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 and send him over to the Dental Implants Beverly Hills office for the required new tooth/teeth?
He doesn’t seem like a really reliable candidate for outpatient therapy!
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?
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
I am a GP working in Broome, NW of Western Australia. I work as a hospital DMO (District Med Officer) doing Emergency, Anaesthestics, some Obstetrics and a lot of miscellaneous primary care. Also on the web as @broomedocs | + Casey Parker | Contact