AU5585086A

AU5585086A - Electrosurgical device

Info

Publication number: AU5585086A
Application number: AU55850/86A
Authority: AU
Inventors: Alexander S. Borsanyi
Original assignee: American Hospital Supply Corp
Current assignee: Baxter International Inc
Priority date: 1985-03-14
Filing date: 1986-02-24
Publication date: 1986-10-13
Also published as: JPS62502175A; WO1986005379A1; EP0217828A1

Description

ELECTROSURGICAL DEVICE

BACKGROUND OF THE INVENTION

In some instances, the lateral muscles of the knee pull the patella laterally so that the patella is no longer centered on the knee joint. This condition can be treated with lateral release surgery by cutting the fibrous band known as the retinaculum to allow the patella to return to the center of the knee joint.

This surgery can be accomplished as an open procedure or arthoscopically. The arthoscopic surgery can be carried out with an electrosurgical device, and one such electrosurgical device has an electrode of about one millimeter in length for cutting the fibrous band. However, this prior art electrosurgical device is somewhat unsafe in that there is little or no protection against charring or burning, and the relatively short electrode does not have the desired length for all applications.

Cunningham Patent Application Serial No. filed on even date herewith and entitled MENISCAL CUTTING DEVICE discloses an electrosurgical device which is particularly adapted for cutting the meniscus to treat torn cartilage in the knee. This electrosurgical device employs a variable length electrode and various safety features to minimize the likelihood of burning or charring within the knee. The electrode is flexible and is supported at its opposite ends by electrode supports. Although the device shown in the Cunningham application could be used for lateral release surgery, a knife cut would first be necessary. SUMMARY OF THE INVENTION

This invention overcomes these disadvantages by providing an electrosurgical device which has the advantages of the Cunningham electrosurgical device described above, but which does not require any preliminary knife cuts in order to accomplish lateral release surgery. More specifically, this invention provides an electrosurgical device having a variable length electrode which terminates in a free distal end thereby eliminating the electrode supports of the Cunningham electrosurgical device. With this construction, no preliminary knife cut is necessary in order to carry out the lateral release surgery.

Because the electrode has a variable length, it may be made very short to facilitate insertion into the incision in the knee and thereafter extended for cutting. Preferrably, the variable length electrode has a minimum length of substantially zero. Electrode length can be remotely varied as desired during the surgery to accommodate the various different conditions within the knee.

Because the distal end of the electrode is unsupported, it is necessary that the electrode have sufficient rigidity to be self-supporting and to be self- supporting when used for cutting purposes. On the other hand, in order to have a variable length and extend in the desired direction, the electrode is preferably not completely rigid. In a preferred construction, the electrode is resiliently deformable. An electrosurgical device constructed in accordance with this invention preferably has an elongated probe having a distal end and a generally longitudinally extending passage opening at a port at the distal end of the probe. The probe is adapted for insertion through a cannula or an incision. An elongated member having proximal and distal end portions extends within the passage, and the distal end portion of the elongated member is extendible out of the port to form an electrode for electrosurgery. In order that the electrosurgical device can be used for lateral release surgery, the distal end portion of the elongated member is extendible out of the port in a first direction which is different from the direction of elongation of the probe. In a preferred construction, the first direction is generally transverse to the direction of elongation. For lateral release surgery, the first direction should form at least a 30 degree angle with the direction of elongation and preferably forms at least a 60 degree angle with the direction of elongation. The elongated member and the probe are relatively movable to move the elongated member longitudinally of the passage so that the electrode can project out of the port for a variable distance. The proximal end portion of the elongated member is releasably fixable against movement in the passage so that the length of the electrode can be releasably fixed. The electrode is coupled to a source of electrical energy so that the electrode can be used to cut or coagulate tissue.

Another feature of the invention is that at least a region of the distal end portion of the probe is curved. The curved region at least assists in directing the- electrode generally in the first direction. In addition, the curved region supports the elongated member against torsional loads and provides a visible indication to the surgeon of the direction in which the electrode will extend. To facilitate insertion of the probe, the maximum overall dimension of the distal end portion of the probe as viewed in side elevation is no more that about two millimeters.

