DE102017100298B4 - electrosurgical device - Google Patents

Abstract

Surgical instrument (1) which
a handle (10), and
a pair of curved first and curved second jaws (3802, 3803), one or both of the curved jaws (3802, 3803) including a curved slot (3811) to form a curved path therebetween,
a blade assembly (340) arranged for longitudinal movement to a deployed state within the curved path, the blade assembly (340) comprising a cutting blade (340) at its distal end,
a trigger mechanism disposed on the handle (10) and movable between a first position and a second position, wherein movement of the trigger mechanism from its first position to its second position causes longitudinal movement of the blade assembly (340) to its deployed position,
characterized in that the blade assembly (340) has at least three adjacent regions, the first distal region having a first longitudinally extending slot (4702; 4706) and the second central region having a second longitudinally extending slot (4704; 4708) that is shorter than and flush with the first longitudinally extending slot (4702; 4706), whereby the first distal region has greater lateral flexibility, ie greater lateral bending, than the second central region, and the second central region has greater lateral flexibility than the third proximal region.

Description

field of the invention

Embodiments of the present invention described herein relate to an electrosurgical device, and more particularly to an electrosurgical forceps, wherein a mechanical cutting blade provides a tissue cutting function in combination with electrosurgical electrodes which provide a tissue coagulation or sealing action.

Background of the invention and state of the art

Electrosurgical instruments offer advantages over conventional surgical instruments as they can be used for the coagulation and sealing of tissues. Such a state-of-the-art arrangement is US 2015 / 0 223 870 A1 known, wherein an endoscopic bipolar forceps is described comprising a housing and a shaft, the shaft having an electrosurgical end effector assembly at its distal end which includes two jaw members for grasping tissue therebetween. Each jaw member is adapted to be connected to an electrosurgical energy source, thereby enabling sealing of tissue held between the jaw members. A drive assembly is received in the housing to move the jaw members. A movable handle is also provided such that movement of the handle actuates the drive assembly to move the jaw members relative to one another. A knife channel is part of the end effector to enable forward and backward movement of a cutting blade in the knife channel, in turn enabling cutting of tissue.

Further arrangements according to the state of the art include the following: US 2014/0 155 878 A1 , US 2012 / 0 215 215 A1 , US 5 730 740 A , US 5 104 397 A , US 4 800 880 A , WO 98 / 14 124 A1 , US 2012 / 0 109 186 A1 , US 5 352 235 A , WO 2014 / 074 807 A1 , US 7 846 161 B2 , WO 2008 / 024 911 A2 , US 5 776 130 A , US 6 039 733 A , US 6 179 834 B1 , US 7 131 971 B2 , US 7 766 910 B2 , EP 2 628 459 A2 , US 2014 / 0 221 999 A1 , US 7 083 618 B2 , US 2009 / 0 248 020 A1 , US 2015 / 0 209 103 A1 , US 5 797 938 A and US 7 101 373 B2 .

Brief Description of the Invention

Embodiments of the present invention provide an improved surgical instrument having an end effector attached to the end of an elongated shaft extending from a handle. The end effector is capable of performing a number of different operations including grasping, cutting and sealing and/or coagulating tissue, and one of the functions is controlled by a trigger mechanism contained within the handle. In some embodiments, the end effector includes a pair of curved jaw members and a cutting blade assembly having a cutting blade at its distal end. The trigger assembly is arranged to drive the cutting blade assembly longitudinally within the elongated shaft such that the cutting blade protrudes between the jaw members. To assist the trigger mechanism in pushing the cutting blade assembly along the curved jaws, the distal end of the cutting blade has a graduated flexibility so that it can more easily bend according to the shape of the jaw members. The distal end of the cutting blade may also be provided with a low-friction coating so that it can slide more easily between the jaw elements.

A first aspect provides a surgical instrument which
includes a handle, as well as
a pair having a curved first and a curved second jaw, one or both of the curved jaw members including a curved slot to form a curved path therebetween,
a cutting blade assembly arranged for longitudinal movement in a deployed position within the curved path, the cutting blade assembly comprising a cutting blade at its distal end,
a trigger mechanism disposed on the handle and movable between a first position and a second position, wherein movement of the trigger mechanism from its first position to its second position causes longitudinal movement of the cutting blade assembly to its deployed position,
characterized in that the cutting blade assembly is formed in at least three adjacent regions, a first distal region having a first longitudinally extending slot and the second intermediate region having a second longitudinally extending slot which is shorter than and aligned with the first longitudinally extending slot, whereby the first distal region has a greater lateral flexibility, ie a greater lateral bending capacity, than that of a second intermediate region, the second intermediate region having a greater lateral flexibility than the third proximal region.

As such, the trigger mechanism is required to push the cutting blade along a curved path, which contributes to frictional forces opposing the cutting blade movement. This can therefore be reduced by making the cutting blade progressively more flexible, i.e. more pliable, towards the distal end, so that it is easier for the cutting blade to follow the curved path between the jaws.

The cutting blade assembly may be in the form of a rod having a thickness substantially less than either its width or its length.

The slot in the first region and the second, middle region may also be adjacent to each other.

The openings may be located within the body of the cutting blade assembly.

The thickness of the cutting blade assembly may be less in the first, distal region compared to its thickness in the second, middle region.

In some arrangements, at least a portion of the cutting blade assembly is coated with a low-friction coating.

The cutting blade assembly may also be configured such that the first region is disposed distally of the second region such that the second region is at least partially within the curved path formed by the jaws when the cutting blade assembly is in its deployed position.

In some arrangements, the handle may further include an actuating mechanism movable between a first position and a second position, wherein moving the actuating mechanism from its first position to its second position causes at least one of the curved jaw members to move relative to the other from a first open position in which the jaw members are arranged in a spaced relationship relative to one another, to a second closed position in which the curved jaw members cooperate to engage tissue therebetween.

Also described herein is a surgical instrument which:
includes a handle, as well as
a pair having a curved first and a curved second jaw member, one or both of the curved jaw members including a curved slot to form a curved path therebetween,
a cutting blade assembly arranged for longitudinal movement within the curved path, the cutting blade assembly comprising a cutting blade at its distal end,
a trigger mechanism disposed on the handle and movable between a first position and a second position, wherein movement of the trigger mechanism from its first position to its second position causes movement of the cutting blade assembly in the longitudinal direction,
characterized in that at least a portion of the cutting blade assembly is coated with a low-friction coating.

As described above, the trigger mechanism requires the cutting blade to slide along a curve, thus contributing to the frictional forces opposing the cutting blade movement. These frictional forces can therefore be reduced by coating the cutting blade with a low-friction material, making it easier for the cutting blade to follow the curved path between the jaws.

In some arrangements, the cutting blade assembly may be coated using a physical vapor deposition (PVD) process. Alternatively, the cutting blade assembly may be coated using a chemical vapor deposition process. Suitable coatings may include low friction polymer composites such as PTFE.

In some arrangements, the handle may further include an actuating mechanism movable between a first position and a second position, wherein moving the actuating mechanism from its first position to its second position causes at least one of the curved jaw members to move relative to the other from a first open position in which the jaw members are disposed in a spaced relationship relative to one another to a second closed position in which the curved jaw members cooperate to engage tissue therebetween.

Short description of the drawings

• 1 eine Seitenansicht eines elektrochirurgischen Instruments gemäß einer Ausführungsform der vorliegenden Erfindung ist;
• 2 eine Seitenansicht eines Griffs des elektrochirurgischen Instruments gemäß der Ausführungsform der vorliegenden Erfindung ist;
• 3 eine Explosionsdarstellung eines elektrochirurgischen Instruments gemäß der Ausführungsform der vorliegenden Erfindung ist;
• 4 eine Querschnittsansicht des Klemmmechanismus des elektrochirurgischen Instruments aus 3 in geöffneter Anordnung zeigt;
• 5a eine Querschnittsansicht des Klemmmechanismus des elektrochirurgischen Instruments aus 3 in geschlossener Anordnung zeigt;
• 5b eine Querschnittsansicht des Klemmmechanismus des elektrochirurgischen Instruments aus 3 in einer geschlossenen Anordnung mit darin eingeklemmtem Gewebe zeigt;
• 6 eine Querschnittsansicht eines Teils des Klemmmechanismus des elektrochirurgischen Instruments aus 3 zeigt;
• 7 eine perspektivische Ansicht des Klemmmechanismus des elektrochirurgischen Instruments aus 3 zeigt;
• 8a-f das Zusammenfügen eines Teils des elektrochirurgischen Instruments aus 3 zeigen;
• 9a-b Querschnittsansichten eines Teils des elektrochirurgischen Instruments aus 3 sind;
• 10a-c ein Schneidklingenführungsteil des elektrochirurgischen Instruments aus 3 zeigen;
• 11 ein Einrastteil des elektrochirurgischen Instruments aus 3 zeigt;
• 12 ein Schneidklingenwinkelausrichtungsteil des elektrochirurgischen Instruments aus 3 zeigt;
• 13a-b Querschnittsansichten des Schneidklingenwinkelausrichtungsteils des elektrochirurgischen Instruments aus 3 zeigen;
• 14a-b ein Schneidklingenwinkelsteuerradteil des elektrochirurgischen Instruments aus 3 zeigen;
• 15a-b die Drehbewegung des Schneidklingenwinkelsteuerrads des elektrochirurgischen Instruments aus 3 zeigen;
• 16a-d die Drehbewegung des Endeffektors des elektrochirurgischen Instruments aus 3 zeigen;
• 17 eine Querschnittsansicht des elektrochirurgischen Instruments aus 3 zeigt und einen Verdrahtungspfad veranschaulicht;
• 18a-b Details eines elektrischen Verdrahtungspfads zeigen, der in dem elektrochirurgischen Instrument aus 3 verwendet wird;
• 19 weitere Details eines elektrischen Verdrahtungspfads zeigt, der in dem elektrochirurgischen Instrument aus 3 verwendet wird;
• 20a-b Seitenansichten eines Teils des Schneidmechanismus des elektrochirurgischen Instruments aus 3 sind;
• 21 eine Querschnittsansicht eines Teils des Schneidmechanismus des elektrochirurgischen Instruments aus 3 ist;
• 22 eine Querschnittsansicht eines anderen Teils des Schneidmechanismus des elektrochirurgischen Instruments aus 3 zeigt;
• 23 eine teilweise transparente perspektivische Ansicht des Schneidmechanismus des elektrochirurgischen Instruments aus 3 ist;
• 24a-c das Zusammenfügen eines Teils des Schneidmechanismus des elektrochirurgischen Instruments aus 3 zeigen;
• 25a-c Querschnittsansichten des Schneidmechanismus und des Klemmmechanismus des elektrochirurgischen Instruments aus 3 zeigen;
• 26a-f Querschnittsansichten sind, die den Betrieb des Einrastmechanismus des elektrochirurgischen Instruments aus 3 veranschaulichen;
• 27 ein Diagramm ist, dass den Schneidmechanismus des elektrochirurgischen Instruments aus 3 veranschaulicht;
• 28a-b Strichzeichnungen sind, die den Schneidmechanismus des elektrochirurgischen Instruments aus 3 veranschaulichen;
• 29a-b ein Schneidklingenwinkelausrichtungsteil des elektrochirurgischen Instruments aus 3 zeigen;
• 30 eine perspektivische Ansicht eines Teils des Klemmmechanismus des elektrochirurgischen Instruments aus 3 ist;
• 31 eine Teilquerschnittsansicht des Schneidmechanismus und des Klemmmechanismus des elektrochirurgischen Instruments aus 3 ist;
• 32 eine Teilquerschnittsansicht des Schneidmechanismus und des Klemmmechanismus des elektrochirurgischen Instruments aus 3 ist;
• 33 das Schneidklingenwinkelsteuerradteil und den Elektrodensteuerschalter des elektrochirurgischen Instruments aus 3 zeigt;
• 34 das Schneidklingenwinkelsteuerradteil des elektrochirurgischen Instruments aus 3 zeigt;
• 35a-b den Griff des elektrochirurgischen Instruments aus Fig. zeigen, gehalten durch Benutzer mit unterschiedlich großen Händen;
• 36a-c die Rotationsbewegung des Endeffektors des elektrochirurgischen Instruments aus 3 zeigen;
• 37 die Rotationsbewegung des Schneidklingenwinkelsteuerrads des elektrochirurgischen Instruments aus 3 zeigt;
• 38 eine schematische perspektivische Ansicht eines Beispiels für einen Endeffektor ist;
• 39 eine vergrößerte perspektivische Ansicht eines Teils des Endeffektors aus 38 ist;
• 40 eine schematische Querschnittsansicht eines Teils des Endeffektors aus 38 ist;
• 41 eine schematische perspektivische Ansicht eines alternativen Endeffektors ist;
• 42 eine vergrößerte perspektivische Ansicht eines Teils des Endeffektors aus 41 ist,
• 43 eine schematische Querschnittsansicht eines Teils des Endeffektors aus 41 ist,
• 44 eine schematische Querschnittsansicht eines Teils eines weiteren alternativen Endeffektors ist;
• 45 eine Darstellung eines elektrochirurgischen Systems ist, das einen Generator und ein Instrument gemäß den Ausführungsformen der Erfindung umfasst;
• 46 ferner ein Einrastteil des elektrochirurgischen Instruments aus 3 zeigt und
• 47a-e das distale Ende der in dem elektrochirurgischen Instrument aus 3 verwendeten Schneidklinge veranschaulicht.

