Abstract:
A vitreous body cutter for cutting a vitreous body in an eye includes: an inner cylindrical blade having a first suction hole and a suction path; an outer cylindrical blade having a second suction hole, the outer cylindrical blade holding the inner cylindrical blade to be rotatable about a center axis thereof; a main body fixed with the outer cylindrical blade; a diaphragm arranged in the main body, the diaphragm being linearly advanced to a distal end side of the blades in a direction of the center axis by supplying compressed gas into a gas chamber formed by the diaphragm and the main body; and a converting-and-transmitting mechanism which converts linearly advancement of the diaphragm into a rotation about the center axis and transmits the rotation to the inner cylindrical blade to rotate the inner cylindrical blade about the center axis.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a vitreous body cutter for cutting a vitreous body in an eye and a vitreous body surgical equipment (apparatus) having the same  
         [0002]     In a vitreous body cutter used in vitreous body surgery, a vitreous body in an eye is drawn by suction (aspiration) through a suction (aspiration) hole formed in the vicinity of an extremity (a distal end) of an outer cylindrical (tubular) blade fixed to a cutter main body, to thus cause the vitreous body to fit into the suction hole. An inner cylindrical (tubular) blade is caused to linearly reciprocate in a direction of the center axis thereof with respect to the outer cylindrical blade (a guillotine type) (refer to U.S. Pat. No. 6,383,203 (JP-A-2001-87303)) or rotationally reciprocate about the center axis (a rotary type) (refer to U.S. Pat. No. 5,176,628 (JP-A-H03-207355)), to thus excise the fitted vitreous body.  
         [0003]     Meanwhile, in the case of the guillotine type, the suction hole cannot be provided at the extremity of the outer cylindrical blade in view of a structure of the cutoff type and therefore, the vitreous body proximate to a retina is difficult to be cut (excited). In contrast thereto, in the case of the rotary type, the suction hole can be provided at the extremity of the outer cylindrical blade and therefore, the vitreous body proximate to the retina is easy to be cut (excited).  
         [0004]     Two types of rotary structures are known; one is a structure in which the inner cylindrical blade is rotated in one direction by a motor included in the cutter main body, and the other is a structure in which the inner cylindrical blade is rotationally reciprocated by reciprocating a piston in a cylinder (chamber) included in the cutter main body by controlling and supplying compressed gas (refer to U.S. Pat. No. 5,176,628 (JP-A-3-207355)). However, the former is difficult to handle since the weight becomes heavy. Further, the vitreous body is easy to be involved between the outer cylindrical blade and the inner cylindrical blade by the one-directional rotation. On the other hand, the latter needs to overcome conflicting problems of reducing friction resistance between the piston and the cylinder and ensuring airtightness therebetween, conversion efficiency of converting pressure energy of the compressed gas into rotational energy is not excellent and a stable function is difficult to be ensured by a small drive source.  
       SUMMARY OF THE INVENTION  
       [0005]     In view of the problem of the related art, an object of the invention is to provide a vitreous body cutter of a rotary type capable of cutting a vitreous body stably even by a small drive source and a vitreous body surgical equipment (apparatus) having the same.  
         [0006]     In order to resolve the above-described problem, the invention is characterized in providing the following constitution.  
         [0007]     (1) A vitreous body cutter for cutting a vitreous body in an eye, the vitreous body cutter comprising:  
         [0008]     an inner cylindrical blade having a first suction hole and a suction path;  
         [0009]     an outer cylindrical blade having a second suction hole, the outer cylindrical blade holding the inner cylindrical blade to be rotatable about a center axis thereof;  
         [0010]     a main body fixed with the outer cylindrical blade;  
         [0011]     a diaphragm arranged in the main body, the diaphragm being linearly advanced to a distal end side of the blades in a direction of the center axis by supplying compressed gas into a gas chamber formed by the diaphragm and the main body; and  
         [0012]     a converting-and-transmitting mechanism which converts linearly advancement of the diaphragm into a rotation about the center axis and transmits the rotation to the inner cylindrical blade to rotate the inner cylindrical blade about the center axis.  
