Abstract: ObjectiveTo establish a method to induce heterotopic ossification (HO) after spinal cord injury. Methods10 New Zealand White rabbits underwent a complete transection of the thoracic (T₁₀) spinal cord. Just after transection, the right hind limb of every rabbit was immobilized with a plaster support to keep the knee in extension and the hip unrestricted. The plaster was temporarily removed once a day (six times per week) to allow the knees passively mobilized at the maximum range for 5 min. Local swelling, local skin temperature and grade of ossification of the paraplegic limbs were observed. After 5 weeks, the rabbits were sacrificed, and the quadriceps muscles of the right hind limbs were removed for the histological examination. ResultsAfter 5-week immobilization and temporary passive mobilization, HO was successfully induced in all 10 rabbits. There was local skin temperature increase and local swelling in the right hind limbs. The histological changes were similar to those observed in clinical HO. Conclusion5-week immobilization and temporary passive mobilization approach may successfully induce HO, and it may be used to study the pathogenesis of HO after spinal cord injury.

Key words: spinal cord injury, heterotopic ossification, myositis ossificans, animal model, rabbit