Embodiments of the invention will now be further described by way of example only and with reference to the accompanying drawings ben, wherein like reference numerals in the drawings refer to like parts and wherein:

• 1 is a side view of an electrosurgical instrument according to an embodiment of the present invention;
• 2 is a side view of a handle of the electrosurgical instrument according to the embodiment of the present invention;
• 3 is an exploded view of an electrosurgical instrument according to the embodiment of the present invention;
• 4 a cross-sectional view of the clamping mechanism of the electrosurgical instrument 3 in open configuration;
• 5a a cross-sectional view of the clamping mechanism of the electrosurgical instrument 3 in closed arrangement;
• 5b a cross-sectional view of the clamping mechanism of the electrosurgical instrument 3 in a closed arrangement with tissue trapped within;
• 6 a cross-sectional view of a portion of the clamping mechanism of the electrosurgical instrument of 3 shows;
• 7 a perspective view of the clamping mechanism of the electrosurgical instrument from 3 shows;
• 8a -f the assembly of a part of the electrosurgical instrument from 3 show;
• 9a -b Cross-sectional views of a portion of the electrosurgical instrument from 3 are;
• 10a -c a cutting blade guide part of the electrosurgical instrument made of 3 show;
• 11 a locking part of the electrosurgical instrument 3 shows;
• 12 a cutting blade angle alignment part of the electrosurgical instrument made of 3 shows;
• 13a -b Cross-sectional views of the cutting blade angle alignment part of the electrosurgical instrument from 3 show;
• 14a -b a cutting blade angle control wheel part of the electrosurgical instrument made of 3 show;
• 15a -b the rotational movement of the cutting blade angle control wheel of the electrosurgical instrument 3 show;
• 16a -d the rotational movement of the end effector of the electrosurgical instrument 3 show;
• 17 a cross-sectional view of the electrosurgical instrument 3 and illustrates a wiring path;
• 18a -b Show details of an electrical wiring path used in the electrosurgical instrument of 3 is used;
• 19 shows further details of an electrical wiring path used in the electrosurgical instrument 3 is used;
• 20a -b Side views of a part of the cutting mechanism of the electrosurgical instrument from 3 are;
• 21 a cross-sectional view of a portion of the cutting mechanism of the electrosurgical instrument of 3 is;
• 22 a cross-sectional view of another part of the cutting mechanism of the electrosurgical instrument 3 shows;
• 23 a partially transparent perspective view of the cutting mechanism of the electrosurgical instrument from 3 is;
• 24a -c the assembly of a part of the cutting mechanism of the electrosurgical instrument from 3 show;
• 25a -c Cross-sectional views of the cutting mechanism and the clamping mechanism of the electrosurgical instrument from 3 show;
• 26a -f are cross-sectional views illustrating the operation of the locking mechanism of the electrosurgical instrument from 3 illustrate;
• 27 a diagram that shows the cutting mechanism of the electrosurgical instrument 3 illustrated;
• 28a -b are line drawings showing the cutting mechanism of the electrosurgical instrument from 3 illustrate;
• 29a -b a cutting blade angle alignment part of the electrosurgical instrument made of 3 show;
• 30 a perspective view of a portion of the clamping mechanism of the electrosurgical instrument of 3 is;
• 31 a partial cross-sectional view of the cutting mechanism and the clamping mechanism of the electrosurgical instrument from 3 is;
• 32 a partial cross-sectional view of the cutting mechanism and the clamping mechanism of the electrosurgical instrument from 3 is;
• 33 the cutting blade angle control wheel part and the electrode control switch of the electrosurgical instrument 3 shows;
• 34 the cutting blade angle control wheel part of the electrosurgical instrument 3 shows;
• 35a -b show the handle of the electrosurgical instrument of Fig. held by users with different sized hands;
• 36a -c the rotational movement of the end effector of the electrosurgical instrument 3 show;
• 37 the rotational movement of the cutting blade angle control wheel of the electrosurgical instrument 3 shows;
• 38 is a schematic perspective view of an example of an end effector;
• 39 an enlarged perspective view of a portion of the end effector 38 is;
• 40 a schematic cross-sectional view of a part of the end effector 38 is;
• 41 is a schematic perspective view of an alternative end effector;
• 42 an enlarged perspective view of a portion of the end effector 41 is,
• 43 a schematic cross-sectional view of a part of the end effector 41 is,
• 44 is a schematic cross-sectional view of part of another alternative end effector;
• 45 is an illustration of an electrosurgical system including a generator and an instrument according to embodiments of the invention;
• 46 Furthermore, a locking part of the electrosurgical instrument made of 3 shows and
• 47a -e the distal end of the in the electrosurgical instrument from 3 used cutting blade.

Description of the embodiments

An embodiment of the invention will now be described. First, a brief overview of the overall embodiment will be given, followed by detailed descriptions of certain aspects thereof.

1. Overview of the structure of the instrument

1 shows an electrosurgical instrument 1 according to an example of the present invention. The instrument 1 includes a proximal handle 10, an outer shaft 12 extending in a distal direction from the proximal portion of the handle 10, and a distal end effector assembly 14 attached to a distal end of the outer shaft 12. The end effector assembly 14 may, for example, be a set of opposing jaws arranged to open and close and include one or more electrodes disposed on or formed by their opposing inner surfaces and which, in use, have terminals for receiving a radio frequency (RF) electrosurgical signal for sealing or coagulating tissue. The jaws are further provided with a slot or other opening in the opposing inner surfaces through which a mechanical cutting blade or the like may protrude upon activation by the user. In use, the handle 10 is activated by the user in a first manner to clamp tissue between the jaws 14 and in a second manner to supply RF current to the electrodes to coagulate the tissue. The jaws 14 may be curved so that the active elements of the instrument 1 are always visible. This is important in vessel sealing devices which are used to operate on regions of the body which make it difficult for the user to see the device during use. The handle 10 may be activated by the user in a third manner to cause the cutting blade to protrude between the jaws 14, thereby cutting tissue clamped between them. After the required cutting and sealing has been completed, the user may release the tissue from the jaws 14.

The handle 10 comprises, as in 2 shown, a housing 20 made of two shell moldings 300, 302, which houses all the components required for actuating and rotating the jaws 14, coagulating and cutting tissue. The shell moldings in the assembled device are ultrasonically welded after the internal components are arranged inside them. The handle 10 includes a drive handle 22 for clamping tissue between the jaws 14, a trigger 24 for cutting the tissue, a switch 26 for activating and Deactivating the HF supply to the electrodes in the jaws 14 for coagulation of tissue, and a rotary wheel 28 for rotating the jaws 14 to reach tissue at different angles. The handle 10 is designed so that the instrument 1 and all its functions can be operated with just one hand, with all operating mechanisms being easily accessible.

3 shows all features of instrument 1 required to perform its functions, including those housed in the two shell moldings 300, 302 of housing 20. A clamping mechanism is actuated using drive handle 22 to clamp tissue between jaws 14. Drive handle 22 further includes a handle collar ring 304 which includes a hinge 306 which acts as a pivot point about which drive handle 22 rotates. For example, hinge 306 may be two outwardly directed pins which engage corresponding moldings 308 formed integrally with shell moldings 300, 302 to provide an anchor point about which drive handle 22 rotates. The clamping mechanism further includes a collar ring molding 310, a spring 312 and an inner molding 314 as shown in 4 to 7 , all lined up along a drive shaft 316.

The handle collar ring 304 includes an opening 318 in which the collar ring molding 310 is received. The opening 318 has a larger diameter at the top than at the bottom, with the collar ring molding 310 arranged to be received in the lower part of the opening 318, as 8a When assembled, the collar ring molding 310 easily fits through the larger portion of the opening 318 so that the handle collar ring 304 is received between two flange portions 800, 802, as 8b -c show. As 8d , the handle collar ring 304 is then pushed upward to engage the smaller portion of the opening 318 with the collar ring molding 310. With the hinge 306 connected to the hinge moldings 308 within the housing 20, the collar ring molding 310 is held in the lower portion of the opening 318 where it can rotate freely within the opening 318.

The collar ring molding 310, the spring 312 and the inner molding 314 are, as in 6 shown, are held between protruding elements 600, 602 such that they cannot move axially beyond those protruding elements 600, 602. In this regard, the protruding elements 602 at the proximal end of the drive shaft 316 are compressible to permit the drive shaft 316 to pass through a channel 604 in the proximal end of the inner mold part 314. The drive shaft 316 is pushed through the channel 604 until it reaches an opening 606, at which point the protruding elements 602 are no longer compressed so that they lie flush against the walls of the drive shaft 316. Instead, the protruding elements 602 are fanned out and press against the walls of the opening 606 so that the width of the protruding elements 602 extends beyond the diameter of the channel 604. Consequently, the drive shaft 316 cannot be retracted through the channel 604 and is locked.

The spacing between the protruding elements 600, 602 is selected such that the spring 312 is at least partially compressed between the collar ring molding 310 and the inner molding 314. This pre-compression is essential to ensure that the correct clamping load is applied when the clamping mechanism is activated, as described in more detail below. Both the collar ring molding 310 and the inner molding 314 include cavities 608, 610 into which the spring 312 extends. In particular, a substantial portion of the length of the collar ring molding 310 accommodates the spring 312. This arrangement allows for a longer spring 312, which is important to ensure that the spring 312 never reaches its block length during use.

The main body of the drive shaft 316 is located within the outer shaft 12, with the distal end of the drive shaft 316 being connected to both the distal end of the outer shaft 12 and the jaws 14. The drive shaft 316 moves axially within the outer shaft 12 and by this axial movement the jaws 14 are moved from an open to a closed position, as shown in 4 and 5a The drive shaft 316 is coupled to the jaws 14, for example, by a drive pin 400 in a cam slot 402, with movement of the drive pin 400 in the cam slot 402 moving the jaws 14 between the open and closed positions. The connection between the drive shaft 316, the outer shaft 12 and the jaws 14 is such that rotational movement of the drive shaft 316 is transmitted to the outer shaft 12 and the jaws 14.

