Archive | Articles RSS feed for this archive

Student Corner: Ottawa Ankle Rules

October 14, 2014

0 Comments

The Ottawa Ankle Rules are a set of criteria that are designed to help clinicians identify which patients that present with acute ankle injuries require imaging. The 1992 paper which outlined the criteria (PMID:1554175) consisted of a prospective study of 750 patients who came into the Ottawa Civic and Ottawa General hospitals with acute ankle injuries. The study was designed to record each patient’s particular presentation (area of tenderness, amount of swelling, ecchymoses, etc) and see if any aspect of their presentation correlated with a fracture identified on subsequent imaging (i.e. if a patient has pain over the medial malleolus, how likely are images of that ankle to show a fracture?).

MD Calc has a good summary picture of the criteria here. I’ll summarize it below as well:

A series of ankle x-rays is necessary if:

There is tenderness in the malleolar zone (lateral or medial) AND bony tenderness at the posterior edge of the medial malleolus OR bony tenderness at the posterior edge of the lateral malleolus OR an inability to bear weight immediately and in the ED

OR

There is tenderness in the midfoot zone AND bony tenderness at the base of the 5th metatarsal OR bony tenderness at the navicular OR an inability to bear weight immediately and in the ED

The picture on the link above is probably more helpful to visualize the algorithm. They note that 102 patients out of the 750 cohort had “significant” fractures and these criteria would have led to imaging on all of those cases. Also, they report that this criteria would have led to a 32.3% decrease in the number of radiographs ordered. The algorithm’s sensitivity was 100% and specificity was 40% for identifying fractures that were later confirmed by imaging. In other words, it was touted as a great screening tool since it was highly sensitive in picking up an ankle fracture.

(Note: The original criteria included an age stipulation, so that every patient with ankle pain [but not midfoot pain] over the age of 55 was recommended to get imaging. Additional research and subsequent modification of the algorithm proved that age was actually not a predictive variable. [PMID: 8433468])

Now on to a case:

Homeless male, in his 50’s, with ankle and foot pain after falling 10 feet. Walked into the E.D. with some pain, but had the ability to bear weight. Pt had swelling on exam, but no tenderness at the lateral malleolus, medial malleolus, mid foot or lateral foot.

The question is, do you get imaging on this patient?

Oh, look, it turns out we have criteria for that! And, in short, if you follow the Ottawa Ankle Criteria, the answer is no. The patient can bear weight and has no tenderness at any of the 4 areas that the criteria specifies, therefore according to the algorithm, imaging should not be ordered.

But we have a twist! This patient did indeed get ankle x-rays.

Ottawa Ankle 1

Why did this patient end up getting ankle x-rays despite not having met the Ottowa Ankle criteria?

Dr. Jones plays “devil’s advocate” in arguing against the use of the Ottowa Ankle Rules:

“Despite high negative likelihood ratio’s found on creation and validation of the Ottowa Ankle Rules, ED physicians are still ordering x-rays for most traumatic ankle complaints.  Why?  Because they are immediately available, low cost, and low radiation.  Many of our radiology decision rules pertain to expensive tests that are 10-100 times the amount of radiation (CT head, CT c-spine) and/or may not be readily available.  It is less practical to try and decrease a test that has little downside…such as an ankle radiograph.  

There is usually significant comorbidity associated with many different types of ankle fractures including calcaneal and talar fractures (I mention these because in my experience these are the two fracture patterns that are missed by the Ottowa Ankle Rules despite their reported 100% sensitivity…see the case above).  In our medicolegal environment in the United States, it is very difficult to defend missing an ankle fracture when you have a low cost, low radiation, readily available test at your disposal.  One must take into account that it is nearly impossible to recreate an exam with our current medical documentation.  A radiograph is an objective picture of a non-fractured ankle while a nicely worded exam is not so defendable in the eyes of a layman jury.  You open yourself up to legal problems if you miss a high-morbitidy injury because you used a rule that “decreases medical costs and increases efficiency” (these are the main benefits of the Ottowa Ankle Rules).  Courts are more patient-centered, they don’t care about our waiting room times!

