Unlike regular sutures, dissolvable stitches can be absorbed by the body and eventually fall out on their own. That provides an unparalleled level of convenience because it eliminates the suture removal follow up appointment.
Absorbable sutures vs regular stitches
The major difference between dissolving stitches and regular ones is that the former will fall out on their own while the latter requires removal.
Below is a table comparing the two.
| Properties | Absorbable Sutures | Non-absorbable Sutures |
|---|---|---|
| Dissolvability | Yes | Yes |
| Requires removal | No but you can if you want to | Needs removal |
| Color | Yellow, purple, green, white (undyed) | Black, blue, green, metal, white (undyed) |
| Uses | Subcutaneous, oral, rarely external wounds | Mostly external wounds |
| Type of materials | Natural and synthetic | Natural and synthetic |
Hopefully that gives you a good general overview of the various differences between the two.
What they look like
The self-dissolving stitches look very similar to sewing knots. They can be colored or undyed but it literally looks like a sewing thread. Here is a photo of various colored sutures.
How to tell if they’re dissolvable
The two ways you can tell if your stitches can dissolve is by asking your doctor or by identifying their color. The answer from your doctor is definitive while the color method is more of a guess.
Color
You can try to figure out whether your sutures can fall out on their own by the color of the thread. Healthcare vendors typically will dye different suture materials to be a specific color.
- Absorbable stitches color can be yellow, purple, green or white.
- Non-absorbable stitches color can be black, blue, green, metal or white.
The color can usually give you the correct answer but you do have to be cautious with the white stitches. As you may have noticed, the color white is listed for both types of sutures.
The reason is because all of them are originally UNDYED but they become DYED for ease of recognition. Medical supply companies will sell both dyed and undyed versions.
Therefore, if you’ve white threads coming out of your surgical site, your guess would be equivalent to a 50/50 coin flip.
Label
You won’t have access to the label of the sutures that were used on your surgical site but your doctor does. The packaging will literally tell you if they’ll fall out on their own or not. This is why we say asking your doctor who did your procedure is the most accurate way to tell.
When sutures dissolve
When these stitches dissolve would depend on the type of material that they’re made of. Different materials will dissolve at different rates.
Below is a table of the various suture materials and when they dissolve. The dissolution times are based on manufacturer estimations.
| Absorbable Sutures | Dissolution Time |
|---|---|
| Fast Gut | 21-42 days |
| Plain Gut | 70 days |
| Chromic Gut | 90 days |
| Polyglycolic acid (PGA) | 60-90 days |
| Polydioxanone (PDS) | 182-238 days |
| Polytrimethylene carbonate (Maxon) | 120-180 days |
| Polyglactin 910 (Vicryl rapide) | 42 days |
| Glycomer 631 | 90-110 days |
| Polyglytone 6211 | 56 days |
| Poliglecaprone (Monocryl) | 90-120 days |
How long do they last
Despite the long dissolving times listed in the table for these sutures, they often don’t last that long in practice. The reason is because the estimated dissolution time is when the sutures become completely absorbed by the body.
However, there are many instances where complete absorption is NOT REQUIRED for the stitches to fall out. Once the threads have dissolved enough, it can be weakened to the point where they can simply “fall out”.
A common example would be wisdom teeth stitches, which often use chromic gut or vicryl sutures. The expected time for them to fall out is actually 10-14 days despite the 90 days for chromic gut and 42 days for the vicryl as listed in the table.
What we’re trying to say is that they don’t need to be completely dissolved before they fall out. They’ll fall out well before they get completely broken down!
How to dissolve faster
The natural dissolvable stitches are broken down by proteolytic enzymes and our theory is to drink extra pineapple juice to see if you can expedite it.
In a study by the American Journal of Surgery, catgut was found to be prone to rapid proteolytic digestion while in the gastrointestinal tract. Guess what has a lot of proteolytic enzymes… as you guessed, pineapple juice!
Pineapples are known to contain bromelain, which consists of a group of proteolytic enzymes. It is essentially a complex combination of multiple endopeptidases of thiol and other compounds derived from the pineapple fruit, stem, or root.
Before you go drinking gallons of pineapple juice… just know that there haven’t been any studies which have tested this in practice. It is merely our theory which we came up with by putting two and two together.
What if they don’t dissolve?
It is near impossible for them to not dissolve since they either get degraded via hydrolysis or proteolytic enzymes. Both of which are bodily functions that are commonly used. Essentially they are all made of materials that permit this.
The only exception would be the non-dissolvable sutures because those are made of materials that aren’t meant to dissolve.