The outer shaft 12 and the drive shaft 316 are connected at another point by a shaft molding 320. The shaft molding 320 is received in a socket 322 of the housing 20 and thus connects the outer shaft 12 to the housing 20. The outer shaft 12 is attached to the shaft molding 320 by any suitable means, such as by locking projections 900, which cooperate with corresponding grooves 902 in the shaft molding 320, as in 9b The drive shaft 316 is guided through an opening (not shown) adapted to the T-shaped cross section of the drive shaft 316 through the body of the shaft molding 320, as shown by 10a The shaft molding 320 is arranged so that it can rotate freely in the socket 322. The shaft molding 320 can, for example, comprise cylindrical flange elements 904, 906 which rotate in concentric mating surfaces 908, 910 provided in the shell moldings 300, 302. Thus, the shaft molding 320 rotates with the drive shaft 316, which in turn transmits this rotational movement to the outer shaft 12 and the clamping jaws 14. The shaft molding 320 thus functions as a rotational guide and axial guide for the drive shaft 316.

The drive handle 22 includes a latching element 324 arranged to cooperate with a latching molding 326 present in the proximal end 328 of the housing 20. The latching molding 326 may be engaged by any suitable means, such as by a molding pin 330 formed integrally with one of the shell moldings 300, 302, as shown in 3 or simply by the molding walls 1100 which are integrally formed with the shell molding 300, as in 11 shown, are held in place. When the drive handle 22 is driven toward the housing 20 to close the jaws 14, the latching element 324 enters the housing 20 via an opening 1102 and engages the latching molding 326 to hold the drive handle 22 in that position. As shown in 26a to 26f As can be seen, the latching molding 326 comprises a two-way spring 1104 and a cam path 1106 along which the latching element 324 moves. As in 46 As shown, the latch mechanism may also include an override component 4600 to allow the user to manually release the latch member 324 if it becomes stuck, and a locking component 4602 to disable the latch mechanism entirely. The override component 4600 and the locking component 4602 may be provided on the latch molding 326 or integrated into the interior of the housing 20.

As described above, the handle 10 further comprises a rotary wheel 28, wherein the rotary wheel 28 is arranged to enclose the inner mold part 314. For this purpose, the rotary wheel 28 and the inner mold part 314 have interlocking elements 1200, 1202, as can be seen from 12 These interlocking elements 1200, 1202 connect in such a way that the rotary wheel 28 and the inner mold part 314 rotate together, while still allowing axial movement of the inner mold part 314 within the rotary wheel 28, as can be seen from 13a -b. Thus, rotation of the rotary wheel 28 causes rotation of the inner mold part 314, which consequently causes rotation of the drive shaft 316 and the collar ring mold part 310. For stability reasons, the rotary wheel 28 includes cylindrical surfaces 1204 which slide in rotation on inner counter surfaces (not shown) which are integrally formed with respect to the shell mold parts 300, 302.

To allow a user to rotate the jaws 14, the housing 20 has two openings 332, 334 through which notched portions 336 of the rotary wheel 28 extend. The two openings 332, 334 are opposite each other on either side of the handle and are trapezoidal in shape. In particular, the trapezoidal openings have parallel sides that are at right angles to the longitudinal axis of the handle, and one of the parallel sides may be longer than the other, with the longer side at the front end of the opening and the shorter side at the rear end of the opening. The notched portions 336 are suitably beveled so that they fit well with the thumb or fingers of the user. To this end, the notched portions 336 are cut at an angle to the plane of rotation, as shown in 14a -b. In particular, the angle of the beveled part of the notched sections should substantially correspond to the angle of the outer housing in the region of the rotary wheel 28.

The rotary wheel 28 also comprises at least one stop element 1500 for limiting the degree of rotation, as in 15a -b. The stop element 1500 interacts with stop parts 1502, 1504 that are integrally formed with the housing 20. When the rotary wheel 28 is rotated, the stop element 1500 is blocked by the stop parts 1502, 1504, thereby preventing further rotation. The stop parts 1502, 1504 may, for example, limit the rotation of the rotary wheel to 270°. Similarly, the shaft molding 320 also includes a stop element 1600 that interacts with stop parts 1602, 1604 that are integrally formed with the housing 20, as shown in 16a -d. The stop element 1600 of the shaft molding 320 and its corresponding stop part 1602, 1604 are aligned with respect to the stop element 1500 of the rotary wheel 28 and its corresponding stop parts 1502, 1504 so that the rotation is restricted to the same extent. This means that when the rotary wheel 28 rotates, the radial point at which the stop element 1500 is blocked on the rotary wheel 28 coincides with the radial point at which the stop element 1600 is blocked on the shaft molding 320. In 15b and 16a For example, the clamping jaws 14 were moved from a neutral orientation (which is 16b shown) is rotated 90° counterclockwise. This freedom of rotation means that the user can capture tissue from different angles without having to rotate the entire instrument 1.

As described above, the switch 26 is provided to enable or disable the RF signal applied to the electrodes in the jaws 14 via suitable circuitry, such as two ingress-proof switches on a small printed circuit board (PCB) 338. As can be seen from 17 , the PCB 338 is connected to a connecting cable 1700 to receive the RF output signal from a generator (not shown) and to electrical leads 1702, 1704 to supply the RF current to the electrodes in the jaws 14, such as a lead for the active electrode and a lead for the counter electrode. As shown in 17 and 18ab As shown, the leads 1702, 1704 are wrapped beneath and around the shaft molding 320 before entering a guide slot 1800 in the interior cavity 1802 of the shaft molding 320 and extending down the outer shaft 12. Wrapping the leads 1702, 1704 around the shaft molding 320 in this manner keeps the leads 1702, 1704 in a compact arrangement to allow for easy assembly while allowing the drive shaft 316 to rotate. In doing so, the leads 1702, 1704 are unwound and rewound with the rotation of the drive shaft 316. In addition, one of the shell moldings 300 also includes two molded compartments 1900, 1902 arranged in sequence to receive the line contacts 1904, 1906 that connect the active lines and return lines 1702, 1704 to the wiring 1908, 1910 of the intrusion-protected switches 338. The opposite shell molding 302 includes corresponding rib members (not shown) to retain the contacts 1904, 1906 in the compartments 1900, 1902. Thus, the two line contacts 1904, 1906 are longitudinally separated such that only one contact can pass through each compartment 1900, 1902, thereby providing a physical barrier between each compartment 1904, 1906 and each line. This eliminates the risk of damage to the insulation on one of the leads caused by the contacts 1904, 1906 and at the same time protects the contacts 1904, 1906 themselves from fluids that may run along the outer shaft 12 and into the housing 20.

Referring to the cutting mechanism, a cutting blade 340 is provided for cutting tissue clamped between the jaws 14 in a central path 342 along the length of the drive shaft 316. The mechanism for actuating the cutting blade 340 along the path 342 and between the jaws 14 is actuated via the trigger 24. The trigger 24 actuates a drive assembly consisting of a trigger molding 344, a blade drive molding 346, a blade collar ring molding 348, a tension spring 350 and a blade molding 352. The drive assembly is disposed between the shaft molding 320 and the handle collar ring 304 of the clamping mechanism. As shown in 20a -b, the drive assembly functions as an offset slider crank mechanism by which the force exerted by the user on the trigger 24 is converted into axial movement of the blade molding 352 along the drive shaft 316, which in turn drives the attached cutting blade 340.

As from 21 , 22 and 23 As can be seen, the blade molding 352 is arranged to be received in the blade collar ring molding 348. As 22 shows, the blade collar ring molding 348 includes a lip edge 2200 that engages a recess 2202 that extends around the periphery of the blade molding 352. As 23 , the blade molding 352 has a T-shaped opening 2300 for receiving the drive shaft 316 and the cutting blade 340. The blade molding 352 further includes an inner cutout 2100, as 21 shows, for the proximal end of the cutting blade 340, wherein the end of the cutting blade 340 is shaped to fit the inner cutout 2100 of the blade molding 352 to allow easy assembly, as in 24a -c. The blade molding 352 is independently rotatable relative to the blade collar ring molding 348 so that the two moldings can rotate concentrically. Consequently, the blade molding 352 is able to rotate with the drive shaft 316.

The jaws 14 may be curved as described above. In order to allow the cutting blade 340 to slide around the curved path while retaining sufficient cutting ability, the frictional force of the cutting blade 340 in the curved path must be minimized. The frictional force is a product of the coefficient of friction of the cutting blade 340 in the path 342 and the force exerted on the walls of the path 342 by the bending of the cutting blade 340. This frictional force may be reduced, for example, by adding a friction reducing coating to both sides of the cutting blade and/or preferably weakening the cutting blade 340 to grade the flexibility of the distal end of the cutting blade so that it can bend along the path 342 while simultaneously being in Cutting force direction remains rigid. The preferred weakening can be achieved, for example, by providing one or more openings 354 in the distal end, as in 3 and 47a -c, or by graduating the thickness of the cutting blade 340, as in 47d Alternatively, as in 47e As shown, patterned laser cutouts 4712 or chemical etching may be applied in the distal end to adjust the bending stiffness along the blade length, wherein the spacing of such cutouts may be constant or may increase gradually from the distal to the proximal end.

During use, blood and tissue may accumulate in the distal end of the instrument 1. In particular, blood and tissue may cause the cutting blade 340 to become stuck inside the drive shaft 316. Therefore, the distal end of the drive shaft 316 may include cut-out portions 1000 to reduce the surface of the drive shaft 316 to which blood and tissue may adhere, as shown in 10b -c. The cut-out portions may, for example, be such that the distal end comprises two side walls without a base or that the distal end comprises a base with forked side walls.

2. Operation of the instrument

After describing the overall structure of the device, the entire operation of the electrosurgical instrument 1 during use will now be explained. This is followed by a further detailed description of the structure and operation of certain aspects of the device.

As explained above, the handle 10 of the electrosurgical instrument is arranged to i) clamp tissue between a set of jaws 14, ii) lock the jaws in place (if the user so desires), iii) deliver an RF signal to electrodes in the jaws 14 to coagulate the tissue clamped therebetween, and iv) move a cutting blade 340 between the jaws 14 to cut the tissue clamped therebetween. The handle 10 can also rotate the jaws 14 to allow the user to clamp tissue at different angles without having to rotate the entire handle 10. As a result, the tissue clamped between the jaws can be sealed using the same electrosurgical instrument before or during cutting. Furthermore, this effect can be achieved by the instrument with one-handed operation by the surgeon.

2.1 Clamping mechanism

To clamp tissue between the jaws 14, the user pushes the drive handle 22 toward the proximal end 328 of the housing 20 until the latching element 324 engages the latching molding 326 within the housing 20. This movement causes the drive handle 22 to pivot about its hinge 306, as shown in 8e -f, and pushes the edge of the handle collar ring 304 against the flange portion 800 to move the collar ring molding 310, the spring 312 and the inner molding 314 along the drive shaft 316 in the proximal direction, as shown in 4 and 5a As described above, the inner mold member 314 is secured to the drive shaft 316 by means of projections 602. Thus, when the inner mold member 314 is axially retracted, the drive shaft 316 is also axially moved, causing the pin 400 to move into the cam slot 402 of the jaws 14, thereby closing the jaws 14. Thus, the force from the drive handle 22 is transmitted to the drive shaft 316 via the spring mechanism of the collar ring mold member 310, spring 312 and inner mold member 314.

If tissue is clamped between the jaws 14, as in 5b As shown, the spring 312 acts to limit the force applied to the tissue. Once the axial movement of the collar ring molding 310, spring 312, and inner molding 314 is complete and the handle collar ring 304 continues to press against the flange portion 800, the threshold compression force of the spring 312 is eventually reached such that the spring 312 begins to compress between the collar ring molding 310 and the inner molding 314. As the spring 312 continues to compress, the drive handle 22 can be moved to the locked position without applying any further force to the clamped tissue. This means that the force of the drive handle 22 is no longer transmitted to the drive shaft 316, but is effectively absorbed by the spring 312. Thus, the spring 312 ensures that the correct amount of force is transmitted to the jaws 14. Without the spring 312, actuation of the drive handle 22 causes a continued increase in the force transmitted to the drive shaft 316 and subsequently to the jaws 14 and the tissue. This could cause mechanical damage to the tissue if the user continues to squeeze the drive handle 22 to engage the latch member 324.

