Let's Learn About Sutures!

[CheesePotato, BSN, RN]

Ah yes, the joy of learning suture.

::cracks knuckles:: Let's talk some suture, shall we?

First and foremost, allow me to disclose that my place of employ utilizes Ethicon suture (as have other OR's in which I've worked), therefore I will do my best to generalize where possible. I will also try to keep it simple. I can ramble for hours about suture.....it's a problem. And you know what they say, acknowledging a problem is the first step to recovery.

And away we go:

What the devil is the difference between the sutures?

Well, sutures are comprised into three different varieties: Natural, braided (multifilament) and non-braided (monofilament).

Natural sutures:

Plain gut

Chromic gut

Examples of multifilament:

Nurolon

Vicryl

Cotton

Silk

Ethibond

Monofilament:

Nylon

PDS

Prolene

Monocryl

Sutures are then further categorized by whether each is absorbable or non-absorbable.

Absorbable:

Vicryl

Chromic gut

Plain gut

PDS

Monocryl

Nurolon

Non absorbable:

Nylon

Prolene

Silk

Ethibond

Okay, before we get too far into our discussion, let's pause and break this all down as far as what this means to you as a circulator.

~~ When a patient has an infection, most doctors will not use a multifilament suture when closing an infected wound. Why? Because the braid in a multifilament suture is a lovely little breeding ground riddled with nooks and crannies that allow the bacteria to breed like crack riddled bunnies.

Sub point: Monofilament lacks these nooks and crannies and therefore tends to be favored. Infected patient? Think monofilament sutures.

~~ When a patient is "spitting suture" it tends to be a non absorbable or slow absorbing suture (we will get to that in just a sec. Hang with me).

So, let's talk absorption info, shall we?

Plain gut: 70 days

Chromic gut: 90 days

Vicryl: 55-70 days

Monocryl: 90 - 120 days

PDS: 180 - 210 days

Nurolon: loses something like 20% of it's mass, if you will, per year, if I remember correctly. ::nudges sleeping brain::

What this means to you: Well....honestly? Not too terribly much. Just some good info to know. I've only used this piece of info twice in my career and both times it was in answer to a surgeon who then stared at me as if I had three heads.

Well, Ms. Potato, you say, that's all find and dandy, but where on the body are the various sutures used?

Well, my friend, before I can answer that question honestly, I must introduce you to one more of two additional determining factors that marks where in the body a suture goes: needle type.

Right then.

There are then six types of needles: Cutting, reverse cutting, taper, trocar, blunt, and side cutting.

Don't panic. Here's the breakdown of each and what they are typically used for:

~~ Cutting: Triangular shaped needle (if you were to stare down the tip) with the cutting or sharpened edge found to the inside. (more superficial closing sutures. Needle call letters or code example: CR)

~~ Reverse cutting: Triangular shaped needle with sharpened edge found to the outside. (also more superficial closing sutures. Needle call letters or code examples: FS, PS, M, LR, KP-3)

~~ Taper: round needle tapering to a point (this is the most atraumatic needle type, hence it is used in deep fascia closure as well as on bowel, vessels, nerves, tendons, etc. Needle call letters or code: CT, CT-1, SH, UR, BB, BV)

~~ Trocar: rounded needle ending in a cutting point. My facility does not use these needles. Alas, I am unable to provide further info. I apologize.

~~ Blunt:....yeah....blunt. Um...we don't use blunt needles at my facility. Ever.

~~ Side cutting: Flat needle with cutting edge to front. (eye surgery only). I'd be lying to say I know. The last eye case I worked on was an enucleation. So. Um. Yeah. We didn't fix the eye.

Moving on! So what's the last determining factor (other than surgeon preference) that determines what we hand them?

Why, size of course. After all, it always comes back to size.

And I'm not just talking needle size. Pause.

Although that is a factor. If I'm working on a finger, giving me a veritable harpoon to use isn't going to work so well, ya know? It's all about common sense with this one. If the work is delicate--think eyes, plastics and the like-- are you going to offer the surgeon the biggest, gnarliest needle in your orificenal? I would hope not. Small and delicate for well...small and delicate. Mmhm.

