Abstract:
A dual bladed surgical saw and method of use. Two blade assemblies are attached to a saw body. Each blade assembly includes an oscillator driving a blade, and teeth on each blade. The blades are disposed at a pre-determined blade angle relative to each other, thus allowing two cuts to be made simultaneously and independently at the blade angle relative to each other. The blade assemblies may be rotatable relative to each other, which allows the pre-set blade angle to be varied appropriate to the procedure contemplated. One embodiment uses a slotted protractor bearing protractor indicia, and a threaded fastener to set the blade angle. Another embodiment uses shims between blade assembly arms to quickly and accurately set the blade angle. Method steps include pre-setting the blade angle, and making two cuts simultaneously at an angle relative to each other equal to the blade angle.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to surgical saws, and in particular to a dual bladed surgical saw and method of use. 
     2. Background of the Invention 
     Certain surgical procedures require bone cuts at precise angles. For example, the most common bunion surgical procedure is the Austin bunionectomy, also known as the Chevron bunionectomy. 
     The Austin bunionectomy procedure requires cutting a sixty degree angled cut into the first metatarsal head. The two resultant sections of the first metatarsal head are translated sideways, and then fixated. Fixation may be accomplished with a K-wire, pin, or other appropriate fixation device. Protruding sections of bone are cut off as appropriate, and a wedge may be removed from the first phalange as necessary. After the bones involved are aligned properly, they may be fixated with pins, screws, staples, etc., as appropriate. 
     The optimal angle at which to make the Austin bunionectomy angle cut is sixty degrees, that is to say, two cuts disposed at sixty degrees to each other. More than sixty degrees results in a loss of stability, while with less than sixty degrees one gets into the spike area, and healing surface area is sacrificed. Therefore it is important to achieve a sixty degree bone cut for best results from the procedure. 
     Existing Designs. 
     Currently, a first cut is made, and then a guide, which could be a guide wire, is used to make the second cut. This procedure is less than ideal, because it is time-consuming and not extremely accurate. Thus, it would be desirable to provide a dual bladed surgical saw whose two blades simultaneously make a pair of cuts at sixty degrees relative to each other. This ability would improve efficientcy as well as accuracy. 
     Further, it would be desirable to be able to vary the angle between the two blades, in order to make other bone cuts necessary during surgery. For instance, it would be helpful to be able to make two bone cuts simultaneously to isolate a bone wedge for removal. Such cuts typically require a pair of bone cuts at an angle of ten to thirty degrees relative to each other. 
     Other angled bone cuts which would benefit from a dual bladed surgical saw include hand procedures. It would be beneficial to provide a dual bladed surgical saw whose blades could be pre-set to the correct angle for the procedure, and then both cuts made simultaneously and independently by the two blades at precisely the correct angle. 
     It would also be desirable to be able to remove one blade from the dual bladed surgical saw to leave only one blade. This blade could be used conventionally for cuts where only one blade is required. 
     A number of dual bladed surgical saws have been proposed. U.S. Pat. Nos. 7,744,616 and 6,007,541, Publication No. 2011/0230887, and Statutory Invention Registration H571 by O&#39;Donoghue, Scott, Bickenbach, and Hollinger et al. respectively, all described saws having two blades. These designs all taught two parallel blades, with no provision for changing the angle between them. Thus, these would not be able to make the sixty degree cuts required during Austin bunionectomies, nor the ten to thirty degree angled cuts required for bone wedge removal, nor the other angled cuts required by other procedures. 
     U.S. Pat. No. 6,860,886 was granted Lee for a reciprocating surgical saw having a single blade whose angle relative to the handle was adjustable. While this design disclosed angular adjustability of the single blade, it did not disclose a single saw having two blades, nor adjustability of the angle between the two blades. Thus, the Lee device would not serve to make the sixty degree cuts required during Austin bunionectomies, nor the ten to thirty degree angled cuts required for bone wedge removal, nor the other angled cuts required by other procedures. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a dual bladed surgical saw and method of use which is capable of simultaneously making two cuts at a pre-determined angle. Design features allowing this object to be accomplished include a saw body having a switch which actuates a first oscillator and a second oscillator, a saw blade attached to each oscillator, and a blade angle between the saw blades. Advantages associated with the accomplishment of this object include increased accuracy and efficiency in the surgical procedure. 
