# Patent

## Title
Method of manufacturing an electrosurgical instrument

## Abstract

A method for manufacturing a pair of jaw members configured for use with an electrosurgical forceps is provided. One or more pairs of seal plates are stamped from a sheet metal. The seal plates are positioned into respective mold cavities. An insulative substrate is introduced into the respective mold cavities. The insulative substrate is allowed to harden in the respective mold cavities to form respective jaw housings with seal plates secured thereto. The jaw housings are removed from the respective mold cavities to form a pair of jaw members.

## Background
BACKGROUND
1. Technical Field
The present disclosure relates to an electrosurgical instrument and, more particularly, to a method of manufacturing jaw members configured for use with an electrosurgical forceps.
2. Description of Related Art
Electrosurgical forceps are well known in the medical arts. For example, an electrosurgical endoscopic forceps is utilized in surgical procedures, e.g., laparoscopic surgical procedures, where access to tissue is accomplished through a cannula or other suitable device positioned in an opening on a patient. The endoscopic forceps, typically, includes a housing, a handle assembly including a movable handle, a drive assembly, a shaft and an end effector assembly attached to a distal end of the shaft. The endoscopic forceps may utilize both mechanical clamping action and electrical energy to effect hemostasis by heating the tissue and blood vessels to coagulate, cauterize, seal, cut, desiccate, and/or fulgurate tissue. In particular, the jaw members operably communicate with the drive assembly to manipulate tissue, e.g., grasp tissue, and the jaw members have respective seal plates secured to the jaw housing of the respective jaw members to seal tissue.
Manufacturing the jaw members of the end effector, typically, is a complex and lengthy process. In particular, the intricate components of the jaw members are, initially, machined and, subsequently, assembled. As can be appreciated, this adds to the overall costs of the manufacture of the endoscopic forceps.
SUMMARY
Embodiments of the present disclosure are described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical elements. As used herein, the term “distal” refers to the portion that is being described which is further from a user, while the term “proximal” refers to the portion that is being described which is closer to a user.
An aspect of the present disclosure provides a method for manufacturing a pair of jaw members configured for use with an electrosurgical forceps. One or more pairs of seal plates are stamped from a sheet metal. The seal plates are positioned into respective mold cavities. An insulative substrate is introduced into the respective mold cavities. The insulative substrate is allowed to harden in the respective mold cavities to form respective jaw housings with seal plates secured thereto. And, the jaw housings are removed from the respective mold cavities to form a pair of jaw members.
According to a further aspect of the instant disclosure, the method may include deforming the seal plates with a die to form the seal plates with a generally “U” shaped configuration.
According to another aspect of the present disclosure, the method may further positioning a knife channel mold into at least one of the mold cavities to form a knife channel within the respective jaw housing, the knife channel configured for reciprocation of a knife blade therethrough.
According to yet another aspect of the present disclosure, either a one-shot or two-shot injection molding process may be utilized in the step of introducing the insulative substrate.
According to still yet another aspect of the present disclosure, the method may include introducing an insulative substrate that is made from one of a thermosetting plastic and a thermoplastic.
According to another aspect of the present disclosure, the method may include positioning at least one electrode into at least one of the mold cavities. In this instance, the electrode may be configured to sever electrosurgically treated tissue positioned between the pair of jaw members upon activation thereof.
In certain instances, deforming the seal plates may include deforming the seal plates to include a pinch trim configured to facilitate securing the seal plates to respective insulative jaw housings.
In certain instances, positioning the seal plates may include positioning the seal plates in the mold cavities such that the seal plates extend a predetermined distance past a top surface of the respective insulative jaw housings when the insulative jaw housings have hardened.
The method may include the step of securing the pair of jaw members to a distal end of the electrosurgical forceps.
An aspect of the present disclosure provides a method for manufacturing a pair of jaw members configured for use with an electrosurgical forceps. One or more pairs of seal plates are stamped from a sheet metal. The stamped out seal plates are deformed with a die to provide the seal plates with a sealing surface portion and a structural insert portion. The seal plates are positioned into respective mold cavities. A curable insulative substrate is introduced into the respective mold cavities such that the insulative substrate covers the structural insert portion of the seal plates. The insulative substrate is allowed to cure in the respective mold cavities to form respective jaw housings with seal plates secured thereto. And, the jaw housings are removed from the respective mold cavities to form a pair of jaw members.
According to a further aspect of the instant disclosure, the method may include deforming the seal plates with a die to form the seal plates with a generally “U” shaped configuration.
According to another aspect of the present disclosure, the method may further positioning a knife channel mold into at least one of the mold cavities to form a knife channel within the respective jaw housing, the knife channel configured for reciprocation of a knife blade therethrough.
According to still yet another aspect of the present disclosure, the method may include introducing a curable insulative substrate that is made from one of a thermosetting plastic and a thermoplastic.
According to another aspect of the present disclosure, the method may include positioning at least one electrode into at least one of the mold cavities. In this instance, the electrode may be configured to sever electrosurgically treated tissue positioned between the pair of jaw members upon activation thereof.
In certain instances, deforming the seal plates may include deforming the seal plates to include a pinch trim configured to facilitate securing the seal plates to respective insulative jaw housings.
In certain instances, positioning the seal plates may include positioning the seal plates in the mold cavities such that the seal plates extend a predetermined distance past a top surface of the respective insulative jaw housings when the insulative jaw housings have hardened.
The method may include the step of securing the pair of jaw members to a distal end of the electrosurgical forceps.



