Abstract:
A valvulotome device having retractable cutting blades and guide fins which permits continual centralizing, self-alignment of the cutting blades within the lumen of the vein is disclosed. The valvulotome device comprises a bifurcated assembly having a cutter head and guide head joined by a conduit member permitting communication of a catheter wire running longitudinally through the device. The cutter head and guide head each define a chamber adapted to receive the catheter wire therein. First and second wedge members are operatively engaged to the catheter wire and disposed inside a respective chamber of the cutter head and guide head which permit the surgeon to remotely manipulate the degree to which the cutting blades and guide fins emerge from the cutter head and guide head, respectively, as well as allow rotation of the device about its axis thereby increasing the maneuverability of the device as it is pulled through the vein.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority from U.S. Provisional Patent Application Ser. No. 60/550,710, filed Mar. 5, 2004. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to a medical device for the treatment of vascular disorders, and more particularly to a valvulotome for excising venous valves when performing in-situ vascular procedures, such as arterial bypass surgery.  
       BACKGROUND OF THE INVENTION  
       [0003]     Occasionally, as part of the medical treatment for distressed arteries in a patient&#39;s lower extremities, a bypass of an artery through its neighboring vein is made. This enables the vein to be used in place of the artery as the source of, and conduit for, blood pumped from the heart to the lower extremities. Unlike arteries, however, veins have internal one-way valves spaced periodically within the lumen of the vein which function to ensure that the flow of blood is directed back to the heart and does not reverse itself. These valves are comprised of tissue flaps disposed on the luminal wall inside the vein. The valves open when leg muscles contract to force blood to flow out of the lower extremities. The valves close when blood attempts to flow backwards after the leg muscles relax, thereby preventing a reverse flow of blood back through the vein. When a vein is recruited for use in an arterial bypass, it is crucial that the valves in the vein be removed, because they will otherwise impede the arterial flow if left in place.  
         [0004]     There exist devices, called valvulotomes, for cutting and removing the venous valve from the luminal passageways of the vein. These devices are designed to be inserted into the vein and passed along the lumen over the section of the vein that is to participate in the arterial bypass. The valvulotome is provided with one or more blades which are disposed on the device in a position to cut the venous valve. It is, however, essential that the venous wall itself is not cut or damaged by the blade because that would jeopardize the effectiveness of the vein as a bypass vessel.  
         [0005]     Prior art valvulotomes have been equipped with certain safeguards to help prevent inadvertent damage to the luminal walls of the vein. In some devices, the blades are configured to be retractable so that the valvulotome, with the blades in the closed position, can be initially inserted in the vein through the desired region and then be withdrawn, with the blades in an open position, to cut the valves. However, even a retractable blade can cause damage to the vein wall upon withdrawal of the valvulotome if the head of the device bearing the blades is not disposed centrally and evenly within the lumen of the vein. For instance, if the head of the valvulotome is off center within the lumen, one side of the vein wall may be cut into too deeply, while the other side of the vein wall may not even be engaged, thus leaving the valve on that side still intact in the vein.  
         [0006]     Some valvulotome devices provide for a centering mechanism to ensure that the valvulotome blades are centrally disposed within the vein lumen during the excision. This centering mechanism may comprise an enlarged body portion spaced proximally to, and slightly apart, from the blades. This serves two primary purposes: 1) to provide an annular guide for centralizing the blades within the lumen of the vein, and 2) to spread the vein walls apart to a greater degree than the cutting radius of the blades to limit the reach of the blades to the valves and prevent the blades from contacting the vein walls themselves. However, for veins having changing diameters along the area of treatment, a centering mechanism having a fixed dimension may be counterproductive in the cutting operation. If the centering mechanism is substantially less than the diameter of the vein lumen, it will not effectively center the valvulotome. If the centering mechanism is substantially greater than the diameter of the vein lumen, it may draw the valve flaps out of cutting range of the blades.  
         [0007]     Valvulotome devices are generally introduced into and through the vein by the use of catheters. While catheters are of extremely slender diameter and are quite flexible, a turn or bend in the vein, or branching of the vein, may place a kink in the catheter. If the valvulotome head is rigidly connected to the catheter, it may affect the ability of the blades to be centrally disposed within the vein lumen, thereby potentially causing an adverse effect on the excision procedure.  