As explained above, the cavities 608, 610 in the collar ring molding 310 and the inner molding 314 cooperate to enable the provision of a larger spring 312. This allows for a greater spring stroke so that the spring 312 is not compressed to its compression length during use. When the spring 312 reaches its compression length, it would no longer absorb the force exerted by the drive handle 22 and the force would be re-transmitted to the jaws 14.

2.2 Locking mechanism

When tissue is clamped between the jaws 14, the jaws 14 can be locked in a closed position by engaging the latching element 324 on the drive handle with the latching molding 326 inside the housing 20, as shown in 26a -f. As the latching element 324 enters the housing 20 through the opening 1102, the latching element 324 engages the latching molding 326, thereby pushing the molding 326 downward in the housing 20 and thereby pulling the spring 1104 apart. As shown in 26b -c, the detent member 324 moves upwardly along the side of the cam path 1106 until it reaches its maximum position. At this point, the drive handle 22 cannot be compressed any further and the spring 1104 pulls the detent molding 326 upwardly inside the housing 20 so that the detent member 324 is inserted into the V-shaped pocket of the cam path 1106 to hold the drive handle 22 in the compressed position and the jaws 14 in the closed position as shown in 26d shown.

In this locked position, the user's hand is free to operate the other functions of instrument 1, as explained below.

To release the latching element 324 from the housing 20 and open the jaws 14, the user must push the drive handle 22 toward the housing 20 to release the latching element 324 from the compartment of the cam path 1106, as shown in 26e The force of the spring 1104 pulls the latching molding 326 further up into the housing 20 so that the latching element 324 moves in the opposite direction down the side of the cam path 1106 as shown in 26e -f, and moved back out of the opening 1102. The latch molding 326 then returns to its original position inside the housing 20.

2.3 Cutting mechanism

When the jaws 14 are in a closed position, the user may wish to cut the tissue clamped between them. To cut the tissue, a cutting blade 340 is advanced between the jaws 14 by actuation of the drive assembly.

The drive assembly is a three pivot point arrangement that functions as a slide crank mechanism. When the user pulls the trigger 24 back towards the housing 20 as shown in 25b -c, the trigger molding 344 is levered about a pivot point A which is anchored to the housing 20, such as in the form of outwardly directed pins 358 which engage with corresponding moldings 356 which are integral with the shell moldings 300, 302 of 3 This causes the pivot point B connecting the trigger molding 344 and the drive molding 346 to be pushed past its central position, thereby translating the blade collar ring 348, the blade molding 352, and the cutting blade 340 along the drive shaft 316 with a force sufficient to allow the cutting blade 340 to cut the trapped tissue. In this regard, the force exerted on the trigger 24 is transmitted to the blade collar ring 348 and the blade molding 352 via the trigger molding 344 and the drive molding 346. As the pivot point B moves past the center point to its advanced position, the rate at which the blade collar ring 348 and the blade molding 352 are translated along the drive shaft 316 increases, thereby increasing the force acting on the cutting blade 340. This increases the force with which the cutting blade 340 cuts into the tissue without the user exerting additional force on the trigger 24.

The shaft molding 320 acts as a stop point for the blade collar ring 348 and the blade molding 352. Consequently, the pivot point B always remains above the other two pivot points A, C with respect to the drive shaft 316.

During actuation of the trigger 24, the force applied to the trigger 24 is sufficient to overcome the compression force of the tension spring 350 so that it extends along the same plane as the drive shaft 316 to permit axial movement of the blade collar ring 348 and the blade molding 352. Upon release of the trigger 24, the tension spring 350 is again compressed to retract the drive assembly to its original position. The tension of the tension spring 350 is sufficient to retract the cutting blade 340 through thick tissue without user intervention.

2.4 Shaft rotation

During use, the user may need to access tissue from different angles without having to move the entire instrument 1. For this reason, the jaws 14 are advantageously rotatable with respect to the handle 10 by means of the rotary wheel 28. This is particularly advantageous when the jaws 14 are on a curved path, such as the one shown in 16a -d. As explained above, the rotary wheel 28 is connected to the inner mold part 314 via interlocking elements 1200, 1202 so that the inner mold part 314 rotates with the rotary wheel 28. Since the end of the drive shaft 316 is connected to the inner mold part 314, the drive shaft 316 also rotates, which in turn also rotates the jaws 14 at their opposite end.

To allow this rotational movement without affecting the function of the clamping mechanism, the collar ring molding 310 is independently rotatable within the handle collar ring 304 so that the collar ring molding 310 also rotates with the drive shaft 316. Similarly, the blade molding 352 is independently rotatable within the blade collar ring 348 to allow rotation of the drive shaft 316 without affecting the function of the cutting mechanism.

To transmit the rotational movement to the outer shaft 12, the shaft molding 320 is rotatable in its socket 322. As described above, the shaft molding 320 acts as a rotational guide to control the rotational movement with respect to the drive shaft 316 along the entire length of the instrument 1. In addition, the active lines and return lines 1702, 1704 are arranged within the housing 20 to prevent damage to these lines 1702, 1704 by the rotating components. As described above, the lines 1702, 1704 are wound around the shaft molding 320 to allow the degree of rotation of the drive shaft 316. Consequently, the lines 1702, 1704 are unwound and rewound around the shaft molding 320 as it rotates.

2.5 Electrode activation

With the jaws 14 in a closed position, the user may wish to coagulate and seal the tissue clamped between them. To do so, the user initiates electrode activation using switch 26 on housing 20, which is conveniently located so that the user can easily access switch 26 while operating the device with one hand. This delivers an RF signal to the electrodes in the jaws 14 to coagulate and seal the tissue. The RF signal may be a pure or mixed waveform, depending on the desired effect.

After an overview of the structure and operation of the entire device, further detailed descriptions of the structure and operation of certain aspects of it follow.

3. Structure and operation of the clamping mechanism

As described above, the proximal handle 10 of the electrosurgical instrument 1 includes a first mechanism for actuating an aspect of a distal end effector assembly 14 such that the end effector assembly 14 changes between a first and a second position. The end effector assembly 14 may, for example, be a set of opposed jaws 14 arranged to be opened and closed. The mechanism used to initiate the movement of these jaws 14 is the so-called clamping mechanism which includes a drive handle 22 and two barrel-shaped collar ring moldings 310, 314 with a spring 312 compressed therebetween, all elements being lined up along an elongated drive shaft 316 extending between the jaws 14 and the handle 10 as shown in 4 and 5a -b is shown.

As from 8a As can be seen, the drive handle 22 includes a handle collar ring 304 in which the collar ring molding 310 is received. The handle collar ring 304 includes an opening 318 shaped like a keyhole or the number 8. The opening 318 consists of two adjacent openings 804, 806, wherein the upper opening 804 has a larger diameter than the lower opening 806.

The collar ring molding 310 is a cylindrical or barrel-shaped component having two flange portions 800, 802 spaced longitudinally apart. The diameter of the proximal flange portion 800 is larger than that of the upper and lower openings 804, 806. The diameter of the distal flange portion 802 is smaller than the upper opening 804 but larger than the lower opening 806.

During assembly, the collar ring molding 310 is first inserted through the upper opening 804, as shown in 8b -c. Since the distal flange portion 802 is smaller than the upper opening 804, it easily passes through it, while the proximal flange portion 800 is large enough to prevent the collar ring molding 310 from completely passing through the upper opening 804 is advanced. As can be seen 8d , the handle collar ring 304 is then pushed upward to engage the lower opening 806 with the collar ring molding 310.

After assembly, the collar ring molding 310 remains within the lower opening 806 of the handle collar ring 304 and is arranged such that its two flange sections 800, 802 are present on both sides of the handle collar ring 304, as shown in 8e . Since the lower opening 806 has a smaller diameter than both flange sections 800, 802, the collar ring molding 310 cannot be removed by simply pushing it through the lower opening 806. In contrast, the body of the collar ring molding 310 between the two flange sections 800, 802 has a slightly smaller diameter than the lower opening 806. Thus, the collar ring molding 310 is sufficiently loosely received in the lower opening 808 to permit rotational movement.

As from 8e As can be seen, the distance in the longitudinal direction between the two flange sections 800, 802 is only slightly larger than the thickness of the handle collar ring 304 so that the latter is precisely accommodated between the flange sections 800, 802. This ensures that the movement of the drive handle 22 is transmitted directly to the collar ring molding 310 and subsequently to the other components of the clamping mechanism. This is particularly important to ensure that the clamping jaws 14 respond to the movement of the drive handle 22 and that there is no delayed reaction between actuation of the drive handle 22 and the movement of the clamping jaws 14.

Once the collar ring molding 310 and the drive handle 22 are assembled, the remaining components can be assembled.

The drive shaft 316 is an elongated rod having one or more protruding members 602 disposed at its proximal end, as shown in 6 . The protruding elements 602 are flexible extensions that fan out from the surface of the drive shaft 316. This means that the protruding elements 602 are deformable such that they can be pressed flush against the surface of the drive shaft 316, but return to their original position when relieved of a counterforce. This allows the drive shaft 316 to be easily pushed through all of the components of the clamping mechanism during assembly, as described below.

The collar ring molding 310 has an internal cavity divided into two parts. The first part is a narrow channel or slot 607 for receiving the drive shaft 316, the distal end of the collar ring molding 310 including an opening 311 as shown in 3 which matches the T-shaped cross-section of the drive shaft 316. The diameter of the channel 607 is just slightly wider than that of the drive shaft 316 to provide a tight fit for better stability. When the drive shaft 316 is inserted, the protruding elements 602 are pressed flat to allow the drive shaft to be pushed completely through.

The second portion is a chamber 608 that is large enough to accommodate one end of the spring 312. The chamber 608 may extend over any suitable portion of the length of the collar ring molding 310. For example, the length of the chamber 608 may be about 25% of the length of the collar ring molding 310 up to 75% of the length of the collar ring molding 310.

The chamber 608 is substantially larger than the collar ring molding channel 607 so that as the drive shaft 316 is pushed through the collar ring molding 310, the protruding elements 602 extend outwardly back into their original structure when they reach the chamber 608.

The collar ring molding 310 and drive handle 22 assembly is slid along the drive shaft 316 until the collar ring molding 310 reaches a second set of protruding elements 600. These protruding elements 600 have a greater width than the opening 311 on the collar ring molding 310 to form an obstacle that prevents the collar ring molding 310 from moving further along the drive shaft 316. To this end, the protruding elements 600 must be sufficiently rigid so that the collar ring molding 310 cannot be pushed past the protruding elements 600 by applying force or pushing them inward.

The drive shaft 316 is then pushed through the center of the spring 312. The spring 312 preferably has a diameter just slightly larger than that of the drive shaft 312 so as to provide a closer fit between the spring 312 and the drive shaft 316. The spring 312 is then pushed along the drive shaft 316 until the end of the spring 312 fills the collar ring molding chamber 608.

The inner mold part 314 is a cylindrical or barrel-shaped component with an internal cavity divided into two sections. The first section is a chamber 610 in which a end of the spring 312 is received such that the spring 312 is partially enclosed by the collar ring molding 310 and the inner molding 314. The second portion is a narrow channel or slot 603 for receiving the proximal end of the drive shaft 316. The channel 603 is divided into two parts 604, 606. The first part of the channel 604 is shaped to allow the drive shaft 316 to pass therethrough while flattening the flexible extensions 602. To this end, the diameter of the first channel part 604 is only slightly larger than that of the drive shaft 316 to provide a tight fit. The tight fit of the drive shaft 316 in both the collar ring molding channel 607 and the inner molding channel 603 means that the drive shaft 316 is held firmly in place. This increases the stability of the drive shaft 316 in the housing 20, which is particularly important for ensuring maximum control of the end effector 14.

