Laparoscopic bipolar electrosurgical instrument

ES 2 317 360 T3

DESCRIPTION

Bipolar laparoscopic electrosurgical instrument.

Background

Field of the invention

This description refers to a surgical instrument for performing laparoscopic surgical procedures and, more particularly, to a laparoscopic electrosurgical instrument that is capable of grasping blood vessels and vascular tissue with sufficient force between two bipolar jaws, in order to plug the blood vessel or vascular tissue.

Background of Related Art

Laparoscopic surgical instruments are used to perform a surgical operation without making large incisions in the patient. Laparoscopic instruments are inserted into the patient through a cannula, or port, that has been made with a trocar. Typical cannula sizes are in the range of three millimeters to twelve millimeters. Smaller cannulas are generally preferred, and this poses a design challenge for instrument manufacturers, who have to find ways to make surgical instruments that will fit through the cannulas.

Certain surgical procedures require cutting of blood vessels or vascular tissue. This sometimes poses a problem for surgeons, as it is difficult to suture blood vessels with the use of laparoscopic tools. Very small blood vessels, in the range below two millimeters in diameter, can often be closed with the use of conventional electrosurgical techniques. If a larger vessel is transected, it may be necessary for the surgeon to convert the laparoscopic procedure to an open surgical procedure and consequently forego the benefits of laparoscopy.

Certain articles in various publications have been describing methods to seal small blood vessels through the use of electrosurgery. An article entitled "Studies on Coagulation and the Development of an Automatic Computerized Bipolar Coagulator", J. Neurosurg., Volume 75, July 1991, describes a bipolar coagulator. used to block small blood vessels. The article states that it was not possible to safely coagulate arteries with a diameter greater than between 2 and 2.5 mm. A second article is entitled "Automatically Controlled Bipolar Electrocoagulation -" COA-COMP "" ", Neurosurg. Rev. (1984), pp. 187-190. This article describes a method of supplying electrosurgical power to the vessel through a terminal in such a way that scorching of the vessel walls can be avoided.

It has recently been determined that electrosurgical methods may be able to seal large vessels by using a suitable electrosurgical power curve, in combination with an instrument that is capable of applying a large closing force on the walls. of the glass. The small vessel coagulation procedure is thought to be fundamentally different from electrosurgical vessel filling. Coagulation is defined as a tissue desiccation procedure in which tissue cells are disrupted and dried. Vessel clogging is defined as the process of liquefying the collagen contained in the tissue in such a way that it forms cross-links and assumes a new melt shape. In this way, the coagulation of the small vessels is sufficient to permanently close them. Larger vessels need to be sealed to ensure permanent closure.

It would be desirable to have a surgical tool that is capable of applying electrosurgical energy, capable of applying a large closing force to the vessel walls, and also capable of fitting through a cannula. A large clamping force between the jaws typically requires a high pivot moment for each jaw. This poses a challenge because the first and second pins have a small moment arm relative to the pivot of each jaw. A large force in combination with a small moment arm is undesirable, because high forces can shear the first and second pins. It is also undesirable to increase the moment arm of the first and second pins, because the physical size of the yoke may not fit through a cannula.

Various bipolar laparoscopic instruments are known. For example, US Patent No. 3,938,527 describes a bipolar laparoscopic instrument for cauterizing the fallopian tube. US Patent No. 5,250,047 describes a bipolar laparoscopic instrument having a replaceable electrode tip assembly. US Patent No. 5,445,638 describes a bipolar cutting and coagulation forceps having first and second leads extending from the distal or further end. US Patent No. 5,391,166 describes a bipolar endoscopic instrument having a detachable or detachable working end. US Patent No. 5,342,359 describes a bipolar coagulation device.

The present invention solves the problem of providing a high closing force between the jaws of a laparoscopic bipolar electrosurgical instrument, using a compact design that fits through a cannula, without the risk of structural failure of the yoke of the instrument.

