The following case study is of a friend of mine (written with his permission) who was shot through the neck by an AK-47 during an operation from a range of about 150 meters. The bullet entered the back of his neck just right of the midline and then blew out the front of the left side of his neck. Remarkably, he not only survived, but has subsequently made a near-complete recovery, and has conquered both the North and South Poles on foot! This case study is fascinating from both a terminal ballistics perspective, as well as from a medical perspective regarding the immediate and delayed effects of the temporary cavitation, or pressure wave, emanating from the high-velocity bullet as it passed through his neck.

Those of you who have read my previous article on why I’d rather be shot by an AK-47 than a M4 will already understand the concept of permanent versus temporary cavitation, and the basics of the theoretical differences in wounding profiles between the AK-47 and the M4. I think it’s worth a read. The key concept from that article that relates to the current case study is the tendency for an AK-47 round to remain intact and generally plough straight through short distances of human tissue before it destabilises and starts to yaw, or tumble. Should the bullet not hit any bone, the result is often a nice clean through-and-through wound, which is exactly the instance in the current case study.

In that setting, assuming the bullet hasn’t passed through any vital structures, the permanent cavity left by the bullet is akin to sticking a sharp stick through the casualty. This brings me to my first set of images, which show the neat hole punched through the casualty’s neck. The first image was taken on the day of the injury, with the remainder of the images taken the day after the incident, and illustrating the near perfectly circular exit wound of the bullet, only slightly larger than its 7.62mm diameter. The bullet had traversed approximately 15 cm (six inches) of tissue, and I suspect if the round had been from a M4, the outcome may have been dramatically worse (once again, covered in my previous article).

Even more interesting than the images above are the CT images depicting the path of the bullet through the casualty’s neck.

I’m by no means an expert at interpreting CT scans, but as a basic orientation to these images, we are looking at a slice through the casualty’s neck at the level where the bullet passed through. As can be seen in the initial images, this is at the level of his mouth and tongue. When looking at a CT slice, it is as though you are looking up from the feet of the patient, so what you see on the right of the image is actually the patient’s left. The first thing to appreciate is the swelling caused by the trauma of the bullet causing the tissues on the left side of the casualty’s neck (right side of the image) to bulge out when compared to the other side.

The white part at the center of the image is the vertebra at that level, with the dark semi-circular structure at the center of it being the spinal cord. The medically initiated will pick up on the fact that a small chip of bone has been taken off the back of the vertebra, or the spinous process. So in effect, the casualty had a broken neck, which has implications for the first responder in moving him around during his management and evacuation. As we’re all taught, if a spinal injury is suspected, the casualty should be kept as still as possible in case the injury is unstable and movement could damage the spinal cord, potentially causing paralysis.

This approach is fine for most civilian contexts, however in examples such as this one where there was an ongoing tactical situation, the priority is always to reduce the threat and move the casualty to a safe location immediately, with minimal regard for spinal precautions. While there is always a possibility of an unstable cervical spine injury following penetrating trauma, it is generally accepted that the risk is very low (<1 percent) (Lustenberger et al.  2011). Furthermore, even if the cervical spine is unstable following a gunshot wound, the spinal cord can still remain perfectly intact (Apfelbaum & Waldman 2000).

These next images show the path of the bullet through the neck, and the vital structures that the bullet somehow didn’t disrupt. Also included is an anatomy slide taken from the Internet, showing the gross structures at roughly the same level for comparison. In the first image, the path of the bullet can be seen by the small pockets of air drawn into the tissues as the bullet passed through, which appear black on the CT image. A blue line has been drawn along the bullet’s rough path to illustrate. The next image was taken after a dye was injected in the casualty’s veins, which pumped around his blood vessels, causing them to appear white on the CT scan.

Mentally superimposing the path of the bullet, it can be seen that it passes directly through a rather large pipe in the front of the casualty’s neck, which I assess as being the internal jugular vein. (I’m very happy to be corrected by any radiologists out there!) Immediately next to the internal jugular vein is an even more important structure, the internal carotid artery, which, had it been disrupted, would have almost certainly resulted in the death of the casualty given the circumstances on the day. Miraculously, neither of these major blood vessels were damaged, with the only rational explanation offered by the treating surgeon being that the bullet simply pushed them aside. Once again, in my opinion, were this to have been a M4 round, I suspect the outcome would have been dramatically worse.