The second portion of the channel 606 provides a shoulder 605 into which the protruding elements 602 can extend. Consequently, when the drive shaft 316 passes through the channel 604 and into the second channel portion 606, the flattened protruding elements 602 fan out back to their original uncompressed position. After the protruding elements 602 have engaged the shoulder 605 of the second channel portion 606, the drive shaft 316 cannot be retracted through the first channel portion 604 and is thus retained within the inner mold portion 314. To accomplish this, the diameter of the second channel portion 606 must be sufficiently wide to allow the protruding elements 602 to extend beyond the diameter of the first channel portion 604. To accomplish this snap-fit connection, a protruding element 602 is only required on one side of the drive shaft 316.

This snap connection is designed such that any axial movement of the inner mold part 314 is transmitted to the drive shaft 316. In a similar manner, any rotational movement of the inner mold part 314, for example by the rotary wheel 28 formed around the inner mold part 314, is also transmitted to the drive shaft 316.

To complete assembly of the clamping mechanism, the drive shaft 316 is simply pushed through the collar ring molding 310, the spring 312 and finally the inner molding 314 until the protruding elements 602 snap into the second channel portion 606.

When positioned along the drive shaft 316, the collar ring molding 310, the spring 312, and the inner molding 314 are arranged such that the spring 312 is partially enclosed by the collar ring molding 310 and the inner molding 314. By providing the collar ring molding chamber 608 and the inner molding chamber 610 wherein a substantial portion of the spring 312 can be received, a longer spring 312 can be used without requiring additional space within the handle 10. The larger the collar ring molding chamber 608 and the inner molding chamber 610, the longer the spring 312. In addition, the spacing between the protruding members 600, 602 means that the ends of the spring 312 are compressed by the end walls 612, 614 of the collar ring molding chamber 608 and the inner molding chamber 610, respectively, so that the spring 312 undergoes an initial pre-compression during installation. This is important to ensure that the correct force is applied to the jaws 14 when the drive handle 22 is operated to activate the clamping mechanism.

In addition, the inner mold part 314 may be received in another barrel-shaped mold part, such as the rotary wheel 28, as in 13a -b. Here, the inner mold part 314 rotates with the rotary wheel 28, but is free to move axially in the inner cavity 1300 of the rotary wheel 28 between a first position, as in 13a shown, and a second position, as in 13b shown. Consequently, rotation of the wheel 28 rotates the inner mold member 314, which in turn rotates the drive shaft 316 and the jaws 14.

After all components are assembled, the drive handle 22 can be installed in the housing 20. For this purpose, the drive handle 22 is connected to the housing at its hinge 306. The hinge 306 can, for example, be two outwardly extending pins that mate with corresponding hinge moldings 308 that are integrally formed with the shell moldings 300, 302. This provides an anchor point about which the drive handle 22 can rotate.

Thus, the arrangement described above provides a mechanism for actuating the end effector assembly 14 that can be easily and safely assembled without any additional components.

In use, the user pushes the drive handle 22 toward the proximal end 328 of the housing 20, thereby rotating the drive handle 22 about its pivot 306. In doing so, the handle collar ring 304 pushes against the proximal flange portion 800, thereby moving the collar ring molding 310 in the longitudinal direction. This movement in Longitudinal displacement of the spring 312, the inner molding 314 and the drive shaft 316 back toward the proximal end of the handle 10, as shown in 5a As the drive shaft 316 is connected to the jaws 14, for example by a pin 400 and cam slot 402 arrangement, the jaws 14 are moved from the open to the closed position. The force from the drive handle 22 is transmitted to the drive shaft 316 via the spring mechanism of the collar ring molding 310, spring 312 and inner molding 314. This spring mechanism is particularly important because it acts to limit the force acting on any tissue clamped between the jaws 14.

When the drive handle 22 is depressed, the collar ring molding 310, the spring 312 and the inner molding 314 continue their axial movement until either the inner molding 314 reaches its most proximal position so that the jaws 14 are fully closed, as shown in 5a shown, or the clamping jaws 14 cannot be closed further due to tissue 500 trapped between them, as in 5b , in which case the drive handle 22 is not fully actuated so that it is held in place by the latching element 324. As the user continues to press the drive handle 22 and the handle collar ring 304 continues to abut the flange portion 800, the threshold compression force of the spring 312 is eventually reached so that the spring 312 begins to be compressed between the collar ring molding part 310 and the inner molding part 314 as shown in 5b can be recognized.

If the spring 312 is further compressed, the drive handle 22 can be moved to the latched position without exerting any further force on the clamped tissue 500. This means that the force of the drive handle 22 is no longer transmitted to the drive shaft 316, but is effectively absorbed by the spring 312. In this way, the spring 312 ensures that the correct amount of force is transmitted to the jaws 14. Without the spring 312, actuation of the drive handle 22 will continue to increase the force exerted on the drive shaft 316 and consequently on the jaws 14 and the tissue 500. This could result in mechanical damage to the tissue 500 as the user squeezes the drive handle 22 to engage the latching member 324.

For this reason, pre-compression of the spring 312 is important to ensure that the spring 312 absorbs the force of the handle 22 once the inner molding 314 reaches its final axial position. Similarly, a longer spring 312 allows for a greater spring stroke so that the spring 312 is not fully compressed to its block length during use. When the spring 312 reaches its block length, it would no longer absorb the force exerted by the drive handle 22 and the force would be re-transmitted to the jaws 14.

To hold the jaws 14 in their closed position, the latching element 324 on the drive handle 22 must be engaged with the latching molding 326 inside the proximal end 328 of the housing 20, as shown in 26a -f is shown.

11 shows that the latch molding 326 is a single, integrally molded component that includes a body portion 1108, a spring member 1104, and a cam path 1106. The proximal end 328 of the housing 20 has parallel walls 1100 that define a channel 1110 in which the body portion 1108 is received. The width of the channel 1110 is selected so that the body portion 1108 is retained in the channel 1110, but is still able to slide up and down the channel 1110 during use, as described below. To this end, the latch molding 326 is preferably made of a low friction material, such as polytetrafluoroethylene (PTFE), to allow the body portion 1108 to easily slide in the channel 1110 without sticking. For further stability in the channel 1110, a molded pin 330 may be provided in the housing 20 which engages a cam slot 331 provided on the body portion 1108, as shown in 46 shown.

The spring 1104 is placed at the end of the body portion 1108 and is arranged to bias the body portion 1108 upwardly within the channel 1110 toward the distal end of the housing 20. The spring 1104 may have any suitable configuration; for example, the spring 1104 may have a curved shape or a loop shape as shown in 11 . The cam path 1106 is a protruding molding molded onto the body portion 1108. The cam path 1106 includes a first cam surface 1112, a groove 1114, and a second cam surface 1116 to form a V-shaped molding.

The latch member 324 consists of an arm 1118 extending from the bottom of the drive handle 22. The arm 1118 has a pin 1120 disposed at its end and adapted to move along the cam path 1106.

In use, the latch member 324 is inserted into the housing 20 through an opening 1102. The pin 1120 engages the latch molding 326 so that the body portion 1108 is pulled downwardly within the channel 1110, thereby expanding the spring 1104. As shown in 26b -c, the pin 1120 moves along the side of the first cam surface 1112 until it reaches the top of the "V". At this point, the drive handle 22 cannot be depressed any further and the spring 1104 pulls the body portion 1108 back up in the channel 1110 so that the pin 1110 pushes into the groove 1114, thereby holding the drive handle 22 in the depressed position and holding the jaws 14 in the closed position as shown in 26d shown.

Thus, to engage the drive handle 22, the user need only activate the drive handle in the fully depressed position, wait until the pin 1110 engages the groove 1114, and then release the drive handle 22. In this engaged position, the user's hand is free to perform other functions of the instrument 1, such as operating the cutting mechanism using the trigger 24, rotating the jaws 14 using the rotary wheel 28, or operating the electrodes in the jaws 14 using the switch 26.

To release the locking element 324 from the housing 20 and open the clamping jaws 14, the user must push the drive handle 22 once more towards the housing 20. This releases the pin 1120 from the groove 1114, as shown in 26e As the pin 1120 exits the groove 1114, the force of the preloaded spring 1104 pulls the body portion 1108 back up in the channel 1110 so that the pin moves along the side of the second cam surface 1116 as shown in 26e -f. When the pin 1120 reaches the bottom of the second cam surface 1116, it pushes the body portion 1108 further up the channel 1110, allowing the pin 1120 to exit the opening 1102. The body portion 1108 can then return to its original position in the channel 1110.

To release the drive handle 22, the user simply needs to push the drive handle 22 toward the proximal end of the housing 20 and then allow the drive handle 22 to return to its original open position.

Furthermore, the latch molding 324 may include an override button 4600 integrally formed on the body portion 1108, as shown in 46 wherein the override button 4600 is engaged to change the position of the cam path 1106 such that the pin 1120 automatically exits the groove 1114 and releases the drive handle 22. Thus, if the latching mechanism were to fail for any reason, the user would be able to release the drive handle 22 to open the jaws 14.

The body portion 1108 may further be provided with an integral locking bar 4602 to allow the user to release the entire latching mechanism, the locking bar 4602 being movable between a first and a second position to manually slide the body portion 1108 within the channel 1110. When the locking bar 4602 is in the first position, the body portion 1108 is in its normal position so that the latching mechanism operates as above. The user may then move the locking bar 4602 to its second position, thereby moving the body portion 1108 upwardly within the channel 1110 so that the pin 1120 can only pass through the second cam surface 1116, thereby preventing it from engaging the groove 1114.

Such a latching mechanism is also suitable for many end effector assemblies. For example, such a latching element can be provided on the trigger 24 for the cutting mechanism to hold the cutting blade 340 in the activated position.

Upon release of the latch member 324, the drive handle 22 can be moved back to its original position. In doing so, the handle collar ring 304 releases the load exerted on the proximal flange portion 800 and presses against the distal flange portion 802, thereby pulling the collar ring molding 310 back to its original axial position. Consequently, the spring 312, the inner molding 314 and the drive shaft 316 are also axially retracted, which in turn returns the jaws 14 to the open configuration.

4. Arrangement and operation of the cutting mechanism

Various features and aspects relating to the structure and operation of the cutting mechanism will now be described. As described above, the proximal handle 10 of the electrosurgical instrument 1 includes a second mechanism for actuating another aspect of a distal end effector assembly 14. For example, the end effector assembly 14 may be a set of opposed jaws 14 and a cutting blade 340, with the distal end of the cutting blade 340 arranged to slide between the jaws 14 to cut tissue clamped between those jaws 14. The mechanism used to initiate movement of the cutting blade 340, which is disposed in a central track 342 of the drive shaft 316, is the so-called cutting mechanism. The cutting mechanism includes a drive arm 2000, a blade drive molding 346, a blade collar ring molding 348, a blade molding 352 and a tension spring 350, all of which are coupled together to form a 3-pivot point pusher crank mechanism as shown in 20a -b and 31 and 32 shown.

The drive arm 2000 is formed of a trigger 24 and the trigger molding 344, the trigger 24 being a finger gripping element for triggering the cutting mechanism and the trigger molding 344 being a handle collar ring 304 having a C-shaped side profile and an opening 364 through which the drive shaft 316 is inserted. The point at which the trigger 24 and the trigger molding 344 meet forms a pivot point A about which the drive arm 2000 is rotated. This first pivot point A is anchored to the housing 20, for example by means of outwardly facing pins 358 which are connected to corresponding moldings 356 which are integrally formed with the shell moldings 300, 302.