ES 2 317 360 T3

Summary of the invention

The present invention relates to a laparoscopic bipolar electrosurgical instrument intended for sealing tissue and including a handle having an elongated tube attached thereto. The tube includes first and second jaw members, attached to a distal end, or further away, thereof, which are capable of being displaced from a first position, to bring tissue closer to at least one subsequent position, in order to grasp or grab the tissue between them. Each of the jaw members includes an electrically conductive sealing surface. The handle has a fixed handle and a handle that is movable with respect to the fixed handle in order to carry out movement of the jaw members from the first position to the at least one subsequent position, in order to grasp the tissue. The jaw members are connected to an electrosurgical power source, such that the jaw members are capable of conducting bipolar electrosurgical energy through tissue clamped therebetween. A stop has been included to maintain a minimum separation distance between opposing sealing surfaces of at least about 0.03 millimeters, and a trigger or pawl has been included to maintain a closing force in the range of about 3 kg / cm² and about 16 kg / cm², between the opposing sealing surfaces. As can be appreciated, the abutment member advantageously creates minimal spacing between opposing electrically conductive sealing surfaces in order to achieve efficient, consistent and uniform tissue sealing.

Advantageously, the stop maintains a minimum gap distance of between about 0.03mm and about 0.16mm. The stop may be disposed on at least one of the electrically conductive sealing surfaces, or, alternatively, the stop may be located adjacent to one of the electrically conductive sealing surfaces. While it is preferable to position the stop member on one or both of the opposing electrically conductive sealing surfaces, in some cases it may be advantageous to position the stop member adjacent to the opposing sealing surfaces.

In one embodiment in accordance with the present description, the first jaw member is attached to the bipolar electrosurgical power source by means of a push rod, and the second jaw member is attached to the bipolar electrosurgical source by middle of a conductive tube. As can be appreciated, isolating the jaw means in this manner reduces the likelihood of the instrument shorting out during activation.

In another embodiment, the pawl has been disposed within the fixed handle, and a complementary mechanical interlocking interface is disposed on the movable handle. Preferably, the ratchet and the complementary interlocking mechanical interface provide at least one interlocking position to maintain a closing force in the range of about 7 kg / cm.² and about 13 kg / cm², between the opposing sealing surfaces. Ideally, the closing force is in the range of about 4 kg / cm²and about 6.5 kg / cm². As can be appreciated and as already mentioned here, maintaining the closing force within the above working ranges is a key factor in producing an efficient and consistent seal.

In yet another embodiment in accordance with the present disclosure, the laparoscopic bipolar electrosurgical instrument includes a handle having, attached thereto, an elongated tube with first and second jaw members attached to a distal end thereof, in such a way that each of them includes electrically conductive sealing surfaces. The jaw members may be movable from a first position, to approximate the tissue, to at least one subsequent position, to grip the tissue between them. The handle has a fixed handle and a handle that is movable relative to the fixed handle to effect movement of the jaw members from the first position to the at least one subsequent position for grasping tissue. Advantageously, the sealing surfaces may include a non-adherent material to reduce adhesion of the tissue during the sealing procedure. The first and second jaw members may be connected to a bipolar electrosurgical power source, and an abutment may be provided on at least one of the electrically conductive sealing surfaces, in order to maintain a minimum separation distance between the gaps. sealing surfaces capable of opposing, during sealing.

A trigger or ratchet is provided on one of the fixed and movable handles, and it is possible to provide at least one complementary mechanical interlocking interface on the other of the fixed and movable handles. Advantageously, the ratchet and the complementary interlocking mechanical interface include at least one interlocking position that maintains a closing force in the range of about 7 kg / cm² and about 13 kg / cm², between the sealing surfaces susceptible to opposing.

In one embodiment, the non-stick material is a coating that is deposited on the opposing sealing surfaces. As can be seen, this reduces the likelihood of clot accumulation and adherence. The non-adherent coating can be selected from a group of materials consisting of: nitrides and nickel / chromium alloys. Preferably, the non-adherent coating includes one of: TiN, ZrN, TiAlN, CrN, nickel / chromium alloys with a Ni / Cr ratio of about 5: 1, Inconel 600, Ni200 and Ni201.