BRIEF DESCRIPTION OF THE DRAWING
Various embodiments of the present disclosure are described hereinbelow with references to the drawings, wherein:
FIG. 1 is a perspective view of an endoscopic electrosurgical forceps utilizing an end effector including jaw members manufactured according to an embodiment of the present disclosure;
FIG. 2A is a cross-sectional view of the jaw members depicted in FIG. 1;
FIG. 2B is a cross-sectional view of jaw members according to another embodiment of the present disclosure;
FIG. 2C is a top elevational view of one of the jaw members depicted in FIG. 2B;
FIG. 2D is a top elevational view of an alternate configuration of the jaw members;
FIG. 3 is a cross-sectional view of an alternate configuration of the jaw members; and
FIG. 4 is a flow-chart illustrating a method of manufacture of the end effector assembly depicted in FIG. 1 according to an embodiment of the present disclosure.



DETAILED DESCRIPTION
Detailed embodiments of the present disclosure are disclosed herein; however, the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
Turning now to FIG. 1, an electrosurgical endoscopic forceps 10 (forceps 10) is provided having a longitudinal axis “A-A” defined therethrough, a housing 20, a handle assembly 30, a rotating assembly 70, a trigger assembly 80 and an end effector assembly 100. Forceps 10 further includes a shaft 12 having a distal end 14 configured to mechanically engage end effector assembly 100 and a proximal end 16 that mechanically engages housing 20. Forceps 10 also includes electrosurgical cable 610 that connects forceps 10 to a generator (not shown) or other suitable power source. Alternately, forceps 10 may be configured as a battery powered instrument. Cable 610 includes one or more wires (not shown) extending therethrough that has sufficient length to extend through shaft 12 in order to provide electrical energy to at least one of the jaw members 110 and 120 of end effector assembly 100.
Continuing with reference to FIG. 1, end effector assembly 100 is designed as a unilateral assembly. In the unilateral jaw assembly jaw member 120 is fixed relative to shaft 12 and jaw member 110 is moveable about a pivot 103 relative to shaft 12 and fixed jaw member 120. End effector assembly 100, however, may alternatively be configured as a bilateral assembly, e.g., where both jaw member 110 and jaw member 120 are moveable about the pivot 103 relative to one another. In some embodiments, a knife assembly is disposed within shaft 12 and a knife channel 13 (FIG. 2B) is defined within one or both jaw members 110, 120 to permit reciprocation of a knife blade 19 therethrough, e.g., via activation of trigger 82 (FIG. 1) of trigger assembly 80. Other than jaw member 110 being movable and jaw member 120 being stationary, jaw members 110 and 120 are identical to one another. In view thereof, and unless otherwise noted, only jaw member 120 is described in detail below.
Turning now to FIG. 2A, jaw members 110 and 120 are illustrated disposed in opposing relation to one another. Jaw member 120 includes a jaw housing 124 that is used to encapsulate a seal plate 122 (FIG. 2A). Jaw housing 124 may be made from any suitable material including, but not limited to, plastic, ceramic material, etc. In the illustrated embodiment, jaw housing 124 is made from plastic and serves as an insulative substrate, described in more detail below. In certain embodiments, it may prove advantageous to provide an exterior portion of the jaw housing 124 that is made from metal and an interior portion (e.g., a portion that is configured to support the seal plate 122 thereon) of the jaw housing 124 that is made from plastic. In this instance, the interior portion serves as an insulative barrier between the seal plate 122 and the exterior portion of the jaw housing 124.
Continuing with reference to FIG. 2A, seal plate 122 includes a sealing surface portion 123a (illustrated by phantom lines “A”) that is configured to seal tissue and a structural insert portion 123b (illustrated by phantom lines “B”) that is configured to secure to jaw housing 124. The structural insert portion 123b of the seal plate 122 includes sidewalls 125a and 125b that extend parallel to one another and converge at back wall 125c. Sealing surface portion 123a has a split configuration having a generally u-shape (as best seen in FIG. 2C). Alternately, the sealing surface portion 123a may have a split configuration having two parallel surfaces that do not meet at a distal end thereof, see FIG. 2C for example. An optional pinch trim 126 may extend along a peripheral edge 128 of the seal surface portion 123a (FIGS. 2A-3). Pinch trim 126 facilitates securing seal plate 122 to the jaw housing 124 during the manufacturing process of the jaw member 120. The seal surface portion 123a and a structural insert portion 123b collectively form a generally “U” configuration (see FIG. 2A, for example), the significance of which described in greater detail below.
