Needlescopic Scissor End Effector Backlash Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional minimally invasive surgical instruments, such as scissors, suffer from backlash during operation, leading to reduced control and accuracy, and often require multiple exchanges for cutting and cauterization, increasing trauma, recovery time, and the risk of inadvertent tissue penetration. Additionally, existing trocar ports cause significant scarring and trauma due to their size and manipulation requirements.
Innovation Solution
A scissors end effector assembly with a cam tube, clevis, and cam bushing that reduces backlash by using a trigger handle to actuate the shears, allowing for precise control and self-insertion through a small incision, and incorporating electrocautery capabilities for simultaneous cutting and coagulation, minimizing the need for multiple instruments and incisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional scissors are used in minimally invasive surgery, then the instrument can be introduced through a trocar port, but backlash occurs during operation reducing control and accuracy
Solution Approach 1:
The patent replaces the conventional wire-actuated mechanical scissor mechanism with a cam-actuated mechanism. The cam profile converts rotational motion from a cam tube into precise reciprocating motion of the scissor blades, eliminating backlash by maintaining continuous contact between the cam surface and follower. This mechanical substitution provides more reliable and accurate control during surgical operations.
Solution Approach 2:
The patent introduces dynamic elements including a spring-loaded cam mechanism that automatically returns the scissor blades to the open position after cutting. The cam profile is designed to provide controlled motion throughout the entire cycle, from opening to closing and back, enabling precise control and reducing operational errors through continuous, smooth motion rather than rigid wire transmission.
2Adaptability or versatility
If multiple instruments are used for cutting and cauterization, then complete surgical function is achieved, but trauma and recovery time increase
Solution Approach 1:
The patent merges cutting and cauterization functions into a single integrated end effector assembly. The scissor blades are equipped with cutting edges for mechanical cutting and electrocautery elements for thermal coagulation, allowing both functions to be performed with one instrument through a single incision. This reduces the number of instrument exchanges and minimizes tissue trauma compared to using separate instruments.
Solution Approach 2:
The end effector assembly is designed as a universal instrument that performs multiple surgical functions: mechanical cutting via scissor blades, thermal coagulation via electrocautery elements, and tissue manipulation. This multi-functional design eliminates the need for multiple specialized instruments, reducing the cumulative trauma from multiple incisions and instrument exchanges while maintaining complete surgical functionality.
3Adaptability or versatility
If multiple instrument exchanges are performed, then different surgical functions can be performed, but surgery time increases
Solution Approach 1:
The patent combines multiple surgical functions into a single end effector assembly that can perform cutting, coagulation, and tissue manipulation without requiring instrument exchange. The integrated design allows the surgeon to switch between functions using control mechanisms at the proximal end, eliminating the time-consuming process of removing and reinserting multiple instruments during the surgical procedure.
Solution Approach 2:
The patent employs dynamic control mechanisms including spring-loaded return mechanisms and cam-actuated motion that allow rapid switching between different surgical functions. The end effector can transition from cutting mode to coagulation mode and vice versa through controlled actuation, significantly reducing the time required compared to physically exchanging instruments while maintaining full functional versatility.
4Ease of operation
If conventional trocars are used for instrument insertion, then instruments can be introduced into the body cavity, but significant scarring and trauma occur
Solution Approach 1:
The patent replaces the traditional trocar mechanism with a needle-tip insertion system. Instead of using a rigid trocar that requires forceful insertion through fascia and muscle layers, the flexible needle tip can be gently advanced through tissue, creating a smaller incision that causes minimal trauma and scarring while still providing adequate access for the end effector assembly.
Solution Approach 2:
The patent uses a flexible needle tip and thin-walled cannula structure that can be gently inserted through tissue layers without requiring the forceful manipulation needed for conventional trocars. This flexible insertion approach creates a smaller, less traumatic incision that heals with minimal scarring while maintaining instrument accessibility and functional versatility.
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 enhances surgical precision, reduces trauma and scarring, shortens surgery time, and improves safety by eliminating backlash and allowing for single-step cutting and coagulation, while reducing the number of incisions and instrument exchanges.
Implementation Method 1
a cam bushing (160) with a cam profile that converts the rotational motion of the cam tube (180) into reciprocating linear motion of the shears (120, 130)
Implementation Method 2
an electrocautery element (290) that can be used to coagulate and seal the tissue at the site of the cut
Data Source
AI summary
A needlescopic scissors end effector assembly includes a pair of jaws or blades pivotable to perform a cutting or shearing operation. The scissors end effector assembly includes a cannula having a diameter between about 1 mm to 5 mm and a needle tip configured for percutaneous operation. The pair of jaws or blades includes cam profile surfaces to interact with an opening defined with the needle tip to actuate opening and closing of the pair of jaws or blades and to prevent backlash effect during the opening and closing of the pair of jaws or blades.