         [0013]     (2) The vitreous body cutter according to (1), wherein  
         [0014]     the converting-and-transmitting mechanism includes a lead screw, a nut and a torsion spring, the lead screw and the nut being brought in mesh with each other,  
         [0015]     one of the lead screw and the nut is fixed to the inner cylindrical blade,  
         [0016]     the other of the lead screw and the nut is linearly advanced by the diaphragm being linearly advanced against spring force of the torsion spring by supplying the compressed gas into the gas chamber to rotate the one in a first direction, and  
         [0017]     the other is linearly retreated by the diaphragm being linearly retreated by the spring force of the torsion spring by releasing the gas from the gas chamber to rotate the one in a second direction opposed to the first direction.  
         [0018]     (3) The vitreous body cutter according to (1), wherein  
         [0019]     the converting-and-transmitting mechanism includes a lead screw and a nut, the lead screw and the nut being brought in mesh with each other,  
         [0020]     one of the lead screw and the nut is fixed to the inner cylindrical blade,  
         [0021]     the other of the lead screw and the nut is linearly advanced by the diaphragm being linearly advanced by supplying the compressed gas into the gas chamber to rotate the one in a first direction, and  
         [0022]     the other is linearly retreated by the diaphragm being linearly retreated by sucking the gas from the gas chamber to rotate the one in a second direction opposed to the first direction.  
         [0023]     (4) The vitreous body cutter according to (1), wherein  
         [0024]     the main body includes a blade portion fixed with the outer cylindrical blade holding the inner cylindrical blade, and a drive mechanism portion provided with the diaphragm and the converting-and-transmitting mechanism, and  
         [0025]     the blade portion and the drive mechanism portion are separable from each other.  
         [0026]     (5) The vitreous body cutter according to (4), further comprising a transmitting mechanism provided at the blade portion, the transmitting mechanism transmitting the rotation converted by the converting-and-transmitting mechanism to the inner cylindrical blade.  
         [0027]     (6) A vitreous body surgical equipment comprising:  
         [0028]     a vitreous body cutter according to claim  1 ;  
         [0029]     a gas supply unit which supplies the compressed gas into the gas chamber of the vitreous body cutter;  
         [0030]     a control unit which controls to supply the compressed gas; and  
         [0000]     a suction unit which generates suction pressure in the suction path in the inner cylindrical blade. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]      FIGS. 1A and 1B  are schematic side sectional views showing a state of fitting an inner cylindrical blade into an outer cylindrical blade.  
         [0032]      FIGS. 2A and 2B  are schematic front sectional views showing the state of fitting the inner cylindrical blade into the outer cylindrical blade.  
         [0033]      FIG. 3  is a schematic constitution view of a vitreous body cutter and a vitreous body surgical equipment having the same.  
         [0034]      FIG. 4  is a schematic constitution view showing a modified example of the vitreous body cutter. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0035]     An embodiment of the invention will be explained in reference to the drawings.  FIG. 3  is a schematic constitution view of a vitreous body cutter and a vitreous body surgical equipment having the same.  FIGS. 1A and 1B  are schematic side sectional views showing a state of fitting an inner cylindrical (tubular) blade into an outer cylindrical (tubular) blade.  FIGS. 2A and 2B  are schematic front sectional views showing the state of fitting the inner cylindrical blade into the outer cylindrical blade.  
         [0036]     A vitreous body cutter  20  cuts (excises) a vitreous body V by rotating an inner cylindrical blade  10  with respect to an outer cylindrical blade  1  between a state where an opening  3  of the outer cylindrical blade  1  and an opening  12  of the inner cylindrical blade  10  overlap each other (an open state where the opening  12  can be viewed from the opening  3 ) (refer to  FIG. 1A  and  FIG. 2A ) and a state where the opening  3  and the opening  12  do not overlap each other (a closed state in which the opening  12  cannot be viewed from the opening  3 ) (refer to  FIG. 1B  and  FIG. 2B ). When the opening  3  and the opening  12  overlap each other, the vitreous body V is drawn into a suction path (aspiration passage)  13  in the inner cylindrical blade  10 .  
