Curved Needle Delivery via Shape Memory Alloy Transition
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Solution Overview
Problem
In endoscopic surgical suturing, particularly during natural orifice transenteric surgery, curved needles face challenges in being delivered through narrow channels due to their size and cause tissue shifting during puncture, making precise suturing difficult.
Innovation Solution
A needle delivery device comprising a shape memory alloy needle and a guide system with a suturing guide and positioning member that stabilizes tissue and allows the needle to transition from a constrained to an unconstrained configuration, enabling precise puncture and suturing without tissue displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If curved needles are used for surgical suturing, then suturing precision and tissue approximation quality are improved, but the needle cannot pass through narrow canula or endoscope working channels
Solution Approach 1:
The curved needle is segmented into multiple straight segments that can be sequentially assembled or deployed within the narrow channel. This allows the needle to pass through the channel in a compact form and then be configured into its curved shape at the target site for precise suturing.
Solution Approach 2:
The needle delivery system employs a dynamic configuration mechanism that allows the needle to transition from a straight, compact state during delivery to a curved, functional state at the surgical site. This dynamic transformation enables the needle to satisfy both the space constraint during delivery and the functional requirement for precise suturing.
2Ease of operation
If curved needles are forced through narrow channels, then needle delivery is achieved, but tissue shifting and displacement occur during puncture
Solution Approach 1:
A guide catheter or delivery sheath is introduced as an intermediary device that maintains the needle in a constrained, straight configuration during passage through the channel. The guide catheter prevents premature needle curvature and tissue interaction, ensuring the needle remains positioned accurately until it reaches the target site for puncture.
Solution Approach 2:
The needle is pre-loaded and pre-positioned within the delivery system in a controlled, straight configuration before reaching the target site. This preliminary preparation ensures that the needle maintains its intended trajectory and positioning accuracy during delivery, preventing tissue shifting and ensuring precise puncture site placement.
3Ease of operation
If straight needles are used to pass through narrow channels, then needle delivery is achieved, but suturing quality and tissue approximation are reduced
Solution Approach 1:
The needle system employs dynamic configurability, transitioning from a straight delivery state to a curved functional state. This allows the needle to be delivered through narrow channels in a straight configuration while then being deployed into a curved shape at the surgical site to achieve high-quality suturing and tissue approximation.
Solution Approach 2:
The needle's geometric parameters are changed from a straight configuration during delivery to a curved configuration during suturing. This parameter transformation enables the needle to satisfy the space constraints of narrow delivery channels while maintaining the curved geometry necessary for precise tissue approximation and high-quality suturing.
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
Enables the precise delivery and use of curved needles through narrow channels, stabilizing tissue during suturing and maintaining the accuracy of puncture sites, thereby improving the efficacy of endoscopic suturing procedures.
Implementation Method 1
alloys that display a shape memory effect, such as those having approximately 50 atomic % nickel (Ni) and 50 atomic % titanium (Ti), are now widely used. The shape memory effect is arises due to a phase change that takes place in certain alloys as they are cooled or heated through their characteristic transformation temperature.
Implementation Method 2
The best known shape memory alloys are Ni—Ti (Nitinol) alloys in which the phase change is from an ordered cubic crystal form above the transformation temperature to a crystalline phase below the transformation temperature. The transformation is known as a martensitic transformation between a high temperature 'austenitic' form and a low temperature 'martensitic' form.
Data Source
AI summary
A needle delivery device is described and includes generally, a needle made of a shape memory alloy pre-formed in an unconstrained configuration, such as, for example, an arc or a curved needle. The needle delivery device also includes a needle delivery guide, a suturing guide and a positioning member. The needle has an eye at its leading tip for holding suture material. The needle delivery guide has a needle channel for passage of the needle therethrough. The needle channel is configured to hold the needle in a constrained configuration, for example, in substantial alignment with the longitudinal axis of the needle channel. The suturing guide is pivotally connected to the delivery guide. The positioning member moves the suturing guide between an extended position and a collapsed position, wherein, in the extended position, the suturing guide is configured to stabilize the tissue and guide the needle in its unconstrained configuration and to enable access by, for example, a grasper or other tool, to the suture material.