Electrosurgical instrument which reduces collateral damage to adjacent tissue

1. An electrode assembly for use with an electrosurgical instrument having opposing end effectors and a handle for effecting movement of the end effectors relative to one another, comprising:

a housing having at least one portion which removably engages at least one portion of the electrosurgical instrument;

a pair of electrodes each including an electrically conductive sealing surface and an insulating substrate, the electrodes being removably engageable with respective end effectors of the electrosurgical instrument such that the electrodes reside in opposing relation relative to one another, the dimensions of the insulating substrate differing from the dimensions of the electrically conductive sealing surface to reduce thermal spread to adjacent tissue structures, the insulating substrate having first and second lateral edges; and

at least one compliant material disposed proximate the outer periphery of at least one of the electrodes and along either of the first and second lateral edges of the insulating substrate such that either of the first and second lateral edges of the insulating substrate are disposed between the at least one compliant material and either of corresponding first and second lateral edges of the electrically conductive sealing surface, the at least one compliant material having a height dimension sufficient to project an edge of the at least one compliant material above the first and second lateral edges of the electrically conductive sealing surfaces, the at least one compliant material configured thereby to reduce thermal spread from either of the first and second lateral edges of the electrically conductive sealing surface to surrounding tissue.

2. An electrode assembly according to claim 1 wherein the at least one compliant material is dimensioned to restrict heat and steam emanating from the sealing surface when the electrode assembly is activated.

3. An electrode assembly according to claim 1 wherein a plurality of the at least one compliant material is attached to at least one of the end effectors and the insulating substrates of the electrode assembly.

4. An electrode assembly according to claim 1 wherein the insulating substrate is made from a material having Comparative Tracking Index of about 300 volts to about 600 volts.

5. An electrode assembly according to claim 1 wherein the insulating substrate is selected from the group consisting of nylon, syndiotactic-polystryrene, polybutylene terephthalate, polycarbonate, acrylonitrile butadiene styrene, polyphthalamide, polymide, polyethylene terephthalate, polyamide-imide, acrylic, polystyrene, polyether sulfone, aliphatic polyketone, acetal copolymer, polyurethane, nylon with polyphenylene-oxide dispersion and acrylonitrile styrene acrylate.

6. An electrode assembly according to claim 1 , further comprising a stamped seal plate stamping overmold wherein the insulating substrate is mounted to the electrically conductive sealing surface by the stamped seal plate stamping overmold.

7. An electrode assembly according to claim 1 , further comprising a metal injection molded seal plate molding overmold, wherein the insulating substrate is mounted to the electrically conductive sealing surface by the metal injection molded seal plate molding overmold.

8. An electrode assembly according to claim 1 wherein the electrically conductive sealing surface of at least one electrode includes the a pinch trim and the insulating substrate extends beyond a periphery of the electrically conductive sealing surface.

9. An electrode assembly according to claim 1 wherein the insulating substrate of each of the electrodes includes at least one mechanical interface for engaging a complementary mechanical interface disposed on the corresponding end effector of the instrument.

10. An electrode assembly according to claim 1 wherein the electrode assembly is disposable.

11. An electrode assembly for use with a disposable electrosurgical instrument having a handle and at least one shaft for effecting movement of a pair of opposing end effectors relative to one another, comprising:

a pair of electrodes each having an electrically conductive sealing surface having a first geometric shape and an insulating substrate having a second geometric shape, the electrodes being integrally associated with respective end effectors of the instrument such that the electrodes reside in opposing relation relative to one another;

a seal plate; and

a compliant material disposed proximate the outer periphery of at least one of the electrodes and along lateral edges of the insulating substrate such that the lateral edges of the insulating substrate are disposed between the at least one compliant material and corresponding lateral edges of the electrically conductive sealing surface, the at least one compliant material having a height dimension sufficient to project an edge of the at least one compliant material beyond the lateral edges of the corresponding electrically conductive sealing surface, the at least one compliant material configured thereby to reduce thermal spread to surrounding tissue from the lateral edges of the electrically conductive sealing surface,

wherein the insulating substrate is mounted to the electrically conductive sealing surface by the seal plate.

