Abstract:
A surgical cast cutter for removing orthopedic bandages of a hard casting material type: includes a cutting tool comprising first shank, cutting portion, and second shank; a first housing having a built-in rotating means which rotates said cutting tool; a tool holding means which rotatably holds said cutting tool; a second housing which receives said cutting tool and having an integrated horseshoe-shaped protrusion which is inserted between the hard cover and affected area as a guide such that said hard cover may be easily cut; and a hood which is coupled to said second housing and movable in the up and down direction.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a surgical instrument and particular to a cast cutter for removing orthopedic bandages of a hard casting material type, and a method for casting the affected area such that the cast may be easily cut by using the cast cutter.  
           [0003]    [0003] 2 . Description of the Related Art  
           [0004]    Various devices and methods to remove a cast from an affected area of a patient have been developed. For example, an electric saw having a rotating or oscillating blade has been used to remove the cast from the affected area of a patient.  
           [0005]    This electric saw has been proved to be unsatisfactory for many reasons. In particular, this electric saw often shocks the patient who is getting the cast removed due to the near approach of the rotating or oscillating blade against the affected area and the noise and debris generated when said electric saw piercingly cuts the cast. These disadvantages occur especially when the patient is a child.  
           [0006]    In addition, because of the above disadvantages, cast cuttings using the electric saw remove the cast from the affected area by carefully penetrating through the cast such that the rotating or oscillating blade does not contact the affected area and cutting the cast once and then by using a separate mechanical device for spreading the cut cast open.  
           [0007]    The reason for this is because of the possibility of shock to the patient and that the operator must perform the task of cutting the cast with the electric saw, which requires extreme caution, twice on two uniform portions of the cast to avoid using a separate mechanical device to spread the cut cast open, and this asserts agony for both the patient and the operator.  
         SUMMARY OF THE INVENTION  
         [0008]    Therefore, the object of the present invention is to provide a cast cutter which does not apply shock or injury to the patient when removing the cast from the affected area, and which is provided with a hood which can be moved up and down according to the flexion caused from the difference in thickness of the cast and at the same time collect dust and debris formed when removing the cast.  
           [0009]    Another object of the present invention is to provide a casting method through which the cast cutter according to this invention may perform the cutting operations easily when removing a cast from an affected area.  
           [0010]    To achieve the above mentioned objects, the cast cutter according to this invention includes a cutting tool comprising a first shank, cutting portion, and second shank; a first housing having a built-in rotating means which rotates said cutting tool; a tool holding means which rotatably holds said cutting tool; a second housing which receives said cutting tool and having an integrated horseshoe-shaped protrusion which is inserted between the hard cover and affected area as a guide such that said hard cover may be easily cut; and a hood which is coupled to said second housing and movable in the up and down direction.  
           [0011]    The method of cutting the cast by using the cast cutter configured as the above comprises the steps of wrapping a cast padding on the affected area; adhering adhesive tape of a smooth surfaced strip shape on said cast padding under the hard cover portion to be cut when the hard cover is removed from the affected area with the hard cover cutter; and wrapping the hard cover on said cast padding on which said adhesive tape is adhered on a portion thereof. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The preferred embodiments of this invention will now be described with reference to the attached figures wherein  
         [0013]    [0013]FIG. 1 is a perspective view of the main portion of the cast cutter according to this invention;  
         [0014]    [0014]FIG. 2 is a cross-sectional view of a cast cutter provided with a dust collector hood;  
         [0015]    [0015]FIG. 3 is a perspective view of an affected area wrapped with cast padding;  
         [0016]    [0016]FIG. 4 is a perspective view of adhesive tape adhered on to a portion of the cast padding of FIG. 3;  
         [0017]    [0017]FIG. 5 is a perspective view of a hard cover wrapped on the cast padding of FIG. 4 onto which adhesive tape is adhered; and  
         [0018]    [0018]FIG. 6 is a perspective view of the cast cutter of this invention applied to the cast formed as FIG. 5. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    A cast cutter having a first housing ( 1 ) extended longitudinally and having an opening ( 12 ) on the bottom of the front end thereof, and a cutting tool ( 2 ) mounted on the bottom of the front end of said first housing ( 1 ) perpendicular to the direction of the longitudinal axis of said first housing ( 1 ) is depicted in FIGS. 1 and 2.  
         [0020]    A stop plate ( 1   a ) which closes opening ( 12 ) formed on the bottom of the front end of the first housing ( 1 ) holds the mounted cutting tool ( 2 ) such that it may be rotationally driven by motor ( 3 ).  
         [0021]    The front axle ( 4 ) of said motor ( 3 ) extends to the front end side of the housing ( 1 ), and a transmission ( 5 ) is connected thereto to convey the dynamic power of said motor ( 3 ) to a set of bevel gears ( 10 ) in predetermined revolutions. Said transmission ( 5 ) is connected to a set of bevel gears ( 10 ) to convert the rotation centered on a first output axle ( 5   a ) parallel to the front axle ( 4 ) to a rotation centered on a second output axle ( 11 ) perpendicular to said first output axle ( 5   a ).  
