Patent Publication Number: US-2001000531-A1

Title: Electrocauterizing tool for orthopedic shave devices

Description:
RELATIONSHIP TO COPENDING APPLICATION  
     1. This application is a Utility Application which claims priority to Provisional Application No. 60/059,383, entitled Electrocauterizing Sheath for Arthroscopic Shave Device filed on Sep. 19, 1997. This application is related to Utility Application No. 09/034,830, entitled Clip on Electrocauterizing Sheath for Orthopedic Shave Devices filed on Mar. 4, 1998; and Utility Application No. 09/034,885, entitled Electrocauterizing TIP for Orthopedic Shave Devices filed on Mar. 4, 1998, all of which are incorporated herein by reference.  
    
    
     
       BACKGROUND OF THE INVENTION  
       2. 1. Field of the Invention  
       3. This invention relates to improved surgical and cauterizing apparatus and methods for their use.  
       4. 2. Description of Related Art  
       5. Arthroscopic surgery is becoming increasingly popular, because it generally does less damage than open procedures, produces less scarring in and around joints, and results in faster healing and return of the patient to full productivity.  
       6. Nevertheless, arthroscopic surgery has its limitations. The surgeon must operate through a narrow tube formed in the body on which surgery is being carried out, which is awkward. Only one probe can be used at a time for many operations. Often the viewing camera is positioned at an angle different from the surgeon&#39;s normal gaze. This contrasts with “open surgery” where the surgeon has relative ease of viewing the surgical site and can freely move both hands.  
       7. Occasionally, during the performance of an arthroscopic or similar minimally invasive procedure, a surgeon will penetrate a vessel within the surgical site. At this point, the surgeon may desire to cauterize the vessel.  
       8. One way of cauterizing the vessel is the use of radio frequency (RF) energy, as described in U.S. Pat. No. 5,100,402 to Fan. Such RF methods offer a quick and relatively easy way of cauterizing penetrated vessels. However, use of current RF cauterizing devices usually requires the surgeon to withdraw the surgical tool being used at the time, and insert a tool for cauterizing the penetrated vessel. This switching of the tools is usually required because of the space limitations involved in arthroscopic surgery.  
       9. This switching of tools during surgery can be time consuming, awkward, and potentially dangerous to the patient. Additionally, there is the danger of not being able to locate the penetrated vessel. Therefore, there is the need for an improved surgical apparatus and cutting and cauterizing device and methods for using the apparatus and device to avoid the above-mentioned problems.  
       SUMMARY OF THE INVENTION  
       10. In one aspect, the invention relates to a surgical apparatus, comprising a surgical instrument including a housing and a cannula, and the cannula attached at a proximal end to the housing and defining at a distal end thereof an opening and the housing containing a drive interface; and a surgical tool including a shaft and a tip, and the tip located in the opening, and the shaft contained within the cannula and the shaft mechanically and electrically coupled at a distal end to the tip, and at a proximal end, to the drive interface and an electrical interface, and the drive interface producing a surgical motion of the tip, and the electrical interface producing a cauterizing action of the tip.  
       11. In another aspect, the invention relates to a cutting and cauterizing device for connection to a surgical instrument, and the surgical instrument including a drive interface and a first interconnector, and the cutting and cauterizing device comprising a cannula defining at a distal end thereof an opening; a second interconnector, suitable for switchably coupling to a power supply, and the second interconnector located at the proximal end of the cannula and shaped to couple to the first interconnector; and a surgical tool including a shaft and a tip, and the tip located in the opening, and the shaft contained within the canula, and the shaft coupled at a distal end to the tip and at a proximal end mechanically coupled to the drive interface to permit a surgical motion of the tip, and electrically coupled to the second interconnector to permit a cauterizing action of the tip.  
       12. In yet another aspect, the invention relates to methods of performing surgical procedures, using the surgical apparatus or the cutting and cauterizing device in the course of performing the surgical procedure.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     13.FIG. 1A is an isometric view of an embodiment of the claimed surgical instrument.  
     14.FIG. 1B is an isometric view of another embodiment of the claimed surgical instrument, showing a retrofitted housing.  
