Localization of foreign bodies in the spinal canal by computer-assisted biplanar digitizer

This study is a report of the use of a computer-assisted biplane digitizer to locate shotgun pellets within the spinal canal in an incompletely paralyzed patient. It was necessary to determine if one or more shotgun pellets were located within the spinal cord of the patient. Because of the profusion of pellets it was not possible to determine which, if any, of the pellets were in the spinal canal by routine roentgenograms. The problem of determining the location of each pellet with respect to the spinal cord was resolved by the use of biplane radiography in conjunction with an x-ray digitizer and a computer program. This report presents the method for localizing foreign bodies and discusses the results of the procedure. It was concluded that the described method successfully located the position of pellets with respect to the spinal column and cord. This method may be useful for locating metallic fragments that have to be surgically removed in other patients sustaining spinal cord injury secondary to single missile wounds.