An optional, but preferred, feature of the invention, which can be employed with or without the curved region of the probe is that at least a region of the distal end portion of the elongated member is curved in the unstressed condition. This curvature at least assists in causing the electrode to extend in the first direction. In addition, the curvature of the elongated member cooperates with the curvature of the distal end portion of the probe to facilitate longitudinal movement of the elongated member within the passage of the probe. For this purpose, the radii of the two curved regions are preferably approximately the same. The resilience of the elongated member enables the curved region of the elongated member to be at least partially resiliently straightened by the probe when the curved region is in the passage of the probe.

Although the elongated member can be of various different constructions, preferably it includes a proximal section and a distal section with the proximal and distal sections being joing together. For added column strength, the proximal section is preferably stiffer than the distal section.

The electrosurgical device also preferably includes a handpiece adapted to be manually grasped and means for releasably attaching the probe to the handpiece with at least a portion of the proximal end portion of the elongated member extending into the handpiece. The handpiece includes means for moving the elongated member to vary the length of the electrode.

To minimize the likelihood of unintentional burning or charring, the exposed regions of the probe which" could contact the patient are nonconductive and may be electrically insulated. If desired, water or other nonionic solution can be supplied through the probe to the electrode to wash away debris. The invention, together with additional features and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying illustrative drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an isometric view of an electrosurgical device constructed in accordance with the teachings of this invention with the button on the handpiece being shown in its retracted position and with the electrode being shown in dashed lines in the extended position.

Fig. 2 is an enlarged, fragmentary view partially in section taken generally along line 2-2 of Fig. 1 with the button on the handpiece being shown in its retracted position and with the electrode being shown in dashed lines in the extended position.

Fig. 2a is a fragmentary, side elevational view of the distal end portion of the elongated member in the unstressed condition.

Fig. 3 is an axial, fragmentary sectional view of the probe assembly with the electrode in the extended position. Fig. 4 is an enlarged, fragmentary sectional view taken generally along line 4-4 of Fig. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Figs. 1 and 2 show an electrosurgical cutting and coagulating device 11 which generally comprises a probe assembly 13 and a handpiece 15 coupled to an electrical power supply 17 and a water supply 19. Generally, a distal segment of the probe assembly 13 is insertable through an incision to perform electrosurgery, and the handpiece 15 includes the components necessary to provide control of the surgery. The power supply 17 may be of a type commonly used for electrosurgery, such as Model No. MF-180A which is obtainable from Aspen Laboratories of Englewood, Colorado.

The probe assembly 13 includes an elongated probe 21 which has an elongated, axial passage 23 extending longitudinally from a proximal end 25 (Fig. 3) of the probe and opening at a port 27 at a distal end 29. Although the probe 21 can be of various different constructions, in the embodiment illustrated, it comprises a main tube 31 (Fig. 3) , a tubular guide 33 received within a distal end portion of the main tube, a distal tube 35 received within the guide 33, solder 37 for retaining the tube 35 within the guide 33 and the guide 33 within the tube 31, and a bushing 39 retained on a proximal region of the main tube 31 by epoxy 41 and/or solder 43. The bushing 39 has an annular flange 42 at its proximal end for use in attachment of the probe assembly 13 to the handpiece 15. A short pin 44 projects proximally of the flange 42 for use in supplying electrical energy to the probe assembly 13. The tubes 31 and 35, the guide 33 and the bushing 39 are constructed of conductive metal. The entire outer surface of the probe 21 which is defined by the outer surface of the bushing 39 and portions of the outer surfaces of the main tube 31 and the distal tube 35 are covered with an insulating jacket 45 which is applied as by spraying.

In this embodiment, the main tube 31 is of larger diameter than the distal tube 35, the latter being smaller to facilitate insertion through an incision and into the confined space of the knee. Although various configurations can be used, in the illustrated embodiment, the tubes 31 and 35 are both cylindrical, and by way of example, the distal tube 35 may have an outer diameter of about .020 to .032 inch.