The distal end of the drive arm 2000, i.e., the end of the trigger molding 344, is pivotally connected to the blade drive molding 346 to form a second pivot point B. The blade drive molding 346 is an H-shaped frame with two parallel arms and a strut therebetween. Thus, the parallel arms of the blade drive molding 346 are pivotally connected to the trigger molding 344 at one end, for example, by means of outwardly facing pins 366 and mating connectors 368. At the opposite end, the parallel arms of the blade drive molding 346 are also pivotally connected to the blade collar ring molding 348 to form a third pivot point C, for example, by means of outwardly facing pins 372 and mating connectors 370.

As in 21 to 23 As shown, the blade collar ring molding 348 is a cylindrical or barrel-shaped component having a chamber 2104 in which the blade molding 352 sits, the blade molding 352 being a cylindrical or barrel-shaped component having a body 362 that fits into the chamber 2104 of the blade collar ring molding 348. The blade molding 352 further includes a flange 360 having a diameter larger than that of the chamber 2104 such that the flange 360 abuts against the distal lip edge 2200 of the blade collar ring molding 348, as shown in 22 As a result, the flange 360 ensures that the correct end of the blade molding 352 is inserted into the blade collar ring molding.

The body 362 is provided with a small groove 2202 around its periphery to provide a shoulder that engages the distal nose 2200 so that the blade molding 352 and the blade collar ring molding 348 are connected together via a snap fit. The distal lip edge 2200 mates with the groove 2202 to hold the blade molding 352 in the blade collar ring molding 348 while allowing the blade molding 352 to rotate freely in the chamber 2104. Thus, the blade molding 352 and the blade collar ring molding 348 are free to rotate concentrically.

Once the blade collar ring molding 348 and the blade molding 352 are assembled, the cutting blade 340 can be 24a -c. In this regard, the blade molding 352 includes a T-shaped opening 2300 extending along its length and shaped to receive both the cutting blade 340 and the drive shaft 316, as shown in 23 shown.

The proximal end of the cutting blade 340 includes an engagement element 2102 that extends further than the general profile of the remainder of the cutting blade 340, that is, it does not lie in the same axial plane. As in 24c As shown, the body 362 further includes a recess 2100 in which the engagement member 2102 is retained. To facilitate placement, the proximal end of the cutting blade 340 is cut at a first point opposite the engagement member 2102 to provide a beveled edge 2400 and is cut at a second point adjacent the engagement member 2102 to provide a recessed portion 2402. Thus, the proximal end of the cutting blade 340 has an L-shaped profile.

In order to arrange the cutting blade 340 in the arrangement of blade molding 352 and blade collar ring molding 348, the cutting blade 340 is aligned at an angle to the longitudinal axis of the instrument 1 opposite the T-shaped opening 2300 such that the engagement element 2102 and the beveled edge 2400 can be introduced into the inner cavity 2404 of the blade molding 352, as in 24a -b. Then, the cutting blade 340 is pulled downward in line with the longitudinal axis to press the engagement element 2102 into the recess 2100, as shown in 24c Thus, the engagement element 2102 is effectively hooked to the shoulder 2406 of the blade molding 352, whereby the proximal end of the cutting blade 340 is held in the inner cavity 2404.

The drive shaft 316 can then be inserted through the T-shaped opening 2300 with the cutting blade 340 received in the central track 342 as shown by 22 and 23 Thus, longitudinal movement of the assembly of blade collar ring molding 348 and blade molding 352 along drive shaft 316 translates cutting blade 340 along path 342.

To complete the blade trigger assembly, a tension spring 350 extends between the blade collar ring molding 348 and the drive arm 2000, for example by means of hooks 2002, 2004.

During use, the user pulls the trigger 24 back to the housing 20 as shown in 25b -c, so that the drive arm 2000 is pivoted about the first pivot point A. This forces the second pivot point B forward in the distal direction, causing the drive molding 346 to push the assembly of blade collar ring molding 348 and blade molding 352 along the drive shaft. The load exerted on the trigger 24 is therefore transmitted to the blade collar ring molding 348 and the blade molding 352 via the trigger molding 344 and the drive molding 346. Because the proximal end of the cutting blade 340 is retained in the blade molding 352 as described above, the cutting blade 340 slides along the central track 342 with the assembly of the blade collar ring molding 348 and the blade molding 352. Because the blade molding 352 is independently rotatable within the blade collar ring molding 348, the drive shaft 316 can be rotated without affecting the operation of the cutting mechanism.

The operation of the mechanism is optimized to provide a good force transmission at the beginning of the path of the cutting blade 340 when the user's finger is extended and less powerful, and also at the end of the path of the cutting blade 340 where more forces work against the path of the cutting blade 340, such as the force of the spring 350, friction within the track 342 and the force required to penetrate thick tissue. As can be seen from 27 As can be seen, a constant force is applied by the user to the trigger 24. The mechanism converts this trigger force into a high output force of the cutting blade 340, which decreases as the cutting blade 340 is displaced along the path 342 and increases again when the cutting blade 340 reaches the jaws 14. When the pivot point B moves from its retracted position to its advanced position, as shown in 28a -b such that β > 90°, the rate at which the blade collar ring 348 and the blade molding 352 are translated along the drive shaft 316 is therefore increased, thereby increasing the force of the cutting blade 340. Thus, the mechanism is able to advance the cutting blade 340 with sufficient force to effectively cut the tissue clamped between the jaws 14 without the user having to apply additional force to the trigger 24.

Further, the cutting mechanism may be required to slide the cutting blade 340 around a curved set of jaws 14, which increases the frictional forces opposing the sliding of the cutting blade 340. The frictional force is a product of the coefficient of friction of the cutting blade 340 within the web 342 and the force that the cutting blade 340 exerts on the walls of the web 342 as a result of the bending.

To reduce this frictional force, the lateral flexibility of the distal end of the cutting blade may be graded. Such graded flexibility may be achieved, for example, by preferably weakening the cutting blade 340 such that it is able to bend along the path 342 while remaining rigid in the direction of the cutting force. Preferably weakening may be achieved, for example, by providing one or more openings or one or more slots 354 in the distal end, as shown in 47a Such openings may be of constant or varying size or shape, depending on the degree of flexibility required. For example, in 47b Two adjacent openings 4702, 4704 of different sizes are provided, with the larger opening 4702 providing a higher degree of flexibility than the smaller opening 4704. As a further example, 47c three openings 4706, 4708, 4710 of varying size and shape are provided, with the largest opening 4706 being located most distally to provide increased flexibility in that region. Preferred weakening may further be achieved by graduating the thickness of the cutting blade 340 such that the distal end of the cutting blade 340 is beveled 4700 as shown in 47d shown.

Alternatively, patterned laser cuts 4712 or chemical etchings may be applied in the distal end to control the bending strength along a length of the cutting blade 340, as shown in 47e The distance between such cuts can be constant or increase gradually from the distal to the proximal end.

Preferably, the cutting blade 340 is divided into at least three regions of varying flexibility, for example, a distal region, a middle region, and a proximal region, with the distal region having greater lateral flexibility than the middle region, and the middle region having greater flexibility than the proximal region. For example, the distal region may be formed by a beveled end 4700 to provide the greatest degree of flexibility; the middle region may be formed with an opening 354 to provide a relatively lesser degree of flexibility; and the proximal region may be formed by a solid rod to provide even less flexibility, as in 47a In another, in 47b In the example shown, the distal region has a large opening 4702 to provide the greatest degree of flexibility; the middle region includes a smaller opening 4704 to provide reduced flexibility; and the proximal region is again a solid rod with the least degree of flexibility. The distal region, middle region, and proximal region may be obtained using any suitable combination of the preferred weakening described above.

Another way to reduce the frictional force due to the curved path is to apply a low friction coating to at least one side of the distal end of the cutting blade 340. For example, the cutting blade may be coated, for example using physical vapor deposition (PVD) or chemical vapor deposition (CVD) processes, with a low friction or non-stick material, such as a PTFE composite or other low friction polymer composite.

5. Drainage openings

Various other features and aspects relating to the structure of the drive shaft 316 will now be described. As described above, the drive shaft 316 is an elongated rod having a T-shaped cross-section as shown in 10a . The drive shaft 316 includes a slot or track 342 along its length adapted to receive another elongate member, such as the cutting blade 340 used in the cutting mechanism described above. In one application, the cutting blade 340 is caused to slide along the length of the drive shaft 316 to displace the distal end of the cutting blade 340 between the jaws 14 to cut tissue clamped therebetween.

Over time, blood and tissue can collect in the distal end of the instrument 1, particularly along the outer shaft 12 and the drive shaft 316. This accumulation of blood and tissue can cause the cutting blade 340 to stick in the drive shaft 316, reducing the functionality of the instrument 1, particularly the cutting mechanism. To prevent this, portions of the distal end of the drive shaft 316 are cut out to reduce the contact area between the drive shaft 316 and the cutting blade 340 and thus also the surface area on which blood and tissue can stick.

These cut-out sections can create openings such as those in 10b -c, such that the distal end of the drive shaft 316 includes a supporting base with forked side walls. The cut-out portions may also extend to the base of the drive shaft 316 such that the distal end includes forked side walls and an open bottom. To maximize the amount of drainage provided by these openings 1000, the openings preferably comprise more than 50% of the depth of the drive shaft 316.

Thus, these openings provide 1000 drainage openings between the central track 342 and the exterior of the drive shaft 316.

6. Rotary wheel and switch

Various other features and aspects relating to the operation of the adjustment wheel 28 (also referred to herein as the rotary wheel) will now be described. The adjustment wheel 28 is provided to allow the user to rotate the outer shaft 12 upon which the end effector assembly 14 is mounted. In order to reduce the space required and thus produce a more compact instrument, the internal volume 1300 of the adjustment wheel 28 is also used to provide a movement space for the inner molding 314 which forms part of the clamping mechanism described above. With such an arrangement, a more compact mechanism can be obtained.

In detail, the rotary wheel 28 (also referred to herein as an adjusting wheel) comprises a tooth-like plastic wheel having a plurality of notched portions 336 arranged around its outer diameter. The adjusting wheel 28 has the appearance of a gear wheel, with the notched cut-out portions arranged to ergonomically accommodate a user's thumb. In this regard, and as shown in 13a , 13b , especially in 14a , shown in more detail, the notched sections are at an angle when used to the plane of rotation of the adjustment wheel, so that in general the adjustment wheel or rotary wheel 28 has a slightly frusto-conical shape that is wider at an end remote from the user than at the end near the user. The notched portions 336 each extend from the distal edge of the adjustment wheel to the proximal edge and are curved or saddle-like in shape to accommodate a user's thumb during use. As detailed in 14a shown, the angular shape of the notched portions 336 to achieve the frustoconical shape of the rotary wheel 28 generally matches the angle of the body of the instrument. In 14a the dotted lines illustrate the angular shape of the notches 336 around the edge of the wheel 28, which can be viewed distally tangential to the angle of the outer walls of the instrument at the point around the wheel, and particularly the portion of the outer walls of the instrument immediately forward of the wheel. Such an arrangement, in which the angled notches of the outer edge of the rotary wheel match the angle of the wall of the instrument around the wheel, provides a comfortable and ergonomic shape that is easy to use by the surgeon.

With respect to the number of notched portions 336 around the outer diameter of the wheel 28, as shown in one embodiment, eight notched portions are evenly spaced around the outer diameter of the wheel. In other embodiments, a fewer or greater number of notched portions may be used, for example as few as six or seven, or as many as nine or ten. If a larger wheel 28 is to be used, a greater number of notched portions 336 may be provided, and conversely, if a smaller wheel is to be used, the number of portions may be fewer. In this regard, the actual size of each notched portion 336 should typically remain the same, as the notched portions are ergonomically selected to comfortably accommodate a user's thumb.

