🧵regarding the Bovie, which is one of the most commonly used tools in surgery.

I have decided to reorganize my Bovie content into something that makes more sense, which will require multiple 🧵. This first one will cover the very basics and is geared toward students.
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Briefly:
Recall that the Bovie is just a tool for completing an electrical circuit that includes a patient's body.

The current passes through the whole system, but because the tip of the Bovie is small, whereas the pad is large, the effect occurs at the place we want it to.

Short 🧵regarding the 'gold' Bookwalter ratchet and one feature that makes it behave differently from the regular ratchet, other than the fact that it rotates.

Also we'll look at a couple of other pointers about the Bookwalter knickknacks.
(1/ ) If you use the Bookwalter, you're aware that the tray comes with a large number of the standard 'clicky things' (officially: 'ratchets').

It usually also comes with some gold ratchets (usually 4 of these) and we all know that these *can rotate*.

🧵regarding the introducer sheath commonly known as a 'Cordis' catheter.

We'll go over what it was originally designed for and why it ended up being adopted by other specialties for entirely different reasons.

Also we'll look at its accessories and see what's inside one.
(1/ ) In the mid 1970's, angiographic procedures started to be done using introducer sheaths, which were much more convenient than passing all the devices through vascular cutdowns, as before.

There was some blood loss with each device exchange, and a sheath was patented to fix this.

🧵regarding the side hole at the end of most endotracheal tubes. This is the 'Murphy eye'.

You may or may not have noticed the Murphy eye before. Here we'll briefly go over what it is for, some unintended consequences of it, and (of course) a little history.
(1/ ) Frank Murphy was an anesthesiologist with interesting choices in facial hair that worked in various places (here seen at UCSF). At the time he devised his tubes, he was at Harper Hospital in Detroit.

Only a little is known about him, and is found here:
bit.ly/3ZRK2O6

For surgical history nerds:

Here is the main figure from Seldinger's 1953 paper showing what later became known as the Seldinger technique.

There seem to be 2 extra things that Seldinger did that most people probably don't do these days, as we'll see next:
(1/ ) One of the things Seldinger recommended was to push on the artery during the part when the wire is in to decrease bleeding. Most people skip this now, as the bleeding is usually fairly minor. Also it doesn;t make sense for locations such as the jugular vein.

Once again: a🧵about 🧵's

It's been about a year since I last posted these, but for the new folks, here is a collection of links to each of my 🧵 about surgical sutures.

9 of these are about suture types and the other 3 are miscellaneous suture-related topics.
⬇️(1/ ) Vicryl
(Polyglactin 910)

I am mostly referring to the Ethicon names since that's what our hospital carries.

https://x.com/rbarbosa91/status/1595336136221937666

🧵regarding 'instrument tying' of knots.

Instrument tying is a basic technique of tying surgical knots that is often used as an alternative to hand tying (which we've covered in previous 🧵).

As usual, we'll go the basic technique and also look at some other caveats.
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In the earlier threads about 2-handed and 1-handed knot tying, we learned that creating a square knot consisted basically of creating a loop and bringing a strand through it.

With instrument tying (R picture), this fundamental concept remains the same.

🧵regarding the useful technique of 'straightening the wire' during central line placement when the plastic guide is no longer within reach.

If you do a lot of central lines (or a lot of percutaneous procedures), this technique will come in handy over and over again.
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We are all familiar with the small plastic guide for the wire. It is meant to help you feed the wire into the needle.

It's usually there for the first attempt...but very often, especially if there is more than one attempt, the 'guide' gets lost somewhere on the field.

🧵**Results of the 'chicken suture' experiment are in**

As my followers may recall, 6 weeks ago I started an experiment in which a chicken with 10 different surgical sutures was buried, which was to be examined at the next change in UK 🇬🇧government.

Results to follow:
(1/ ) Here is the original post from 6 weeks ago.

Briefly: The chicken breast was buried on May 22, 2024 and contained 20 sutures: two 3-0 sutures of 10 different kinds, both 'absorbable' and 'nonabsorbable'.

https://x.com/rbarbosa91/status/1793522294532485435

🧵for the new residents and students on the meaning of 'French' and 'Gauge'.

We've covered this on here in the past, but a lot of new people are starting on surgical rotations, so let's look at them again.

As usual, we'll cover their history and what they mean.
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If you just want the short version:

The term 'French' is a unit of measurement of the *outer diameter* of a circular (or nearly circular) device.
1 'French' = 1/3 millimeters (or 0.33 mm if you prefer)

It's a direct measurement, so larger tubes have higher 'French' sizes.

🧵for junior trainees regarding the use of the non-dominant hand for surgical procedures:

We'll go over why it's probably even more important than your 'dominant' hand, and what I think is the key to developing proficiency with it, which may not be what you'd guess. 🧐
(1/ ) For this 🧵, I will use the words 'left' and 'right' instead of 'non-dominant' and 'dominant', respectively.

