Today I'm going to teach you all about wound classification. You're going to know how to classify a wound, when to classify a wound, and why it's important. All right, let's get started.
Welcome back to Citizen Surgeon. My name is Dr. Eric Pearson. I'm a pediatric surgeon, and I'm pumped that you're here today to talk about wound classification. So we're going to get right into it. Why do you need to know about wound classification?
Well the reason you have to know is because if you know how to classify a wound, you're going to know how to put your patients in a particular risk group for a surgical site infection. And surgical site infection has a ton of downstream consequences, whether that's systemic inflammatory response or sepsis or fascial dehiscence. Surgical site infection is a huge topic and we're going to also talk about that in the next video, so check that out. But today, wound classification. Let's get right into it.
So like I said, wound classification allows you to predict the risk of a surgical site infection. Whether that's a clean wound, or a clean contaminated wound, or a contaminated wound, or a dirty wound, each of these has a particular risk of a surgical site infection. And by the end of this video, you're going to confidently know how to classify that wound and also how to predict the risk of SSI for your patients. So the references that we're going to use today, we're going to use the Bible of Surgery or the one that I like the best which is Savison's Textbook of Surgery and I also have a couple of papers here for you to review and I'll put the links of these in the description below so you can check them out. The first paper is actually the CDC or the Center for Disease Control's definitions paper on wound classification and SSI.
So that's in great one to look at if you want to find out exactly how to classify these wounds as I'll talk to you about today. The second paper is a great paper that looks at several hundred thousand patients and the actual incidence of SSI and other complications with the classification of the wound. So I'm going to give you some numbers and some percentages but you can get into this paper to find out exactly what's the risk based on surveying several hundred thousand patients with clean Clean, contaminated, contaminated, and dirty wounds. So one of the things I think would be great to start with is if we look at some clinical case examples, some questions about how you would classify a particular wound.
Review these now, and then review them at the end of the video to see if it's clear to you what type of wound that is. All right, check these out. Let's say you have a 13-year-old with acute abdominal pain and a diagnosis of appendicitis. You complete a laparoscopic appendectomy and it's inflamed but no perforation. What is the wound classification?
Let's change this up a bit. Let's say you have a 40-year-old female with a follicular adenocarcinoma of the thyroid and you perform a total thyroidectomy. What's the wound classification? How about a 56-year-old male with melanoma at the right upper extremity? You do an excision with primary closure and a sentinel lymph node biopsy.
What are the wound classifications for each of these procedures? So by the end of this video, you will be confident in how to classify each of these wounds, as well as the wounds for every other procedure you can imagine. All right, so let's get into how to classify wounds.
The first wound type we run into is what's called a clean wound, or a type 1 wound. And so what is a clean wound? A clean wound is a wound that you make and there's no evidence of infection, you don't cross any cavity or hollow viscous, there's no break in sterile technique, you do a primary closure on the wound, and there's no history of penetrating trauma.
there can be a history of blunt trauma. And so what's an example of this? A couple of weeks ago, I did a simple excision of a ganglion cyst.
And so excision of a ganglion cyst on the skin, no inflammation, no crossing of the hollow cavity, I had no break in sterile technique, no history of penetrating trauma, there's no drains used. This was a type 1 or a clean wound. A laparoscopic hernia repair is another example of a clean wound.
So here you can see this is a child with an indirect inguinal hernia. I did a laparoscopic inguinal hernia repair, and that is a clean wound. So what are some other types of procedures that have clean wounds? Well, you can see this list here. So we have mastectomy, total thyroidectomy, splenectomy, ovarian resection, like we said, hernia raphe or hernia repairs.
Most of all these skin excisions, melanomas and such, where you don't have any inflammation. These are all examples of clean or type 1 wounds. So what is the risk of infection with a clean wound? Well the risk of infection is really low, in the single digits between 1 and 5 percent, depending on the patient's comorbidities.
And we'll talk about that in the surgical site infection video. All right. Let's go on to talk about class 2 wounds or clean contaminated wounds as these are really common in general surgery.
So here's an example of a class 2 wound. I have a picture of a gallbladder in the bile ducts. So a laparoscopic cholecystectomy in the setting of symptomatic cholelithiasis, so no evidence of inflammation or infection, this is an example of a class 2 wound. These are wounds where you have controlled entrance to a hollow viscous such as the respiratory tract or the alimentary tract or the genital tract or the urinary tract. Crossing into these holobiscus makes this a clean contaminated wound.
So what are some of the procedures that are clean contaminated? So here's a list of just a sample of procedures that are clean contaminated. Now it's important to keep in mind that this is without infection.
So of course a cholecystectomy is clean contaminated, but not in the setting of acute cholecystitis. Colorectal surgery is clean contaminated as long as you don't have inflammation like diverticulitis. Alright, so what's the risk of infection with a clean contaminated wound? Well the risk of infection of a clean and contaminated wound is still low.