Likewise, jaw member 110 includes an opposing electrically conductive tissue sealing plate 112 that includes a sealing surface portion 127a that is configured to seal tissue and a structural insert portion 127b that is configured to secure to jaw housing 118. (FIG. 2A). The structural insert portion 127b includes sidewalls 129a and 129b that extend parallel to one another and converge at a back wall 129c. As with sealing surface portion 123a, sealing surface portion 127a has a split configuration having a generally u-shape and may include a pinch trim 119 that is similar to pinch trim 126. Pinch trim 119 may extend along a peripheral edge 131 of the seal surface portion 127a (FIG. 2A). The seal surface portion 127a and a structural insert portion 127b collectively form a generally “U” cross-section (see FIG. 2A, for example).
Unlike conventional jaw members that are manufactured via a machining process, the jaw members 110 and 120 of the instant disclosure are manufactured via a stamping and overmolding process. Initially, and in one particular embodiment, a pair of seal plates 112 and 122 is formed via a stamping process. Sheet metal of suitable configuration is provided (see FIG. 4 at step 202). In the illustrated embodiments, a stamping or machine press (not shown) is utilized to cut or “punch” the sheet-metal to a desired configuration (see FIG. 4 at step 204). Subsequently, the stamping press is utilized to shape the “punched” sheet-metal into one or more suitable configurations by deforming it with a die or other suitable device (not shown). In accordance with the instant disclosure, the seal plates 112 and 122 are formed with the generally “U” cross-section corresponding to a finished configuration of the respective jaw housings 118 and 124, as best seen in FIGS. 2A and 2B. It has been observed that this “U” cross-section provides the requisite structural rigidity for the respective jaw housing 118 and 124 of the jaw members 110 and 120.
In accordance with the present disclosure, the aforementioned stamping process may include a variety of other sheet-metal manufacturing processes, such as, for example, blanking, embossing, bending, flanging, and coining. In this instance, the stamping process could be a single stage operation where every stroke of the stamping press produces a desired form on a sheet-metal part, or could occur through a series of stages. For example, it may prove advantageous to bend the seal plates 112 and 122 (or portions thereof) after the seal plates 112 and 122 have been deformed by the die. In certain instances, for example, the peripheral edges 128 and 131 may be bent to form the respective pinch trims 126 and 119.
After the sheet-metal is formed into the seal plates 112 and 122, each seal plate 112 and 122 is positioned into a mold cavity (not shown) of suitable configuration (see FIG. 4 at step 206) and overmolded with an insulative substrate (see FIG. 4 at step 206) that substantially encapsulates the seal plates 112 and 122 and forms the outer jaw housing 118 and 124 of the respective jaw members 110 and 120 (FIG. 2A). The mold cavity is shaped to correspond to a desired jaw housing configuration. In one particular embodiment, such as the illustrated embodiment, the mold cavity may be configured to provide jaw members 110 and 120 with a lower jaw profile when compared to conventional jaw members. Advantages of having jaw members 110 and 120 with a lower jaw profile include, but are not limited to better visualization around the jaws, better access to critical structures and contouring of the jaw members 110 and 120 such that the jaw members 110 and 120 can be used for dissection of tissue.
In one particular embodiment, the insulative substrate, such as, for example, a thermoplastic or thermosetting plastic in liquid form, is fed into a barrel (not shown), which may be heated, mixed, and introduced into the mold cavity where it cools and hardens (or cures) to the configuration of the mold cavity. A “single-shot” or “two-shot” injection molding process may be utilized to introduce the liquid insulative substrate into the mold cavity (see FIG. 4 at step 208).
Pinch trims 119 and 126 of the respective seal plates 112 and 122 (FIG. 2A) facilitate securing the seal plates 112 and 122 to the respective insulative jaw housings 118 and 124 during the manufacturing process. That is, the pinch trims 119 and 126 are encapsulated by the liquid insulative substrate during the overmolding process to reinforce the bond between the insulative housing 118 and 124 and the respective sealing surface portions 127a and 123a. 
