Surgical instruments with articulating shafts

An articulatable surgical instrument comprising:

• an end effector to treat tissue, wherein the end effector comprises an ultrasonic blade;
• a shaft extending proximally from the end effector along a longitudinal axis wherein the shaft comprises a flexible portion;
• a waveguide acoustically coupled to the ultrasonic blade and extending proximally through the shaft, wherein the waveguide comprises a bendable waveguide portion at about the flexible shaft portion, and wherein the waveguide comprises:
• a first flange positioned at a node of the waveguide distal from the bendable waveguide portion and coupled to an interior of the shaft;
• a second flange positioned at a node of the waveguide proximate from the bendable waveguide portion and coupled to an interior of the shaft;
• a first control member coupled to the first flange and extending proximally through the second flange and shaft, such that proximal translation of the first control member pulls the first flange proximally, causing the shaft and waveguide to pivot away from the longitudinal axis towards the first control member.

An articulatable surgical instrument comprising:

• an end effector to treat tissue;
• an outer shaft extending along a longitudinal axis;
• an inner shaft at least partially within the outer shaft, the inner shaft extending proximally from the end effector, wherein the inner shaft comprises a biased portion that is biased to bend away from the longitudinal axis in a first direction;
• wherein the inner shaft and the outer shaft are translatable relative to one another to a first position where the biased portion of the inner shaft is within the outer shaft and the inner shaft is substantially straight along the longitudinal axis;
• and
• wherein the inner shaft and the outer shaft are translatable relative to one another to a second position where the biased portion of the inner shaft is outside of and distally positioned from the outer shaft such that the biased portion of the inner shaft is bent away from the longitudinal axis in the first direction.