         [0008]     Therefore, there is a need in the art for a valvulotome device having adjustable cutting blades and an adjustable guide mechanism which permits continual centralizing, self-alignment of the cutting blades within the lumen of the vein.  
       SUMMARY OF THE INVENTION  
       [0009]     A primary object of the present invention is to provide a valvulotome device that permits continual, self-alignment of the cutting blades within the lumen of a vein.  
         [0010]     Another object of the present invention is to provide a valvulotome device having adjustable cutting blades.  
         [0011]     A further object of the present invention is to provide a valvulotome device having a bifurcated assembly comprising a distal body including a cutter head and a proximal body including a guide head that may be manipulated simultaneously by the user.  
         [0012]     Another further object of the present invention is to provide a valvulotome device that permits remote manipulation and navigation of the device by a user through the vein of a patient.  
         [0013]     Yet a further object of the present invention is to provide a valvulotome device having a guide mechanism that permits continual centralizing, self-alignment of the cutting blades of the device within the lumen of a vein.  
         [0014]     In one embodiment, the present invention comprises a valvulotome device comprising a handle, a bifurcated assembly operatively engaged to handle having a distal portion including a cutter head, said cutter head having a plurality of retractable, radially oriented cutting blades and a proximal portion having a guide head, said guide head having a plurality of retractable, radially oriented guide fins, a catheter wire operatively engaged to cutter head and guide head through the handle and disposed within the bifurcated assembly, wherein said catheter wire permits remote manipulation of the cutter head and the guide head, operatively engaged to the catheter wire, first and second wedge members disposed inside the cutter head and guide head, respectively and in operative engagement with the plurality of cutter blades and plurality of guide fins, respectively, such that movement of each respective first and second wedge member controls the effective cutting diameter of the plurality of cutting blades and the effective diameter of the guide fins, respectively.  
         [0015]     In another embodiment, the present invention comprises a method of use comprising: a) providing a valvulotome device comprising a handle, a bifurcated assembly operatively engaged to handle having a distal portion including a cutter head, said cutter head having a plurality of retractable, radially oriented cutting blades and a proximal portion having a guide head, said guide head having a plurality of retractable, radially oriented guide fins, a catheter wire operatively engaged to cutter head and guide head through the handle and disposed within the bifurcated assembly, wherein said catheter wire permits remote manipulation of the cutter head and the guide head, operatively engaged to the catheter wire, first and second wedge members disposed inside the cutter head and guide head, respectively and in operative engagement with the plurality of cutter blades and plurality of guide fins, respectively, such that movement of each respective first and second wedge member controls the effective cutting diameter of the plurality of cutting blades and the effective diameter of the guide fins, respectively; b) inserting the bifurcated body into the vein; and c) pulling the bifurcated body back through the vein such that the valves of the vein are cut.  
         [0016]     In yet another embodiment, the present invention comprises a bifurcated assembly for use in a valvulotome device comprising a conduit member joined between a distal portion having a cutter head defining a chamber and a proximal portion having a guide head defining a chamber the head including a plurality of retractable radially oriented cutting blades, and the guide head including a plurality of retractable, radially oriented guide fins, wherein each of the cutter head and the guide head includes a wedge member disposed in each respective chamber and being adapted to operatively engage a catheter wire such that the diameters of cutting blades and guide fins can be adjusted by manipulation of the catheter wire.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is an illustration of the valvulotome device showing the handle operatively engaged to the bifurcated assembly according to the present invention.  