What they’re made of
Dissolvable stitches can be naturally made of intestinal linings of ruminant animals or synthetically made of polymers and copolymers.
| Sutures | How its Made | Type of Material |
|---|---|---|
| Fast Gut | Natural | Animal intestines |
| Plain Gut | Natural | Animal intestines |
| Chromic Gut | Natural | Animal intestines |
| Polyglycolic acid | Synthetic | Polymers |
| Polydioxanone | Synthetic | Polymers |
| Polytrimethylene carbonate | Synthetic | Copolymers |
| Polyglactin 910 | Synthetic | Copolymers |
| Glycomer 631 | Synthetic | Copolymers |
| Polyglytone 6211 | Synthetic | Copolymers |
| Poliglecaprone | Synthetic | Copolymers |
We can broadly categorize them into three groups:
- Group 1 – All natural
- Group 2 – Synthetic polymers
- Group 3 – Synthetic copolymers (multiple types of polymers)
Natural
The natural absorbable sutures would be the family of gut sutures. They are made of collagen that is derived from the small intestine of ruminant animals (cows, goats, & sheep). Despite their similarity to food products, they’re not edible.
Synthetic polymers vs copolymers
The synthetic polymer stitches are made of long chains of repeating monomers. The copolymer stitches are made of long chains of different polymers that are stitched together.
Copolymer vs polymer vs monomer:
- Monomer – single molecule, often organic meaning it has carbon atoms.
- Polymer – multiple monomers that are stringed together into a long chain.
- Copolymer – multiple polymers that are stringed together into a long chain.
That is essentially what the synthetic threads are made of.
How dissolvable stitches work
Dissolvable stitches are able to dissolve because they’re made of materials that the body can readily breakdown and absorb. Depending on the suture material, they will either be dissolved via proteolytic enzymes or via hydrolysis.
| Type of Suture | Type of Material | How it Dissolves |
|---|---|---|
| Fast Gut | Animal intestines | Proteolytic enzymes |
| Plain Gut | Animal intestines | Proteolytic enzymes |
| Chromic Gut | Animal intestines | Proteolytic enzymes |
| Polyglycolic acid | Polymers | Hydrolysis |
| Polydioxanone | Polymers | Hydrolysis |
| Polytrimethylene carbonate | Copolymers | Hydrolysis |
| Polyglactin 910 | Copolymers | Hydrolysis |
| Glycomer 631 | Copolymers | Hydrolysis |
| Polyglytone 6211 | Copolymers | Hydrolysis |
| Poliglecaprone | Copolymers | Hydrolysis |
Proteolytic enzymatic degradation
The natural suture materials are literally made out of collagen from intestinal linings. Essentially the material is similar to food, the way they breakdown will be via proteolytic enzymatic degradation. Our body digests food all the time and absorb them.
Hydrolysis
All of the synthetic materials breakdown via hydrolysis which cleaves the polymers into monomers using water.
As an example, we’ll use the breakdown mechanism of polyglycolic acid (PGA) sutures.
Specifications of PGA:
- Monomer = glycolic acid
- Polymer = polyglycolic acid
- Essentially it is a string of glycolic acids
When PGA comes into contact with water, it undergoes hydrolysis and breaks down into glycolic acid.
Complications
Just because these sutures can be absorbed by the body, it doesn’t mean there are no complications. Here are a couple of potential complications which you may experience with them while you’re healing.
Potential complications:
- Infection. These are foreign objects to your body which means they can get infected. If that happens, it may swell up, turn red, or even ooze out pus.
- Rejection. The body can reject the stitches and try to push them out by migrating it towards the surface of your skin as it heals. This condition is known as a spitting suture.
- Irritation. The threads can get irritated and turn red around the surgical site. Alternatively, if the ends are too long it can be a source of irritation which are common with wisdom teeth stitches.
- Accidentally pulling them out. You don’t get stitches every day and some people may get curious and play with them. Unfortunately, there are situations where people pull them out accidentally!
- Falling out too soon. If the suture knots weren’t tied tight enough, they can potentially come undone while you’re eating. That means they would’ve come out earlier than expected.
If you experience any of the above complications you should contact your doctor. Further treatment may be required or new ones may need to be placed.
What if they don’t dissolve?
These types of stitches are made in such a way that they will self-dissolve without any intervention from you. The materials will naturally get broken down by the pre-existing bodily mechanisms. What we’re trying to say is that it is impossible for them to not dissolve.
Our bodies readily produce proteolytic enzymes that will break down the natural ones. If you have synthetic ones, they will get broken down with hydrolysis which uses just water.
However, as we discussed above there can be complications with the dissolution process. Your body can reject the sutures instead of dissolving them. In this case, the threads will get pushed out of your body in lieu of dissolving them.
Treatment
If they’re not dissolving, your doctor may need to remove the stitches instead of waiting for them to fall out on their own. Complete removal may not be possible at times.
- Complete removal. No local anesthesia is required for removal. Your doctor can grab the suture with forceps, college pliers, or hemostat and pull it out.
- Partial removal. If complete removal is not possible, it is recommended to trim the suture down to skin level as close as possible to the surface.