Patent Application
20090254081
The present invention is directed to a surgical jaw assembly. More specifically, the present invention is directed to a surgical jaw assembly with an overmold.
Electrosurgical forceps use both mechanical clamping action and electrical energy to affect hemostasis by heating tissue and blood vessels to coagulate, cauterize and/or seal tissue. Instruments, such as a surgical jaw, are inserted into the patient's body to facilitate various tasks during surgical procedures, such as cutting or ligating blood vessels or vascular tissue. Due to the inherent spatial considerations of the surgical cavity, surgeons often have difficulty suturing vessels or performing other traditional methods of controlling bleeding, e.g., clamping and/or tying-off transected blood vessels. By using a surgical jaw assembly, a surgeon can cauterize, coagulate/desiccate and/or reduce or slow bleeding simply by controlling the intensity, frequency and duration of the electrosurgical energy applied through the jaw members to the tissue.
For the purposes herein, “coagulation” is defined as generally a process of desiccating tissue in which the tissue cells are ruptured and dried. “Vessel sealing” or “tissue sealing” is defined generally as the process of liquefying collagen in the tissue so that it reforms into a fused mass. Coagulation of small vessels is ordinarily sufficient to permanently close them, while larger vessels typically need to be sealed to assure permanent closure.
In order to effectively seal vessels (or tissue) two predominant mechanical parameters must be accurately controlled—the pressure applied to the vessel (tissue) and the gap distance between the electrodes—both of which are affected by the thickness of the sealed vessel. More particularly, accurate application of pressure is important to oppose the walls of the vessel; to reduce the tissue impedance to a low enough value that allows enough electrosurgical energy through the tissue; to overcome the forces of expansion during tissue heating; and to contribute to the end tissue thickness which is an indication of a good seal.
Some embodiments of surgical jaw assemblies used for surgical procedures require adhesives, glues or other fasteners to secure the various components of the surgical jaw assembly. During manufacture of the assemblies, each assembly may receive varying amounts of adhesive, resulting in varying thicknesses of adhesive between each electrically conductive surface. A custom stop surface must be added to each assembly after manufacture to provide an accurate predetermined gap distance between the electrically conductive surfaces. The addition of the custom stop surface is inefficient and expensive. Other embodiments of surgical jaw assemblies include forming a premolded datum on a base before assembling the remaining components. The premolded datum adds extra time and costs to manufacturing, however. Therefore what is needed is a surgical jaw assembly without adhesives, glues or fasteners to secure the various components in the surgical jaw assembly. What is also needed is a surgical jaw assembly with a stop surface that is integral with the components.
The present invention is directed to a surgical jaw assembly having a bottom portion. The bottom portion has a first base, a blade disposed in the first base, and a first seal plate disposed on the first base. The first seal plate has an aperture and a flanged edge. The bottom portion also has a first cover at least partially covering the first base. The surgical jaw assembly also has a top portion that has a second base, an insert disposed in the second base, and a second seal plate disposed on the second base. The second seal plate has an aperture and a flanged edge. A second cover at least partially covers the second base. The first seal plate is in contact with the first base and the second seal plate is in contact with the second base. The first cover and second cover covers at least a portion of the first base and at least a portion of the second base, and the first cover secures the blade and first seal plate to the first base by engaging the flanged edge of the seal plate. The second cover secures the insert and second seal plate to the second base by engaging the flanged edge of the seal plate.
The present invention is also directed to a method of manufacturing a surgical jaw assembly having the steps of providing a bottom portion having a first base, a blade, a first seal plate and a first cover. The blade is disposed in the first base and the first seal plate is disposed on the first base such that the first seal plate contacts the first base. The method also includes the step of providing a top portion with a second base, an insert, a second seal plate and a second cover. The insert is disposed in the second base and the second seal plate is disposed on the second base such that the second seal plate contacts the second base. The method also includes overmolding a first cover at least partially surrounding the first base. The first cover secures the blade and first seal plate to the first base such that the first cover engages the first seal plate. Lastly, the method includes overmolding a second cover at least partially surrounding the second base. The second cover secures the insert and second seal plate to the second base such that the second cover engages the second seal plate.
