Rotary input for lever actuation

A surgical instrument includes a surgical end effector coupled to an elongate tube and a rod that passes through the elongate tube. A control mechanism coupled to the elongate tube includes an input axle having a first axis of rotation, an idler pulley having a second axis of rotation perpendicular to the first axis, and a lever coupled to the rod and having a third axis of rotation parallel to the second axis. First and second capstans are fixed to the input axle. Cables pass over the idler pulley and are coupled to the lever. Rotating the input axle in a first direction winds a first cable onto the first capstan, rotates the lever, and moves the rod in a second direction. Rotating the input axle opposite the first direction winds a second cable onto the second capstan, rotates the lever, and moves the rod opposite the second direction.

BACKGROUND

Field

Embodiments of the invention relate to the field of force transmissions; and more specifically, to force transmissions for use in surgical instruments intended for use in teleoperated minimally invasive surgeries.

Background

Minimally invasive surgery (MIS) (e.g., endoscopy, laparoscopy, thoracoscopy, cystoscopy, and the like) allows a patient to be operated upon through small incisions by using elongated surgical instruments introduced to an internal surgical site. Generally, a cannula is inserted through the incision to provide an access port for the surgical instruments. The surgical site often comprises a body cavity, such as the patient's abdomen. The body cavity may optionally be distended using a clear fluid such as an insufflation gas. In traditional minimally invasive surgery, the surgeon manipulates the tissues by using hand-actuated end effectors of the elongated surgical instruments while viewing the surgical site on a video monitor. In teleoperated minimally invasive surgery, the surgeon manipulates the tissues by using mechanically actuated end effectors of the elongated surgical instruments. Mechanical actuation may allow for improved control of the surgical instruments.

The mechanically actuated surgical instruments will generally have an end effector in the form of a surgical tool such as a forceps, a scissors, a clamp, a needle grasper, or the like at a distal end of an elongate tube. A flexible rod may extend from the end effector to a proximal control mechanism that pushes and pulls the rod to provide an actuating force to open and close the end effector.

Rotary actuators, such as servo motors, are an effective way to provide controlled actuation forces to the proximal control mechanism. The proximal control mechanism then translates the rotary input force into the push-pull motion needed to control the opening and closing of the end effector. The proximal control mechanism may receive many such rotary inputs, perhaps six to eight, each of which can be translated into an appropriate motion for controlling some aspect of the end effector. It is desirable that the proximal control mechanism be compact to avoiding crowding in the surgical field.

In view of the above, it is desirable to provide an improved apparatus and method for transmitting rotary actuating forces to a push-pull rod in an elongate tube of a surgical instrument intended for use in teleoperated minimally invasive surgeries.

SUMMARY

A mechanically actuated surgical instrument includes a surgical end effector coupled to an elongated tube. A rod is coupled to the surgical end effector and passes through the elongated tube. A proximal control mechanism coupled to the elongated tube includes an input axle having a first axis of rotation, an idler pulley having a second axis of rotation perpendicular to the first axis, and a lever coupled to the rod and having a third axis of rotation substantially parallel to the second axis. First and second capstans are fixed to the input axle. A first cable passes over the idler pulley and is coupled to the lever such that rotating the input axle in a first direction winds the first cable onto the first capstan, rotates the lever, and moves the rod in a second direction. A second cable passes over the idler pulley and is coupled to the lever such that rotating the input axle in a third direction opposite the first direction winds the second cable onto the second capstan, rotates the lever, and moves the rod in a fourth direction opposite the second direction.

DETAILED DESCRIPTION

FIG. 1is a simplified diagrammatic perspective view of a teleoperated surgical system100. The teleoperated surgical system100includes a support assembly110mounted to or near an operating table supporting a patient's body122. The support assembly110supports one or more surgical instruments120that operate on a surgical site within the patient's body122.

The term “instrument” is used herein to describe a device configured to be inserted into a patient's body and used to carry out surgical procedures. The instrument includes a surgical tool, such as a forceps, a needle driver, a shears, a monopolar cauterizer, a bipolar cauterizer, a tissue stabilizer or retractor, a clip applier, an anastomosis device, an imaging device (e.g., an endoscope or ultrasound probe), and the like. Some instruments used with embodiments of the invention further provide an articulated support for the surgical tool so that the position and orientation of the surgical tool can be manipulated.

The simplified perspective view of the teleoperated surgical system100shows only a single surgical instrument120to allow aspects of the invention to be more clearly seen. A functional teleoperated surgical system would further include a vision system that enables the operator to view the surgical site from outside the patient's body122. The vision system can include a video monitor for displaying images received by an optical device provided at a distal end of one of the surgical instruments120. The optical device can include a lens coupled to an optical fiber which carries the detected images to an imaging sensor (e.g., a CCD or CMOS sensor) outside of the patient's body122. Alternatively, the imaging sensor may be provided at the distal end of the surgical instrument120, and the signals produced by the sensor are transmitted along a lead or wirelessly for display on the monitor. An illustrative monitor is the stereoscopic display on the surgeon's cart in the da Vinci® Surgical System, marketed by Intuitive Surgical, Inc., of Sunnyvale Calif.

A functional teleoperated surgical system would further include a control system for controlling the insertion and articulation of the surgical instruments120. This control may be effectuated in a variety of ways, depending on the degree of control desired, the size of the surgical assembly, and other factors. In some embodiments, the control system includes one or more manually operated input devices, such as a joystick, exoskeletal glove, or the like. These input devices control motors, such as servo motors, which, in turn, control the articulation of the surgical assembly. The forces generated by the motors are transferred via drivetrain mechanisms, which transmit the forces from the motors generated outside the patient's body122through an intermediate portion of the elongate surgical instrument120to a portion of the surgical instrument inside the patient's body122distal from the motor. Persons familiar with telemanipulative, teleoperative, and telepresence surgery will know of systems such as the da Vinci® Surgical System and the Zeus® system originally manufactured by Computer Motion, Inc. and various illustrative components of such systems.