         [0018]      FIG. 2  is a front view of the bifurcated assembly with the blades and fins in the fully retracted position according to the present invention;  
         [0019]      FIG. 2A  is a front view of the bifurcated assembly with the blades and fins in the fully expanded position according to the present invention;  
         [0020]      FIG. 3  is an exploded view of the bifurcated assembly according to the present invention;  
         [0021]      FIGS. 4A-4C  illustrate the retractable and expanding operation of the cutter head and guide head for the bifurcated assembly according to the present invention;  
         [0022]      FIG. 5  is a perspective view of a cutting blade for the cutter head according to the present invention;  
         [0023]      FIG. 5A  is an enlarged view of the cutting blade according to the present invention;  
         [0024]      FIG. 6  is a partial cross-sectional view of the guide head showing the swivel member and wedge member according to the present invention;  
         [0025]      FIG. 7  is a side view of the handle according to the present invention;  
         [0026]      FIG. 8  is a cross-sectional view of the handle taken along line  8 - 8  of  FIG. 7  according to the present invention;  
         [0027]      FIG. 9  is a cross-sectional view of the handle taken along line  9 - 9  of  FIG. 7  according to the present invention;  
         [0028]      FIG. 10  is a cross-sectional view of the handle taken along line  10 - 10  of  FIG. 7  according to the present invention;  
         [0029]      FIG. 11  is an exploded view of the handle according to the present invention;  
         [0030]      FIG. 12  is a cross-sectional view showing the handle in the closed position according to the present invention;  
         [0031]      FIG. 12A  is an enlarged view of  FIG. 12  according to the present invention;  
         [0032]      FIG. 13  is a cross-sectional view showing the handle in the open position according to the present invention;  
         [0033]      FIG. 13A  is an enlarged view of  FIG. 13  according to the present invention;  
         [0034]      FIG. 14  is an orthogonal view of the wedge member according to the present invention;  
         [0035]      FIG. 15  is an end view taken along line  15 - 15  of  FIG. 2  with the cutting blades in their fully retracted position according to the present invention;  
         [0036]      FIG. 15A  is an end view taken along line  15 A- 15 A of  FIG. 2A  with the cutting blades in their fully expanded position according to the present invention;  
         [0037]      FIG. 16  is a cross-sectional view taken along line  16 - 16  of  FIG. 2  with the guide fins in their fully retracted position according to the present invention; and  
         [0038]      FIG. 16A  is a cross-sectional view taken along line  16 A- 16 A of  FIG. 2A  with the guide fins in their fully expanded position according to the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0039]     Referring to the drawings, a preferred embodiment of the valvulotome device according to the present invention is illustrated and generally indicated as  10  in  FIGS. 1-16 . The valvulotome device  10  comprises bifurcated assembly  12  operatively associated with a handle  14  through a catheter wire  16  encased inside the lumen of a flexible catheter  17 . The bifurcated assembly  12  provides a means for cutting valves in a vein of a patient as well as a guide means for maintaining the cutting means in a continual centralizing, self-alignment within the lumen of the vein when operated by the handle  14 .  
         [0040]     Referring to  FIGS. 2, 2A  and  3 , the bifurcated assembly  12  comprises a hollow conduit member  18  joined between a distal portion  20  having a cutter head  24  including a plurality of retractable, radially oriented cutting blades  28  and proximal portion  22  having a guide head  26  including a plurality of retractable, radially oriented guide fins  30 . The distal portion  20  defines a first chamber  50  in communication with a plurality of slots  84  ( FIG. 4A ) defined around the cutter head  24  adapted to permit each cutting blade  28  to extend radially outward, while the proximal portion defines a second chamber  52  that communicates with the first chamber  50  through a passageway  54  defined by conduit member  18 . Similarly, second chamber  52  communicates with a plurality of slots  86  ( FIG. 4A ) which permit the guide fins  30  to extend radially outward from the guide head  26 . The catheter wire  16  is received within the bifurcated assembly  12  at the proximal portion  22  through the first chamber  50  and passageway  54 , before terminating inside second chamber  52 . In addition, the catheter  17  is operatively associated with a swivel component  23  disposed inside the second chamber  52 .  
         [0041]     Referring to  FIG. 5 , each cutting blade  28  comprises a blade body  82  extendable through the slot  84  defined by cutter head  24  and a blade end  80  disposed inside the first chamber  50 . The blade end  80  is pivotally attached to a rearward part of the cutter head  24  and defines a channel portion  88 , while the blade body  82  terminates in a formed free end  90 . As further shown in  FIG. 5A , the blade body  82  defines a long flat bottom edge  96 , ending in a formed free end  90  where there is a sharp edge  98  that is adapted for cutting valves of a vein.  
         [0042]     Referring back to  FIG. 3 , the guide head  26  preferably includes a set of four guide fins  30  radially disposed equidistantly around the proximal portion  22  with each guide fin  30  having a guide body  94  extending through slot  86  and disposed inside second chamber  50 . The guide end  92  is pivotally attached to a rearward part of proximal portion  20 . Similar to the cutting blade  28 , each end  92  defines a channel portion  89 , while the guide body  94  terminates in a formed free end  91 .  
