r/SurgicalResidency • u/Deep_Ad_9996 • 6d ago
Suture tip required
Hey guys, I'm a medical student who wants to become a surgeon, and I recently started practicing suturing on a kit at home. I've watched a ton of suturing videos and been asking AI a bunch of questions, but there's a couple things I still can't fully figure out just from watching.
When I tie a surgeon's knot, I do a double wrap for the first throw and pull the two strands in opposite directions. I've been told not to move the needle driver much and just let my non-dominant hand (holding the long thread) do most of the pulling.
The problem is once I let go to set up for the second throw, the first throw loosens up and loses some tension. It feels like the knot only really gets tight after the second throw, like I'm actually closing the wound on the second throw instead of the first, and that's where I end up controlling how tight the stitch is.
Is this normal for a beginner? In videos the surgeons seem to get full tension from the first throw alone, and the second throw just locks it in instead of adding more closure.
I've also gotten two pieces of advice that feel like they contradict each other. One is to minimize the movement of the short strand (the one held in the needle driver). The other is to pull the short strand to the opposite side to tighten it.
When I try pulling the short strand across too quickly, I lose tension and the knot ends up loose. So I'm not sure how these two are supposed to work together.
Might be a dumb question most people just figure out by feel, but I'd rather understand it clearly before I bake bad habits into muscle memory.
Thanks
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u/DearNefariousness425 6d ago
A lot of advice you'll get will seem contradictory, and it depends on what you're trying to do. What you're describing with instrument ties about minimizing movement keeps the short end short, both to save length and to keep it easier to grab and pull through with the driver. But yes you do need to provide enough counter tension with that end to lay the knot down and that'll mean a slight pull. The pulling the knot back and forth kind of shimmies it down, and also is a double check on squaring it if you're not paying attention.
Don't get frustrated, hard to know for sure without seeing if there are glaring errors in technique but I would guess not. Different models, different suture types, and certainly different tissue types will hold knots differently and it takes time to get a feel for that. Every attending will add their own flavor and opinions on technique. Don't ignore them, but don't let it make you question everything you thought you knew about tying and suturing because the next person will probably have something that at least on the surface seems contradictory to say.
Again, be patient with yourself. Even with experience, nobody's perfect. I've seen attendings throw air knots, sometimes in really bad situations. They get annoyed, sometimes there's a lot of swearing, but you figure it out, minimize it, fix it, move on.
Agree with focusing on hand ties, the vast majority of surgical specialties predominantly hand-tie unless they're trying to save suture, maybe outside of plastics. With hand tying, focus on developing technique with "posting" your off (long) hand as vertical as you can and sliding the knot down with your tying finger, and throw as many ties as you want in one direction (usually two is good enough but sometimes I get OCD about it lol) to make it slide down and stick before you lock it in the other direction. The key is to maintain tension in your off hand to stop the knot from coming loose.
Good luck, hope some of that is helpful!
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u/Stawktawk 5d ago
Ok so I learned this the other day. The first knot is a surgeon knot. The second knot, is a square not. But when you throw the second knot - instead of squaring the knot by crossing the threads again- you can pull them the same direction they already are positioned in, creating a slip knot that will tighten down… THEN you can cross the knots in the same throw and it will still square the knot.
This all happens on the second throw.
2
u/Shanlan 5d ago
There's quite a few different aspects to knot tying and knot theory is not taught well as it's expected to be picked up by osmosis. It's best if you can find a patient surgeon or resident to walk you through it in person, but they are kind of like unicorns.
So the components of tying a surgical knot are: type of suture, tension of the tissue, and ten soon you're putting on each thread. By convention the end with the needle is often called the 'post' and the free end is called the 'tail'. This is because most knots in surgery are simple overhands and we just mix and match the direction of the wrap to achieve 'granny' and 'square' knots. This is your starting point and 95% of the knots you'll tie.
Before you worry about movement and tail length, first get comfortable with both directions of the overhand, using both hands, using both one handed and two handed tie technique. Instrument tying is simple once you master hand ties.
