustrated below, are not intended to be exhaustive or to limit the invention to the precise form disclosed. These terms, expressions and embodiments are chosen and described to best explain the principle of the invention and its application and practical use and to enable others skilled in the art to best utilize the invention. 
         [0020]    Scalpel  10  of the present invention is shown in  FIG. 1  in an active state with the blade  12  extended distally and having a cutting edge  14 , for performance of surgery by the surgeon. The scalpel  10  is an assembly basically of a handle assembly  16  to which is connected a blade assembly  18  at the distal end of the handle assembly. Blade  12  is mounted to a blade mount section  22  protruding distally from blade assembly distal end  24  for use. Handle assembly  16  includes a tubular handle casing  20  within which is disposed a cylindrical handle rod  32 , with handle rod  32  being manipulated by its proximal end  24  which has preferably a knurled surface  28  to facilitate gripping by the surgeon. Other knurled surfaces  28  are preferably provided on handle casing  20  and blade assembly casing  46  for the same purpose. 
         [0021]    In  FIGS. 2 and 3  are shown the handle assembly  16  and the blade assembly  18  separated from each other, with  FIG. 2  showing the assemblies as if in the active state in which the blade  12  would protrude from the distal end of the blade assembly  18 , while  FIG. 3  shows the assemblies as if in the retracted state in which the blade  12  would be recessed within the distal end of the blade assembly  18 . It is seen that the blade assembly  18  includes a proximal male threaded section  40  for coupling with and decoupling from a distal female threaded section  36  of the handle assembly  16 . Abutment of the proximal end  42  of blade assembly casing  46  with the distal end  34  of the handle casing  20  indicates when the two assemblies are fully coupled. It should be noted that the handle rod  32  includes a distal end portion that projects distally from the handle casing  20  when in the active state, for cooperating with the retractable rod of the blade assembly to urge it distally against spring bias to translate the blade mount section  22  distally for blade  12  to be exposed for surgical use. 
         [0022]    Referring now to  FIGS. 4 to 6 , blade assembly  18  is shown in detail, having a cylindrical retractable rod  48  disposed movably within tubular blade assembly casing  46 , with a coil spring  56  disposed about the retractable rod  48 . Thin diamond blade  12  is affixable into slot  62  into the blade mount section  22  of the retractable rod  48  such as epoxy resin; preferably, small radial holes  64  into the blade mount section  22  permit wicking of the epoxy resin thereinto from the base of slot  62  and form mechanical joints with the retractable rod. A proximal fitting  58  is shown that is force fit, for example, onto the proximal end of retractable rod  48  to define a proximal stop for the proximal end  72  of spring  56 . A distal fitting  60  is shown that is force fit, for example, onto the retractable rod  48  just proximally of the blade mount section  22 . Blade assembly casing  46  includes defined therewithin an inner collar  54 : the inner collar serves as the distal stop for distal end  70  of spring  56  and also as the proximal stop for distal fitting  60 . Upon assembly, the retractable rod subassembly is secured within the blade assembly casing by its distal fitting  60  being distal of the inner collar  54 , and the trapped spring  56  being proximal of the inner collar  54 , all allowing the retractable rod  48  being axially movable within the blade assembly casing  46 . Trapped spring  56  is biasable upon engagement of the distal end of handle rod  32  abutting and pressing distally the proximal end  66  of retractable rod  48 , which causes the blade mount section  22  and the blade  12  to protrude distally from the distal end of the blade assembly casing  46 . Preferably, the handle rod  32  includes a rib  38  receivable into a complementary slot  68  into the proximal end  66  of retractable rod  48  enabling rotation of the retractable rod  48  by handle rod  32 , as will be explained hereinbelow. 
         [0023]    Referring again to  FIGS. 1 to 3 , a pin-and-slot arrangement  26  in the handle assembly  16  is shown which is utilized to control retraction and projection of the blade from the scalpel. Handle casing  20  is cylindrical and a slot  76  is defined through the wall of the handle casing generally extending in an axial direction, with a distal dogleg portion  78 , 84  and a proximal dogleg portion  80 , 86 . A pin  82  projecting radially from the side of handle rod  32  is disposed within the slot  76  and movable therealong between the distal and proximal dogleg portions. Movement of the pin along transverse dogleg portions  84 , 86  is attained by incremental rotation of the handle rod with respect to the handle casing  20 . Seating within the axial portions of the dogleg portions is assured by the handle rod  32  being continuously biased proximally by the force of the spring about the retractable rod within the blade assembly  18 . 
         [0024]    Assembly and operation of the scalpel is easily performed by the surgeon. A particular blade assembly is selected by the surgeon according to the type of incision needed; the selected blade assembly is threadedly coupled to the handle assembly, during which the distal end of the handle rod  32  (in its “active” state) engages the proximal end  66  of the retractable rod with the rib  38  becoming assuredly seated in the complementary slot  68  by incremental rotation of the blade assembly, all while the spring  56  is being compressed; and, the pin  82  of the handle rod becomes seated within distal dogleg portion  78  by reason of the stored energy of the spring  56  urging the handle rod proximally, whereby the scalpel is locked in the active state. 
         [0025]    Retraction of the blade  12  into the blade assembly  18  is achieved simply by urging the handle rod  32  distally against spring bias to align the pin radially with transverse dogleg portion  84  and then rotating the handle rod  32  with respect to the handle casing  20  until the pin  82  is aligned with the main axially extending portion of the slot  76 , whereupon the stored energy of the spring  56  urges the handle rod proximally until reaching axial portion  86  of proximal dogleg portion  80 , whereupon the blade mount section  22  and blade  12  self-retract into blade assembly casing  46 ; and, finally, incremental rotation of handle rod  32  enables assured seating of the pin  82  within proximal dogleg portion  80  by reason of stored energy of spring  56 , locking the scalpel into the retracted state wherein the blade is withdrawn into the blade assembly casing  46 . Preferably, the handle rod  32  remains in engagement with the retractable rod  48  at all times while the handle and blade assemblies are connected, as a result of continuous spring bias. Continuous engagement of the handle and blade assemblies is assured by the continuous spring bias, which in turn assures a smooth transition between active and retracted states. Disassembly of the blade assembly  18  from the handle assembly  16  is easily achieved by retracting the blade into the blade assembly as just described, until the pin becomes seated at the proximal end of the axially extending slot portion  76 , whereupon the blade assembly can be unthreaded and disconnected from the handle assembly. 
         [0026]    Preferably, the components of at least the handle and retractable rods, and the handle and blade assembly casings are precision machined of a durable, light-weight metal such as titanium. It is preferred that the rods fit snugly within their respective casings to minimize lateral play while also minimizing any friction between the adjacent surfaces during axial movement. It is also preferred that, for the performance of very precise surgery, the blade be a diamond. The assembly is free of lateral projections, and the pin of the handle rod, preferably, does not project beyond the outer surface of the handle casing at the slot. 
         [0027]      FIG. 7  is representative of a scalpel kit wherein the handle assembly  16  and a plurality of representative blade assemblies  18  are positioned within a tray  100 , with the tray preferably permitting sterilization of the kit. An array of blades  12 A to  12 G with representative distinct designs of blade tips  14 A to  14 G is shown in  FIG. 8 , with each blade tip so designed to be utilizable to result in different resultant incisions, as desired by the surgeon; the blade assemblies are held in the active state by portions of the tray (not shown) in order for the blades to be assuredly sterilized. Also, the blades may be of different sizes. At this time, it is estimated that there presently are over fifty different blade designs and sizes in use by surgeons world-wide. 
         [0028]    It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.