     15.FIG. 2A is a cross section of the embodiment shown in FIG. 1B, having a generally conducting shaft.  
     16.FIG. 2B is a cross section of the embodiment shown in FIG. 1B, having a generally insulating shaft.  
     17.FIGS. 3A-D are cross-sectional views of other embodiments of the surgical instrument, showing details of different interconnector arrangements.  
     18.FIGS. 4A-B are cross-sectional views of embodiments of the surgical instrument, emphasizing different distal seal arrangements.  
     19.FIGS. 5A-B are cross-sectional views of embodiments of the surgical instrument, emphasizing different distal seal and tip arrangements.  
     20.FIGS. 6A-D are end-on views of tips, according to the invention, emphasizing different embodiments of the conducting and non-conducting portions.  
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     21.FIG. 1A shows an isometric view of surgical apparatus  100 , including surgical tool  102  and surgical instrument  110 . Surgical instrument  110  includes housing  108 , power cord  106 , and interconnector  112 . Housing  108  also includes push switch  116 , electrical contact  118 , spring  120 , wire  122 , and drive interface  132 . Surgical tool  102  includes drive coupling  130 , commutator  134 , shaft  140 , and tip  142 . Surgical tool  102  additionally includes cannula  114 , and opening  138 .  
     22. Surgical instrument  110  includes housing  108 , attached at a distal end, via interconnector  112 , to a proximal end of cannula  114 . The distal end of cannula  114  defines an opening  138 . Shaft  140  is contained within cannula  114 . Tip  142  is at the distal end of shaft  140  and protrudes through opening  138  at distal end of cannula  114 . At the proximal end of shaft  140  are located commutator  134 , and drive coupling  130 . Located within housing  108  is drive interface  132 , located adjacent to drive coupling  130 . Power cord  106  enters housing  108  at a proximal end. Power cord  106  electrically couples to electrical contact  118  via wire  122 . Push switch  116  is located on housing  108 . The push switch is connected to electrical contact  118 . The electrical contact is aligned with commutator  134 . Spring  120  biases electrical contact  118  away from the commutator.  
     23. In operation, drive interface  132  engages drive coupling  130  to produce surgical motion of tip  142 , which is transmitted by shaft  140 . Push switch  116  may be depressed against spring  120  to create an electrical contact between electrical contact  118  and commutator  134 . This closes a circuit between the power supplied through power cord  106  and wire  122  through shaft  140  to tip  142 , thereby producing a cauterizing action at the tip  142 .  
     24. It should be noted that the surgical motion in any of the embodiments of this invention, can be, for example, rotary, reciprocal, rotary-reciprocal, etc. The shaft and cannula can be straight, or can include an arcuate section. In those instances where the surgical tool contains an arcuate section, the shaft may contain a flexible section to accommodate the motion of the shaft.  
     25.FIG. 1B shows another isometric view of a different embodiment of the invention, wherein the use of a removable interconnector allows the surgical tool to be removed from the housing. FIG. 1B shows surgical apparatus  100 , which includes surgical instrument  110 , and surgical tool  102 . Surgical instrument  110  includes housing  108 . Surgical tool  102  includes drive coupling  130 , interconnector  112 , shaft  140 , tip  142 , cannula  114 , and opening  138 . Interconnector  112  includes wire  122 . Housing  108  includes power cord  106 , and drive interface  132 .  
     26. Cannula  114  is connected at a proximal end to interconnector  112 . The interconnector may be removably connected to a distal end of housing  108 . Distal end of cannula  114  defines opening  138 . Shaft  140  is contained within the cannula and has at its distal end tip  142 , which protrudes through opening  138  in the cannula. The proximal end of the shaft extends into the housing. Drive coupling  130  is affixed to the proximal end of the shaft. The drive coupling and the proximal end of the shaft are contained within the housing. Power cord  106  is connected to a proximal end of the housing. Also within the housing is a drive interface  132 , positioned adjacent to the drive coupling. Wire  122  is removably attached to the exterior of the housing. The wire is used to connect a power supply to the interconnector.  