And go.

Size is also a reference to the density of the suture or what is called tensile strength.

It's written on the outside of each box and you have heard it since the day you started. It's that pesky numeric coding in big bold letters: 0, 1, 2-0, etc.

So what in the devil does that mean?

Here's how it works: think of it like learning negative numbers in school. The Higher the positive number, the bigger the suture. The Higher the negative number, the smaller the suture. Example: Which is bigger: 3 or -8.

Also, sutures that do not have a 0 to follow are commonly referred to as a "number XX".

In practicum:

A number 5 Ethibond is going to be the suture world equivalent of twine rope where as a 10-0 Nurolon is as fine if not finer than a human hair.

Any suture that is a positive or high number without an 0 to follow is thick. Anything with an 0 to follow is fine. As the front number rises, the thickness of the suture grows more fine.

More examples, in case I completely lost you:

Number 2 Nylon: thick

2-0 Vicryl: Fine

2-0 Nylon: Still fine.

2-0 Monocryl: ....you guessed it. Still fine.

Number 1 PDS: thick

3-0 Vicryl: More fine than a 2-0 Vicryl. Thicker than a 4-0 Vicryl.

Make sense?

Okay! Time out to put this together before we get to putting it all into the working world:

Just like needles size, suture thickness is a matter of common sense: You do not use a 10-0 Nylon to hold together the fascia of an abdomen or sew together the muscles in a knee. Kinda wouldn't work.

So where do you find the thick suture? In the deep parts of the wound and where there is going to be natural resistance and pulling put on the suture by the living body.

Exceptions: nerves and vessels. Again, common sense. To sew the little walls of an artery in a bypass, are you going to use a Number 2 suture? God no. Think more along the lines of a 7-0. Fine suture for fine work. Big suture for big work.

So when the doc is sewing deep, he's going to ask for that Number 1 suture or an 0 (typically called an "o" in our little corner of the OR globe). When the doc is sewing the shoulder closed and is working on sub-scap or cuff, is he going to want a 5-0? Nope. Those muscles are going to PULL on that suture. Number 2 it is then.

Now a quick note: remember, the number is not only an indicator of size but of tensile strength. Higher the number: stronger the suture. Higher the number with an 0 to follow: weaker the suture.

Now comes the fun part:

Let's put it all together. With some practical application discussion. Heheh.

:: poof!:: I am now a doctor. Not just any doctor--the one in your OR. And I'm bored so I'm working on a belly case. I'm rooting around in the bowel and I want to suture some bowel together.

Suture of choice? 2-0 (delicate suture for delicate work. Not too weak, not too strong) Silk (non absorbable). On an SH (Taper needle: atraumatic. Won't do me a lick of good I'm slashing my bowel to bits to try to sew it together, ya know? P.S. This needle is also called a GI needle by some scrubs)

And this is how the scrub will ask for it, "I need a 2-0 silk on an GI". Some scrubs have the actual suture catalog numbers memorized, which is fine, but I prefer to know my needles and suture types. I digress.

Great! So my bowel sewing has gone wonderful and I think I'm done because I'm hardcore like that. So I want to close. I'm just starting to close so I'm going to be sewing deep.

Suture of choice? 0 (Strong! Those belly muscles tend to pull.) PDS (I want this suture to hang around for a looooooooong time to be sure the wound closes well) on a CT-1 (again, taper needle. I don't want to cause undo trauma if I can prevent it. Quick note: some scrubs refer to a CT needle as a "general closure", as in, "I'll take an 0 PDS general closure" ).

What's that? You're out of 0 PDS? Well drat. I guess I'll take a 0 Vicryl on a CT-1.

Okay, so that's done. I'm going to close my next layer of fascia.

I'll take a 2-0 Vicryl on a CT-1. (The tissues are getting more delicate as I work towards the surface, and therefore my suture should follow suit).

You know what? I'm going to put a drain in my patient. What should I use as a drain stitch?

