Calcium Alginate Sheath Coating for Anastomosis Reinforcement
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Solution Overview
Problem
Existing resorbable medical devices for reinforcing tissue zones during mechanical anastomoses face issues such as high cost, uncertain viral harmlessness, risks due to prions, and mechanical weakness due to chemical incompatibilities between calcium alginate fibers and alginate ester solutions, leading to imperfect tissue reinforcement.
Innovation Solution
A method involving the manufacture of a sheath from calcium alginate, coated with partially esterified or etherified polyacid, and cut lengthwise to form a flat fabric with a pro-adhesiogenic internal face and non-adhesive external face, avoiding unraveling and ensuring effective bonding without additional binders, using a non-stick form and controlled coating and drying processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If calcium alginate fibers are coated with alginate ester solution, then tissue adhesion is improved, but mechanical strength deteriorates due to chemical incompatibility causing gelation and disintegration
Solution Approach 1:
The patent changes the chemical parameters of the coating solution by using partially esterified or etherified polyacids with specific esterification rates (70-90%) rather than using alginate ester. This parameter modification prevents the harmful gelation reaction while maintaining tissue adhesion properties, thereby resolving the contradiction between adhesion improvement and mechanical strength preservation.
Solution Approach 2:
The patent creates a composite structure combining calcium alginate fibers with partially esterified or etherified polyacid coating. This composite material approach allows the integration of two materials with complementary properties: the alginate provides tissue adhesion while the esterified polyacid provides mechanical strength and structural stability, avoiding the chemical incompatibility issues of previous combinations.
2Ease of manufacture
If the sheath is cut lengthwise after coating, then fabric formation is improved, but unraveling risk increases due to retraction forces
Solution Approach 1:
The patent applies the coating to the sheath before cutting it lengthwise. This preliminary coating action ensures that the coating is fully applied and cured on the intact sheath structure, providing structural support during the cutting process and preventing unraveling. The coating is applied to the complete sheath, and only after coating is complete does the cutting occur, eliminating the risk of unraveling during the cutting operation.
3Strength
If additional binders are used to bond calcium alginate and PAE, then bonding strength is improved, but device complexity increases
Solution Approach 1:
The patent employs a self-bonding mechanism where the partially esterified or etherified polyacid automatically bonds to the calcium alginate fibers through electrostatic interactions between calcium ions and carboxylic functions. This self-service bonding approach eliminates the need for additional binders or adhesives, achieving strong bonding while maintaining device simplicity and avoiding extra manufacturing steps.
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 resulting bioresorbable medical device enhances tissue adhesion and healing, reducing the risk of complications like fistulas and stenosis, while maintaining mechanical strength and safety during anastomosis procedures.
Implementation Method 1
coating of the sheath by means of a partially esterified or etherified polyacid (PAE) in solution
Implementation Method 2
a textile internal face of calcium alginate having tissue adhesion capacities in situ
Implementation Method 3
The excess solution is removed, then dried in hot air, at 45° C.
Data Source
Figure 1~2
Figure 3~4
AI summary
The method involves manufacturing a sheath from calcium alginate by manufacturing a guluronic type calcium alginate thread (2) and by realizing a knit with the thread (4). The sheath is assembled (6) in the tubular form of a non-sticky material. The sheath is coated (12) with partially esterified or starch polyacid solution with esterification or etherification rate of 80 percent. The coated sheath is cut (34) in lengthwise to obtain flat fabric. USE : Method for manufacturing an absorbable medical device to reinforce tissue areas in a mechanical anastomosis field. ADVANTAGE : The sheath is coated with the partially esterified or starch polyacid solution, and the coated sheath is cut in lengthwise to obtain the flat fabric, thus avoiding the risk of unraveling of the fabric of the sheath in the periphery or at the center, due to the retraction forces. The method enables reducing the risks associated with the use of mechanical grippers during anastomosis, using the control of the hemostasis and the wound healing in the time of the reconnected tissues to reinforce the anastomosis through natural way, thus avoiding the appearance of fistulas or stenosis. DESCRIPTION OF DRAWINGS : The drawing shows a flowchart representing the steps of a method for manufacturing a absorbable medical device.'(Drawing includes non-English language text)' 2 : Step for manufacturing guluronic type calcium alginate thread 4 : Step for realizing knit with thread 6 : Step for assembling sheath in tubular form 12 : Step for coating sheath with partially esterified or starch polyacid solution 34 : Step for cutting coated sheath.