         [0037]     The outer cylindrical blade  1  is formed into a hollow cylindrical shape having an outer diameter of about 0.7 mm to about 1.5 mm and a thickness of about 0.05 mm to 0.2 mm (an inner diameter of about 0.6 mm to about 1.1 mm). Further, a distal end thereof is formed with a curved (rounded) surface  2 . The reason for this is that consideration is taken for infliction of damage on a retina, which would otherwise be caused when the distal end of the outer cylindrical blade  1  comes into contact with the retina. As a matter of course, it may be a case that the curved surface is not formed.  
         [0038]     An opening  3  is formed at the distal end of the outer cylindrical blade  1  by cutting a portion of the curved surface  2 . This opening  3  is a suction (aspiration) hole for drawing the vitreous body V into the outer cylindrical blade  1  by suction (aspiration), and an edge  3  on an inner-wall-side of the opening  3  acts as an outer blade. The shape of the inner wall of the outer cylindrical blade  1  essentially coincides with the shape of an outer wall of an inner cylindrical blade  10  to be described later.  
         [0039]     The inner cylindrical blade  10  is fitted into the outer cylindrical blade  1  and is held so as to be rotatable about a center axis thereof. The inner cylindrical blade  10  is formed into a hollow cylindrical shape having an outer diameter essentially coincides with the inner diameter of the outer cylindrical blade  1  (a clearance of micrometers to tens of micrometers exists between the inner wall of the outer cylindrical blade  1  and the outer wall of the inner cylindrical blade  10 ). A curved (round) surface  11  substantially coinciding with the inner wall of the curved surface  2  of the distal end of the outer cylindrical blade  1  is formed at a distal end of the inner cylindrical blade  10 .  
         [0040]     An opening  12  is formed at the distal end of the inner cylindrical blade  10  by cutting a portion of the curved surface  11 . This opening  12  is a suction (aspiration) hole for drawing the vitreous body V into the inner cylindrical blade  10  by suction (aspiration), and an edge  12   a  on the outer wall-side of the opening  12  acts as an inner blade.  
         [0041]     When the opening  3  and the opening  12  overlap each other by rotating the inner cylindrical blade  10  within the outer cylindrical blade  1 , the vitreous body V is drawn into the suction path  13  in the inner cylindrical path  10  by suction. When the opening  12  and the opening  3  do not overlap each other by further rotating the inner cylindrical blade  10  within the outer cylindrical blade  1 , the vitreous body V is cut by meshing engagement between the edge  3   a  and the edge  12   a.    
         [0042]     The outer cylindrical blade  1  is fixed to a cover  21  of a cutter main body  20   a.  A lead screw  10   a  is fixed to a substantial middle portion (which is disposed in the main body  20   a ) of the inner cylindrical blade  10  fitted into the outer cylindrical blade  1 . The lead screw  10   a  is brought in mesh with a nut  22 , the nut  22  is fixed to a moving base  24 , and the moving base  24  is fixed to a diaphragm  23  arranged in the mainbody  20   a.  A material of the lead screw  10   a  is, for example, stainless steel. A material of the nut  22  is, for example, resin (polyimide) having poor affinity with the lead screw  10   a.  Friction resistance in converting linear reciprocating movement into rotational reciprocating movement is made to be reduced by combining the lead screw and the nut having different properties of surfaces thereof.  
