Method of transferring rotational motion in an articulating surgical instrument
An endoscopic surgical instrument includes an elongated shaft, which may be articulated to facilitate positioning of an end effector. The instrument accommodates reactionary forces associated with closing the end effector without substantial disruption to the position of the end effector. The instrument includes an elongated shaft housing generally defining distal and proximal shaft axes, and a torsion member extending through the shaft housing. The torsion member transmits rotational displacement from a handle portion of the instrument to the end effector to selectively move the end effector between open and closed configurations. The torsion member comprises a flexible shaft exhibiting a plurality of generally radial slots spaced longitudinally along a length of the flexible shaft.
1. A surgical instrument, comprising:
a shaft housing including distal and proximal ends, the distal end of the shaft housing generally defining a distal shaft axis and the proximal end of the shaft housing generally defining a proximal shaft axis;
a torsion member extending through the shaft housing and including distal and proximal ends, the distal end of the torsion member configured for rotational movement in response to rotational movement of the proximal end of the torsion member;
an end effector coupled to the distal end of the shaft housing, the end effector moveable between open and closed configurations in response to rotational movement of the distal end of the torsion member; and
a handle coupled to the proximal end of the shaft housing, the handle including an actuation mechanism configured to selectively induce rotational movement at the proximal end of the torsion member;
wherein the torsion member comprises a flexible shaft having a plurality of generally radial slots defined in spaced longitudinal orientation along a length of the flexible shaft.
2. The instrument according to claim 1 , wherein the torsion member comprises an elongated tube defining a lumen therethrough.
3. The instrument according to claim 2 , wherein the elongated tube is constructed of stainless steel.
4. The instrument according to claim 1 , wherein the plurality of slots includes at least two opposed slots radially spaced relative to one another by about 180 degrees.
5. The instrument according to claim 1 , wherein the plurality of slots includes at least three slots radially displaced relative to one another by about 120 degrees.
6. The instrument according to claim 1 , wherein the shaft housing is flexible along a length thereof and sufficiently rigid to support the end effector in a position when the shaft housing is disposed in a misaligned configuration.
7. The instrument according to claim 1 , wherein the end effector includes a pair of opposable jaw members.
8. The instrument according to claim 6 , wherein at least one of the jaw members of the pair of opposable jaw members is coupled to a source of electro surgical energy.
9. The instrument according to claim 1 , wherein the end effector includes an input shaft coupled to the torsion member configured to receive rotational motion therefrom, and wherein the input shaft is coupled to a power screw that drives a translation nut longitudinally upon rotational motion of the power screw.
10. The instrument according to claim 1 , wherein the actuation mechanism of the handle includes a nut operatively coupled to a moveable handle such that movement of the movable handle moves the nut longitudinally, and wherein the nut is coupled to a lead screw such that longitudinal motion of the nut drives rotational motion of the lead screw.
11. A surgical instrument, comprising:
an elongated shaft housing including distal and proximal ends, the distal end of the shaft housing generally defining a distal shaft axis and the proximal end of the shaft housing generally defining a proximal shaft axis;
a torsion member extending through the shaft housing and including distal and proximal ends, the distal end of the torsion member configured for rotational movement in response to rotational movement of the proximal end of the torsion member;
an end effector coupled to the distal end of the shaft housing, the end effector moveable between open and closed configurations in response to rotational movement of the distal end of the torsion member; and
a handle coupled to the proximal end of the shaft housing, the handle including an actuation mechanism configured to selectively induce rotational movement at the proximal end of the torsion member;
wherein the torsion member includes a plurality of substantially rigid segments coupled to one another by universal joints or constant velocity joints.