In certain embodiments, such as the embodiment illustrated in FIG. 2B, it may prove advantageous to provide one or more knife channels 13 on one or both of the jaw members 110 and 120. In this instance, the step of overmolding the seal plates 112 and 122 with an insulative substrate includes forming a knife channel 13 in the insulation of each seal plate 112 and 122. In this instance, before the insulating substrate is allowed to harden, a knife channel mold (not shown) is positioned in the mold cavity, e.g., between the sidewalls 129a, 129b and 125a, 125b of seal plates 112 and 122, respectively. In certain instances, this may be accomplished prior to introducing the liquid insulative substrate into the mold cavity.
After the insulative substrate hardens and the insulative jaw housings 118 and 124 are formed (see FIG. 4 at step 210), the insulative jaw housing 118 and 124 including the respective seal plates 112 and 122 secured thereto may be removed from their respective mold cavities (see FIG. 4 at step 212). The knife mold may be removed at any time after the insulative substrate hardens. In the hardened (or cured) configuration, the seal plates 112 and 122 extend a predetermined distance past a top surface of the respective insulative jaw housings 118 and 124 (FIG. 2A). In addition, the seal plates 112 and 122 will follow an overall contour of the insulative jaw housings 118 and 124, respectively; this is illustrated in FIG. 2C with respect to seal plate 122 and jaw housing 124.
In an assembled configuration, the jaw members 110 and 120 are secured to the distal end 14 of the shaft via one or more suitable securement methods. As with conventional jaw member configurations, jaw members 110 and 120 are operable to grasp and, subsequently, seal tissue.
The aforementioned stamping and overmolding process utilized to manufacture jaw members 110 and 120 is a simple and low cost alternative to conventional machining processes.
In addition, the aforementioned stamping and overmolding process provides jaw members 110 and 120 with lower profiles when compared to conventional jaw members. As can be appreciated, a forceps 10 that includes jaw members 110 and 120 with low profiles may be better suited in surgical procedures where access to a surgical site is through an access port of relatively small configuration, e.g., less than 5 mm.
Further, while not discussed in great detail above, electrical pathways can be created in the insulative jaw housing 118 and 124 by leaving portions of the seal plates 118 and 128 exposed from the insulative jaw housing 118 and 124 (e.g., at a proximal end of the respective jaw housings 118 and 124) during the overmolding process (alternately, wires may be soldered to the seal plates 118 and 128 prior to the overmolding). In this instance, for example, the pivot pin 103 or cam pin (not shown) may be configured to transmit electrosurgical energy to the seal plates 118 and 124. Accordingly, the need for a wire (or wires) extending through the shaft 12 may be eliminated, which, in turn, may decrease the overall manufacturing cost of the forceps 10.
From the foregoing, and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, in certain embodiments, it may prove advantageous to utilize an electrode 130 (FIG. 3) instead of a knife blade to sever tissue. In this instance, one or both of the jaw members, e.g., jaw member 110, may include an electrode 130 in addition to the seal plate 112. In this instance, the step of stamping a pair of seal plates 118 and 128 includes stamping an electrode 130, which may also serve as a structural insert portion for the jaw member 110. In the embodiment illustrated in FIG. 3, jaw member 110 may include a pair of seal plates 112a and 112b (or a seal plate 112 as described above) and the electrode may be positioned therebetween. A method similar to positioning the knife channel mold in the mold cavity may be utilized to position the electrode 130 with respect to the pair of seal plates 112. Unlike the knife channel mold, however, the electrode 130 is configured to remain in the hardened insulative substrate, e.g., the jaw housing 124.
In certain embodiments, the aforementioned mold cavities may be treated with one or more suitable substances configured to facilitate removing the hardened insulative jaw housings 118 and 124 from the mold cavities. Alternately, the mold cavity may be made from one or more non-stick substances, e.g., polytetrafluoroethylene (PTFE).
While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