         [0043]     An outer peripheral portion of the diaphragm  23  is pinched between and held by a cover  25  and a cover  26  of the main body  20   a.  The moving base  24  is fixed to the nut  22  through a hole  25   b  opened at a partition  25   a  of the cover  25 . The cover  26  is formed with nipples  26   a  and  26   c,  an opening  26   b  of the nipple  26   a  is communicated with a gas chamber  31  formed by the diaphragm  23  and an inner wall of the cover  26 , and an opening  26   d  of the nipple  26   c  is communicated with the suction path  13  in the inner cylindrical blade  10 . An outer peripheral portion of a substantial rear end portion of the inner cylindrical blade  10  is sealed from the diaphragm  23  and the cover  26  by O rings  30  to maintain airtightness of the suction path  13  and the gas chamber  31 .  
         [0044]     When compressed gas (compressed air) is supplied to the gas chamber  31  via the nipple  26   a,  the diaphragm  23  is linearly advanced (linearly moved forward) to a distal end side of the cutter  20  (the outer cylindrical blade  1  and the inner cylindrical blade  10 ) and the nut  22  fixed to the moving base  24  is linearly advanced in accordance therewith. By advancement of the nut  22 , the lead screw  10   a  and the inner cylindrical blade  10  fixed thereto are rotated about the center axis.  
         [0045]     Further, a compression spring  27  is provided between the lead screw  10   a  and the partition  25   a,  and the lead screw  10   a  and the inner cylindrical blade  10  are urged to the distal end side by spring force of the spring  27 . Further, a helical torsion spring  28  fixed to the cover  21  is fixed o the lead screw  10   a.  The spring  28  is provided with urge force for rotating the lead screw  10   a  in a direction reverse to the direction of rotating the lead screw  10   a  by the advancement of the nut  22 . An outer peripheral portion of the nut  22  is fixed with blocks  29  at two locations thereof for preventing the nut  22  from rotating, and the blocks  29  are slid in grooves  21   a  in the cover  21 . Holes  21   b  and  21   c  are holes for passing gas in accordance with movement of the nut  22 .  
         [0046]     Further, a relationship between the nut and the lead screw for converting the linear reciprocating movement into the rotational reciprocating movement may be reversed. That is, the lead screw may linearly be reciprocated and the nut fixed to the inner cylindrical blade  10  may rotationally be reciprocated.  
         [0047]     The nipple  26   a  communicated with the gas chamber  31  is communicated with an electromagnetic valve  105  of an operating unit  100  of the surgical equipment via a tube  42 , and the electromagnetic valve  105  is communicated with a compressing pump  106  for delivering the compressed gas. Further, the nipple  26   c  communicated with the suction path  13  is communicated with a suction pump  102  of the operating unit  100  via a tube  41 , and the pump  102  is communicated with an abandon chamber  101 . The electromagnetic valve  105 , the pump  106  and the pump  102  are controlled to be driven by a control portion  110  of the operating unit  100 . Further, the control portion  110  is connected with a setting panel  107  for setting surgical conditions, and a foot switch  108  for inputting signals for operating the electromagnetic valve  105 , the pump  106  and the pump  102 .  
         [0048]     Operation of the vitreous body surgical equipment having such a configuration will now be described. First, with the switches of the setting panel  107 , surgical conditions (e.g., suction pressure, a cutting speed of the cutter  20 , and the like) is set. Next, a perfusion (irrigation) liquid from an unillustrated perfusion liquid bottle is introduced into an eye of a patient. Moreover, the outer cylindrical blade  1  is inserted into the eye such that the opening  3  is situated a diseased area, such as an opaque are. Subsequently, the foot switch  108  is stepped on, to thus activate the pump  106  and electromagnetic valve  105  at a preset cutting speed and activate the pump  102  at preset suction (aspiration) pressure.  
         [0049]     When the electromagnetic valve  105  is opened, the compressed gas is supplied from the pump  106  to the gas chamber  31  via the tube  42  and the nipple  26   a.  Thereby, inner pressure of the gas chamber  31  is increased, the diaphragm  23  is linearly advanced against the spring force of the spring  28 , and the nut  22  is pressed to the distal end side via the moving base  24 . Since the nut  22  is prevented from rotating by the blocks  29 , the nut  22  is linearly advanced to the distal end side while rotating the lead screw  10   a.  The inner cylindrical blade  10  is rotated (regular rotation) by the rotation of the lead screw  10   a.    