In one embodiment according to the present disclosure, the opposing sealing surfaces are manufactured from a non-stick material consisting of a nickel / chromium alloy. For example, the non-stick material may include nickel / chromium alloys with a Ni / Cr ratio of about 3

ES 2 317 360 T3 given 5: 1, Inconel 600, Ni200 and Ni201. These particular materials are anticipated to be advantageous in providing a superior non-stick surface that reduces clot build-up and stickiness during activation.

Preferably, at least one of the jaw members, the handles and the elongated tube includes an insulating material arranged therein, which may advantageously be an insulating coating or an insulating sheath.

Brief description of the drawings

Figure 1 is a perspective view of a laparoscopic bipolar electrosurgical instrument in accordance with the present disclosure;

Figure 2 is a perspective view of the distal end, or further away, and of the jaws of the instrument of Figure 1;

Figure 3 is a fragmentary or exploded view of the distal end shown in Figure 1;

Figure 4 is a perspective view of the distal end of the instrument, with the jaws removed;

Figure 5 is another perspective of Figure 4;

Figure 6 is a side view of a spring electrical contact; and Figure 7 is a front view of the spring contact shown in Figure 6.

Detailed description of the invention

A laparoscopic bipolar electrosurgical instrument 10 is shown in Figure 1. Instrument 10 has a proximal, or closer end, 11 which has a handle 14 for holding and manipulating instrument 10. A distal, or further end, 12 of instrument 10 surgical manipulation of tissue is utilized. The instrument 10 comprises an elongated tube 13 that is dimensioned such that it will fit through a cannula for laparoscopic operations, and, in different embodiments, it can be dimensioned such that it will fit through cannulas of between five and ten millimeters.

Shown in Figure 2 is a portion of the distal end 12 of instrument 10. A first jaw 15 and a second jaw 16 are shown in an open position. An angle α is subtended between the jaws 15 and 16. The closing of the jaws 15 and 16 is defined as a reduction of the angle α subtended by the jaws 15 and 16. Similarly, the opening of the jaws 15 and 16 is defined as an increase in angle α. The angle α is zero when the jaws 15 and 16 are closed next to each other. The center of rotation for the first jaw 15 is at the first pivot 41, and the center of rotation for the second jaw 16 is at the second pivot 42. The first pivot 41 is located on an outer nose piece 32 , and fits into a first pivot hole 43, located in the first flange 18. The second pivot 42 is located in an inner nose piece 31, and fits into a second pivot hole 44 located in the second flange 20.

The parts comprising the distal end 12 of the instrument 10 are shown in an exploded view illustrated in Figure 3. The first jaw 15 and the second jaw 16 are shown separated from a yoke 17. The first jaw 15 has a first flange 18 and a first slot 19 located inside it. The second jaw 16 has a second flange 20 and a second groove 21 located therein. Each of the jaws 15 and 16 is preferably formed from a single piece of stainless steel or other electrically conductive material.

Referring again to Figure 3, the yoke 17 is attached to a push rod 22. The yoke 17 is preferably formed from an electrically insulating material, such as plastic. A first face 23 of the yoke 17 faces the first flange 18. A second face 24 of the yoke 17 faces the second flange 20. When yoke 17 is positioned between flanges 18 and 20, yoke 17 also acts to electrically isolate first jaw 15 from second jaw 16. In this way, bipolar electrosurgical current can be conducted through the grasped tissue. jaws 15 and 16, without causing any short circuit between flanges 18 and 20.

A first pin 25 is located on the first face 23 such that it movably engages with the first slot 19. Similarly, a second pin 26 is located on the second face 24 to releasably engage. to the second slot 21. Each pin and slot combination works as a cam follower mechanical link. The movement of the push rod 22 displaces the yoke 17 causing the pins 25 and 26 to slide into their respective slots 19 and 21. The slots 19 and 21 are arranged at an angle with respect to the distal ends of the jaws. 15 and 16, in such a way that the jaws 15 and 16 move arcuately towards each other and away from each other. Pins 25 and 26 are different from pins 41 and 42. The pins 25 and 26 provide a certain force against the walls of the grooves 19 and 21, creating a movement around the pins 41 and 42.