The distal tube 35 has a curved region 47 which forms at least part of the distal end portion of the probe 21. As shown in Fig. 3, the probe 21 is elongated along an axis 49, and the curved region 47 curves away from the axis 49 to extend generally transverse to the direction of elongation of the probe. Although various constructions are possible, in this embodiment, the curved region 47 extends all the way to the distal end 29, and the distal end 29 lies in a plane which is parallel to the axis 49. The illustrated embodiment of this invention is particularly adapted for use as a lateral release cutting device for the knee, and accordingly, the maximum overall dimension of the distal end portion of the probe 21 as viewed in side elevation, i.e., in Fig. 2, is no more than about two millimeters. In other words, the dimension "X" (Fig. 2) from the lower surface (as viewed in Fig. 2) of the distal tube 35 to the plane of the distal end 29 is no more than about two millimeters. The angle through which the curved region 47 turns can be varied depending upon the results desired. However, it is generally preferred to have the curved region 47 extend through at least about 60 degrees. Similarly, the radius of curvature can be varied depending upon the results desired, and in the embodiment illustrated, the radius of curvature to the inner side 50 (Fig. 3) of the curved region 47 is about .187 inch.

The probe assembly 13 also includes an elongated member 51. Although the elongated member 51 can be of various different constructions, in the embodiment- illustrated, it comprises a proximal section 53 and a distal section 55 partially received within a bore in the distal end portion of the proximal section. The sections 53 and 55 may be held together by solder. The proximal section 53, in the embodiment illustrated, is in the form of a relatively stiff conductive, metal rod which terminates at its proximal end in an enlarged head 57 (Fig. 2) .

The distal section 55 is in the form of a resiliently deformable, conductive metal wire having a curved region 59 which forms at least a segment of the distal end portion of the elongated member 51. The curved region 59 is preformed and, therefore, exists in the unstressed condition (Fig. 2a) of the resilient distal section 55. The distal section has sufficient resilience such that it can be at least partially, and preferably fully, resiliently straightened without materially permanently deforming the curved region. Although various constructions are possible, the curved region 59 preferably terminates at a free distal end 60 of the elongated member 51. Preferably, the radius of the curved region 59 in the unstressed condition is approximately the same as the radius of the curved region 47 of the probe 21. The distal section 55 can project from the port 27 to define an electrode 62 which, in this embodiment, is curved and extends generally transverse to the axis 49. The handpiece 15 is used to mount the probe assembly 13 and to control the length of the electrode 62 and the supply of water and electrical energy to the electrode. The handpiece 15 includes a housing 61 (Figs. 1 and 2) which includes two or more housing sections suitably interconnected as by sonic welding so as to permit assembly of the handpiece. The housing 61, which is preferably constructed of a nonconductive plastic material, has a longitudinally extending slot 63 in an upper wall 65 of the housing and a forward wall 67 with an opening 69 (Fig. 2) . The handpiece 15 also includes a mounting block 71 suitably mounted within- the forward regions of the housing 61, such as by fasteners (not shown) or an adhesive and a slidable controller 73. The mounting block 71, which is constructed of suitable, nonconductive plastic, has a bore 74, a threaded boss 75 at its distal end and an axially extending shaft 77 at its proximal end. The boss 75 and the shaft 77 are both of lesser cross-sectional area than a central main body portion 79 of the mounting block 71. A passage 81 extends axially completely through the mounting block 71.

The boss 75 projects through the opening 69 and out of the housing 61. The probe 21, and more particularly the main tube 31, is received within the passage 81, and the pin 44 is received within the bore 74 to angularly orient the probe 21 and the handpiece 15. The flange 42 of the bushing 39 is received within a counterbore 83 of the mounting block 71. The handpiece 15 also includes a nut 85 threaded onto the boss 75 and having an annular shoulder 87 for engaging a flanged bushing 88 which engages the flange 42 to mount the probe 21 on the handpiece 15.

