Tissue Resecting Instrument With Inner Shaft Rotation Lock
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Solution Overview
Problem
Existing tissue resection instruments lack a reliable mechanism to securely lock and unlock the rotation of the inner cutting shaft relative to the outer shaft, which is crucial for precise tissue cutting and efficient fluid management during endoscopic procedures.
Innovation Solution
The tissue resecting instrument features an end effector assembly with a proximal hub housing, retainer cap, elongated outer shaft, and an inner core drive assembly that includes a proximal and distal driver, allowing for rotational locking and unlocking of the inner cutting shaft through a slidable proximal driver mechanism, facilitated by a biasing member and engagement with a retainer cap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotational locking mechanism is added to secure the inner cutting shaft, then reliability of tissue cutting is improved, but device complexity increases
Solution Approach 1:
The proximal driver is designed to be slidable along the inner cutting shaft, transitioning between a proximal position that engages the retainer cap for rotational locking and a distal position that disengages for rotational freedom. This dynamic positioning allows a single component to provide both locking and unlocking functions without requiring separate mechanisms.
Solution Approach 2:
The rotational locking function is segmented into discrete positions: locked position where the proximal driver engages the retainer cap, and unlocked position where it disengages. The biasing member creates distinct stable positions, allowing the system to maintain reliability during cutting while enabling complexity reduction through clear functional separation.
2Manufacturing precision
If the inner cutting shaft is locked in position, then precision of tissue cutting is improved, but ease of operation deteriorates due to additional locking/unlocking steps
Solution Approach 1:
The biasing member automatically pushes the proximal driver toward the proximal locked position, eliminating the need for manual intervention to maintain locking. The system self-locks when the proximal driver engages the retainer cap, and self-unlocks when moved distally, reducing operational steps while maintaining precision.
Solution Approach 2:
The dynamic slidable design allows the proximal driver to transition between locked and unlocked states based on operational needs. During tissue cutting, the locked position provides precision, while during repositioning, the unlocked position provides ease of operation, with the biasing member ensuring automatic return to the locked state.
3Ease of operation
If a slidable driver mechanism is used for rotational control, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The proximal driver serves multiple functions: it acts as a rotational lock when engaged with the retainer cap, serves as a rotational transmission element when disengaged, and is positioned and biased by the biasing member. This multi-functionality reduces the need for separate components, managing complexity while improving ease of operation.
Solution Approach 2:
The proximal driver is nested within the inner cutting shaft and interacts with the retainer cap through a compact engagement interface. The biasing member is nested within the driver assembly, creating a compact integrated mechanism that provides ease of operation without proportionally increasing device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design ensures precise control over the inner cutting shaft's rotation, enabling effective tissue cutting and efficient fluid management by maintaining a locked position during engagement and unlocking for operation, enhancing the instrument's functionality and usability.
Implementation Method 1
The inner core drive assembly further includes a biasing member configured to bias the proximal driver towards the more-proximal position
Data Source
AI summary
A tissue resecting instrument includes an end effector assembly having a proximal hub housing, a retainer cap extending proximally therefrom, an elongated outer shaft extending distally from the proximal hub housing, an inner cutting shaft rotatably disposed within the elongated outer shaft, and an inner core drive assembly that includes a proximal driver and a distal driver. The distal driver is coupled to the inner cutting shaft such that rotation of the distal driver rotates the inner cutting shaft relative to the elongated outer shaft. The proximal driver is slidable relative to the distal drive between a more-proximal position wherein the proximal driver is engaged with the retainer cap to rotationally fix the proximal driver, thereby rotationally locking the inner cutting shaft, and a more-distal position wherein the proximal driver is disengaged from the retainer cap permitting rotation thereof thereby permitting rotation of the inner cutting shaft.