ES 2 317 360 T3

The grooves 19 and 21 are arranged such that the distal movement of the push bar 22 causes the jaws 15 and 16 to move together. The distal movement of the push rod 22 is defined as the movement in the direction towards the distal end 12 of the instrument 10. Once the jaws 15 and 16 have closed with each other, the instrument of the present invention holds the jaws 15 and 16 together as a certain compressive force is exerted on the push bar 22.

One of the advantages of this invention is that it is possible to relieve the shear or shear forces that are exerted on the pins 25 and 26 in order to avoid mechanical failure when large forces are being transmitted to the jaws 15 and 16. Each slot 19 and 20 have a cul-de-sac or blind bottom, 27 and 28 respectively, as shown in Figure 3. The first blind bottom 27 is an enlargement of the first slot 19 near its distal end. The second blind bottom 28 consists of an enlargement of the second slot 21 near its distal end. The cam follower movement of pins 25 and 26 within slots 19 and 21 will bring pins 25 and 26 into their respective blind bottoms 27 and 28. This position of pins 25 and 26 leaves a very small moment arm. between pins 25 and 26 and pins 41 and 42. Yoke 17 has shoulders 29 and 30 that can provide a relatively large moment about pivots 41 and 42 in order to exert a high closing force between jaws 15 and 16 without producing a large shear force on the jaws. pins 25 and 26, as described below.

Once the pins 25 and 26 are in the blind bottoms 27 and 28, the force originating in the yoke is transmitted to the flanges 18 and 20 by means of a first shoulder 29 and a second shoulder 30. The shoulders 29 and 30 abut the proximal end of flanges 18 and 20 in order to cause jaws 15 and 16 to close into one another. The pins 41 and 42 are preferably made of metal and can withstand relatively high shear forces. In contrast, the pins 25 and 26 are preferably made of plastic and will break under relatively high shear forces. In this way, shoulders 29 and 30 provide a certain moment around pivots 41 and 42, thus avoiding the need to apply high shear forces on pins 25 and 26, such that the moment arm originated at spikes 25 and 26 will be small. There is a certain angle α for which the pins 25 and 26 enter their respective blind bottoms 27 and 28, and the shoulders 29 and 30 butt contact the flanges 18 and 20. The angle α for which the above occurs is it is preferably around three degrees.

The bipolar electrosurgical instrument 10 has first and second poles of alternating potential that are conducted along the instrument 10 and through the tissue that is gripped between the jaws 15 and 16. The first pole is conducted from the proximal end 11 toward distal end 12 along push rod 22. The second pole is driven from proximal end 11 toward distal end 12 along tube 13. The outer surface of the tube 13 is preferably coated with an electrically insulating material. There is also, preferably, an electrically insulating barrier between the push rod 22 and the tube 13 in order to prevent short circuits in the instrument 10.

In the preferred embodiment, the distal end of instrument 10 comprises an inner nose piece 31 and an outer nose piece 32, as shown in Figure 2. The inner nose piece 31 is electrically connected to the push rod. 22, while the outer nose piece is electrically connected to the tube 13. The inner nose piece 31 and the outer nose piece 32 capture or trap the yoke 17, together with the first and second flanges 18 and 20, as shown in Figure 2. The yoke 17 moves axially, along of an axis defined by the tube 13, in a space located between the inner and outer nose pieces 31 and 32. A spacer post 33 maintains the separation of the nose pieces 31 and 32 at their distal ends. Nose pieces 31 and 32 provide lateral support for flanges 18 and 20 to help ensure that pins 25 and 26 remain within slots 19 and 21, respectively.

The preferred embodiment also comprises an internal insulating element 34 and an external insulating element 36 in order to maintain electrical insulation between the poles. The outer insulating element 35 sits between the tube 13 and the inner nose 31, as shown in Figures 2 and 4. The inner insulating element 34 is seated between the tube 13 and the push bar 22. In this way, outer nose piece 32 can provide electrical continuity between tube 13 and second jaw 16, while inner nose piece 34 can provide electrical continuity between push bar 22 and first jaw 15 . Since push rod 22 is slidably mounted within tube 13, the preferred embodiment has a spring contact 36, as shown in Figures 6 and 7, which is mounted on push rod 22 in order to maintain an electrical connection to the inner nose piece 34 during axial displacement.