Although the controller 73 can be of various different constructions, in the embodiment illustrated, it is in the form of an elongated tube of a suitable plastic material having an axial passage 89 which is open at its distal end to slidably receive the shaft 77 and is coupled at its proximal end to a water supply tube 91 which supplies water to the passage 89 from the water supply 19 (Fig. 1) . A seal 94 prevents leakage of the water from the passage 89 into the surrounding regions of the housing 61. The elongated member 51 extends through the passage 81 and into a central region of the passage 89 where it is attached to the controller 73 by three pins 93 (Figs. 2 and 4) .

The controller 73 also has a resilient arm 95 with an upstanding button 97 which projects through the slot 63 and out of the housing 61. The resilient arm 95 terminates in a lug 99 which cooperates with a series of teeth 101 formed on the inside surface of the wall 65 of the housing 61 along one side of the slot 63. By pushing inwardly on the button 97, the arm 95 deflects inwardly to separate the lug 99 from the teeth 101 so that the controller 73 can be slid longitudinally along the shaft 77 to a new position. At the new position, the inward force on the button 97 is released to allow the resilient arm 95 to move upwardly to place the lug 99 into engagement with the adjacent pair of teeth 101 to thereby lock the controller 73 in the new longitudinal position. The handpiece 15 also includes a cut switch 103 and a coagulate switch 105. The cut switch 103 comprises contacts 107 and 109 coupled, respectively, to the power supply 17 (Fig. 1) and to the probe 21 through a conductor 111 and the pin 44 which are in electrical contact in the bore 74. The switch 103 also includes a resilient blade 113 and a button 115. The switch 105 is identical to the switch 103, and corresponding parts are designated by corresponding^' reference numerals. A diaphragm 117 extends between the buttons 115 and the associated blades 113 to provide a seal. The contacts 107 and 109 and the blades 113 of the coagulate switch 105 are electrically coupled to the contact 109 of the cut switch 103 and the power supply 17, respectively. All of the leads to the power supply 17 may extend through a flexible conduit 121.

The elongated member 51 is slidably received within the passage 23 of the probe so that the elongated member can be moved longitudinally of the passage. By moving the elongated member 51 proximally, a distal end portion of the elongated member projects out of the port 27 to define the electrode 62. The length of the electrode 62 can be varied and, in the retracted position, may have a length of zero and may be substantially completely received within the passage 23. In a fully extended position, the electrode may extend, for example, about ten millimeters from the port 27.

To perform lateral release surgery on the knee, an incision is made in the appropriate region of the knee. The distal end portion of the probe is then inserted through the incision with the electrode 62 being in the fully retracted position. This minimizes the cross-sectional dimensions of the portions of the probe assembly 13 which are inserted into the knee and gives the electrode an essentially zero length. Once properly positioned within the knee, the electrode 62 may be extended by depressing the button 97 and moving the controller distally to give the electrode^* the desired length. Indicia 123 (Fig. 1) may be provided on the upper wall 65 of the housing 61 to correlate electrode length with button position.

Electrical energy is then applied to the electrode 62 by closing the cut switch 103. Closure of the cut switch 103 is sensed by. the power supply 17 which then supplies appropriate electrical energy to contacts 107 and 109 of the switch 103 to obtain the desired cutting action at the electrode 62. Closure of the cut switch 103 provides a conductive path to the electrode 62 via the conductor 111, the pin 44, the bushing 39, the main tube 31 and the distal tube 35. The elongated member 51 contacts the interior of the distal tube 35 at various regions, including locations within the curved region 47. If the coagulate switch 105 is closed, the power supply senses such closure and supplies appropriate electrical energy to the contacts 107 and 109 of the coagulate switch to obtain the desired coagulating action at the electrode 62. When the coagulate switch 105 is closed, electrical energy is again supplied to the conductor 111 by virtue of the electrical connection between the contacts 107 and 109 of the switches 103 and 105. The circuit is completed from the electrod.e 62 through the patient and a ground pad (not shown) in a conventional manner. Of course, electrical energy may be supplied to the switches 103 and 105 in any conventional manner. Water, or other non-ionic solution, may be supplied by opening a valve (not shown) to supply water from the water supply 19 through the tube 91 and the passages 89, 81 and 23 and the port 27 to the region adjacent the electrode 62 to wash away debris that may form during the cutting operation. The water from the port 27 to the electrode 62 are essentially coaxial. The water and debris are suctioned off using appropriate equipment (not shown) and conventional techniques. Of course, if water is to be utilized with the device 11, the diameter of the passage 23 must be greater than the diameter of the adjacent regions of the elongated member 51 in order to provide a fluid path for flow of the water.