         [0022]    As depicted in FIG. 2, the bevel gear ( 10 ) of the output side which the second output axle ( 11 ) is passed through integrally has on the output side a cylindrical portion ( 20 ) with a H-shape cross-section coupled to said second output axle ( 11 ) in a key connection. Therefore, said cylindrical portion ( 20 ) rotates in same revolutions as said second output axle ( 11 ).  
         [0023]    Said cylindrical portion ( 20 ) has a interposing first bearing ( 21 ) rotatably mounted on the stop plate ( 1   a ) which closes said opening ( 12 ) formed on the bottom of the front end of said first housing ( 1 ), as shown in FIG. 2. Therefore, said third output axle ( 13 ) rotates in same revolutions as said cylindrical portion ( 20 ).  
         [0024]    Said cutting tool ( 2 ) is comprised of a first shank ( 2   a ), a cutting portion ( 2   b ), and a second shank ( 2   c ), as shown in FIG. 1, and the proximal end portion of said first shank ( 2   a ) is coupled to said third output axle ( 13 ) in the key connection manner. Therefore, said cutting tool ( 2 ) rotates in same revolutions as said third output axle ( 13 ).  
         [0025]    As depicted in FIG. 1, the first shank ( 2   a ) of said cutting tool ( 2 ) has a stopper ( 2   a ′) formed on the center thereof, the cutting portion ( 2   b ) of said cutting tool ( 2 ) has cutting blades (for example, two or three cutting blades) formed in spiral shape, and the second shank ( 2   c ) of said cutting tool ( 2 ) has a diameter smaller than that of said cutting portion ( 2   b ).  
         [0026]    The first shank ( 2   a ), excluding the proximal end portion of said cutting tool ( 2 ), respectively has second bearings ( 22 , 22 ) interposed on the circumference of the top and bottom portions where it contacts said stopper ( 2   a ′) and the second housing ( 15 ) is rotatably inserted and mounted.  
         [0027]    The distal end of said second housing ( 15 ) has a horseshoe shaped protrusion ( 16 ) formed thereon which serves as a cutting guide for said cutting tool ( 2 ), said horseshoe shaped protrusion ( 16 ) is comprised of a first portion ( 16   a ) extended parallel to said cutting tool, and a second portion ( 16   b ) integrally connected to the distal end of said first portion ( 16   a ) extending from the distal end of said first portion in the perpendicular direction of said cutting tool ( 2 ).  
         [0028]    On said second portion ( 16   b ) there is formed a second opening ( 17 ), and in the second opening ( 17 ) said second shank ( 2   c ) of said cutting tool ( 2 ) interposes a third bearing ( 23 ) and is inserted therein. In addition, said second portion ( 16   b ) has a plate shape, the thickness decreases from the distal end to the proximal end and from the center portion to both ends.  
         [0029]    Said second housing ( 15 ), which has threads formed on the upper portion of the outer surface, is joined together with the cascaded first joint ( 19 ) through which the first shank ( 2   a ) of the cutting tool ( 2 ) is passed through, as depicted in FIG. 2, said first joint ( 19 ) is coupled to said stop plate ( 1   a ) at the upper portion. In addition, said first joint ( 19 ) is inserted into a second joint ( 30 ) which has a cascaded shape corresponding to that of said first joint ( 19 ) in the inner surface thereof, said second joint ( 30 ) is coupled to the stop plate ( 1   a ) of said first housing ( 1 ) as shown in FIG. 2.  
         [0030]    Said second housing ( 15 ) has adhered on the outer surface thereof in a key connection a hood ( 50 ) connected to a duct channel ( 6 ) which suctions and guides debris generated during cast cutting through the rotation of a impeller mounted on a separate motor other than the motor ( 3 ) mounted on said cast cutter. Here, said duct channel ( 6 ) is connected to a collection chamber ( 9 ) installed separately from said cast cutter.  
         [0031]    Between said hood ( 50 ) and said second joint ( 30 ) there is interposed a spring ( 51 ), on a portion of the outer surface of said second housing ( 15 ) there is formed a long slot-type groove ( 52 ) in the longitudinal direction of said second housing ( 15 ), on a location of said hood ( 50 ) corresponding to the slot-type groove ( 52 ) there is formed a threaded aperture, and bolt ( 54 ) passes through said aperture and is inserted into said slot-type groove ( 52 ) coupling said hood ( 50 ) and said second housing ( 15 ).  
         [0032]    Therefore, through the above configuration, said hood ( 50 ) may be resiliently moved up and down along the slot-type groove ( 52 ) and thereby the cast cutter is not interfered by the curves of the cast caused from the varying thickness of the cast when advancing for the cast cutting operation.  
