Tissue Resection Shaft Locking for Precise Cutting and Fluid Flow
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Solution Overview
Problem
Existing tissue resection instruments face challenges in efficiently resecting and removing tissue from internal surgical sites, particularly within organs like the uterus, due to limitations in distending and maintaining a clear working space, and in managing fluid inflow and outflow during procedures.
Innovation Solution
A tissue resecting instrument with an end effector assembly featuring a rotatable inner shaft within an outer shaft, a hub housing, a retainer cap, and an RFID chip, allowing for controlled tissue cutting and fluid management through a snap-fit engagement and biasing spring mechanism, enabling rotational locking and unlocking of the inner shaft relative to the outer shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an end effector assembly with rotatable inner shaft is used for tissue resection, then tissue cutting precision is improved, but device complexity increases due to multiple shafts and locking mechanisms
Solution Approach 1:
The inner shaft is rotatably disposed within the outer shaft, creating a nested configuration where one component is housed inside another. This nesting arrangement enables the rotatable cutting mechanism while minimizing the overall device footprint and reducing structural complexity despite the advanced functionality.
Solution Approach 2:
The inner shaft is designed to be rotatable relative to the outer shaft, transitioning between locked and unlocked states. This dynamic capability allows the device to switch between stable transport mode and active cutting mode, providing precision when needed while maintaining operational simplicity through mechanical state transitions.
2Reliability
If a retainer cap with snap-fit engagement is used to lock the proximal driver, then reliability of the locking mechanism is improved, but ease of manufacture decreases due to additional assembly steps
Solution Approach 1:
The retainer cap is designed as a separate, modular component that can be independently manufactured and then assembled to the proximal driver. This segmentation allows for specialized manufacturing of the cap with precise snap-fit features while keeping the main driver assembly simpler, ultimately improving reliability without prohibitive manufacturing complexity.
Solution Approach 2:
The snap-fit engagement mechanism replaces more complex mechanical locking systems such as threaded fasteners or multi-component clamps. The snap-fit provides reliable locking through elastic deformation and geometric interlocking, achieving high reliability with a simpler, more manufacturable solution.
3Adaptability or versatility
If an RFID chip is integrated into the retainer cap pocket, then adaptability for tracking and identification is improved, but device complexity increases due to additional components
Solution Approach 1:
The retainer cap is designed with dual functionality: it provides mechanical locking through snap-fit engagement and simultaneously serves as a housing for the RFID chip. This multi-functionality integrates tracking and identification capabilities into an existing component, adding adaptability without proportionally increasing overall device complexity.
Solution Approach 2:
The RFID chip provides a digital copy or representation of the physical device's identity and status information. This electronic tagging system enables tracking and identification without requiring additional physical markers or complex mechanical identification mechanisms, adding versatility with minimal structural complexity.
4Reliability
If a biasing spring is used to bias the proximal driver towards locked position, then reliability of the locked state is improved, but ease of operation decreases due to force required to unlock
Solution Approach 1:
The biasing spring applies a preliminary force that pre-loads the locking mechanism into the locked position, ensuring reliable engagement before operation begins. This preliminary anti-action counteracts any tendency toward disengagement, providing dependable locking while the spring's elastic nature allows controlled override when unlocking is intentionally initiated.
Solution Approach 2:
The biasing spring creates a dynamic system where the proximal driver can exist in two stable states: locked (spring compressed) and unlocked (spring extended). This dynamic design provides reliable locking through spring force while allowing easy transition between states through simple actuation, balancing reliability with operational ease.
Data Source
AI summary
A tissue-resecting end effector assembly includes an outer shaft having a hub housing disposed about a proximal end portion thereof, an inner shaft rotatably disposed within the outer shaft and having a distal driver disposed about a proximal end portion thereof, a proximal driver, a retainer cap, and an RFID chip. The proximal driver is slidably coupled to the distal driver in fixed rotational orientation. The retainer cap is fixedly engaged with the hub housing, thereby fixing the retainer cap relative to the hub housing and the outer shaft. The retainer cap is configured to selectively lock the proximal driver in fixed rotational orientation, thereby selectively locking the inner shaft relative to the outer shaft. The RFID chip is disposed within a pocket of the retainer cap that is closed upon engagement of the retainer cap with the hub housing, thereby retaining the RFID chip therein.