The first and second jaws 15 and 16 each have ribs 37 and 38 at their distal ends, which preferably intersect each other. Jaws 15 and 16 also have sealing surfaces 39 and 40, as shown in Figure 2. The width of sealing surfaces 39 and 40 is a parameter that affects the quality of the surgical result. The closing force between jaws 15 and 16 varies along the length of sealing surfaces 39 and 40, such that the greatest force occurs at the distal tip and the smallest force occurs at the proximal end. of the sealing surfaces 39 and 40. It is known that the amount of pressure exerted on the tissue depends on the surface area of ​​the tissue that is in contact with the sealing surfaces. In that embodiment, the width of each sealing surface, for example 39, is in the range of about 2 millimeters to about 5 millimeters, and

ES 2 317 360 T3 is preferably 4 millimeters wide, while the length of each sealing surface 39 and 40 is preferably in the range between approximately 10 and 30 millimeters.

It has been found through experimentation that good vessel sealing results are obtained when the closing force, in grams, divided by the width, in millimeters, is in the range between approximately 400 and 650 grams per millimeter of sealing surface width. . Since the closing force varies with the length of the sealing surfaces 39 and 40, it has been found advantageous to gradually converge or narrow the width of the sealing surfaces 39 and 40 along their length, such that the width The widest is at the proximal end and the narrowest width is at the distal end. For example, if the width of the sealing surface 39, 40 is 4 millimeters, the closing force is preferably in the range of about 1,600 grams to about 2,600 grams. This design allows jaws 15 and 16 to apply a relatively constant clamping force per unit width, preferably 525 grams per millimeter width, yielding a clamping force of 2,100 grams for a sealing surface 39, 40 of 4 millimeters wide.

In one embodiment, the handle 14 includes a fixed handle 50 having a channel 51 defined therein, which slidably receives a movable handle 52. The movable handle 52 includes a hand grip recess 53, defined therein, and which allows a user to move handle 52 relative to fixed handle 50. Movable handle 52 also includes flange 55 having a series of grooves 62, defined therein and mechanically mutually engaging with a corresponding pawl or pawl 60, disposed within channel 51. Preferably, pawl 60 and groove 62 have been dimensioned such that successive ratcheting positions will result in pressures within a predetermined working range of between about 7 kg / cm² and about 13 kg / cm². In one embodiment, successive ratcheting positions are two millimeters apart.

Experimental results from tissue studies suggest that the magnitude of pressure exerted on the tissue by sealing surfaces 39 and 40 is important in ensuring an adequate surgical outcome. Pressures in the tissue within a working range of between approximately 3 kg / cm² and about 16 kg / cm², preferably within a working range of 7 kg / cm² and 13 kg / cm², have been shown to be effective in clogging arteries and vascular bundles. Pressures in the tissue in the range of about 4 kg / cm² and about 6.5 kg / cm² they have been shown to be particularly effective in plugging arteries and tissue bundles.

Also described herein is a method for manufacturing a laparoscopic bipolar electrosurgical instrument 10. The method comprises the step of forming a first jaw 15 having a first flange 18 provided with a first slot 19, as well as a second jaw 16, having a second flange 20 provided with a second groove 21. The jaws 15 and 16 are preferably formed in a casting process, although it is also possible to machine the jaws 15 and 16 from starting material. The casting process can include injecting powdered metal under pressure into a mold and then applying heat.

Other steps of the method include attaching a yoke 17 to a push rod 22, and electrically isolating the first flange 18 from the second flange 20 with the yoke 17. The yoke 17 is preferably an injection molded plastic part that It has characteristics or features that include a first shoulder 29 and a second shoulder 30.

During assembly of the distal portion of instrument 10, method steps include engaging a first pin 25 with first slot 19, and engaging a second pin 26 with second slot 21. Slots 19 and 21 are shaped such that the subtended angle α between the first and second jaws 15 and 16 decreases with distal movement of the push rod 17. The grooves 19 and 20 are formed with culverts or blinds 27 and 28, positioned in such a way as to alleviate the shear stresses on the first and second pins 25 and 26 at the approximate subtended angle α at which the first and second shoulders 29 and 30 mate with the first and second flanges 18 and 20.

