Retractable Endoscopic Cutting Blade for Tissue Safety
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Solution Overview
Problem
Existing endoscopic surgical instruments for carpal tunnel or pulley release surgery have a cutting blade that is always protruding through the cannula slot, leading to unintended cutting of tissues during the procedure.
Innovation Solution
An endoscopic surgical instrument with a retractable cutting blade that can be selectively projected or retracted through an axially-extending slot in the cannula, featuring a spring-biased blade assembly and a locking mechanism to prevent accidental blade projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cutting blade is always protruding through the cannula slot, then the blade is readily available for cutting, but unintended cutting of tissues occurs during the procedure
Solution Approach 1:
The cutting blade is designed to be retractable rather than fixed, allowing it to dynamically change position between protruding (ready for cutting) and retracted (safe) states. The blade can be selectively advanced or retracted based on surgical needs, transforming a static configuration into a controllable dynamic system that resolves the contradiction between readiness and safety.
Solution Approach 2:
A locking mechanism acts as an intermediary between the blade and the cannula, controlling blade movement. This intermediary component prevents unintended blade projection while allowing deliberate cutting actions, mediating between the conflicting requirements of blade availability and tissue protection.
2Object-affected harmful factors
If the cutting blade is retractable, then unintended cutting is prevented, but device complexity increases due to spring-biased assembly and locking mechanism
Solution Approach 1:
The spring-biased assembly provides self-service by automatically returning the blade to its retracted position after cutting, eliminating the need for manual retraction. The locking mechanism similarly serves itself by maintaining blade position without continuous external control, reducing operational complexity despite increased structural components.
Solution Approach 2:
The cutting blade, spring mechanism, and locking system are merged into a single integrated assembly that fits within the existing cannula structure. This consolidation combines multiple functions (cutting, retracting, locking) into one unified component system, reducing overall device complexity compared to separate independent mechanisms.
3Manufacturing precision
If the cutting blade is always protruding, then cutting precision is maintained, but safety is compromised due to accidental tissue cutting
Solution Approach 1:
The blade transitions from a static always-protruding state to a dynamic controlled-state system. By allowing the blade to be selectively positioned, the system maintains cutting precision when needed while enhancing safety through controlled retraction, resolving the contradiction between precision and reliability.
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 retractable cutting blade design allows for precise control over tissue cutting, reducing the risk of unintended cutting and enhancing the surgeon's ability to perform complex soft tissue release surgeries with improved precision and safety.
Implementation Method 1
a spring-biased blade assembly
Data Source
AI summary
An endoscopic surgical instrument includes a main body assembly, and a cannula having a lumen and formed with a slot. An inner tube, which houses a spring-biased retractable cutting blade assembly having a cutting blade, is mounted on one end of the main body assembly and extends axially therefrom. The tube is receivable within the lumen of the cannula, and may be particularly oriented within the cannula lumen such that the cutting blade may be caused to project from both the tube and the cannula slot. The inner tube has a bore in which the distal end of an endoscope may be received. The instrument may be locked in one position to allow the endoscope to engage the blade assembly and cause the cutting blade to project from the cannula slot during a tissue cutting procedure, or may be locked in another position wherein the cutting blade remains retracted.An endoscopic surgical instrument includes a front slide, a scope coupler mounted on the front slide, a hammer pivotally mounted on the front slide, a cannula having a lumen and formed with a slot, a sleeve mounted to partially rotate on a portion of the cannula, a blade tube and a retractable cutting blade assembly having a cutting blade situated within the blade tube. The blade tube extends axially from the front slide. The tube is received by the lumen of the cannula. The blade tube has a bore in which the distal end of an endoscope may be received. The instrument may be locked in one position to allow the tip of the endoscope to engage the blade assembly and cause the cutting blade to project from the cannula slot during a tissue cutting procedure, or may be locked in another position wherein the cutting blade remains retracted.