Background: Whether or not to remove bullets
or bullet fragments from the spinal column of a neurologically intact
patient has been a subject of continual debate. The controversy
is due in part to a lack of information about the long-term effects
of bullet fragments on spinal cord tissue. Although many studies
have demonstrated the toxic effects of metal fragments on brain
tissue, to our knowledge no one has evaluated the effects of the
metals contained in commercially available bullets on spinal cord
Methods: Copper, aluminum, and lead fragments from
three commercially available bullet cartridges were implanted in
intradural and extradural locations in seventeen New Zealand White
rabbits. At an average of 9.8 months, the metal content of specimens of
blood, cerebrospinal fluid, and liver were determined. The spinal
cords were harvested and examined histologically.
Results: There was a significant increase in the
copper level of blood from the rabbits with an implanted copper fragment
compared with that of the control animals (p = 0.007).
Concentrations of copper and lead were not elevated, compared with
the control values, in the serum or liver. Histological examination of
the spinal cords revealed major destruction of both the axons and
the myelin of the dorsal column adjacent to the intradural copper
fragments. Intradural fragments of lead caused similar destruction of
myelin and axons in the dorsal column, but to a lesser degree. Minimal
spinal cord or meningeal histological changes were noted around
the aluminum intradural fragments, and no pathological changes were
found near any fragments placed in an extradural location.
Conclusions: The results of this study show that
certain metals contained in commercially available bullets can cause
varying degrees of neural destruction independent of the initial
mechanical injury caused by implantation. Of the three metals tested,
copper fragments consistently caused a substantial localized area
of neural injury within the spinal cord.
Clinical Relevance: In our study, copper fragments
caused local neural toxicity involving as much as 10% of
the spinal cord area, suggesting that there may be a scientific basis
for removal of copper fragments lodged in the spinal cord, even
in the absence of a neurological deficit.