Surgical Cannula with Shape Memory Alloy Fins
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Solution Overview
Problem
Traditional minimally-invasive arthroscopic surgeries face challenges with cannula devices that require longer lengths to penetrate thicker tissues, limiting the working angle due to increased length, and existing annular seals fail to maintain fluid retention effectively during surgical procedures.
Innovation Solution
A surgical portal device with flexible, semi-rigid fins that can be biased outwardly to compress tissue and maintain a seal, utilizing shape memory alloys for enhanced outward bias pressure and fluid retention, and a trocar device to deploy and retract the fins for minimal tissue damage and efficient fluid management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the cannula length is increased to penetrate thicker tissues, then the penetration capability is improved, but the working angle of surgical tools is reduced
Solution Approach 1:
The cannula is segmented into multiple expandable sections or lobes that can be compressed during insertion and expanded at the target site. This allows the cannula to effectively penetrate thick tissue when compressed while maintaining a short effective length when expanded, thereby preserving the working angle for surgical tools.
Solution Approach 2:
The cannula employs a nested structure where inner cannula sections can be telescoped within outer sections during insertion, allowing the device to pass through thick tissue in a compact state and then expand to its full functional length at the surgical site, maintaining optimal working angles.
2Ease of operation
If the cannula inner diameter is increased to improve the working angle, then the working angle is improved, but the portal size becomes equivalent to a large incision
Solution Approach 1:
The cannula employs dynamic, expandable walls that can transition between a compressed low-profile state for insertion and an expanded state at the surgical site. This allows the portal to maintain a small effective size during insertion while providing sufficient working angle when expanded at the target location.
Solution Approach 2:
The cannula utilizes flexible, thin-walled structures that can be compressed to a small diameter for insertion through minimal incisions and then expanded at the surgical site to provide adequate working angle without requiring a permanently large portal opening.
3Reliability
If annular seals are used to prevent fluid leakage, then fluid retention is improved, but leakage occurs during instrument manipulation
Solution Approach 1:
The seal employs flexible, thin-walled structures that can dynamically conform to the shapes of different surgical instruments as they pass through or are manipulated within the cannula. This maintains fluid retention while accommodating instrument movement without leakage.
Solution Approach 2:
The sealing mechanism is dynamic rather than static, allowing the seal to adapt its shape and position in response to instrument manipulation. This enables the seal to maintain fluid retention while flexing to accommodate the passage and movement of various surgical tools.
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 allows for a shorter cannula length, improving the working angle and reducing tissue trauma while maintaining effective fluid retention, enabling more precise and minimally invasive surgical procedures with reduced leakage.
Implementation Method 1
utilizing shape memory alloys for enhanced outward bias pressure and fluid retention
Data Source
AI summary
Surgical device deployment apparatuses that include a cannula having a shaft with an exterior surface, and an interior surface forming a lumen within said cannula, the shaft having a distal portion with a plurality of apertures. An obturator configured to be used in conjunction with the aforementioned cannula has an obturator shaft with a distal portion having a reduced diameter, wherein said obturator shaft is insertable into said lumen of said cannula. In other embodiments, a surgical device deployment tool comprises a handle member with a shaft attached to a distal end of said handle member, said shaft extending distally and terminating at a shaft head. A hollow hood is attached to said shaft head, said hood having an inner surface formed such that a gap exists between said inner surface and an adjacent outside surface of said shaft head.