Category Archives: Extremity

What A MESS! Part 2

The trauma season is always officially open. And unfortunately, our patients can sustain mangled extremities in any number of ways. In days of old, management was simple: take it off. But we’ve become wiser over the years and are now able to salvage a good number of these threatened limbs. The Mangled Extremity Severity Score (MESS) has helped greatly with this. 

As I mentioned yesterday, it’s beginnings were humble, almost looking like guesswork on the part of the authors. But this system has withstood the test of time.

There are four components to MESS: limb ischemia, patient age, presence of shock, and mechanism of injury. Each component is assigned an integer value depending on severity. The possible values range from 1 to 14. Here’s the breakdown of each component:

Ischemia

  • +1 Reduced pulse but normal perfusion
  • +2 Pulseless, paresthetic, reduced capillary refill
  • +3 Cool, paralyzed, insensate
  • Add 3 points if limb ischemia has been present more than 6 hours

Age

  • +0   <30 years
  • +1   30-50 years
  • +2   >50 years

Shock

  • +0 SBP >90 consistently
  • +1 Transient hypotension
  • +2 Persistent hypotension

Mechanism (kinetic energy)

  • +1 Low (stab, gunshot, simple fracture)
  • +2 Medium (dislocation, open or multiple fractures)
  • +3 High (high speed MVC, rifle)
  • +4 Very high (high energy trauma with gross contamination)

Per the original study, values of 7 or greater predict low salvageability. However, with advancing technology, drugs, and operative techniques, the threshold has been creeping higher. But not that much higher, probably 8 or so.

Bottom line: Use the MESS score as one tool in your armamentarium to help address mangled extremities. But remember, it is not the final answer. In the OR, confer with your orthopedic and vascular colleagues. Decide if immediate amputation is necessary, or whether a second look in a day or two is in order. Use MESS as a tiebreaker. But remember, don’t let your desire to save the extremity jeopardize your patient’s life (rhabdomyolysis, renal failure, acidosis). If systemic signs begin to occur, cut your (and their) losses and amputate!

Related post:

Print Friendly, PDF & Email

What A MESS! Part 1

The Mangled Extremity Severity Score (MESS) is now 25 years old, and it still serves us fairly well. This simple system helps predict salvageability of mangled extremities. Obviously, the acronym was chosen to help describe the clinical problem.

The system was originated at the Harborview Medical Center in Seattle. The development was not very scientific; the authors put their heads together and made a list of the four things that they observed predicted limb salvage:

  • Degree of skeletal and soft tissue injury
  • Presence of limb ischemia
  • Presence of shock
  • Age

The system was used retrospectively in a group of 25 patients(!) and the authors found a nice breakpoint at 7. Any mangled extremities with a MESS of 7 or more required amputation. They then applied this to 26 patients prospectively(!) and got the same result.

As you can see, the numbers were small, and there was no followup information. Nevertheless, MESS still stands today, and the critical MESS score has not changed much. It has been validated by a number of other studies during the past 20 years. It is conceivable that the critical score will slowly creep upward with advancements in flap coverage and surgical technique, but it hasn’t done so yet.

Tomorrow, I’ll show you how to calculate the MESS score, and give some tips on how to use it.

Reference: Objective Criteria Accurately Predict Amputation Following Lower Extremity Trauma. Johansen, et al. J Trauma 30(5): 568, 1990.

Print Friendly, PDF & Email

Practical Tips: Transferring The Mangled Extremity

Managing the mangled extremity is both challenging and intense. There is always pressure to do all we can to save that threatened limb. But as you know, different levels of trauma centers have different capabilities and specialists that are needed to fully manage these injuries.

Level I centers have a comprehensive set of specialists to deal with the managed extremity, including trauma surgeons, vascular surgeons, orthopedic surgeons comfortable with complex injury, plastic surgeons, and interventional radiologists. The expectation is that a mangled extremity can be completely managed at such a center.

Level III centers have much more limited resources, and may only have a trauma surgeon to perform the initial evaluation. Definitive management can only occur after transfer to a Level I center.

Level II centers often find themselves in a kind of limbo. They have most of the specialties required, but those specialists may have varying comfort levels regarding addressing complex injuries. Some Level II centers may be able to keep these patients, but many will find that they need to transfer to their upstream Level I partner.

