Powered Tissue Resecting Device with Dynamic Seal and Cooling
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Solution Overview
Problem
Existing tissue resection devices face challenges in efficiently resecting tissue while maintaining a clear visual field and managing fluid flow during endoscopic procedures, particularly in distending organs like the uterus, due to friction and heat issues during motor-driven cutting and suction processes.
Innovation Solution
A powered tissue resecting device comprising an end effector assembly with a proximal hub housing, a cutting member, and a handpiece assembly with a drive rotor, seal ring, and heat sink materials, which reduces friction and heat buildup by transitioning a valve between open and closed positions to enhance fluid flow and suction efficiency, and engages bayonet threading for thermal communication to cool the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal ring is used to prevent fluid ingress into the annular space, then fluid sealing is improved, but friction between the seal ring and drive rotor increases
Solution Approach 1:
The seal ring is extracted from continuous contact with the drive rotor during rotation. The hub housing includes a ramp surface that displaces the seal ring from the drive rotor upon engagement, removing the sealing interface from the rotational path to eliminate friction while maintaining sealing when needed
Solution Approach 2:
The seal ring transitions from a static sealing position to a displaced non-contact position during operation. The ramp surface dynamically moves the seal ring away from the drive rotor as the hub engages with the handpiece, adapting the sealing configuration based on operational state
2Productivity
If the drive rotor rotates at high speed to drive the cutting member, then productivity is improved, but heat buildup increases
Solution Approach 1:
The fluid channel acts as an intermediary cooling pathway. Fluid is directed through the hub housing and around the drive rotor, serving as a heat transfer medium that carries away heat generated during high-speed rotation without interfering with the cutting function
Solution Approach 2:
A fluid cooling system is implemented where fluid flows through channels in the hub housing to cool the drive rotor during high-speed operation. The hydraulic/pneumatic flow removes heat efficiently, enabling sustained high-speed cutting
3Stress or pressure
If the valve remains closed to maintain pressure, then fluid containment is improved, but suction efficiency decreases
Solution Approach 1:
The valve operates periodically, transitioning between closed and open states. During tissue resection, the valve opens to allow efficient suction of tissue and fluid through the cutting member, then closes to maintain pressure in the uterine cavity, creating a rhythmic cycle that achieves both objectives
Solution Approach 2:
The valve is opened in advance during the tissue resection phase to prepare for efficient suction. The system anticipates the need for suction and opens the valve before tissue is presented to the cutting member, ensuring immediate and efficient removal of resected tissue
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
The device effectively resects tissue with reduced friction and heat, maintaining a clear visual field and efficient fluid management, allowing for precise and effective tissue removal with enhanced suction force and thermal cooling.
Implementation Method 1
the seal ring is sealingly engaged between the drive casing and the drive rotor to inhibit fluid ingress into the annular space
Implementation Method 2
the handpiece assembly with a drive rotor, seal ring, and heat sink materials, which reduces friction and heat buildup
Data Source
AI summary
A tissue resecting device includes an end effector assembly including a proximal hub housing and a cutting member extending distally from the proximal hub housing, and a handpiece assembly. The handpiece assembly includes a handle housing, a drive casing extending distally from the handle housing, a drive rotor extending through and distally from the drive casing, and a seal ring disposed about the drive rotor. In an at-rest position, the seal ring is sealingly engaged between the drive casing and the drive rotor to inhibit fluid ingress into the annular space. Upon engagement of the end effector assembly with the handpiece assembly, a portion of the proximal hub housing is configured to urge the seal ring from the at-rest position to a displaced position wherein the seal ring is displaced from the drive rotor to reduce friction therebetween upon rotation of the drive rotor relative to the drive casing.