         [0050]     When the electromagnetic valve  105  is closed, the gas chamber  31  is opened (communicated with the atmosphere) and the gas in the gas chamber  31  is delivered out. Thereby, the inner pressure of the gas chamber  31  is reduced, the lead screw  10   a  and the inner cylindrical blade  10  are rotated in a direction reverse to the previous direction by the spring force of the spring  28 , and the nut  22  is pressed back and linearly retreated (linearly moved backward) in the direction reverse to the previous direction. The moving base  24  and the diaphragm  23  is pressed back and linearly retreated by the treat of the nut  22 . The inner cylindrical blade  10  is rotationally reciprocated by controlling the opening/closing of the electromagnetic valve  105  by the control portion  110 .  
         [0051]     Further, instead of reversely rotating the inner cylindrical blade  10  by the spring force of the spring  28 , the inner cylindrical blade  10  may be reversely rotated by sucking the gas in the gas chamber  31  by providing a suction pump at a portion of the electromagnetic valve  105  communicated with the atmosphere. Further, the cutting speed can further be accelerated by utilizing both of the spring force of the spring  28  and negative pressure of the suction pump.  
         [0052]     The rotational reciprocation of the inner cylindrical blade  10  is for preventing involvement of the vitreous body V. When the inner cylindrical body  10  rotates about the center axis and the opening  3  and the opening  12  overlap each other, the vitreous body V is drawn into the suction path  13  by suction through the opening  3  and the opening  12 . When the inner cylindrical blade  10  rotates further, and the opening  3  and the opening  12  do not overlap each other, the vitreous body B is cut by meshing engagement between the edge  3   a  and the edge  12   a.  The cut vitreous body V is sucked by the suction force by the pump  102  and is discharged to the abandon chamber  101  via the tube  41 . By rotationally reciprocating the inner cylindrical blade  10 , a time period of overlapping the opening  3  and the opening  12  can be set to be longer than that in the case of the one-directional rotation and efficiency of drawing the vitreous body V by suction can be increased.  
         [0053]     Further, the inner cylindrical blade  10  of the cutter  20  is rotationally reciprocated by a single drive source (a source of making compressed gas flow in and out) and therefore, the inner cylindrical blade can be used with exchanging it for a vitreous body cutter of a guillotine type for linearly reciprocating the inner cylindrical blade. Further, by branching the tube  42  connected to the electromagnetic valve  105  by a three way plug and connecting the branched tube  42  to the vitreous body cutter of the guillotine type, both of the rotary type vitreous body cutter  20  and the guillotine type vitreous body cutter can be used. For example, the vitreous body at a center portion in the eye is cut by the vitreous body cutter of the guillotine type having excellent cutting efficiency and the vitreous body at a vicinity of the retina is cut by the vitreous body cutter  20  of the rotary type and so on.  
         [0054]      FIG. 4  is a schematic constitution view showing a rotary type vitreous body cutter according to another embodiment. Although the vitreous body cutter is basically disposable, the vitreous body cutter of  FIG. 4  is constructed by a construction in which by making a blade side and a drive mechanism side of the vitreous body cutter separable, only the blade side is disposable and the drive mechanism side is reused. In  FIG. 4 , members the same as those of the above-described embodiment are attached with the same notations and detailed explanation thereof will be omitted.  
         [0055]     A vitreous body cutter  80  is constituted by a drive mechanism portion  80   a  and a blade portion  80   b  separable therefrom. The outer cylindrical blade  1  is fixed to a cover  61  of the blade portion  80   b,  and the inner cylindrical blade  10  is held to be rotatable about the center axis by O rings  30  fixed to the cover  61  and the outer cylindrical blade  1 . A side surface of the inner cylindrical blade  10  is formed with a hole  10   b  and a flange  10   c.  A compression coil spring  67  is provided ay the cover  61  by a lid  62  screwed to the cover  61 , and the inner cylindrical blade  10  is urged to the distal end side via the flange  10   c  by spring force of the spring  67 . Further, a rear end portion of the inner cylindrical blade  10  is formed with a projected portion  10   d.    
