For peripheral causalgia, the diagnosis required that the subjects' chronic pain was due to damage to a nerve. The pain was required to be in an anatomical area consistent with the innervation pattern of the damaged nerve (or nerves), and generally, in a hyperalgesic state. In some cases, the nerve damage progressed with secondary changes manifesting themselves. However, this was not a diagnostic requirement. Nerve damage typically resulted from blunt trauma (injury) or other types of injury such as post-surgical nerve cutting or lesioning.
From the 248 patients, 113 radiculomedullary arteries could be clearly evaluated within a neural foramen. The AKA was located in the superior one-half of the foramen in 97% (110). Eighty-eight percent (100) were located in the upper third; 9% (10) were located in the middle third; and 2% (2) were located in the lower third. The AKA was never seen in the inferior one-fifth of the foramen. Eighty-eight percent (100) of the radiculomedullary arteries were located on the left while 17% (20) were located on the right. The radiculomedullary arteries were identified from T2-L3. 92% (110) were located between T8 and L1. 28% (34) were located at T10, the highest incidence.