Category Archives: Abdomen

Stab To The Abdomen: The WTA Algorithm

I’ve spent the last week discussing the hypothetical case of a young patient with a stab to the abdomen. I worked through some of the thought processes regarding physical exam, imaging, and choices for management. Fortuitously, it would seem, The Journal of Trauma published an algorithm on this very topic from the Western Trauma Association (WTA).

The WTA Algorithm Committee reviewed existing data to start the process of developing this algorithm. As could be expected, very little high quality data was available. So the final algorithm is a synthesis of existing lesser quality studies, expert opinion from the committee members, and commentary from the membership.

Here are some of the highlights:

  • Unstable patients go straight to the operating room (A)
  • Patients who cannot be examined (unconscious, head injured, intoxicated) should be evaluated for peritoneal penetration with local wound exploration, ultrasound, CT, or laparoscopy. If positive or equivocal, proceed to exploration. (B)
  • Patients who can be examined should be managed by location of the stab. Flank injuries are lower risk and should be scanned. Anterior stabs can be evaluated using observation, local would exploration, or CT scan,
  • Positive results generally proceed to laparotomy. The algorithm states that laparaoscopy “may be performed in select stable patients by a highly skilled surgeon experienced in minimally invasive surgical techniques.”

As with any algorithm or practice guideline, nothing is etched in stone. These tools are good for about 90% of the clinical situations you will encounter. If you end up off the beaten path, you will need to use your best judgment to provide best treatment for your patient. Just remember to document your rationale, because you may very well have to justify it to your peers.

Click the diagram below to see a full size version.

Reference: Evaluation and management of abdominal stab wounds:
A Western Trauma Association critical decisions algorithm. J Trauma 85(5):1007-1015, 2018.

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What Would You Do? A Teensy Weensy Stab To The Abdomen – Part 4

We’ve gotten the young man with the teensy weensy stab to the abdomen with a bit of omental evisceration to the operating room. Now what should we do? We’ve already decided that he needs an exploration because of the known penetration. How should we go about it?

There are two choices: diagnostic laparoscopy vs laparotomy. Which is better? Let’s talk about laparoscopy first. This tool has been around now for over 25 years. There has been variable acceptance for use in trauma during that time because it tends to take more time and may have a higher rate of missed injury. Both factors have major implications in patients who have active bleeding and small injuries, respectively.

On the plus side, a truly negative (nontherapeutic) exploration tends to be more benign, with rapid recovery, faster time to discharge, and potentially fewer complications when evaluated with a scope. But on the minus side, small injuries can be notoriously difficult to find. What does that small wisp of blood mean? This is not nearly as clear as the meaning of other colors (green, brown). The decision to open can be difficult, particularly for surgeons who perform a high number of laparoscopies in the non-trauma portion of their practice.

Trauma laparotomy is traditionally a large operation with a generous incision and meticulous exploration. This can lead to significant postop pain and morbidity, particularly when no significant pathology is found. Unfortunately, the literature appears to be quite polarized. The surgeon is either pro-laparoscopy, or pro-big incision, and tends to brace their preferred procedure almost exclusively.

But there is a middle ground, and that is what I would choose in a case like this. The surgeon must consider the likelihood of reliably finding the size of internal injury based on his or her assessment of the external wound, as well as the probability that the exploration would be non-therapeutic. So in this case, I would worry that a bowel injury could be only a few millimeters in size and might be missed using only the laparoscope. But I also think that there is a good chance there may not be an injury at all, so I would not be inclined to start with a huge incision.

My choice is to perform a “mini-laparotomy”, making an incision just large enough to explore all of the bowel and visualize the retroperitoneum. I can generally do this through an incision large enough to get my palm into the abdomen, about 6cm. I am confident that I can easily find all injuries, and make the incision larger if warranted. Postoperative pain is better, and discharge if no injuries were found can happen in 1-2 days.

Unfortunately, I can’t find any papers that examine this middle ground between laparoscopy and full laparotomy. But I’ll keep looking! How would you have managed this case? Comment or tweet, please!

In my next post, I’ll review the official algorithm for evaluating stabs to the abdomen recently published by the western Trauma Trauma Association.

References: 

  1. The role of laparoscopy in management of stable patients with
    penetrating abdominal trauma and organ evisceration. J Trauma 81(2):307-311, 2016.
  2. Diagnostic Laparoscopy for Trauma: How Not to Miss Injuries. J Laparoscopic Adv Surg Tech 28(5):506-513, 2018.
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What Would You Do? Teensy Weensy Stab To The Abdomen – Part 3

In my last post, I described the plight of a young man who had sustained a stab to the abdomen. It appeared that a very tiny bit of omentum was hanging out of the wound. What to do?

I listed three options:

  • Local wound exploration
  • CT scan of the abdomen
  • Proceed to the operating room

So let’s work through these. First, local wound exploration (LWE).

LWE is a diagnostic procedure to determine if a sharp wound has actually or potentially penetrated a vital area. It is usually performed in the neck to determine if the platysma has been violated, or in the abdomen top check for peritoneal violation. In this case, you would use it if you just couldn’t believe that the bit of odd fat was actually omentum, or if you were unsure what you were looking at. You could also grab it (gently) and give it a little tug. If more comes out, you’ve made your diagnosis. Fortunately, this is rarely necessary because omentum has a very distinctive appearance. You know it when you see it.