     27. In operation, drive interface  132  is energized by power cord  106 , and engages drive coupling  130  to produce a surgical motion of tip  142 , which is transmitted via shaft  140 . Electrical power is supplied via wire  122  to interconnector  112  to tip  142 , via shaft  140 , so as to produce a cauterizing action at tip  142 . The design of the interconnector allows the surgical tool to be removed from the housing.  
     28.FIGS. 2A-B are enlarged cross-sectional views of interconnector  112 . In FIGS. 2A-B, an embodiment of the invention is shown in which the interconnector is removable from housing  108  as shown in FIG. 1B. FIG. 2A shows such an embodiment, where shaft  140  is generally conducting, while FIG. 2B shows such an embodiment where the shaft is generally non-conducting, but has an interior conductor  240 .  
     29.FIG. 2A shows surgical apparatus  200 , which includes housing  108 , and interconnector  112 . The housing includes extended housing portion  208 . Interconnector  112  includes outer O-ring seal  206 , locking member  216 , interconnector conductor  250 , electrical connector  252 , and locking ring  218 . Also shown are cannula  114 , inner alignment piece  230 , and shaft  140 , drive coupling  130 , commutator  260 . Furthermore, drive interface  132  is shown.  
     30. Shaft  140  is contained within cannula  114 , and kept separate from the cannula by inner alignment piece  230 . The cannula, inner alignment piece, and shaft are connected at their proximal ends to housing  108  via interconnector  112 . Interconnector  112  serves to locate the shaft, inner alignment piece, and cannula. Interconnector  112  includes locking member  216  which is shaped so as to secure the cannula within extended housing portion  208 . The locking member also has a notch  212 , which is located opposite a detent  210  located on an interior surface of the extended housing portion. The locking member additionally includes outer o-ring seal  206 , located between the locking member exterior surface and the extended housing portion interior surface. The extended housing portion includes exterior threads  214 A, located so as to be opposite interior threads  214 B, which are located on locking ring  218 . Located at a proximal end of shaft  140  are commutator  260  and drive coupling  130 . Wire  122  delivers power to commutator  260  via interconnector conductor  250 , and electrical connector  252 . The electrical connector is located such that it is in electrical connector with commutator  260 .  
     31. In operation, interconnector  112  serves to attach inner alignment piece  230 , shaft  140  and cannula  114  to the housing. The inner alignment piece serves to locate the shaft within the cannula, and also serves as a bearing for the shaft. Locking member  216  serves to locate the inner alignment piece within extended housing portion  208  through the engagement of notch  212  on the locking member and detent  210  on the interior of the extended housing portion. Locking ring  218  serves to secure the locking member, together with the cannula, inner alignment piece and shaft, within the extended housing portion. The locking ring accomplishes this via the cooperative action of its interior threads  214 B and exterior threads  214 A, which are located on the exterior surface of the extended housing portion. Drive coupling  130  serves to impart a surgical motion to shaft  140 . Outer O-ring seal  206  serves to prevent transmission of body fluids that may be present at the distal end of the shaft through to the housing. Electrical power is provided via wire  122 , to commutator  260 . Commutator  260  is electrically coupled to distal end of shaft  140 , thus producing a cauterizing effect at the distal end of the shaft. FIG. 2B shows a cross section of another embodiment of surgical apparatus  200 , which shows a generally insulating shaft including an interior conductor  240 . The elements, their arrangement and function are identical to those described above in FIG. 2A with the following differences. The interior conductor is located within shaft  140 . The shaft is generally insulating. The interior conductor electrically couples commutator  280  to the distal end of the shaft, thereby permitting a cauterizing action at the distal end of the shaft.  
     32.FIGS. 3A-D are enlarged cross-sectional views of interconnector  112 . In FIGS. 3A-D, an embodiment of the invention is shown in which surgical tool  102  and the interconnector are removable from housing  108 . FIGS. 3A-B show cross-sectional views of the surgical apparatus shown in FIG  1 A. In the cross section views shown in FIG. 3A-B, the electrical interface is integrated into the housing, rather than being located within the interconnector. FIGS. 3A-B. show an electrical interface between the tool and power supply, located in the housing. FIGS. 3C-D are cross-sectional views of the apparatus shown in FIG  1 B, in which the electrical interface is integrated into the interconnector, rather than being located within the interconnector. FIGS. 3C-D show an electrical interface, between the surgical tool and power supply, located in the interconnector.  