         [0043]     The catheter wire  16  defines a distal terminal end  100  operatively engaged with a first wedge member  32  moveably disposed inside the proximal portion  20 . Referring to  FIG. 14 , the first wedge member  32  comprises a wedge body  40  and a stem  72  with wedge member  32  being movable within the first chamber  50  and adapted to engage the long flat bottom edge  96  of the blade body  82  when the catheter wire  16  is manipulated by handle  14  as shall be discussed in greater detail below. Preferably, the wedge body  40  includes a set of opposing four-sided depression portions  66  and has the general appearance of a Maltese cross, although other suitable configurations that fall within the scope of the present invention are contemplated.  
         [0044]     The manipulation of the catheter wire  16  by handle  14  causes the first wedge member  32  to move which engages the long flat bottom edge  96  of each cutting blade  28  with each respective peak  67  of first wedge member  32 . Since the first wedge member  32  has a slightly greater diameter than the long flat bottom edge  96  of each cutting blade  28  this structural arrangement permits the wedge member  32  to gradually push each cutting blade  28  outwardly through slot  84  as illustrated in the sequence of  FIGS. 4A, 4B  and  4 C.  
         [0045]     In  FIG. 4A , the cutting blades  28  are fully retracted inside first chamber  50 , while in  FIG. 4B  the moving engagement of the first wedge member  32  against each cutting blade  28  causes the blades  28  to extend through each slot  84 . As such, the incremental advancement of the first wedge member  32  in relation to each cutting blade  28  effectively changes the degree to which the blade  28  emerges above the surface of the cutter head  24  from first chamber  50  into a cutting position as the first wedge member  28  moves along the long flat bottom edge  96  of each blade  28  as shown in  FIG.4C . In operation, each cutting blade  28  acts as a spring so that once the force from the first wedge member  32  is removed each cutting blade  28  returns to the originally fully retracted position inside the first chamber  50  ( FIG. 4A ). By this structural arrangement, the effective cutting diameter of the cutting blades  28  can be adjusted by the handle  14  through manipulation of the catheter wire  16  in a forward and backward movement with respect to bifurcated assembly  12 . As illustrated in  FIGS. 15 and 15 A, the effective cutting diameter of the cutting blades  28  in the fully retracted position and the fully expanded position are shown. Preferably, the cutter head  24  includes a set of opposing four-sided depression portions  66  and has the general appearance of a Maltese cross, although other suitable configurations that fall within the scope of the present invention are contemplated.  FIGS. 16 and 16 A illustrate the effective diameter of the guide fins  30  in the fully retracted position and the fully expanded position. Preferably, the guide head  26  includes a set of opposing four-sided depression portions  66  and has the general appearance of a Maltese cross, although other suitable configurations that fall within the scope of the present invention are contemplated.  
         [0046]     Similarly, second wedge member  34  is operatively engaged to catheter wire  16  and slidably disposed within second chamber  52  of guide head  26 . When the catheter wire  16  is manipulated, the second wedge member  34  is movable in a forward and backward movement inside second chamber  52  and engageable with the inner edge of each guide fin  30 . Since the second wedge member  34  has a slightly greater diameter than the inner edge of each guide fin  30  this structural arrangement permits the second wedge member  34  to push the guide fins  30  outwardly through slot  86  as the second wedge member  34  advances along the inner edge of each guide fin  30 . The incremental advancement of the second wedge member  34  in relation to the guide body  94  effectively changes the degree to which each guide fin  30  emerges above the surface of the guide head  26  from the second chamber  52 . Similar to the operation of the cutter head  24 , the guide fins  30  collectively act as a spring so that once the force from the second wedge member  34  is removed by manipulation of the catheter wire  16 , the guide fins  30  return to their originally retracted position inside second chamber  52  ( FIG. 4A ). As such, manipulation of the catheter wire  16  controls the effective diameter of the guide fins  30  as well as function to maintain the bifurcated assembly  12  in a centralized position inside the lumen of the vein during operation of the valvulotome device  10 .  