The surgical instrument120is shown inserted through an entry guide124, e.g., a cannula in the patient's abdomen. A functional teleoperated surgical system may provide an entry guide manipulator (not shown; in one illustrative aspect the entry guide manipulator is part of the support assembly110) and an instrument manipulator (discussed below). The entry guide124is mounted onto the entry guide manipulator, which includes a mechanically actuated positioning system for positioning the distal end of the entry guide124at the desired target surgical site. The mechanically actuated positioning system may be provided in a variety of forms, such as a serial link arm having multiple degrees of freedom (e.g., six degrees of freedom) or a jointed arm that provides a remote center of motion (due to either hardware or software constraints) and which is positioned by one or more unpowered, lockable setup joints mounted onto a base. Alternatively, the entry guide manipulator may be manually maneuvered so as to position the entry guide124in the desired location. In some telesurgical embodiments, the input devices that control the manipulator(s) may be provided at a location remote from the patient (outside the room in which the patient is placed). The input signals from the input devices are then transmitted to the control system, which, in turn, manipulates the instrument manipulators130in response to those signals. The instrument manipulator may be coupled to the entry guide manipulator such that the instrument manipulator130moves in conjunction with the entry guide124.

The surgical instrument120is detachably connected to the mechanically actuated instrument manipulator130. The mechanically actuated manipulator includes a coupler132to transfer controller motion from the mechanically actuated manipulator to the surgical instrument120. The instrument manipulator130may provide a number of controller motions which the surgical instrument120may translate into a variety of movements of the end effector on the surgical instrument such that the input provided by a surgeon through the control system is translated into a corresponding action by the surgical instrument.

FIG. 2is a plan view of an illustrative embodiment of the surgical instrument120, comprising a distal portion250and a proximal control mechanism240coupled by an elongate tube210. The distal portion250of the surgical instrument120may provide any of a variety of surgical devices such as the forceps258shown, a needle driver, a cautery device, a cutting tool, an imaging device (e.g., an endoscope or ultrasound probe), or a combined device that includes a combination of two or more various tools and imaging devices. Surgical devices that provide an opening and closing motion, such as the forceps258shown, may be coupled to a rod that passes through the elongate tube210and into the proximal control mechanism240. The proximal control mechanism translates input from an actuator to push and pull on the rod to open and close the surgical device.

FIG. 3is a top view of the proximal control mechanism240for the surgical instrument ofFIG. 2showing the input connections300that connect to actuators (not shown). The actuators used with embodiments of the invention are rotary actuators, such as servo motors. The proximal control mechanism of the surgical instrument may provide input connections for a number of actuators with each actuator controlling one motion of the surgical tool. For example, the proximal control mechanism240shown provides eight input connections300. Of course, some input connections may be unused by some surgical instruments.

FIG. 4is a side view of the proximal control mechanism240for the surgical instrument ofFIG. 2with portions of the housing and support structure removed to show a mechanism for driving a mechanically actuated surgical instrument. One of the input connections300is fixed to an input axle400having an input axis about which the input connection rotates. The input axle400receives a rotational input from an actuator that is removably coupled to the input connection300. A hand wheel402may be coupled to an opposite end of the input axle400from the coupler.

FIGS. 5A and 5Bare side views of a portion of the surgical instrument ofFIG. 2shown in two operative positions. The portion shown provides a push-pull drive for a rod500that passes through the elongate tube502to open and close the surgical instrument. Note that only the proximal end of the elongate tube502is shown. The portion of the elongate tube that projects toward the surgical site is not shown.

The input axle400has a first axis of rotation along the length of the axle. An input connection300for a rotary actuator may be coupled to an end of the input axle400. A hand wheel402may be coupled to an opposite end of the input axle400from the input connection300. A first capstan504and a second capstan506are fixed to the input axle400. A first cable508passes over an idler pulley516with a first end coupled to the first capstan504and a second end510coupled to a lever518. The idler pulley516has a second axis of rotation substantially perpendicular to the first axis of rotation of the input axle400. The lever518has a third axis of rotation526substantially parallel to the second axis of rotation. In another embodiment shown inFIG. 6, the first capstan604and the second capstan606are portions of a single capstan600.

As shown inFIG. 5A, rotating the input axle400in a first direction520winds the first cable508onto the first capstan504and rotates the lever518in a second direction522. As shown inFIG. 5B, rotating the input axle400in a third direction530opposite the first direction520winds the second cable512onto the second capstan506and rotates the lever518in a fourth direction532opposite the second direction. The first cable508and the second cable512may be portions of a single cable. The lever518is coupled to the rod500by a linkage528to impart a push-pull movement524to the rod and thereby transmit a force that can open and close an end effector at the distal end of the elongate tube502of a mechanically actuated surgical instrument. In an optional embodiment, a spring (not shown) may be placed between the lever and the support structure to counteract friction in the force transmission mechanism and/or to bias the movable end effector component to one position or another (e.g., grip biased open or closed).

The force transmission may use levers in various arrangements. Different classes of levers provide various advantages in terms of layout, force multiplication, and kinematic relationships. For example, the lever518shown inFIGS. 5A and 5Bis a first class lever. The fulcrum (axis of rotation526) is between the applied force510,514and the linkage528that couples the load500to the lever518.

FIG. 6shows a force transmission that uses a second class lever. The linkage628that couples the load500to the lever618is between the applied force510,514and the fulcrum (axis of rotation626).