     33.FIG. 3A shows surgical apparatus  300 , which includes housing  108 , interconnector  112 , and surgical tool  102 . Also shown is RF signal source  304 . The housing includes extended housing portion  208 , push switch  116 , spring  120 , and electrical contact  118 . Interconnector  112  includes outer O-ring seal  206 , locking member  216 , and locking ring  218 . Surgical tool  102  includes cannula  114 , inner alignment piece  230 , shaft  140 , drive coupling  130 , commutator  134 , inner O-ring seal  320 , and distal O-ring seal  332 .  
     34. Shaft  140  is contained within cannula  114 , and kept separate from the cannula by inner alignment piece  230 . Distal O-ring seal  332  is located within a retaining groove at a distal end of shaft  140 , and is in contact with the interior of the inner alignment piece. The cannula, inner alignment piece, and shaft are connected at their proximal ends to housing  108  via interconnector  112 . The inner alignment piece locates inner o-ring seal  320  between the inner alignment piece and the shaft near the proximal end of the inner alignment piece and the shaft. Interconnector  112  serves to locate the shaft, inner alignment piece, and cannula. Interconnector  112  includes locking member  216  which is shaped so as to secure the cannula within extended housing portion  208 . The locking member also has a notch  212 , which is located opposite a detent  210  located on an interior surface of the extended housing portion. The locking member additionally includes outer o-ring seal  206 , located between the locking member exterior surface and the extended housing portion interior surface. The extended housing portion includes exterior threads  214 A, located so as to be opposite interior threads  214 B, which are located on locking ring  218 . Located at a proximal end of shaft  140  are commutator  134  and drive coupling  130 . RF signal source  304  is electrically coupled via wire  122  which is coupled in turn with electrical contact  118 , via push switch  116 . The electrical contact is located such that it is in removable contact with commutator  134 . Push switch  116 , which is spring biased by spring  120 , is located on an exterior surface of the housing.  
     35. In operation, interconnector  112  serves to attach inner alignment piece  230 , shaft  140  and cannula  114  to the housing. The inner alignment piece serves to locate the shaft within the cannula, and also serves as a bearing for the shaft. Locking member  216  serves to locate the inner alignment piece within extended housing portion  208  through the engagement of notch  212  on the locking member and detent  210  on the interior of the extended housing portion. Locking ring  218  serves to secure the locking member, and thus the whole of surgical tool  102 , within the extended housing portion. The locking ring accomplishes this via the cooperative action of its interior threads  21   4 B and exterior threads  214 A, which are located on the exterior surface of the extended housing portion. Drive coupling  130  serves to impart a surgical motion to shaft  140 . Distal O-ring seal  332 , outer O-ring seal  206  and inner O-ring seal  320  serve to prevent transmission of body fluids that may be present at the distal end of the shaft through to the housing. RF signal source  304  serves to provide power via wire  122 , and electrical contact  118  to commutator  134 . Commutator  134  is electrically coupled to distal end of shaft  140 , thus producing a cauterizing effect at the distal end of the shaft. The electrical circuit is closed when push switch  116  is depressed against spring  120  to bring electrical contact  118  into electrical contact with commutator  134 . FIG. 3B shows a cross section of another embodiment of surgical apparatus  300 , which shows a generally insulating shaft including an interior conductor  240 . The elements, their arrangement and function are identical to those described above in FIG. 3A with the following differences. The interior conductor is located within shaft  140 , and electrically couples commutator  134  to the distal end of the shaft, thereby permitting a cauterizing action at the distal end of the shaft.  