12. An electrode assembly for use with an electrosurgical instrument having opposing end effectors and a handle for effecting movement of the end effectors relative to one another, comprising:

a housing having at least one portion which removably engages at least one portion of the electrosurgical instrument;

a pair of electrodes each including an electrically conductive sealing surface and an insulating substrate, the electrodes being removably engageable with respective end effectors of the electrosurgical instrument such that the electrodes reside in opposing relation relative to one another, the dimensions of the insulating substrate differing from the dimensions of the electrically conductive sealing surface to reduce thermal spread to adjacent tissue structures, the insulating substrate having first and second lateral edges;

at least one compliant material disposed proximate the outer periphery of at least one of the electrodes and along either of the first and second lateral edges of the insulating substrate such that either of the first and second lateral edges of the insulating substrate are disposed between the at least one compliant material and either of corresponding first and second lateral edges of the electrically conductive sealing surface, the at least one compliant material having a height dimension sufficient to project an edge of the at least one compliant material above the first and second lateral edges of the corresponding electrically conductive sealing surface, the at least one compliant material configured thereby to reduce thermal spread from either of the first and second lateral edges of the electrically conductive sealing surface to surrounding tissue; and

a stamping overmold wherein the insulating substrate is mounted to the electrically conductive sealing surface by the stamping overmold.

13. An electrode assembly for use with an electrosurgical instrument having opposing end effectors and a handle for effecting movement of the end effectors relative to one another, comprising:

a housing having at least one portion which removably engages at least one portion of the electrosurgical instrument;

a pair of electrodes each including an electrically conductive sealing surface and an insulating substrate, the electrodes being removably engageable with respective end effectors of the electrosurgical instrument such that the electrodes reside in opposing relation relative to one another, the dimensions of the insulating substrate differing from the dimensions of the electrically conductive sealing surface to reduce thermal spread to adjacent tissue structures, the insulating substrate having first and second lateral edges;

at least one compliant material disposed proximate the outer periphery of at least one of the electrodes and along either of the first and second lateral edges of the insulating substrate such that either of the first and second lateral edges of the insulating substrate are disposed between the at least one compliant material and either of corresponding first and second lateral edges of the electrically conductive sealing surface, the at least one compliant material having a height dimension sufficient to project an edge of the at least one compliant material above the first and second lateral edges of the corresponding electrically conductive sealing surface, the at least one compliant material configured thereby to reduce thermal spread from either of the first and second lateral edges of the electrically conductive sealing surface to surrounding tissue; and

a metal injection molding overmold, wherein the insulating substrate is mounted to the electrically conductive sealing surface by the metal injection molding overmold.

14. An electrode assembly for use with an electrosurgical instrument having opposing end effectors and a handle for effecting movement of the end effectors relative to one another, comprising:

a housing having at least one portion which removably engages at least one portion of the electrosurgical instrument;

a pair of electrodes each including an electrically conductive sealing surface and an insulating substrate, the electrodes being removably engageable with respective end effectors of the electrosurgical instrument such that the electrodes reside in opposing relation relative to one another, the dimensions of the insulating substrate differing from the dimensions of the electrically conductive sealing surface to reduce thermal spread to adjacent tissue structures, the insulating substrate having first and second lateral edges;

at least one compliant material disposed proximate the outer periphery of at least one of the electrodes and along either of the first and second lateral edges of the insulating substrate such that either of the first and second lateral edges of the insulating substrate are disposed between the at least one compliant material and either of corresponding first and second lateral edges of the electrically conductive sealing surface, the at least one compliant material having a height dimension sufficient to project an edge of the at least one compliant material above the first and second lateral edges of the corresponding electrically conductive sealing surface, the at least one compliant material configured thereby to reduce thermal spread from either of the first and second lateral edges of the electrically conductive sealing surface to surrounding tissue; and

the electrically conductive sealing surface of at least one electrode including a pinch trim and the insulating substrate extends beyond a periphery of the electrically conductive sealing surface.