Introduction to Resorbable Surgical Sutures
Surgical sutures by definition serve the purpose of holding together the tissue edges of a wound or surgical incision. Resorbable sutures serve this same purpose of a traditional suture, while also by being degraded by the tissue metabolism in the body over time. By degrading in the body, the patient is saved from having to have another procedure to remove the suture, saving them time, money, and further discomfort. [1]
Resorbable Surgical Sutures have a relatively long list of manufacturers, materials, fabrication methods, and surface modifications that are currently in use. Each of these product details have been listed below along with certain relevant information.
There are many companies that manufacture these these sutures, and some leading companies today include Braun®, Vitrex®, Genia® and DemeTech®.
Examples of common current polymers used to construct these resorbable sutures:
Polyglycolic acid
Figure 1: Chemical structure of polyglycolic acid
Polylactic acid
Figure 2: Chemical composition on polylactic acid
Polydioxanone
Figure 3: Chemical structure of Polydioxanone
Caprolactone
Fabrication Methods
Braided: This structure consists of many small filaments that have been braided together to form the suture. This construction is relatively more expensive to produce, due to the fact that it has more steps in manufacturing. [2]
Monofilament: This structure is most easily comparable to standard fishing line, and is composed of one single continuous strand of the resorbable polymer. This form of suture is more commonly seen in the operating room than braided structures. [2]
Surface treatments
Surface coatings or treatments are usually composed of a polymer or co-polymer material and are most commonly used on braided sutures, although they are also found on mono-filament sutures.
Resorbable surface treatments can be split into two categories based on how they are broken down in the body. These two categories are water-soluble and insoluble.
Water-soluble: Coatings in this category generally do not last long at all once in the body, and can even be washed off prior to implantation in a sterilization process that sometimes takes place. This is why water-soluble coatings are used less than insoluble coatings when it comes to resorbable surgical suture applications. An example of one of these coatings is poloxamer 188, which serves to provide a slick slickness for ease of implantation. This slickness can also negatively affect the ability for knots to hold in place. [1]
Insoluble: Coatings in this category generally last almost the entire lifetime of the suture until it is fully broken down. An example of a common insoluble coating for these resorbable sutures is Polyhydroxybutyrate, which contains antimicrobial agents and can serve to help prevent infection. [1]
Resorbable sutures can be used for a wide range of internal injuries or surgeries. These applications can include things such as hernia repair, laparotomies (inside abdominal cavity), and various dental surgeries including wisdom teeth removal. The main purposes of using resorbable sutures is either to save the patient another trip to the doctor for removal, or to prevent having to re-open a closed incision made during surgery.
Figure 5: Resorbable suture used to close incision after wisdom tooth removal
Alternatives to resorbable sutures
While resorbable sutures are more favorable, another option when closing an open wound is non resorbable sutures. A drawback is that when removing non resorbable sutures, the patient may experience some discomfort. [4] Resorbable sutures also cause a lesser degree of tissue reaction after placement. The type of suture used depends on the doctor’s preference, site of the injury, and required characteristics of the suture. When tested, resorbable and absorbable sutures showed the same results in terms of cosmetic outcome. Another option in wound closure is staples. Staples are most commonly used as an alternative to sutures. The staples are rectangular shaped and made from steel. The main advantages of staples are that they can close a wound very quickly and have a low infection rate. Staples are most commonly used on linear lacerations in an area of the body that has hair, such as the head. A scar left from a wound closed with staples is worse than a wound closed with sutures, but hair is able to hide it. Staple removal tends to be more painful than suture removal. Tissue adhesive can also be used to close a wound. This method should only be used on small, simple lacerations. The wound must be cleaned thoroughly before this method of closing a wound is used. [7]
An example of how Resorbable Sutures are used
Resorbable sutures are usually used for facial lacerations, tongue or oral wounds, and hand and finger lacerations.
Studies in which the product has been evaluated
The United States Pharmacopeia (USP) has standardized mechanical tests for suture testing. They are as follows- suture length testing, USP 861 structure diameter, USP 871 needle attachment, and USP 881 tensile strength. These tests are performed on suture products entering the market before in body (human or animal) testing can be completed. Independently qualified testing labs such as DDL (an ISO 17025* accredited laboratory) and others tend to perform these tests. There is a big correlation between marketing and what testing lab what used.
When researching the amount of testing that is required for sutures it seems like there is more work that goes into getting approval to test than the actual testing process. The FDA has a twelve-page document (linked below) detailing the extensive approval process necessary to get a suture product approved for testing.