So far I have only considered the damage done by the permanent cavity caused by the bullet, which both fractured the spinous process of the casualty’s vertebra and punched through the exact location of his major neck blood vessels without disrupting them. Of more medical significance, both on the day and ongoing since, was the damage done by the temporary cavitation of the bullet as it passed through. Those who have read my previous post (or have a good grasp of the subject) can disregard the following video, but for those who haven’t, the following YouTube video by Brass Fetcher demonstrates the pressure wave generated by a 7.62x39mm bullet when it passes through tissue. In the video, a bullet is shot into ballistic gelatin that has roughly the same density as human tissue. The pressure wave seen disrupting the gelatin in the video is caused as the bullet rapidly decelerates and transmits energy into the gelatin. The same occurs in human tissue with the pressure wave, or temporary cavity, causing damage to structures around, but not in the direct path of, the bullet.

The pressure wave emanating out from the path of the bullet through the casualty’s neck passed directly through his spinal cord. As it did so, the casualty went into a state of spinal shock, causing him to immediately lose all function of his nervous system below the injury and, while remaining conscious throughout the ordeal, making him temporarily quadriplegic. Spinal shock is often loosely referred to as a spinal concussion, similar to the temporary symptoms experienced following a knock to the head that gradually settle over a period of time. Thankfully, this was the case with the casualty in this case study, with the majority of his nervous system function returning in the hours post-injury, and a gradual recovery of almost all of his nervous functions after years of intensive rehabilitation.

Although making a steady recovery from the spinal shock in the months to years following the injury, a more insidious sequelae from the damage done by the temporary cavity of the bullet began to manifest. Interestingly from a medical perspective, the casualty developed symptoms of traumatic brain injury (TBI) which, while frequently seen in war casualties, is more typically associated with blast injuries, and almost always associated with loss of consciousness. Having spent my previous career in the military medical space, I had never heard of the concept of a TBI from a gunshot wound distal to the head. Having been introduced to the concept, however, and keeping the video image of the temporary cavitation from a high-velocity missile in mind, it makes perfect sense that that same pressure wave that disrupts tissues surrounding the permanent cavity of a bullet could cause significant damage to brain tissue, especially if shot at relatively close range through the neck or upper torso.

In fact, studies have demonstrated that ballistic wounds as distal as the abdomen and thorax can cause a transmitted pressure wave through the brain with enough force to generate a TBI (Courtney & Courtney, 2007). I encourage anyone reading this who has an interest in military medicine or TBIs to look up the Courtney reference, as it has opened my eyes to a new significant risk of TBI resulting from distal gunshot wounds that I was previously oblivious to, which has implications for early management of such injuries. With today’s heightened terrorist threat and recent world events, these military-related wounds may be presenting at a civilian emergency department near any one of us in the near future.

As stated in the introduction, fortunately this story has a happy ending in that the operator who was shot has gone from strength to strength in his recovery and is not showing any sign of slowing down. Frustratingly, despite being on the ground on the day of his injury, I was unable to get to him due to his geographical location and the tactical situation. The heroes of the day (apart from the casualty) were the first responders and the U.S. Aeromedical Evacuation team, who came into a highly complex and dangerous situation to extract the casualty under fire. TacMed Australia extends its sincere gratitude to all the pre-hospital medical practitioners and evacuation elements out there who save lives daily in civilian and military context alike.

As always, comments and questions are welcome.

This article previously published on SOFREP 12.28.2015

References:

Apfelbaum JD, CS, Waldman N 2000, ‘Unstable cervical spine without spinal cord injury in penetrating neck trauma’, American Journal of Emergency Medicine, vol. 18, no. 1, pp. 55-57.

Courtney A, CM 2007, ‘Links between traumatic brain injury and ballistic pressure waves originating in the thoracic cavity and extremities’, Brain Injury, vol. 21, no. 7, pp. 657-662.

Lustenberger T, TP, lam L, Kobayashi L, Inaba K, Plurad D, Branco BC, Demetriades D 2011, ‘Unstable cervical spine fracture after penetrating neck injury: a rare entity in an analysis of 1,069 patients’, Journal of Trauma, vol. 70, no. 4, pp. 870-872.