It's greater than that for a clean wound. And you can say that this range is between three and 11%. And that is dependent on patient, treatment, and environmental factors that again, we'll talk about in the SSI video.
But three to 11% is a good range, also put out by the CDC and the ACS, as a risk for a surgical site infection with a clean contaminated wound. All right, let's get on to contaminated. And this is another example of wounds you see a lot as a general surgeon. So here we can see a coronal section of a child that has appendicitis with a fecal left. Now type 3 wounds are when you have inflammation.
So appendicitis is a great example of a procedure with a type 3 wound as long as there's not gross purulent or fecal contamination. Other things that make this a type 3 wound or a contaminated wound would be a major break in sterile technique. If there's trauma Penetrating trauma, that can be a type three wound as long as it's less than four hours. And of course, open spillage of the GI tract. Perhaps you're doing a bowel resection, but you spill a significant volume of GI contents into the perineal cavity.
that now instead of being a clean contaminated wound becomes a contaminated wound or a type 3 wound. And so what's the risk of infection with a type 3 or a contaminated wound? Well you can see here that the risk of infection goes up.
And now you're greater than 10% or 12 to 20% risk of infection. Again, and this is dependent on patient, treatment, and environmental factors. So now let's get on to the dirty wounds or the type 4 wounds.
And so here I have an example of a type 4 wound. This was a person that was involved in a motorcycle accident. They had significant contamination, and they presented to the emergency room with pus and a large open wound, as well as deep tissue infection. With the pus and the contamination and the wound that had been festering for a couple of days, this is certainly a dirty or a type 4 wound. So, what defines a type 4 wound?
So, a type 4 wound is defined as a wound... that could be an old traumatic wound that's greater than four hours. If there's gross purulent infection, so if there's pus pouring out of the wound, or if there is a perforated viscous, so in perforated appendicitis, where you have gross purulent debris throughout the abdomen, or in perforated diverticulitis, where you have fecal debris throughout the abdomen, like a HINCHY class IV diverticulitis. If you don't know that, look it up, or you can refer to a future video I'm going to have on diverticulitis.
But it's important to know that type 4 wounds have a really high risk of infection. So check this out. What are some other examples of type 4 wounds? If you did an incision and drainage of an abscess, or if you had...
a wound debridement as in this case with this patient or if you had more purulent debris and the risk of infection with a type 4 a dirty wound is much higher so over 25 percent at least And why is this important? Well, you may make decisions, and we'll talk about this in the SSI video, about leaving a wound open or doing a delayed primary closure in the case of a wound that has a higher risk of infection, and you have to take all of your patient comorbidities and environmental factors into account. And so now that we know how to classify and define a clean wound, a clean contaminated wound, a contaminated wound, and a dirty wound, and we know the risk of infection with these, when do we classify it?
Well, you classify a wound after the case because before the case, you're not going to know if you have gross spillage. You're not going to know if you've had a break in sterile technique. You may not know if there's significant inflammation. And that will change things from a type 2 wound to a type 3 wound or maybe even a type 4 wound.
And this will change the risk profile of that patient getting an SSI. Alright, let's dive into that paper that talks about the actual risk when we survey hundreds of thousands of patients. So this paper is an evaluation of surgical site infections by wound classification system using the ACS and NISQIP database.
So in this paper over 600,000 patients were evaluated in the ACS NISQIP database and they looked at SSI rates with wound classification when the wounds we talked about. So clean, clean contaminated, contaminated or dirty. Now when we look at this, about 50% of the wounds were classified as clean, 35% were classified as clean contaminated, 9% were classified as contaminated and roughly 7% were classified as dirty. And you'll see that these are actually a lot lower than some of the numbers I presented earlier. So in the wounds were classified as clean, you can see that about 2% of patients got a surgical site infection that was defined as superficial.
0.5% had a deep SSI. And 0.3% had an organ-spaced SSI. And again, we'll talk about these definitions in the surgical site infection video that's coming up soon.
If we look at clean contaminated wounds, 4% of those had a superficial SSI, 1% a deep SSI, and 2% an organ-spaced SSI. Thank you. You can see in contaminated, this jumped up to about 5% having a superficial surgical site infection, 1% with a deep SSI, and 2.6% with an organ-spaced SSI. And the dirty wounds had a 5% SSI that was superficial, a 2% deep SSI, and roughly a 5% organ-spaced infection.
And so if you have a dirty wound, that brings the total up to about 12% risk of getting a surgical site infection. versus a clean wound that has approximately a 2.5% to 3% risk of a surgical site infection. So I hope you enjoyed that talk today on wound classification.
Wounds can be classified according to clean, clean contaminated, contaminated, and dirty. I feel like I've said that 15 times in this video so you must know it by now. And let's just summarize this real quick.
So wound class we know gives the risk of surgical site infection. Wounds may be classified as clean, clean contaminated, contaminated, or dirty. Gotta know that by now. And of course, we can classify wounds in every case after the case is complete. Now that you know wounds, check out that next video on SSI or surgical site infection when it comes out.
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