We practice medicine taking into account more than just evidence-based medicine.  Until the “standard of care” we are held up to in court is in line with evidence-based medicine, we will always have to take into account the burden of the medicolegal consequences.  Be careful utilizing any clinical decision rules until they are universally accepted as standard of care among all ED physicians.  

I personally use “shared decision making” with most of my decision rule utilization.  My practice pattern using Ottowa Ankle Rules involves (1) A medical record documenting negative Ottowa Ankle Rules AND (2) a patient that understands the decision not to x-ray AND (3) the patient agrees.  This situation is rare but I will sometimes not x-ray if all the above parameters are met.  This is easier to defend if you happen to miss something by not getting an x-ray.  

The above statement is of course my own opinion and practice pattern.  Please utilize the Ottowa Ankle Rules as you feel fit and I appreciate any comments for and against their use in the ED.    

Russell Jones, MD”

So, there you have it. As is the case with many different areas of medicine, real-life practice varies from guidelines, rules and algorithms (even if they are backed up by multiple research studies) for various different reasons which include, but are not limited to differences in: availability of testing methods, medical setting, hospital policies, patient needs, legal considerations and the physician’s own interpretation of all of the above factors and the medical research/literature.

For students, this means that you’ll have to soon adapt yourself to an environment and way of thinking that takes multiple variables into account when it comes to decision making. Almost every patient is a different shade of grey, not black and white. After all, medicine is both art and science.

But, I digress from the patient. Can you spot the fracture in the above image? Answer below:

Calcaneal fracture with arrow

 

There is indeed a fracture of the calcaneus right around the inferior edge of the bone. Good thing this patient got imaging, right?

Author: Jaymin Patel

References:

Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Worthington JR. A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Ann Emerg Med. 1992 Apr;21(4):384-90. PubMed PMID: 1554175

Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Reardon M, Stewart JP, Maloney J. Decision rules for the use of radiography in acute ankle injuries. Refinement and prospective validation. JAMA. 1993 Mar 3;269(9):1127-32. PubMed PMID: 8433468.

Advertisements
Continue reading...

How to identify a cardiac rhythm device with CXR…

September 25, 2014

0 Comments

How many times have you had trouble with figuring out what type of cardiac device (e.g. pacemaker/defibrillator) a patient has implanted?  A patient presented to our ED with chest pain, palpitations.  He did not have his device card with them, no prior visits to our ED, and did not know the manufacturer of the device.  How do you decide which company to call for interrogation?

Here is an article I found with radiologic characteristics of devices that can help identify which company produced the device.  It has a great identification algorithm they coined the CaRDIA-X algorithm:

http://www.ianchristoph.com/physician-resources-2/device_id.pdf

There are 5 major manufacturers currently:  Medtronic, Boston Scientific, St. Jude, Biotronik, and Sorin Group.  Each device manufactured by these companies have certain differentiating characteristics of can shape, battery shape, alphanumeric codes, capacitor shadows, coil types, etc.  Turns out you can identify the manufacturer using the device characteristics on chest X-ray relatively easily.

In the case I was describing above the patient had an easily identifiable Medtronic device and we were able to get it interrogated.  Our ED now has the algorithm posted at our doctor’s station so we can utilize it for device identification.

Author:  Russell Jones, MD

References

Jacob S et al.  Cardiac Rhythm Device Identification Algorithm Using X-Rays: CaRDIA-X.  Heart Rhythm 2011; 8(6): 915-922.

Continue reading...

Stabbed in the chest…

January 29, 2014

0 Comments

This patient was stabbed in the chest multiple times.  Markers showing the external stab wounds to the lateral chest wall on the right side:

HemoPTX stabbed

This is a classic trauma chest xray with a hemopneumothorax on the right side.  This patient has a great indication for a large-bore chest tube!  Not only to reexpand his lung but to monitor hemothorax output and need for emergent thoracotomy to evaluate the source of bleeding.  Trauma recommendations from the Journal of Trauma in 2010 concerning hemothorax include:

1.  Patient physiology should be the primary indication for surgical intervention rather than absolute numbers of initial or persistent {chest tube} output (Level I recommendation)

2.  1500 ml via a chest tube in any 24-hour period regardless of mechanism should prompt consideration for surgical exploration (Level II recommendation)

3.  All hemothoracies, regardless of size, should be considered for drainage (Level III recommendation)

Please see the EAST Trauma Guidelines for further details:

Mowery NT, et. al.  Practice Management Guidelines for Management of Hemothorax and Occult Pneumothorax.  J Trauma 2011; 70 (2): 2011. 