Regarding the positioning of the adjusting wheel 28 within the instrument, as shown in 2 As shown, the rotary or adjusting wheel 28 is positioned vertically aligned below the switch 26 and is spaced from the adjusting wheel in a direction orthogonal to a longitudinal axis, which is defined, for example, by the longitudinal direction of the drive shaft 316. In particular, the hand switch 26 lies directly on an axis orthogonal to this longitudinal axis which also passes through the adjusting wheel 28. Furthermore, as in 14a and 14b , the switch 26 is relatively large in size and extends across the control wheel from one side of the upper surface of the instrument to the other. The switch 26 is curved in nature to generally conform to the curved upper surface of the outer wall of the instrument and has ridges, grooves or other raised projections on its outer surface to assist the user in grasping the switch for depressing it with his or her thumb. The surface area of the switch 26 is relatively large, more than 3 ^cm2 or even 5 ^cm2 . This provides a large surface area to allow ergonomic activation thereof by the user. The vertical orientation of the switch 26 immediately above the control wheel 28 also allows ergonomic activation. As explained elsewhere, the switch 26, in use, serves to cause an RF coagulation signal to be delivered to the end effector for coagulating tissue therein.

Regarding the ergonomics of the switch and the adjustment wheel, 35a and 35b two corresponding representations of different users with different sized hands. As shown, since the switch 26 has a relatively large area, it is easy to operate by users with different sized hands while simultaneously operating the drive handle 22 (and the blade trigger 24 if desired).

Back to 12 As previously described, the adjusting wheel 28 has an internal cavity 1300 which, in use, is received within the inner molding 314. As previously described, the inner molding 314 includes an internal molding chamber 610 and has a T-shaped severed portion 1208 therein through which the drive shaft 316 is received and secured, as previously described. The inner molding 314 is snapped into the internal cavity of the wheel 28 and flanges 1206 are provided as in 12 as well as 29a and 29b shown, are provided around the outer edge of the cylindrical inner cavity 1300 of the adjusting wheel 28 to hold the inner mold part 314 in place within the cavity once it is inserted therein. The inner cavity 1300 of the adjusting wheel 28 is further provided with locking elements 1200 which interact with corresponding locking elements 1202 provided around the outer periphery of the inner cylindrical mold part 314. The respective locking elements 1200 and 1202 include corresponding raised step portions which fit side-by-side circumferentially around the inner surface of the cavity 1300 when the adjusting wheel 28 and the inner cylindrical mold part 314 are in the correct rotational alignment relative to one another. The respective locking elements 1200 and 1202 are provided such that, in use, the inner cylindrical mold part 314 can slide from side to side within the inner cavity of the wheel 28, but cannot rotate within the wheel 28. Instead, the interacting locking elements 1202 act and 1200 such that the inner mold member 314 rotates with the rotary wheel 28 when the latter is rotated. In this manner, any torque imparted to the rotary wheel 28 by the user 28 is transferred to the inner mold member 314 and then to the drive shaft 316 to rotate the drive shaft carrying the end effector. 29a and 29b show the inner mold part 314 inserted into the inner cavity of the adjusting wheel 28 and illustrate how the inner mold part 314 can slide axially within the inner cavity 1300 of the wheel 28.

13a and 13b further show in more detail how the inner mold part 314 is able to move within the inner cavity 1300 of the wheel 28. As described above, the drive shaft 316 passes through the T-shaped opening 1208 in the inner mold part 314 and is secured therein by means of protruding snap-lock or detent elements 602 provided on the end of the drive shaft. The detent or detent elements 602 are in the form of spring metal tabs which are also able to pass through the T-shaped opening 1208 in the inner mold part 314 and are then received in a second channel portion 606 of the inner mold part which forms a cavity which allows the spring tabs to spring apart, thereby securing the drive shaft within the inner mold part. The inner mold part 314 is then pushed into the inner cavity of the adjusting wheel 1208 and held in place by the locking projections 1206 as described above. The inner mold part can move axially within the inner cavity 1300 to come into engagement against the inner surface of the distal wall of the wheel 28 as shown in 13a shown, or, at its opposite end of extension, to come into abutment against the engaging elements 1206 on the distal edge of the wheel. Thus, the inner mold part 314 is provided with a degree of axial sliding movement within the cavity of the adjusting wheel 28 which is required as part of the mechanism to control the force exerted by the user on material contained within the jaws, as described above.

The locking feature of the inner molded part 314 in the inner cavity of the adjusting wheel 28 greatly improves the assembly of the device and makes the assembly of the device significantly easier and therefore cheaper. In order to position the adjusting wheel in the housing, as in 33 As shown, the outer distal wall 1310 of the adjustment wheel 28 is concentric with and flush with an inner support wall 1320 provided as a projection from the housing of the device. This also allows for easy and accurate assembly and positioning of the wheel 28 within the housing.

7. Rotation control of the drive shaft

As explained above, the outer shaft 12 with the end effector 14 thereon is rotatable to allow the end effector 14 to be moved to desired rotational positions for cutting and coagulating tissue. However, in order to prevent the cable connections to the end effector from being overstressed by rotating the shaft too far in one direction, causing the cabling to become coiled, twisted, or under excessive stress, a mechanism for controlling the rotation of the outer shaft 12 is required, particularly to limit the amount of rotation and thus prevent excessive stress on the cabling. In addition, positive control of the rotation of the outer shaft 12 improves the ergonomic experience of the instrument during use and the user's perception of quality.

To provide rotation control of the shaft, in one embodiment an arrangement is used which is 15a and 15b as well as 16a to 16d shown. With regard to 15 Here, the adjusting wheel 28 is provided with notched portions 36 on its proximal surface (i.e. rear surface facing the user) with a ring 1506 which projects slightly from the proximal surface which is concentric with the axis of the wheel 28. The ring 1506 rests in use on guide stop elements 1502 and 1504 which are projections on the inner surface of the outer housing which project to be able to contact the outer periphery of the ring 1506. Because of their positioning on the housing with respect to the axis of the ring, the stop part 1502 is smaller than the stop part 1504, but both stop parts 1502 and 1504 have angled upper guide surfaces 1510 and 1512 respectively (see 15a) which are in contact with the outer peripheral surface of the ring 1506 which forms part of the adjusting wheel, and help to support and guide the adjusting wheel during its rotation.

In addition to providing a guiding function, the stop members 1502 and 1504 also function as a stop member to prevent rotation of the adjusting wheel beyond the angular position of the stop members. In this regard, the ring 1506 is provided with a rectangular stop projection 1500 extending radially therefrom. When the adjusting wheel 28 is rotated, the stop projection 1500 comes into contact with corresponding stop surfaces 1514 and 1516 of the stop members 1502 and 1504. The stop surfaces ver run at an angle to be parallel to the rectangular stop projection 1500 when the stop position is positioned at an angle to abut against it.

The stop members 1502 and 1504 arranged as described above are positioned and of such length that they provide a known amount of rotation of the wheel 28 from the stop member 1500 to the stop member 1502. In the presently described and in 15a and 15b In the arrangement shown, the stop members 1502 and 1504 are positioned on the housing at a distance from one another to allow the adjustment wheel to rotate 270° from stop to stop. The amount of rotation can be easily varied by increasing or decreasing the distance between the stop members, with the stop members being adjusted accordingly in terms of the length and angle of the guide and stop surfaces to meet the wheel and stop members substantially perpendicularly, respectively. For example, the stop members can be positioned and shaped to provide an angular rotation of the wheel between 250° and 300°.

The above describes the rotation control applied to the adjustment wheel (and then, via the adjustment wheel, the shaft). 16a to 16d show another rotation control mechanism applied to the shaft at the opposite end of the shaft using the shaft molding 320. Here, the shaft molding is provided with a rectangular stop member 1600 extending therefrom. The inner surface of the outer housing is further provided with corresponding molded stop members 1602 and 1604 shown in the form of a member with steps providing corresponding stop surfaces that present corresponding parallel stop surfaces to the rectangular stop member 1600 at corresponding angular positions of the shaft molding 320. In the example shown, the molded stop members are positioned on the housing and present corresponding stop surfaces to the stop member 1600 to allow 270° rotation of the outer shaft 12 moving the end effector from stop to stop. In further embodiments, the molded stop portions 1602 and 1604 may be positioned to provide stop surfaces to the stop member 1600 at other rotational angular positions of the molded portion 320 to provide a greater or lesser degree of rotation, for example, from 180° to 360°, or more preferably from 250° to 300°, or most preferably 270°.

The respective rotation control mechanisms provided in the adjusting wheel 28 and in the shaft molding 320 may be provided independently of each other, i.e. they do not both have to be provided in a particular embodiment, but only one or the other may be provided to provide rotation control of the shaft. However, it is advantageous in terms of operation and quality perception of the device if both rotation control mechanisms are provided in one device and are aligned such that they provide stopping of rotation at the correspondingly same points in both directions of rotation. Such an arrangement means that the rotation of the shaft is stopped independently at both ends of the handle 10 and it becomes very difficult for a user to force further undesired rotation of the shaft beyond the permitted limits given by the stops.

An alternative rotation control mechanism is in 36 and 37 shown. 36 again shows the shaft molding 320, but here the molding is provided with a ring 3220 on which are mounted a primary rectangular stop element 3202 extending radially therefrom and secondary position marking elements 3204, 3206 and 3208 which are arranged substantially equiangularly around the ring, preferably in orthogonal positions. The secondary position marking elements 3204, 3206 and 3208 form small raised projections which are not large enough to engage the stop surfaces 3212 and 3214.

The stop surfaces 3212 and 3214 are provided as integral molded parts with the outer housing and are positioned here to allow rotation of the shaft molding 320 through 180°. In this regard, the stop element 320 comes into contact with the stop surfaces 3212 and 3214 at the ends of the rotation range to prevent further rotation of the shaft molding. Thus, as in 36a to 36c shown, the shaft molding 320 carrying the outer shaft 12 may rotate through 180° to allow rotational positioning of the end effector as desired.

Further provided is a resilient projection 3216 comprising a plastic projection of substantially triangular cross-section extending upwardly from the molding-forming stop surface 3214 such that its tip contacts an outer peripheral surface of the ring 3220. The secondary position markings in the form of small raised projections press against the tip of the resilient projection when the shaft molding 320 rotates, causing the tip of the resilient projection to move from its rest position to allow the corresponding projection to past the tip. The effect of this is to provide some user feedback as the user must apply more force to move the mechanism past the rotational positions where the raised projections contact the tip of the resilient projection as sufficient force must be provided to cause the tip of the resilient projection to flex in order for the projection to move past the tip. The result is that the user perceives an increase in the force required to rotate the shaft past the rotational positions of the raised projections and thus an indication of the rotational position of the shaft and hence of the end effector is provided to the user in an intuitive manner. Such a haptic feedback mechanism thus allows for user-friendly and simple operation of the device.

37 shows the corresponding setting wheel 28 for the mechanism in 36 Here, the adjustment wheel is also provided with respective small stops 3222 arranged orthogonally at 90° intervals around the adjustment wheel. A similar mechanism may be provided for the resilient projection 3216 extending from the housing to provide similar haptic feedback as in the case of the shaft molding 320. In such an arrangement, haptic feedback on the rotational position of the shaft is provided from both ends of the handle and thus the user's perception of the device is improved.

8. Wiring

At this point, further features and aspects relating to the wiring within the handle 10 will be described. As described above, the switch button 26 is provided to enable and disable the RF signal for operating the electrodes in the end effector assembly 14 via suitable circuitry, for example, via two intrusion-proof switches on a small printed circuit board (PCB) 338. As shown in 17 As shown, the PCB 338 is connected to a connection line 1700 for receiving the RF output from a generator (not shown) and electrical wiring 1702, 1704 for providing the RF current to the electrodes in the jaws 14, for example, one cable for the active electrode and one for the counter electrode.

