Avascular necrosis of the dens: a follow-up study

In order to determine the long-term consequences of avascular necrosis of the dens following halo-pelvic traction, 83 patients who had had their halo-pelvic apparatus removed at least five years previously were studied. Avascular necrosis of the dens was found in 31 patients (37%) within one year of removal of the apparatus, but after a minimum of five years the early bony changes had resolved and there was no evidence of atlantoaxial instability. However, 19% of patients who had had avascular necrosis had moderate or severe neck symptoms.