This case was inspired by Dr Anand Swaminathan out of New York. Anand recently uploaded a JAMIT video tutorial on the “tongue-blade test” for mandible fractures.
In case you have never heard of this or never actually tried it – check out the video here first. A cool 1-minute demo and discussion. From the twitter comments that followed – you might want to use the test with a pinch of salt in the very drunk, super tough or stoic patient.
Here is the case for today:
28 y.o. man presents to the ED at 0300 from a local nightclub. He was negotiating his involuntary departure from the said facility with one of the security officers when he suffered a single punch to the left side of the jaw – the bouncer was a righty!
He then proceeded to the local kebab / souvlaki / burger / dim-sim / insert take away of your choice… to get a consulatatory snack. He tried to open his mouth to bite the kebab and found he could not bite with any force and had a heap of pain in the left jaw. So he wandered onto ED for a check up…
Of course, it is Broome. It is 3 AM and there is no radiology department – just you and your trusty US probe.
Here is what he looks like….
It is tough to examine his bony structures clinically as there is a healthy padding of adipose tissue blocking your clinical acumen. There is a bit of swelling overlying the angle of the left mandible.
So – you try and open his mouth – he can only get about a centimetre between his incisors. There is a bit of blood in there. HE states that his lower tooth feels a bit wobbly when he probes it with his tongue.
He has no other injuries.
So – does he have a broken jaw? Do we need to get him to a MaxFac surgeon for an ORIF? Or can we just let him go? Maybe bring him back in the morning for an Xray??
He doesn’t seem like a really reliable candidate for outpatient therapy!
So you dial up Dr Anand’s JAMIT video on the Tongue-blade test.
Unfortunately it is not negative…. so what does that mean? Well the Tongue-blade test has a really good negative likelihood – so if it is normal, great, he probably has no fracture. Here are a few links to posts on evidence for the utility of the TBT: Bestbets, EMlitof Note, ALIEM
But a potent -LR means that it has a poor specificity. So there are other reasons that it might be positive.
So – next move….. bedside Ultrasound of course.
Mandibles are superficial bones, easily accessible. So we can scan them – but what does the evidence say about our diagnostic accuracy with the probe?
Well – there is not a lot of high quality stuff, but I found this systematic review out of Nigeria. Int J Oral Maxillofac Surg., 2011.
Basically there is a wide range of accuracy reported – but as is often the case with US – it is more specific than sensitive – that is to say – better for ruling in a fracture than ruling out.
So this is interesting. If you take out “tongue-blade test” with high sensitivity and add in an US with high specificity – I think you might have a winning combination. So I think I am going to start using this as a “2 punch” diagnostic strategy in the wee hours of the night when I need to make a call on the risk. Send home, or admit for transfer.
Let me know what you think… or let Anand know on Twitter @EMSwami
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