Push-pull surgical instrument end effector actuation using flexible tension member
Surgical tools and related methods articulate an actuation rod via a flexible tension member. A surgical tool includes a proximal actuation assembly, an end effector, an instrument shaft assembly, and a flexible tension member. The instrument shaft assembly includes an instrument shaft that defines a lumen and an actuation rod assembly comprising an actuation rod that extends within the lumen. The instrument shaft supports the end effector. The actuation rod is drivingly coupled with the end effector. The flexible tension member drivingly couples the actuation rod to the proximal actuation assembly. The proximal actuation assembly is operable to increase tension in the flexible tension member to move the actuation rod toward the end effector to actuate the end effector.
1 . A surgical tool comprising:
a proximal assembly comprising an actuation mechanism;
an end effector;
an instrument shaft assembly comprising an instrument shaft and an actuation rod assembly, wherein the instrument shaft is rotatably coupled to the proximal assembly and comprises a lumen, wherein the actuation rod assembly comprises an actuation rod that extends within the lumen, wherein the instrument shaft supports the end effector, and wherein the actuation rod is drivingly coupled with the end effector;
a rotatable element disposed within the instrument shaft;
wherein the actuation mechanism is operable to rotate the instrument shaft relative to the proximal assembly and the actuation rod is constrained to rotate with the instrument shaft; and
a flexible tension member in contact with the rotatable element and drivingly coupling the actuation rod to the actuation mechanism, wherein the actuation mechanism is operable to increase tension in the flexible tension member to move the actuation rod toward the end effector to actuate the end effector.
2 . The surgical tool of claim 1 , wherein the actuation mechanism is operable to increase tension in the flexible tension member to move the actuation rod away from the end effector.
3 . The surgical tool of claim 2 , wherein:
the instrument shaft assembly comprises an isolation tube through which the flexible tension member extends, wherein the isolation tube isolates the flexible tension member from a region of the lumen surrounding the isolation tube.
4 . The surgical tool of claim 1 , wherein the actuation rod assembly comprises an aperture through which the flexible tension member extends.
5 . The surgical tool of claim 1 , wherein the instrument shaft is configurable to accommodate insertion of the actuation rod assembly and the flexible tension member into the lumen.
6 . The surgical tool of claim 5 , wherein the actuation rod assembly comprises a first guide feature that protrudes in a first direction and a second guide feature protrudes in a second direction different than the first direction.
7 . The surgical tool of claim 1 , wherein:
the flexible tension member comprises a drive band; and
the drive band comprises a slot through which a portion of the actuation rod assembly extends.
8 . The surgical tool of claim 7 , wherein the instrument shaft assembly comprises:
a support frame having an aperture through which the portion of the actuation rod assembly extends; and
a bearing mounted to the support frame and interfaced with the drive band.
9 . The surgical tool of claim 7 , wherein the actuation rod assembly comprises a drive band guide aperture through which the drive band extends.
10 . The surgical tool of claim 1 , wherein the flexible tension member comprises first and second portions and wherein the rotatable element is configured to rotate to advance the first portion of the flexible tension member in a first direction and the second portion of the flexible tension member in a second direction opposite of the first direction.
11 . The surgical tool of claim 1 , wherein the proximal assembly comprises a chassis.
12 . The surgical tool of claim 11 , wherein the actuation mechanism is supported by the chassis.
13 . The surgical tool of claim 11 , wherein the instrument shaft is rotatably coupled to the chassis.
14 . A surgical tool comprising:
a proximal actuation assembly;
an end effector;
an instrument shaft that defines a lumen; and
an actuation rod that extends within the lumen, wherein the instrument shaft supports the end effector, and wherein the actuation rod is drivingly coupled with the end effector,
wherein the proximal actuation assembly is operable to rotate the instrument shaft relative to a proximal chassis supporting the instrument shaft and the actuation rod is constrained to rotate with the instrument shaft;
a flexible tension member drivingly coupling the actuation rod to the proximal actuation assembly; and
an isolation tube within the instrument shaft, wherein the flexible tension member extends through the isolation tube such that the isolation tube isolates the flexible tension member from a region of the lumen surrounding the isolation tube, wherein the proximal actuation assembly comprises a proximal rotatable element and the flexible tension member comprises first and second portions extending distally from the rotatable element through the isolation tube within the instrument shaft.
15 . The surgical tool of claim 14 , further comprising a distal rotatable element disposed within the instrument shaft, wherein the first and second portions of the flexible tension member extend distally from the isolation tube to the distal rotatable element.
16 . The surgical tool of claim 14 , wherein the proximal actuation assembly is operable to increase tension in the flexible tension member to move the actuation rod toward the end effector to actuate the end effector.
17 . The surgical tool of claim 14 , wherein the proximal actuation assembly is operable to increase tension in the flexible tension member to move the actuation rod away from the end effector.