When the electrode 62 is being extended, the curved region 47 of the probe 21 assists in directing the electrode in the desired direction away from the axis 49, and the surgeon knows what the angular orientation of the electrode will be when it is extended within the knee. The curved region 47 also supports the elongated member 51 against torsional loads, and it cooperates with the curved region 59 of the elongated member 51 to reduce the sliding friction between the probe and the elongated member. Of course, the features of the electrosurgical device of this invention can be employed for electrosurgery on regions of the body other than the knee, if desired.

If desired, the pin 44 can be eliminated and the pins 93 can be spaced sufficiently to allow rotation of the elongated member 51. This would permit angular adjustment of the probe assembly 13 relative to handpiece 15. In this event, the elongated member 51 could rotate, and the curved regions 47 and 59 would cooperate to assist in angularly orienting the electrode 62 so that it would extend from the axis 49 in the same general direction as the curved region 47. Of course, if the pin 44 were eliminated, the conductor 111 would extend through the bore 74 all the way to the bushing 39 to deliver electrical energy to the probe assembly 13.

Although an exemplary embodiment of the invention has been shown and described, many changes, modifications and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of this invention.

Claims

1. An electrosurgical device comprising: an elongated probe having a distal end and a generally longitudinally extending passage opening at a port at the distal end of the probe, said probe being adapted for insertion into an incision; at least a region of the distal end portion of said probe being curved; an elongated member having proximal and distal end portions, at least the distal end portion of the elongated member being resiliently deformable, said elongated member extending within said passage and said distal end portion of the elongated member being extendible out said port in a first direction which is different from the direction of elongation of the probe to form an electrode for electrosurgery with said curved region of the distal end portion of the probe at least assisting in directing the electrode generally in said first direction;- said elongated member and said probe being relatively movable to move the elongated member longitudinally of the passage whereby said electrode can project out of said port for a variable distance in said first direction to enable varying the length of the electrode, said proximal end portion of said elongated member being releasably fixable against movement in said passage whereby the length of the electrode can be releasably fixed; and means for coupling the electrode to a source of electrical energy.

2. An electrosurgical device as defined in claim 1 wherein the curved region of the distal end portion of the probe terminates substantially at said distal end.

3. An electrosurgical device as defined in.claim 1 wherein the maximum overall dimension of the distal end portion of the probe as viewed in side elevation is no more than about two millimeters.

4. An electrosurgical device as defined in claim 1 wherein at least a region of the distal end portion of the elongated member is curved in the unstressed condition.

5. An electrosurgical device as defined in claim 4 wherein the electrode terminates in a free distal end.

6. An electrosurgical device as defined in claim 4 wherein the radius of said curved region of the distal end portion of the elongated member in the unstressed condition is approximately the same as the radius of said curved region of the probe.

7. An electrosurgical device as defined in claim 4 wherein said curved region of the elongated member is at least partially resiliently straightened by said probe when said curved region of the elongated member is in said passage of said probe.

8. An electrosurgical device as defined in claim 1 wherein said elongated member includes a proximal section and a distal section, said proximal and distal sections being joined together, and said proximal section being stiffer than said distal section.

9. An electrosurgical device as defined in claim 1 including a handpiece adapted to be manually grasped, means for releasably attaching the probe to the handpiece with at least a portion of the proximal end portion of the elongated member extending into the handpiece, and said handpiece including means for moving the elongated member to vary the length of the electrode.

10. An electrosurgical device as defined in claim 9 wherein said handpiece includes a mounting block having a bore therein, said coupling means includes a conductor and a pin on said probe, said conductor and said pin are at least partially received within said bore and are in electrical contact to provide electrical energy to the probe, and at least regions of said probe being electrically conductive and engageable with the elongated member.

