Study of ectopic bone formation in experimental spinal cord injured rabbits.

There was no significant difference of incidence of ectopic bone formation between paraplegic rabbits and non-paraplegic rabbits under the same immobilization and passive movement of the posterior legs. This result suggests that ectopic bone may be produced by forcible passive movement of paralytic legs, as legs of paraplegic patients are in an immobilized condition because of the paralysis. Enchondral ossification was significantly observed histologically more frequently in paraplegic rabbits than in non-paraplegic rabbits. We suspect that the reason may be because the paralytic legs are poorly oxygenated because of blood stasis.