How about a 2-0 silk on a FS (Non absorbable so it will still be there in good shape later and reverse cutting as I'm going to go through skin and cutting/reverse cutting makes it smooth like silk).

Wow. Almost done. Let's close skin.

I would like a 4-0 Monocryl on a reverse cutter or whatever you got like that. Yeah, that will do. Skin is delicate and I'm going to do a lovely plastics closure so my patient doesn't scar as badly. I need something fine and sharp with a capital S.

Things to take away from practical discussion and various other sidebar comments:

~~ All boxes/suture packets are labeled with all the information that you need: needle type (including picture as well as written description), number of size and type of suture.

~~ As you work deep to superficial, suture tends to be come more fine. Remember the exceptions mentioned before.

~~ Popular drain stitch tends to be silk or Nylon. Depends on doctor preference/specialty. Where I come from General/Neuro/Cardiovascular surgeons tend to use silk. Ortho uses Nylon.

~~ Ortho tends to use more cutting needles as what they are working on is less delicate.

~~ Ortho tends to also use Nylon to close skin. Again, surgeon preference.

~~ When in doubt of needle type (you will be surprised how many doctors don't really know the difference), grab one of each and bring them close to show the field/surgeon. Let him choose. Choices are good.

~~ Always read/consult surgeon preference cards/confirmation sheets as any good circulator should. Know what your doctor tends to favor normally so you know what to offer when he throws you a curve ball.

~~ Some suture does not have a needle. Umbilical tapes and tie sutures do not. Ties come mostly as either Silk or Vicryl. In spite of this, they follow the other rules listed above: " I would like 0 silk ties" . These sutures tend to be used in the tying off of vessels to large to be bovied into submission.

~~ There is such a thing as a straight needle called a "Keith needle". Can be found on Silk and Prolene, just as examples, and is a straight "traditional" looking needle. Looks just like what you think of when you think of sewing. Why is it used? Mostly used in the securing of central lines and art lines superficial through the skin.

~~ Some sutures come "double armed" (meaning there are two needles connected to one suture): Prolene, especially. How to know? The box as well as the package will show an image of two needles with a fine line between them.

~~ Sutures, mainly Monocryl, Nylon, Vicryl sutures can come as both dyed and undyed. Again, it's on the box whether the suture is dyed or undyed and most scrubs will specify as will the docs. "I want a 2-0 undyed Vicryl on a FS-1"

~~ There are sutures known as "pop off" sutures or "poppers". They tend to come in packs of eight and will be labeled on the box as "controlled release" as well as circled in an oval shape with the letters CR followed by the number of sutures in a package. In a package of eight this looks like, "CR/8". Example of dialogue: "I need a pack of 2-0 silk pop offs, please." They are used in places that need multiple sutures to close an area (mostly bowel and abdominal as well as spine) and allow the needle to be released and removed from the field for the surgeon to tie easily.

~~ The size of the needle image on the box is the exact size/shape of the needle in the package.

~~ Some suture comes "looped", meaning that the suture literally loops back and reconnects to the needle leaving no true dangling end. The way to identify this type of suture quickly is through the image on the box: it will show the needle with a loop at the end of it. The box will also be labeled accordingly.

~~ Take time to look over a suture cart/boxes and become familiar with where on the boxes the information described above is located.

~~ And, as always, never forget to add your needles to the count.

I hope this helps. I'm sorry for any forgotten details or confusion; between call, espresso, and sleep deprivation, I'm afraid I'm a touch scatterbrained today. Any questions/comments/ etc, let me know. I will be more than happy to help in any way I can.

Good luck to you and welcome to the world of OR nursing.

Kindest regards,

~~ CP ~~

[silkysteph]

thank you very much!

[FutureORCRNFA]

FANTASTIC JOB CheesePotato! I could never have said it better myself! This is an excellent training course in and of itself for all aspiring STs and new grad nurses to the OR! Once again….FANTASTIC!

[OR1228]

Thank you!