Once the approval for testing has been granted the process includes three main areas- biocompatibility, physical performance characteristics, and clinical studies.
Biocompatibility must meet international standard ISO-10993.
Physical Performance Characteristics are recommended to meet detailed guidelines outlined in monographs for absorbable sutures. They are Diameter <861>, Needle Attachment <871>, and tensile strength <881>.
Clinical Studies are highly regulated. The FDA dictates that all testing will be in vivo with animals only unless specific reasons for requiring human testing are proven. Throughout research it seems rather impossible for human clinical trials to get approved before extensive animal testing has occurred.
*ISO/IEC 17025:2017 is the international standard by which a laboratory’s commitment to quality and technical competency is evaluated and is becoming an essential standard for testing facilities serving the medical device industry.
Advantages and deficiencies Observed in these Studies
This type of testing is beneficial due to the reduced cost of not having human trials. Through testing with animals an independent laboratory can be contracted out to perform most tests necessary for FDA approval. It also takes less time and effort than human trials. The FDA only get deeply involved and concerned if a new product is destricbed as:
- a formulation dissimilar from formulations previously cleared under a 510(k);
- a new technology, i.e., technology different from that used in legally marketed surgical suture devices
- indications for use dissimilar from indications for use of sutures of the same type.
So as long as a product does not meet these criteria they are not very involved which is an advantage. Disadvantages occur when one of these points is met. From here the FDA buckles down and requires expressive background information on how the product was formulated. If any point is met this also clears them for human trials. This is a much more time consuming and expensive process to complete.
Benefits come from being able to contract out independent labs from a marketing standpoint. Being certified by a lab such as DDL can be seen as a marketing strategy- adding credibility to your product.
Business Studies
All companies marketing this product seem to focus on testing results. As mentioned above many times these companies such as Demetech, Vitrex, and Bruan all discuss how their products performed better and at a higher scale than competitors. They draw customers in with calming photos that usually have a blue tint to them since that color has been proven to reduce anxiety in humans. Marketing can also focus on the surface treatments applied to the suture. Talking about how its water soluble, soluble over time, or if they need to be removed.
Fabrication is difficult; every company wants to keep their process protected. It is easy to find what the material is mainly made of but after that fabrication methods are difficult.
Evaluation is apparent due to all of the FDA guidelines. Companies always disclose they have met the requirements deemed by the FDA. They will also speak on how they are verified by independent lab companies and other organizations. This goes hand in hand with marketing.
Biotextiles 2020 
Considerations:
Start off with an introduction paragraph about what resorbable surgical sutures are and why/when they are used
Rather than list common polymers (I found the structures unnecessary for the purposes of this blog), give example products on the market and explain how they are made (braided/monofilament) and what they are made of
Include a heading for the application paragraph
Make heading capitalization consistent
Include references and citations
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Start of describing what a resorbable suture is and how it works, don’t just jump in to talking about the manufacturers. Maybe make the pictures of the materials used smaller because it takes up a large portion. The picture and videos were helpful to understand how the product works and is implanted. Good list of alternatives for a resorbable suture. Overall, it seems like you are still in the process of creating the blog and more information needs to be added. Also, don’t forget to add resources.
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Good information so far on materials and textile structures used in resorbable sutures, maybe look to include results from clinical or in vitro studies to give evidence to your claims about the different pros and cons of this product compared to alternatives. Also, including some information on how the suture breaks down over time depending on the polymer used would help to explain why it may be a suitable product for some applications but not others.
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Team 7 here.
The blog on Resorbable Surgical Sutures is very informative. The paragraph about the application of the sutures needs a heading. The blog needs more information about studies and the market evaluation of the sutures. Also, more information about the desired properties of surgical sutures would be helpful.
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I really like the way the information is given on this blog, it is very easy to follow. Starting off with the chemistry and polymers may be overwhelming for some viewers so maybe change the layout for that. All the information needed is given and easy to understand. I liked that the pictures were able to relate to surgeries that many people have gotten.
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Team 8
Overall the blog was easy to read, especially the material. The format looks great. The blog does need more information on studies and a reference section.
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Team 2 here,
I think what you’ve done so far is really good. An introduction paragraph would be helpful. Try to grab the readers attention so they want to keep reading more about your textile product. Make sure you try to cite your sources in line with what you write. You’re doing great!
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