Additional steps of the method comprise: surrounding at least a portion of push rod 22 with an electrically conductive tube 13; electrically isolating tube 13 from push rod 22; electrically connecting an inner nose piece 31 to push rod 22; and electrically connecting an outer nose piece 32 with tube 13, such that inner nose piece 31 and outer nose piece 32 capture yoke 17 together with first and second flanges 18 and 20 in order to drive bipolar electrosurgical current to the first and second jaws 15 and 16. In the preferred embodiment there is a step of electrically connecting the push rod 22 and the inner nose piece 31 with a spring contact 36.

The method of manufacturing instrument 10 includes, in some embodiments, the steps of gradually converging or narrowing the width of sealing surfaces 39 and 40 along the length of each of the first and second jaws 15 and 16.

An electrically insulating coating 70 may have been included in order to substantially cover the elongated tube 13 to protect the surgeon from electrical arcs. Other parts of the instrument can also be protected with the insulating coating 70. It is also possible to use an insulating sleeve to cover the tube 13 or other components

2 317 360 T3 of instrument 10, for example, proximal end 11, handles 50, 52, and outer surfaces (non-opposing surfaces) of jaw members 15, 16.

It is contemplated that the outer surface of the jaw members 15 and 16 may include a nickel-based material disposed by coating, stamping, injection molding of the metal, and is designed to reduce adhesion between the jaw members (or components thereof) and surrounding tissue during activation and obturation. Furthermore, it is also contemplated that other components, such as tube 13 and handles 50, 52, may also be coated with the same "non-stick" material or a different material. Preferably, the non-stick materials are of a class of materials that provide a smooth surface in order to avoid mechanical sticking between bumps.

It is also contemplated that the tissue sealing surfaces 39 and 40 of jaw members 15 and 16, respectively, may be manufactured from one (or a combination of one or more) of the following "non-stick" materials: nickel -chromium, chromium nitride, MedCoat 2000, manufactured by The Electrolizing Corporation, of OHIO, Inconel 600 and tin-nickel. For example, alloys with a high nickel / chromium ratio, as well as Ni200, Ni201 (with ~ 100% Ni), can be manufactured in the form of electrodes or sealing surfaces by metal injection molding, stamping, machining or any similar procedure.

In addition, these materials preferably include optimal surface energy to remove adhesion due, in part, to surface texture, as well as susceptibility to surface disruption due to electrical effects and corrosion in the presence of biological tissues. These materials are expected to exhibit superior non-stick qualities over stainless steel and should be used in the instrument in areas where exposure to pressure and RF (radio frequency) energy can create more susceptible localized “hot spots”. to the adhesion of tissues. As can be appreciated, reducing the amount or degree to which the tissue "sticks" during obturation improves the overall effectiveness of the instrument.

The tissue sealing surfaces 39 and 40 may also be "coated" with one or more of the above materials in order to achieve the same result, ie, a "non-stick surface". For example, nitride coatings (or one or more of the above-identified materials) can be deposited as a coating on another base material (metallic or non-metallic) using a vapor deposition fabrication technique.

A particular class of materials described herein has demonstrated superior anti-seize properties and, in some cases, superior sealing quality. For example, nitride coatings that include: TiN, ZrN, TiAlN, and CrN, but are not limited by these, are preferred materials used for anti-stick purposes. CrN has been found to be particularly useful for anti-adherence purposes due to its overall surface properties and performance. Other classes of materials have also been found that reduce overall adhesion. For example, high nickel / chromium alloys, having a Ni / Cr ratio of approximately 5: 1, have been found to significantly reduce adhesion in bipolar instrumentation. A particularly useful non-stick material of this class is Inconel 600. Bipolar instrumentation having electrodes made of or coated with Ni200, Ni201 (with ~ 100% Ni), have also shown improved anti-stick behavior with compared to conventional stainless steel bipolar electrodes.

