Shielding features for ultrasonic blade of a surgical instrument

1. An apparatus comprising:

(a) a body;

(b) a shaft assembly extending distally from the body, wherein the shaft assembly comprises:

(i) an outer sheath, and

(ii) a cap longitudinally fixed to a distal end of the outer sheath;

(c) an end effector located at a distal end of the shaft assembly, wherein the end effector comprises:

(i) an ultrasonic blade, wherein the ultrasonic blade is configured to vibrate at an ultrasonic frequency, and

(ii) a clamp arm, wherein the clamp arm is movable toward the ultrasonic blade to compress tissue against the ultrasonic blade; and

(d) a shield member, wherein the shield member is configured to cover at least a first portion of the end effector, wherein the shield member includes:

(i) a proximal hub, wherein the proximal hub is received within and is longitudinally fixed relative to the cap of the shaft assembly, and

(ii) a shielding portion extending distally from the proximal hub and circumferentially about the first portion,

wherein the proximal hub defines a longitudinal axis, wherein the shielding portion and a length of the first portion extending with the shielding portion extend distally together along a path that deflects away from the longitudinal axis.

2. The apparatus of claim 1 , wherein the path along which the first portion and the shielding portion extend distally is curved.

3. The apparatus of claim 1 , wherein the path along which the first portion and the shield portion extend distally deflects laterally away from the longitudinal axis defined by the proximal hub.

4. The apparatus of claim 1 , wherein the shield member extends circumferentially about first and second lateral sides and an outer side of the first portion of the end effector.

5. The apparatus of claim 4 , wherein the shield member includes an elongate opening extending along an inner tissue engagement side of the first portion of the end effector, wherein the elongate opening exposes the inner tissue engagement side for engaging tissue.

6. The apparatus of claim 1 , wherein the shield member is configured to extend around a distal tip of the first portion of the end effector.

7. The apparatus of claim 1 , wherein the cap surrounds the proximal hub.

8. The apparatus of claim 1 , further comprising a shank pivotably coupled to the shaft assembly, wherein the clamp arm is arranged at a distal end of the shank.

9. The apparatus of claim 8 , wherein a proximal shank end is configured to pivot toward the shaft assembly to move the clamp arm toward the ultrasonic blade, and the proximal shank end is further configured to pivot away from the shaft assembly to move the clamp arm away from the from the ultrasonic blade.

10. The apparatus of claim 1 , wherein a proximal portion of the shield member is configured to fully enclose a proximal portion of the ultrasonic blade.

11. The apparatus of claim 10 , wherein the proximal portion of the shield member includes the proximal hub.

12. An apparatus comprising:

(a) a body;

(b) a shaft assembly extending distally from the body, wherein the shaft assembly includes an outer sheath;

(c) an end effector located at a distal end of the shaft assembly, wherein the end effector comprises:

(i) an ultrasonic blade having a proximal blade portion and a curved distal blade portion, wherein the ultrasonic blade is configured to vibrate at an ultrasonic frequency, and

(ii) a clamp arm, wherein the clamp arm is movable toward the ultrasonic blade to compress tissue against the ultrasonic blade; and

(d) a shield member fixed relative to the outer sheath, wherein the shield member is configured to cover at least a portion of the ultrasonic blade and thereby reduce transfer of heat from the ultrasonic blade to tissue adjacent to the end effector, wherein the shield member includes:

(i) a proximal shield portion configured to fully enclose the proximal blade portion, and

(ii) a distal shield portion configured to partially enclose the curved distal blade portion,

wherein an interior of the distal shield portion extends circumferentially about the curved distal blade portion

wherein the proximal shield portion defines a longitudinal axis, wherein the distal shield portion and the curved distal blade portion extend distally together along a path that deflects away from the longitudinal axis,

wherein the distal shield portion includes an opening that confronts the clamp arm and exposes an inner side of the curved distal blade portion for direct engagement of the inner side with tissue.

13. The apparatus of claim 12 , wherein the opening extends longitudinally with the distal blade portion.

14. The apparatus of claim 12 , wherein a proximal end of the shield member is received within a distal end of the shaft assembly.

15. The apparatus of claim 12 , wherein the distal shield portion is configured to extend around a distal tip of the curved distal blade portion.

16. An apparatus comprising:

(a) a body;

(b) a shaft assembly extending distally from the body;

(c) an end effector located at a distal end of the shaft assembly, wherein the end effector comprises:

(i) an ultrasonic blade, wherein the ultrasonic blade is configured to vibrate at an ultrasonic frequency,

(ii) a clamp arm, wherein the clamp arm includes an inner side that faces the ultrasonic blade and an outer side opposed from the inner side, wherein the clamp arm is movable toward the ultrasonic blade to compress tissue against the ultrasonic blade, and

(iii) a clamp pad coupled to the inner side of the clamp arm, wherein the clamp pad is configured to compress tissue against the ultrasonic blade; and

(d) a shield member coupled to the outer side of the clamp arm so as to define a gap between an interior of the shield member and the outer side of the clamp arm, wherein the shield member is configured to cover at least a portion of the clamp arm and thereby reduce transfer of heat from the clamp arm to tissue being treated by the end effector, wherein the shield member is selectively removable from the clamp arm,

wherein the shield member includes a plurality of openings arranged along a length thereof, wherein the openings extend fully through a thickness of the shield member and are configured to fluidly communicate with the gap.

17. The apparatus of claim 16 , wherein the shield member includes a plurality of engagement elements configured to couple to the clamp arm with a snap-fit engagement.

18. The apparatus of claim 16 , wherein the shield member includes first and second sidewalls defining a cavity therebetween configured to receive the clamp arm when the shield member is coupled to the clamp arm.