     It is another object of the present invention to provide a dual bladed surgical saw and method of use which is capable of simultaneously making two cuts at a pre-determined angle, which angle may be varied prior to making the cuts. Design features allowing this object to be accomplished include a saw body having a switch which actuates a first oscillator and a second oscillator which are part of a first blade assembly and a second blade assembly, a rotatable attachment between the two blade assemblies, a saw blade attached to each oscillator, an arm attached to each blade assembly, and a protractor or shims between the arms. Benefits associated with the accomplishment of this object include the ability to pre-set an angle between the cuts made by the blades to suit the specific surgical procedure being performed, increased accuracy and improved efficiency. 
     It is still another object of this invention to provide a dual bladed surgical saw and method of use which permits the removal of one blade assembly. Design features enabling the accomplishment of this object include a first blade assembly rotatably attached to a second blade assembly. An advantage associated with the realization of this object is the ability to remove the first blade assembly and use the surgical saw with only one blade, thus increasing the versatility and ease of use of the dual bladed surgical saw. 
     It is yet another object of this invention to provide a dual bladed surgical saw and method of use which is inexpensive to produce. Design features allowing this object to be achieved include the use of commercially available components. Benefits associated with reaching this objective include reduced cost, and hence increased availability. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention, together with the other objects, features, aspects and advantages thereof will be more clearly understood from the following in conjunction with the accompanying drawings. 
       Six sheets of drawings are provided. Sheet one contains  FIG. 1 . Sheet two contains  FIG. 2 . Sheet three contains  FIGS. 3 and 4 . Sheet four contains  FIG. 5 . Sheet five contains  FIG. 6 . Sheet six contains  FIGS. 7-9 . 
         FIG. 1  is a right side isometric view of a dual bladed surgical saw. 
         FIG. 2  is a rear isometric view of a dual bladed surgical saw. 
         FIG. 3  is a right side isometric view of a dual bladed surgical saw with a protractor being used to set the angle between the blades. 
         FIG. 4  is a side cross-sectional view of a fastener, protractor, and second blade assembly arm taken at section IV-IV of  FIG. 3 . 
         FIG. 5  is a right side isometric view of a dual bladed surgical saw with shims being used to set the angle between the blades. 
         FIG. 6  is a right quarter side isometric view of a dual bladed surgical saw with one blade assembly removed. 
         FIGS. 7-9  depict the method of use for a dual bladed surgical saw. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to  FIG. 1 , we observe a right side isometric view of dual bladed surgical saw  2 . Dual bladed surgical saw  2  incorporates first blade assembly  10  and second blade assembly  20  attached to saw body  4 . First blade assembly  10  includes first blade  14  attached to first oscillator  12  at one end, and has saw teeth  16  at the other. Second blade assembly  20  includes second blade  24  attached to second oscillator  22  at one end, and has saw teeth  16  at the other. 
     In the example illustrated in  FIG. 1 , saw body  4  is an electric saw body with battery  6  connected to first blade assembly  10  and second blade assembly  20  through switch  8 . When switch  8  is closed, first oscillator  12  and second oscillator  22  oscillate, which in turn cause first blade  14  and second blade  24  to reciprocate as indicated by arrows  50  and  52 . While some of the figures herein depict electric saw bodies  4 , it is intended to fall within the scope of this disclosure that any appropriate saw body and oscillators be used, including electric, pneumatic, etc. 
     First blade  14  and second blade  24  are disposed at blade angle  30  relative to each other. In the embodiment dual bladed surgical saw  2  depicted in  FIG. 1 , blade angle  30  is fixed at a pre-determined value. This may be desirable where dual bladed surgical saw  2  is used for a single procedure, or group of procedures, which require the same cut angle. For example, if dual bladed surgical saw  2  is to be used solely for Austin bunionectomies, blade angle  30  would be fixed at sixty degrees during the manufacturing of dual bladed surgical saw  2 . If it is desired to be able to vary blade angle  30 , alternate embodiments of dual bladed surgical saw  2  with that capability are disclosed herein, and are described below in connection with  FIGS. 3-5 . 