         [0056]     The cover  61  and a cover  65  can be coupled by a screw  68 . A cover  64  is fixed to the cover  65  and a cover  66  is fixed to the cover  64 . A shaft  60  having a lead screw  60   a  is axially supported by a partition  64   a  of the cover  64 . The lead screw  10   a  is brought in mesh with the nut  22 , the nut  22  is fixed to the moving base  24 , and the moving base  24  is fixed to a diaphragm  63 . An outer peripheral portion of the diaphragm  63  is pinched between and held by the cover  64  and the cover  66 . The moving base  24  is fixed to the nut  22  via a hole  64   b  opened at the partition  64   a  of the cover  64 . The helical torsion spring  28  fixed to the cover  65  is fixed to the lead screw  60   a.  The spring  28  is provided with urge force of rotating the lead screw  60   a  in a direction reverse to a direction of rotating the lead screw  60   a  by advancement of forward the nut  22 . The outer peripheral portion of the nut  22  is fixed with the blocks  29  for preventing rotation of the nut  22  at the two locations and the blocks  29  are slid in grooves  65   a  in the cover  65 . Holes  65   c  and  65   d  are holes for passing gas in accordance with movement of the nut  22 . A distal end of the shaft  60  is fixed with a fitting portion  69  and the fitting portion  69  is fitted with the projected portion  10   d  of the inner cylindrical blade  10  to transmit rotation of the shaft  60  to the inner cylindrical blade  10 . That is, the fitting portion  69  and the projected portion  10   d  constitute a transmitting mechanism for transmitting rotational reciprocating movement of the shaft  60 .  
         [0057]     The cover  66  is formed with nipples  66   a  and  66   c.  An opening  66   b  of the nipple  66   a  is communicated with a gas chamber  71  formed by the diaphragm  63  and an inner wall of the cover  66 . An opening  66   d  of the nipple  66   c  is communicated with the suction path  13  in the inner cylinder portion  10  via a suction path  64   c  in the cover  64 , a suction path  65   b  in the cover  65 , a suction path  61   a  at inside of the cover  61 , and the hole  10   b  of the inner cylindrical blade  10 . O rings  72  are fitted between the suction path  65   b  of the cover  65  and the suction path  61   a  of the cover  61  in order to maintain airtightness.  
         [0058]     The nipple  66   a  communicated with the gas chamber  71  is communicated with the electromagnetic valve  105  via the tube  42 . The nipple  66   c  communicated with the suction path  13  is communicated with the pump  102  via the tube  41 .  
         [0059]     When compressed gas is supplied to the gas chamber  71 , inner pressure of the gas chamber  71  is increased, the diaphragm  63  is linearly advanced against the spring force of the spring  28 , and the nut  22  is pressed to the distal end side via the moving base  24 . Since the nut  22  is prevented from rotating by the blocks  29 , the nut  22  is linearly advanced to the distal end side while rotating the lead screw  60   a.  The inner cylindrical blade  10  is rotated (regularly rotated) by the rotation of the lead screw  60 .  
         [0060]     The gas chamber  71  is opened (communicated with the atmosphere), the gas in the gas chamber  71  is delivered out, the inner pressure of the gas chamber  71  is reduced, the lead screw  60   a  is rotated in a direction reverse to a previous direction by the spring force of the spring  28 , the nut  22  is pressed back and linearly retreated in the direction reverse to the distal end side. The moving base  24  and the diaphragm  63  are pressed back and linearly retreated by retreat of the nut  22 . Further, by reversely rotating the lead screw  60   a,  also the inner cylindrical blade  10  is rotated reversely.  
         [0061]     According to the vitreous body cutter  80 , by loosening the screw  68 , the blade portion  80   b  can be separated from the drive mechanism portion  80   a  and only the blade portion  80   b  can be interchanged.