This is done purely to save characters in Twitter, as using longer words tends to take up more space.

Left-handed surgeons will of course have to reverse these terms.

🧵regarding some of the more novel *non-urologic* uses of Foley catheters.

It's been almost 2 years since I originally posted this, so many may not have seen this one (and I'll be doing reruns for a while...I need to spend April getting ready for #ASGBI2024 🧐.

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Foley catheters have actually been used intracranially, believe it or not...😬

Yang et al (2019) used Foley catheters to fill the cavities left after brain tumor resection in order to decrease hemorrhage and other complications.

scholars.direct/Articles/neuro…

🧵regarding the concept of 'stay sutures', which are used in almost every surgical specialty in circumstances where you need to retract or manipulate tissue, but a standard retractor or forceps won't do.

We'll go over the uses of stay sutures and show some examples.
(1/) The origin of the term 'stay suture' is unclear, and other names may be used.

I shall use the term to mean a temporary suture that is placed in order to retract the tissue or otherwise manipulate it. They normally take the place of a retractor, forceps, or one's hand(s).

🧵regarding the 'rapidly absorbable' sutures, which are used less often than other suture types, but fill specific roles in a number of different surgical specialties.

We'll go over the uses of (and differences between) Chromic, plain gut, 'fast' gut, and Vicryl Rapide.
(1/) Catgut has been used for suturing for many centuries, but it first became industrialized by the German company B Braun.

It is not (and probably never was) made from cats; instead it comes from the serosal layer of beef intestine or the submucosal layer of sheep intestine.

🧵regarding the 117 deaths in The Iliad where Homer provided details about the mechanism of injury:

Here we will run an M&M conference to consider whether these deaths might have been preventable if the Achaeans and Trojans had modern Level 1 trauma centers at the time.
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Background:
Recently, I read 'The Iliad' and noticed how often Homer described deaths with anatomic detail.

I then decided to look at these cases as though they occurred near a modern Level 1 trauma center with full capabilities.

Butler's 1898 English translation was used.

🧵regarding 1-handed knot tying:

We'll go over basic concepts about knots and how to tie the '1-handed' knot.

We will also explore why one of the 'throws' is harder than the other, and a different way to do it that may be new to many who trained in surgery in the U.S.
(1/ ) First, let's look at a few basics common to all square knots.

All of the different 'throws' involve creating a loop and then passing one of the two strands through the loop.

What we call '2-handed' or '1-handed' knots are just ways we've learned to do this. Nothing more.

🧵regarding the technique of 2-handed knot tying:

This one is for students and 1st-year residents. 2-handed tying is becoming a lost art in surgery, but I believe it is important to learn.

We'll start here with just the basic steps. More advanced concepts will come later.
(1/) If you want your first knot to be square, you generally don't want to start off with uncrossed strings (L picture). Instead, it's better to *cross* the two strings first before you start tying the knot (R picture).

There are 2 ways to 'cross' the strings, which we'll see next.

Upgrading a prior 🧵regarding polypropylene ('Prolene') suture: the workhorse suture of vascular surgery, though it also has other applications.

As usual, we'll go over some of the properties and uses of Prolene, and a little history.
(1/ ) Polypropylene sutures (I'll keep calling them 'Prolene' for the thread) were invented in 1969 and the US patent was approved in 1971. The patent was mostly based on a novel method of preparing monofilament polypropylene into a material that could actually be used for sutures.

Redo 🧵 regarding the concepts of 'traction' and 'countertraction', which are among the most important fundamental technical concepts in surgery.

This is modified from a🧵 from Nov 2022, so if you've started following in the last year, you may have missed this one.
(1/ ) First, some terminology.

"Retraction" is when one pulls on tissue to expose an area. Here, a retractor is used to expose the carotid.

But aside from allowing us to see it, the retractor is not doing anything to help us dissect it out. It is not providing 'traction' per se.

🧵regarding the Kocher clamp (or 'forceps' if you prefer).

The 'Kocher' is an instrument used by a wide variety of surgical specialists for a number of different things.

Here we will go over its properties and uses, and there will be more than the usual amount of history.
(1/) Before we start: I should point out that the terms 'forceps' and 'clamp' are used in an imprecise and random manner, both in scholarship and by industry.

The instrument we'll be talking about is alternatively described as a 'Kocher forceps' or 'Kocher clamp'. I'll use both.

🧵regarding the 'oiling' of surgical sutures, which was once a common practice but one that is quite rare today.

Here I will explain the purpose of 'oiling' a braided suture, some of the history, and some of the properties of braided versus monofilament sutures in general.
(1/) By 'oiling' (or 'greasing') a braided suture, one hopes to make it behave in some ways more like a monofilament suture, but at the same time still retaining most of the advantages of braided sutures.

Let us look at some of these advantages and disadvantages to see how they work.