In the arrangement, the wiring 1702, 1704 is routed from the electrodes down the outer shaft 12, along the drive shaft 316 and up to the shaft molding 320, as shown by 17 As shown in 9b , the shaft molding 320 is a cylindrical or barrel-shaped component having an opening 912 at the distal end to receive the outer shaft 12. The outer shaft 12 is secured to the shaft molding 320, for example, by detent projections 900 that cooperate with corresponding grooves 902 in the shaft molding 320. Consequently, when the shaft molding 320 rotates, the outer shaft 12 rotates with it. The shaft molding 320 further includes another opening 914 at the proximal end, the opening 914 having a T-shape to receive the drive shaft 316, the drive shaft 316 extending through the interior cavity 1802 of the shaft molding 320 and down the length of the outer shaft 12. Thus, the drive shaft 316 is able to slide within the shaft molding 320 and the outer shaft 12, but any rotational movement of the drive shaft 316 is transmitted to the shaft molding 320 and subsequently the outer shaft 12.

As in 18a As shown, the electrode cables 1702, 1704 are led from the interior cavity 1802 through an opening 1800 in the wall of the shaft molding 320 before being wrapped over and around the body 1804 of the shaft molding 320. Wrapping the cables 1702, 1704 around the shaft molding 320 in this manner keeps the cables 1702, 1704 in a compact arrangement to prevent the cables 1702, 1704 from interfering with the assembly of the remainder of the instrument 1. Furthermore, winding the cables 1702, 1704 around the shaft molding 320 means that when the shaft molding 320 rotates with the drive shaft 316, the cables 1702, 1704 unwind and rewind with the rotation without the cables 1702, 1704 being overstretched and thereby short-circuited. In particular, winding the cables 1702, 1704 in this particular manner allows up to 270° of rotation, as described with respect to 15ab and 16a -d described.

The electrical wiring 1702, 1704 is then routed along the top of the housing 20. In this regard, one of the tray moldings 300 is provided with two compartments 1900, 1902 arranged side by side to receive the cable contacts 1904, 1906 that connect the active and return cables 1702, 1704 to the wiring 1908, 1910 of the ingress protection switches 338. All of the electrical cables 1702, 1704, 1908, 1910 are routed into and around the compartments 1900, 1902 so that only one contact 1904, 1096 is received in each compartment 1900, 1902. The routing of the cables can be facilitated by guide sections 1912, 1914, 1916 which guide a set of the cables 1702, 1910 around the exterior of the compartments 1900, 1902.

In each compartment, the respective active cable 1702 is connected to the cable 1908 in the longitudinal direction and the return cable 1704 is aligned with the cable 1910 in the longitudinal direction.

Consequently, the two cable contacts 1904, 1906 are separated longitudinally so that only one contact can pass through each compartment 1900, 1902, thereby providing a physical barrier between each contact 1904, 1906 and the wiring. This eliminates the risk of damage to the insulation of one of the cables by the contacts 1904, 1906 themselves.

The cables 1702, 1704, 1908, 1910 are all inserted into their respective compartments 1900, 1902 via small openings 1918, 1920, 1922, 1924 in the walls of the compartments. Preferably, the dimensions of the openings 1918, 1920, 1922, 1924 are such that only one electrical cable can pass through. The opposing shell molding 302 also includes corresponding rib members (not shown) to retain the contacts 1904, 1906 in the compartments 1900, 1902 to form a substantially sealed housing. This is important to minimize the permeability of the compartments 1900, 1902 to protect the contacts 1904, 1906 from any fluid that might leak along the outer shaft 12 and into the housing 20, causing shorting of the contacts 1904, 1906.

9. End effector arrangements

Exemplary end effector arrangements that may be used with the device will now be described. The examples to be described are mentioned only for the sake of completeness, and it will be understood that other end effector designs may be used with the instrument so long as they are capable of being driven by the drive shaft 316. That is, embodiments of the invention are not limited to the specific end effectors described herein, but other end effector designs may be used as well.

38 to 44 show exemplary instruments in which electrically conductive stop elements are arranged on one or both of the sealing electrodes. With regard to 38 an end effector, generally indicated at 3801, includes an upper jaw 3802 pivotally connected to a lower jaw 3803 about a pivot point 3804. Flanges 3805 are provided at the proximal end of the upper jaw 3802, while flanges 3806 are provided at the proximal end of the lower jaw 3803. The flanges 3805 and 3806 each have slots 3807 through which a drive pin 3808 extends such that proximal and distal movement of the drive pin 3808 (via a drive mechanism (not shown)) causes the jaws 3802, 3803 to pivot between an open and a closed position.

A metallic clamp 3809 is provided on the inner surface of the upper jaw 3802, while a metallic clamp 3810 is provided on the inner surface of the lower jaw 3803. When the jaws 3802, 3803 pivot to their closed position, the metallic clamps 3809, 3810 come closely together to grasp tissue (not shown) between each other.

The upper clamp 3809 has a generally planar surface, except for an elongated recess (in 38 not visible) running along its length. The lower clamping piece 3810 has a corresponding recess 3811, the recesses in the clamping pieces 3809, 3810 accommodating the longitudinal movement of a cutting blade (not shown). The lower clamping piece 3810 is further provided with a plurality of metallic stop elements 3812 arranged along the length of the clamping piece and on both sides of the recess 3811. The stop elements 3812 will now be described with reference to 39 and 40 be described in more detail.

Each metallic stop element 3812 consists of the upper protrusion of a stop element 3813 received in an insulating element 3814 so as to enclose the stop element isolating it from the remainder of the clamping piece 3810. Each insulating element 3814 and stop element 3813 is disposed in a corresponding opening 3851 provided in the clamping piece 3810 so that the upper portion of the insulating element forms an insulating ring 3816 around each stop element 3812.

When the jaws 3802, 3803 are moved to their closed position (as in 40 shown), the stop elements 3812 contact the upper clamping piece 3809, maintaining a distance between the upper and lower clamping pieces of between 20 µm and about 350 µm (0.00079 inches to about 0.014 inches). In use, an electrosurgical coagulation voltage is applied between the clamping pieces 3809, 3810, and the distance between the clamping pieces ensures effective sealing of tissue grasped between the jaws 3802, 3803. At the same time, electrical shorting between the clamping pieces is prevented because the stop elements 3812 are electrically isolated so that they do not have the same electrical potential as the rest of the clamp 3810. The metallic stop members 3812 are rigid, allowing consistent separation of the surfaces of the clamps, while it is feasible for the electrical potential of the stop members 3813 to be monitored to detect when they contact the upper clamp 3809 to indicate closure of the jaws.

41 to 43 show an alternative arrangement in which the metallic stop elements 3812 are mounted directly on the lower clamp 3810, without the insulating elements surrounding the stop elements. In this arrangement, insulating elements 3817 are provided on the upper clamp 3809 in corresponding relation to each of the stop elements. In this manner, when the jaws 3802, 3803 are closed, the insulating elements 3817 ensure that there is no electrical shorting between the upper clamp 3809 and the lower clamp 3810. The metallic stop elements 3812 ensure that the appropriate separation of the jaws is maintained during the application of electrosurgical energy to seal tissue grasped between the jaws.

44 shows finally a further alternative in which the metallic stop elements 3812 are again mounted directly on the lower clamping piece 3810. In this arrangement a metallic counterholder 3818 is arranged opposite each stop element, each metallic counterholder 3818 being surrounded by an insulating element 3819 in order to be insulated from the rest of the upper clamping piece 3809. When the clamping jaws are closed, there is metal-to-metal contact between the stop elements 3812 and the metallic counterholders 3818, the insulation of the counterholders ensuring that electrical short-circuiting between the clamping pieces 3809, 3810 is again prevented. Again, the electrical potential of each of the metallic counterholders can be monitored to detect when they assume the potential of the lower clamping piece, which indicates the closing of the clamping jaws.

10. Electrosurgical system

With reference to 45 It is contemplated that the instrument 1 will be connected, in use, to an electrosurgical generator 4500 having a controllable radio frequency (RF) source therein (not shown) which, in use, generates an RF coagulation signal which coagulates or seals tissue when applied thereto via the electrodes of the end effector of the instrument 1. The electrosurgical generator 4500 includes control input switches 4504 and 4502 to allow the generator to be turned on and off, respectively, and to allow controlling the power of the RF coagulation signal applied to the instrument 1. In this respect, the electrosurgical generator 4500 is conventional.

The instrument 1 is connected in use to the generator 4500 by a control and power supply line 4506 which includes separate electrical lines to allow delivery of an RF signal to the end effector of the instrument 1 via the internal wiring described above, and further to allow receipt of a control signal from the switch 26 of the instrument 1 to cause the electrosurgical generator to output an RF coagulation signal to the instrument 1. In use, the surgeon activates the generator via an on-off switch 4504 and selects the coagulation or sealing signal strength to be generated by the internal RF source using knobs 4502. During a surgical procedure with the instrument, when a sealing or coagulation RF signal is required at the end effector, the surgeon controls the generator to generate such a signal by depressing the switch 26 of the instrument, then the generated RF signal is passed to the end effector via the electrical leads 4506. That is, depressing the switch 26 during use causes the delivery of an RF coagulation or sealing signal to the appropriate electrodes contained in the end effector.

11. Summary

Therefore, in view of the above, embodiments of the invention provide an advanced electrosurgical forceps instrument that allows for easy and ergonomic one-handed operation by the user, provides rotational flexibility of the end effector, controls the force applied by the end effector to the grasped tissue to prevent application of excessive force, and allows for convenient mechanical cutting of the grasped tissue while simultaneously providing electrosurgical coagulation or sealing of the tissue. In addition, the instrument has been devised to be easily and inexpensively assembled while providing a compact instrument thanks to efficient use of the available space in the respective internal activation mechanism.

Various further modifications of the embodiments described above, whether by Addition, elimination, or substitution will be apparent to those skilled in the art to provide additional embodiments, each and every one of which is within the scope of the appended claims.

Claims (8)

Surgical instrument (1) comprising a handle (10) and a pair of curved first and curved second jaws (3802, 3803), one or both of the curved jaws (3802, 3803) comprising a curved slot (3811) to form a curved path therebetween, a blade assembly (340) arranged for longitudinal movement into a deployed state within the curved path, the blade assembly (340) comprising a cutting blade (340) at its distal end, a trigger mechanism arranged on the handle (10) and movable between a first position and a second position, moving the trigger mechanism from its first position to its second position causes longitudinal movement of the blade assembly (340) into its deployed position, characterized in that the blade assembly (340) has at least three adjacent regions, the first distal region has a first longitudinally extending slot (4702; 4706) and the second central region has a second longitudinally extending slot (4704; 4708) which is shorter than and flush with the first longitudinally extending slot (4702; 4706), whereby the first distal region has greater lateral flexibility, ie greater lateral bending, than the second central region, and wherein the second central region has greater lateral flexibility than the third proximal region. Surgical instrument (1) according to claim 1 wherein the blade assembly (340) is in the form of a rod (340) having a thickness substantially less than either its width or its length. Surgical instrument (1) according to claim 1 wherein the first slot (4702; 4706) in the first region and the second slot (4704; 4708) in the second region are adjacent to each other. Surgical instrument (1) according to one of the preceding claims, wherein the thickness of the blade assembly in the first region is less compared to its thickness in the second region. Surgical instrument (1) according to one of the preceding claims, wherein at least a portion of the blade assembly (340) is coated with a low-friction coating. A surgical instrument (1) according to any preceding claim, wherein a first region is disposed distally of the second region such that the second region lies at least partially within the curved path formed by the jaws (3802, 3803) when the blade assembly (340) is in its deployed position. A surgical instrument (1) according to any preceding claim, wherein the handle (10) further comprises an actuating mechanism movable between a first position and a second position, wherein moving the actuating mechanism from its first position to its second position causes at least one of the curved jaws (3802, 3803) to move relative to the other from a first open position in which the jaws (3802, 3803) are arranged in a spaced relationship relative to one another, to a second closed position in which the curved jaws (3802, 3803) cooperate to grasp tissue therebetween. A surgical instrument (1) according to any preceding claim, wherein the first longitudinally extending slot (4702) and the second longitudinally extending slot (4704) form a single longitudinally extending slot.

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