11. An electrosurgical device as defined in claim 9 wherein said moving means includes a movable member, the proximal end portion of the elongated member being coupled to said movable member and movable therewith in both directions to extend and retract the electrode.

12. An electrosurgical device comprising: an elongated probe having . a distal end and a generally longitudinally extending passage opening at a port 18

adjacent the distal end of the probe, said probe being 5 adapted for insertion into an incision; an elongated member having proximal and distal end portions, at least said distal end portion of said elongated member being resiliently deformable, at least a region of said distal end portion of said elongated member being curved 10 in the unstressed condition; said elongated member extending within said passage and at least a portion of said distal end portion of the elongated member being extendible out said port in a first direction which is different from the direction of elongation 15 of the probe to form an electrode for electrosurgery with the curved region of the elongated member at least assisting in' causing the electrode to extend in said first direction; said elongated member and said probe being relatively movable to move the elongated member 20. longitudinally of the passage whereby said distal end portion can project out said port for a variable distance in said first direction to enable varying the length of the electrode, said proximal end portion of said elongated member being releasably fixable against movement in said passage 5 whereby the length of the electrode can be releasably fixed; and means for coupling the electrode to a source of electrical energy.

13. An electrosurgical device as defined in claim 12 wherein said curved region of the elongated member is at least partially resiliently straightened by said probe when said curved region of the elongated member is in said passage 5 of said probe.

14. An electrosurgical device as defined in claim 12 wherein said curved region of said elongated member terminates substantially at the distal end of the elongated member.

15. An electrosurgical device as defined in claim 12 wherein the elongated member includes a proximal section and a distal section, said proximal section being joined to said distal section, and said proximal section being stiffer than said distal section.

16. An electrosurgical device as defined in claim 12 wherein at least a segment of said electrode is curved when the electrode is fully extended from said port.

17. An electrosurgical device as defined in claim 12 including conduit means for supplying a liquid to said passage for washing away debris which would impair the electrosurger .

18. An electrosurgical device as defined in claim 12 wherein at least the outer surface of the distal end portion of said probe is of electrical insulating material.

19. An electrosurgical device as defined in claim 12 including a handpiece adapted to be manually grasped, means for attaching the probe to the handpiece with at least a portion of the proximal, end portion of the elongated member extending into the handpiece, and said handpiece including means for moving the elongated member to vary the length of the electrode. 20

20. An electrosurgical device as defined in claim 19 wherein said handpiece includes a mounting block having a bore therein, said coupling means includes a conductor and a pin on said probe, said conductor and said pin are at least partially received within said bore and are in electrical contact to provide electrical energy to the probe, and at least regions of said probe being electrically conductive and engageable with the elongated member.

21. An electrosurgical device as defined in claim 19 wherein said moving means includes a movable member, the proximal end portion of the elongated member being coupled to said movable member and movable therewith in both directions to extend and retract the electrode.

22. An electrosurgical device comprising: an elongated probe having a distal end and a generally longitudinally extending passage opening at a port adjacent the distal end of the probe, said probe being adapted for insertion into an incision; an elongated member having proximal and distal end portions, at least the distal end portion of the elongated member being resiliently deformable, said elongated member extending within said passage and said distal end portion of the elongated member being extendible out of said port to form an electrode for electrosurgery, said probe terminating in a free distal end; means for causing said electrode to be extendible out of said port in a first direction which is different from the direction of elongation of the probe; 21

said elongated member and said probe being relatively movable to move the elongated member longitudinally of the passage whereby said electrode can project out of said port for a variable distance in said first direction to enable varying the length of the electrode, said proximal end portion of said elongated member being releasably fixable against movement in said passage whereby the length of the electrode can be releasably fixed; and means for coupling the electrode to a source of electrical energy.

23. An electrosurgical device as defined in claim 22 wherein said causing means includes at least a region of the distal end portion of said probe being curved.

24. An electrosurgical device as defined in claim 22 wherein said causing means includes at least a region of the distal end portion of the elongated member being curved in the unstressed condition.

25. An electrosurgical device as defined in claim 24 wherein said causing means includes at least a region of the distal end portion of said probe being curved.