     36.FIGS. 3C-D show an electrical interface, between the surgical tool and power supply, located in the interconnector. In particular, FIGS. 3C-D show embodiments of the invention that may include existing housings, thus allowing retrofitting of such housings in the practice of the invention. Such retrofitting is expressly and generally within the scope of the invention. FIG. 3C shows surgical apparatus  300 , which includes housing  108 , interconnector  112 , and surgical tool  102 . Also shown are foot switch  302 , and RF signal source  304 . The housing includes extended housing portion  208 . Interconnector  112  includes outer O-ring seal  206 , locking member  216 , interconnector conductor  250 , electrical connector  252 , and locking ring  218 . Surgical tool  102  includes cannula  114 , inner alignment piece  230 , shaft  140 , drive coupling  130 , commutator  260 , inner O-ring seal  320 , and distal O-ring seal  332 .  
     37. Shaft  140  is contained within cannula  114 , and kept separate from the cannula by inner alignment piece  230 . Distal O-ring seal  332  is located within a retaining groove at a distal end of shaft  140 , and is in contact with the interior of the inner alignment piece. The cannula, inner alignment piece, and shaft are connected at their proximal ends to housing  108  via interconnector  112 . The inner alignment piece locates inner o-ring seal  320  between the inner alignment piece and the shaft near the proximal end of the inner alignment piece and the shaft. Interconnector  112  serves to locate the shaft, inner alignment piece, and cannula. Interconnector  112  includes locking member  216  which is shaped so as to secure the cannula within extended housing portion  208 . The locking member also has a notch  212 , which is located opposite a detent  210  located on an interior surface of the extended housing portion. The locking member additionally includes outer o-ring seal  206 , located between the locking member exterior surface and the extended housing portion interior surface. The extended housing portion includes exterior threads  214 A, located so as to be opposite interior threads  214 B, which are located on locking ring  218 . Located at a proximal end of shaft  140  are commutator  134  and drive coupling  130 . RF signal source  304  is electrically coupled to commutator  260  via foot switch  302 , wire  122 , interconnector conductor  250 , and electrical connector  252 . Commutator  260  is electrically coupled to distal end of shaft  140 .  
     38. In operation, interconnector  112  serves to attach inner alignment piece  230 , shaft  140  and cannula  114  to the housing. The inner alignment piece serves to locate the shaft within the cannula, and also serves as a bearing for the shaft. Locking member  216  serves to locate the inner alignment piece within extended housing portion  208  through the engagement of notch  212  on the locking member and detent  210  on the interior of the extended housing portion. Locking ring  218  serves to secure the locking member, and thus the whole of surgical tool  102 , within the extended housing portion. The locking ring accomplishes this via the cooperative action of its interior threads  214 B and exterior threads  214 A, which are located on the exterior surface of the extended housing portion. Drive coupling  130  serves to transfer a surgical motion from a drive interface (not shown) to shaft  140 . Distal O-ring seal  332 , outer O-ring seal  206  and inner O-ring seal  320  serve to prevent transmission of body fluids that may be present at the distal end of the shaft through to the housing. RF signal source  304  serves to provide power to commutator  260  via foot switch  302 , wire  122 , interconnector conductor  250 , and electrical connector  252 . Commutator  260  is electrically coupled to distal end of shaft  140 , thus producing a cauterizing effect at the distal end of the shaft.  
     39.FIG. 3D shows a cross section of another embodiment of surgical apparatus  300 , which shows a generally insulating shaft including an interior conductor  240 . The elements, their arrangement and function are identical to those described above in FIG. 3A with the following differences. The interior conductor is located within generally insulating shaft  140 , and electrically couples commutator  280  to the distal end of the shaft, thereby permitting a cauterizing action at the distal end of the shaft.  
     40.FIG. 4A shows a cross section of the distal end of a surgical apparatus according to the invention, featuring details of tip  142 , including conducting and non-conducting portions, and a distal O-ring seal arrangement. Surgical apparatus  300  includes cannula  114 , inner alignment piece  230 , shaft  140 , tip  142 , distal O-ring seal  332 , distal O-ring seat  402 , and opening  138 .  