Author:  Russell Jones, MD

Continue reading...

Is the shunt series a dinosaur?

September 10, 2013

0 Comments

When a patient with a ventricular shunt presents to the ED, many times we will obtain a “shunt series.”  What is a “shunt series?”  Here is an example:
Shunt 1Shunt Series 2 Shunt series 3

The top image shows a lateral cranial view demonstrating the intracranial portion of the shunt (#1), the shunt reservoir and valve (#2), and a portion of the extracranial portion of the shunt catheter coursing down the lateral portion of the head.  The second image is an AP cranial radiograph.  This is another view of the shunt with the advantage of better imaging of the lateral extracranial catheter coursing down the neck and upper chest.  The third image is an AP abdomen which shows the rest of the catheter’s course into the abdomen.

How are these used?  Shunt series are used to look for kinks and breaks in the course of the catheter, most often the extracranial portion.

There is controversy whether we should use our time, expense, as well as the radiation to obtain shunt series.  Their yield is very low and CT imaging of the head or nuclear medicine shuntograms are much better at detecting shunt failure.  One series of 263 patients showed that less than 1% of shunt revisions were based on the findings on the shunt series (1).  Another study in 2011 demonstrated a lack of statistical significance in shunt series and surgical revision.  CT and nuclear medicine imaging, on the other hand, showed statistical correlation with shunt revision (2).

Kinda begs the question:  should we be obtaining shunt series at all?

References

1.  Griffey RT, Ledbetter S, Korasani R.  Yield and utility of radiographic “shunt series” in the evaluation of ventricle-peritoneal shunt malfunction in adult emergency patients. Emerg Radiol 2007; 13 (6): 307-11.

2.  Lehnert BE, et al.  Detection of ventricular shunt malfunction in the ED:  relative utility of radiography, CT, and nuclear imaging.  Emerg Radiol 2011; 18 (4): 299-305.

Continue reading...

Cost Transparency doesn’t reduce testing…

February 11, 2013

0 Comments

Would physicians order less tests if they knew the cost?  Researchers in the Department of Radiology at John’s Hopkins say no.  This month’s issue of the Journal of  American College of Radiology includes a study on the subject:

Durand DJ, Feldman LS, Lewin JS, Brotman DJ.  Provider cost transparency alone has no impact on inpatient imaging utilization.  J Am Coll Rad. 2013 Feb;10(2):108-13 PMID:  23273974

Quick Summary:

The study used retrospective data to identify 10 of the most-utilized radiology tests in their institution.  During a baseline period they measured imaging utilization in a control and an active group.  During the intervention period (which was seasonally matched) they showed the cost of imaging to the active group prior to test utilization.  They measured a mean utilization change between groups and found that there was no statistically significant difference between groups.  They concluded that showing physicians the cost of the test doesn’t dissuade them from utilizing the imaging.

My Thoughts (not to be taken as the expert opinion!):

This is an interesting article that can lead some to believe that physicians don’t care about the cost of imaging.  It strikes a subject that is very “sexy” in the news due to the ever-rising cost of healthcare.  It is no mystery that imaging utilization is increasing on a yearly-basis and at some point the cost to society may outweigh the benefit.  However, in today’s litigious society physicians aren’t willing to risk misses and not utilize imaging capability that is literally in the next room.  I unfortunately don’t have a solution.  However, this article suggests that putting a price tag in front of us is not the answer.

Perhaps the regulatory control agencies can solve the problem (I just chuckled a bit).  In 2012, Centers for Medicare and Medicaid Services (CMS) decided to run a “dry run” measure of ED Head CT usage in non-traumatic headache.  I haven’t heard of the results yet, has anyone else?

Author:  Russell Jones, MD

Continue reading...