Arthroscopic Resection Probe Electrode Assembly for Low-Profile Ablation
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Solution Overview
Problem
Existing combination electrosurgical and mechanical resection devices face challenges in securing a reliable electrosurgical assembly with minimal profile size without compromising the function of both mechanical cutting and electrosurgical treatment, and in managing fluid temperatures during use.
Innovation Solution
A combination tissue resecting probe with a stationary outer sleeve and rotating inner shaft, featuring a dielectric spacer to isolate the active electrode, a bypass aspiration pathway to regulate fluid temperature, and a balanced aspiration system to maintain stable plasma formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a resectable portion is added to the distal end of the probe to enable bone tissue resection, then resection capability is improved, but the probe diameter increases and may no longer pass through small arthroscopic portals
Solution Approach 1:
The resectable portion is configured to be received within a portion of the probe shaft, allowing the cutting element to be stored inside the probe body when not in use. This nesting arrangement enables the probe to maintain a small diameter for portal insertion while carrying a functional resection element that can be deployed when needed.
Solution Approach 2:
The probe transitions from a static structure to a dynamic one where the resectable portion can be moved between a stored position within the probe shaft and an extended position for resection. This dynamic configuration allows the probe to adapt its form factor based on operational requirements.
2Ease of operation
If the probe shaft is made flexible to navigate anatomical structures, then ease of insertion is improved, but structural stability and precision control deteriorate
Solution Approach 1:
The probe shaft is divided into multiple segments or sections with different mechanical properties. The proximal portion maintains rigidity for precise control and stable operation, while the distal portion incorporates flexibility to navigate anatomical structures during insertion.
Solution Approach 2:
Different portions of the probe shaft have different mechanical characteristics tailored to their specific functions. The proximal shaft provides structural stability for control, while the distal shaft provides flexibility for navigation, creating local quality variations along the probe length.
3Productivity
If the resectable portion is extended beyond the probe to provide adequate resection surface, then resection effectiveness is improved, but the probe cannot pass through small arthroscopic portals
Solution Approach 1:
The resectable portion is designed to nest within the probe shaft during insertion, concealing its full extent. Once positioned, the resectable portion can be extended or deployed to provide the necessary resection surface area for effective bone tissue removal.
Solution Approach 2:
The probe is inserted first in a compact configuration with the resectable portion stored within the shaft. After successful positioning at the target site, the resectable portion is then deployed or extended to provide adequate resection capability, separating the insertion and resection phases.
Data Source
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AI summary
A combination arthroscopic tissue resecting probe is disclosed, including an elongated shaft with an outer, electrically conductive sleeve and an inner sleeve. Each sleeve has a distal region with a cutting window, the inner sleeve being rotatable to cut tissue. An outer surface of the outer sleeve distal region carries a ceramic body (580) and an electrode (570). The active electrode (570) defining two portions, angularly offset from each other, the two portions including a first portion (571) that extends circumferentially and axially along the tubular distal end and a second portion (578) that extends from a distal end of the first portion and across the tubular distal end, the second portion having at least one flange (595) configured to engage a notch (581) in the electrically insulative spacer (580) to resist separation of the active electrode from the electrically insulative spacer (580). The electrode, the ceramic body and the outer sleeve each define a first aspiration (572, 586, 512) opening for aspirating fluid ablation byproducts therethrough into an interior of the shaft. Various methods of improved electrode attachment are disclosed, that provides a low profile probe distal end, while maintaining electrosurgical functionality.