       FIG. 2  is a rear isometric view of an alternate embodiment dual bladed surgical saw  2 . The dual bladed surgical saw  2  depicted in  FIG. 2  includes a blade angle  30  between first blade  14  and second blade  24  which is fixed. First oscillator  12  drives first blade  14 , and second oscillator  22  drives second blade  24  as indicated by arrows  54  and  56 . 
       FIG. 3  is a right side isometric view of a variable blade angle  30  dual bladed surgical saw  2  with protractor  15  being used to set the blade angle  30  between first blade  14  and second blade  24 . First blade assembly arm  11  is attached to, and extends from, first blade assembly  10 . Second blade assembly arm  21  is attached to, and extends from, second blade assembly  20 . Protractor  15  is shaped substantially as an arc of a circle, and as attached at one end to first blade assembly arm  11 . Protractor  15  includes protractor slot  17  disposed along the length of protractor  15 . Protractor slot  17  is also shaped substantially as an arc of a circle. 
       FIG. 4  is a side cross-sectional view of fastener  18 , protractor  15 , and second blade assembly arm  21  taken at section IV-IV of  FIG. 3 . Fastener  18  has fastener threaded stud  19 , and serves to releasably fix the position of protractor  15  relative to second blade assembly arm  21 . Second blade assembly arm  21  incorporates second blade assembly arm threaded bore  23 , sized to mate with fastener threaded stud  19 . Fastener threaded stud  19  is sized to slidably fit through protractor slot  17 . 
     Protractor indicia  27  is inscribed along the length of protractor  15  to aid in setting blade angle  30 . Protractor  15  is attached to first blade assembly arm  11  in a position such that protractor angle  26  read from protractor indicia  27  equals blade angle  30 . Protractor angle  26 , as read on protractor indicia  27 , may be defined by the location of fastener  18  along the length of protractor  15 , by reference to index line  28  on second blade assembly arm  21 , or any other appropriate reference. 
     In use, fastener threaded stud  19  is inserted through protractor slot  17  and threaded loosely into second blade assembly arm threaded bore  23 . Blade angle  30  is set as desired by rotating first blade assembly arm  11  relative to second blade assembly arm  21  as indicated by arrow  58  in  FIG. 3 . When the desired blade angle  30  is achieved, fastener  18  is tightened into second blade assembly arm threaded bore  23 , thus entrapping protractor  15  between fastener  18  and second blade assembly arm  21 , thus immobilizing protractor  15  relative to second blade assembly arm  21  and fixing blade angle  30 . Protractor indicia  27  corresponds to blade angle  30 , and may be used as explained above to aid in the determination of blade angle  30 . 
     While  FIGS. 3 and 4  depict protractor  15  attached to first blade assembly arm  11  and a threaded bore in second blade assembly arm  21 , it is intended to fall within the scope of this disclosure that protractor  15  could as easily be attached to second blade assembly arm  21  and that the threaded bore be disposed in first blade assembly arm  11 . 
       FIG. 5  is a right side isometric view of an alternate embodiment dual bladed surgical saw  2  with shims  32  being used to set blade angle  30 . In this embodiment, shims  32  are inserted between first blade assembly arm  11  and second blade assembly arm  21  as appropriate to achieve the blade angle  30  desired. The use of shims  32  is especially useful where a pre-determined blade angle  30 , such as sixty degrees, is desired, and can be achieved quickly and easily by insertion of the appropriately sized shim(s)  32 . 
       FIG. 6  is a right quarter side isometric view of an alternate embodiment dual bladed surgical saw  2  with one blade assembly removed, in this case second blade assembly  20 . A single blade assembly remains (in this case first blade assembly  10  having first blade  14 ) for use in conventional, single bladed surgical saw fashion. 
       FIGS. 7-9  depict the method of use for a dual bladed surgical saw  2  during an Austin bunionectomy on foot  40 . Blade angle  30  is set appropriate to the procedure, dual bladed surgical saw  2  is started, then the cuts are made by first blade  14  and second blade  24  at cut angle  45 , which is equal to blade angle  30 . In the example illustrated in  FIGS. 7-9 , cuts  44  are made in the head of metatarsal  42 . The bone is then fixed in place using appropriate fixation devices (K-wire  46  in  FIG. 9 ), and the procedure concluded in conventional manner. 
