Name:
Lag Screw Technique (Small and Large Fragment)
Description:
Lag Screw Technique (Small and Large Fragment)
Thumbnail URL:
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Duration:
T00H05M00S
Embed URL:
https://stream.cadmore.media/player/7a3c3d03-8151-491d-9402-8650e9b775d1
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/7a3c3d03-8151-491d-9402-8650e9b775d1/Lag Screw Technique (Small and Large Fragment).mp4?sv=2019-02-02&sr=c&sig=luAVt4XppupXG%2F35hQ74FPcd%2FSRFZruJlugR4TpgRmg%3D&st=2024-11-23T10%3A08%3A07Z&se=2024-11-23T12%3A13%3A07Z&sp=r
Upload Date:
2024-05-31T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
So viewers, today, I'm going to show you how to apply a Lag Screw. A Lag Screw is commonly used in orthopedics to achieve primary bone healing. So there are two ways you can use Lag Screw. Either you can use a partial threaded screw. That is an easier technique. However, a lot of times we are facing fractures of the cortical bone and we have to use a fully threaded cortical screw in order to apply a lag.
So to the demonstration will be how to use a fully threaded cortical screw in large fragment and small fragment if you have to apply a lag screw. So before I demonstrate you how to do a lag screw, I would like you to focus on the basics of why and what goes on. What is the idea behind doing the lag screw? So I've drawn this bone. This is the fracture line.
Now if you are applying a lag screw, the first important principle of applying a lag screw is your screw should be perpendicular to the fracture. So if this is the fracture, your lag screw has to come absolutely perpendicular to the fracture line. Now, when we talk about lag screw, we talk about gliding hole. So the first cortex is the gliding hole.
If you're applying a lag screw through from this direction, this will be the gliding hole and the second hole will be a pilot hole. Now the gliding hole is called gliding hole because it's big enough for screw to easily glide in it. So if you're talking about a small fragment, screw that, it's 3.5. So we will use a 3.5 drill bit so that it can easily glide in it.
And same way if you are using a large fragment then you will use a 4.5 drill bit so that this becomes a gliding hole. So the pilot hole is also called as thread hole. For a small fragment, we will use a 2.5 drill bit. And for a large fragment the pilot hole, we will use a 3.2 drill bit. So I have written here gliding hole as G, pilot hole as P. So if you see just to reinforce in small fragment, gliding hole is 3.5 mm, not 3.2 which commonly people think and pilot hole is 2.5 mm. Same for large fragment gliding hole is 4.5 mm and pilot hole is 3.2 mm. So next I will show you a demonstration of how to apply a lag screw.
So for doing a lag screw, you will require certain equipments. I have. I'm here having the basic equipments that you will require if you are putting a lag screw. So let's talk about small fragment first. So the first thing, the first step of putting a lag screw will be to put a gliding hole. So the gliding hole will require a 3.5 mm drill bit. For pilot hole,
we will require a 2.5 mm drill bit. And of course for this when you are using this drill bit you require this sleeve and here it says 2.5 mm. For the Tread hole or pilot hole and 3.5 mm even for gliding hole. Once you have made this hole then you would use a countersink and the countersink will create a space for screw head to go inside the bone. So that it's not prominent.
And it's especially important if you are using an utilization plate on top, otherwise plate will not seat on the bone. Once you have done the counter sink, your next step will be to measure the depth of the screw. So this is a depth gauge, then this is the tap. If you're using a small fragment, you are going to use a 3.5 mm tap and then you will require a screwdriver, the hexagonal screwdriver for putting your lag screw.
So now let's start on large fragment. So a large fragment gliding hole will be 4.5 mm. So it's very easy if you're using a small fragment, 3.5 mm set, then three gliding hole is 3.5 mm if you're using a large fragment 4.5 mm Screw gliding hole will be 4.5 mm. For pilot hole or thread hole you will use a 3.2 drill bit. And if you can see the sleeve that you'll be using it here, it says 3.2 for pilot hole.
And 4.5 mm for gliding hole. And of course, like small fragments, you require a countersink. So use a countersink and then use a depth gauge. Then you will use a 4.5 tap and then you will screwdriver to put your right size screw. Now, the main purpose of a lag screw is to create compression.
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