What do transferring trauma centers need to do before actually moving the patient? Here are some practical tips.

  • Evaluate quickly. The bottom line is to try to preserve function, so time is of the essence. Do a thorough evaluation of the anatomy, as well as vascular and neurologic status. These are the major determinants of salvageability.
  • Don’t ignore the rest of the patient. Make sure that injuries more critical than the extremity are identified and addressed. See the “Dang Factor!” below.
  • Make a decision. Now. Decide whether you need to transfer the patient based on your knowledge of your consultants’ skill levels and comfort.
  • Once you decide you will transfer, do no further imaging. It’s not going to change anything you do, and may not be very helpful to the receiving center.
  • Give IV antibiotics and the life-saving tetanus shot early.
  • Optimize salvageability. Do what you can to keep tissue healthy during the transfer. You must take transfer time into account for this! If you are sending your patient across town, just do it quickly. However, if he or she must travel long distance, there are a few more things to consider:
    • Try removing the tourniquet (if any). You’d be surprised at how many times the bleeding has stopped already. Or maybe wasn’t needed in the first place.
    • Selectively try to control bleeding if possible. Carefully ligate small vessels if you can. Don’t clamp and tie large masses of tissue.
    • Consider a vascular shunt. If there is an obvious large vessel injury, and if you have a trauma or vascular surgeon who is comfortable with inserting a vascular shunt, do it prior to transfer. This will increase the likelihood of salvage in long-distance transfers. But don’t waste a lot of time doing this! If you can’t get it done within about 30 minutes or so, don’t delay the transfer.
    • Quickly rinse off the area. Try to minimize the time that noxious stuff (dirt, gasoline, etc) is in contact with the tissues.
    • Splint well. You’ll need to be creative. But you don’t want additional tissue injury due to the extremity just flopping around.
  • Inquire about followup. Find out how the patient did, and discuss anything you could have done differently with the receiving center. As always, performance improvement is important!

Related posts:

Print Friendly, PDF & Email

ABI vs API For Vascular Trauma

In general, the first maneuver in evaluating for possible vascular injury in an extremity is the good old physical exam. Is there a pulse or isn’t there? You can then subdivide that into: is the pulse weaker than normal. The problem is, what is “normal?” In most cases, we just compare it to another pulse somewhere and make a subjective judgment.

But we love to be more objective about things. Over the years, two simple, noninvasive techniques for evaluating pulses have been developed. The first is the ankle brachial index (ABI) , which was first described in 1930 and was used for diagnosis of peripheral vascular disease in 1950. It is performed by dividing the systolic pressure at the ankle of the affected extremity by the systolic pressure of one of the brachial arteries in the arms.

The new(er) kid on the block is the arterial pressure index (API), first described in 1991. This value is calculated by dividing the systolic pressure in the affected extremity by the systolic pressure in the contralateral uninjured extremity.

Many trauma professionals use the ABI when evaluating for potential vascular trauma. The typical threshold for pursuing further evaluation is 0.9, and several papers have been published on this topic. The API has also been critically evaluated, and the same threshold is used.

However, I believe that the API is more relevant and accurate than ABI. Why? Patients with atherosclerotic disease typically manifest it in their lower extremities. This serves to falsely elevate the ABI to a value greater than 1.0. It becomes more difficult to get down to that critical value of 0.9 that might indicate a vascular injury. Thus, the ABI may not detect a true injury, especially one in the lower extremities.

The API, on the other hand, relies on the fact that the amount of atherosclerotic disease is usually symmetric between the two lower extremities or the two upper extremities. Thus, the value will not be falsely elevated and will more accurately reflect the presence or absence of a vascular injury.

Bottom line: I recommend that you use the API when evaluating extremity vascular injury. Calculate the ratio by dividing the systolic pressure in the injured extremity with the pressure in the contralateral uninjured extremity (if there is one). A value < 0.9 indicates the need for angiographic evaluation, usually by CT scan.

And here’s a nice algorithm for managing peripheral vascular trauma from Life in the Fastlane:

Reference: Can Doppler Pressure Measurement Replace “Exclusion” Arteriography in the Diagnosis of Occult Extremity Arterial Trauma? Ann Surg 214(6):737-741, 1991.

Print Friendly, PDF & Email