         [0033]    Said hood ( 50 ) may be formed of a light transparent material to display the state of the debris of the cast being suctioned into the collection chamber ( 9 ), and to be connected to said duct channel ( 6 ), there is formed on the proximal end of the cast cutting direction an angled nipple-type connector ( 50   a ), and on the distal end there is formed a display ( 50   b ) showing the cast cutting direction.  
         [0034]    In addition, the outer surface of said hood ( 50 ) is formed of a smooth surface to facilitate the cast cutting operations, and all edges are rounded.  
         [0035]    The operation of the cast cutter is now described.  
         [0036]    The motor ( 3 ) which is connected to a power source (not shown) drives the front axle ( 4 ), said front axle ( 4 ) rotates the first output axle ( 5   a ) in predetermined revolutions through the transmission ( 5 ). Then, one of the bevel gears, among the set of bevel gears ( 10 ), mounted on the first output axle ( 5   a ) in a key connection manner rotates in the revolutions of the first output axle ( 5   a ), the other bevel gear which is meshed in a ninety degree angle with said one of the bevel gears rotates with a output axle ( 11 ) disposed forming a ninety degree angle with said first output axle ( 5   a ).  
         [0037]    When said output axle ( 11 ) rotates, the cylindrical portion ( 20 ), which mounts said output axle ( 11 ) on one side in a key connection, rotates and accordingly the third output axle ( 13 ) which is connected in a key connection manner rotates.  
         [0038]    Then, the cutting tool ( 2 ) which is connected in key connection with said third output axle ( 13 ) is rotated. Here, the second portion ( 16   b ) of the second housing ( 15 ) is inserted between the normal cast padding wrapped around the affected area and the hard cover wrapping around the normal cast padding, and the cast cutter is advanced. Said hard cover is cut by the cutting tool ( 2 ) consequent to the advancement thereof.  
         [0039]    When said hard cover is cut by said cutting tool ( 2 ), the debris from the hard cover is collected in the collection chamber ( 9 ) through the hood ( 50 ) and duct channel ( 6 ).  
         [0040]    The preferred embodiments of the method of casting the affected area such that the cast may be easily cut by the cast cutter according to the present invention will be described hereinafter.  
         [0041]    The method according to this invention is a casting method which allows smooth movement of the horseshoe shaped protrusion of the second housing, which serves as a guide for the hard cover cutter, when in between the hard cover and the cast padding during the cast removal process.  
         [0042]    [0042]FIG. 3 depicts an affected area (arm) ( 100 ) of a patient wrapped in soft, light cast padding ( 120 ).  
         [0043]    As in the state depicted in FIG. 3, on said cast padding ( 120 ) smooth surfaced, light, strip shaped adhesive tape ( 130 ) is adhered, as shown in FIG. 4, on the portion where the horseshoe shaped protrusion ( 210 ), which serves as a cutting tool guide for the hard cover cutter ( 200 ), which will be described hereinafter is moved.  
         [0044]    As depicted in FIG. 5, said cast padding ( 120 ), on which said adhesive tape ( 130 ) is adhered onto the portion where the horseshoe shaped protrusion ( 210 ) of the hard cover cutter ( 200 ) is to be moved, is wrapped by the hard cover ( 140 ). Said hard cover may be, for example, plaster bandages, polyethylene resin and the like.  
         [0045]    [0045]FIG. 6 depicts the hard cover cutter ( 200 ) applied to the cast formed on the affected area through the method described above.  
         [0046]    As shown in FIG. 6, the horseshoe shaped protrusion ( 210 ) of said hard cover cutter ( 200 ) is positioned between the hard cover ( 140 ) and the adhesive tape ( 130 ). When said hard cover cutter ( 200 ) is pushed by the hands of the operator, said protrusion ( 210 ) easily slides on the smooth surface of said adhesive tape ( 130 ), and thereby the cutting tool ( 220 ) installed in said hard cover cutter ( 200 ) is moved and allows said hard cover ( 140 ) to be easily cut.  
         [0047]    The cast cutter according to the present invention prevents shock or injury to the patient when the cast is removed from the affected area and therefore, the operator of the cast cutter does not need to work slow or be over-focused and thereby the cast may be removed from the affected area in a short amount of time.  
         [0048]    In addition, the cast cutter of this invention is able to collect dust and debris generated when removing the cast from the affected area and therefore does not discomfort the patient.  
         [0049]    In addition, conventionally, the cut cast needed to be removed from the affected area by a separate device, but the cast cutter of this invention allows the cast removal to be done quickly and easily and therefore the cutting operation may be done twice along spaced portions and in turn does not require a separate device to spread the cut cast open.  
         [0050]    In addition, by applying a cast according to the method of this invention, the cast is applied such that the horseshoe shaped protrusion mounted on the hard cover cutter of this invention does not get caught in the cast padding during cast removal operations and thereby the hard cover may be cut quickly and the cast may be removed swiftly.