Coaxial drive

1. A surgical instrument, comprising:

a handle adapted for manipulation by a user to control the surgical instrument;

an elongated shaft extending distally from the handle, the elongated shaft including a proximal portion defining a longitudinal axis and an articulating distal portion pivotally coupled to the proximal portion;

an end effector extending distally from the articulating distal portion of the elongated shaft and defining an end effector axis, the end effector coupled to the articulating distal portion such that the end effector is rotatable about the end effector axis; and

a drive mechanism including at least one actuator disposed on the handle, the at least one actuator operable to move the end effector in at least three independent modes relative to the longitudinal axis or the end effector axis, the at least three modes including:

an articulation mode wherein the articulating distal portion of the elongated shaft pivots relative to the longitudinal axis;

a shoulder roll mode wherein the articulating distal portion of the elongated shaft rotates about the longitudinal axis; and

a wrist roll mode wherein the end effector rotates about the end effector axis,

wherein the drive mechanism is configured to transmit mechanical motion through the elongated shaft in either a longitudinal direction parallel to the longitudinal axis or a rotational direction about the longitudinal axis to induce each of the at least three independent modes, and wherein the drive mechanism includes an articulation spool movable in the longitudinal direction to induce movement of the end effector in the articulation mode and a shoulder roll knob movable in the rotational direction to induce movement of the end effector in the shoulder roll mode, and

wherein a splined slip joint is defined between the articulation spool and the shoulder roll knob such that movement of the shoulder roll knob in the rotational direction imparts a corresponding rotational movement in the articulation spool, and wherein longitudinal movement of the articulation spool is independent of motion in the shoulder roll knob.

2. The instrument according to claim 1 , wherein the drive mechanism further includes a lock to selectively prohibit motion in the articulation and shoulder roll modes.

3. The instrument according to claim 1 , wherein the articulation spool is operatively coupled to a pair of tendons extending to the articulating distal portion of the elongated shaft such that longitudinal movement in the articulation spool induces differential longitudinal motion in the tendons.

4. The instrument according to claim 3 , wherein the pair of tendons is coupled to an articulation member, and wherein longitudinal movement in the articulation spool induces pivotal motion in the articulation member to induce differential longitudinal motion in the tendons.

5. The surgical instrument according to claim 1 , wherein the end effector includes a pair of jaw members, and wherein the least one actuator is operable to move the end effector in an independent clamping mode wherein at least one jaw member is configured to move between an open position substantially spaced from the other of the pair of jaw members and a closed position wherein the jaw members are closer together.

6. The surgical instrument according to claim 5 , wherein the end effector includes a knife blade, and wherein the at least one actuator is operable to move the end effector in a cutting mode wherein the knife blade is moved axially with respect to the end effector axis.

7. The surgical instrument according to claim 6 , wherein the drive mechanism includes a knife lock mechanism configured to prohibit motion in the cutting mode when the at least one jaw member is in the open position and permit motion in the cutting mode when the at least one jaw member is in the closed position.

8. The surgical instrument according to claim 5 , wherein the at least one of the pair of jaw members is coupled to a source of electrical energy.

9. A surgical instrument, comprising:

a handle adapted for manipulation by a user to control the surgical instrument;

an elongated shaft extending distally from the handle, the elongated shaft including a proximal portion defining a longitudinal axis and an articulating distal portion pivotally coupled to the proximal portion;

an end effector extending distally from the articulating distal portion of the elongated shaft and defining an end effector axis, the end effector coupled to the articulating distal portion such that the end effector is rotatable about the end effector axis; and

a drive mechanism including at least one actuator disposed on the handle, the at least one actuator operable to move the end effector in at least three independent modes relative to the longitudinal axis or the end effector axis, the at least three modes including:

an articulation mode wherein the articulating distal portion of the elongated shaft pivots relative to the longitudinal axis;

a shoulder roll mode wherein the articulating distal portion of the elongated shaft rotates about the longitudinal axis; and

a wrist roll mode wherein the end effector rotates about the end effector axis,

wherein the drive mechanism further includes a lock to selectively prohibit motion in the articulation and shoulder roll modes, and wherein the lock includes a locking spool movable in a longitudinal direction parallel to the longitudinal axis between a first position to permit motion in the articulation and shoulder roll modes and a second position to simultaneously prohibit motion in the articulation and shoulder roll modes.

10. The instrument according to claim 9 , wherein the at least one actuator is operable to induce motion in the wrist roll mode when the locking spool is in the second position.

11. The instrument according to claim 9 , wherein the drive mechanism includes a shoulder roll knob movable in a rotational direction about the longitudinal axis to induce movement of the end effector in the shoulder roll mode, and wherein at least one splined slip joint is defined between the locking spool and the shoulder roll knob such that movement of the shoulder roll knob in the rotational direction imparts a corresponding rotational movement in the locking spool, and wherein longitudinal movement of the locking spool is independent of motion in the shoulder roll knob.

12. The instrument according to claim 11 , wherein the locking spool includes a series of radially oriented teeth and detents thereon to provide an indexing mechanism in the shoulder roll mode.