Resorbable Laparoscopic Hemostat via Composite Felt
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Solution Overview
Problem
Existing hemostatic wound dressings based on oxidized cellulose are not suitable for introduction through a trocar during laparoscopic surgical procedures, lacking the necessary properties for effective deployment and hemostasis in minimally invasive surgeries.
Innovation Solution
A resorbable hemostatic nonwoven felt made of three-dimensionally entangled oxidized cellulose fibers with specific mechanical and water absorption properties, manufactured through a process involving minimal twist yarns, scouring, oxidation, pliabilization, de-knitting, carding, and needle-punching, allowing for deployment through a laparoscopic trocar while maintaining structural integrity and hemostatic effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional knitted or non-woven oxidized cellulose hemostats are used, then hemostatic function is provided, but they cannot be introduced through a trocar during laparoscopic procedures due to insufficient mechanical strength and structural integrity
Solution Approach 1:
The patent creates a composite structure by bonding oxidized cellulose fibers to a continuous thermoplastic polymer matrix. This composite approach combines the hemostatic properties of oxidized cellulose with the mechanical strength and flexibility of thermoplastic polymers, enabling the material to withstand insertion forces through a trocar while maintaining its hemostatic function.
Solution Approach 2:
The patent modifies the physical and mechanical parameters of the hemostat by incorporating thermoplastic polymers with specific properties (melting point, flexibility, bond strength). This changes the overall material parameters to achieve both sufficient insertion strength and post-insertion flexibility for proper deployment through the trocar.
2Strength
If the felt is made with higher basis weight to improve structural integrity, then mechanical strength increases, but insertion force through the trocar increases making deployment difficult
Solution Approach 1:
The patent optimizes the basis weight parameter within a specific range (70-200 gsm) and combines it with thermoplastic polymer content (10-50% by weight) to achieve the right balance. The thermoplastic binder provides mechanical reinforcement that allows lower basis weights to achieve sufficient structural integrity without requiring excessive insertion forces.
Solution Approach 2:
The composite structure with thermoplastic polymer matrix provides mechanical reinforcement that compensates for lower basis weights, allowing the felt to maintain structural integrity during insertion while requiring reduced insertion forces compared to pure oxidized cellulose materials of equivalent strength.
3Productivity
If the felt structure is made more porous to improve water absorption and hemostatic activity, then hemostatic effectiveness increases, but mechanical strength and structural integrity decrease
Solution Approach 1:
The thermoplastic polymer matrix provides structural reinforcement that maintains mechanical integrity even when the oxidized cellulose fiber network is highly porous. The composite structure allows the porous oxidized cellulose to provide rapid water absorption and hemostatic activity while the thermoplastic framework prevents structural collapse during insertion and deployment.
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 felt exhibits sufficient mechanical strength, flexibility, and rapid hemostatic activity, with improved insertion forces and reduced adherence to surgical tools, enabling effective use as a hemostat in laparoscopic procedures with faster hemostasis and enhanced handling characteristics compared to conventional materials.
Implementation Method 1
The felt can independently of one another have a basis weight of from 70 to 200 grams per square meter, a tensile strength of more than 0.89 newtons, a Z-direction tensile strength of more than 0.22 newtons, a tear strength of greater than 0.22 newtons, and water absorption up to about 1000% of its weight.
Implementation Method 2
needle-punching and three-dimensionally entangling the carded batt to form a single layer nonwoven felt
Data Source
AI summary
The present invention is directed to a resorbable hemostatic nonwoven felt suitable for use in laparoscopic procedures and to methods for manufacturing said felt.