     41. Shaft  140  is contained within inner alignment piece  230  which in turn is contained within cannula  114 . Cannula  114 , at its distal end, defines opening  138 . The distal end of the shaft is attached to tip  142 , which is located within the opening. The distal end of the shaft also includes distal O-ring seats  402 . Distal O-ring seal  332  is located within the distal O-ring seat and is in contact with the interior surface of the inner alignment piece.  
     42. In operation surgical motion that is imparted to shaft  140  is thereby transmitted to tip  142 . In addition, electrical power delivered to shaft  140  produces a cauterizing effect at tip  142 . Inner alignment piece  230  serves to align shaft  140  within cannula  114 , and also serves as a bearing surface for shaft  140 . Together the shaft, inner alignment piece, and distal O-ring seat  402 , and distal O-ring seal  332  serve to produce a seal that prevents transmission of body fluids that may be present at opening  138  from being transmitted along the interface between the inner alignment piece and the shaft.  
     43.FIG. 4B shows a cross-section of the distal end of a surgical apparatus according to the invention, featuring details of tip  142 , including conducting and non-conducting portions, and a distal O-ring seal arrangement. Surgical apparatus  300  includes cannula  114 , inner alignment piece  230 , shaft  140 , tip  142 , distal O-ring seal  332 , distal O-ring seat  404 , and opening  138 .  
     44. Shaft  140  is contained within inner alignment piece  230  which in turn is contained within cannula  114 . Cannula  114 , at its distal end, defines opening  138 . The distal end of the shaft is attached to tip  142 , which is located within the opening. The distal end of the inner alignment piece also includes distal O-ring seat  404 . Distal O-ring seal  332  is located within the distal O-ring seat and is in contact with the interior surface of the inner alignment piece.  
     45. In operation surgical motion that is imparted to shaft  140  is thereby transmitted to tip  142 . In addition, electrical power delivered to shaft  140  produces a cauterizing effect at tip  142 . Inner alignment piece  230  serves to align shaft  140  within cannula  114 , and also serves as a bearing surface for shaft  140 . Together the shaft, inner alignment piece, and distal O-ring seat  404 , and distal O-ring seal  332  serve to produce a seal that prevents transmission of body fluids that may be present at opening  138  from being transmitted along the interface between the inner alignment piece and the shaft.  
     46.FIG. 5A shows a cross section of the distal end of a surgical apparatus according to the invention, featuring details of generally non-conducting tip  142 , and a distal O-ring seal arrangement. Included are cannula  114 , inner alignment piece  230 , shaft  140 , distal O-ring seal  332 , and distal O-ring seat  402 . Tip  142  includes interior conductor  240 , and conducting portion  504 .  
     47. Shaft  140  is contained within inner alignment piece  230  which in turn is contained within cannula  114 . The distal end of the shaft is attached to tip  142 . The distal end of the shaft also includes distal O-ring seat  402 . Distal O-ring seal  332  is located within the distal o-ring seat, and is in contact with the interior surface of the inner alignment piece. Interior conductor  240  runs through an interior portion of shaft  140  and the tip, and is electrically coupled to a plurality of conducting portions  504  at a single, distal, location. The plurality of conducting portions radiate arcuately along a longitudinal axis of the shaft, and are present at portions of the exterior surface of the tip.  
     48. In operation, surgical motion that is imparted to shaft  140  is thereby transmitted to tip  142 . In addition, electrical power delivered along interior conductor  240  is transmitted to conducting portion  504 , thus producing a cauterizing effect. Inner alignment piece  230  serves to align shaft  140  within cannula  114 , and also serves as a bearing surface for shaft  140 . Together shaft  140 , inner alignment piece  230 , distal O-ring seat  404 , and distal O-ring seal  332  serve to produce a seal that prevents transmission of body fluids that may be present at the distal end of the shaft from being transmitted along the interface between the inner alignment piece and the shaft.  
     49.FIG. 5B shows a cross section of the distal end of a surgical apparatus according to the invention, featuring details of another embodiment of a generally non-conducting tip  142 , and a distal O-ring seal arrangement. Included are cannula  114 , inner alignment piece  230 , shaft  140 , distal O-ring seal  332 , and distal O-ring seat  404 . Tip  142  includes interior conductor  240 , and conducting portions  550 .  