What about probing the wound? One of my mentors, John Weigelt, used to ask, “Michael, does your finger / q-tip / instrument have an eyeball on the end of it?” His point was that probing is like so many other medical tests: diagnostic if positive, but unsettling if it’s not. What happens if the wound does penetrate, but you can’t find the path that the knife/bullet took? You can only call that indeterminate. I suppose you could take an approach that includes probing first, then proceeding to full LWE if that is negative.

I’ll describe the proper technique for local wound exploration in a later post.

And what about CT scan? This is another unsatisfying test, because it is very likely to be negative with small wounds. The fascial defect in this case will be very small, and can easily be missed on the scan. Not recommended.

Given all this discussion, my vote is to proceed to the operating room. I know this is omentum, and I know that there is a good likelihood that there will be an injury that needs repair. So let’s go get it done.  But what procedure should I do, and how should I do it? That’s the subject for my next post.

As always, please leave comments below or tweet them out!

 

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What Would You Do? Teensy Weensy Stab To The Abdomen – Part 2

Yesterday, I presented the case of a young man with a teensy weensy little stab to his abdomen, just above the umbilicus. There was a tiny bit of oddly colored fat that was visible in the wound. So now what should we do?

The first thing is to figure out what that bit of fat is. It doesn’t have the normal large pebbling and color of subcutaneous fat. Therefore, it must be a small piece of omentum protruding from the wound.

And what is the significance of that? This question has been addressed by papers with low numbers of subjects since the 1980s. It really depends on what country you are located in. Do you have readily available OR resources? Are there pressures to minimize hospital stays (US)?

One of the earliest papers originated from Parkland Hospital in Dallas TX. They reviewed 115 cases of omental evisceration over a 4 year period, and found that “serious” abdominal injuries were found in 75% of them. All went to laparotomy, and injuries to not one, but two organs were noted in about half of the positive cases. There was a 7% complication rate with negative laparotomy,

Contrast this with a study from Kingston, Jamaica where 66 patients with abdominal stabs and omental evisceration were treated. Of these, 14 were treated with observation because they had a normal abdominal exam. All were treated successfully without operation. But note the ratio here: 14/66 = 21%, which is the same as the negative laparotomy in the Parkland study (25%). So this study implies that if the patient can be watched and does not develop symptoms, the negative lap may be avoided.

Unfortunately, in many countries there are pressures to get people out of the hospital as soon as possible. Since small bowel content is relatively benign (at first), patients may not become symptomatic for several days. It would probably be difficult to convince your hospital to keep patients laying around for serial exams for days on end. Not to mention the logistical problems of doing good serial exams.

So most trauma professionals will be compelled to do something. And what should we do? Here are some possibilities. Pick your poison, and I’ll give you my choice tomorrow.

  • Local wound exploration
  • CT scan of the abdomen
  • Proceed to the operating room

As before, leave a comment to let me know what you would do. Or tweet it out!

References:

  1. Significance of omental evisceration in abdominal stab wounds. Am J Surg 152(6):670-673, 1986.
  2. Non-operative management of stab wounds to the abdomen with omental evisceration. J Royal Col Surg Edin 41(4):239-240, 1996.
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Best of AAST #10: Pediatric Contrast Extravasation And Pseudoaneurysms

There is a significant amount of variation in the management of pediatric solid organ injury. This is well documented between adult and pediatric trauma centers in t, but also apparently between centers in different countries. A poster from a Japanese group in Okinawa Japan will be presented this week detailing the relationship between contrast extravasation after spleen or liver injury and pseudoaneurysm formation.

In adults, the general rule is that pseudoaneurysms just about anywhere slowly enlarge and eventually rupture. This group sought to define this relationship in the pediatric age group. They performed a multi-center observational study of retrospectively enrolled children, defined as age 16 and less. Those who had contrast extravasation on initial CT were monitored for later pseudoaneurysm formation.

Here are the factoids:

  • 236 patients were enrolled across 10 participating centers, with about two-thirds having liver injury and the remainder with splenic injury
  • 80% of patients underwent followup CT scan (!!)
  • 33 patients (15%) underwent angiography (!!!!)
  • 17 patients with CT scan (2%) had pseudoaneurysm formation and 4 of them had a delayed rupture
  • Overall, pseudoaneurysms occurred in 29% of those with contrast extravasation and 5% without extravasation
  • The authors concluded that contrast extravasation was significantly associated with pseudoaneurysm formation after adjusting for variables such as ISS, injury grade, and degree of hemoperitoneum

Bottom line: This is an abstract, so a lot is missing. What was the age distribution, especially among those who underwent angiography? Was the data skewed by a predominantly teenage population, whose organs behave more like adults? The abstract answers a question but ignores the clinical significance.

For those trauma professionals who routinely care for pediatric patients, you know that contrast extravasation in children doesn’t act like its adult counterpart. Kids seldom decompensate, and for those who are mistakenly taken for angiography, the extravasation is frequently gone. The authors even admitted in the conclusion that aggressive screening and treatment for pseudoaneurysm was carried out.

The real question is, what is the significance of a solid organ pseudoaneurysm in children? Based on my clinical experience and reading of the US literature, not much. Of course, there is a gray zone as children move into adulthood in the early to mid-teens. But this does not warrant re-scanning and there should be no routine angiography in this age group. Contrast extravasation in pediatric patients warrants close observation for a period of time. But intervention should only be considered in those who behave clinically like they have ongoing bleeding. 

Reference: Association between contrast extravasation on CT scan and pseudoaneurysm in pediatric blunt splenic and hepatic injury: a multi-institutional observational study. Poster 31, AAST 2018.

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