         [0047]     Because the first and second wedge members  32  and  34  are centrally disposed within the first and second chambers  50 ,  52 , respectively, the cutting blades  28  and guide fins  30  emerge equidistantly therefrom to ensure the centralized passage through the lumen of the vein of the bifurcated assembly  12  as well as uniform cutting of the venous valves by the cutter body  24 , while avoiding damage to the venous luminal walls. As such, the simultaneous adjustability of the cutting blades  28  and guide fins  30  permits the user to adjust the valvulotome device  10  “on-the-fly” when a vein of varying inner diameter is presented during the cutting procedure.  
         [0048]     Preferably, the effective diameter of the cutting blades  28  in the fully retracted position is 2.0 mm, while in the fully expanded position the effective cutting diameter is 4.0 mm. This calibration system provides the user of the valvulotome device  10  with the capability to adjust the effective cutting diameter of the cutting blades  28  to a midrange value of 3.0 mm by manipulation of the catheter wire  16 . Accordingly, the valvulotome device  10  provides the ability to adjust the effective cutting diameter of the cutter head  24  to 2.0 mm, 3.0 mm and 4.0 mm by the user.  
         [0049]      FIG. 7  illustrates the means for enabling the user to control the effective cutting diameter of the cutter head  24 . As noted above, manipulation of the catheter wire  16  directly affects simultaneous movement of the first and second wedge members  32 ,  34 , which in turn respectively engage the cutting blades  28  and guide fins  30 . Because of this direct relational movement between these various structural components, the valvulotome device  10  can be directly calibrated such that a desired incremental distance of remote movement of the first and second wedge members  32 ,  34  within the bifurcated assembly  12  can be accurately achieved by the user by effecting the identical, incremental distance movement of the catheter wire  16  at handle  14 . In addition, the bifurcated assembly  12  is free to swivel about its axis within the lumen of the vein, as seen in  FIG. 6 . The catheter  17  has attached to its distal end a swivel component  23 . The swivel component  23  consists of a profile change of the catheter  17  to create a flange. The swivel component  23 , which is permanently fixed the distal end of the catheter  17 , is housed inside the guide head  22 . The swivel component  23  remains fixed while the bifurcated assembly  12  can rotate about its axis. The bifurcated assembly  12  is fixed from motion in the longitudinal direction. The catheter wire  16  is free to pass through the swivel component  23  unobstructed and does not rotate.  
         [0050]     Referring to  FIGS. 7-11 , the handle  14  is adapted for use by a single hand of the user for manipulating the catheter wire  16  and adjusting the cutting blades  28  and guide fins  30 . The handle  14  comprises a handle body  36  having right housing  56  and left housing  58  that encases a retainer rack  44  and defines an opening  74  having a dial  46  rotatably disposed therethrough. As shown, the dial  46  defines a gripping surface  64  along the periphery thereof adapted for movement by a user&#39;s thumb and a pinion  78  adapted for operative engagement to the retainer rack  44  for manipulation of the catheter wire  16 . In addition, the dial  46  includes a plurality of visual indicia, such as indicator dots, for providing the user a visual verification of the diameter setting related to the effective cutting diameter of the cutting blades  28 . Retainer rack  44  includes a first rack  60  and second rack  62  which are operatively engaged to the proximal end  76  of catheter wire  16 . As further shown, catheter  17  is engaged through a relief strain  48  for defining the front portion of handle  14 .  
         [0051]     To ensure that the cutting blades  28  remain at the desired effective cutting diameter, the handle  14  further includes a locking mechanism  38  having locking notches  102 . Legs  104  of the first and second racks  60 ,  62  are adapted to engage corresponding locking notches  102  to lock the catheter wire  16  in a locked position.  
         [0052]     Referring to  FIG. 12 , the handle  14  is shown in the closed position for locking the catheter wire  16  in place. In the closed position, the pinion  78  is engaged to one portion of retainer rack  44  ( FIG. 12A ). In the closed position shown in  FIG. 13 , the pinion  78  is engaged to another portion of retainer rack  44  ( FIG. 13A ).  
         [0053]     It should be understood from the foregoing that, while particular embodiments of the invention have been illustrated and described, various modifications can be made thereto without departing from the spirit and scope of the invention as will be apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as defined in the claims appended hereto.