I about a patient I saw who, having bounced his Harley
off the side of a pick-up truck, sustained (among other things) a
hangman's fracture, or, more properly, a fracture of both partes
intraarticulares of the C2 pedicle:
It's funny how people react to
an injury called the "hangman's fracture." The sentiment I
encountered most commonly from the other health care providers involved
in this patient's care was "holy crap!" It's not that we didn't
expect this patient to have significant injuries -- quite the
opposite. But there's a sense that if he's got a Hangman's fracture,
it must be really bad, right?
Not so much, it turns out. I hate eponyms, and this is a great
example of why. In my career, working at several different trauma
centers, I have seen dozens of these injuries, and without exception,
they have all been neurologically intact. So, one might wonder, why
is it that such an (apparently) benign injury has such a scary name?
It's all about mechanism. This fracture results from forced
hyper-extension of the neck; the occiput slams backwards and down on the
spinous process of C2 (and C1) and essentially knocks the posterior
structures off of the body of C2. This fracture was named in the
distant past, when the most common mechanism was judicial hanging.
Hanging had been distilled down to a science by the late nineteenth
century, especially in England where it was used frequently at Tyburn
and Newgate. The "long drop" method of execution had been found to
reliably cause instant and supposedly painless death, rather than the
prolonged agonies, and occasional survivors, of short-drop lynchings.
The English authorities developed charts based on the weight of the
condemned which dictated the amount of drop to pitch the accused without
causing decapitation -- typically a 5 to 9 foot drop, to result in 1,000
pounds of force was optimal. The placement of the knot was critical -- under the
chin and to the left -- in order to produce the abrupt and forceful
hyper-extension and the lethal high spinal cord injury. Were the knot
placed posteriorly, the force would rather be directed at the trachea,
jugulars, and carotids, causing slow death from asphyxia. The executed
were routinely autopsied to evaluate the efficacy of the execution
process (gruesome fact: they measured the amount the neck stretched
after executions, on average one to two inches). See here for an
example post mortem report, with the classic finding of the C2 fracture.
So why are modern "Hangman's" so survivable?
Hanging, if you think about it, is an axial load in distraction. The
majority of the current cervical fractures occur due to axial loading
in compression. Imagine a frontal MVA, with the driver's head
impacting the windshield in extension:
Or a diver's head striking the bottom of a swimming pool, or a
linebacker spearing a running back. It's almost always in
compression. A compressive force will knock off the posterior
elements of the spinal coumn, but this actually widens the space for
the spinal cord. But a distractive force, while also causing the
characteristic posterior injury, additionally tears the anterior elements of the
spine, rotating the body of C2 as below, thereby crushing and transecting the
spinal cord.
So although the two types of fractures are anatomically identical, they
are quite disparate in their associated injury pattern and clinical
significance. The take-home message? We all love the drama and
excitement of a "Hangman's" fracture, but don't be "distracted" by the
name -- pay attention to the mechanism. In most cases, it's not as
bad as you might think.