Surgical device actuated using asymmetric spring system
Inventors
Prisco, Giuseppe M. • Duval, Eugene F. • Rogers, Theodore W.
Assignees
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Publication Number
US-11523732-B2
Publication Date
2022-12-13
Expiration Date
Abstract
A compliant surgical device such as a flexible entry guide employs tendons to operate or steer the device and attaches asymmetric or constant force spring systems to control tension in the tendons. As a result, the surgical device can be compliant and respond to external forces during a surgical procedure without rapidly springing back or otherwise causing a reaction that damages tissue. The compliance also permits manual positioning or shaping of the device during or before insertion for a surgical procedure without damaging the tendons or connections of the tendons within the device or to a backend mechanism.
Core Innovation
The invention relates to a surgical device having a shaft including a movable portion and a tendon extending through the shaft, where a tendon is attached to the movable portion and interacts with an asymmetric spring system. The asymmetric spring system has a first end and a second end, with the first end attached to the first end of the tendon, so that the force applied through the tendon to the movable portion has greater dependence on the location of the second end of the asymmetric spring system than on the location of the first end.
The device further includes a mechanism connected to control or move the location of the second end of the asymmetric spring system. By moving the second end, the device changes the magnitude of a force applied through the tendon and thereby moves the movable portion of the shaft. In dependent embodiments, the asymmetric spring system includes a cam attached between a spring element and the tendon, and the cam and spring element are arranged so that force changes less over a range of motion than the spring element force applied to the cam.
The disclosed architecture supports compliant behavior for manual or robotic positioning through compliant flexible surgical entry guides with tendons, while maintaining nearly non-spring-back behavior and reducing reaction forces that could damage tissue. The disclosed embodiments can include sensing and a control system that actuates the mechanism until a sensor in the shaft indicates the shaft reaches a desired configuration, and can include additional tendon and asymmetric spring systems for tendon equilibrium of articulated links.
Claims Coverage
The partial content provides two independent claims that center on a tendon-driven movable shaft portion combined with an asymmetric spring system whose applied force depends more on the location of a spring second end than on a spring first end, and a mechanism that controls or moves that second end to change the force magnitude and move the shaft.
Asymmetric spring system with location-dependent tendon force
A first asymmetric spring system configured such that a force applied by the first asymmetric spring system to the first tendon has greater dependence on a location of the second end of the first asymmetric spring system than on a location of the first end of the first asymmetric spring system.
Mechanism controlling the second end to change force magnitude and move the movable portion
A first mechanism connected to control the location of the second end of the first asymmetric spring system.
Tendon routed through the shaft to a movable portion
A first tendon extending through the shaft and having a second end attached to the movable portion of the shaft.
Location-dependent force through tendon applied to the movable portion
The first asymmetric spring system configured to apply a first force through the first tendon to the movable portion of the shaft, wherein the first force has greater dependence on a location of the second end of the first asymmetric spring system than on a location of the first end of the first asymmetric spring system.
Mechanism moving the second end to change force magnitude and move the movable portion
A first mechanism connected to move the second end of the first asymmetric spring system so that a magnitude of the first force changes and the movable portion of the shaft moves.
Across both independent claims, the core claim coverage is the combination of a tendon attached to a movable shaft portion with an asymmetric spring system whose tendon force depends more on the location of the asymmetric spring second end than on the first end, and a mechanism connected to control or move that second end so the force magnitude changes and the movable shaft portion moves.
Stated Advantages
Reduces reaction forces that could damage tissue while maintaining nearly non-spring-back behavior.
Enables compliant flexible surgical entry guides actuated by tendons while keeping the tendon behavior nearly non-spring-back.
Documented Applications
Compliant flexible surgical entry guides for robotic/computer-assisted steering and manual positioning/reshaping of an articulated shaft using tendon actuation.
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