     Thus, the instant method of use for a dual bladed surgical saw includes the steps of: 
     A. Providing a dual bladed surgical saw comprising a saw body; a first blade assembly attached to the saw body; and a second blade assembly attached to the saw body; the first blade assembly comprising a first oscillator driving a first blade, and saw teeth at and end of the first blade opposite the first oscillator; the second blade assembly comprising a second oscillator driving a second blade, and saw teeth at and end of the second blade opposite the second oscillator; the first blade being disposed at a pre-determined blade angle relative to the second blade;
 
B. Starting the saw whereby the first oscillator causes the first blade to reciprocate, and the second oscillator causes the second blade to reciprocate; and
 
C. Using the first blade and the second blade to simultaneously make two cuts at the blade angle relative to each other.
 
     The instant method of use for a dual bladed surgical saw may include the further steps of pre-setting the blade angle at substantially sixty degrees; and using the dual bladed surgical saw to make two cuts in a first metatarsal bone at substantially sixty degrees relative to each other. 
     The instant method of use for a dual bladed surgical saw may include the further steps of providing means of rotating the first blade assembly relative to the second blade assembly; setting a blade angle between the first blade and the second blade; and making cuts at a cut angle relative to each other which equals the pre-set blade angle. 
     The instant method of use for a dual bladed surgical saw may include the further steps of providing a blade assembly arm attached to each of the blade assemblies, providing a protractor attached to one of the blade assembly arms and a threaded bore in the other blade assembly arm; providing a protractor slot in the protractor; providing a fastener having a threaded stud sized to slidably fit through the protractor slot and mate with the threaded bore; sliding the threaded stud through the protractor slot and threading the threaded stud loosely into the threaded bore, rotating one blade assembly relative to the other blade assembly until a desired blade angle is achieved; and tightening the threaded stud into the threaded bore, thereby releasably fixing the blade angle. 
     The instant method of use for a dual bladed surgical saw may include the further steps of providing protractor indicia on the protractor; and using the protractor indicia to aid in setting the desired blade angle. 
     The instant method of use for a dual bladed surgical saw may include the further steps of providing a blade assembly arm attached to each of the blade assemblies; providing at least one shim; rotating one blade assembly relative to the other blade assembly until a desired blade angle is achieved; and emplacing the at least one shim between the blade assembly arms, thereby releasably fixing the blade angle. 
     The instant method of use for a dual bladed surgical saw may include the further steps of providing a blade assembly which is removable from the dual bladed surgical saw; removing the removable blade assembly from the dual bladed surgical saw; and operating the dual bladed surgical saw in conventional fashion as a single bladed surgical saw. 
     In the preferred embodiment, saw body  4 , first oscillator  12 , first blade  14 , second oscillator  22 , and second blade  24  were commercially available items. Protractor  15 , first blade assembly arm  11  and second blade assembly arm  21  were made of metal, stainless steel, synthetic, plastic, or other appropriate material. Fastener  18  was a commercially available fastener. 
     While a preferred embodiment of the invention has been illustrated herein, it is to be understood that changes and variations may be made by those skilled in the art without departing from the spirit of the appending claims. 
     DRAWING ITEM INDEX 
     
         
           2  dual bladed surgical saw 
           4  saw body 
           6  battery 
           8  switch 
           10  first blade assembly 
           11  first blade assembly arm 
           12  first oscillator 
           14  first blade 
           15  protractor 
           16  teeth 
           17  protractor slot 
           18  fastener 
           19  fastener threaded stud 
           20  second blade assembly 
           21  second blade assembly arm 
           22  second oscillator 
           23  second arm assembly threaded bore 
           24  second blade 
           26  protractor angle 
           27  protractor indicia 
           28  index line 
           30  blade angle 
           32  shim 
           40  foot 
           42  first metatarsal 
           44  cut 
           45  cut angle 
           46  K-wire 
           50  arrow 
           52  arrow 
           54  arrow 
           56  arrow 
           58  arrow