## Claims

1. A method for manufacturing a jaw member configured for use with an electrosurgical forceps, comprising:
stamping a seal plate from a sheet metal, wherein the seal plate includes a centrally disposed structural insert portion and two sealing surface portions depending from the structural insert portion, the two sealing surface portions configured to contact tissue and being separated by a gap, wherein an entirety of the seal plate is monolithically formed;
positioning the seal plate into a mold cavity;
introducing an insulative substrate into the mold cavity;
positioning a knife channel mold into the mold cavity such that the knife channel is free from contact with the seal plate, the knife channel configured for reciprocation of a knife blade therethrough;
allowing the insulative substrate to harden in the mold cavity to form a jaw housing with the seal plate secured thereto; and
removing the jaw housing from the mold cavity to form the jaw member.

2. The method according to claim 1, including the step of deforming the seal plate with a die to form the seal plate with a generally “U” shaped configuration.

3. The method according to claim 2, wherein the step of deforming the seal plate includes deforming the seal plate to include a pinch trim configured to facilitate securing the seal plate to the jaw housing.

4. The method according to claim 1, wherein one of a one-shot or two-shot injection molding process is utilized in the step of introducing the insulative substrate.

5. The method according to claim 1, wherein the step of introducing the insulative substrate includes introducing an insulative substrate that is made from one of a thermosetting plastic and a thermoplastic.

6. The method according to claim 1, further including the step of positioning at least one electrode into the mold cavity.

7. The method according to claim 1, wherein positioning the seal plate includes positioning the seal plate in the mold cavity such that the seal plate extends a predetermined distance past a top surface of the jaw housing when the jaw housing has hardened.

8. The method according to claim 1, further including the step of securing the jaw member to a distal end of the electrosurgical forceps.

9. A method for manufacturing a jaw member configured for use with an electrosurgical forceps, comprising:
stamping a seal plate from a single piece of sheet metal;
deforming the seal plate with a die to provide the seal plate with two sealing surface portions interconnected by a centrally disposed structural insert portion, wherein the two sealing surface portions are separated by a gap;
positioning the seal plate into a mold cavity;
introducing a curable insulative substrate into the mold cavity such that the insulative substrate encases the structural insert portion of the seal plate;
positioning a knife channel mold into the mold cavity such that the knife channel is free from contact with the seal plate, the knife channel configured for reciprocation of a knife blade therethrough;
allowing the insulative substrate to cure in the mold cavity to form a jaw housing with the seal plate secured thereto; and
removing the jaw housing from the mold cavity to form a jaw member.

10. The method according to claim 9, wherein the deforming step includes deforming the seal plate such that the sealing surface portions and structural insert portion collectively form the seal plate with a generally “U” shaped configuration.

11. The method according to claim 9, wherein the step of introducing the curable insulative substrate includes introducing a curable insulative substrate that is made from one of a thermosetting plastic and a thermoplastic.

12. The method according to claim 9, further including the step of positioning at least one electrode into the mold cavity.

13. The method according to claim 9, wherein the step of deforming the seal plate includes deforming the seal plate to include a pinch trim configured to facilitate securing the seal plate to the jaw housing.

14. The method according to claim 9, wherein positioning the seal plate includes positioning the seal plate in the mold cavity such that the seal plate extends a predetermined distance past a top surface of the jaw housing when the jaw housing has hardened.

15. The method according to claim 9, further including the step of securing the jaw member to a distal end of the electrosurgical forceps.