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Odd Job · November 13, 2006, 08:46 AM

Case number 2 (gunshot spine)

This one is a bit complicated.

A young man sustained a penetrating gunshot wound to the back. On arrival he had localised pain in the lumbar spine, paralysis of one leg and decreased motor and sensation in the other (I did not note at the time which leg was paralysed). These are his initial radiographs:

The bullet entered posteriorly and centrally (yellow arrow). It then caused a fracture of L3 (red arrow) and suffered significant fragmentation, depositing multiple daughter fragments in the wound. The parent fragment (blue arrow) came to rest in front of the spine at the level of L2.
This bullet is obviously jacketed. You can appreciate the difference in density especially on the lateral view (side view) of the spine. It is possible that this was a JHP, but it could also be an FMJ that fragmented upon encountering the spine.
Of course with a situation like this, you have to CT scan the guy:

Now you can appreciate the amount of damage that was done. Again I have indicated some of the many fractures with green arrows. In this case most of the damage to the spinal canal was done by the projectile or daughter fragments of the projectile. I have indicated with orange arrows several examples (not all) where fragments of the projectile are lodged in the spinal canal. Other projectile fragments are indicated with yellow arrows. Note the projectile fragments lodged in the vertebral body in slices 12, 13 and 14. Pieces of the bullet have also been lodged in the region of the fractured posterior elements (best seen on slices 14 and 15). The parent projectile can be seen in the top left corner of slices 3-10. This corresponds to the right hand side of the patient's anatomy. Those streaks that you see emanating from the projectile fragments are a type of imaging artefact associated with metals and other dense materials. It basically results from a failure of the X-ray beam to penetrate the item and therefore the computer software renders the incorrect density (usually a dark or light streak) for the anatomy in the path between the bullet and the CT detector. Similarly if you look at the parent projectile in slices 6 and 7, it appears to have a black hollow. This is a false representation. That could be a solid piece of lead. This happens because the X-ray beam cannot penetrate that large piece of lead and the CT detector therefore gets no data for that region.

This injury is worse than the previous case for the following reasons:

1) The projectile has passed through the spinal canal and deposited projectile fragments within the spinal canal at multiple levels. Bone fragments from the factured posterior elements are also present in the canal.
2) There are more fractures, involving the body and posterior elements of L3, but also the vertebra above is fractured (L2).
3) The possibility exists to damage the spinal cord at the level of L2, and this may very well have happened. It is not possible to determine in all cases where a projectile has passed, but the indications in this case that the spinal cord may have been damaged are compelling, especially when you see the projectile fragment lodged in the canal at the level of L2 (see slice 3).

In both these cases I have not discussed vascular or abdominal organ damage, because the subject here is CNS incapacitation from spinal gunshot wounds. You should note that other factors come into play, depending on the level at which the spine is damaged. There are major vessels running alongside the spine such as the abdominal and thoracic aorta and the inferior vena cava. In the cervical spine you also have the vertebral arteries that pass through two foramena (holes) in the posterior elements on their way to the brain. A gunshot injury to the cervical spine therefore carries the risk of a vascular injury even though the aorta and superior vena cava are out of harm's way. I have one such case in my file where a man sustained a gunshot injury to the neck, resulting in a fractured vertebra and damage to one of the vertebral arteries, but the spinal cord was untouched.

Here is a well illustrated overview of spinal anatomy:

http://www.fleshandbones.com/readingroom/pdf/275.pdf

Edit: the horizontal streaks across slices 2 and 4 are not due to projectile artefact, they are imaging errors.

November 13, 2006, 08:46 AM	#24
Odd Job Senior Member Join Date: January 2, 2006 Location: London (ex SA) Posts: 476	Case number 2 (gunshot spine) This one is a bit complicated. A young man sustained a penetrating gunshot wound to the back. On arrival he had localised pain in the lumbar spine, paralysis of one leg and decreased motor and sensation in the other (I did not note at the time which leg was paralysed). These are his initial radiographs: The bullet entered posteriorly and centrally (yellow arrow). It then caused a fracture of L3 (red arrow) and suffered significant fragmentation, depositing multiple daughter fragments in the wound. The parent fragment (blue arrow) came to rest in front of the spine at the level of L2. This bullet is obviously jacketed. You can appreciate the difference in density especially on the lateral view (side view) of the spine. It is possible that this was a JHP, but it could also be an FMJ that fragmented upon encountering the spine. Of course with a situation like this, you have to CT scan the guy: Now you can appreciate the amount of damage that was done. Again I have indicated some of the many fractures with green arrows. In this case most of the damage to the spinal canal was done by the projectile or daughter fragments of the projectile. I have indicated with orange arrows several examples (not all) where fragments of the projectile are lodged in the spinal canal. Other projectile fragments are indicated with yellow arrows. Note the projectile fragments lodged in the vertebral body in slices 12, 13 and 14. Pieces of the bullet have also been lodged in the region of the fractured posterior elements (best seen on slices 14 and 15). The parent projectile can be seen in the top left corner of slices 3-10. This corresponds to the right hand side of the patient's anatomy. Those streaks that you see emanating from the projectile fragments are a type of imaging artefact associated with metals and other dense materials. It basically results from a failure of the X-ray beam to penetrate the item and therefore the computer software renders the incorrect density (usually a dark or light streak) for the anatomy in the path between the bullet and the CT detector. Similarly if you look at the parent projectile in slices 6 and 7, it appears to have a black hollow. This is a false representation. That could be a solid piece of lead. This happens because the X-ray beam cannot penetrate that large piece of lead and the CT detector therefore gets no data for that region. This injury is worse than the previous case for the following reasons: 1) The projectile has passed through the spinal canal and deposited projectile fragments within the spinal canal at multiple levels. Bone fragments from the factured posterior elements are also present in the canal. 2) There are more fractures, involving the body and posterior elements of L3, but also the vertebra above is fractured (L2). 3) The possibility exists to damage the spinal cord at the level of L2, and this may very well have happened. It is not possible to determine in all cases where a projectile has passed, but the indications in this case that the spinal cord may have been damaged are compelling, especially when you see the projectile fragment lodged in the canal at the level of L2 (see slice 3). In both these cases I have not discussed vascular or abdominal organ damage, because the subject here is CNS incapacitation from spinal gunshot wounds. You should note that other factors come into play, depending on the level at which the spine is damaged. There are major vessels running alongside the spine such as the abdominal and thoracic aorta and the inferior vena cava. In the cervical spine you also have the vertebral arteries that pass through two foramena (holes) in the posterior elements on their way to the brain. A gunshot injury to the cervical spine therefore carries the risk of a vascular injury even though the aorta and superior vena cava are out of harm's way. I have one such case in my file where a man sustained a gunshot injury to the neck, resulting in a fractured vertebra and damage to one of the vertebral arteries, but the spinal cord was untouched. Here is a well illustrated overview of spinal anatomy: http://www.fleshandbones.com/readingroom/pdf/275.pdf Edit: the horizontal streaks across slices 2 and 4 are not due to projectile artefact, they are imaging errors. Last edited by Odd Job; November 13, 2006 at 12:08 PM.