[flying_ace2]

This is GREAT information! As a new grad in the OR, I definitely appreciate that you have done an excellent job of explaining sutures. I've been working only for about a month now, and I wish someone had gone through this with me when I started - it is very helpful!

[scrubulator]

Thanks!! I just have one additional question that is related to suturing. What are the levels of closures? Like fascia closure, subcutaneous closure, subcuticular closure? What's the order?

[Rose_Queen, BSN, MSN, RN]

The levels of closure are going to depend on the type of surgery and the patient's tissues. For example, I work in heart surgery. Our first layer of closure is the sternal wires or braided cables. This is followed by a deep layer with either 0 Vicryl or 1 Vicryl. Then, we close subcutaneously with either one or two layers of suture depending on the amount of tissue, usually a 3-0 or 2-0 Vicryl. Then, the skin is closed with a subcuticular barbed knotless suture such as V-Loc, Quill, or Stratafix.

Ethicon (one of the companies that makes sutures) provides this educational brochure which goes into probably much more detail than you'll ever need and does break some of the suture choices and techniques into surgical specialties: http://academicdepartments.musc.edu/surgery/education/resident_info/supplement/suture_manuals/ethicon_wound_closure_manual.pdf

[abhyatt1]

Amazing post! Thank you soooooo much! I've been in the OR for over 2 years and never could get anyone to thoroughly explain sutures to me. I have a friend at work who I'm going to share this post with. Thanks again. -ah

[ehil007]

Why a dyed or undyed preference, just out of curiosity? I start an OR training program soon and I'm trying to get a head start!

[WhoDatWhoDare, BSN, RN]

All other things being equal, it depends on surgeon preference on whether they want the suture visible (inside the abdominal cavity during a laparoscopic case) or if it's in a spot like the face (e.g. a plastics surgeon will almost always want UNDYED).

[SurgicalTechCST]

Marvelous "pocket sized' suture breakdown and review! Very well done!

When I was in Surgical Technology school back in the Dark Ages, our instructor, who was an old-school OR and ER nurse, taught us her way of figuring out sizes of sutures relative to their "0" designations. It was very visual, and seemed to work nicely.

She drew a number line on the board, and divided it into the usual positive and negative halves. For the suture that has the 2-0, 3-0, 4-0 and so on size designations, she said to simply relate the first digit to the actual NUMBER of ZEROS of the size. Then, at the 0 space on the number line, she put a "0" above and a "0" below the line in the same space vertically. That's an "0" (oh) suture, smaller than a "1", because its less than 1, and there's not a 1 or any other number there. It's the starting point. For a 2-0, she wrote "00" behind or to the left (negative side - getting smaller) of the "0" underneath the line and "2-0" above it, followed by the 3-0, which put "000" further to the negative side, under the line, and the 3-0 above it - still smaller yet than the 1. And so on, more zeros and a one-step higher designation each time.

Then, think that in order to save space on packaging, instead of writing that many zeros on everything, the suture companies simply use the number OF zeros (2, 3, 4, all the way up to 10) next to the "0" instead of writing out "0000000000" and making you count that number of zeros on every label, and possibly getting a 10-0, shown above, confused with a "000000000" or a 9-0.

More zeros means smaller and smaller than #1 incrementally. If you actually draw it out, it makes perfect sense. (I tried that on here, but it was becoming rather onerous trying to get things to line up!)

As for needle sizes (we had one student who was obsessed for some reason with needle sizes, instead of cutting or atraumatic styles) of selection. Needle size always follows suture size, but it's the presence or lack of a cutting surface that makes the difference. You would never see a #5 "harpoon size" needle carrying around a 4-0 suture! Likewise, there's no need to worry that you'll ever have to choose between a 7-0 needle hauling around a #2 size suture and a 7-0 needle with its companion 7-0 suture. Besides, by the time you get to something as small as a 7-0 suture, you can bet your surgeon and the assistant will be wearing loupes or using a microscope!

Anyway, I thought I would pass this along since it seemed to help us quite a lot. Hope this is helpful to someone else too.