It has been found experimentally that local current concentrations can give rise to an irregular effect on the tissues and, to reduce the possibility of this event, each sealing surface 39 and 40 can include an edge 80, 81 provided with a certain radius. As mentioned above, a gradually tapered sealing surface 39 and 40 has been shown to be advantageous in certain embodiments because the gradual tapering due to the gradual tapering enables a relatively constant pressure on the tissue, along the length sealing surfaces 39 and 40. The width of the sealing surfaces 39 and 40 can be adjusted so as to ensure that the closing force, divided by the width, is approximately constant along the length.

In one embodiment, a stopper 90, made of an insulating material, is located on the instrument for the purpose of maintaining a minimum clearance of at least about 0.03 millimeters between sealing surfaces 39 and 40, as shown in Figure 3. Preferably, the stop maintains a minimum separation distance in the range of about 0.03 millimeters to about 0.16 millimeters. The stop 90 reduces the possibility of short circuits between the sealing surfaces 39 and 40. It is envisaged that the stop 90 can be located close to the pivots 41 and 42, close to the post 33 or adjacent to the sealing surfaces 39 and 40 capable of being opposed. .

In another embodiment, instrument 10 includes a second stopper or alternative stopper 95 that is designed to maintain a minimum clearance of at least about 0.03 millimeters between sealing surfaces 39 and 40, as shown in Figure 2. Preferably , the stopper 90 and / or the stopper 95 maintain a separation distance within the range of between about 0.03 millimeters and about 0.16 millimeters. A plurality of stops 90 and / or 95 (or various configurations of stops 90, 95) may also be used to achieve this purpose.

ES 2 317 360 T3

The following numbered paragraphs reveal additional aspects of the invention.

Paragraphs

1. A laparoscopic bipolar electrosurgical instrument for tissue obturation, comprising:

a handle, having, attached thereto, an elongated tube, such that the tube includes first and second jaw members, attached to a distal end thereof, so that the jaw members are movable from a first position, to approximate the tissue, to at least one subsequent position to grip the tissue between them, such that each of the jaw members includes an electrically conductive sealing surface, and the handle includes a fixed handle and a movable handle, the movable handle being movable relative to the fixed handle in order to effect movement of the jaw members from the first position to the at least one subsequent position, to the object. to grasp the tissue;

means for connecting the jaw members to a source of electrosurgical energy such that the opposing sealing surfaces are capable of conducting electrosurgical energy through tissue clamped between them;

a stop, intended to maintain a minimum separation distance of at least 0.03 mm between the sealing surfaces capable of opposing; and means for maintaining a closing force in the range of about 3 kg / cm² and about 16 kg / cm² between opposing sealing surfaces.

2. A laparoscopic bipolar electrosurgical instrument according to paragraph 1, in which the connecting means include:

a push rod, adapted to connect the first jaw member to an electrosurgical power source; and a conductive tube, adapted to connect the second jaw member to the electrosurgical power source.

3. A laparoscopic bipolar electrosurgical instrument according to paragraph 1 or paragraph 2, in which the holding means includes a ratchet arranged within the fixed handle, and at least one complementary interlocking mechanical interface, arranged on the handle mobile, such that the ratchet and the complementary interlocking mechanical interface provide at least one interlocking position to maintain a closing force in the range of approximately 7 kg / cm² and about 13 kg / cm² between opposing sealing surfaces.

Four. A laparoscopic bipolar electrosurgical instrument according to any one of the preceding paragraphs, in which the closing force is in the range of about 4 kg / cm² and about 6.5 kg / cm².

5. A laparoscopic bipolar electrosurgical instrument according to any one of the preceding paragraphs, in which the stop has been arranged on at least one of the sealing surfaces.

6. A laparoscopic bipolar electrosurgical instrument according to any one of the preceding paragraphs, in which the stop is arranged adjacent to at least one of the sealing surfaces.

7. A laparoscopic bipolar electrosurgical instrument according to any one of the preceding paragraphs, in which the stop maintains a minimum separation distance between the sealing surfaces in the range between about 0.03 millimeters and about 0.16 millimeters.