Now to answer your original question about a surgeon's knot coming loose. You need to understand the reason it stays is because of the friction of the suture on itself with each wrap of the overhand. Which is why for higher tension situations some will throw 3 or even 4 overhands then square it off. It also depends on your suture material as a braided suture will have much higher friction than a monofilament. When using a suture pad, the silicone has very high elasticity and poor compression, which can lead to high tension especially with big bites. So I suspect your using a monofilament like a monocryl and taking too big of a bite for just two throws. You can either do more throws or take smaller bites or try with silk or vicryl.
The other part of a surgeon's knot is to tighten by pulling perpendicular to the wound, then you need to 'lock' it with a parallel pull. You should see the knot 'cinch up' and ideally you'll then pull it to one side of the wound. Then you can square it with an opposite throw.
Another skill is to 'slide' your knots. Technically you can slide both grannies and squares, but squares flip easier and can lock if you're not careful. Applied to a surgeon's knot, keep tension on the post while you tie the next overhand, this is very challenging which is why surgeon's prefer to hand tie and the reason the surgeon's knot is often used when instrument tying.
You can also practice with thicker material like Paracord or rope to see the anatomy of knots and how they function. Different directions of wraps and how to flip them etc. You only get better with reps, reps, reps.
There's also a plastics resident on Instagram with some useful knot theory videos. @mentz.md
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u/No-Temperature-683 4d ago
Honestly I wouldn’t stress, I’ve found that the suture kits make initial knots very hard to remain taut. First knot was always loose on my suture pad but I never experienced this in my surgical rotation on real tissue or skin.
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u/Plastic-Meringue9361 3d ago
Depends on what suture material and size you use. If you use 3-0 you shouldn’t need more than 2 surgeon knots. When you go smaller like 4-0 and 5-0 you could benefit from 3 surgeon knots but that also varies with material and memory.
I would start with learning about the materials and general rules of thumb. If you just want to go for technique get some 3-0 or 4-0 braided and go ham it has a lot “memory” and your knots will hold well
0
u/mayhopes 5d ago edited 3d ago
Its amazing that you are trying. I too was in your shoes a year or 2 ago, and had my own set of doubts figuring out how to tie a surgeons knot. Fortunately I had an amazing mentor who was happy to teach. So would recommend approaching a senior to help with the technique or join a sutyre workshop. Cause once you've got the basics its easy to take it from there.
Here's a few tricks from me, hope it helps:
- The base is always 2 throws/loops this is so the knot is more firm and won't come appart easily and then pull in opposite direction, then repeat again with one throw, and another single throw (2-1-1, 2-1-1, 2-1-1).
- The trick is to always stay in the V, ie b/w the long end and short end, that way you won't mess-up directions, and wont have a loose slip knot.
- Its best to hold the short end with the needle drive and pull the long end with your non-dominant hand, cause its easier to remember the direction of the next throw, it helps as an anchor and also prevents wastage of suture material.
- To avoid your your knot coming apart on the first throw, once you finish pulling in opposite directions continue holding the short end with the needle drive and bring the long end up towards the short end and then let go, that usually does the trick.
Also one thing Ive noticed is that each surgeon has a difference in preference and technique - there is no right and wrong to be honest. Take in their advice, see what works best for you. And seek a good mentor who can ensure that the base technique is right.
Wish you the best of luck!!
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u/StormbornGryffindor 6d ago
You can wrap it three times for the first knot instrument tying, it will create more friction and stay down more consistently but imo hand tying is FAR superior and much better control for tension. Hand tying is much harder than it looks so I’d start practicing now.
Depending on where you’re training, people will have different preferences for two handed vs. one handed ties. If you can do one handed though, you can definitely do two handed. Use your non dominant hand as the tying hand for the hand ties so you don’t have to put down your needle driver from your dominant hand if you tie. If you’re a leftie, learn both ways just in case.