The present invention is further directed to a method of manufacturing a surgical jaw assembly having the steps of providing at least one base and aligning a seal plate with a flanged edge atop the at least one base, such that the seal plate is in contact with the at least one base. Molding a cover at least partially surrounding the at least one base, where the cover secures the seal plate to the at least one base by engaging with the flanged edge of the seal plate.
An advantage of the present invention is the omission of adhesives or fasteners from the assembly to secure the components to one another, thereby producing a precise surgical jaw assembly that is capable of providing the desired pressure and gap distance for procedures.
Yet another advantage of the present invention is the use of injection molding to manufacture the components, thereby creating more uniformity and precision with multiple surgical jaw assemblies.
Still another advantage of the present invention is the use of a stop surface or other feature that is integrated into the surgical jaw assembly, thereby creating more uniformity and precision in the gap distance of surgical jaw assemblies.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
Surgical jaw assembly 10 has a first position and a second position and a plurality of predetermined positions in between. The first position may be an open position (
Top portion 40 and bottom portion 20 may include a stop surface 14. On the top portion 40, stop surface 14 may be disposed on base 42 or may be unitary with base 42. On bottom portion 20, stop surface 14 may be disposed on a base 12 (
Seal plate 18 has an aperture 30 for accepting blade overmold 32 and blade 16. Blade 16 may be used for cutting or severing a vessel or other article. Seal plate 18 is placed over blade 16 and is disposed on base 12. Seal plate 18 is in direct contact with base 12 and electrically common with base 12, thus no separation between seal plate 18, and base 12 is necessary. When seal plate 18 is placed over blade 16, blade 16 is disposed in aperture 30. Blade 16 may securely fit into aperture 30 where there is substantially no additional space between blade 16 and seal plate 18 and such that blade 16 and seal plate 18 are not easily separable from one another once assembled. Alternately, blade 16 and seal plate 18 may be securely assembled such that they are easily removable from each other, when a force is applied to either blade 16 or seal plate 18. Seal plate 18 has flanged edges 24 (
Bottom portion 20 also includes cover 26. Cover 26 substantially surrounds base 12 and secures seal plate 18 and blade 16 to base 12. No additional adhesives or bonds or fasteners are necessary to secure seal plate 18 and blade 16 to base 12. Cover 26 may be plastic or other suitable material. To provide a secure fit to base 12, and seal plate 18, cover 26 may be injection molded to bottom portion 20. In addition to a secure fit, an injection molding process provides uniformity during manufacturing when a plurality of bottom portions 20 are produced. While cover 26 secures blade 16 to base 12, cover 26 may not directly contact blade 16. Alternatively, cover 26 may directly contact blade 16. Blade overmold 32 is disposed in base 12, seal plate 18 is disposed on top of base 12, with blade 16 protruding through aperture 30 of seal plate 18, and cover 26 substantially directly contacts seal plate 18 and base 12.
Surgical jaw assembly 10 may be manufactured or assembled by an exemplary method including the steps of providing a top portion 40 and a bottom portion 20, each having a base. An insert is disposed in the base and seal plate 18 is disposed substantially over the insert onto the base. The insert is exposed through an aperture in the seal plate. It is understood that the insert may protrude through the aperture, partially or completely. A cover is then molded substantially and at least partially over the base and seal plate. The molding of the cover onto the base and the seal plate secures the insert and seal plate to the base without the use of adhesives, glue, bonding materials, or fasteners. The molding process of the cover on the base may include an overmolding process or injection molding process, as well as any other suitable molding process.
Additionally, a blade 16 is disposed in a base and a seal plate 18 is disposed substantially over the blade onto the base. The blade protrudes through an aperture in the seal plate. A cover is then molded substantially and at least partially over the base and the seal plate. The molding of the cover onto the base and the seal plate secures the blade and seal plate to the base without the use of adhesives, glue, bonding material or fasteners. The blade may be molded with blade overmold before being disposed in the base. The blade overmold substantially fits into the aperture of the seal plate. The molding process of the cover on the base may include an overmolding process or injection molding process, as well as any other suitable molding process.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
