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How Good Is The Spine Exam In Penetrating Injury?

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Examination of the spine in trauma patients is typically not very helpful. We always look for stepoffs. swelling and tenderness, but the correlation with actual injury is poor. A recent paper presented at the American Medical Student Association Annual Convention showed that it actually can be helpful in victims of penetrating injury.

A prospective study of 282 patients was carried out at a Level I Trauma Center, specifically focusing on penetrating trauma. Half had gunshot wounds, and 8% sustained spinal injury with one third left with permanent disability. Stab wounds never led to a spinal cord injury. The most common patterns for cord injury in gunshot wounds was a single shot to the head or neck, or multiple shots to the torso.

The examiners looked for pain, tenderness, deformity and neurologic deficit. They found that the sensitivity was 67%, the specificity was 90%, the positive predictive value was 95% and the negative predictive value was 46%. These numbers are much better than those found during spine examination after blunt trauma. They also determined that prehospital immobilization after penetrating injury would not have helped, which I have also written about here.

Bottom line: A good spine exam in victims of penetrating trauma can accelerate definitive management prior to defining the exact details of the injury with radiographic or MRI imaging. This is particularly helpful in patients who present to non-trauma centers, where imaging or image interpretation may not be readily available.

Reference: American Medical Student Association (AMSA) 60th Annual Convention: Abstract 26: Presented March 11, 2010

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Knife To The Back! Part 2

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Yesterday, I presented a case of a young man with a knife in his back. He was brought to your ED in the prone position. The question was, what to do next?

With any trauma patient, regardless of size, shape, or position, the first question is always, “does this patient belong in the ED?” And usually, that question is answered by checking hemodynamic stability.

This patient stays prone while you quickly assess vital signs. If vitals are abnormal, he needs to get rolled to the operating room immediately, while still prone. There is no time to figure out how to reposition, or if the knife can be removed. Get him out of your ED.

But let’s say he is hemodynamically normal and talking to you. You need more information. So start with a physical exam. With him in the prone position! It works. In this case, there are no other puncture wounds, and the anterior part of the body can be examined by carefully logrolling him onto his side. Breath sounds are decreased over the right chest, otherwise there are no other anomalies.

So now what? Well, let’s get some more info! How about a chest xray? Best position? Prone! It’s the easiest, because the patient does not need to be held up next to an xray plate, which would also have to be held manually. The lateral view doesn’t add anything but hassle. Here’s the result:

Now what? What do you see, what do you do? Tweet or comment; more to follow tomorrow.

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When Can You Close That Stab Wound?

I find that many trauma professionals are nervous about closing stab wounds. They seem to worry a lot about infections and lean toward leaving the wound open to heal by secondary intention. But is this warranted?

The answer is: probably not. Most knives used for assaults are clean, but not quite sterile. Yes, there are a few bacteria on the blade, but not very many. So if the usual wound management guidelines are followed, the patients generally do quite well. 

The guidelines are:

  • No gross contamination. If the knife was used to cut raw chicken or to stir up manure, that’s a problem. Leave it open.
  • No devitalized tissue. Complex lacerations with dusky skin bridges may get infected. Debride or leave open.
  • Don’t let the wound get fully colonized with skin bacteria. There is no good literature on this, but more than 12 hours for most of the body and 24 hours for the face is a reasonable guideline.

If any of these guidelines have been violated, it’s probably best to leave the wound open. Otherwise the default should be to try to close it as soon and as cleanly as possible. This means irrigating with saline to decrease any bacterial counts. Either sutures or staples are acceptable.

The most important part of this process is patient education. They must be informed about what signs of a wound infection to look for so they can return earlier rather than later to have you deal with it.

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Retained Foreign Objects After Penetrating Injury

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Recently, a Chinese man was in the news after having a four inch knife blade removed from his head after four years. What is the best way to deal with a problem like this?

First, get in the habit of imaging any body part with a penetrating injury. Retained objects can be as simple as gravel or as complicated as the knife blade above. And remember, some patients who have been stabbed present with a simple laceration but don’t want to tell you how they got it. Image before you close it!

Next, don’t remove it. This is common knowledge, but innocent looking objects (pencils, nails) can penetrate arteries and keep them from bleeding while embedded. Unpleasant and sometimes fatal bleeding can ensue if pulled out.

If you do not have specialists versed in the body regions involved in the injury, transfer immediately with the object secured in place. For objects penetrating minimally complex areas like the extremities, surgeons may opt to carefully remove it in the emergency department, or may elect to do so in the operating room.

Injuries to complex areas should undergo high resolution CT scanning so that 3D reconstruction can be performed if needed. The surgical specialists can then plan the operative approach. This is dictated by the anatomy of the area(s) involved and the architecture of the object (think about hooks and barbs). For objects located near critical areas, an operative exposure must be selected that provides access to all portions of it, and allows for rapid vascular control if needed.

This patient had a knife blade break off after he had been stabbed under the chin. It remained partly within the nasopharynx and the tip came to rest behind his left eye. His symptoms included headaches, stuffy nose and bad breath. The picture below shows the badly corroded blade in front of some of his radiographic images.

Knife in head

(Source: http://c.brightcove.com/)
General

How To Read A Stab Wound

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Most emergency departments do not see much penetrating trauma. But it is helpful to be able to learn as much as possible from the appearance of these piercing injuries when you do see them. This post will describe the basics of reading stab wounds.

Important: This information will allow some basic interpretation of wounds. It will not qualify you as a forensics expert by any means. I do not recommend that you document any of this information in the medical record unless you have specific forensic training. You should only write things like “a wound was noted in the midepigastrium that is 2 cm in length.” Your note can and will be used in a court of law, and if you are wrong there can be significant consequences for the plaintiff or the defendant. This information is for your edification only.

1. What is the length of the wound? This does not necessarily correspond to the width of the blade. Skin stretches as it is cut, so the wound will usually retract to a length that is shorter than the full width of the blade.

2. Is the item sharp on one side or both? This can usually be determined by the appearance of the wound. A linear wound with two sharp ends is generally a two sided knife. A wound with one flat end and one sharp end is usually from a one-sided weapon. The picture below shows a knife wound with one sharp side.

Single edge knife wound

3. Is there a hilt? This can usually be detected by looking for bruising around the wound. The picture below shows a knife wound with a hilt mark.

Knife wound with hilt mark

4. What is the angle? If both edges are symmetric, the knife went straight in. If one surface has a tangential appearance, then the knife was angled toward that side. You can approximate the direction of entry by looking at the tangential surface of the wound edge.

Angled knife entry

5. How deep did it go? You have no way of knowing unless you have the blood stained blade in your possession. And yes, it is possible for the wound to go deeper than the length of the knife, since the abdominal wall or other soft tissues can be pushed inwards during the stab.