     50. Shaft  140  is contained within inner alignment piece  230  which in turn is contained within cannula  114 . The distal end of the shaft is attached to tip  142 . The distal end of the inner alignment piece also includes distal O-ring seat  404 . Distal O-ring seal  332  is located within the distal O-ring seat, and is in contact with the interior surface of the inner alignment piece. Interior conductor  240  runs through an interior portion of shaft  140  and the tip, and is electrically coupled to a plurality of conducting portions  550  at multiple locations within the tip and/or optionally within the distal portion of the shaft. The plurality of conducting portions radiate along a radius extending from a longitudinal axis of the shaft. The conducting portions are present at portions of the exterior surface of the tip.  
     51. In operation, surgical motion that is imparted to shaft  140  is thereby transmitted to the tip. In addition, electrical power delivered along interior conductor  240  is transmitted to conducting portions  550 , thus producing a cauterizing effect. Inner alignment piece  230  serves to align shaft  140  within cannula  114 , and also serves as a bearing surface for shaft  140 . Together shaft  140 , inner alignment piece  230 , distal O-ring seat  404 , and distal O-ring seal  332  serve to produce a seal that prevents transmission of body fluids that may be present at the distal end of the shaft from being transmitted along the interface between the inner alignment piece and the shaft.  
     52.FIG. 6A shows an end-on view of a tip shown in cross-sectional view in FIGS. 4A-B, and features various arrangements of the conducting and non-conducting portions. Tip  142  includes conducting portion  602 , non-conducting portions  604 , and cutting edges  606 .  
     53. Conducting portion  602  and non-conducting portions  604  are present on the surface of the tip, and have cutting edges  606  in between them.  
     54. In operation, tip  142  may be moved in a surgical motion. Additionally, electrical power may be supplied to conducting portions  602 , which then permit a cauterizing effect originating at cutting edges  606  to take place. Substantially less or no cauterizing effect takes place at or near non-conductive portions  604 .  
     55.FIG. 6B shows an end-on view of a tip shown in cross-sectional view in FIG. 5A, and features various arrangements of the conducting and non-conducting portions. Tip  142  includes conducting portion  626 , and non-conducting portions  628 . Conducting portion  626  and non-conducting portions  628  are present on the surface of tip  142 .  
     56. In operation, tip  142  may be moved in a surgical motion, with conducting portions  626  serving as cutting edges. Additionally, electrical power may be supplied to the conducting portions, which then permit a cauterizing effect to take place.  
     57.FIG. 6C shows an end-on view of a tip shown in cross-sectional view in FIG. 5B, and features various arrangements of the conducting and non-conducting portions. Tip  142  includes conducting portion  650 , non-conducting portions  652 , and cutting edges  654 .  
     58. Conducting portion  650  and non-conducting portions  652  are present on the surface of tip  142 . Cutting edges  654  are present on the surface of the tip, and in between the conducting and the non-conducting portions.  
     59. In operation, tip  142  may be moved in a surgical motion, utilizing cutting edges  654 . Additionally, electrical power may be supplied to conducting portions  650 , which then permit a cauterizing effect to take place. Substantially less or no cauterizing effect takes place at or near non-conductive portions  652 .  
     60.FIG. 6D shows an end-on view of another embodiment of a generally non-conducting tip, featuring various arrangements of the conducting and non-conducting portions. Tip  142  includes conducting portion  678 , non-conducting portions  676 , and cutting edges  680 .  
     61. Conducting portion  678  and non-conducting portions  676  are present on the surface of tip  142 . Cutting edges  680  are present on the surface of the tip, and in between the conducting and the non-conducting portions.  
     62. In operation, tip  142  may be moved in a surgical motion, utilizing cutting edges  680 . Additionally, electrical power may be supplied to conducting portions  678 , which then permit a cauterizing effect to take place. Substantially less or no cauterizing effect takes place at or near non-conductive portions  676 .  
     63. It will be apparent to those skilled in the art that various modifications and variations can be made in the apparatus and methods of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.