Shape Memory Surgical Clip with Thermoelectric Actuation
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Solution Overview
Problem
Existing surgical clips and manipulators face challenges in achieving reliable haemostasis in hollow tubular organs without causing trauma, maintaining blood flow, and facilitating easy removal and reapplication, due to limitations in shape memory alloys, invasiveness, and trauma risks during procedures.
Innovation Solution
A surgical clip made of a shape memory alloy with a nitinol ear, coupled with a thermoelectric transducer, allows for controlled heating and cooling to close and open the clip, enabling secure haemostasis and blood flow restoration, while minimizing trauma and simplifying the surgical process through a single device for delivery, manipulation, and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a chilled sterile clip is set within the lumen and heated to close jaws for haemostasis, then reliable haemostasis is achieved, but blood flow cannot be restored and the vessel remains permanently closed
Solution Approach 1:
The clip transitions from a static permanent closure state to a dynamic reversible state by utilizing temperature-dependent shape memory effects. The clip can be heated to close jaws for haemostasis, then cooled to reopen jaws and restore blood flow, making the closure temporary and controllable rather than permanent.
Solution Approach 2:
The clip's physical state is changed by varying temperature parameters. At elevated temperatures (above transformation temperature), the shape memory alloy returns to its memorized closed shape for haemostasis. At lower temperatures (below transformation temperature), the clip becomes soft and pliable, allowing jaw reopening and blood flow restoration.
2Reliability
If a clip with pointed end is used to stitch and fixate tissue, then secure fixation is achieved, but tissue piercing and trauma occur which is unacceptable for thin vessels
Solution Approach 1:
The clip design differentiates between the engagement mechanism (jaws with serrations or barbs that grip tissue locally without piercing) and the delivery mechanism (rounded tip instead of pointed end). This local quality change allows secure fixation through gripping surfaces rather than invasive piercing, reducing trauma to thin vessels.
Solution Approach 2:
The traditional mechanical piercing fixation method is replaced with a thermal-actuated shape memory system. The clip is delivered in an open state at low temperature, then heated to close jaws that grip the tissue through friction and mechanical interlocking features, eliminating the need for pointed piercing while maintaining secure fixation.
3Reliability
If multiple devices are used for clip delivery, manipulation, and removal, then each function can be optimized, but device complexity and procedural time increase
Solution Approach 1:
A single manipulator device integrates multiple functions: it can deliver the clip in an open state, manipulate the clip during positioning, and remove the clip after use. The manipulator includes features like a gripping mechanism for the clip's ear, heating/cooling capability via thermoelectric transducer, and release mechanisms, allowing one device to perform what previously required multiple specialized tools.
Solution Approach 2:
The functions of separate delivery, manipulation, and removal devices are merged into a single integrated manipulator. The manipulator combines the delivery catheter, heating/cooling elements, gripping mechanisms, and release features into one unified tool, reducing procedural complexity and the number of instrument exchanges required during surgery.
4Ease of operation
If the clip is removed by cooling below body temperature, then the clip opens and can be removed, but serious consequences or difficulty in implementation occur
Solution Approach 1:
A thermoelectric transducer serves as an intermediary device that enables controlled temperature changes in the clip without requiring bulk cooling of the surrounding tissue. The transducer can be activated to cool the clip locally for removal, then deactivated and reversed to heat the clip back to body temperature, avoiding the harmful effects of prolonged tissue cooling while maintaining easy clip removal capability.
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 solution provides reliable haemostasis, reduces trauma, and simplifies surgical procedures by allowing for easy opening and closing of the clip to restore blood flow, using a single device for clip delivery, manipulation, and removal, enhancing surgical efficiency and accuracy.
Implementation Method 1
at least the base portion is formed of a shape memory alloy having a transformation temperature and tending to force the first and second arms toward each other when a temperature of the base portion meets or exceeds the transformation temperature of the base portion
Implementation Method 2
A surgical clip made of a shape memory alloy with a nitinol ear, coupled with a thermoelectric transducer, allows for controlled heating and cooling to close and open the clip
Implementation Method 3
A surgical clip made of a shape memory alloy with a nitinol ear, coupled with a thermoelectric transducer, allows for controlled heating and cooling to close and open the clip
Data Source
AI summary
Some embodiments relate to a clip comprising: a base portion; first and second opposed arms coupled to the base portion; and first and second opposed jaws coupled to the respective first and second arms, the first and second opposed jaws each having an inwardly extending portion that extends towards the base portion; wherein at least the base portion is formed of a shape memory alloy tending to force the first and second arms toward each other when a temperature of the base portion meets or exceeds a transformation temperature of the base portion.